摘要:

AbstractThe poor healing abilities of the anterior cruciate ligament (ACL) in contrast to those of the medial collateral ligament (MCL) are well known. Different intrinsic properties of the constituent cells of these ligaments have been proposed to be one of the factors in the differential repair mechanisms. To examine this hypothesis, we have established primary cell lines of ACL and MCL from the tissue explants of approximately similar dimensions and have studied their behavior in vitro. The outgrowth of cells from ACL explants was slower than from MCL explants, as shown by the size of the surrounding clusters of cells. Both ACL and MCL cultures exhibited typical fibroblastic morphology. No significant differences were observed in either attachment or growth of cells from the attached explants derived from various segments of ACL and MCL. Growth curves of ACL and MCL cultures at both passage numbers 2 and 6 showed a slower rate of proliferation of ACL cells than MCL cells (p<0.005). DNA synthesis measured in terms of [3H]thymidine incorporation (CPM/103cells) of both log phase (ACL = 607.5 ± 5.4 vs. MCL = 1356.4 ± 11.3) and confluent (ACL = 83.0 ± 3.6 vs. MCL = 189.8 ± 5.4) cultures, supports the conclusion that differential proliferation rates of these cells exist in culture. FITC‐phalloidin staining (for actin) of later passage cultures (P3‐P5) showed a spread‐out appearance of ACL cells and an elongated appearance of MCL cells. Relatively more stress fibers were seen within ACL cells. SDS‐PAGE and Western blot analysis of cellular proteins revealed higher actin (43 kDa) content in ACL cells than in MCL cells. In vitro wound closure assay was performed by creating a uniform wound of 0.6 mm width in the confluent layer of ACL and MCL cultures. By 48 h postwounding, cell‐free zones created in ACL cultures were occupied partially by single cells in a nonconfluent fashion. In contrast, the wounded zone in the MCL cultures was almost completely covered by the cells. Results presented in this report demonstrate a lower proliferation and migration potential of ACL cells in comparison with MCL cells. These differences in intrinsic properties of ACL and MCL cells that were observed in vitro might contribute to the differential healing potentials of these liga

ISSN:0736-0266    

DOI:10.1002/jor.1100100402

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractQuadrupeds are commonly used as animal models to study healing of anterior cruciate ligament (ACL) reconstructions. While rabbits, dogs, goats, and sheep have been used, goats and sheep are increasingly being employed because of the larger joint size that facilitates surgery, ease of availability, and lower expense to maintain in the farm environment. In spite of this, little is known about the function of the ACL in controlling primary and coupled motions in the quadruped. We report here on the measurements of these motions in goats, with the application of anterior‐posterior forces, varus‐valgus moments, and internal‐external moments in the intact and ACL‐deficient knee. Sectioning the ACL caused significant increases in primary anterior translation, and in varus‐valgus and internal rotations. The increases in anterior translation were similar in amount and dependence on flexion angle to those seen in human knees. The increase in varus averaged 7° and did not depend on flexion angle, whereas the increase in valgus was significant only in the flexed knee. The increases in internal tibial rotation were greatest in extension, whereas the increases in external rotation were small and independent of flexion angle. When the ACL was cut, coupled internal rotation increased with an anterior force as well as a valgus moment. Large increases were seen in coupled anterior translation with the application of varus and valgus moments, whereas smaller increases were seen with internal and external moments. These findings demonstrate that the ACL restrains multiple motions in the goat knee. This study also provides baseline data for future studies of ACL reco

ISSN:0736-0266    

DOI:10.1002/jor.1100100403

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThe effect of a partial medial meniscectomy and anterior cruciate ligament (ACL) transection on medial collateral ligament (MCL) healing was studied in skeletally mature rabbits. Two groups of animals, group I (isolated MCL rupture) and group II (MCL rupture with ACL transection and partial medial meniscectomy), were examined. At 6 and 12 weeks postoperatively, histological examination of the healing MCL and biomechanical evaluation of the varus‐valgus (V–V) knee rotation and tensile properties of the femur‐MCL‐tibia complex (FMTC) were performed. Group II animals experienced substantial joint degeneration by 6 weeks. Progressive osteophyte formation was observed adjacent to the MCL insertions along with proximal migration of the MCL tibial insertion between 6 and 12 weeks. Histologic examination of the healing MCL substance from both groups showed disorganized collagen, inflammation, and fibroblast proliferation that decreased over time. For group II knees, the V–V knee rotation was found to be significantly elevated (4.7 to 5.2 times the contralateral control), and did not decrease with time. In contrast, the V–V knee rotations of the group I specimens were 1.8 times greater than control immediately following injury, and approached control values by 12 weeks. Tensile testing of the FMTCs revealed that the ultimate load increased with time for both groups, but group I had significantly higher values than group II. The linear stiffness in group I was not different than that group II and did not increase with time. For the mechanical (material) properties of the healed MCL substance, the modulus of the healing tissue for group II was only 40% that of group I. The structural properties of the FMTC and the mechanical properties of the MCL substance from both groups at 6 and 12 weeks were significantly different from the contralateral controls. We further demonstrated that immediately after ACL reconstruction, the V–V rotation of group II knees could be restored to group I levels. Recent clinical studies of MCL healing following isolated complete ligament tears have suggested that nonoperative management without immobilization leads to excellent treatment outcome. However, in more severe injuries involving additional tissues, poor quality of the healed ligament tissue and articular degeneration are observed. Our results demonstrate the deleterious effects of an untreated triad injury on the healing of the MCL substance and its insertions. Examination of the MCL substance suggests that a much larger healing mass is formed following a triad injury, which partially compensates for inferior ligament mechanical properties. Therefore, this study indicates that alternative methods may be necessary to optimize MCL healing following a triad injury. Future studies will determine the consequences of su

ISSN:0736-0266    

DOI:10.1002/jor.1100100404

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractAlthough numerous studies have addressed the presence of cartilage canals within developing epiphyses, the chronology of their appearance and their vascular contribution to the developing chondroepiphysis remain to be studied. We have selected a model, similar to the developing human skeletal system, in which extensive cartilage canal development precedes the subsequent secondary ossification process. In the rabbit proximal tibia, both chondroepiphyseal and vascular (cartilage canals) development were quantified from the first evidence of vessels until the formation of the secondary center of ossification. The volume of hyaline cartilage increased 25 times after intraepiphyseal vessels were initially observed. The blood supply, measured in cartilage canal volume, increased 400‐fold over the same period. Three distinct cartilage canal morphologies were identifiable before the formation of the secondary center of ossification: (a) an early phase, in which the canals appeared as infoldings derived from the perichondrium; (b) a reactive phase, occurring simultaneously with chondrocyte hypertrophy and characterized by a very large increase in mesenchymal cells within the cartilage canal; and (c) a vascular phase, coincident with mineralization of the matrix, in which the familiar, unitary canal morphology was replaced by that of a vascular plexus. While matrix mineralization and the formation of bone seem dependent on critical cellular events, notably chondrocyte hypertrophy, the role that the vascular supply plays in developing sufficient biological inertia for the ossifying transition must not be underestimate

ISSN:0736-0266    

DOI:10.1002/jor.1100100405

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractSpecific modifications of the proteoglycan (PG) structure of osteoarthritic (OA) dog cartilage in relation to endogenous metalloprotease activity were examined using murine anti‐proteoglycan monoclonal antibodies (MoAbs). OA lesions were induced over a period of 8 weeks in crossbred dogs (Pond‐Nuki model). The articular cartilage was removed and homogenized in a Tris buffer, pH 7.5, and then divided into four groups: direct PG extraction, no addition, presence of 1 mM p‐aminophenyl mercuric acetate (APMA), and presence of 1 mMAPMA and 10 mM o‐phenanthroline, incubated for 42 h at 37°C followed by PG extraction. MoAbs reactive with PG protein and carbohydrate epitopes included 1C6, 3B3, 5D4, D1B2, and m4D6. The results showed marked alterations induced by APMA activation of the endogenous metalloproteases. PG changes were apparent at at least three sites: one was either in the hyaluronic acid‐binding region or between the hyaluronic‐binding region and the G2 globular domain, another was between the keratan‐sulfate‐rich domain and the chondroitin sulfate‐attachment domain, and a third was in the chondroitin sulfate‐attachment domain. Constitutive metalloprotease activity resulted in less marked PG alterations with preservation of functional PG aggre

ISSN:0736-0266    

DOI:10.1002/jor.1100100406

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractGlenohumeral arthritis may result from abnormal articular mechanics, and shoulder reconstructive procedures often rely implicitly on the belief that the restoration of normal articular mechanics is required to obtain satisfactory clinical results. Despite this, limited knowledge of normal or pathologic glenohumeral joint articular mechanics and contact is available. This study uses a stereophotogrammetry technique to determine contact areas in normal cadaver glenohumeral joints with intact ligaments and capsule through a large range of motion using simulated forces of the four rotator cuff muscles and three deltoid heads. All shoulders were first elevated to their maximum elevation in the scapular plane at an external rotation (starting rotation = 40 ± 8°), which allowed each shoulder to attain its maximal elevation in the scapular plane, and then repeated at 20° internal to this rotation. Contact areas consistently increased with increasing elevation until 120° to an average of 5.07 cm2before decreasing with further increased elevation to an average of 2.59 cm2at 180° of total arm elevation. At 20° internal to the starting rotation, contact areas reached high values 60° earlier (averaged 4.56 cm2at 60° of total arm elevation) and then remained fairly constant through 120° before decreasing with further increased elevation to 2.51 cm2at 180° total arm elevation. With increasing elevation in the external starting rotation, humeral head contact dramatically migrates from an inferior region to a superocentral‐posterior region while glenoid contact shifts posteriorly. When the humeral shaft is positioned 20° internal to the starting rotation, humeral head contact shifts from inferocentral‐anterior to superocentral‐posterior regions. Simultaneously, a similar posterior shift in glenoid contact is observed. Furthermore, whereas only a small portion of the humeral head surface area is in contact in any given position, contact on the glenoid surface is much more uniformly distributed over its entire arti

ISSN:0736-0266    

DOI:10.1002/jor.1100100407

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThe pressure distribution properties of the normal talocalcaneal joint were studied in 13 fresh cadaver specimens using pressure‐sensitive film. The film was inserted into the joint through a posterior approach for the posterior facet and an anteromedial approach for the anterior/middle facet. Specimens, comprising the distal half of the tibia and fibula and the intact ankle and foot, were positioned in neutral in the sagittal plane. In the coronal plane, specimens were positioned in neutral, inversion, or eversion, and the contact characteristics were determined in varying positions, with and without loading the fibula, under axial loads of 350 N, 700 N, 1,050 N, and 1,400 N. The transducers were video imaged for quantitative analysis of area and pressure. The contact/joint area ratio increased significantly with applied load in the posterior facet [e.g., in eversion from 0.336 (SD = 0.195) at 350 N to 0.631 (SD = 0.225) at 700 N], as did the proportion of the contact area>6 MPa, indicating an increase in contact pressure. The contact/joint area ratio was significantly lower in inversion than in any other position of the foot; however, high‐pressure zones were similar, indicating that higher pressures occur in inversion. In the anterior/middle facets both contact/joint area ratio and high pressure/contact area ratios increased significantly to 700 N, but not with further load increase. At 350 N the anterior/middle facet contact area was 31% that of the posterior facet, yet it carried 63.3% of the load of the posterior facet, so its mean contact pressure was 1.44 MPa compared with 0.93 MPa for the posterior facet. Increasing the percentage of the total load carried by the fibula from 0 to 10% increased the posterior facet contact/joint area ratio from 0.595 (SD = 0.152) to 0.774 (SD = 0.1

ISSN:0736-0266    

DOI:10.1002/jor.1100100408

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractIn this study we determined the effects of misalignment of the talar neck on the contact characteristics of the subtalar joint. Each of seven fresh cadaver lower extremities was mounted in a loading jig and a vertical load was applied, 90% of which was directed through the tibia and 10% through the fibula. The foot was allowed to displace freely in the horizontal plane so that relative rotations, known to occur in the subtalar joint, would not be prevented. Pressure‐sensitive film, inserted into the posterior and anterior/middle articulations, was used to quantify changes in contact characteristics. After testing in the normal condition, the talar neck was osteotomized and stabilized with internal and external skeletal fixation. Contact characteristics were then determined in each of the following stages: anatomic realignment, or with 2‐mm displacement of the talar neck either dorsally, medially, laterally, or complex (dorsal and varus) with respect to the body of the talus. Measurements showed no significant changes in overall contact area or high pressure area in the posterior facet, although four of the seven specimens demonstrated increased localization of the contact area into two discrete regions. The combined anterior/middle facet, on the other hand, was significantly unloaded by all but medial displacement of the talar neck. An extraarticular load path and/or increased loading directly on the talonavicular joint was presumed to account for the loss of load transfer in the talocalcaneal jo

ISSN:0736-0266    

DOI:10.1002/jor.1100100409

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractMagnetic resonance imaging was used to determine theT2relaxation times of prepared proteoglycan solutions and of normal human intervertebral disc tissue from the annulus fibrosus (AF) and nucleus pulposus (NP). The collagen, proteoglycan, and water contents of the disc tissue samples were determined by biochemical assays after they were scanned. Correlations among 1/T2, collagen, proteoglycan, and water contents of the tissue samples and among 1/T2, water, and proteoglycan contents of the proteoglycan solutions were calculated. A moderate negative correlation between 1/T2and water content was noted for the tissue samples, and a very high negative correlation was found between 1/T2and water content for the proteoglycan solutions. The very high positive correlation between 1/T2and proteoglycan content of the proteoglycan solutions is probably due to this negative correlation between 1/T2and water content. There was no significant correlation between 1/T2and proteoglycan content of the tissues. The moderate positive correlation between 1/T2and collagen content is probably due to the high negative correlation between collagen content and water content. No significant correlation was found between the collagen and proteoglycan contents of the tissues. Thus it appears that the data confirm previous reports in the literature that the collagen of the disc tissue functions to control its water content.

ISSN:0736-0266    

DOI:10.1002/jor.1100100410

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThe osteoconductive capacity of fibrillar collagen‐biphasic calcium phosphate composition was compared to autogenous bone in a canine spinal fusion model. All animals underwent a standard intervertebral body fusion (L2–L4) with rigid internal fixation and received either autogenous bone alone or a mixture of the ceramic and autogenous bone (3:1) as the graft material. Animals were followed for 12 months and the quality of fusion in each animal assessed by biomechanical testing and histological analysis. The fused L2–L4 segment of each dog was embedded in bone cement and mounted in a specially designed mechanical tester for testing in flexion, extension, and side bending. Overall, the mean rigidity of the fusion mass was not significantly different between the two groups [10.5 ± 4.1 (SD) for autogenous bone vs. 11.3 ± 1.7 for the ceramic plus autogenous bone, p>0.05]. Similar findings were obtained for mean bending moment, compressive load, angular deformation, and energy absorbed for the two groups. Histological analysis was performed on transverse nondecalcified specimens. Quantitation of bone ingrowth using back‐scattered electron imaging disclosed no significant differences in the amount of new bone formed at the graft site between autogenous bone and the ceramic plus autogenous bone recipients (23.4 ± 10% vs. 25.8 ± 8.8%) when correction for the autogenous bone volumes was performed. Light microscopic analysis of toluidine blue‐stained transverse sections demonstrated new bone growth around and through the ceramic bone graft material. These results suggest that use of a collagen‐biphasic calcium phosphate ceramic and autogenous bone mixture (3:1) provides a suitable osteoconductive alternative to the use of autogenous bone and results in the formation of a mechanically competent fusion mass not significantly different from that obtained with autoge

ISSN:0736-0266    

DOI:10.1002/jor.1100100411

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY