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At least 991 records · Page 55Linked to original sources
PubMed2005

Application of periodontal ligament cell sheet for periodontal regeneration: a pilot study in beagle dogs.

OBJECTIVE: The ultimate goal of periodontal treatment is to regenerate the damaged periodontal support. Although periodontal ligament (PDL) cells are essential for periodontal regeneration, few studies have reported the transplantation of periodontal ligament cells to periodontal defects. We developed a new method to apply periodontal ligament cells as a sheet to the defect. The aim of this study was to investigate the periodontal healing after application of the periodontal ligament cell sheet in beagle dogs. METHODS: Autologous periodontal ligament cells were obtained from extracted premolars of each beagle dog. Periodontal ligament cell sheets were fabricated using a temperature-responsive cell culture dish. Dehiscence defects were surgically created on the buccal surface of the mesial roots of bilateral mandibular first molars of each dog. In the experimental group (five defects), periodontal ligament cell sheet with reinforced hyaluronic acid carrier was applied to the defect. Only the hyaluronic acid carrier was applied to the contralateral side as a control (five defects). Eight weeks after surgery, the animals were sacrificed and decalcified specimens were prepared. Healing of the periodontal defects was evaluated histologically and histometrically. RESULTS: No clinical signs of inflammation or recession of gingiva were observed in both experimental and control groups. In the experimental group, periodontal tissue healing with bone, periodontal ligament and cementum formation was observed in three out of five defects. In the control group, such periodontal tissue formation was not observed except in one defect. Histometric analysis revealed that the formation of new cementum in the experimental group was significantly higher than that in the control group. CONCLUSION: The periodontal ligament cell sheet has a potential to regenerate periodontal tissue and may become a novel regenerative therapy.

Adjuvants, Immunologic↗
PubMed1989

Evidence for colonization and destruction of hinge ligaments in cultured juvenile Pacific oysters (Crassostrea gigas) by cytophaga-like bacteria.

Several strains of cytophaga-like gliding bacteria (CLB) were isolated as numerically dominant or codominant components of bacterial populations associated with proteinaceous hinge ligaments of cultured juvenile Pacific oysters, Crassostrea gigas. These bacteria were morphologically similar to long, flexible bacilli occurring within degenerative lesions in oyster hinge ligaments. Among bacteria isolated from hinge ligaments, only CLB strains were capable of sustained growth with hinge ligament matrix as the sole source of organic carbon and nitrogen. In vitro incubation of cuboidal portions of ligament resilium with ligament CLB resulted in bacterial proliferation on the surfaces and penetration deep into ligament matrices. Bacterial proliferation was accompanied by loss of resilium structural and mechanical integrity, including complete liquefaction, at incubation temperatures between 10 and 20 degrees C. The morphological, distributional, and degradative characteristics of CLB isolated from oyster hinge ligaments provide compelling, albeit indirect, evidence that CLB are the agents of a degenerative disease affecting juvenile cultured oysters. The motility, metabolic, and hydrolytic characteristics of hinge ligament CLB and the low moles percent G + C values (32.4 to 32.9) determined for three representative strains indicate that they are marine Cytophaga spp.

Animals↗
PubMed2005

Ultrastructural study of the extra-articular Leeds-Keio ligament prosthesis.

BACKGROUND: There have been several histological studies of the Leeds-Keio ligament in anterior cruciate ligament reconstruction, but there have been few of the Leeds-Keio ligament in the extra-articular portion. AIMS/METHODS: To report the histological and ultrastructural findings of two cases of medial patellofemoral ligament reconstruction using the Leeds-Keio ligament, removed 6.1 years and 8.7 years after implantation. RESULTS: In both cases, the tissue over the Leeds-Keio ligament was a ligament-like tissue. Electron microscopy showed that the diameter of the collagen fibrils in the tissue over the Leeds-Keio ligament was unimodal in the case investigated 6.1 years after implantation but bimodal in the case investigated after 8.7 years. CONCLUSIONS: The tissue over the Leeds-Keio ligament may continue to grow with prolonged periods of mechanical stress.

Adolescent↗
PubMed1985

Acute injury of the ligaments of the knee: magnetic resonance evaluation.

Eleven acutely injured knees and 13 normal knees were examined by magnetic resonance imaging (MRI) to assess the value of this modality in detecting acute ligamentous injury of the knee. The presence of torn ligaments in the injured knees was determined by arthroscopy and/or arthrotomy in ten cases and clinical follow-up in one case. The anterior and posterior cruciate ligaments (ACL and PCL) were demonstrated by sagittal spin echo (SE) images through the intercondylar notch (TE = 30 ms; TR = 2,000 ms). The tibial and fibular collateral ligaments (TCL and FCL) were evaluated on coronal SE images (TE = 30 ms, TR = 200 or 530 ms; TE = 120 ms, TR = 2,000 or 2,120 ms). The ACL and PCL were considered torn on MR if they appeared disrupted or were not seen in their normal anatomical positions. The collateral ligaments were considered torn if abnormal high-intensity signal was noted in adjacent soft tissues on TE = 120 ms images or if disruption of a ligament was apparent. Eleven of 15 torn ligaments and 80 of 81 normal ligaments were correctly identified by these criteria. It is concluded that MR imaging may be useful in detecting acute injury of ligaments of the knee.

Acute Disease↗
PubMed1984

Investigation of development, structure and function of the phrenicocolic and duodenal suspensory ligaments.

The development and structure of the duodenal suspensory ligament and the phrenicocolic ligament were studied in the human fetus, newborn and adult. The observations presented show that the superior retention band is transformed into the suspensory ligament of the duodenum. Within this ligament the muscle of Treitz develops. The inferior retention band atrophies. A new ligament, the phrenicocolic ligament, is formed in the fetal period of life. In this ligament, smooth muscle cells develop. The possible functions of the suspensory ligament of the duodenum and the phrenicocolic ligament are discussed.

Adult↗
PubMed1996

Transient introduction of a foreign gene into healing rat patellar ligament.

We investigated the in vivo introduction of a reporter gene into healing rat patellar ligaments using the hemagglutinating virus of Japan (HVJ)-liposome-mediated gene transfer method. The mid-portion of the medial half of the patellar ligament was cut transversely with a scalpel in 14-wk-old male Wistar rats. A HVJ-liposome suspension containing beta-galactosidase (beta-gal) cDNA was injected directly into the injured site and pooled in the fascial pocket covering the injured site 3 d postoperatively. Thereafter, beta-gal-labeled cells were observed in the wound site accounting for 3% of the wound cells on the first day, 2% on the third, 7% on the seventh, 6% on the 14th, 2% on the 28th, and 0.2% on the 56th day after injection. The beta-gal-labeled cells were initially localized in and adjacent to the wound site, but they were observed spreading into the ligament substance away from the wound on the seventh day after injection. On day 28, beta-gal-labeled cells were observed throughout the length of the ligament substance. With double-labeling for marker antigens for monocyte/macrophage (ED-1) and for collagen I aminopropeptide (pN collagen I), it was revealed that fibroblastic (pN collagen I-positive) cells accounted for 63% and monocyte/macrophage lineage cells for 32% of the beta-gal-labeled cells in the day 7 wound. On day 28, they formed 58 and 35% of the beta-gal-labeled cells in the wound, respectively. Thus, we succeeded in introducing the beta-gal gene into healing rat patellar ligament. Moreover, labeling of the transfected cells made it possible to identify a biological event, namely that the cells in and around the wound site infiltrate into the uninjured ligament substance and come to populate the whole length of the ligament substance as repair progresses. These results suggest that ligament healing may involve not only the repair of the wound site itself but also extensive cellular infiltration of ligament substance adjacent to the wound.

Animals↗
PubMed1996

Microvascular luminal volume changes in aged mouse periodontal ligament.

Data for the microvascular bed in the aged periodontal ligament have not been established. This investigation tested the hypothesis that the luminal microvascular volume decreased in the aged ligament. Mice 35 days old and one year old were vascular-perfused and the mandibular first molar periodontal ligament processed for electron microscopy. Tissue quadrats from each circumferential third ligament region were recorded at 150-microns intervals from the alveolar crest to the apex for randomized sampling of blood vessel lumina. The data were analyzed with a generalized linear model at the p < 0.01 level for the interaction of the aging effect with differences across regions. Stereological parameters were established for vessel lumen volume, and for surface and length densities. Mean ligament width decreased from 119.9 +/- 16.94 (micron +/- SE) in young mice to 60.0 +/- 10.58 (micron +/- SE) in aged mice. The luminal volume of 8.63 +/- 1.37 (% +/- SE) in young ligament increased to 9.83 +/- 2.14 (% +/- SE) in aged ligament. Collecting venules and the combined group of arterio-venous anastomoses with terminal arterioles showed a two-fold increase in luminal volume density (p < 0.01). In aged ligament, regional shifts affected the microvascular bed distribution, but these changes were not consistent across regions, or with depth. The average cross-sectional tissue area served per capillary decreased from 2117 microns 2 to 1451 microns 2 for young and old. Average ligament thickness served per capillary dropped from 52.5 microns to 27.5 microns. These reductions in average diffusion distances indicated a change in the quality of the diffusion barrier with age.

Age Factors↗
PubMed2004

In vivo function of the posterior cruciate ligament during weightbearing knee flexion.

BACKGROUND: Current knowledge of posterior cruciate ligament function is mainly based on in vitro cadaveric studies. There are few studies on the in vivo function of the posterior cruciate ligament. The objective of the study was to quantify the multidimensional deformation of the posterior cruciate ligament. HYPOTHESIS: During in vivo weightbearing flexion, the posterior cruciate ligament undergoes complex 3-dimensional deformations, including elongation, twist, and changes in orientation. STUDY DESIGN: In vivo biomechanical study. METHODS: Magnetic resonance images of 5 human knees were used to create 3-dimensional computer models of each subject's knee, including the insertion areas of the posterior cruciate ligament. Orthogonal fluoroscopic images of each subject's knee were acquired as a quasi-static lunge was performed. The images and computer models were used to reproduce the in vivo motion of the knee. The relative motion of the femoral and tibial insertions was described in terms of elongation, twist, elevation (the angle between the tibial plateau and posterior cruciate ligament, measured in the sagittal plane), and deviation (mediolateral orientation, measured in plane of tibial plateau). RESULTS: The length of the posterior cruciate ligament increased significantly with increasing flexion. It twisted almost 80 degrees as the knee flexed from 0 degrees to 90 degrees . The elevation angle remained relatively constant at 50 degrees . The deviation angle was medially oriented by 20 degrees at full extension, then decreased to approximately 10 degrees at 30 degrees through 90 degrees of flexion. CONCLUSION: The posterior cruciate ligament undergoes a complex twisting motion as it elongates with flexion. CLINICAL RELEVANCE: During reconstruction, the tunnels and graft may need to be placed such that the multidimensional deformation of the intact posterior cruciate ligament is reproduced.

Adult↗
PubMed2005

Neuromuscular and biomechanical adaptations of patients with isolated deficiency of the posterior cruciate ligament.

BACKGROUND: Functional adaptations of patients with posterior cruciate ligament deficiency (grade II) are largely unknown despite increased recognition of this injury. HYPOTHESIS: Posterior cruciate ligament-deficient subjects (grade II, 6- to 10-mm bilateral difference in posterior translation) will present with neuromuscular and biomechanical adaptations to overcome significant mechanical instability during gait and drop-landing tasks. STUDY DESIGN: Controlled laboratory study. METHODS: Bilateral comparisons were made among 10 posterior cruciate ligament-deficient subjects using radiographic, instrumented laxity, and range of motion examinations. Biomechanical and neuromuscular characteristics of the involved limb of the posterior cruciate ligament-deficient subjects were compared to their uninvolved limb and to 10 matched control subjects performing gait and drop-landing tasks. RESULTS: Radiographic (15.3 +/- 2.9 to 5.6 +/- 3.7 mm; P = .008) and instrumented laxity (6.3 +/- 2.0 to 1.4 +/- 0.5 mm; P < .001) examinations demonstrated significantly greater posterior displacement of the involved knee within the posterior cruciate ligament-deficient group. The posterior cruciate ligament-deficient group had a significantly decreased maximum knee valgus moment and greater vertical ground reaction force at midstance during gait compared to the control group. During vertical landings, the posterior cruciate ligament-deficient group demonstrated a significantly decreased vertical ground reaction force loading rate. All other analyses reported no significant differences within or between groups. CONCLUSION: Posterior cruciate ligament-deficient subjects demonstrate minimal biomechanical and neuromuscular differences despite significant clinical laxity. CLINICAL RELEVANCE: The findings of this study indicate that individuals with grade II posterior cruciate ligament injuries are able to perform gait and drop-landing activities similar to a control group without surgical intervention.

Adaptation, Physiological↗
PubMed2005

Long-term failure of thermal shrinkage for laxity of the anterior cruciate ligament.

BACKGROUND: Appropriate treatment for anterior cruciate ligament laxity, owing to partial tears of the native ligament or lax reconstruction, is unclear. Studies suggest that a significant percentage of these untreated tears may progress to complete tears or the patient may develop additional injuries to the meniscus or articular cartilage. Shrinkage of the ligament or graft using thermal energy has been proposed as a solution for this problem. PURPOSE: To evaluate the long-term results using thermal energy to shrink laxity of the anterior cruciate ligament. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Nineteen patients with partial tears of the anterior cruciate ligament (n = 14) or stretched anterior cruciate ligament grafts (n = 5) underwent thermal shrinkage treatment. Fourteen were available for follow-up at 1 and 5 years. At 1 year, there were 12 partial tears and 2 grafts available for evaluation. At 5 years, there were 10 partial tears and 4 grafts. Preoperative, postoperative, and intraoperative stability testing was performed using the KT-1000 arthrometer. Clinical results were evaluated using the Cincinnati and Lysholm scoring systems. RESULTS: Intraoperative shrinkage averaged 2.12 mm (17%, P < .0001). At 1 year, 12 of the 14 patients remained stable (86%) with a negative Lachman test result and mean KT-1000 arthrometer maximum side-to-side score of 1.29 mm (P < .001). The 2 failed shrinkages were partial tears of the native anterior cruciate ligament. For these 12 patients, Cincinnati scores improved from 53 to 89 (P < .0001), and Lysholm scores improved from 55 to 89 (P < .0003). At 5-year follow-up, 11 of 13 patients had gone on to complete failure (85%, P < .002; 8/9 partial tears and 3/4 grafts). CONCLUSION: Thermal shrinkage provides short-term benefit in the treatment of anterior cruciate ligament laxity but leads to catastrophic failure in the majority of patients at long-term follow-up. We can no longer recommend this procedure for the treatment of anterior cruciate ligament laxity.

Adult↗
PubMed2005

Anterior cruciate ligament injuries in female athletes: Part 2, a meta-analysis of neuromuscular interventions aimed at injury prevention.

Female athletes have a 4 to 6 times higher incidence of anterior cruciate ligament injury than do male athletes participating in the same landing and pivoting sports. This greater risk of anterior cruciate ligament injury, coupled with a geometric increase in participation (doubling each decade), has led to a significant rise in anterior cruciate ligament injuries in female athletes. The gender gap in anterior cruciate ligament injury, combined with evidence that the underpinnings of this serious health problem are neuromuscular in nature, leads to the development of neuromuscular interventions designed to prevent injury. A systematic review of the published literature yielded 6 published interventions targeted toward anterior cruciate ligament injury prevention in female athletes. Four of 6 significantly reduced knee injury incidence, and 3 of 6 significantly reduced anterior cruciate ligament injury incidence in female athletes. A meta-analysis of these 6 studies demonstrates a significant effect of neuromuscular training programs on anterior cruciate ligament injury incidence in female athletes (test for overall effect, Z = 4.31, P < .0001). Examination of the similarities and differences between the training regimens gives insight into the development of more effective and efficient interventions. The purpose of this "Current Concepts" review is to highlight the relative effectiveness of these interventions in reducing anterior cruciate ligament injury rates and to evaluate the common training components between the training studies. In addition, the level of rigor of these interventions, the costs and the difficulty of implementation, the compliance with these interventions, and the performance benefits are discussed. This review summarizes conclusions based on evidence from the common components of the various interventions to discuss their potential to reduce anterior cruciate ligament injury risk and assess their potential for combined use in more effective and efficient intervention protocols.

Adolescent↗
PubMed2006

Long-term outcome of endoscopic anterior cruciate ligament reconstruction with patellar tendon autograft: minimum 13-year review.

BACKGROUND: Short-term results of anterior cruciate ligament reconstruction are well reported; however, there are no studies evaluating endoscopic reconstruction of the anterior cruciate ligament with a minimum 10-year follow-up. HYPOTHESIS: Anterior cruciate ligament reconstruction with patellar tendon graft affords good subjective results and clinical laxity assessments but may be associated with development of osteoarthritis over the long term. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Endoscopic anterior cruciate ligament reconstruction was performed in 67 consecutive patients without significant articular surface damage. Patients were assessed at 5, 7, and 13 years after surgery with the International Knee Documentation Committee Knee Ligament Evaluation Form, Lysholm knee score, hop tests, kneeling pain, and radiographs. RESULTS: At 13-year review, self-reported assessments remained excellent; 96% of patients reported normal or nearly normal knee function. Grade 0 or 1 results were seen in more than 92% of patients on laxity testing. Patients who had undergone meniscectomy at the time of reconstruction had increased laxity between 7 and 13 years on instrumented testing (P = .03) and 6 times greater odds of anterior cruciate ligament graft rupture than if they had not undergone meniscectomy (95% confidence interval, 1-37). Degenerative changes on radiographs were found in 79% of patients at 13 years and were associated with meniscectomy (P = .006), loss of extension (P = .05), and greater laxity on Lachman test (P = .04). CONCLUSIONS: Endoscopic anterior cruciate ligament reconstruction with patellar tendon autograft affords and maintains good self-reported assessments and clinical ligament evaluation up to 13 years. Radiographic degenerative changes were seen in three quarters of patients. Almost half developed loss of extension, suggesting onset of early osteoarthritis. Patients who had undergone meniscectomy at the time of reconstruction had increased clinical ligament laxity over time and greater odds of graft rupture, possibly reflecting the effect of prolonged increased strain on the graft. Continued follow-up is required to resolve concerns regarding integrity of the patellar tendon graft beyond 13 years, particularly in the absence of meniscal tissue.

Adolescent↗
PubMedDate not supplied

Occult knee ligament injuries associated with femoral shaft fractures.

Recognition of ligamentous injuries of the knee in the acute phase is essential for optimum treatment and prognosis. A multitraumatized patient with a fractured femur and occult knee ligament damage presents a difficult diagnostic challenge. This paper retrospectively reviews 52 patients with 54 midshaft femoral fractures. The high incidence (48%) of ipsilateral knee ligament damage, particularly of a severe nature (30%) evident at followup (mean 24.5 months) is alarming. In the 26 cases of knee ligament damage, the mean time from injury to documentation of instability is 12.8 months. Motor vehicle and athletic injuries and falls account for all of the injuries. The majority are dashboard impacts treated in balanced traction with subsequent case bracing. The anterior cruciate ligament (50%) is most often injured followed by the medial collateral ligament (31%), lateral collateral ligament (13%), and posterior cruciate ligament (6%). A Lachman test, aspiration of the effusions, examinations under anesthesia including stress films, and arthroscopy are recommended as diagnostic procedures. Acute ipsilateral knee instability is a strong relative indication for primary rigid immobilization of the fracture femur to allow early ligamentous repair.

Accidents, Traffic↗
PubMedDate not supplied

A biomechanical study of human lateral ankle ligaments and autogenous reconstructive grafts.

The purpose of this study was to investigate the biomechanical behavior of human anterior talofibular and calcaneofibular ligaments, as well as peroneus brevis, split peroneus brevis, and toe extensor tendon grafts. This article represents the first published data comparing the most frequently injured ankle ligaments to the most commonly used autogenous reconstructive grafts. Twenty fresh human ankles provided the bone-ligament-bone and tendon graft specimens for biomechanical testing on a Minneapolis Testing System. Protocol consisted of cyclic loading at physiologic deflections, followed by several load-deflection tests at varying velocities, followed by a final extremely rapid load to failure test. The load-deflection data for all ligaments and tendons demonstrated nonlinearity and strain rate dependence. The maximum load to failure for the anterior talofibular ligament was the lowest of all specimens tested, while its strain to failure was the highest. The loads to failure of the peroneus brevis and split peroneus tendons were significantly greater than the anterior talofibular ligament and approximately equal to the calcaneofibular ligament. Strains to failure for all tendons were significantly less than ligament strains. The high strain to failure of the anterior talofibular ligament demonstrates its physiologic function of allowing increased ankle plantar flexion-internal rotation, while its low load to failure shows its propensity for injury. The greater strength of the tendon grafts explains the success of most reconstructive procedures in reestablishing stability in chronic ankle sprains; at the same time, the data presented suggest that those surgical procedures sacrificing the entire peroneus brevis tendon are unnecessary.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

A muscle-splitting approach to the ulnar collateral ligament of the elbow. Neuroanatomy and operative technique.

The standard surgical approach for repair or reconstruction of the ulnar collateral ligament of the elbow involves lifting off of the tendon of the common flexor bundle at its origin on the medial epicondyle. However, a more limited muscle-splitting approach may be feasible. A muscle-splitting approach is less traumatic to the flexor-pronator muscle mass, and it could decrease operative time and lessen immediate morbidity after surgery. A proposed muscle-split through the common flexor bundle extends from the medial humeral epicondyle to a point distal to the tubercle of the ulna such that repair or reconstruction can be performed on the ulnar collateral ligament. To examine the feasibility of this approach, we performed a study combining anatomic dissections with clinical observations. We dissected 15 fresh-frozen adult cadaveric elbows to examine the neuroanatomy of the medial side of the elbow. All pertinent nerves were identified and mapped. From these data, we defined a "safe zone" for a muscle-splitting approach to the ulnar collateral ligament that allows adequate room for repair or reconstruction of the ligament without risking denervation of the surrounding musculature. The safe zone extends from the medial humeral epicondyle to approximately 1 cm distal to the insertion of the ulnar collateral ligament on the tubercle of the ulna. Twenty-two patients with ulnar collateral ligament tears underwent either a direct repair or a reconstruction of the ligament using the proposed muscle-splitting approach. With a minimum followup of 1 year, there was no clinical evidence of muscle denervation. From the combined anatomic study and clinical data, we believe that a less traumatic muscle-splitting approach to the ulnar collateral ligament affords a safe and simple surgical approach for repair or reconstruction of the ligament.

Adolescent↗
PubMedDate not supplied

Functional evaluation of the ligaments at the acromioclavicular joint during anteroposterior and superoinferior translation.

We examined the anatomy and measured the in situ force in ligaments at the acromioclavicular joint using a universal force-moment sensor. The in situ force in the coracoacromial, conoid, trapezoid, superior acromioclavicular capsular, and inferior acromioclavicular capsular ligaments of 10 fresh-frozen cadaveric shoulders was determined for a load of 70 N applied to the clavicle in anteroposterior and superoinferior directions. The lengths of the conoid and trapezoid ligaments were found to be 15.1 +/- 4.1 and 11.5 +/- 2.2 mm, respectively; the widths of the conoid and trapezoid ligaments were 10.7 +/- 1.5 and 11.0 +/- 2.8 mm, respectively. The in situ force of the trapezoid (42.9 +/- 15.4 N) was significantly greater than that for the other ligaments during posterior displacement. Otherwise, no statistically significant differences could be found between any of the in situ forces in each ligament during all other motions examined. During anterior displacement, the inferior acromioclavicular capsular ligament appeared to be the major restraint. The trapezoid ligament was the primary restraint during posterior displacement and provided 55.8% +/- 20.0% of the resisting force. Our results suggest that the coracoclavicular and other acromioclavicular joint capsular ligaments should be considered for reconstruction to restore normal joint function, especially in the anterior, posterior, and superior directions.

Acromioclavicular Joint↗
PubMedDate not supplied

Alterations of glycosaminoglycans during patellar tendon autograft healing after posterior cruciate ligament replacement. A biochemical study in a sheep model.

In each of 30 skeletally mature sheep, the posterior cruciate ligament was replaced in one knee by a free patellar tendon autograft using the central third of the ipsilateral patellar tendon. The healing autograft was compared with the contralateral posterior cruciate ligament and the patellar tendons and posterior cruciate ligaments of nonoperated animals. The content of glycosaminoglycans, chondroitin sulfate disaccharides, and dermatan sulfate disaccharides was assessed biochemically at six periods during the 2 years after surgery. The total glycosaminoglycans and chondroitin sulfate disaccharides in the native posterior cruciate ligament was threefold that in the native patellar tendon. In contrast, the amount of dermatan sulfate disaccharides was similar in both the native tendon and native ligament. In the autograft, glycosaminoglycans and chondroitin sulfate disaccharides increased significantly to about 144% and 172%, respectively, of the contralateral posterior cruciate ligament at Week 104. The dermatan sulfate disaccharides in the autograft also showed a significant increase up to Week 26, followed by a remarkable but not significant decrease until the end of the study. In the contralateral posterior cruciate ligament, the dermatan sulfate disaccharides increased significantly between Weeks 52 and 104. Thus, the amount of dermatan sulfate disaccharides was similar in both the autograft and the contralateral posterior cruciate ligament after 2 years. This study suggests that the patellar tendon autograft did not completely assume the biochemical properties of the posterior cruciate ligament.

Animals↗
PubMedDate not supplied

The effects of a popliteus muscle load on in situ forces in the posterior cruciate ligament and on knee kinematics. A human cadaveric study.

To investigate the effect of simulated contraction of the popliteus muscle on the in situ forces in the posterior cruciate ligament and on changes in knee kinematics, we studied 10 human cadaveric knees (donor age, 58 to 89 years) using a robotic manipulator/universal force moment sensor system. Under a 110-N posterior tibial load (simulated posterior drawer test), the kinematics of the intact knee and the in situ forces in the ligament were determined. The test was repeated with the addition of a 44-N load to the popliteus muscle. The posterior cruciate ligament was then sectioned and the knee was subjected to the same tests. The additional popliteus muscle load significantly reduced the in situ forces in the ligament by 9% to 36% at 90 degrees and 30 degrees of flexion, respectively. No significant effects on posterior tibial translation of the intact knee were found. However, in the ligament-deficient knee, posterior tibial translation was reduced by up to 36% of the translation caused by ligament transection. A coupled internal tibial rotation of 2 degrees to 4 degrees at 60 degrees to 90 degrees of knee flexion was observed in both the intact and ligament-deficient knees when the popliteus muscle load was added. Our results indicate that the popliteus muscle shares the function of the posterior cruciate ligament in resisting posterior tibial loads and can contribute to knee stability when the ligament is absent.

Aged↗