bluuebunny/crossref_metadata_2025_split huggingface dataset:
Healing of the medial collateral ligament following a triad injury: A biomechanical and histological study of the knee in rabbits
Authors: Anderson D. Ron , Weiss Jeffrey A. , Takai Shinro , Ohland Karen J. , Woo Savio L‐Y. 
Published: February 2005

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 such approaches.
Quantitation of in situ contact areas at the glenohumeral joint: A biomechanical study
Authors: Soslowsky L. J. , Flatow E. L. , Bigliani L. U. , Pawluk R. J. , Ateshian G. A. , Mow V. C. 
Published: February 2005

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 cm2 before decreasing with further increased elevation to an average of 2.59 cm2 at 180° of total arm elevation. At 20° internal to the starting rotation, contact areas reached high values 60° earlier (averaged 4.56 cm2 at 60° of total arm elevation) and then remained fairly constant through 120° before decreasing with further increased elevation to 2.51 cm2 at 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 articulating surface.
Metabolic and biochemical status of articular cartilage following cryopreservation and transplantation: A rabbit model
Authors: Schachar N. , McAllister D. , Stevenson M. , Novak K. , McGann L. 
Published: February 2005

AbstractTo determine the fate of transplanted cryopreserved articular cartilage, an animal model employing the proximal humerus in the rabbit has been developed. Previous studies have been hindered by problems of postoperative joint instability, secondary injury due to immobilization, and paucity of cartilage for analysis. This experiment demonstrates the survival and function of transplanted cartilage by quantitative assessment of metabolic and biochemical parameters. Forty‐five New Zealand white rabbits underwent transplantation of the right proximal humerus. In 29 animals, the proximal half of the humerus was resected and replaced by a cryopreserved osteoarticular allograft. Autograft procedures were carried out in the remaining animals. Following sacrifice at 3, 6, 9, and 12 months postoperatively, articular cartilage was analyzed for gross appearance, collagen synthesis, proteoglycan synthesis, and water, hydroxyproline, hexosamine, and hexuronic acid contents. The results indicate that the cryopreserved osteoarticular allografts retained their metabolic and biochemical intergrity and behaved as viable and biologically functional units 1 year postoperatively.
Link protein shows species variation in its susceptibility to proteolysis
Authors: Liu J. , Cassidy J. D. , Allan A. , Neame P. J. , Mort J. S. , Roughley P. J. 
Published: February 2005

AbstractHuman cartilage link protein exists as three native components, while equine, bovine, and porcine cartilage link protein exist as two and Swarm rat chondrosarcoma link protein exists as only one component. These nonhuman link protein components represent intact protein structures, and there is little evidence for proteolytically modified forms in nonhuman tissues. In human cartilage, the proteolytic production of modified link proteins increases with age, whereas high amounts of such products were not seen in the nonhuman tissues. However, the small amounts of link protein fragments that were observed in the nonhuman cartilages were of a similar size to their human counterparts. On digestion of human proteoglycan aggregate with stromelysin, rapid modification of the link protein components occurred, whereas the aggregates from nonhuman cartilages showed incomplete cleavage of their link protein components. The relative resistance of nonhuman link protein to stromelysin may in part be due to a unique amino acid substitution present near the enzymic cleave site.
Initial characterization of the metabolism of intervertebral disc cells encapsulated in microspheres
Authors: Maldonado Brian A. , Oegema Theodore R. 
Published: February 2005

AbstractAdult, canine intervertebral disc cells were isolated with a sequential digestion of pronase and bacterial collagenase. The nonchondrodystrophoid nucleus pulposus exhibits two populations of cells: large notochordal cells and smaller chondrocyte‐like cells. The cells from the transition zone and anulus fibrosus are uniform in size, ranging from 17 to 21 μm. The isolated cells were encapsulated in alginate beads and cultured in Ham's F‐12 medium containing 5% heat‐inactivated fetal bovine serum. Alginate bead formation requires calcium ions and can be reversed with a suitable chelator, thus releasing viable cells. We observed that 58% of the newly synthesized proteoglycans formed large‐molecular‐weight aggregates with hyaluronic acid. The proteoglycans contained low amounts of keratan sulfate (KS) (<5% of the total glycosaminoglycans synthesized). The chondroitin sulfates (CS) consisted of 51–67% as 6‐O‐sulfate and 29–39% as 4‐O‐sulfate, with the remainder (4–10%) present as 4,6‐sulfate for all three zones of the disc. The majority of cells synthesized significant amounts of matrix as evidenced by Alcian Blue staining. By immunohistochemical analysis, the matrix contained chondroitin 6‐sulfate as demonstrated by monoclonal antibodies to the unsaturated disaccharides remaining on the proteoglycan core after chondroitinase ABC digestion. Keratan sulfate was also present in the majority of the matrices around cells. These results emphasize the similarity of the newly synthesized proteoglycans secreted by cells grown in alginate beads to those synthesized by the neonate disc. These experiments also demonstrate the usefulness of this method as a microculture technique for disc cells.
Chondrocytes in agarose culture synthesize a mechanically functional extracellular matrix
Authors: Buschmann Michael D. , Gluzband Yehezkiel A. , Grodzinsky Alan J. , Kimura James H. , Hunziker Ernst B. 
Published: February 2005

AbstractThe ability of chondrocytes from calf articular cartilage to synthesize and assemble a mechanically functional cartilage‐like extracellular matrix was quantified in high cell density (∼ 107 cell/ml) agarose gel culture. The time evolution of chondrocyte proliferation, proteoglycan synthesis and loss to the media, and total deposition of glycosaminoglycan (GAG)‐containing matrix within agarose gels was characterized during 10 weeks in culture. To assess whether the matrix deposited within the agarose gel was mechanically and electromechanically functional, we measured in parallel cultures the time evolution of dynamic mechanical stiffness and oscillatory streaming potential in uniaxial confined compression, and determined the intrinsic equilibrium modulus, hydraulic permeability, and electrokinetic coupling coefficient of the developing cultures. Biosynthetic rates were initially high, but by 1 month had fallen to a level similar to that found in the parent calf articular cartilage from which the cells were extracted. The majority of the newly synthesized proteoglycans remained in the gel. Histological sections showed matrix rich in proteoglycans and collagen fibrils developing around individual cells. The equilibrium modulus, dynamic stiffness, and oscillatory streaming potential rose to many times (>5X) their initial values at the start of the culture; the hydraulic permeability decreased to a fraction (∼1/10) that of the cell‐laden porous agarose at the beginning of the culture. By day 35 of culture, DNA concentration (cell density), GAG concentration, stiffness, and streaming potential were all ∼25% that of calf articular cartilage. The frequency dependence of the dynamic stiffness and potential was similar to that of calf articular cartilage. Together, these results suggested the formation of mechanically functional matrix.
Intraosseous infusion using the osteoport implant in the caprine tibia
Authors: Welch R. D. , Waldron M. J. , Hulse D. A. , Johnston C. E. , Hargis B. M. 
Published: February 2005

AbstractWe evaluated the in vivo animal tolerance to intraosseous infusion via the Osteoport pediatric implant (model 2005PSO, Lifequest Medical, San Antonio, TX, U.S.A.) into the proximal tibia of immature goats and investigated the osseous effects of intermittent and sustained increases in intraosseous pressure (IOP). In group 1 (n = 3) autogenous whole blood was continuously infused (CI) for 5 days at flow rates producing an IOP of 30–45 mm Hg. Group 2 animals (n = 3) underwent a 5‐s high‐pressure infusion (HPI) of lactated Ringer solution (LRS) producing an IOP of 90–125 mm Hg twice daily for 10 days. In group 3, the Osteoports were left in place 5 (n = 2) or 10 days (n = 2) and evaluated for patency at 72‐h intervals. An IOP > 35 mm Hg produced clinical evidence of bone pain. Bone mineral density was significantly increased (p < 0.05) in all implanted tibias (mean 1.04 g/cm2; range 0.87–1.21 g/cm2) compared with controls (mean 0.67 g/cm2; range 0.65–0.71 g/cm2). A nonsignificant increase (+9% to +31%) in periosteal new bone formation occurred in all implanted tibias. In the continuously infused group, there was a significant increase (p < 0.05) in cancellous new bone formation (+ 483%), percentage eroded bone surface (+ 143%), and osteoclast covered bone surface (+ 255%) compared with controls. HPI of LRS did not produce significant bone changes. Seemingly, the Osteoport provided a ready means of intraosseous infusion and may be associated with less complications than current methods of continual vascular access. Bone changes correlated more with the duration than the magnitude of increased intraosseous pressures.
Strains and forces in selected carpal ligaments during in vitro flexion and deviation movements of the hand
Authors: Savelberg H. H. C. M. , Kooloos J. G. M. , Huiskes R. , Kauer J. M. G. 
Published: February 2005

AbstractThe forces induced in tiny wrist joint ligaments must be estimated in order to understand their role in the mechanism of the joint. We estimated forces in a number of selected ligaments in seven human wrist joint specimens, using a noninvasive method. The method is based on the rationale that the force generated in a ligament depends on its change of length with the joint under load. In vitro length changes of the ligaments were determined during flexion and deviation movements of the hand, using a roentgenstereophotogrammetric analysis technique. Subsequently, bone‐ligament‐bone (BLB) preparations were dissected from teh specimens. From these BLB preparations the zero‐force length and the force‐elongation relationship were determined in a material testing machine. The forces generated in the ligaments during flexion and deviation were calculated by combining results on the in vitro ligament length changes, the zero‐force length, and the force‐elongation relationship. Large interspecimen variations of the force patterns were found. Due to this variability, it is not possible to obtain quantitative models for the kinetic behavior of the ligaments. However, qualitative trends could be distilled from the strain and force patterns. It is clear that for most ligaments, the zero‐force lengths were not equal to the lengths they possessed in the neutral position of the hand. Furthermore, it could be shown which motions of the hand would most likely strain a particular ligament. It could be shown that the variations in the force patterns originate mainly from variations in the zero‐force lengths, and from variations in the force‐strain relationship between specimens. These variations might result from real differences between individuals as well as from artifacts introduced by the test method. Uncontrolled effects of frozen storage and unintentional preconditioning might negatively influence the variation. Because these artifacts are present from the initiation of the contribution of ligament forces to the kinematics of the wrist joint, which is very consistent between specimens, is of minor importance.
Forces and moments on the human leg in the frontal plane during static bipedal stance
Authors: Macmahon Edward B. , Carmines David V. 
Published: February 2005

AbstractAn experimental apparatus was assembled that permitted measurement of the vertical and lateral ground reaction forces as the hip is abducted, resulting in foot separations ranging from 0.25 to 71 cm, with the knee in 0° flexion. Twelve healthy volunteers (8 men and 4 women) were tested. The hip joint was located by means of center of rotation measurements on each subject's legs, and the location of the knee joint was determined using anatomical measurements. It was observed that the mediolateral force was nonzero and directed toward the body midline, even when the subject's feet were placed together. With the feet placed at shoulder width, the population mean mediolateral force was 3% of body weight. It was determined that simplifying assumptions based upon either “zero lateral force,” or “zero hip moment,” produced errors, when compared with our measured values, over various ranges of foot separation, with the zero hip moment assumption providing accuracy over a broader range. The inclination of the tibial plateau, with respect to the long axis of the tibia, that would produce minimal mediolateral shear at the knee is presented. Research and clinical applications of our results and techniques are discussed.
Proteoglycans in the compressed region of human tibialis posterior tendon and in ligaments
Authors: Vogel Kathryn G. , Ördög András , Pogány Gábor , Oláh Juliana 
Published: February 2005

AbstractProteoglycan content and tissue morphology were examined in tendons and ligaments from 24 cadavers, ranging in age at the time of death from 1.5 months to 83 years. The region of the human tibialis posterior tendon that passes under the medial malleolus was characterized by cells having a rounded shape, positive staining with alcian blue, and higher glycosaminoglycanuronic acid content than in the more proximal region of the same tendon. Analysis of proteoglycans by sodium dodecyl sulfate/polyacrylamide gel electrophoresis indicated that the predominant small proteoglycan of the proximal/tensional region was decorin, whereas two types of small proteoglycans (decorin and biglycan) and large proteoglycans were present in the region passing under the medial malleolus and presumably subjected to compressive and shear forces in addition to tension. The pattern of proteoglycan accumulation in the compressed region of tendon was basically similar for all individuals and showed no distinctive trends related to age after puberty. In terms of type and amount of proteoglycan, the patellar tendon was like the tensional region of the tibialis posterior. Glycosaminoglycan content in the lateral collateral ligament and anterior cruciate ligament, however, was twofold higher than in the tendons. The ligaments contained large as well as small proteoglycans, just as in the compressed region of tendon.
In vivo effects of naproxen on composition, proteoglycan metabolism, and matrix metalloproteinase activities in canine articular cartilage
Authors: Ratcliffee Anthony , Azzo Walid , Saed‐Nejad Fatemeh , Lane Nancy , Rosenwasser Melvin P. , Mow Van C. 
Published: February 2005

AbstractNaproxen is a nonsteroidal anti‐inflammatory drug commonly used in the clinical treatment of joint disease. In this study, its effect in vivo on the biochemical composition, metabolic activities, and metalloproteinase activities of normal canine articular cartilage was analyzed. The articular cartilage from the knee joints of dogs who had been given naproxen for 4 weeks to maintain a serum level of 40–50 μg/ml was examined. Control animals were given a placebo. Treatment with naproxen was not found to change the composition (water, collagen, and proteoglycan) of the articular cartilage. The culture studies of cartilage explants indicated that proteoglycan synthesis rates were unaffected by the treatment with naproxen but that proteoglycan release from the tissue was suppressed. Analysis of the cartilage for matrix metalloproteinase activities showed reduced activity of neutral matrix metalloproteinase by 80%, of collagenase by 40%, and of gelatinase by 87%, with no change in activity of acid metalloproteinase or of tissue inhibitor for metalloproteinase. These findings indicate that in vivo treatment with naproxen has the capacity to modulate catabolic activities in articular cartilage.
Dynamic elongation behavior in the medical collateral and anterior cruciate ligaments during lateral impact loading
Authors: Yasuda Kazunori , Erickson Ann R. , Beynnon Bruce D. , Johnson Robert J. , Pope Malcolm H. 
Published: February 2005

AbstractThe objectives of this experimental study were to determine (a) how quickly the medial collateral ligament (MCL) and the anterior cruciate ligament (ACL) elongate when a lateral impact force is imparted to the knee and if a person can react rapidly enough to provide protective muscle forces in the case of such an impact. (b) if the MCL and the ACL elongate simultaneously during a lateral impact, and (c) if resection of the ACL affects elongation of the MCL during a lateral impact. Eight whole‐leg cadaver specimens were used. Each leg was mounted vertically in a testing‐frame with the knee in 0 and 30° of flexion. A submaximal impact was delivered from the lateral side by a pendulum instrumented with a force transducer. Elongation of the midsubstance of the MCL and the ACL was measured with Hall‐effect displacement transducers. The ACL was resected and the entire test sequence was repeated. Following a lateral impact, elongation of the MCL and ACL reached peak values by 70 ms. This study indicated that contraction of the leg musculature would not protect the MCL and ACL from injury when a lateral impact load is applied to the knee. The MCL and the ACL never elongated simultaneously during a lateral impact. After lateral impact loading, the time required to reach maximum elongation (peak delay) averaged 52 ms in the anterior MCL fibers and 61 ms in the ACL when the knee was in 0° of flexion. At 30° of flexion, the peak delay averaged 38 ms in the anterior MCL fibers and 22 ms in the ACL. The peak delay of the ACL was significantly greater than that of the MCL at 0° of the flexion (p < 0.05). The opposite was true at 30° of flexion. Resection of the ACL had only minimal effect on the elongation behavior of the MCL.
The maquet procedure: Effect of tibial shingle length on patellofemoral pressures
Authors: Pan H. Q. , Kish V. , Boyd R. D. , Burr D. B. , Radin E. L. 
Published: February 2005

AbstractThe Maquet procedure — elevation of the anterior tibial tubercle — has been recommended for treatment of symptomatic osteoarthrosis of the patellofemoral joint. Although the operation was first described 30 years ago, it remains controversial, both on a clinical and on a biomechanical basis. In addition, deterioration of the long‐term results has been suggested. One of the variables that has been ignored in both clinical and biomechanical studies has been tibial shingle length. In order to judge its effect, we examined contact pressures and areas in 15 cadaver knees with 7 and 20 cm tibial shingle lengths. We found significant patellofemoral pressure diminution only with 2 cm elevations. The short anterior tibial shingle with 2 cm of elevation tipped the patella on its superior pole, with a significant change in angle between the patella and the shingle. We suggest that this creates a potentially less than desirable biomechanical circumstance and believe it may explain the discrepancies among previously published reports.