bluuebunny/crossref_metadata_2025_split huggingface dataset:
Kinematics of the glenohumeral joint: Influences of muscle forces, ligamentous constraints, and articular geometry
Authors: Karduna Andrew R. , Williams Gerald R. , Iannotti Joseph P. , Williams John L. 
Published: February 2005

AbstractDespite recent interest in the study of shoulder kinematics, there is considerable controversy in the literature regarding translations at the glenohumeral joint. The purpose of this study was to investigate the key factors that control shoulder motions, thus leading to a better understanding of joint function. Translation and rotation patterns were studied in fresh‐frozen glenohumeral joints of human cadavers with a six‐degrees‐of‐freedom magnetic tracking device. Shoulders were positioned from maximal internal to external rotation at several arm positions (various elevations and planes of motion). In order to determine the effect of muscle forces, joints were positioned both actively and passively. Additionally, articular surface geometry and ligament origin‐insertion wrap lengths were measured to assess their influences on joint kinematics. When joints were positioned passively, large translations were observed at the extremes of motion. With active positioning, muscle forces tended to limit humeral head translations, principally by restricting rotational ranges of motion. However, when data from the passive model were reanalyzed by considering only the rotational ranges of motion seen actively, no significant differences in translation were found between the two models. Joint conformity was found to have a significant influence on translations during active positioning but not during passive positioning. Glenohumeral ligament wrap lengths, however, correlated with translations when joints were positioned passively but not when positioned actively. Findings from this study emphasize the importance of muscle forces in keeping the humeral head centered in the glenoid. Although large translations are possible, they can be achieved only with increases in rotational ranges of motion associated with the removal of muscle force. Additionally, joint conformity appears to play a role in controlling translations during active motions, whereas capsular constraints become more important during passive motions.
Genetic analysis of structural elastic fiber and collagen genes in familial adolescent idiopathic scoliosis
Authors: Miller N. H. , Sponseller P. , Mims B. , Child A. , Milewicz D. M. , Blanton S. H. 
Published: February 2005

AbstractAdolescent idiopathic scoliosis is a genetic disorder of unknown etiology. Scoliosis is a clinical feature of inherited connective‐tissue disorders including Marfan syndrome. Mutations within the gene of FBN1 (fibrillin 15), a component of the extracellular matrix, are now linked to Marfan syndrome and similar clinical phenotypes. This study investigated the potential association of structural genes encoding for extracellular matrix components of FBN1, elastin, and one of the polypeptides of type‐I collagen (COL1A2) with familial adolescent idiopathic scoliosis. Eleven pedigrees, including 96 individuals, were identified in which adolescent idiopathic scoliosis segregated in an apparent autosomal dominant pattern. Fifty‐two individuals were determined to be affected with scoliosis. Genomic DNA was analyzed by genetic linkage utilizing four intragenic markers for the structural genes FBN1, elastin, and COL1A2. Collectively, our results exclude the structural genes of FBN1. elstin, and COL1A2 as candidate genes within these families. However, when viewed individually, specific markers cannot be excluded within all of the families. This information complements previously reported data that fibrillin production and matrix incorporation from scoliotic fibroblasts in vitro are normal in more than 80% of patients studied.
Braided polypropylene augmentation device in reconstructive surgery of the anterior cruciate ligament: Long‐term clinical performance of 594 patients and short‐term arthroscopic results, failure analysis by scanning electron microscopy, and synovial histomorphology
Authors: Kdolsky R. K. , Gibbons D. F. , Kwasny O. , Schabus R. , Plenk H. 
Published: February 2005

AbstractLong‐term clinical results and short‐term arthroscopic and microscopic findings from two agumented roconstruction procedures for the reptured anterior cruciate ligament are reported. The braided polypropylene ligament augmentation device (Kennedy model) was used with temporary double‐end fixation in 279 patients to augment the attachment of the anterior cruciate ligament after acute proximal rupture and in 315 patients to augment a bone‐tendon‐bone autograft, mainly after chronic instability. Check arthroscopy was performed and the metal fixation hardware was removed after a mean of 11 months. Of the 569 patients evaluated, 101 partial or total breakages of the ligament augmentation device were found. Together with nine breakages detected late in the follow‐up period, 110 (19.3%) failures were found. Most of these failures were accompanied by effusion that was immediately alleviated when the failed device was removed. No generalized synovitis was visible. Scanning electron microscopic analysis of 24 retrieved failed ligament augmentation devices showed fatigue to be the principal failure mode, together with local abrasion at the fracture. synovial biopsies were taken during arthroscopy in 84 patients with and without ligament augmentation device‐failure who had given informed consent, and histological evaluation revealed that in 21 patients, chronic but no acute synovial inflammation was found, and wear particles could be identified in foreign body cells in 17. Statistically, the presence of chronic synovitis was predicted neither by wear particles and foreign body cells nor by abrasion or fatigue failure of the ligament augmentation device. Irrespective of the failures, for which ligament augmentation device removal is recommended, in the final Orthopaedische Arbeitsgemeinschaft Knie evaluation (after a mean of 6.2 year). excellent and good clinical results were found in 83.6% of all 594 patients.
Intrinsic healing capacity and tearing process of torn supraspinatus tendons: In situ hybridization study of α1(I) procollagen mRNA
Authors: Hamada Kazutoshi , Tomonaga Akihito , Gotoh Masafumi , Yamakawa Hideyuki , Fukuda Hiroaki 
Published: February 2005

AbstractTo determine the healing potential and healing process of torn supraspinatus tendons, in situ hybridization was used to localize cells containing α1 type‐I procollagen mRNA. Biopsy specimens of torn supraspinatus tendons from 19 patients with complete‐thickness tears and 13 patients with incomplete‐thickness tears were obtained during surgery. Four macroscopically normal supraspinatus tendons were obtained to serve as normal controls. Specimens were fixed in 10% buffered formalin and embedded in paraffin. A 22‐mer oligonucleotide probe was labeled with digoxigenin and used as an in situ marker. The labeled cells were mainly composed of tenocytes and undifferentiated mesenchymal cells. In complete‐thickness tears, the labeled cells at the proximal tendon stumps in the specimens that were obtained less than 4 months after trauma were significantly more abundant than in the specimens obtained 4 months or more after trauma. However, the number of labeled cells was maintained at the torn portion even in long‐standing incomplete‐thickness tears. The labeled cells at the margins of concomitant intratendinous extensions of the tears were detected even in the long‐standing tears. The intratendinous extensions exhibited more labeled cell than were bursal‐side or joint‐side layers of the tendon substance in the incomplete‐thickness tears (p < 0.05). The torn supraspinatus tendon may possess an intrinsic healing capability in the intermediate and late phases of tendon healing. Incomplete‐thickness tears and concomitant intratendinous extensions can continue to rupture after the initial injury.
Effects of polyethylene on macrophages
Authors: Horowitz Stephen M. , Gonzales Joel B. 
Published: February 2005

AbstractA system was developed to expose macrophages to polyethylene in vitro. Exposure of macrophages to these particles in isolation led to the release of tumor necrosis factor alpha and prostaglandin E2. Exposure of macrophages in co‐culture with osteoblasts to polyethylene particles increased the release of prostaglandin E2 and also led to the release of interleukin‐6. Incubation of radiolabelled calvariae with conditioned medium from macrophages exposed to polyethylene particles alone or to particles in co‐culture with osteoblasts led to bone resorption reflected by release of 45Ca. Incubation with pamidronate was effective in inhibiting resorption stimulated by conditioned medium from macrophages exposed to these particles alone or in co‐culture with osteoblasts. This demonstrates that pamidronate, or other bisphosphonates, may be effective in inhibiting bone resorption at the implant/bone interface in association with the macrophage ressponse to particulate polyethylene. Further investigation into the possible use of pamidronate or other bisphosphonates in the treatment of aseptic loosening is warranted.
Degradation rate of ultra‐high molecular weight polyethylene
Authors: Kurtz S. M. , Rimanc C. M. , Bartel D. L. 
Published: February 2005

AbstractUltra‐high molecular weight polyethylene components for total joint replacement chemically degrade before and after implantation, and the degradation is associated with an increase in density. The goal of this study was to determine the average rate of density change in these components following sterilization by gamma radiation in air as a function of shelf age and implantation time. Using the density gradient column method, density profiles were obtained through the thickness from loaded and unloded regions of 10 retrieved Insall‐Burstein/Posterior‐Stabilized II tibial components and one operating‐room inventory component for which the initial density profile and patient history (if applicable) were known. The average density of the components increased at a constant rate of 0.000186 g/cc/month during the first 50 months after sterilization (r2 = 0.54) but was not significantly affected by loading (p > 0.05). The quantitative degradation rates may be useful to help verify kinetic models to predict bulk degradative changes on the basis of microstructural and chemical processes. This research also suggests the hypothesis that degradation of ultra‐high molecular weight polyethylene can be modeled in terms of changes in bulk or average properties.
Effects of stem length on mechanics of the femoral hip component after cemented revision
Authors: Mann Kenneth A. , Ayers David C. , Damron Timothy A. 
Published: February 2005

AbstractBone loss in the proximal femur at the time of revision hip arthroplasty for a failed primary cemented femoral component can substantially reduce the stability of the revision stem, Use of an extended‐length femoral component has been suggested to aid in achieving long‐term fixation; however, the optimal stem length is unknown, A three‐dimensional finite element model of a charnley‐type revision femoral component in a sclerotic shell of cortical bone devoid of cancellous bone was developed, and five different stem lengths ranting from 140 to 273 mm were used. The interface between the sclerotic bone and cement mantle consisted of fibrous tissue. Distal to the sclerotic bone, bonding was allowed between the cement and bone. Relative motion between the cement and bone was reduced substantially when the stem extended beyond the original defect. Maximum principal stresses in the proximal cement mantle decreased from 7.7 to 5.5 MPa, but cement stresses near the distal tip increased from 7.9 to 10.7 MPa when the stem just bridged the defect. Further increases in stem length reduced the distal cement stresses. Increases beyond two femoral diameters had a minor effect on changes in relative motion, cement mantle stresses, and stresses across the cement‐bone interface. The results suggest that a femoral component that extends beyond the area of cancellous bone defect by two femoral diameters will be most effective in minimizing stresses and motion that could be associated with clinical loosening of the cemented revision. A shorter stem that just bridges the cancellous bone defect left from the primary procedure may not provide adequate distal fixation due to high cement‐bone shear stresses.
Nitric oxide and G proteins mediate the response of bovine articular chondrocytes to fluid‐induced shear
Authors: Das P. , Schurman D. J. , Smith R. Lane 
Published: February 2005

AbstractMechanical loading alters the metabolism of articular cartilage, possibly due to effects of shear stress on chondrocytes. In cultured chondrocytes, glycosaminoglycan synthesis increases in response to fluidinduced shear. This study tested the hypothesis that shear stress increases nitric oxide production in chondrocytes, and nitric oxide then influences glycosaminoglycan metabolism. Inhibitors of nitric oxide synthase, G proteins, phospholipase C, potassium channels, and calcium channels were also analyzed for effects on nitric oxide release and glycosaminoglycan synthesis. Fluid‐induced shear was applied to primary high‐density monolayer cultures of adult bovine articular chondrocytes using a cone viscometer. Nitric oxide release in chondrocytes increased in response to the duration and the magnitude of the fluid‐induced shear. Shearinduced nitric oxide production was reduced in the presence of nitric oxide synthase inhibitors but was unaffected by pertussis toxin, neomycin, tetraethyl ammonium chloride, or verapamil. The increase in glycosaminoglycan synthesis in response to shear stress was blocked by nitric oxide synthase inhibitors, pertussis toxin, and neomycin but not by tetraethyl ammonium chloride or verapamil. The phospholipase C inhibitor, neomycin, also decreased glycosaminoglycan synthesis in the absence of flow‐induced shear. As studied here, shear stress increased nitric oxide production by chondrocytes, and the shear‐induced change in matrix macromolecule metabolism was influenced by nitric oxide synthesis, G protein activation, and phospholipase C activation.
Tissue characterization of symptomatic and asymptomatic disc herniations by quantitative magnetic resonance imaging
Authors: Boos Norbert , Dreier Daniel , Hilfiker Esther , Schade Volker , Kreis Roland , Hora Josef , Aebi Max , Boesch Chris 
Published: February 2005

AbstractThe purpose of this investigation was to determine differences in tissue composition of symptomatic and asymptomatic disc herniations as reflected in T1 and T2 relaxation times (quantitative magnetic resonance investigation of the lumber spine. The longitudinal and transverse magnetic rlaxation times (T1 and T2, respectively) were calculated from a set of 20 images obtained with five single‐slice/multi‐echo sequences at different repetition time values on a commercial whole‐body system (1.5 T). Twenty‐two symptomatic and asymptomatic disc herniations could be matched according to age, gender, disc level, and the extent of herniation (protrusion or extrusion) and were compared with regard to T1 and T2 relaxation times. Symptomatic disc herniations exhibited significantly (pT1 < 0.04 and pT2 < 0.003) shorter T1(ΔT1:–182.1 milliseconds, −15%) and T2(ΔT2: −11.0 milliseconds, −21%) relaxation times than matched asymptomatic herniations. Symptomatic disc herniations also exhibited more advanced disc degeneration as graded by Pearce's criteria (p < 0.01). These results suggest that symptomatic and morphologically matched asymptomatic disc herniations differ with regard to disc matrix composition.
Hydrostatic pressur influences mRNA exprssion of trnsforming growth factor‐β1 and heat shock protein 70 in chondrocyte‐like cell line
Authors: Takahashi Kenji , Kubo Toshikazu , Kobayashi Kappei , Imanishi Jiro , Tkigawa Masaharu , Arai Yuji , Hirasawa Yasusuke 
Published: February 2005

AbstractThe present study investigated the influence of hydrostatic prssure on the exprssion of cytokines and heat shock protein 70 in a chondrocyte‐like cell line. Chondrocyte‐like cells (HCS‐2/8) were exposed to hydrostatic pressur by a special pressure apparatus. Total RNA for cytokines (interleukin‐1β, basic fibroblast growth factor, insulin‐like growth factor‐I, and transforming growth factor‐β1) and for heat shock protein 70 was extracted and was analyzed by a polymerase chain reaction method and Northern blotting. An assay for incorporation of [35S]sulfate was performed to assess proteoglycan synthesis. The expression of transforming growth factor‐β1 mRNA was enhanced after exposure to 5 Mpa of hydrostatic prssure and was reduced after 50 Mpa, whereas the expression of heat shock protein 70 was enhanced following exposure to 50 Mpa of hydrostatic pressure. The incorporation of [35S]sulfate into the cultured cells increased following exposure to 1‐5 Mpa of hydrostatic pressure and decreased following 10‐50 Mpa of pressure. These results suggest that hydrostatic pressure at physiologic levels enhances the expression of transforkming growth factor‐β mRNA in addition to increasing proteoglycan synthesis in chondrocytes and that excessively high hydrostatic pressure reduces the expression of transforming growth factor‐β1 mRNA and increases the expression of heat shock protein 79 mRNA while decreasing proteoglycan synthesis.
Treatment of experimental osteomyelitis by surgical debridement and the implantation of bioerodable, polyanhydride‐gentamicin beads
Authors: Nelson Carl L. , Hickmon Sandra G. , Skinner Robert A. 
Published: February 2005

AbstractOsteomyelitis was induced in the radius in 77 rabbits and confirmed by histological examination and culture. At 4 weeks, the wounds were debrided and the animals were treated with (a) fatty acid dimersebacic acid beads (a bioerodable composite) impregnated with 20% or (b) 10% gentamicin sulfate, (c) placebo beads and intramuscular gentamicin sulfate. (d) placebo beads alone, or (e) debridement only. After 4 weeks, eradication of infection was determined by histological examination and culture. Osteomyelitis was eradicated in 93% of the animals treated with the beads and 20% gentamicin, in 67% of those treated with the beads arid 10% gentamicin, in 25% of those treated with placebo beads and intramuscular gentamicin, in 7% of those treated with placebo beads alone, and in 12.5% of those treated with debridement only (p values from <0.001 to 0.02). Fatty acid dimer‐sehacie acid beads with gentamicin were then implanted in noninfected rabbits, and gentamicin sulfate concentrations in bone, serum, urine, and wound exudate were measured. Gentamicin sulfate was detectable in bone for as long as 8 weeks after implantation. Levels as high as 4,746 g/ml were present in the wound exudate for the first 7 days. Levels in the serum peaked at 1.03 μg/ml. Urine levels peaked at 135 μg/ml.
Evaluation of the effect of joint constraints on the in situ force distribution in the anterior cruciate ligament
Authors: Livesay Glen A. , Rudy Theodore W. , Woo Savio L‐Y. , Runco Thomas J. , Sakane Masataka , Li Guoan , Fu Freddie H. 
Published: February 2005

AbstractThe function of the anterior cruciate ligament was investigated for different conditions of kinematic constraint placed on the intact knee using a six‐degree‐of‐freedom robotic manipulator combined with a universal force‐moment sensor. To do this, the in situ forces and force distribution within the porcine anterior cruciate ligament during anterior tibial loading up to 100 N were compared at 30, 60, and 90° of flexion under: (a) unconstrained, five‐degree‐of‐freedom knee motion, and (b) constrained, one‐degree‐of‐freedom motion (i.e., anterior translations only). The robotic/universal force‐moment sensor testing system was used to both apply the specified external loading to the in tact joint and measure the resulting kinematics. After tests of the intact knee were completed, all soft tissues except the anterior cruciate ligament were removed, and these motions were reproduced such that the in situ force and force distribution could be determined. No significant differences in the magnitude of in situ forces in the anterior cruciate ligament were found between the unconstrained and constrained testing conditions. In contrast, the direction of in situ force changed significantly; the force vector in the unconstrained case was more parallel with the direction of the applied tibial load. In addition, the distribution of in situ force between the anteromedial and posterolateral bundles of the ligament was nearly equal for all flexion angles for the unconstrained case, whereas the anteromedial bundle carried higher forces than the posterolateral bundle at both 60 and 90° of flexion for the constrained case. This demonstrates that the constraint conditions placed on the joint have a significant effect on the apparent role of the anterior cruciate ligament. Specifically, constraining joint motion to one degree of freedom significantly alters both the direction and distribution of the in situ force in the ligament from that observed for unconstrained joint motion (five degrees of freedom). Furthermore, the changes observed in the distribution of force between the anteromedial and posterolateral bundles for different constraint conditions may help elucidate mechanisms of injury by providing new insight into the response of the anterior cruciate ligament to different types of external knee loading.
Effect of freeze‐drying or γ‐irradiation on remodeling of tendon allograft in a rat model
Authors: Toritsuka Yukiyoshi , Shino Konsei , Horibe Shuji , Nakamura Norimasa , Matsumoto Norinao , Ochi Takahiro 
Published: February 2005

AbstractFreezing or freeze‐drying and γ‐irradiation are techniques currently used for processing tendon allografts. However, it is still unknown how these processing methods affect graft remodeling. In this study, we used a rat patellar tendon transplantation model to investigate the effect of various processing methods on remodeling by quantifying loss of collagen labeled with a radioactive isotope. The grafts were divided into the following four groups according to the processing method: fresh‐frozen, freeze‐dried, fresh‐frozen and γ‐irradiated, or freeze‐dried and γ‐irradiated. The percentage of donor collagen, calculated from hydroxyproline content and radioactivity level, was used as an indicator of graft remodeling. At 2 weeks, the level of donor collagen in the fresh‐frozen group was 62%; in the freeze‐dried group, 59%; in the fresh‐frozen and irradiated group, 57%; and in the freeze‐dried and irradiated group, 44%. At 4 weeks, the percentage of donor collagen remaining in grafts decreased to 38% in the fresh‐frozen group, 19% in the freeze‐dried group, 27% in the fresh‐frozen and irradiated group, and 12% in the freeze‐dried and irradiated group. Finally, at 12 weeks, the levels were 19% in the fresh‐frozen group, 20% in the freeze‐dried group, 15% in the fresh‐frozen and irradiated group, and 6% in the freeze‐dried and irradiated group. The percentages of donor collagen in the freeze‐dried and the fresh‐frozen and irradiated groups were significantly lower than that in the fresh‐frozen group at 4 weeks. The values for the freeze‐dried and irradiated group were significantly lower than those for the fresh‐frozen and irradiated group at 4 and 12 weeks. These data suggest that freeze‐drying, freeze‐drying followed by γ‐irradiation, and fresh‐freezing followed by γ‐irradiation temporarily accelerate graft remodeling.