Journal of Orthopaedic Research via MedWorm.com

Musculoskeletal deformities secondary to neurotomy of the superior trunk of the brachial plexus in neonatal mice

Journal of Orthopaedic Research — Fri, 12 Mar 2010 00:00:00 +0100

The developmental course of musculoskeletal deformities in neonatal brachial plexus palsy (NBPP) has not been studied extensively. The goals of this study were to: (1) evaluate a new animal model of NBPP, (2) characterize the development of musculoskeletal abnormalities in paralyzed shoulders, and (3) investigate the expression of myogenic and adipogenic genes in paralyzed rotator cuff muscles. Neonatal mice were divided into neurotomy and sham groups. The neurotomy group underwent surgical transection of the superior trunk of the brachial plexus within 24 h of birth. The sham group underwent the same surgical exposure, but the brachial plexus was left intact. Musculoskeletal deformities were evaluated with radiological and histological assays at 2, 4, 8, 12, and 30 weeks after birth. The ...

Correlations between effective permeability and marrow contact channels surface of vertebral endplates

Journal of Orthopaedic Research — Thu, 11 Mar 2010 00:00:00 +0100

Homeostasis of the intervertebral disc relies on nutrient supply and waste clearance through the dense capillary network that is in contact with the cartilage endplate (CEP). We developed a micro-computerized tomography (micro-CT) method to quantify the marrow contact channel surface (MCCS) with the CEP and to validate the hypothesis according to which MCCS was correlated to the effective permeability of the vertebral endplate (VEP) and influenced by the mechanical stimuli. The influence of compression loading on local vascularization was investigated. Six 4-week-old skeletally immature pigs were instrumented with left pedicle screws and rod at both T5-T6 and L1-L2 levels to create asymmetrical spine tethers. After 3 months of growth, three cylindrical specimens of the VEP (one central and...

Individual susceptibility to periprosthetic osteolysis is associated with altered patterns of innate immune gene expression in response to pro-inflammatory stimuli

Journal of Orthopaedic Research — Thu, 11 Mar 2010 00:00:00 +0100

We examined whether patients susceptible to osteolysis (group I, n = 34 subjects) after cemented Charnley THA have quantitatively different innate immune responses to pro-inflammatory stimuli versus patients without this susceptibility (group II, n = 28 subjects) at a mean of 14 years after primary surgery. Extracted peripheral blood mononuclear cells were stimulated for 3 h using endotoxin (lipopolysaccharide - LPS, 100 ng/mL), endotoxin-stripped titanium particles (Ti) or endotoxin-stripped particles with adherent LPS added-back (TI + LPS). Subjects returned 1 week later and the experimental protocol was repeated. Assays for mRNA induction for interleukin (IL)-1[alpha], IL-1[beta], IL-1Ra, IL-6, IL-10, IL-18, and tumor necrosis factor (TNF) were made using quantitative real-time PCR. Alt...

Cross-linking affects cellular condensation and chondrogenesis in type II collagen-GAG scaffolds seeded with bone marrow-derived mesenchymal stem cells

Journal of Orthopaedic Research — Thu, 11 Mar 2010 00:00:00 +0100

The objective of this study was to investigate the association of aggregation (condensation) of mesenchymal stem cell (MSCs) and chondrogenesis in vitro. Previous work with chondrocytes indicated that the cross-link density and related cell-mediated contraction of collagen scaffolds significantly affects cartilaginous tissue formation within the cell-seeded construct. Based on this finding, we hypothesized that the cell-aggregating effect of the contraction of MSC-seeded collagen scaffolds of lower cross-link density favors chondrogenesis; scaffolds of higher cross-link density, which resist cell-mediated contraction, would demonstrate a lower cell number density (i.e., subcritical packing density) and less cartilage formation. Type II collagen-GAG scaffolds, chemically cross-linked to ach...

Pentadecapeptide BPC 157 (PL 14736) improves ligament healing in the rat

Journal of Orthopaedic Research — Thu, 11 Mar 2010 00:00:00 +0100

We improved medial collateral ligament (MCL) healing throughout 90 days after surgical transection. We introduced intraperitoneal, per-oral (in drinking water) and topical (thin cream layer) peptide therapy always given alone, without a carrier. Previously, as an effective peptide therapy, stable gastric pentadecapeptide BPC 157 (GEPPPGKPADDAGLV, an anti-ulcer peptide effective in inflammatory bowel disease therapy (PL 14736)) particularly improved healing of transected tendon and muscle and wound healing effect including the expression of the early growth response 1 (egr-1) gene. After MCL transection BPC 157 was effective in rats when given once daily intraperitoneally (10 µg or 10 ng/kg) or locally as a thin layer (1.0 µg dissolved in distilled water/g commercial neutral cream) at the...

Effect of nicotine and tobacco administration method on the mechanical properties of healing bone following closed fracture

Journal of Orthopaedic Research — Thu, 11 Mar 2010 00:00:00 +0100

We previously showed different effects of tobacco and nicotine on fracture healing, but due to pump reservoir limits, maximum exposure period was 4 weeks. To allow flexibility in pre- and post-fracture exposure periods, the objective of this study was to compare a new oral administration route for nicotine to the established pump method. Four groups were studied: (1) pump saline, (2) pump saline + oral tobacco, (3) pump saline/nicotine + oral tobacco, and (4) pump saline + oral nicotine/tobacco. Sprague-Dawley rats (n = 84) received a transverse femoral fracture stabilized with an intramedullary pin 1 week after initiating dosing. After 3 weeks, no difference was found in torsional strength or stiffness between oral nicotine/tobacco or pump nicotine + tobacco, while energy absorption with ...

Age-associated increases in the size of the infrapatellar fat pad in knee osteoarthritis as measured by 3T MRI

Journal of Orthopaedic Research — Thu, 11 Mar 2010 00:00:00 +0100

This study examined the hypotheses that the volume of the infrapatellar fat pad is correlated to the body mass index (BMI) of OA patients, and that fat pad volume is greater in subjects with OA. Fat pad volume was measured in sequential magnetic resonance (MR) images taken over one year in a cohort of 15 control and 15 knee OA subjects. No differences were observed in the fat pad volume between the two groups at baseline, 3, 6, or 12 months. In control subjects, no significant correlations were present between any parameters (age, BMI, weight, volume of fat pad at any time point). However, in the osteoarthritic group, fat pad volume was correlated with age at every time point. One possible explanation is that local factors related to knee OA may also induce enlargement of the fat pad with ...

Mouse treadmill running enhances tendons by expanding the pool of tendon stem cells (TSCs) and TSC-related cellular production of collagen

Journal of Orthopaedic Research — Thu, 11 Mar 2010 00:00:00 +0100

This study aims to explore these mechanisms by using a mouse treadmill running model to examine the effects of exercise on newly discovered tendon stem cells (TSCs). After treadmill running, patellar TSCs (PTSCs) and Achilles TSCs (ATSCs) were isolated from the mice, and their proliferation was measured in vitro. We found that treadmill running nearly doubled proliferation rates of both PTSCs and ATSCs compared to cage control mice. Moreover, using a mixed tendon cell culture consisting of TSCs and tenocytes, cellular production of collagen was found to increase by 70% and 200% in PTSCs and ATSCs, respectively, from the treadmill running group over cells from the cage control group. These findings suggest that exercise exerts its anabolic effects on tendons at least in part by increasing p...

Diminished cartilage creep properties and increased trabecular bone density following a single, sub-fracture impact of the rabbit femoral condyle

Journal of Orthopaedic Research — Thu, 11 Mar 2010 00:00:00 +0100

Traumatic injury to articular cartilage can lead to post-traumatic arthritis. We used a custom pendulum device to deliver a single, near-fracture impact to the medial femoral condyles of rabbits. Impact was localized to a region [sim]3 mm in diameter, and impact stress averaged [sim]100 MPa. Animals were euthanized at 0, 1, and 6 months after impact. Cartilage mechanical properties from impacted and sham knees were evaluated by creep-indentation testing, and periarticular trabecular bone was evaluated by microCT and histomorphometry. Impact caused immediate and statistically significant loss of cartilage thickness (-40% vs. sham) and led to a greater than twofold increase in creep strain. From 0 to 6 months after impact, the ability of cartilage to recover from creep deformation became sig...

Bone deposition, bone resorption, and osteosarcoma

Journal of Orthopaedic Research — Thu, 11 Mar 2010 00:00:00 +0100

Bone deposition and bone resorption are ongoing dynamic processes, constituting bone remodeling. Some bone tumors, such as osteosarcoma (OS), stimulate focal bone deposition. OS is the most common primary bone tumor in children and young adults. A complex network of genes regulates bone remodeling and alterations in its expression levels can influence the genesis and progression of bone diseases, including OS. We hypothesized that the expression profiles of bone remodeling regulator genes would be correlated with OS biology and clinical features. We used real-time PCR to evaluate the mRNA levels of the tartrate-resistant acid phosphatase (ACP5), colony stimulating factor-1 (CSF1R), bone morphogenetic protein 7 (BMP7), collagen, type XI, alpha 2 (COL11A2), and protein tyrosine phosphatases ...

Median nerve deformation and displacement in the carpal tunnel during index finger and thumb motion

Journal of Orthopaedic Research — Thu, 11 Mar 2010 00:00:00 +0100

The purpose of this study was to investigate the deformation and displacement of the normal median nerve in the carpal tunnel during index finger and thumb motion, using ultrasound. Thirty wrists from 15 asymptomatic volunteers were evaluated. Cross-sectional images during motion from full extension to flexion of the index finger and thumb were recorded. On the initial and final frames, the median nerve, flexor pollicis longus (FPL), and index finger flexor digitorum superficialis (FDS) tendons were outlined. Coordinate data were recorded and median nerve cross-sectional area, perimeter, aspect ratio of the minimal-enclosing rectangle, and circularity in extension and flexion positions were calculated. During index finger flexion, the tendon moves volarly while the nerve moves radially. Wi...

Changes in chondrogenic phenotype and gene expression profiles associated with the in vitro expansion of human synovium-derived cells

Journal of Orthopaedic Research — Thu, 11 Mar 2010 00:00:00 +0100

We undertook this study to characterize changes in the proliferative capacities, chondrogenic phenotypes, and gene expression profiles of human synovium-derived progenitor cells from osteoarthritic patients during in vitro expansion. Cells isolated from osteoarthritic synovia were cultured, and growth rates during serial passages were evaluated. Surface molecule expressions were determined by flow cytometry and cytogenetic analyses were performed. After chondrogenic differentiation in cell pellets, we evaluated type II collagen and glycosaminoglycan (GAG) synthesis. To assess whether the in vitro expansion of synovium-derived cells affects gene expression, we performed microarray analyses on cells at passage 0, 1, 2, 4, 6, and 8. Synovium-derived cells were rapidly expanded in vitro throug...

Antiapoptotic effects of anthocyanins on rotator cuff tenofibroblasts

Journal of Orthopaedic Research — Wed, 10 Mar 2010 00:00:00 +0100

Degeneration of the rotator cuff tendon, which involves apoptosis of the tenofibroblasts, is one of the most common shoulder problems that can lead eventually to a full-thickness rotator cuff tendon tear. The current authors evaluated both the ability of anthocyanins, which are powerful antioxidants, to reduce apoptosis in oxidation-stressed rotator cuff tenofibroblasts, and the molecular mechanism for this antiapoptotic action. Anthocyanins demonstrated a dose-dependent ability to inhibit H2O2-induced apoptosis in cultured tenofibroblasts, as assessed by MTT assay and FACS analysis. H2O2 increased the phosphorylation of extracellular regulated kinase1/2 (ERK1/2) and of c-Jun N-terminal kinase (JNK) and the production of reactive oxygen species (ROS). In contrast, treatment with anthocyani...

The effect of femoral component rotation on the extensor retinaculum of the knee

Journal of Orthopaedic Research — Tue, 09 Mar 2010 00:00:00 +0100

Malrotation of the femoral component may cause patellofemoral complications after total knee replacement (TKR). We hypothesized that femoral component malrotation would cause excessive lengthening of the retinacula. Retinacular length changes were measured by threading fine sutures along them and attaching these to the patella and to displacement transducers. The knee post-TKR was flexed-extended while the quadriceps were tensed, then the measurements repeated after rotating the femoral component 5° internally and then 5° externally. Internal rotation shortened the medial patellofemoral ligament (MPFL) significantly from 100° to 0° extension. External rotation lengthened the MPFL significantly from 90° to 0° extension. The transverse fibers of the lateral retinaculum showed no signif...

In vivo anabolic effect of strontium on trabecular bone was associated with increased osteoblastogenesis of bone marrow stromal cells

Journal of Orthopaedic Research — Mon, 01 Mar 2010 00:00:00 +0100

In vitro studies have demonstrated that strontium (Sr) could increase osteogenic differentiation of bone marrow stromal cells (BMSCs). We investigated the in vivo effect of Sr on BMSCs. Thirty-six female rats were randomly divided into the following groups: sham operated and treated with either vehicle (Sham + Veh) or Sr compound (Sham + Sr) and ovariectomized and treated with either vehicle (OVX + Veh) or Sr compound (OVX + Sr). Vehicle and Sr were orally administrated daily starting immediately after the surgery and continuing for 12 weeks. The anabolic effect of Sr on trabecular bone was determined at the structural and tissue level by microCT and histomorphometry, respectively. Colony formation assays demonstrated that BMSCs exhibited higher osteogenic colony but lower adipogenic colon...

Effect of psoralen on bone formation

Journal of Orthopaedic Research — Mon, 01 Mar 2010 00:00:00 +0100

To compare the amount of new bone and bone cells produced by psoralen in collagen matrix to that produced by collagen matrix in vivo. Eighteen bone defects, 5 mm by 10 mm were created in the parietal bone of nine New Zealand White rabbits. Six defects were grafted with psoralen mixed with collagen matrix. Six defects were grafted with collagen matrix alone (negative control - collagen) and six were left empty (negative control - empty). Animals were killed on day 14 and the defects were dissected and prepared for histological assessment. Quantitative analysis of new bone formation and bone cells were made on 100 sections (50 sections for each group) using image analysis. A total of 454% more new bone was present in defects grafted with psoralen in collagen matrix than those grafted with co...

Impact of freezing on immunology and incorporation of bone allograft

Journal of Orthopaedic Research — Mon, 01 Mar 2010 00:00:00 +0100

This study indicates that in the long run there are no significant consequences; either immunological or biomechanical, of the use of deep frozen allogenous bone as compared to fresh autogenous bone grafts in this animal model. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res (Source: Journal of Orthopaedic Research)

Robot-assisted fracture reduction using three-dimensional intraoperative fracture visualization: An experimental study on human cadaver femora

Journal of Orthopaedic Research — Thu, 25 Feb 2010 00:00:00 +0100

Closed fracture reduction can be a challenging task. Robot-assisted reduction of the femur is a newly developed technique that could minimize potential complications and pitfalls associated with fracture reduction and fixation. We conducted an experimental study using 11 human cadaver femora with intact soft tissues. We compared robot-assisted fracture reduction using 3D visualization with manual reduction, using 2D fluoroscopy. The main outcome measure was the accuracy of reduction. The manual reductions were done by an experienced orthopedic trauma surgeon, whereas the robot-assisted reductions were done by surgeons of different experience. The robot-assisted group showed significantly less postreduction malalignment (p < 0.05) for internal/external rotation (2.9° vs. 8.4°) and for var...

Chronic axial compression of the mouse tail segment induces MRI bone marrow edema changes that correlate with increased marrow vasculature and cellularity

Journal of Orthopaedic Research — Thu, 25 Feb 2010 00:00:00 +0100

Magnetic resonance imaging (MRI) of bone marrow edema (BME) has been found to be helpful in the diagnosis of back pain attributed to degenerative disk disease (DDD) and spondyloarthropathy (SA), but its interpretation is limited by a lack of knowledge of its nature and natural history. We assessed effects of compressive forces to mouse tail segments of WT and TNF-Tg mice with SA, via contrast enhanced-MRI and histology. Normalized marrow contrast enhancement (NMCE) of uninstrumented WT vertebrae significantly decrease, threefold (p < 0.01) from 8 to 12 weeks of age, while the NMCE of TNF-Tg vertebrae remained elevated. Compressive loading (6× body weight) increased NMCE twofold (p < 0.02) within 2 weeks in WT tails, which was equal to 6× loaded TNF-Tg tails within 4 weeks. Histology conf...

Injectable gellan gum hydrogels with autologous cells for the treatment of rabbit articular cartilage defects

Journal of Orthopaedic Research — Wed, 24 Feb 2010 00:00:00 +0100

In this work, the ability of gellan gum hydrogels coupled with autologous cells to regenerate rabbit full-thickness articular cartilage defects was tested. Five study groups were defined: (a) gellan gum with encapsulated chondrogenic predifferentiated rabbit adipose stem cells (ASC + GF); (b) gellan gum with encapsulated nonchondrogenic predifferentiated rabbit adipose stem cells (ASC); (c) gellan gum with encapsulated rabbit articular chondrocytes (AC) (standard control); (d) gellan gum alone (control); (e) empty defect (control). Full-thickness articular cartilage defects were created and the gellan gum constructs were injected and left for 8 weeks. The macroscopic aspect of the explants showed a progressive increase of similarity with the lateral native cartilage, stable integration at ...

Anti-biofilm activity of sub-inhibitory povidone-iodine concentrations against Staphylococcus epidermidis and Staphylococcus aureus

Journal of Orthopaedic Research — Wed, 24 Feb 2010 00:00:00 +0100

In this study we report that the antibacterial agent povidone-iodine (PI) also has anti-biofilm activity against Staphylococcus epidermidis and Staphylococcus aureus at sub-inhibitory concentrations (p < 0.001). Inhibition of biofilm by PI correlated with decreased transcription of the icaADBC operon, which in turn correlated with activation of the icaR transcriptional repressor in Staphylococcus epidermidis. These data reveal an additional therapeutic benefit of PI and suggest that studies to evaluate suitability of PI as biomaterial coating agent to reduce device-related infections are merited. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res (Source: Journal of Orthopaedic Research)

Extracellular matrix expression of human tenocytes in three-dimensional air-liquid and PLGA cultures compared with tendon tissue: Implications for tendon tissue engineering

Journal of Orthopaedic Research — Wed, 24 Feb 2010 00:00:00 +0100

Tenocyte transplantation may prove to be an approach to support healing of tendon defects. Cell-cell and cell-matrix contacts within three-dimensional (3D) cultures may prevent tenocyte dedifferentiation observed in monolayer (2D) culture. The present study compares both neotissue formation and tenocyte extracellular matrix (ECM) expression in 2D and 3D cultures directly with that of native tendon, in order to determine optimal conditions for tendon tissue engineering. Primary human tenocytes were embedded in poly[lactic-co-glycolic-acid] (PLGA)-scaffolds and high-density cultures. Neotissue formation was examined by hematoxyline-eosine (H&E) and immunofluorescence staining. Gene expression of ECM proteins and vascular endothelial growth factor (VEGF) was compared at days 0 (2D), 14, and 2...

Distinction between intact and antibiotic-inactivated bacteria by real-time PCR after treatment with propidium monoazide

Journal of Orthopaedic Research — Tue, 23 Feb 2010 00:00:00 +0100

One limitation to the use of the polymerase chain reaction (PCR) to identify orthopedic infections has been apparent false-positive results, possibly due to the detection of dead bacteria. We recently showed that the use of DNA-binding agent propidium monoazide (PMA) could distinguish viable from heat-inactivated bacteria, and, in this study, we investigated whether the same technique can be applied to bacteria killed by two antibiotics with distinctly different mechanisms of action, a test of greater clinical relevance than thermal inactivation. Staphylococcus aureus and S. epidermidis were inactivated by vancomycin and gentamicin and treated with PMA or left untreated before DNA extraction. The threshold cycle difference of antibiotic-treated bacteria with and without PMA pretreatment wa...

Role of myostatin (GDF-8) signaling in the human anterior cruciate ligament

Journal of Orthopaedic Research — Mon, 22 Feb 2010 00:00:00 +0100

Myostatin, also referred to as growth and differentiation factor-8 (GDF-8), is expressed in muscle tissue where it functions to suppress myoblast proliferation and myofiber hypertrophy. Recently, myostatin and its receptor, the type IIB activin receptor (ActRIIB), were detected in the leg tendons of mice, and recombinant myostatin was shown to increase cellular proliferation and the expression of type 1 collagen in primary fibroblasts from mouse tendons. We sought to determine whether myostatin and its receptor were present in human anterior cruciate ligament (ACL) tissue, and if myostatin treatment had any effect on primary ACL fibroblasts. ACL tissue samples were obtained from material discarded during ACL reconstruction surgery. Real-time PCR and immunohistochemistry demonstrate that bo...

Age dependence of expression of growth factor receptors in porcine ACL fibroblasts

Journal of Orthopaedic Research — Mon, 22 Feb 2010 00:00:00 +0100

In this study we hypothesized that these age-related effects are caused by differences in the expression of the receptors for growth factors released from platelet-rich plasma (PRP). Porcine ACL fibroblasts from a predetermined number of animals of different ages were obtained, and mRNA levels of the receptors of platelet-derived growth factor (PDGF), transforming growth factor [beta] (TGF-[beta]), fibroblast growth factor (FGF), and vascular endothelial growth factor (VEGF) were determined. Expression levels were compared across age groups (young and adolescent) and regressed on age in days. While no significant difference was seen across groups, the regression analysis showed decreases in receptor expression with increasing age. These differences were statistically significant for TGF-[b...

Influence of bone density on the cement fixation of femoral hip resurfacing components

Journal of Orthopaedic Research — Wed, 17 Feb 2010 00:00:00 +0100

In clinical outcome studies, small component sizes, female gender, femoral shape, focal bone defects, bad bone quality, and biomechanics have been associated with failures of resurfacing arthroplasties. We used a well-established experimental setup and human bone specimens to analyze the effects of bone density on cement fixation of femoral hip resurfacing components. Thirty-one fresh frozen femora were prepared for resurfacing using the original instruments. ASRTM resurfacing prostheses were implanted after dual-energy X-ray densitometer scans. Real-time measurements of pressure and temperature during implantation, analyses of cement penetration, and measurements of micro motions under torque application were performed. The associations of bone density and measurement data were examined c...

Augmentation of surgical angiogenesis in vascularized bone allotransplants with host-derived a/v bundle implantation, fibroblast growth factor-2, and vascular endothelial growth factor administration

Journal of Orthopaedic Research — Tue, 16 Feb 2010 00:00:00 +0100

In this study, we examine the role of angiogenic cytokine delivery with biodegradable microspheres to enhance this process. Microsurgical femoral allotransplantation was performed from Dark Agouti to Piebald Virol Glaxo rats. Poly(D,L-lactide-co-glycolide) microspheres loaded with buffer, basic fibroblast growth factor (FGF), vascular endothelial growth factor (VEGF), or both, were inserted intramedullarly along with a recipient-derived arteriovenous (a/v) bundle. FK-506 was administered daily for 14 days, then discontinued. At 28 days, bone blood flow was measured using hydrogen washout. Microangiography, histologic, and histomorphometric analyses were performed. Capillary density was greater in the FGF+VEGF group (35.1%) than control (13.9%) (p < 0.05), and a linear trend was found from ...

Matrix metalloproteinase (MMP)-3 gene up-regulation in a rat tail compression loading-induced disc degeneration model

Journal of Orthopaedic Research — Tue, 16 Feb 2010 00:00:00 +0100

The rodent static compression loading-induced disc degeneration model still has important gaps among the radiographic, magnetic resonance imaging (MRI), and histological schemes and the acute and chronic expression of catabolic genes such as matrix metalloproteinase (MMP)-3. Our objectives were to assess the validity of a rat tail two-disc static compression model and to elucidate a representative catabolic marker, MMP-3 gene alterations, throughout the degenerative process. Static compression at 1.3 MPa for up to 56 days produced progressive disc height loss in radiographs, lower nucleus intensity on T2-weighted MRIs, and histomorphological degeneration. Real-time RT-PCR mRNA quantification showed significant MMP-3 up-regulation in nucleus pulposus cells from 7 days and a significantly pr...

Cefazolin embedded biodegradable polypeptide nanofilms promising for infection prevention: A preliminary study on cell responses

Journal of Orthopaedic Research — Tue, 16 Feb 2010 00:00:00 +0100

In this study, we developed cefazolin loaded biodegradable polypeptide multilayer nanofilms on orthopedic implants. We found that the amount of cefazolin released could be tuned. A high local concentration of cefazolin was achieved within the first a few hours and therefore may inhibit bacterial colonization in the critical postimplantation period. The developed cefazolin loaded nanofilms showed their in vitro efficacy against Staphylococcus aureus; the more antibiotics loaded, the longer the nanocoated implant had antibacterial properties. More interestingly, antibiotic-loaded polypeptide multilayer nanofilms also improved osteoblast bioactivity including cell viability and proliferation. These findings suggested that biodegradable polypeptide multilayer nanofilms as antibiotic carriers a...

Wear, delamination, and fatigue resistance of melt-annealed highly crosslinked UHMWPE cruciate-retaining knee inserts under activities of daily living

Journal of Orthopaedic Research — Tue, 16 Feb 2010 00:00:00 +0100

The wear, delamination, and fatigue resistance of artificially aged gamma irradiation-sterilized conventional polyethylene (CPE) and gas-plasma-sterilized melt-annealed highly crosslinked polyethylene tibial inserts (HXPE) were compared. Six CPE and 12 HXPE (six irradiated at 58 kGy and six at 72 kGy) left knee inserts were wear tested for 5.5 million cycles (Mc) under loads and motions that mimic activities of daily living, such as walking, chair rise, stair ascent, and deep squatting. Another six HXPE (72 kGy) and six CPE inserts were also tested under conditions that could produce severe delamination for 8 Mc. Ten other knees (five 72 kGy HXPE and five CPE) were subjected to posterior edge loading fatigue testing for 5 Mc. The HXPE inserts had an average wear rate reduction of about 80%...

Carboxy terminus of secreted phosphoprotein-24 kDa (spp24) is essential for full inhibition of BMP-2 activity

Journal of Orthopaedic Research — Tue, 16 Feb 2010 00:00:00 +0100

Secreted phosphoprotein-24 kDa (spp24) is a bone morphogenetic protein (BMP)-binding protein isolated from bone. It exists in a number of size forms and is hypothesized to function as a BMP latency protein and/or a "slow release" mechanism for BMPs involved in bone turnover and repair. We have examined the hypothesis that proteolytic modification of the C-terminus of spp24 affects its BMP-2-binding properties and bioactivity in the BMP-2-stimulated ectopic bone forming bioassay. Three different size forms of recombinant spp24 that correspond to predicted 18.1 kDa, 16.0 kDa, and 14.5 kDa proteolytic products were compared to full-length (fl) spp24. One of these forms (spp18.1) we hypothesize to be the protein which Urist initially, but apparently inaccurately, called "BMP." Only full-length...

Chondroitin-6-sulfate incorporation and mechanical stimulation increase MSC-collagen sponge construct stiffness

Journal of Orthopaedic Research — Tue, 09 Feb 2010 00:00:00 +0100

In this study, we examined the effect of C6S incorporation and mechanical stimulation cycle number on linear stiffness and mRNA expression (collagen types I and III, decorin and fibronectin) for mesenchymal stem cell (MSC)-collagen sponge TECs. The TECs were fabricated by inoculating MSCs at a density of 0.14 × 106 cells/construct onto pre-cut scaffolds. Primarily type I collagen scaffold materials, with or without C6S, were cultured using mechanical stimulation with three different cycle numbers (0, 100, or 3,000 cycles/day). After 2 weeks in culture, TECs were evaluated for linear stiffness and mRNA expression. C6S incorporation and cycle number each played an important role in gene expression, but only the interaction of C6S incorporation and cycle number produced a benefit for TEC lin...

Failure of xenoimplantation using porcine synovium-derived stem cell-based cartilage tissue constructs for the repair of rabbit osteochondral defects

Journal of Orthopaedic Research — Fri, 05 Feb 2010 00:00:00 +0100

The use of xenogeneic tissues offers many advantages with respect to availability, quality control, and timing of tissue harvest. Our previous study indicated that implantation of premature tissue constructs from allogeneic synovium-derived stem cells (SDSCs) facilitated cartilage tissue regeneration. The present study investigated the feasibility of xenoimplantation of SDSC-based premature tissue constructs for the repair of osteochondral defects. Porcine SDSCs were mixed with fibrin gel, seeded in polyglycolic acid (PGA) scaffolds, and cultured in a rotating bioreactor system supplemented for 1 month with growth factor cocktails. The engineered porcine premature tissues were implanted to repair surgically induced osteochondral defects in the medial femoral condyles of 12 rabbits. Three w...

The effect of high-energy extracorporeal shock waves on hyaline cartilage of adult rats in vivo

Journal of Orthopaedic Research — Fri, 05 Feb 2010 00:00:00 +0100

The aim of this study was to determine if extracorporeal shock wave therapy (ESWT) in vivo affects the structural integrity of articular cartilage. A single bout of ESWT (1500 shock waves of 0.5 mJ/mm2) was applied to femoral heads of 18 adult Sprague-Dawley rats. Two sham-treated animals served as controls. Cartilage of each femoral head was harvested at 1, 4, or 10 weeks after ESWT (n = 6 per treatment group) and scored on safranin-O-stained sections. Expression of tenascin-C and chitinase 3-like protein 1 (Chi3L1) was analyzed by immunohistochemistry. Quantitative real-time polymerase chain reaction (PCR) was used to examine collagen (II)[alpha]1 (COL2A1) expression and chondrocyte morphology was investigated by transmission electron microscopy no changes in Mankin scores were observed ...

In vitro investigation of friction under edge loading conditions for ceramic-on-ceramic total hip prosthesis

Journal of Orthopaedic Research — Thu, 04 Feb 2010 00:00:00 +0100

Edge-loading generates higher wear rates in ceramic-on-ceramic total hip prosthesis (THP). To investigate the friction coefficient (FC) in these conditions, three alumina ceramic (Biolox Forte) 32 mm-diameter components were tested using a hip friction simulator. The cup was positioned with a 75° abduction angle to achieve edge-loading conditions. The motion was first applied along the edge and then across the edge of the cup. First, tests were conducted under lubricated conditions with 25% bovine serum. Next, to simulate an extremely high contact pressure, the tests were run with the addition of a third body alumina ceramic chip inserted between the edge of the cup and the head. Engineering blue was used to analyze the contact area. Reference values were determined using a 0° cup abduct...

Radial shock waves effectively introduced NF-kappa B decoy into rat achilles tendon cells in vitro

Journal of Orthopaedic Research — Thu, 04 Feb 2010 00:00:00 +0100

The purpose of this study was to test if radial shock waves could enhance the introduction of nuclear factor-kappa B (NF-[kappa]B) decoy oligodeoxynucleotides, which is reported to markedly inhibit NF-[kappa]B activation and suppress pro-inflammatory cytokine gene expression, using rat Achilles tendon cells. In the presence of NF-[kappa]B decoy labeled with or without fluorescein isothiocyanate (FITC) in culture media, radial shock waves were applied to the tendon cells in variable conditions and cultivated for 24 h. The transfection rate was assessed by counting FITC-positive cells, and IL-1-induced NF-[kappa]B activation in the cells was assessed. Radial shock waves significantly enhanced introduction of NF-[kappa]B decoy-FITC into the tendon cells. IL-1-induced NF-[kappa]B activation wa...

Transient neutropenia increases macrophage accumulation and cell proliferation but does not improve repair following intratendinous rupture of Achilles tendon

Journal of Orthopaedic Research — Thu, 04 Feb 2010 00:00:00 +0100

Neutrophils are the first leukocytes to invade tendons after an acute injury. They could modulate both the inflammatory response and early repair processes through the release of reactive species, cytokines, growth factors, and proteinases. However, the exact role of these cells in damaged tendons remains unclear. We investigated their role by inducing a transient neutropenia in C57BL/6 male mice using an anti-Ly6C/Ly6G antibody. Placebo mice received only serum. The right Achilles tendon was sectioned and sutured using the 8-strand technique, which allowed immediate weight bearing. A significant increase in macrophage accumulation and cell proliferation was observed in tendons from neutropenic animals compared to the placebo group at days 3 and/or 7 postinjury. However, there was a reduct...

Endothelial progenitor cells promote fracture healing in a segmental bone defect model

Journal of Orthopaedic Research — Thu, 04 Feb 2010 00:00:00 +0100

In conclusion, local EPC therapy significantly enhanced bone regeneration in a segmental defect model in rat femur diaphysis. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res (Source: Journal of Orthopaedic Research)

Immature animals have higher cellular density in the healing anterior cruciate ligament than adolescent or adult animals

Journal of Orthopaedic Research — Wed, 03 Feb 2010 00:00:00 +0100

In this study, we hypothesized that skeletal maturity would significantly affect the cellular and vascular repopulation rate of an ACL wound site. Skeletally Immature (open physes), Adolescent (closing physes), and Adult (closed physes) Yucatan minipigs underwent bilateral ACL transection and suture repair using a collagen-platelet composite. The response to repair was evaluated histologically at 1, 2, and 4 weeks. All three groups of animals had completely populated the ACL wound site with fibroblasts at 1 week. The Immature animals had a higher cellular density in the wound site than the Adult animals at weeks 2 and 4. Cells in the Immature ligament wounds were larger and more ovoid than in the Adult wounds. There were no significant differences in the vascular density in the wound site....

Effect of pro-inflammatory and immunoregulatory cytokines on human tenocytes

Journal of Orthopaedic Research — Tue, 02 Feb 2010 00:00:00 +0100

Tendon injury induces a local inflammatory response, characterized by the induction of pro-inflammatory cytokines. The aim of the present study was to analyze the effects of TNF[alpha], IL-6 and IL-10 on key parameters of tendon homeostasis. Cultured primary human tenocytes were treated with the recombinant cytokines IL-6, IL-10, TNF[alpha], or combinations of TNF[alpha] with IL-6 and IL-10 (10 ng/mL, 6, 24 h). Expression of type I collagen, elastin, MMP-1, TNF[alpha], IL-1[beta], IL-6, IL-10, and suppressors of cytokine signaling (SOCS1, 3) was analyzed with the use of RTD-PCR, immunocytochemistry, and Western blot analysis. In response to TNF[alpha], tenocytes reduced their type I collagen deposition but increased their elastin gene expression and highly upregulated their expression for ...

Differences in the secretome of cartilage explants and cultured chondrocytes unveiled by SILAC technology

Journal of Orthopaedic Research — Thu, 28 Jan 2010 00:00:00 +0100

The main goal of our study was to analyze and compare the profiles of secreted proteins from adult human articular chondrocytes in monolayers, and cartilage explants in culture, using a de novo protein labeling approach. Stable isotope labeling of proteins in culture was used to differentiate between chondrocyte-derived proteins and other preexisting matrix-derived components, or proteins coming from serum or synovial fluids. Proteins in culture supernatants were resolved by one-dimensional SDS-PAGE electrophoresis, and analyzed in tandem with LC/MS-MS (liquid chromatography/double mass spectrometry). Results from stable isotope labeling with amino acids in cell culture (SILAC) were validated by specific immunoblotting of four relevant proteins identified in the secretion media. After 8-10...

Correlating femoral shape with patellar kinematics in patients with patellofemoral pain

Journal of Orthopaedic Research — Wed, 27 Jan 2010 00:00:00 +0100

The etiology of patellofemoral pain is likely related to pathological femoral shape and soft-tissue restraints imbalance. These factors may result in various maltracking patterns in patients with patellofemoral pain. Thus, we hypothesized that femoral shape influences patellofemoral kinematics, but that this influence differs between kinematically unique subgroups of patients with patellofemoral pain. 3D MRIs of 30 knees with patellofemoral pain and maltracking ("maltrackers") and 33 knees of asymptomatic subjects were evaluated, retrospectively. Dynamic MRI was acquired during a flexion-extension task. Maltrackers were divided into two subgroups (nonlateral and lateral maltrackers) based on previously defined kinematic criteria. Nine measures of femoral trochlear shape and two measures of...

Biphasic effects of interleukin-1[beta] on osteoblast differentiation in vitro

Journal of Orthopaedic Research — Wed, 27 Jan 2010 00:00:00 +0100

A rat calvarial cell model of osteoblast differentiation using the formation of bone nodules in vitro as an endpoint was used to assess the effects of IL-1[beta] on osteoblast differentiation. Short-term treatment (2 days) with IL-1[beta] early in culture resulted in increased nodule number and size as well as calcium content in contrast to long-term treatment (6 days) in cultures assessed at 10-12 days. This increase in bone formation was blocked by IL-1 receptor antagonists. Short-term treatment increased COX-2, prostaglandin (PGE2), and iNOS production. Exogenous PGE2 with IL-1[beta] enhanced this effect. COX-2 inhibitors, indomethacin and N-39, blocked 50% of nodule formation. NO donor did not modify effects of IL-1[beta], but iNOS inhibitor (1400W) partially blocked the effects. Howev...

Comparison of differential biomarkers of osteoarthritis with and without posttraumatic injury in the Hartley guinea pig model

Journal of Orthopaedic Research — Wed, 27 Jan 2010 00:00:00 +0100

This study indicates that the biomarkers and progression of OA may differ in the Hartley guinea pig models with and without posttraumatic OA. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res (Source: Journal of Orthopaedic Research)

Rotenone prevents impact-induced chondrocyte death

Journal of Orthopaedic Research — Wed, 27 Jan 2010 00:00:00 +0100

Mechanical insult to articular cartilage kills chondrocytes, an event that may increase the risk of posttraumatic osteoarthritis. Recent reports indicate that antioxidants decrease impact-induced chondrocyte death, but the source(s) of oxidants, the time course of oxidant release, and the identity of the oxidative species generated in response to injury are unknown. A better understanding of these processes could lead to new treatments of acute joint injuries. To that end, we studied the kinetics and distribution of oxidant production in osteochondral explants subjected to a single, blunt-impact injury. We followed superoxide production by measuring the time-dependent accumulation of chondrocyte nuclei stained with the superoxide-sensitive probe dihydroethidium. The percentage of chondrocy...

Intraneural blood flow analysis during an intraoperative Phalen's test in carpal tunnel syndrome

Journal of Orthopaedic Research — Wed, 27 Jan 2010 00:00:00 +0100

This study demonstrated that the blood flow in the median nerve is reduced when Phalen's test is performed in vivo. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res (Source: Journal of Orthopaedic Research)

Gene expression profiling from leukocytes of horses affected by osteochondrosis

Journal of Orthopaedic Research — Wed, 27 Jan 2010 00:00:00 +0100

Osteochondrosis (OC) is a developmental disease that affects growing horses and that severely affects their ability to perform. The genetic basis of its pathogenesis is poorly understood. The aim of the study was to analyze the transcript profile of leukocytes from horses affected with OC. Two transcriptome libraries were constructed from leukocytes of OC-affected and non-OC-affected horses using digital gene expression analysis (DGE) and real-time PCR. Statistical analysis allowed selection of 1,008 tags upregulated in the non-OC-affected group and 1,545 tags upregulated in the OC-affected group. Among these genes, 16 regulated genes and 5 housekeeping genes were selected. Metabolic pathways analysis showed an obvious dysregulation of several signaling pathways related to cartilage format...

Rejuvenation of the inflammatory system stimulates fracture repair in aged mice

Journal of Orthopaedic Research — Wed, 27 Jan 2010 00:00:00 +0100

Age significantly reduces the regenerative capacity of the skeleton, but the underlying causes are unknown. Here, we tested whether the functional status of inflammatory cells contributes to delayed healing in aged animals. We created chimeric mice by bone marrow transplantation after lethal irradiation. In this model, chondrocytes and osteoblasts in the regenerate are derived exclusively from host cells while inflammatory cells are derived from the donor. Using this model, the inflammatory system of middle-aged mice (12 month old) was replaced by transplanted bone marrow from juvenile mice (4 weeks old), or age-matched controls. We found that the middle-aged mice receiving juvenile bone marrow had larger calluses and more bone formation during early stages and faster callus remodeling at ...

Impaired expression of genes regulating cholesterol efflux in human osteoarthritic chondrocytes

Journal of Orthopaedic Research — Wed, 27 Jan 2010 00:00:00 +0100

Altered lipid metabolism has been implicated as a critical player in osteoarthritis (OA). Our study aimed to investigate the expression of genes regulating cholesterol efflux in human chondrocytes and to study the effect of an LXR agonist on cholesterol efflux and lipid accumulation in osteoarthritic chondrocytes. ATP-binding-cassette transporter A1 (ABCA1), apolipoprotein A1 (ApoA1), and liver X receptors (LXR[alpha] and LXR[beta]) mRNA expression levels were evaluated using real-time polymerase chain reaction (PCR) and ApoA1 protein levels by Western blot analysis in normal and osteoarthritic articular cartilage samples. Cholesterol efflux was evaluated in osteoarthritic chondrocytes radiolabeled with [1,2(n)-3H] cholesterol after LXR treatment, while intracellular lipid accumulation was...

Distinct mechanosensitive Ca2+ influx mechanisms in human primary synovial fibroblasts

Journal of Orthopaedic Research — Wed, 27 Jan 2010 00:00:00 +0100

In this study, we investigated the difference between the mechanosensitive channels of human primary synovial fibroblasts (SFBs) and human primary dermal fibroblasts (DFBs) in response to mechanical stretch by uniaxial cyclic stretching and mechanical cell membrane deformation in vitro. Cyclic stretching induced orientation of SFBs and DFBs perpendicularly to the stretching direction. Furthermore, uniaxial stretching increased intracellular Ca2+ levels in both cell types. The perpendicular orientation of DFBs was blocked by gadolinium (III) chloride (Gd3+, a mechanosensitive Ca2+ channel blocker) or ruthenium red (RR, a nonselective Ca2+ channel blocker). However, Gd3+ did not block the stretch-induced perpendicular orientation in SFBs, while RR inhibited this orientation. Similarly, Ca2+ ...

Open blunt crush injury of different severity determines nature and extent of local tissue regeneration and repair

Journal of Orthopaedic Research — Wed, 13 Jan 2010 00:00:00 +0100

Insufficiency of skeletal muscle regeneration is often accompanied with functional deficiencies. The goal of our study was to assess the restoration of peripheral muscle upon injury of different severity. Blunt crush injury of the soleus muscle in rats was induced by a clamp and stepwise amplified in severity by rising the locking level of the clamp, resulting in three different groups (1× lock; 2× lock; 3× lock; n = 30 animals per group). After assessment of the fast twitch and tetanic contraction capacity at days 1, 4, 7, 14, and 42 postinjury sampling of muscle tissue served for analysis of cell proliferation, including satellite cells, apoptosis, and leukocyte infiltration. Contraction force analysis demonstrated significantly higher values of relative muscle strength in the 1× loc...

In vitro inhibition of aggrecanase activity by tetracyclines and proteoglycan loss from osteoarthritic human articular cartilage

Journal of Orthopaedic Research — Tue, 12 Jan 2010 00:00:00 +0100

Tetracyclines were reported to slow down the progression of cartilage damage both in an animal model of osteoarthritis (OA) and in humans. In search for the underlying mechanisms we examined whether tetracyclines possess an inhibitory potential on the activity of aggrecanases and inflammatory mediators and can thus prevent proteoglycan (PG) loss from human articular cartilage. In vitro activity of aggrecanase-1 and -2 was recorded in the presence of 1-100 µM tetracycline, minocycline, or doxycyline. Human knee articular cartilage explants were sorted according to the degree of OA and treated for 10 days with tetracycline derivatives in the presence of interleukin-1 (IL-1[beta]). Synthesis and loss of PGs, nitric oxide (NO), and prostaglandin E2 (PGE2), as well as the viability were determ...

Activation of signal transducer and activator of transcription 3 (Stat3) pathway in osteosarcoma cells and overexpression of phosphorylated-Stat3 correlates with poor prognosis

Journal of Orthopaedic Research — Sat, 09 Jan 2010 00:00:00 +0100

Stat3 expression in cancer may have important prognostic and therapeutic value, but there has been no reports correlating Stat3 expression with prognosis in patients with osteosarcoma. The goal of this study is to correlate patient prognosis with the expression of Stat3 in osteosarcoma tissue and determine the effectiveness of blocking this pathway in osteosarcoma cell lines by Stat3 inhibitor, CDDO-Me. We examine the expression levels of Stat3 and pStat3 in osteosarcoma cell lines and primary tissues by Western blot analysis. We also evaluate the levels of pStat3 expression in osteosarcoma tissue microarray (TMA) by immunohistochemistry. We use clinical data to determine the impact of levels of Stat3 expression on patient prognosis. Finally, we evaluated the effect of CDDO-Me on the inhib...

BMP-7-induced ectopic bone formation and fracture healing is impaired by systemic NSAID application in C57BL/6-mice

Journal of Orthopaedic Research — Fri, 08 Jan 2010 00:00:00 +0100

Nonsteroidal antiinflammatory drugs (NSAIDs) are known to potentially impair the fracture healing process. The aim of the present study was to determine if the impairment of bone healing by systemic NSAID application is, at least in part, due to an interaction of NSAIDs with the bone anabolic BMP-7 pathway. Therefore, we first analyzed fracture healing in control and diclofenac-treated mice, where we not only found a significant impairment of fracture healing due to diclofenac treatment as assessed by biomechanical testing and µCT imaging, but also found high coexpression of bone morphogenetic protein-7 (BMP-7) and cyclooxygenase-2 (COX-2) within the fracture callus of both groups. To experimentally address the possible interaction between BMP-7 and COX-2, we then induced ectopic bone for...

Inhibition of STAT1 accelerates bone fracture healing

Journal of Orthopaedic Research — Fri, 08 Jan 2010 00:00:00 +0100

Skeletal fracture healing involves a variety of cellular and molecular events; however, the mechanisms behind these processes are not fully understood. In the current study, we investigated the potential involvement of the signal transducer and activator of transcription 1 (STAT1), a critical regulator for both osteoclastogenesis and osteoblast differentiation, in skeletal fracture healing. We used a fracture model and a cortical defect model in mice, and found that fracture callus remodeling and membranous ossification are highly accelerated in STAT1-deficient mice. Additionally, we found that STAT1 suppresses Osterix transcript levels and Osterix promoter activity in vitro, indicating the suppression of Osterix transcription as one of the mechanisms behind the inhibitory effect of STAT1 ...

Potential role of tartrate-resistant acid phosphatase 5b (TRACP 5b) as a surrogate marker of late loosening in patients with total hip arthroplasty: A cohort study

Journal of Orthopaedic Research — Fri, 08 Jan 2010 00:00:00 +0100

In a cohort study, the role of the active tartrate-resistant acid phosphatase (TRACP 5b), a marker of bone-resorbing osteoclasts, for the assessment of loosening after total hip arthroplasty (THA), was analyzed, as well as its correlation with osteolysis and multinucleated cell appearance in the retrievals. Eighty THA patients, who went consecutively to the orthopedic department, were asked to participate, and 54 accepted and were enrolled in the study. Finally, 46 subjects were analyzed, clinical-radiographic evaluation was considered the gold standard, serum TRACP 5b was blindly measured, and a cut-off was obtained, by performing a ROC Curve. Based on the gold standard, patients were split by 19 stable and 27 loosened subjects, and results were matched. TRACP 5b was significantly higher ...

Effects of tensile strain and fluid flow on osteoarthritic human chondrocyte metabolism in vitro

Journal of Orthopaedic Research — Fri, 08 Jan 2010 00:00:00 +0100

This study examined the hypothesis that tensile strain and fluid flow differentially influence osteoarthritic human chondrocyte metabolism. Primary high-density monolayer chondrocytes cultures were exposed to varying magnitudes of tensile strain and fluid-flow using a four-point bending system. Metabolic changes were quantified by real-time PCR measurement of aggrecan, IL-6, SOX-9, and type II collagen gene expression, and by determination of nitric oxide levels in the culture medium. A linear regression model was used to investigate the roles of strain, fluid flow, and their interaction on metabolic activity. Aggrecan, type II collagen, and SOX9 mRNA expression were negatively correlated to increases in applied strain and fluid flow. An effect of the strain on the induction of nitric oxid...

Modulation of Wnt signaling influences fracture repair

Journal of Orthopaedic Research — Fri, 08 Jan 2010 00:00:00 +0100

While the importance of Wnt signaling in skeletal development and homeostasis is well documented, little is known regarding its function in fracture repair. We hypothesized that activation and inactivation of Wnt signaling would enhance and impair fracture repair, respectively. Femoral fractures were generated in Lrp5 knockout mice (Lrp5-/-) and wild-type littermates (Lrp5+/+), as well as C57BL/6 mice. Lrp5-/- and Lrp5+/+ mice were untreated, while C57BL/6 mice were treated 2×/week with vehicle or anti-Dkk1 antibodies (Dkk1 Ab) initiated immediately postoperatively (Day 0) or 4 days postoperatively (Day 4). Fractures were radiographed weekly until sacrifice at day 28, followed by DXA, pQCT, and biomechanical analyses. Lrp5-/- mice showed impaired repair compared to Lrp5+/+ mice, as eviden...

Penetration depth method - novel real-time strategy for evaluating femoroacetabular impingement

Journal of Orthopaedic Research — Fri, 08 Jan 2010 00:00:00 +0100

We introduce a new method for computerized real-time evaluation of femoroacetabular impingement (FAI). In contrast to previously presented stress analyses, this method is based on two types of predictions of penetration depths for two rotating bodies: curvilinear and radial penetration depth. This intuitive method allows the analysis of both bony and soft tissue structures (such as cartilage and acetabular labrum) in real time. Characteristic penetration depth patterns were found for different subtypes of FAI, such as cam and pincer pathologies. In addition, correlation between the penetration depths (estimated by applying this method) and the existing contact stresses (estimated by applying the finite element method) of various hip morphologies were found. A strong correlation with predic...

Hyaluronan modulates cell proliferation and mRNA expression of adhesion-related procollagens and cytokines in glenohumeral synovial/capsular fibroblasts in adhesive capsulitis