MedWorm.com provides a medical RSS filtering service. Over 6000 RSS medical sources are combined and output via different filters. This feed contains the latest items from the 'Clinical Biomechanics' source. Thu, 09 Feb 2012 00:02:25 +0100 http://www.medworm.com/index.php?rid=5630887&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003312000046%2Fabstract%3Frss%3Dyes (Source: Clinical Biomechanics) Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5630887 Fri, 27 Jan 2012 04:52:52 +0100 5630887 http://www.medworm.com/index.php?rid=5366767&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311002737%2Fabstract%3Frss%3Dyes (Source: Clinical Biomechanics) Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5366767 Fri, 04 Nov 2011 02:12:22 +0100 5366767 http://www.medworm.com/index.php?rid=5366755&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS026800331100266X%2Fabstract%3Frss%3Dyes (Source: Clinical Biomechanics) Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5366755 Fri, 04 Nov 2011 02:12:21 +0100 5366755 http://www.medworm.com/index.php?rid=5630901&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311002427%2Fabstract%3Frss%3Dyes This study underscores the importance of restoring soft tissues about the ankle to the anatomic condition during reconstruction operations for instability, trauma and arthritis. (Source: Clinical Biomechanics) Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5630901 Mon, 17 Oct 2011 04:00:00 +0100 5630901 http://www.medworm.com/index.php?rid=5630895&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311002415%2Fabstract%3Frss%3Dyes This study measured the short-term changes of protective stepping following waist-pull perturbations in the medio-lateral direction, to identify what, if any, properties of protective stepping are improved with repeated perturbation exposures.Methods: Sixty waist-pulls (2 directions×5 intensities×6 repetitions) from a single session were analyzed separately as early, middle, and late testing periods, for a comparison over time of typical responses. Outcome measures included the number of evoked steps, type of step, incidence of interlimb collisions, and kinematic and kinetic properties of the first step in frequently used crossover-type responses.Findings: Improvements were evident as significantly reduced number of steps and collisions. However, these improvements could not be completel... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5630895 Mon, 17 Oct 2011 04:00:00 +0100 5630895 http://www.medworm.com/index.php?rid=5630894&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311002397%2Fabstract%3Frss%3Dyes Abstract: Background: Spinal cord injury affects walking balance control, which necessitates methods to quantify balance ability. The purposes of this study were to 1) examine walking balance through foot placement variability post-injury; 2) assess the relationship between measures of variability and clinical balance assessments; and 3) determine if spatial parameter variability might be used as a clinical correlate for more complex balance measurements.Methods: Ten persons with spinal cord injury walked without devices on a split-belt treadmill at self-selected speeds. Ten healthy controls walked at 0.3 and 0.6m/s for comparison. Variability of step width and length, anteroposterior and mediolateral foot placements relative to center-of-mass, and margin-of-stability were calculated. Clin... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5630894 Mon, 17 Oct 2011 04:00:00 +0100 5630894 http://www.medworm.com/index.php?rid=5288078&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311002270%2Fabstract%3Frss%3Dyes (Source: Clinical Biomechanics) Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5288078 Thu, 06 Oct 2011 16:19:18 +0100 5288078 http://www.medworm.com/index.php?rid=5630890&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311002403%2Fabstract%3Frss%3Dyes The objective of this was to develop a low back disorder risk model in furniture distribution workers using biomechanical, psychosocial and individual risk factors.Methods: This was a prospective study with a six month follow-up time. There were 454 subjects at 9 furniture distribution facilities enrolled in the study. Biomechanical exposure was evaluated using the American Conference of Governmental Industrial Hygienists (2001) lifting threshold limit values for low back injury risk. Psychosocial and individual risk factors were evaluated via questionnaires. Low back health functional status was measured using the lumbar motion monitor. Low back disorder cases were defined as a loss of low back functional performance of −0.14 or more.Findings: There were 92 cases of meaningful loss in l... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5630890 Wed, 28 Sep 2011 04:00:00 +0100 5630890 http://www.medworm.com/index.php?rid=5630900&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311002208%2Fabstract%3Frss%3Dyes Abstract: Background: Animal studies and clinical trials have suggested that early application of controlled axial micromotion can accelerate healing of long bone fractures compared to rigid fixation. However, experimental investigations of micromotion constructs have been limited to external fixators, which have a higher incidence of complications than intramedullary nails. The purpose of this study was to assess whether a novel intramedullary nail design can generate stimulatory micromotion under minimal weight-bearing loads typical of the early healing period.Methods: Eight cadaver tibiae were reamed, osteotomised, and implanted with commercially-available IM nails fitted with a custom insert that allowed 1mm of axial micromotion after proximal/distal interlocking. Specimens were mounte... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5630900 Thu, 22 Sep 2011 04:00:00 +0100 5630900 http://www.medworm.com/index.php?rid=5630891&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311002257%2Fabstract%3Frss%3Dyes Abstract: Background: Lateral epicondylosis is a prevalent and costly musculoskeletal disorder characterized by degeneration of the common extensor tendon origin at the lateral epicondyle. Grip strength is commonly affected due to lateral epicondylosis. However, less is known about the effect of lateral epicondylosis on other functional parameters such as ability to react to rapid loading.Methods: Twenty-nine lateral epicondylosis participants and ten controls participated in a case-control study comparing mechanical parameters (mass, stiffness and damping), magnetic resonance imaging signal intensity and grip strength of injured and uninjured limbs. A mixed effects model was used to assess the effect of dominance and injury on mechanical parameters and grip strength.Findings: Significant ... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5630891 Wed, 21 Sep 2011 04:00:00 +0100 5630891 http://www.medworm.com/index.php?rid=5630903&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311002221%2Fabstract%3Frss%3Dyes This study (i) determined the immediate lower limb kinematics and muscle activity adaptations, and (ii) evaluated the effect of individual's comfort and foot mobility.Methods: Forty individuals diagnosed with anterior knee pain were measured for lower limb kinematics and electromyographic activity (via surface electrodes) while they jogged in three prefabricated contoured orthoses (hard, medium and soft) and a soft-flat orthosis. Subjects ranked orthoses in order of comfort.Findings: Soft orthoses were more comfortable. No immediate adaptations in kinematics and electromyographic activity were observed when orthoses were added to shoes. There were few effects of perceived comfort and foot mobility, one being a significant interaction in frontal plane hip motion (Pillai's V=0.089, P=0.031) ... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5630903 Mon, 19 Sep 2011 04:00:00 +0100 5630903 http://www.medworm.com/index.php?rid=5630897&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311002245%2Fabstract%3Frss%3Dyes Abstract: Background: Range of motion after hip arthroplasty may be limited by soft tissues around the hip, extra-articular contact and femoral stem-neck contact with the acetabular articular surface. Femoral head–neck diameter ratio is recognized as a major factor influencing hip range of motion. In hip resurfacing, range of motion is constrained by “cup component to femoral neck” contact. To avoid cup-to-bone contact or to increase the degree of flexion at which it occurs, anterior translation of the femoral component relative to the central femoral neck axis may improve anterior head–neck offset and hip flexion. We questioned whether low or high anterior femoral head to neck offset, cup inclination, stem anteversion, and component size influenced postoperative range of motion an... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5630897 Mon, 19 Sep 2011 04:00:00 +0100 5630897 http://www.medworm.com/index.php?rid=5630889&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311002233%2Fabstract%3Frss%3Dyes Abstract: Background: Up to now, plain radiographs are not well suited to assess spinal fusion. Radiostereometric analysis performed for two postures may deliver more reliable results. However, it is unknown, which postures are most suitable for this procedure.Methods: In a finite element study, spinal fusion at the level L4–5 was simulated assuming a posterior approach and the implantation of two cages and a spinal fixation device. The change of the distance between markers in vertebrae adjacent to the cages was calculated for moving from one of the following postures standing, flexion, extension, axial rotation, lying, and extension in a lying position to another. The changes of marker distances were calculated for the intact model, as well as for the situations: directly after surgery... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5630889 Mon, 19 Sep 2011 04:00:00 +0100 5630889 http://www.medworm.com/index.php?rid=5630888&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311002191%2Fabstract%3Frss%3Dyes Abstract: Background: Ventral hernia is a common medical problem. Statistically there are around 10% recurrences of the sickness. The authors' former investigation proved edges of the hernia orifice displacements to be one of the factors causing recurrence. Thus, experimental investigation of the abdomen surface deformation due to some normal activities of people is studied.Methods: Eight slim, healthy people were asked to extremely stretch their abdomens. Bending, stretching and expiration were considered. The deformations registration was made by two cameras located in front of the patient on both sides. Special calculation procedure was used in order to transform characteristic point displacements to strains of abdomen in different directions.Findings: The extreme strains, their localiz... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5630888 Mon, 19 Sep 2011 04:00:00 +0100 5630888 http://www.medworm.com/index.php?rid=5630899&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS026800331100221X%2Fabstract%3Frss%3Dyes This study attempted to regain more normal knee kinematics through a posterior cruciate ligament retaining knee, which simultaneously incorporated convexly lateral tibial plateau and anatomical condylar configuration into the prosthesis design.Methods: Computational simulation was utilized to analyze motion of three-dimensional knee models. Three total knee systems with consistent convex insert design but with different condylar heights of 0, 2.7 and 4.7mm were investigated in present study. Magnetic resonance images of the subject were utilized to construct the bone models and to distinguish the attachment sites of ligaments and tendons. The distal femurs were modeled to rotate about designated flexion axes of femoral components, and the motion of the proximal tibia was unconstrained exce... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5630899 Tue, 13 Sep 2011 04:00:00 +0100 5630899 http://www.medworm.com/index.php?rid=5539635&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001951%2Fabstract%3Frss%3Dyes This study confirms the role of the medial patellofemoral ligament in providing adequate patellar stability during the first 30° of knee flexion. According to our findings, a 10N tension applied to the graft appears sufficient to ensure proper control of patellar tracking whereas 20, 30 and 40N of tension are excessive tension values inducing a major overcorrection in all studied parameters. (Source: Clinical Biomechanics) Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5539635 Mon, 12 Sep 2011 04:00:00 +0100 5539635 http://www.medworm.com/index.php?rid=5539643&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001963%2Fabstract%3Frss%3Dyes Abstract: Background: A stable fixation between femoral head and endoprosthesis taper is necessary to prevent relative motions and corrosion at the taper junction. Although the importance of the component assembly has been recognised, no definitive instructions are available. The purpose of this study was to assess the influence of assembly force, assembly tool and number of hammer strokes on the taper junction strength of various material combinations.Methods: Co–Cr29–Mo (n=10) and Ti–6Al–4V (n=10) neck tapers were assembled with Co–Cr and Al2O3 ceramic heads either by push-on or by impaction with single or multiple hammer blows. The strength of the taper-head connection was evaluated by measuring the head pull-off forces according to ISO 7206-10 and the turn-off moment capacity... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5539643 Fri, 09 Sep 2011 04:00:00 +0100 5539643 http://www.medworm.com/index.php?rid=5630898&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311002178%2Fabstract%3Frss%3Dyes This study aimed to evaluate the knee joint kinematics among patients with reconstruction on the dominant and non-dominant side.Methods: Forty-one subjects with unilateral anterior cruciate ligament reconstruction (19 dominant, 22 non-dominant) were recruited after being discharged from rehabilitation programs. Twenty healthy subjects were recruited as the control group. Six degrees-of-freedom tibiofemoral motion during level walking was determined using a redundant point cluster-based marker set. Tibiofemoral joint motion and its bilateral differences were compared within each group and between groups.Findings: The non-dominant reconstructed knees had less extension compared to their contralateral knees at heel strike and during middle stance phase (P=0.02); whereas, the dominant reconstr... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5630898 Wed, 07 Sep 2011 04:00:00 +0100 5630898 http://www.medworm.com/index.php?rid=5630893&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS026800331100218X%2Fabstract%3Frss%3Dyes Abstract: Background: Establishing changes in net joint power in the lower extremity of patients during recovery of walking might direct gait training in early stroke rehabilitation. It is hypothesized that (1) net joint power in the lower extremity joints would increase in sub-acute stroke patients following gait rehabilitation, and (2) the improvements in net joint power would be significantly correlated with changes in walking speed.Methods: Thirteen sub-acute patients ( (Source: Clinical Biomechanics) Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5630893 Wed, 07 Sep 2011 04:00:00 +0100 5630893 http://www.medworm.com/index.php?rid=5630902&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311002166%2Fabstract%3Frss%3Dyes Abstract: Background: Custom molded insoles with metatarsal supports are used to redistribute excessive loading under the metatarsal heads in patients with metatarsalgia. However, these pressure reductions are usually insufficient for the rheumatoid foot with painful deformed metatarsal heads. We developed an effective insole made by sequential foam padding under successive walking impression.Methods: Seventeen consecutive rheumatoid arthritic outpatients with metatarsal pain participated in this repeated measures study of 7-mm flat Ethylene Vinyl Acetate, custom molded and dynamic impression insoles. Peak plantar pressure, pressure-time integral, contact area and mean force were measured by a Pedar-X mobile system. Pain levels were assessed using a Visual Analog Scale (0–10).Findings: C... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5630902 Mon, 05 Sep 2011 04:00:00 +0100 5630902 http://www.medworm.com/index.php?rid=5630892&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311002130%2Fabstract%3Frss%3Dyes Abstract: Background: There are robust clinical paradigms against the prescription of walking sticks for people with stroke. However, there is little information on the biomechanics of gait with and without these devices to guide clinical practice. Therefore, this study investigated how the use of walking sticks (canes or crutches) affected both the kinematics and kinetics of gait in people with chronic stroke after their walking had stabilized.Methods: Nineteen people with chronic stroke walked at both comfortable and fast speeds. A 3-D motion analysis system and one force platform were used to obtain kinematic and kinetic data of the paretic lower limb during four conditions: With and without walking sticks, and at comfortable and fast speeds. Outcomes included linear kinematics (walking... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5630892 Mon, 05 Sep 2011 04:00:00 +0100 5630892 http://www.medworm.com/index.php?rid=5630896&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311002154%2Fabstract%3Frss%3Dyes Abstract: Background: Short stem prostheses have been developed to preserve the femoral bone stock. The purpose of this study was to evaluate the stress-shielding effect in the proximal femur as well as the micromotion between bone and implant as a measure of primary stability for a new short stem in comparison to a clinically successful short stem and a straight stem.Methods: Using paired fresh human femurs, stress shielding was examined by using tri-axial strain gage rosettes. The strain distribution of the proximal femur was measured before and after implantation of three cementless prostheses of different design concepts and stem lengths. Furthermore, interface motion and rotational stability were investigated under dynamic loading (100–1600N) after 100,000 load cycles using inductiv... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5630896 Fri, 02 Sep 2011 04:00:00 +0100 5630896 http://www.medworm.com/index.php?rid=5539638&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001896%2Fabstract%3Frss%3Dyes The objective in this study is to determine the individual contribution of the ankle torques generated by both legs in balance control during dynamic conditions.Methods: Subjects (6 transfemoral and 8 transtibial amputees) stood on a force platform mounted on a motion platform and were instructed to stand quietly. The experiment consisted of 1 static and 3 perturbation trials of 90s duration each. The perturbation trials consisted of continuous randomized sinusoidal platform movements of different amplitude in the sagittal plane. Weight distribution during the static and dynamic perturbation trials was calculated by dividing the average vertical force below the prosthesis foot by the sum of forces below both feet. The Dynamic Balance Control represents the ratio between the stabilizing mec... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5539638 Fri, 02 Sep 2011 04:00:00 +0100 5539638 http://www.medworm.com/index.php?rid=5148826&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311002099%2Fabstract%3Frss%3Dyes (Source: Clinical Biomechanics) Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5148826 Wed, 24 Aug 2011 19:56:00 +0100 5148826 http://www.medworm.com/index.php?rid=5148810&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001987%2Fabstract%3Frss%3Dyes (Source: Clinical Biomechanics) Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5148810 Wed, 24 Aug 2011 19:55:32 +0100 5148810 http://www.medworm.com/index.php?rid=5539640&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001938%2Fabstract%3Frss%3Dyes Abstract: Background: Repeated episodes of giving way at the ankle may be related to alterations in movement variability.Methods: Eighty-eight recreational athletes (39 males, 49 females) were placed in 4 groups: mechanically unstable, functionally unstable, copers, and controls based on ankle injury history, episodes of giving way, and joint laxity. Lower extremity kinematics and ground reaction forces were measured during single leg landings from a 50% maximum vertical jump in the anterior, lateral, and medial directions. Ensemble curves of 10 trials were averaged and coefficients of variation were identified for ankle, knee, hip, and trunk motion in 3 planes. A loge (ln) transformation was performed on the data. Mixed model analyses of variance (ANOVAs) with Tukey post-hoc tests were ut... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5539640 Wed, 24 Aug 2011 04:00:00 +0100 5539640 http://www.medworm.com/index.php?rid=5539639&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS026800331100194X%2Fabstract%3Frss%3Dyes Abstract: Background: The aim of this study was to determine the difference in activation patterns of the plantar intrinsic foot muscles during two quiet standing tasks with increasing postural difficulty. We hypothesised that activation of these muscles would increase with increasing postural demand and be correlated with postural sway.Methods: Intra-muscular electromyographic (EMG) activity was recorded from abductor hallucis, flexor digitorum brevis and quadratus plantae in 10 healthy participants while performing two balance tasks of graded difficulty (double leg stance and single leg stance). These two standing postures were used to appraise any relationship between postural sway and intrinsic foot muscle activity.Findings: Single leg stance compared to double leg stance resulted in g... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5539639 Wed, 24 Aug 2011 04:00:00 +0100 5539639 http://www.medworm.com/index.php?rid=5539636&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001914%2Fabstract%3Frss%3Dyes Abstract: Background: Lateral wedges reduce the peak knee adduction moment and are advocated for knee osteoarthritis. However some patients demonstrate adverse biomechanical effects with treatment. Clinical management is hampered by lack of knowledge about their mechanism of effect. We evaluated effects of lateral wedges on frontal plane biomechanics, in order to elucidate mechanisms of effect.Methods: Seventy three participants with knee osteoarthritis underwent gait analysis with and without 5° lateral wedges. Frontal plane parameters at the foot, knee and hip were evaluated, including peak knee adduction moment, knee adduction angular impulse, center of pressure displacement, ground reaction force, and knee-ground reaction force lever arm.Findings: Lateral wedges reduced peak knee addu... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5539636 Mon, 22 Aug 2011 04:00:00 +0100 5539636 http://www.medworm.com/index.php?rid=5539641&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001884%2Fabstract%3Frss%3Dyes Abstract: Background: Transfacet pedicle screws are scarcely used in primary posterior fixation, and have limited use unilaterally or with existing anterior instrumentation. Nevertheless, the incomplete literature suggests equivalent or better performance of ipsilateral, bilateral, facet screws compared to bilateral pedicle screws.Methods: Two groups of seven human cadaver spines (L3–S1) were tested under pure moments of 6Nm. Each specimen was tested in a primary and circumferential fixation (Spacer, Spacer+Plate) environment. Both transfacet and bilateral pedicle screws were used as posterior fixation, in separate groups. Motion was obtained at L4–L5 for single-level constructs in flexion–extension, lateral bending and axial rotation modes.Findings: In primary fixation, both transfa... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5539641 Thu, 18 Aug 2011 04:00:00 +0100 5539641 http://www.medworm.com/index.php?rid=5539634&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001902%2Fabstract%3Frss%3Dyes Abstract: Background: Although the squat exercise and its variations are commonly prescribed for anterior cruciate ligament rehabilitation, whether trunk position affects these ligament forces and strains during the squat is unclear. Our purpose was to evaluate the effects of trunk position on anterior cruciate ligament forces and strains during a single-leg squat.Methods: While instrumented for biomechanical analysis, twelve recreationally active subjects performed single-leg squats with minimal and moderate amounts of forward trunk lean. A combination of inverse dynamics, Hill-type muscle modeling, and mathematical computations estimated anterior cruciate ligament forces, strains and quadriceps, hamstrings, and gastrocnemius forces.Findings: The moderate forward trunk lean condition vs. ... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5539634 Tue, 16 Aug 2011 04:00:00 +0100 5539634 http://www.medworm.com/index.php?rid=5539633&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001926%2Fabstract%3Frss%3Dyes Abstract: Background: Biomechanical studies have linked the handrim wheelchair propulsion with a prevalence of upper limb musculoskeletal disorders. The purpose of this study was to examine the influence of the wheelchair settings on upper limb kinematics during wheelchair propulsion. Recordings were made under various wheelchair configuration conditions to understand the effect of wheelchair settings on kinematics parameters such shoulder, elbow and wrist angles.Methods: Ten experts and ten beginners’ subjects propelled an experimental wheelchair on a roller ergometer system at a comfortable speed. Twelve wheelchair configurations were tested. Kinematics were recorded for each configuration. Based on the hand position relatively to the handrim, the main kinematic parameters of wheelchai... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5539633 Tue, 16 Aug 2011 04:00:00 +0100 5539633 http://www.medworm.com/index.php?rid=5539632&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001835%2Fabstract%3Frss%3Dyes This study aimed to quantify glenohumeral contact forces and muscle forces during handcycling and compare them to previous results of handrim wheelchair propulsion.Methods: Ten able-bodied men propelled the handbike on a treadmill at two inclines (1% and 4% with a velocity of 1.66m/s) and two speed conditions (1.39 and 1.94m/s with fixed power output). Three-dimensional kinematics and kinetics were obtained and used as input for a musculoskeletal model of the arm and shoulder. Output variables were glenohumeral contact forces and forces of important shoulder muscles.Findings: The highest mean and peak glenohumeral contact forces occurred at 4% incline (420N, 890N respectively). The scapular part of the deltoideus, the triceps and the trapezius produced the highest force.Interpretation: Due... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5539632 Thu, 11 Aug 2011 04:00:00 +0100 5539632 http://www.medworm.com/index.php?rid=5539642&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001872%2Fabstract%3Frss%3Dyes Abstract: Background: Helically shaped cephalic implants have proven their benefit to provide an improved stabilization of unstable hip fractures. However, cut out ratios up to 3.6% still occur. This in vitro study evaluated the biomechanical performance of a novel cement augmentation technique of the Proximal Femoral Nail Antirotation in surrogate femora.Methods: Four study groups were formed out of 24 polyurethane foam specimens with low density. Proximal Femoral Nail Antirotation blades were implanted, either non-augmented, or augmented using 3ml of injectable Polymethylmethacrylate bone-cement. The influence of implant mal-positioning was investigated by placing the blade either centered in the femoral head or off-centric in an anteroposterior direction. All specimens underwent cyclic ... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5539642 Tue, 09 Aug 2011 04:00:00 +0100 5539642 http://www.medworm.com/index.php?rid=5539644&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001847%2Fabstract%3Frss%3Dyes In this study, a cervical cadaver model is subjected to physiological loads and stabilized with in-line one-screw, and traditional two-screw per vertebral body plates.Methods: Three groups of eight fresh frozen human cadaver cervical spines (C2–C7) were tested by applying pure moments of 1.5Nm. Motion was obtained at C5–C6, and C4–C5/C5–C6 for single-level and bi-level experiments, respectively, in flexion–extension, lateral bending and axial rotation. Specimens were tested, 1) intact, 2) injured (anterior discectomy), 3) with interbody fusion spacer, 4) in-line one-screw plate+spacer, and 5) two-screw plate+spacer, using four available plate brands.Findings: Single-level plating with interbody spacer restricted range-of-motion with respect to the spacer-alone construct in flexio... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5539644 Mon, 08 Aug 2011 04:00:00 +0100 5539644 http://www.medworm.com/index.php?rid=5366763&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001665%2Fabstract%3Frss%3Dyes Abstract: Background: Research has linked knee extensor moment and knee shear force to the non-contact anterior cruciate ligament injury during the landing motion. However, how these biomechanical performance factors relate to knee translations in vivo is not known as knee translations cannot be obtained with traditional motion capture techniques. The purpose of this study was to combine traditional motion capture with high-speed, biplane fluoroscopy imaging to determine relationships between knee extensor moment and knee shear force profiles with anterior and lateral tibial translations occurring during drop landing in female athletes.Methods: 15 females performed drop landings from a height of 40cm while being recorded using a high speed, biplane fluoroscopy system and simultaneously bei... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5366763 Mon, 08 Aug 2011 04:00:00 +0100 5366763 http://www.medworm.com/index.php?rid=5366761&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001628%2Fabstract%3Frss%3Dyes This study suggests that quadriceps and hamstring muscle co-contraction has a potential role in reducing the anterior cruciate ligament strain values when the knee is in deep flexion. These results can be used to gain insight into anterior cruciate ligament injury mechanisms and to design rehabilitation regimens.Highlights: ► With the knee near extension internal torque of tibia increases ACL strain values. ► Near extension combined loading of muscles and internal torque increase ACL strain. ► In deep flexion combined loading of muscles has the potential to reduce ACL strain. (Source: Clinical Biomechanics) Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5366761 Fri, 05 Aug 2011 04:00:00 +0100 5366761 http://www.medworm.com/index.php?rid=5539646&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001860%2Fabstract%3Frss%3Dyes Abstract: Background: The most important issue in the assessment of fracture healing is to acquire information about the restoration of the mechanical integrity of bone. Many researchers have attempted to monitor stiffness either directly or indirectly for the purpose of assessing strength, as strength has been impossible to assess directly in clinical practice. The purpose of this study was thus to determine the relationship between bending stiffness and strength using mechanical testing at different times during the healing process.Methods: Unilateral, transverse, mid-tibial osteotomies with a 2-mm gap were performed in 28 rabbits. The osteotomy site was stabilized using a double-bar external fixator. The animals were divided into four groups (n=7/group/time point; 4, 6, 8 and 12weeks). ... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5539646 Mon, 01 Aug 2011 04:00:00 +0100 5539646 http://www.medworm.com/index.php?rid=5366760&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001616%2Fabstract%3Frss%3Dyes Abstract: Background: While traditional surgical repair of the anterior cruciate ligament is able to restore anterior–posterior knee stability, laxity in the transverse plane remains. Double-bundle reconstruction has demonstrated greater rotational restraint than the single-bundle technique under passive loading conditions; however, no comparison has been made under physiological weight-bearing conditions. The purpose of this study was to determine differences in rotational knee kinematics during a dynamic task in patients who had received either a single- or double-bundle reconstruction.Methods: Twenty-two patients exhibiting isolated anterior cruciate ligament rupture were randomly allocated either a single or double-bundle reconstruction. Three-dimensional knee kinematics were measure... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5366760 Fri, 29 Jul 2011 04:00:00 +0100 5366760 http://www.medworm.com/index.php?rid=5539645&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001823%2Fabstract%3Frss%3Dyes This study assessed medial collateral ligament healing in Yorkshire and red Duroc pigs at the functional (biomechanical) level.Methods: Surgical injury was created in the right hind limb medial collateral ligament of Yorkshire and red Duroc pigs. After 10weeks of healing, low-load (laxity and creep) and high-load (failure) mechanical properties were measured.Findings: Large, complete ligament scars formed by 10weeks post-injury. A differential healing response was observed between the breeds, where red Duroc ligament scars had larger cross-sectional areas, exhibited greater static and total creep responses, failed at greater deformations and strains (P≤0.05), and failed with strong trends for higher loads and lower moduli (P=0.06) than Yorkshire ligament scars.Interpretation: The ligamen... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5539645 Thu, 28 Jul 2011 04:00:00 +0100 5539645 http://www.medworm.com/index.php?rid=5539637&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001859%2Fabstract%3Frss%3Dyes Abstract: Background: The method of attachment of prosthesis to the residual limb (suspension) and socket fitting is a critical issue in the process of providing an amputee with prosthesis. Different suspension methods try to minimize the pistoning movement inside the socket. The Seal-In® X5 and Dermo® Liner by Ossur are new suspension liners that intend to reduce pistoning between the socket and liner. Since the effects of these new liners on suspension are unclear, the objective of this study was to compare the pistoning effect of Seal-In® X5 and Dermo® Liner by using Vicon Motion System.Methods: Six transtibial amputees, using both the Iceross Seal-In® X5 and the Iceross Dermo® Liner, participated in the study. The vertical displacement (pistoning) was measured between the liner a... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5539637 Wed, 27 Jul 2011 04:00:00 +0100 5539637 http://www.medworm.com/index.php?rid=5366764&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS026800331100163X%2Fabstract%3Frss%3Dyes Abstract: Background: Below-knee amputees commonly experience asymmetrical gait patterns and develop comorbidities in their intact and residual legs. Carbon fiber prosthetic feet have been developed to minimize these asymmetries by utilizing elastic energy storage and return to provide body support, forward propulsion and leg swing initiation. However, how prosthetic foot stiffness influences walking characteristics is not well-understood. The purpose of this study was to identify the influence of foot stiffness on kinematics, kinetics, muscle activity, prosthetic energy storage and return, and mechanical efficiency during amputee walking.Methods: A comprehensive biomechanical analysis was performed on 12 unilateral below-knee amputees. Subjects walked overground at 1.2m/s with three prost... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5366764 Thu, 21 Jul 2011 04:00:00 +0100 5366764 http://www.medworm.com/index.php?rid=5366762&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001653%2Fabstract%3Frss%3Dyes Abstract: Background: Subchondral bone stiffness is thought to be involved in osteoarthritis pathogenesis. Our objective was to determine if a CT imaging technique, which measures density in relation to depth from the subchondral surface, could predict the stiffness of proximal tibial subchondral bone. A second objective was to determine whether cartilage degeneration (an indicator of osteoarthritis) affected predictions.Methods: Thirteen proximal tibial compartments (4 medial, 9 lateral) from 10 male donors (age: mean 73.2, SD 10.6years) were scanned using quantitative CT. We assessed average subchondral bone mineral density across different depths (0–2.5, 0–5, 0–10mm) and layers (2.5–5, 5–10mm) measured relative to the subchondral surface. We classified cartilage status as norm... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5366762 Wed, 20 Jul 2011 04:00:00 +0100 5366762 http://www.medworm.com/index.php?rid=5366765&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001586%2Fabstract%3Frss%3Dyes Abstract: Background: The aim of this study is to assess the clinical value of a recently introduced original protocol for full three dimensional analysis of ankle rotations in patients with equinovarus foot.Methods: A preliminary study merging the Total3Dgait protocol and the conventional Vicon® Plug-in-Gait marker-sets on five patients with foot deformity was performed to compare the output exactly over the same gait cycles. In the second study, 15 patients with equinus varus foot were assessed retrospectively by means of the Total3Dgait protocol before and after surgery. Data on ankle kinematics were compared to those of a control group. The Functional Ambulation Categories scale and other goals such as orthosis/aids removal, decrease in foot pain, healing of calluses and sores were co... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5366765 Mon, 18 Jul 2011 04:00:00 +0100 5366765 http://www.medworm.com/index.php?rid=5288091&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001537%2Fabstract%3Frss%3Dyes It was with much interest that I read the recent paper from Blackburn et al. (Blackburn JT, Norcross MF, Padua DA. Influences of hamstring stiffness and strength on anterior knee joint stability. Clin Biomech 2011; 26: 278–83) that utilized the technique that we developed in the early 1990s (see McNair PJ, Wood GA, Marshall RN. Stiffness of the hamstring muscles and its relationship to function in anterior cruciate ligament deficient individuals. Clin Biomech 1992; 7: 131–137). This paper, which Blackburn et al. do not seem to be aware of, showed that hamstring muscle stiffness was moderately correlated with functional ability in anterior cruciate ligament (ACL) deficient subjects, with higher functioning subjects having greater stiffness. A later paper by us also provided evidence of ... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5288091 Mon, 18 Jul 2011 04:00:00 +0100 5288091 http://www.medworm.com/index.php?rid=5032213&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001689%2Fabstract%3Frss%3Dyes (Source: Clinical Biomechanics) Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5032213 Sun, 17 Jul 2011 02:52:25 +0100 5032213 http://www.medworm.com/index.php?rid=5366759&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001641%2Fabstract%3Frss%3Dyes Abstract: Background: Numerous models of elbow prostheses are being used and can be divided into two categories: one being a semi-constrained, linked type; and the other being non-constrained, unlinked type. Recent reports of National Elbow Arthroplasty Registers reveal no significant differences in the survival rates between linked and unlinked prosthesis brands, and the main cause appointed for revision for both types is loosening. Some previous biomechanical studies confirm the presence of abnormal bone stresses for the linked type, which can be associated with the risk of loosening. However for the unlinked type, biomechanical studies are not available that corroborate a loosening risk. It seems, that issue has not yet been fully answered and requires further analysis.Methods: Cortex s... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5366759 Mon, 11 Jul 2011 04:00:00 +0100 5366759 http://www.medworm.com/index.php?rid=5366758&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001562%2Fabstract%3Frss%3Dyes Abstract: Background: Recent in vivo measurements show that the loads acting in the glenohumeral joint are high even during activities of daily living. Wheelchair users are frequently affected by shoulder problems. With previous musculoskeletal shoulder models, shoulder joint loading was mostly calculated during well-defined activities like forward flexion or abduction. For complex movements of everyday living or wheelchair propulsion, the reported loads vary considerably.Methods: Shoulder joint forces and moments were measured with telemeterized implants in 6 subjects. Data were captured on a treadmill at defined speeds and inclinations. Additional measurements were taken in 1 subject when lifting the body from the wheelchair, using his arms only, and in 2 subjects when rapidly accelerati... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5366758 Mon, 04 Jul 2011 04:00:00 +0100 5366758 http://www.medworm.com/index.php?rid=5288089&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001380%2Fabstract%3Frss%3Dyes Abstract: Background: In stroke and multiple sclerosis patients, gait is frequently hampered by a reduced ability to push-off with the ankle caused by weakness of the plantar-flexor muscles. To enhance ankle push-off and to decrease the high energy cost of walking, spring-like carbon-composite Ankle Foot Orthoses are frequently prescribed. However, it is unknown what Ankle Foot Orthoses stiffness should be used to obtain the most efficient gait. The aim of this simulation study was to gain insights into the effect of variation in Ankle Foot Orthosis stiffness on the amount of energy stored in the Ankle Foot Orthosis and the energy cost of walking.Methods: We developed a two-dimensional forward-dynamic walking model with a passive spring at the ankle representing the Ankle Foot Orthosis and... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5288089 Mon, 04 Jul 2011 04:00:00 +0100 5288089 http://www.medworm.com/index.php?rid=5288090&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001525%2Fabstract%3Frss%3Dyes Abstract: Background: Foot-ground clearance during the gait cycle swing phase is a critical locomotor adaptation to uneven terrain and non-optimal lower limb control has been linked to tripping and falling. The aim of this research was to determine ageing effects on bilateral foot-ground clearance during overground and treadmill walking.Methods: Ageing and walking surface effects on bilateral foot trajectory control were investigated in 11 older (mean age 73.8years) and 11 young (mean age 22.5years) participants. First maximum clearance after toe-off, minimum foot-ground clearance and second maximum clearance prior to heel contact were determined from sampled 3-dimensional marker coordinates during preferred-speed treadmill walking and walking overground.Findings: Preferred walking speed w... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5288090 Thu, 30 Jun 2011 04:00:00 +0100 5288090 http://www.medworm.com/index.php?rid=5366757&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001598%2Fabstract%3Frss%3Dyes The objective of this study was to compare the structural stability of different reconstruction techniques.Methods: Six fresh human cadavers (L2-pelvis-femora) were used to compare biomechanical stability after reconstruction using four different techniques: (1) sacral rod reconstruction; (2) bilateral fibular flap reconstruction; (3) four-rod reconstruction; and (4) improved compound reconstruction. After total sacrectomy, the construction was carried out using each method once in each cadaver. Structural stiffness was evaluated by linear and angular ranges of motion. L5 relative shift-down displacement, abduction angle on the coronal plane and rotation angle on the sagittal plane, were calculated based on displacement of the identification point under 500N axial loading. Overall stiffnes... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5366757 Thu, 23 Jun 2011 04:00:00 +0100 5366757 http://www.medworm.com/index.php?rid=5288079&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001392%2Fabstract%3Frss%3Dyes Abstract: Background: The postures of the trunk and of the head relative to the trunk adopted during the specific task of head load carriage were measured for a group of pregnant women and a control group of non-pregnant women because this activity was identified as a risk factor for back pain during pregnancy.Methods: The postural data of the trunk and of the head relative to the trunk were collected using two inclinometer devices and an electrogoniometer, respectively.Findings: During walking, the load on the head caused significantly larger upper trunk extension and smaller flexion of the head relative to the trunk. The amplitude of motion of the upper trunk and of the head relative to the trunk, as measured by the standard deviation of walking angles, was found to decrease as a result ... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5288079 Thu, 23 Jun 2011 04:00:00 +0100 5288079 http://www.medworm.com/index.php?rid=5366766&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001604%2Fabstract%3Frss%3Dyes In this study, we used an overdrilling procedure, which enables consistent modeling of reduced screw stability comparable to compromised cancellous bone. Forty eight adult NZW rabbits were used in this study and all animals underwent bilateral femur implantation. One leg was implanted with the screw containing the bisphosphonate (biocoated group) while the other was used as control (control group) with the screw only. Mechanical testing and micro-CT imaging were used to assess the effect of local drug delivery of Zoledronate on screws fixation at 5 time points.Findings: At the early time points (1, 5, and 10days), no significant difference could be seen between the biocoated and control groups. At 6weeks, the bone volume fraction was significantly higher in the trabecular region of the bio... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5366766 Wed, 22 Jun 2011 04:00:00 +0100 5366766 http://www.medworm.com/index.php?rid=5366756&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001574%2Fabstract%3Frss%3Dyes Abstract: Background: Changes in the mean or median frequency of the electromyographic (EMG) power spectrum are often used to assess skeletal muscle fatigue. A more global analysis of the spectral changes using frequency banding may provide a more sensitive measure of fatigue than changes in mean or median frequency. So, the aim of the present study was to characterize changes in different power spectrum frequency bands and compare these with changes in median frequency.Methods: Twenty male subjects performed isometric contractions of the back muscles in an isometric dynamometer at 30%, 40%, 50% and 60% of maximum voluntary contraction. During each contraction, surface EMG signals were recorded from the right and left longissimus thoracis muscles, and endurance time was measured. The EMG p... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5366756 Wed, 22 Jun 2011 04:00:00 +0100 5366756 http://www.medworm.com/index.php?rid=4947957&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001409%2Fabstract%3Frss%3Dyes (Source: Clinical Biomechanics) Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4947957 Mon, 20 Jun 2011 23:47:11 +0100 4947957 http://www.medworm.com/index.php?rid=4947953&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001410%2Fabstract%3Frss%3Dyes (Source: Clinical Biomechanics) Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4947953 Mon, 20 Jun 2011 23:47:08 +0100 4947953 http://www.medworm.com/index.php?rid=4947937&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001306%2Fabstract%3Frss%3Dyes (Source: Clinical Biomechanics) Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4947937 Mon, 20 Jun 2011 23:47:04 +0100 4947937 http://www.medworm.com/index.php?rid=5288086&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001288%2Fabstract%3Frss%3Dyes Abstract: Background: The present study examines the hand movements of children with cerebral palsy during functional tests and compares the childrens' performance with and without the aid of an orthosis that provides wrist extension and thumb abduction.Methods: The range of motion of the trapeziometacarpal joint was assessed for 32 participants via a reflexive markers image system. Observed motions included flexion–extension and abduction–adduction motions performed in the course of four tests for manual ability; the rest position, lateral and tripod pinches and cylindrical grasp. Muscle strength and manual ability were evaluated using dynamometry and the Jebsen–Taylor test.Findings: The range of motion tests for the rest position, lateral and tripod pinches and cylindrical grasp de... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5288086 Mon, 20 Jun 2011 04:00:00 +0100 5288086 http://www.medworm.com/index.php?rid=5288082&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001513%2Fabstract%3Frss%3Dyes Abstract: Background: The suture-bridge technique using anchors as established transosseous-equivalent technique in arthroscopic rotator cuff repair was compared to a modified transosseous technique suitable for arthroscopic cuff repair.Methods: In 10 fresh-frozen matched pairs of human cadaveric shoulders (mean age 67.1, SD 8.5years), two different surgical techniques of cuff repair were tested: Group 1, using the suture-bridge technique with suture anchors, and Group 2, using two transosseous tunnels with SutureButtons®. Lateral row fixation was performed in both groups using knotless implants. Cyclic displacement to gap formation of 2 and 5mm, linear stiffness, yield load, ultimate load, and mode of failure were recorded.Findings: Gap formation at the tendon-to-bone interface of 2mm oc... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5288082 Mon, 20 Jun 2011 04:00:00 +0100 5288082 http://www.medworm.com/index.php?rid=5288081&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001501%2Fabstract%3Frss%3Dyes Abstract: Background: The fixation of the tendon to the bone remains a challenging problem in the latissimus dorsi tendon transfer for irreparable cuff tears and can lead to unsatisfactory results. A new arthroscopic method of tendon to bone fixation using an interference screw has been developed and the purpose of this study was to compare its biomechanical properties to the ones of a standard fixation technique with anchors.Methods: Six paired fresh frozen cadaveric human humeri were used. The freed latissimus dorsi tendon was randomly fixed to the humeral head with anchors or with interference screw after a tubularization procedure. Testing consisted to apply 200cycles of tensile load on the latissimus dorsi tendon with maximal loads of 30N and 60N, followed by a load to failure test. T... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5288081 Mon, 20 Jun 2011 04:00:00 +0100 5288081 http://www.medworm.com/index.php?rid=5288087&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001550%2Fabstract%3Frss%3Dyes This study aimed to simulate the effects of different modular necks on prevention of prosthetic impingement due to excessive femoral anteversion.Methods: We investigated range of motion without prosthetic impingement by collision detection using implant computer-aided design models of the ANCA-Fit system.Findings: Modular necks could provide an adequate range of motion in cases with up to 60° of femoral anteversion. However, few alternative necks were available in cases with excessive femoral anteversion, while many options could be used for femoral offset and version control in cases with average amounts of femoral anteversion without prosthetic impingement.Interpretation: We conclude that modular necks might provide a marginal advantage over other options such as cemented, conical or mo... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5288087 Thu, 16 Jun 2011 04:00:00 +0100 5288087 http://www.medworm.com/index.php?rid=5288092&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001549%2Fabstract%3Frss%3Dyes We are pleased to learn of Dr. McNair's interest in our paper, as the work that he and his colleagues produced in the aforementioned papers from the early 1990s played an essential role in the development of this line of research. Specifically, their work demonstrating a correlation between hamstring stiffness and functional ability in ACL-deficient individuals led us to the question: “Could higher levels of hamstring stiffness limit ACL loading and injury risk in healthy individuals?” We have cited these papers in previous publications (see Blackburn et al. Clin Biomech 19(1): 36–43, 2004) but chose not to in this instance due to the presence of more recent publications using these same methods. (Source: Clinical Biomechanics) Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5288092 Mon, 13 Jun 2011 04:00:00 +0100 5288092 http://www.medworm.com/index.php?rid=5288084&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001276%2Fabstract%3Frss%3Dyes The objective of this study was to investigate differences in shoulder, elbow and hand kinetics while performing three different SPTs that varied in terms of hand and trunk positioning.Methods: Fourteen unimpaired individuals (8 male and 6 female) performed three variations of sitting pivot transfers in a random order from a wheelchair to a level tub bench. Two transfers involved a forward flexed trunk (head–hips technique) and the third with the trunk remaining upright. The two transfers involving a head hips technique were performed with two different leading hand initial positions. Motion analysis equipment recorded upper body movements and force sensors recorded hand reaction forces. Shoulder and elbow joint and hand kinetics were computed for the lift phase of the transfer.Findings:... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5288084 Mon, 13 Jun 2011 04:00:00 +0100 5288084 http://www.medworm.com/index.php?rid=5288083&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001240%2Fabstract%3Frss%3Dyes Abstract: Background: Baseplate micromotion of the reverse shoulder glenoid component can lead to implant loosening. We hypothesized that a remotely positioned displacement gage measures elastic deformation of the system rather than actual micromotion at the implant/bone interface.Methods: Reverse glenoid components were implanted into polyurethane blocks of 3 different densities. A 700N compressive load was maintained and a vertical 700N shear load was applied for 1000 cycles. In addition to the typical gage measurement, a digital image analysis of micromotion at the implant/block interface using high resolution cameras was performed. The measurements were validated on human specimens. A finite element model was implemented to study the isolated effect of block deformation on baseplate di... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5288083 Thu, 09 Jun 2011 04:00:00 +0100 5288083 http://www.medworm.com/index.php?rid=5288080&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001264%2Fabstract%3Frss%3Dyes Abstract: Background: In vitro investigations have demonstrated the importance of the ribcage in stabilizing the thoracic spine. Surgical alterations of the ribcage may change load-sharing patterns in the thoracic spine. Computer models are used in this study to explore the effect of surgical disruption of the rib–vertebrae connections on ligament load-sharing in the thoracic spine.Methods: A finite element model of a T7–8 motion segment, including the T8 rib, was developed using CT-derived spinal anatomy for the Visible Woman. Both the intact motion segment and the motion segment with four successive stages of destabilization (discectomy and removal of right costovertebral joint, right costotransverse joint and left costovertebral joint) were analyzed for a 2000Nmm moment in flexion/e... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5288080 Thu, 09 Jun 2011 04:00:00 +0100 5288080 http://www.medworm.com/index.php?rid=5288088&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001252%2Fabstract%3Frss%3Dyes Abstract: Background: Step-up exercise is one of the most commonly utilized exercises during rehabilitation of patients after both anterior cruciate ligament (ACL) injury and reconstruction. Currently, insurance providers increasingly required a trial of intensified rehabilitation before surgical reconstruction is attempted. The purpose of this study was to investigate whether this “safe” rehabilitation exercise in the setting of ACL deficiency can cause altered knee kinematics.Methods: Thirty patients with unilateral ACL rupture were recruited for this study. The mean time from injury was 3.3months. Tibiofemoral kinematics were determined during a step-up exercise using a combination of magnetic resonance imaging (MRI), dual fluoroscopy and advanced computer modeling.Findings: The ACL... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5288088 Wed, 08 Jun 2011 04:00:00 +0100 5288088 http://www.medworm.com/index.php?rid=5148824&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001239%2Fabstract%3Frss%3Dyes Abstract: Background: Dynamic in-shoe plantar pressure assessment is used both in research and clinical practice to evaluate therapeutic footwear interventions in neuropathic diabetic patients. The aim was to determine the required number of footsteps for reliable and valid in-shoe plantar pressure data in these patients.Methods: In 30 neuropathic diabetic patients wearing custom-made therapeutic footwear, in-shoe plantar pressures were measured for a minimum of 20 midgait walking steps per foot. For each incremental number of steps and for each of six anatomical regions per foot, peak pressure, pressure–time integral, contact area, contact time, and force–time integral were calculated. Reliability was assessed by calculating intraclass correlation coefficients. Validity was assessed b... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5148824 Sun, 05 Jun 2011 23:00:00 +0100 5148824 http://www.medworm.com/index.php?rid=5148820&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001227%2Fabstract%3Frss%3Dyes Abstract: Background: Increased impulsive loading and muscle co-contraction during gait have been observed in individuals with knee osteoarthritis. Proprioceptive deficits in this population may contribute to these effects. Proprioception has been shown to improve with the combination of stochastic resonance electrical stimulation and a knee sleeve in knee osteoarthritis. Our goal was to determine whether stochastic resonance stimulation combined with a knee sleeve would decrease impulsive loading rates and muscle co-contraction during gait in knee osteoarthritis.Methods: Gait kinetics, kinematics and muscle activity were assessed during walking in subjects with knee osteoarthritis during three different conditions: no stochastic resonance/no sleeve (control), stochastic resonance at 75% t... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5148820 Thu, 02 Jun 2011 23:00:00 +0100 5148820 http://www.medworm.com/index.php?rid=5148814&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001203%2Fabstract%3Frss%3Dyes Abstract: Background: Repair of the dorsal component of the scapholunate ligament alone is the usual surgical treatment for scapholunate injuries. Recent literature has suggested that additionally repairing the palmar component of the scapholunate ligament leads to improved and lasting clinical outcomes. The aim of this study was to determine the biomechanical properties of both portions of scapholunate ligaments derived from the same wrist and compare them with the whole scapholunate ligament. The goal was to further elucidate the importance of the palmar portion of the scapholunate ligament from a biomechanical perspective.Methods: Scapholunate ligaments and their components were harvested from the same fresh frozen cadaveric wrists. Force at failure and stiffness were measured.Findings:... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5148814 Wed, 01 Jun 2011 23:00:00 +0100 5148814 http://www.medworm.com/index.php?rid=5148823&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001197%2Fabstract%3Frss%3Dyes Abstract: Background: Information is limited about the relationships between clinical measures of static foot posture and peak plantar pressures under the medial column of the foot. The purpose was to examine these relationships during static standing and walking.Methods: A single-group exploratory design using correlation and regression was used to determine relationships. Ninety-two healthy volunteers participated. Clinical measures of static foot posture including arch index, navicular drop and navicular drift were obtained during static standing. Peak plantar pressures under the hallux, medial forefoot, medial midfoot, and medial rearfoot were obtained during standing and walking.Findings: Static foot posture was related to peak plantar pressures during standing and walking, but the st... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5148823 Tue, 31 May 2011 23:00:00 +0100 5148823 http://www.medworm.com/index.php?rid=5148821&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001215%2Fabstract%3Frss%3Dyes Abstract: Background: Muscle mechanical work is likely affected by gait abnormalities in hemiparetic walking during the paretic pre-swing phase (i.e., double support phase preceding paretic toe-off). Previous experimental studies suggest that muscle work may be decreased in the paretic leg, but paretic work may have been underestimated since experimental approaches based on net joint moments do not account for co-contraction of antagonist muscles. Also, whether the non-paretic leg does more work compared to control subjects at matched speeds and how work generation may differ between hemiparetic subjects walking with different self-selected speeds remains unknown.Methods: Three-dimensional forward dynamics simulations of two representative hemiparetic subjects walking with different self-s... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5148821 Tue, 24 May 2011 23:00:00 +0100 5148821 http://www.medworm.com/index.php?rid=5148812&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001033%2Fabstract%3Frss%3Dyes Abstract: Background: Despite surgical advances, repair of rotator cuff tears is associated with 20–70% incidence of recurrent tearing. The tension required to repair the torn tendon influences surgical outcomes and may be dependent on the gap length from torn tendon that must be spanned by the repair. Detailed understanding of forces throughout the range of motion (ROM) may allow surgeons to make evidence-based recommendations for post-operative care.Methods: We used a computational shoulder model to assess passive tension and total moment-generating capacity in supraspinatus for repairs of gaps up to 3cm throughout the shoulder (ROM).Findings: In 60° abduction, increased gap length from 0.5cm to 3cm caused increases in passive force from 3N to 58N, consistent with those seen during cl... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5148812 Thu, 19 May 2011 23:00:00 +0100 5148812 http://www.medworm.com/index.php?rid=5148822&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS026800331100101X%2Fabstract%3Frss%3Dyes Abstract: Background: Botulinum toxin is commonly used to treat spastic equinus foot. This treatment seems to improve gait in hemiplegic patients when used alone or combined with an ankle-foot orthosis. However, the nature and effects of this improvement have until now rarely been studied. The aim of this study was to quantify the impact of a Botulinum toxin injection in the triceps surae of hemiplegic patients with equinus foot, used either alone or in combination with an ankle-foot orthosis, on the kinematics and dynamics of the paretic lower limb, and to determine the advantage of combining an ankle-foot orthosis with this pharmacological treatment.Methods: Patients were assessed using gait analysis to measure spatio-temporal, kinematic and dynamic parameters of the gait cycle before Bo... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5148822 Tue, 17 May 2011 23:00:00 +0100 5148822 http://www.medworm.com/index.php?rid=5148817&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001021%2Fabstract%3Frss%3Dyes This study demonstrates that the magnetic resonance elastography technique is sensitive enough to detect changes in muscle mechanical properties for children, middle-aged and young adults and could provide clinicians with a muscle reference data base as a function of age, improving the diagnosis of muscular dystrophy. (Source: Clinical Biomechanics) Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5148817 Sun, 15 May 2011 23:00:00 +0100 5148817 http://www.medworm.com/index.php?rid=5148811&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001045%2Fabstract%3Frss%3Dyes Abstract: Background: Antagonistic activation of abdominal muscles and increased intra-abdominal pressure are associated with both spinal unloading and spinal stabilization. Rehabilitation regimens have been proposed to improve spinal stability via selective recruitment of certain trunk muscle groups. This biomechanical analytical study addressed whether lumbar spinal stability is increased by such selective activation.Methods: The biomechanical model included anatomically realistic three-layers of curved abdominal musculature, rectus abdominis and 77 symmetrical pairs of dorsal muscles. The muscle activations were calculated with the model loaded with either flexion, extension, lateral bending or axial rotation moments up to 60 Nm, along with intra-abdominal pressure up to 5 or 10 kPa (37... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5148811 Sun, 15 May 2011 23:00:00 +0100 5148811 http://www.medworm.com/index.php?rid=5032222&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000453%2Fabstract%3Frss%3Dyes Abstract: Background: Studies on the biomechanical properties of meniscus repairs are usually performed at room instead of body temperature. However, various all-inside meniscal repair devices include bioabsorbable materials, which are mechanically sensitive to higher environmental temperatures. Therefore, we hypothesize that current test standards may systematically lead to a false overestimation of their performance.Methods: In 84 cadaveric bovine lateral menisci, an artificial vertical lesion was repaired with different all-inside meniscal repair devices (FasT-Fix, FasT-Fix AB, RapidLoc, Meniscus Arrow, Meniscus Screw) compared to a vertical inside-out Ethibond Excel 2.0 suture loop. Maximum load-to-failure, stiffness, and failure mode were tested in a uniaxial distraction loading at 20... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5032222 Sun, 15 May 2011 23:00:00 +0100 5032222 http://www.medworm.com/index.php?rid=5288085&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000969%2Fabstract%3Frss%3Dyes This study investigated three methods to determine excursions of the flexor digitorum superficialis tendon and median nerve using several motions.Methods: Twenty-five participants (mean age 37.2years SD 13.4) were classified as healthy (n=16), self-reported distal upper extremity cumulative trauma disorders (6), or wheelchair users (3). Static carpal tunnel measurements were taken and displacements of the index flexor digitorum superficialis tendon and median nerve were determined via the velocity time integral and post hoc integration of the Doppler ultrasound waveform using a 12–5MHz linear array transducer, as well as using predictive equations.Findings: Median nerves in symptomatic wrists were larger than healthy wrists by 4.2mm2 (left) and 4.1mm2 (right) proximally to less than 1.4m... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5288085 Tue, 10 May 2011 04:00:00 +0100 5288085 http://www.medworm.com/index.php?rid=5148813&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001057%2Fabstract%3Frss%3Dyes Abstract: Background: Patients with pronounced spasticity reveal difficulties in hand opening during the approaching grasping phase. The general description and assessment procedures of reach-to-grasp movement for rehabilitation purposes is still not established. There is a necessity to develop a universal methodology to describe the approaching phase in grasping which would allow clinical evaluation of movement pathologies.Methods: In the paper, the evaluation of approaching trajectories assessed during grasping by healthy subjects is described. The experiment, undertaken by 7 healthy volunteers, consisted of grasping three different stationary objects positioned in various poses by a robot. 3D recordings of the hand and fingertip trajectories were performed. The kinematic trajectories of... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5148813 Mon, 09 May 2011 23:00:00 +0100 5148813 http://www.medworm.com/index.php?rid=4947956&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000933%2Fabstract%3Frss%3Dyes Abstract: Background: Changes in impulse during the first rocker (braking force) and third rocker (propulsion force) may affect changes in gait speed after orthotic intervention. The purpose of this investigation was to objectively measure changes in impulse during double support and correlate those findings to changes in gait speed with and without ankle foot orthosis in individuals with hemiplegia.Methods: Fifteen adults with stroke-related hemiplegia walked with and without ankle foot orthosis while foot pressure data was collected bilaterally. Outcome measures included: gait cycle time (s), mean force (N), and impulse (Ns) in the wholefoot, hindfoot, forefoot, and toe box during initial double support and terminal double support.Findings: Time significantly decreased during the entire ... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4947956 Sun, 08 May 2011 23:00:00 +0100 4947956 http://www.medworm.com/index.php?rid=5148819&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000994%2Fabstract%3Frss%3Dyes Abstract: Backgrounds: The post-cam design of contemporary posterior stabilized knee prosthesis can be categorized into flat-on-flat or curve-on-curve contact surfaces. The curve-on-curve design has been demonstrated its advantage of reducing stress concentration when the knee sustained an anteroposterior force with tibial rotation. How the post-cam design affects knee kinematics is still unknown, particularly, to compare the difference between the two design features. Analyzing knee kinematics of posterior stabilized knee prosthesis with various post-cam designs should provide certain instructions to the modification of prosthesis design.Methods: A dynamic knee model was utilized to investigate tibiofemoral motion of various post-cam designs during high knee flexion. Two posterior stabili... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5148819 Thu, 05 May 2011 23:00:00 +0100 5148819 http://www.medworm.com/index.php?rid=5148818&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001008%2Fabstract%3Frss%3Dyes Abstract: Background: Hamstrings loading has previously been shown to increase tibiofemoral posterior translation and external rotation, which could contribute to patellofemoral malalignment and elevated patellofemoral pressures. The current study characterizes the influence of forces applied by the hamstrings on patellofemoral kinematics and the pressure applied to patellofemoral cartilage.Methods: Ten knees were positioned at 40°, 60° and 80° of flexion in vitro, and loaded with 586N applied through the quadriceps, with and without an additional 200N applied through the hamstrings. Patellofemoral kinematics were characterized with magnetic sensors fixed to the patella and the femur, while the pressure applied to lateral and medial patellofemoral cartilage was measured with pressure se... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5148818 Wed, 04 May 2011 23:00:00 +0100 5148818 http://www.medworm.com/index.php?rid=5148815&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000982%2Fabstract%3Frss%3Dyes Abstract: Background: Hip mobility is known to affect lumbar spine motion, yet the literature is unclear as to what constitutes normal, limited or excessive motion, given differences in methods, postures, age, etc. The purpose of this study was to establish normative and percentile data for hip rotation and extension, in a young adult male population, using varying methods of quantification.Methods: 77 males (age 18–35) were recruited. Position data was captured using the Vicon Motion capture system, as participants were passively positioned in hip extension (using the Modified Thomas test) and prone hip rotation. 22 of these participants also had measurements obtained with a goniometer. 3D hip extension angles were calculated using Euler angles, and compared to those calculated in 2D. G... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5148815 Wed, 04 May 2011 23:00:00 +0100 5148815 http://www.medworm.com/index.php?rid=5148816&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000970%2Fabstract%3Frss%3Dyes Abstract: Background: Cementless hip prostheses with different offsets are frequently used to restore the rotation center of the hip. However, a rising offset is theoretically associated with a potential risk for increased interface stresses and early loosening.Methods: To assess this potential risk for cementless stems, the primary stability of the CLS Spotorno stem was examined with respect to three different femoral neck versions (125°, 135° and 145°) measuring 3-dimensional micromotions. For this purpose 18 stems were implanted in composite femurs and tested dynamically using physiological loading conditions considering the necessary adaptation according to the different offsets. Additionally the deformations at the surface of the composite femur were recorded to draw conclusions ab... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5148816 Mon, 02 May 2011 23:00:00 +0100 5148816 http://www.medworm.com/index.php?rid=4947943&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003310003062%2Fabstract%3Frss%3Dyes Abstract: Background: The purpose of this study was to compare pelvis–trunk coordination and coordination variability over a range of walking and running speeds between three groups of runners; runners with low to moderate low back pain; runners who had recovered from a single bout of acute low back pain; and runners who had never experienced any symptoms of low back pain.Methods: Pelvis and trunk kinematic data were collected as speed was systematically increased on a treadmill. Coordination between pelvis and trunk in all three planes of motion was measured using continuous relative phase, and coordination variability was defined as the standard deviation of this measure.Findings: Oswestry Disability Index indicated the low back pain group was high functioning (mean 7.9% out of 100%). ... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4947943 Mon, 02 May 2011 23:00:00 +0100 4947943 http://www.medworm.com/index.php?rid=4772570&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311001070%2Fabstract%3Frss%3Dyes (Source: Clinical Biomechanics) Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4772570 Mon, 02 May 2011 21:25:33 +0100 4772570 http://www.medworm.com/index.php?rid=5032221&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000702%2Fabstract%3Frss%3Dyes Abstract: Background: The goal of this study was to determine if increasing strength in primary knee extensors and flexors would directly affect net knee joint moments during a common functional task in persons with knee osteoarthritis.Methods: An exploratory single sample clinical trial with pre-post treatment measures was used to study volunteers with clinical diagnosis of mild knee osteoarthritis (OA) in one knee. Subjects participated in an individually supervised training program 3 times a week for eight weeks consisting of progressive resistive exercises for knee extensors and knee flexors. Pre and post training outcome assessments included: 1. Net internal knee joint moments, 2. Electromyography of primary knee extensors and flexors, and 3. Self-report measures of knee pain and func... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5032221 Thu, 21 Apr 2011 23:00:00 +0100 5032221 http://www.medworm.com/index.php?rid=5032227&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000891%2Fabstract%3Frss%3Dyes Abstract: Background: Increased plantar pressures have been shown to be a risk factor in ulceration of the neuropathic foot. Prescriptive footwear is a common medical treatment, yet evidence regarding the efficacy of these prescriptions is underdeveloped. The purpose of this study is to determine the off-loading properties of four provisional shoes; a rocker sole compared to a flat sole shoe with and without the addition of a 1.25cm plastizote insert.Methods: Fifteen subjects with peripheral neuropathy and a normal longitudinal arch were recruited to compare four types of provisional (post-operative) footwear. Plantar surface foot pressures were measured while wearing a rocker sole shoe or a flat stiff sole shoe. Both shoes were worn with and without a 1.25cm plastizote insert. Peak planta... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5032227 Wed, 20 Apr 2011 23:00:00 +0100 5032227 http://www.medworm.com/index.php?rid=5148825&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000945%2Fabstract%3Frss%3Dyes Abstract: Background: It has been proposed that walking footwear enhances postural stability in healthy older adults. The aim of the study is to evaluate differences between two different types of athletic footwear in relation to postural stability in healthy older adults.Methods: A convenience sample of 21 healthy older adults with mean (SD) of 74 (5) years was recruited. Postural stability was measured using a force plate for anterior–posterior (AP) and mediolateral (ML) centre of pressure excursion for 30s with eyes closed and open using two different types of athletic footwear. Each participant performed three repetitions of bipedal standing. Two-way analysis of variance tested the interaction effect of the footwear and eye conditions on anterior–posterior (AP) and mediolateral (ML... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5148825 Sun, 17 Apr 2011 23:00:00 +0100 5148825 http://www.medworm.com/index.php?rid=5032228&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000957%2Fabstract%3Frss%3Dyes This study examined the effects of unilateral and bilateral use of insoles having medial arch supports and of different inclinations on the frontal plane external hip, knee, subtalar moments and pelvic alignment.Methods: Kinetic and kinematic gait parameters were collected from 21 patients with primary medial knee osteoarthritis. The insoles' inclinations were 0, 6 and 11°, where each of the 6° and 11° was used once unilaterally and another bilaterally while the 0° was used bilaterally as a control.Findings: The Multivariate Analysis of Variance revealed significant increase in the external subtalar eversion moment using either of the 6° or 11° laterally wedged vs the 0° non-wedged insole conditions (P=0.003). Moreover, there were significant increases in the external eversion momen... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5032228 Sun, 17 Apr 2011 23:00:00 +0100 5032228 http://www.medworm.com/index.php?rid=4947955&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000921%2Fabstract%3Frss%3Dyes Abstract: Background: Elevated plantar loading has been implicated in the etiology of plantar ulceration in individuals with diabetes mellitus and peripheral neuropathy. Total contact casts and cast walker boots are common off-loading strategies to facilitate ulcer healing and prevent re-ulceration. The purpose of this study was to compare off-loading capabilities of these strategies with respect to plantar loading during barefoot walking.Methods: Twenty-three individuals with diabetes, peripheral neuropathy, and plantar ulceration were randomly assigned to total contact cast (n=11) or removable cast walker boot (n=12). Each subject underwent plantar loading assessment walking barefoot and wearing the off-loading device. Analysis of covariance was used to compare loading patterns in the of... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4947955 Thu, 14 Apr 2011 23:00:00 +0100 4947955 http://www.medworm.com/index.php?rid=5032217&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000660%2Fabstract%3Frss%3Dyes Abstract: Background: Many studies show good clinical results after proximal row carpectomy. Some biomechanical consequences are documented, but to our knowledge muscle moment arm variations have not previously been quantified.Methods: In five fresh–frozen wrist, kinematics and tendon excursions were measured using a 3D electrogoniometer and Linear Variable Differential Transformers (SOLARTRON Inc., AMETEK Advanced Measurement Technology, Inc, 801 South Illinois Avenue, Oak Ridge, TN 37831-2011, USA), respectively, in three conditions: intact wrist, after posterior capsulotomy and after proximal row carpectomy. Mean pivot point, defined as the point whose sum of the squared distances to the helical axes is minimum, wrist range of motion and mean moment arms were measured during dorso-pal... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5032217 Sun, 10 Apr 2011 23:00:00 +0100 5032217 http://www.medworm.com/index.php?rid=5032224&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000726%2Fabstract%3Frss%3Dyes Abstract: Background: Femoral osseointegrated implants represent a new development in amputee rehabilitation, eliminating socket pressure discomfort, improving hip range of movement and facilitating prosthetic limb attachment. A clinical aspect that has not previously been reported on is the function of muscles in the residuum with implications concerning energy expenditure, hip-hiking and viability of the electrogram as a myoprocessor. Typically, amputees fitted with osseointegrated fixation have shorter residuums and weaker attachment of cleaved muscles. Function of muscle can be assessed by surface electromyography through changes in amplitude and median frequency of the signal.Methods: Five male transfemoral amputees with osseointegrated fixations participated together with a control g... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5032224 Thu, 07 Apr 2011 23:00:00 +0100 5032224 http://www.medworm.com/index.php?rid=4772575&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000222%2Fabstract%3Frss%3Dyes Abstract: Background: Radiocapitellar arthroplasty is indicated for capitellar deficiency. Although current implants employ a spherical capitellar surface, the capitellum is elliptical. This has implications for congruency and wear in capitellar arthroplasty. Our objective was to evaluate the contact mechanics of radiocapitellar arthroplasty. We hypothesized that capitellar replacement would decrease joint contact area relative to the native articulation; and an anatomical implant design would replicate more normal contact morphology than a spherical implant.Methods: Eight paired humeri and radii were potted in a custom jig. A compressive load of 85N was applied with the articulation flexed at 45° in neutral forearm rotation. Joint casts were made and the articular contact area and shape ... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4772575 Thu, 07 Apr 2011 23:00:00 +0100 4772575 http://www.medworm.com/index.php?rid=5032218&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000714%2Fabstract%3Frss%3Dyes Abstract: Background: Flexor carpi ulnaris muscle tenotomy and transfer to the extensor side of the wrist are common procedures used to improve wrist position and dexterity in patients with cerebral palsy. Our aim was to determine whether this muscle still influences wrist torque even after tenotomy of its distal tendon.Methods: Intra-operatively, we determined in vivo maximal wrist torque in hemiplegic cerebral palsy patients (n=15, mean age 17years) in three conditions: 1) with the arm and the muscle intact; 2) after tenotomy of the flexor carpi ulnaris just proximal to the pisiform bone, with complete release from its insertion; and 3) after careful dissection of the belly of the muscle from its fascial surroundings up until approximately halfway its length.Findings: After tenotomy of t... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5032218 Wed, 06 Apr 2011 23:00:00 +0100 5032218 http://www.medworm.com/index.php?rid=5032214&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000684%2Fabstract%3Frss%3Dyes Abstract: Background: Individuals with diabetic neuropathy sway more than control individuals while standing. This review specifically evaluated whether peripheral sensory neuropathy can be the only fundamental reason accounting for significant increased sway within this population.Methods: Twenty-six experimental articles were selected using MEDLINE and reference lists of relevant articles. The articles chosen investigated kinematic data of postural behaviour in controls and individuals with diabetic neuropathy during stance. Results of literature were compared with four expectations related to the peripheral sensory neuropathy fundamental hypothesis.Findings: Consistent with the peripheral sensory neuropathy hypothesis, the literature showed that individuals with diabetic neuropathy sway... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5032214 Thu, 31 Mar 2011 23:00:00 +0100 5032214 http://www.medworm.com/index.php?rid=4947954&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000672%2Fabstract%3Frss%3Dyes Abstract: Background: Chronic ulnar nerve compression is believed to be the primary cause of sensory and motor impairments of the hand in cyclists, a condition termed Cyclist's Palsy. The purpose of this study was to quantitatively evaluate the effects that hand position and glove type can have on pressure over the ulnar nerve, specifically in the hypothenar region of the hand.Methods: Thirty-six experienced cyclists participated. Subjects rode at a constant cadence and power output on a stationary bicycle with their hands in the tops, drops and hoods of a standard drop handlebar. A high resolution pressure mat was used to record hand pressure with no gloves, unpadded gloves, foam-padded gloves and gel-padded gloves. Wrist posture was simultaneously monitored with a motion capture system. ... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4947954 Thu, 31 Mar 2011 23:00:00 +0100 4947954 http://www.medworm.com/index.php?rid=4947944&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000441%2Fabstract%3Frss%3Dyes Abstract: Background: Despite a high prevalence of rotator cuff impingements or tears in the elderly population, little research has focused on how this injured population adapts to perform tasks of daily living. The current study investigated the influence of rotator cuff impingements in this population on kinematics and shoulder loading differences, while completing activities of daily living.Methods: Upper limb and trunk movement was measured for thirteen asymptomatic elderly and ten elderly subjects with rotator cuff impingements during five range of motion tasks and six activities of daily living. Thoracohumeral kinematics was derived from this data.Findings: Symptomatic populations showed significantly decreased ranges of flexion/extension, abduction and internal and external rotatio... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4947944 Thu, 31 Mar 2011 23:00:00 +0100 4947944 http://www.medworm.com/index.php?rid=5032219&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000696%2Fabstract%3Frss%3Dyes Abstract: Background: Recent research demonstrated that intermittent claudication patients have increased gait variability prior to the onset of claudication. However, it is unknown if these patients experience additional gait adaptations after the onset of claudication. Thus, we sought to determine how gait variability is affected by claudication in an effort to contribute to improved clinical management.Methods: Twenty-six intermittent claudication patients and 20 controls walked on a treadmill at self-selected speed; intermittent claudication patients were tested before (pain free) and after (pain) the onset of claudication. Variability of the ankle, knee, and hip joint angles was assessed using the largest Lyapunov exponent, standard deviation and coefficient of variation. Dependent t-... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5032219 Tue, 29 Mar 2011 23:00:00 +0100 5032219 http://www.medworm.com/index.php?rid=4647116&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS026800331100074X%2Fabstract%3Frss%3Dyes (Source: Clinical Biomechanics) Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4647116 Tue, 29 Mar 2011 20:54:33 +0100 4647116 http://www.medworm.com/index.php?rid=5032216&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000659%2Fabstract%3Frss%3Dyes Abstract: Background: Rehabilitation of patients with joint affecting diseases makes an appeal to available compensating motions. Objective information about compensatory motions is required for clinical decision-making. Our objective was to quantify resulting shoulder and arm motions from limited elbow mobility during activities of daily living in healthy controls and patients.Methods: Ten hemophilia patients with reduced elbow motion and ten controls volunteered in a kinematic motion analysis of thorax, shoulder, arm and wrist during 5 experimental activities of daily living. In controls, the elbow range of motion was limited by an elbow brace with variable flexion and extension stops. The elbow angle of patients was not intervened. Outcome variables were minimal required elbow range of ... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5032216 Sun, 27 Mar 2011 23:00:00 +0100 5032216 http://www.medworm.com/index.php?rid=5032229&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000635%2Fabstract%3Frss%3Dyes Abstract: Background: Posttraumatic joint contracture is a common complication of intraarticular injuries and an associated traumatic hemarthrosis could be of importance for its development. The purpose of this investigation was to determine whether the source of the hemarthrosis (peripheral blood vs. bleeding from the bone marrow) affects the amount of contracture and its reversibility and biomechanical properties.Methods: 46 New Zealand White rabbits were divided in 6 groups and 33 underwent 8weeks immobilization with either hemarthrosis from bone marrow or peripheral blood. 16 rabbits underwent remobilization for another 8weeks. 7 animals had only hemarthrosis (bone marrow) for 8weeks, while 6 were used as controls. Analysis included mean contracture angle and biomechanical variables.Fi... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5032229 Mon, 21 Mar 2011 00:00:00 +0100 5032229 http://www.medworm.com/index.php?rid=4947948&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000398%2Fabstract%3Frss%3Dyes Abstract: Background: Repetitive kneeling in certain occupations, hobbies and cultures is associated with tibiofemoral joint osteoarthritis. The biomechanics of kneeling is therefore of interest. This cadaveric study investigated tibiofemoral joint contact areas, pressures, and kinematics in response to kneeling.Methods: Five human cadaveric knees were subjected to simulated kneeling at flexion angles of 90°, 105°, 120°, and 135°. Different anterior forces were applied to the knee to simulate crouching (no force), double stance kneeling (339N of force), and single stance kneeling (678N of force). Tibiofemoral joint kinematics, contact areas, and pressures were measured.Findings: Kneeling produced tibial posterior translation and external rotation. Posterior translation was significantl... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4947948 Fri, 18 Mar 2011 00:00:00 +0100 4947948 http://www.medworm.com/index.php?rid=4947942&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000386%2Fabstract%3Frss%3Dyes This study describes multi-segmental trunk motion based on a new technique which is a compromise between technical limitations, implied with the experiments, and clinical relevance.Methods: The thorax segment was tracked by the optimal spatial matching of four thoracic markers. The separate bi-dimensional shoulder line rotations and translations with respect to the thorax were calculated by markers on the two acromions. Spine motion was characterised by a 5-link-segment model from additional four skin markers, in the anatomical reference frame based on four pelvic spine markers. These 14 markers were tracked in 10 healthy subjects and one clinical case during static upright posture, chair rising–sitting, step up-and-down and level walking, and also during elementary flexion and extension... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4947942 Fri, 18 Mar 2011 00:00:00 +0100 4947942 http://www.medworm.com/index.php?rid=5032223&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000465%2Fabstract%3Frss%3Dyes Abstract: Background: Reconstruction of the anterior cruciate ligament is a standard surgical procedure in sports traumatology. The widespread replacement method using hamstring tendons has an important shortcoming namely delayed or missing bony healing in contrast to patellar tendon grafts where implant-free fixation is established by using the adjacent bone blocks. The purpose of this study was to describe a new implant-free surgical procedure using hamstring tendon grafts and to analyse the influence on tibiofemoral kinematics in vitro.Methods: Nine human knee specimens with arthroscopically transected anterior cruciate ligaments were mounted on a dynamic knee simulator and weight-bearing muscle-loaded knee flexions were simulated while a robotic universal force sensor system was used t... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5032223 Thu, 17 Mar 2011 00:00:00 +0100 5032223 http://www.medworm.com/index.php?rid=5032225&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000477%2Fabstract%3Frss%3Dyes Abstract: Background: The variability of peroneal reaction time measurements is a major problem when using this parameter to control rehabilitation or proprioceptive training processes. In order to control peroneal reaction time values, some extrinsic factors should be considered. The purpose of this study was to measure peroneal reaction time in unipodal stance for two different destabilization axes.Methods: The peroneal reaction time of 10 healthy subjects was measured from kinematic and electromyograhic data in an experimental study using an ankle destabilization device.Findings: In a preliminary analysis, results showed that the destabilization axis orientation did not affect peroneal reaction time values (68.5ms, standard deviation=9.5ms and 71.5ms, standard deviation=8ms for destabil... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5032225 Fri, 11 Mar 2011 00:00:00 +0100 5032225 http://www.medworm.com/index.php?rid=5032215&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000489%2Fabstract%3Frss%3Dyes This study investigated the influence of forward trunk inclination, spinal posture and pelvic fixation on maximum trunk rotation.Methods: Twenty male participants were assessed using an optoelectronic motion-analysis system to track trunk movement during maximal trunk rotations in different spinal positions within the sagittal plane. A repeated-measures multivariate analysis of variance investigated the effects of forward trunk inclination, spinal posture and pelvic fixation on trunk and pelvic rotation. Test–retest reliability was determined using interclass correlation coefficients and standard error of measurement.Findings: Forward trunk inclination at 45° yielded a 19% (6.2°; P (Source: Clinical Biomechanics) Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5032215 Fri, 11 Mar 2011 00:00:00 +0100 5032215 http://www.medworm.com/index.php?rid=4947950&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000362%2Fabstract%3Frss%3Dyes Abstract: Introduction: Arthrodesis is a well-established treatment option for end-stage osteoarthritis of the ankle. Osteoarthritis of the ankle can alter plantar pressure distribution. However, surprisingly little is known about the effect of ankle arthrodesis to alter plantar pressure distribution. The purpose of this study was to determine plantar pressure distribution in a selected group of patients with unilateral arthrodesis of the ankle joint.Methods: 20 patients with an average age of 60years who underwent isolated unilateral ankle arthrodesis using a 3-crossed screw technique by a single surgeon were included. After a mean of 25months (range 12–75months) post surgery plantar pressure distribution was determined in five regions of the foot. The outcome was evaluated clinically, ... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4947950 Fri, 11 Mar 2011 00:00:00 +0100 4947950 http://www.medworm.com/index.php?rid=5032226&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS026800331100060X%2Fabstract%3Frss%3Dyes This study aimed to: 1) examine the mechanical properties of the free human Achilles tendon in vivo by the use of ultrasonography and 2) assess the between-day reproducibility of these measurements.Methods: Ten male subjects had the Achilles tendon moment arm length, Achilles tendon cross sectional area and free Achilles tendon length determined. All subjects performed isometric plantarflexion ramp contractions to assess between-day reproducibility on two separate days. Simultaneous ultrasonography based measurements of Achilles-soleus myotendinous junction and Achilles-calcaneus osteotendinous junction displacement together with Achilles tendon force estimates yielded free Achilles tendon mechanical properties.Findings: Free Achilles tendon maximal force, deformation and stiffness were 19... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5032226 Thu, 10 Mar 2011 00:00:00 +0100 5032226 http://www.medworm.com/index.php?rid=5032220&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000611%2Fabstract%3Frss%3Dyes Abstract: Background: Hip and knee joint motion in the transverse and frontal plane during running may increase patellofemoral joint stress and contribute to the etiology of patellofemoral joint pain. We evaluated the association between these kinematics and the magnitude and timing of gluteus medius and maximus activity during running in females with patellofemoral pain. We also compared the magnitude and timing of gluteal muscle activity during running between females with and without patellofemoral pain.Methods: Twenty females with patellofemoral pain and twenty females without knee pain participated in this study. Three-dimensional running kinematics, gluteus medius and gluteus maximus onset time, activation duration, mean activation level, and peak activation level were recorded simul... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=5032220 Thu, 10 Mar 2011 00:00:00 +0100 5032220 http://www.medworm.com/index.php?rid=4947947&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000374%2Fabstract%3Frss%3Dyes Abstract: Background: Little is known about hip joint stiffness during walking (dynamic joint stiffness) and the effect of hip impairments on biomechanical alterations of other joints in patients with total hip arthroplasty.Methods: Twenty-four patients (mean age 61.7years) who underwent unilateral (n=12) or bilateral total hip arthroplasty (n=12) and healthy subjects (n=12) were recruited. In addition to kinematic and kinetic variables, dynamic hip joint stiffness which was calculated as an angular coefficient of linear regression of the plot of the hip flexion moment vs. hip extension angle during the late stance of gait, was measured. Group differences were compared using one-way ANOVA and Tukey's post-hoc test, and relationships between primary hip impairments and secondary gait impair... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4947947 Thu, 10 Mar 2011 00:00:00 +0100 4947947 http://www.medworm.com/index.php?rid=4947939&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000404%2Fabstract%3Frss%3Dyes Abstract: Background: Ageing is associated with geometrical changes in muscle fascicles that may lead to deteriorations in physical functions. The purpose of this study was to study the effects of ageing on fibre orientation and strength of the lumbar extensor muscles.Methods: Fifty two healthy, 26 younger (10 males and 16 females, aged from 20 to 35) and 26 older (10 males and 16 females, aged from 65 to 90) volunteers participated in this study. Ultrasound images of the lumbar extensor muscles were obtained with the participants in relaxed standing and half flexion (50% of the range of trunk flexion). The fibre angles at the mid-substance of the muscle were recorded. Lumbar extensor muscle strength was measured in the upright posture with a load cell.Findings: The mean lumbar extensor fi... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4947939 Thu, 10 Mar 2011 00:00:00 +0100 4947939 http://www.medworm.com/index.php?rid=4947951&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000416%2Fabstract%3Frss%3Dyes Abstract: Background: For the prevention of re-rupture during early healing phase, the primary repair strength of repaired lacerated tendons in hand surgery should be maximal and the reconstructed diameter minimal. Two new repair methods (small hook thread and internal splint) were assessed for strength and reconstructed diameter characteristics.Methods: Achilles tendons of 43 female New Zealand White rabbits were sectioned 2cm above the calcaneus. Specimens were divided into 7 groups and repaired as follows: Kirchmayr method 2-strand with 4.0 polypropylene thread; Becker method 4-strand; 6-strand; internal splint; Kirchmayr method small hook 2-strand; Becker method small hook 4-strand, non-modified tendon. Load until failure, load until gap formation, gap length, cross-sectional area and ... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4947951 Mon, 07 Mar 2011 00:00:00 +0100 4947951 http://www.medworm.com/index.php?rid=4947949&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000350%2Fabstract%3Frss%3Dyes Abstract: Backgrounds: Deficiencies in contemporary posterior crucitate retaining knee included inadequate femoral rollback and insufficient tibial rotation. Current study attempted to restore normal femoral rollback and tibial rotation to facilitate in knee flexion/extension and to achieve appropriate posture at deep knee bending after total knee arthroplasy by mimicking the morphology of convexly lateral tibial plateau of intact knee.Methods: Computational simulation was utilized to analyze motion of three-dimensional knee models, including intact, traditionally symmetrical posterior crucitate retaining and newly anatomic-like posterior crucitate retaining knees. Solid bones, attachments of ligaments and tendons of simulation models were reconstructed by magnetic resonance images of the ... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4947949 Mon, 07 Mar 2011 00:00:00 +0100 4947949 http://www.medworm.com/index.php?rid=4947938&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS026800331100043X%2Fabstract%3Frss%3Dyes This study helps to understand the in vivo behavior of the child trunk subjected to repetitive non-injurious mechanical loading. Further analysis in other populations and with different therapeutic maneuvers would refine the results. (Source: Clinical Biomechanics) Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4947938 Thu, 03 Mar 2011 00:00:00 +0100 4947938 http://www.medworm.com/index.php?rid=4584828&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000507%2Fabstract%3Frss%3Dyes (Source: Clinical Biomechanics) Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4584828 Tue, 01 Mar 2011 00:00:00 +0100 4584828 http://www.medworm.com/index.php?rid=4947952&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000258%2Fabstract%3Frss%3Dyes Abstract: Background: The mechanical characterization of trabecular bone is related to its structure. In order to describe the trabecular structure and to study the mechanical behavior of the trabecular tissue, several parameters are presented in the literature. Some studies suggest a possible dependence of the structure on bone volume fraction; this dependence could bias the validity of previous studies. The problem increases its complexity when pathological bone such as osteoarthritic tissue is studied, where the organization of the trabecular structure could be different if compared to the non-pathological tissue. The primary aim of this study was to evaluate the dependence between trabecular structure and bone volume fraction. The secondary aim was to compare osteoarthritic and non-pat... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4947952 Mon, 28 Feb 2011 00:00:00 +0100 4947952 http://www.medworm.com/index.php?rid=4647134&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000428%2Fabstract%3Frss%3Dyes The authors regret that the Young's modulus of the femoral stem used in the simulations in the original article was incorrectly given as 200GPa corresponding to CoCr. The correct stem material was Ti-alloy with E=110GPa. All simulations of the implanted femurs have been reanalyzed with the correct Young's modulus, and an updated Table 1 and Figs. 3, 4 and 5 are provided online as supplementary data to this corrigendum. (Source: Clinical Biomechanics) Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4647134 Mon, 28 Feb 2011 00:00:00 +0100 4647134 http://www.medworm.com/index.php?rid=4947941&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000234%2Fabstract%3Frss%3Dyes Abstract: Background: Iliac screw loosening has been a clinical problem in the lumbo-pelvic reconstruction. Although iliac screws are commonly inserted into either upper or lower iliac column, the biomechanical effects of the two fixations and their revision techniques with bone cement remain undetermined. The purpose of this study was to compare the anchoring strengths of the upper and lower iliac screws with and without cement augmentation.Methods: 5 pairs of formalin fixed cadaveric ilia with the bone mineral density values ranged from 0.82 to 0.97g/cm2 were adopted in this study. Using screws with 70-mm length and 7.5-mm diameter, 2 conventional iliac screw fixations and their revision techniques with cement augmentation were sequentially established and tested on the same ilium as fol... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4947941 Thu, 24 Feb 2011 00:00:00 +0100 4947941 http://www.medworm.com/index.php?rid=4772571&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000209%2Fabstract%3Frss%3Dyes This study quantified the acute biochemical responses to physical work stressing the low back and assessed the relationships between these systemic responses and specific lumbar spine tissue loads.Methods: Twelve healthy males were tested under control and two weight-lifting conditions (light and heavy). Venous blood was sampled at various time points before and after the physical work and analyzed for cytokine, granulocyte, and creatine kinase levels. Biomechanical data were collected during the tasks and a biologically-assisted lumbar spine model was used to calculate spinal loads at various lumbar spine levels and trunk muscle forces.Findings: Levels of interleukin-6, granulocytes, and creatine kinase all increased after both weight-lifting tasks, with the greatest changes observed with... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4772571 Thu, 24 Feb 2011 00:00:00 +0100 4772571 http://www.medworm.com/index.php?rid=4947946&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000349%2Fabstract%3Frss%3Dyes Abstract: Background: Flexible intramedullary nail fixation of dislocated diaphyseal femur fractures has gained wide acceptance for children and adolescents with open physes. Studies with a special emphasis on complications reveal frequent problems regarding stability, usually in complex fracture types such as spiral fractures and in older children weighing >40kg. This biomechanical study analyses how much the material of the nails influences the stiffness in a synthetic bone model.Methods: Twenty-four composite grafts (Sawbones®, 4th generation, medullar canal of 10mm) with an identical spiral fracture were used in three configurations of eight grafts. Elastic stable intramedullary nailing was performed in a retrograde C-shaped manner with two nails of equal size (2×3.5mm). Close contac... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4947946 Wed, 23 Feb 2011 00:00:00 +0100 4947946 http://www.medworm.com/index.php?rid=4772586&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000179%2Fabstract%3Frss%3Dyes Abstract: Background: The 2-strand side-locking loop technique allows secure locking formation easily, yielding maximum tensile force. However, not all suture materials are suitable for this technique.Methods: The bovine gastrocnemius tendons were transected and repaired end-to-end by the side-locking loop technique using USP2 braided polyblend, braided polyester, monofilament nylon, braided nylon, or monofilament absorbable polydioxanone sutures. A repetitive loading protocol from 10N to 100N was used, and the loading was repeated 10,000 times. In ruptured samples during the repetitive loading test, the number of loading was recorded. In samples which did not rupture, the ultimate tensile strength was measured after repetitive loading. After testing, ruptured sutures were examined microsc... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4772586 Tue, 22 Feb 2011 00:00:00 +0100 4772586 http://www.medworm.com/index.php?rid=4947945&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000246%2Fabstract%3Frss%3Dyes This study addresses the risk of femoral neck fracture associated with resurfacing hip prostheses. A novel cemented Proximal Epiphyseal Replacement (PER) featuring a short curved stem was investigated.Methods: Seven pairs of femurs were in vitro tested. One femur of each pair was randomly assigned for PER implantation. The contralateral femur was tested intact. All femurs were loaded to failure in a validated, physiological configuration. High-speed videos (10,000–12,000 frames/s) were acquired to identify the location of fracture initiation. For comparison, data were included from Birmingham Hip Resurfacing previously tested in an identical fashion (N=3).Findings: Relative to the contralateral intact femurs, the failure load of the PER and Birmingham implants was 15.4% higher and 10.0% ... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4947945 Mon, 21 Feb 2011 00:00:00 +0100 4947945 http://www.medworm.com/index.php?rid=4947940&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000337%2Fabstract%3Frss%3Dyes The objective of this study is to develop a biomechanical model for the spine instrumentation with the DIST system in order to simulate, analyze and compare different deformity correction strategies.Methods: The patient-specific spine geometry was reconstructed using calibrated coronal and sagittal radiographs. The spine biomechanical properties were adapted from experimental data and further adjusted using the patient's side-bending radiographs. Instrumentation constructs were modeled as rigid bodies connected by kinematic joints. The instrumentation maneuvers of 6 cases were simulated for which the simulation parameters were extracted from the surgery documentation and video. The correction maneuvers and resulting effects were analyzed.Findings: The simulations agreed well with the real ... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4947940 Mon, 21 Feb 2011 00:00:00 +0100 4947940 http://www.medworm.com/index.php?rid=4772581&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000180%2Fabstract%3Frss%3Dyes This study investigated the effects of bracing on the kinematics and kinetics of involved and contralateral joints during gait.Methods: Nineteen patients with medial compartment knee osteoarthritis were analysed. Kinematics and kinetics of the knee and hip joints in frontal and sagittal planes were measured during walking without and with bracing on the more symptomatic knee.Findings: The ipsilateral hip in the braced condition showed a lower adduction angle by an average of 2.58° (range, 1.05°–4.16°) during 1%–49% of the stance phase, and a lower abduction moment at the second peak during the stance phase than the hip in the unbraced condition (P (Source: Clinical Biomechanics) Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4772581 Thu, 17 Feb 2011 00:00:00 +0100 4772581 http://www.medworm.com/index.php?rid=4772574&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000210%2Fabstract%3Frss%3Dyes This study focuses on the relationship between overuse in association with wheelchair activities of daily living and risks for osteoarthrosis in the acromioclavicular and sternoclavicular joints. The aim is to quantify the joint moments and joint reaction forces in all three joints of the shoulder complex during wheelchair-related activities of daily living.Methods: A convenience sample of 17 subjects performed two tasks (wheelchair propulsion and weight relief lifting). Three-dimensional kinematics and kinetics were measured and position and force data were used as input for a musculoskeletal model of the arm and shoulder. Output variables of the model were the moments and the joint reaction forces on the sternoclavicular, acromioclavicular and glenohumeral joints.Findings: Moments on the... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4772574 Mon, 14 Feb 2011 00:00:00 +0100 4772574 http://www.medworm.com/index.php?rid=4772573&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000027%2Fabstract%3Frss%3Dyes Abstract: Background: Fusionless scoliosis surgery is an early-stage treatment for idiopathic scoliosis which claims potential advantages over current fusion-based surgical procedures. Anterior vertebral stapling using a shape memory alloy staple is one such approach. Despite increasing interest in this technique, little is known about the effects on the spine following insertion, or the mechanism of action of the staple. The purpose of this study was to investigate the biomechanical consequences of staple insertion in the anterior thoracic spine, using in vitro experiments on an immature bovine model.Methods: Individual calf spine thoracic motion segments were tested in flexion, extension, lateral bending and axial rotation. Changes in motion segment rotational stiffness following staple ... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4772573 Mon, 14 Feb 2011 00:00:00 +0100 4772573 http://www.medworm.com/index.php?rid=4772582&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000192%2Fabstract%3Frss%3Dyes Abstract: Background: Impulsive frontal plane knee joint torques directly strain the anterior cruciate ligament and therefore may contribute to injury risk. Because deleterious torques may in part be related to aberrant kinematic movement patterns the primary purpose of this study was to establish a prediction model for frontal plane knee joint torques based on motion characteristics derived from Principal Component Analysis.Methods: Eighteen healthy NCAA Division I female athletes performed a single-leg land-and-cut maneuver (n=5 trials) with their dominant limb. Ensemble average lower extremity joint angles for the hip, knee, and ankle along with normalized external knee abduction torques were calculated for the entire stance phase. The ensemble kinematic data were individually submitted... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4772582 Wed, 09 Feb 2011 00:00:00 +0100 4772582 http://www.medworm.com/index.php?rid=4467180&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003311000040%2Fabstract%3Frss%3Dyes (Source: Clinical Biomechanics) Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4467180 Tue, 01 Feb 2011 00:00:00 +0100 4467180 http://www.medworm.com/index.php?rid=4772585&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003310003414%2Fabstract%3Frss%3Dyes Abstract: Background: Insufficient and excessive stiffness may increase the risk of soft tissue and bone injuries, respectively, while the resonance frequency seems to be related with energy expenditure and stiffness. With aging and menopause muscle weakness, physical fragility and mobility limitations are also expected. Therefore this study addresses the differences of biomechanical properties of the triceps surae muscle–tendon unit between young and postmenopausal women.Methods: 39 young and 37 postmenopausal women participated. The biomechanical properties of the triceps surae muscle–tendon unit were assessed in vivo using a free oscillation technique involving 30% of the maximal voluntary isometric contraction load.Findings: The postmenopausal women in this study show significant h... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4772585 Mon, 31 Jan 2011 00:00:00 +0100 4772585 http://www.medworm.com/index.php?rid=4772580&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003310003372%2Fabstract%3Frss%3Dyes The objective of this study was to develop a realistic biomechanical model with which to compare superior with inferior-medial plate placement, and the failure resistance of locked and against non-locked constructs.Methods: We estimated implant loads for operated patients in early rehabilitation utilising 3-D mathematical model of the shoulder. During simulation of upper limb motion associated with eating, the fracture opened in an inferior and frontal direction. The peak X, Y, and Z loads from the simulation were reproduced using a materials testing machine. A one centimetre transverse osteectomy was created at the midshaft of forty composite clavicles. Each specimen was then fixed with either (1) non-locked superior plating (n=10), (2) locked superior plating (n=10), (3) non-locked infer... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4772580 Mon, 24 Jan 2011 00:00:00 +0100 4772580 http://www.medworm.com/index.php?rid=4772583&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003310003402%2Fabstract%3Frss%3Dyes Abstract: Background: Persons with post-stroke hemiparesis usually walk slowly and asymmetrically. Stroke severity and functional walking status are commonly predicted by post-stroke walking speed. The mechanisms that limit walking speed, and by extension functional walking status, need to be understood to improve post-stroke rehabilitation methods.Methods: Three-dimensional forward dynamics walking simulations of hemiparetic subjects (and speed-matched controls) with different levels of functional walking status were developed to investigate the relationships between muscle contributions to walking subtasks and functional walking status. Muscle contributions to forward propulsion, swing initiation and power generation were analyzed during the pre-swing phase of the gait cycle and compared... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4772583 Fri, 21 Jan 2011 00:00:00 +0100 4772583 http://www.medworm.com/index.php?rid=4772576&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003310003396%2Fabstract%3Frss%3Dyes Abstract: The purpose of this study was to test femur strength and the ability to prevent fracture displacement of two minimal invasive Elastomer femoroplasty techniques.Methods: A total of sixteen fixed human cadaveric femur pairs were used. From each pair one femur was randomly assigned for Elastomer femoroplasty. In these femora we drilled a 3.5mm entrance in the lateral cortex. Cavities for the Elastomer were created by: group A, balloon and group B an excentric drill. All femora were fractured by simulating a fall on the greater trochanter. Neck-shaft-angles on plain anterior posterior radiographs were measured to determine fracture displacement.Findings: There was no significant difference in fracture load between controls and treated femora for group A, 2904N (SD 1091) versus 2803N ... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4772576 Fri, 21 Jan 2011 00:00:00 +0100 4772576 http://www.medworm.com/index.php?rid=4772572&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003310003426%2Fabstract%3Frss%3Dyes The objective of this study was to determine the effects of creep and recovery on the range of motion, neutral zone, and neutral zone stiffness of thoracolumbar multi-level spinal segments in flexion, extension, lateral bending and axial rotation.Methods: Six human cadaveric spines (age at time of death 55–84years) were sectioned in T1–T4, T5–T8, T9–T12, and L1–L4 segments and prepared for testing. Moments were applied of +4 to −4Nm in flexion-extension, lateral bending, and axial rotation. This was repeated after 30min of creep loading at 2Nm in the tested direction and after 30min of recovery. Displacement of individual motion segments was measured using a 3D optical movement registration system. The range of motion, neutral zone, and neutral zone stiffness of the middle moti... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4772572 Fri, 21 Jan 2011 00:00:00 +0100 4772572 http://www.medworm.com/index.php?rid=4647120&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS026800331000313X%2Fabstract%3Frss%3Dyes Abstract: Background: To study normal or pathological neuromuscular control, a musculoskeletal model of the neck has great potential but a complete and consistent anatomical dataset which comprises the muscle geometry parameters to construct such a model is not yet available.Methods: A dissection experiment was performed on the left side of one 50th percentile male embalmed specimen. Geometrical data including muscle attachment sites were digitized using an Optotrak measurement system and laser diffraction was used to determine muscle sarcomere lengths. Bony landmarks were recorded and joint centres of rotation between different vertebrae were estimated using literature data.Findings: A total of 34 muscle parts of the neck were divided in 129 elements per body side. Muscle attachment sites... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4647120 Thu, 20 Jan 2011 00:00:00 +0100 4647120 http://www.medworm.com/index.php?rid=4647117&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003310003049%2Fabstract%3Frss%3Dyes Abstract: This paper introduces control concepts that are important for ensuring stability. To clarify these concepts, a series of experiments using a simple task of stick balancing will be performed. The lessons from these experiments will be applied to the spine system and illustrated with clinical examples. Insight into the following will be gained: what information is used to stabilize the spine, how does noise in control affect spine performance, how has the spine evolved to allow it to be stabilized and controlled in a metabolically efficient way, how do delays in control affect spine performance, and how do different goals (i.e., maximizing performance versus minimizing fatigue) affect the logic for controlling the spine? (Source: Clinical Biomechanics) Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4647117 Wed, 19 Jan 2011 00:00:00 +0100 4647117 http://www.medworm.com/index.php?rid=4647130&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003310003323%2Fabstract%3Frss%3Dyes Abstract: Background: Osteosynthesis implants, which remain in the patient after fracture union to save additional surgery, may affect the strain distribution within the bone. A reduction of strain within the bone is known to result in localized bone loss (“stress shielding”) and increased fracture risk. The purpose of this study was to examine whether extramedullary fixations for femoral neck fractures have to be removed after fracture union to prevent reductions in cortex strains.Methods: In a biomechanical experiment, six pairs of human cadaver femora (mean age 56years, range 48 to 64) were supplied with five strain gauges per bone. The bones were equally supplied with a compression hip screw or a femoral neck plate. Before surgery, after surgery and after removal of the implants, a... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4647130 Tue, 18 Jan 2011 00:00:00 +0100 4647130 http://www.medworm.com/index.php?rid=4647133&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003310003104%2Fabstract%3Frss%3Dyes Abstract: Background: Although impaired balance control during quiet standing has repeatedly been reported in persons suffering from foot pain, a better understanding of the effect of foot pain on unperturbed postural control is needed in order to propose and implement efficient podiatry treatments/interventions into clinical practice. The present study was hence designed to address this issue.Methods: Ten young healthy adults were asked to stand upright, eyes closed, as still as possible in three experimental conditions: (1) a no-pain condition, (2) a condition when a painful stimulation was applied to the plantar surfaces of both feet, and (3) a condition in which painful stimulation was applied to another body part, the palms of both hands. The centre of foot pressure displacements was ... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4647133 Fri, 14 Jan 2011 00:00:00 +0100 4647133 http://www.medworm.com/index.php?rid=4772579&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003310003359%2Fabstract%3Frss%3Dyes Abstract: Background: Elevation of a locking plate over the bone surface not only supports biological fixation, but also decreases the torsional strength of the fixation construct. Biplanar fixation by means of a staggered screw hole arrangement may combat this decreased torsional strength caused by plate elevation. This biomechanical study evaluated the effect of biplanar fixation on the torsional strength of locking plate fixation in the femoral diaphysis.Methods: Custom titanium plates were manufactured with either a linear or staggered hole pattern to evaluate planar and biplanar fixation, respectively. Fixation strength under torsional loading was evaluated in surrogates of the femoral diaphysis representative of osteoporotic and non-osteoporotic bone. Furthermore, fixation strength w... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4772579 Mon, 10 Jan 2011 00:00:00 +0100 4772579 http://www.medworm.com/index.php?rid=4647132&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003310003360%2Fabstract%3Frss%3Dyes Abstract: Background: Deep fresh freezing is the most commonly used preservation method for allografts, which is followed by a routine procedure before application—the thawing of the grafts. This work was to explore the biomechanics effects of repetitive freezing–thawing on human tendons.Methods: Thirty tendons (flexor digitorum superficialis and flexor pollicis longus tendons) were taken from three fresh cadavers. We assigned these tendons into six groups randomly. After the preparation and measurement of cross-sectional area, Fresh Group was tested immediately. The remaining five groups, before biomechanical testing, underwent multiple cycles (1, 2, 3, 5 or 10cycles) of freezing (−80°C for 4days) and thawing (room temperature for 6h). Using a material-testing machine, we performed... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4647132 Mon, 10 Jan 2011 00:00:00 +0100 4647132 http://www.medworm.com/index.php?rid=4647121&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003310003165%2Fabstract%3Frss%3Dyes Abstract: Background: Shoulder impingement syndrome is a common upper extremity pathology in manual wheelchair users. Central to impingement is the orientation of the scapula and humerus as they determine the available subacromial space. The purpose of this study was to examine the scapulothoracic and glenohumeral internal/external rotation kinematics during the time of peak shoulder loading of propulsion and weight relief lift conditions to assess possible risk of impingement.Methods: Scapula, humerus and trunk kinematics were measured for twelve manual wheelchair users over three conditions: level propulsion, ramp propulsion, and a weight relief lift. Scapulothoracic and glenohumeral kinematic variables were characterized for the full cycle of each condition as well as at the period of p... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4647121 Mon, 10 Jan 2011 00:00:00 +0100 4647121 http://www.medworm.com/index.php?rid=4467181&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003310003384%2Fabstract%3Frss%3Dyes In this study, the methods for virtually reconstructing a tibial plafond fracture were developed and applied to clinical cases. Building upon previous benchtop work, novel image analysis techniques and puzzle solving algorithms were developed for clinical application. Specialty image analysis tools were used to segment the fracture fragment geometries from CT data. The original anatomy was then restored by matching fragment native (periosteal and subchondral) bone surfaces to an intact template, generated from the uninjured contralateral limb.Findings: Virtual reconstructions obtained for ten tibial plafond fracture cases had average alignment errors of 0.39 (0.5 standard deviation) mm. In addition to precise reduction planning, 3D puzzle solutions can help identify articular deformities a... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4467181 Mon, 10 Jan 2011 00:00:00 +0100 4467181 http://www.medworm.com/index.php?rid=4772584&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003310003335%2Fabstract%3Frss%3Dyes The objective of this study was to investigate changes in active and passive biomechanical properties of the calf muscle–tendon unit induced by controlled ankle stretching in stroke survivors.Methods: Ten stroke survivors with ankle spasticity/contracture and ten healthy control subjects received intervention of 60-min ankle stretching. Joint biomechanical properties including resistance torque, stiffness and index of hysteresis were evaluated pre- and post-intervention. Achilles tendon length was measured using ultrasonography. The force output of the triceps surae muscles was characterized via the torque–angle relationship, by stimulating the calf muscles at a controlled intensity across different ankle positions.Findings: Compared to healthy controls, the ankle position correspondin... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4772584 Fri, 07 Jan 2011 00:00:00 +0100 4772584 http://www.medworm.com/index.php?rid=4647131&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003310003086%2Fabstract%3Frss%3Dyes This study compared the maximum load, stress, elongation at failure and the mode of failure of three kinds of tendons most frequently used for tendon grafting and tendon transfers, using the Pulvertaft weave suture.Methods: Sixty tendons were used from fresh human cadaver upper and lower extremities. The performed repairs included: 9 specimens of flexor digitorum superficialis or profundus tendon with flexor digitorum superficialis or profundus tendon (thick–thick suture), 10 specimens of flexor digitorum superficialis or profundus tendon with palmaris longus tendon (thick–medium thin suture), and 10 specimens of flexor digitorum superficialis or profundus tendon with plantaris tendon (thick–thin suture).Material testing machine was used to test repairs to failure.Findings: The mean ... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4647131 Fri, 07 Jan 2011 00:00:00 +0100 4647131 http://www.medworm.com/index.php?rid=4772577&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003310003347%2Fabstract%3Frss%3Dyes Abstract: Background: A Sit to Stand task following a hip fracture may be achieved through compensations (e.g. bilateral arms and uninvolved lower extremity), not restoration of movement strategies of the involved lower extremity. The primary purpose was to compare upper and lower extremity movement strategies using the vertical ground reaction force during a Sit to Stand task in participants recovering from a hip fracture to control participants. The secondary purpose was to evaluate the correlation between vertical ground reaction force variables and validated functional measures.Methods: Twenty eight community dwelling older adults, 14 who had a hip fracture and 14 control participants completed the Sit to Stand task on an instrumented chair designed to measure vertical ground reaction ... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4772577 Mon, 03 Jan 2011 00:00:00 +0100 4772577 http://www.medworm.com/index.php?rid=4647123&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003310003153%2Fabstract%3Frss%3Dyes This study evaluated the efficacy of progressive resistance, whole body, long-axis rotational training to improve lower extremity neuromuscular control during a single leg lateral drop landing and stabilization.Methods: Thirty-six healthy subjects were randomly assigned to either Training or Control groups. Electromyographic, ground reaction force, and kinematic data were collected from three pre-test, post-test trials. Independent sample t-tests with Bonferroni corrections for multiple comparisons were used to compare group mean change differences (P≤0.05/21≤0.0023).Findings: Training group gluteus maximus and gluteus medius neuromuscular efficiency improved 35.7% and 31.7%, respectively. Training group composite vertical–anteroposterior–mediolateral ground reaction force stabiliz... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4647123 Mon, 03 Jan 2011 00:00:00 +0100 4647123 http://www.medworm.com/index.php?rid=4365406&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003310003219%2Fabstract%3Frss%3Dyes (Source: Clinical Biomechanics) Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4365406 Sat, 01 Jan 2011 00:00:00 +0100 4365406 http://www.medworm.com/index.php?rid=4647129&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003310003141%2Fabstract%3Frss%3Dyes Abstract: Background: It is hypothesized that the working length influences the implants fatigue behavior. However, few studies addressing this issue came to contrary results. Therefore, we tested systematically the influence of working length and implant material on the plate's endurance.Methods: We used an artificial model providing the substantial angle and length conditions of a human femur. A fracture gap of 10mm was bridged with identical shaped plate implants made of stainless steel and grade-2 titanium. The fatigue strength was tested for a short, medium and long working length. Aiming at an implant failure within 80,000 loading cycles the upper load threshold was set to 265N for the titanium plates and to 420N for the steel plates. The lower load threshold was −20N for both plat... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4647129 Mon, 27 Dec 2010 00:00:00 +0100 4647129 http://www.medworm.com/index.php?rid=4647125&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003310003128%2Fabstract%3Frss%3Dyes This study investigated lower extremity electromyograms during walking in asymptomatic individuals and individuals with different severities of knee osteoarthritis who walked with similar self-selected velocities.Methods: Muscle activity in lateral and medial gastrocnemius, vastus lateralis and medialis, rectus femoris and the lateral and medial hamstrings was monitored during self-selected walking in 230 subjects with asymptomatic knees, moderate and severe knee osteoarthritis. Sixteen asymptomatic individuals, 16 individuals with moderate and 15 individuals with severe knee osteoarthritis were identified based on similarities in average walking velocity. Principal component analysis was employed to derive amplitude and temporal characteristics of the electromyographic (EMG) waveforms. An... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4647125 Mon, 27 Dec 2010 00:00:00 +0100 4647125 http://www.medworm.com/index.php?rid=4647118&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003310003116%2Fabstract%3Frss%3Dyes Abstract: Background: Stature loss is a commonly used measure of spinal load. The aim of this study was to investigate the pattern of diurnal stature change in those with and without chronic low-back pain, over a 24-h period.Methods: Eight participants with chronic low-back pain (age 24.6 (SD 4.3) years, height 1.76 (SD 0.08) m, body mass 72.8 (SD 11.1) kg) and eight controls (age 21.8 (SD 2.0) years, height 1.75 (SD 0.10) m, body mass 71.8 (SD 11.6) kg) participated in this investigation. Twenty-four stature measurements were performed over a 24-h period.Findings: The trough to peak variation in stature of 17.9mm (low-back pain group) and 17.6mm (control group) did not differ between groups (P>0.05). Both groups experienced greatest stature change in the 1st hour after rising (31.3% [low-... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4647118 Fri, 24 Dec 2010 00:00:00 +0100 4647118 http://www.medworm.com/index.php?rid=4647127&cid=s_35400_31_f&fid=35400&url=http%3A%2F%2Fwww.clinbiomech.com%2Farticle%2FPIIS0268003310003098%2Fabstract%3Frss%3Dyes Abstract: Background: A greater Q-angle has been suggested as a risk factor for Patellofemoral Pain Syndrome. Greater frontal plane knee moment and impulse have been found to play a functional role in the onset of Patellofemoral Pain Syndrome in a running population. Therefore, the purpose of this investigation was to determine the relationship between Q-angle and the magnitude of knee abduction moment and impulse during running.Methods: Q-angle was statically measured, using a goniometer from three markers on the anterior superior iliac spine, the midpoint of the patella and the tibial tuberosity. Thirty-one recreational runners (21 males and 10 females) performed 8–10 trials running at 4m/s (SD 0.2) on a 30m-runway. Absolute and normalized knee moment and impulse were calculated and co... Clinical Biomechanics journals http://www.medworm.com/rss/comments.php?id=4647127 Wed, 22 Dec 2010 00:00:00 +0100 4647127