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At least 199 records · Page 11Linked to original sources
PubMed1989

Knee mechanics after repair of the anterior cruciate ligament. A cadaver study of ligament augmentation.

An experimental knee-testing system was used to investigate the immediate postoperative mechanical state in knees with nonaugmented and augmented repairs of the anterior cruciate ligament. Ligament, repair tissue, and augmentation forces were measured using buckle transducers, and joint motion was measured using an instrumented spatial linkage during the application of 90 N anteriorly-directed tibial loads to seven fresh knee specimens at 0-90 degrees of flexion. Force and motion data were collected from each knee with an intact and excised anterior cruciate ligament, and after performing (1) a nonaugmented repair and an augmented repair using the Ligament Augmentation Device (3M Company) placed either (2) anatomically through the lateral femoral condyle or (3) in the over-the-top position. The forces in the nonaugmented repair and the repair with the augmentation in the two positions were greater than the forces in the intact anterior cruciate ligament with the knee under the same anterior loads; this difference from normal was not significant with the over-the-top augmentation. With the augmentation anatomically placed, the load sharing did not reduce the force in the repair tissue as compared with the nonaugmented case. The over-the-top augmentation, on the other hand, lowered the repair tissue forces at extension while avoiding high repair tissue forces in flexion. The tibia was consistently in an externally rotated configuration compared with normal in both the unloaded and anterior load states with all three repair procedures.

Biomechanical Phenomena↗
PubMed1976

Tension studies of human knee ligaments. Yield point, ultimate failure, and disruption of the cruciate and tibial collateral ligaments.

Ultimate failure strengths of human tibial collateral and anterior and posterior cruciate ligaments were determined at two different loading rates (12.5 and fifty centimeters per minute) using an Instron Tension Analyzer. The posterior cruciate ligament was significantly stronger than the tibial collateral and anterior cruciate ligaments, which were of equal strength. At ultimate failure the ligaments were intact macroscopically but electron microscopy revealed widespread disruption of the collagen fibrils. Only after further application of stress did actual macroscopic disruption occur, suggesting that microscopic failure of the collagen fibrils in grossly intact ligaments may be a significant cause of clinical instability.

Collagen↗
PubMed1989

[Ultrastructural and cytochemical studies of clonal cell lines in fibroblasts derived from human periodontal ligaments--establishment of clonal cell lines in fibroblasts from periodontal ligaments].

It has recently been suggested that fibroblasts in periodontal ligaments have cytochemical characteristics similar to those of osteoblasts and different from those of other connective tissues. The authors isolated clonal cell lines of fibroblast-like cells from human periodontal ligaments in order to clarify their nature. Digestion with collagenase and hyaluronidase was used to isolate the cells from a human periodontal ligament. The cells were then plated in a 96-hole microplate. A single cell in a conditioned medium containing 20%FBS was placed in each hole. From these single cells large colonies ware subcultured. Subculturing was done every 8 days until more than 20 successive generations had been produced. The method developed by Lowry et al. was used to determine the ALPase activity of the cultured cells. From the 768 cells cultured from human periodontal ligament, 7 clonal cell lines were isolated in vitro. Cultures of these clonal cell lines resulted in typical, spindle-shaped, fibroblast-like cells, all of which were homogeneous. Very high ALPase activity was observed in 4 of the 7 cell lines. Enzyme reaction products occurred mainly along cell membranes. These stable clonal cell lines provide suitable systems for in vitro studies related to morphological and functional analysis of fibroblasts in the periodontal ligament.

Alkaline Phosphatase↗
PubMedDate not supplied

New technique for reapproximation of the calcaneofibular ligament after double ligament rupture.

Ankle sprains are often inadequately treated in the emergency room, because of the feeling that, "It is only a sprain." A thorough examination is performed at St. John Hospital Macomb Center to determine the extent of ligamentous damage. If a double ligament rupture presents, and surgical intervention is necessary, a procedure similar to the one described by Bröstrom is performed. The calcaneofibular ligament's frayed ends, as well as its location, make suturing the ligament difficult. Utilizing medium-sized Ligaclips on either side of the rupture provides an excellent scaffold for reapproximation of the calcaneofibular ligament. The Ligaclips could also be used to determine if a re-rupture has occurred.

Adult↗
PubMed1988

[Studies on induction mechanism of ossification of the posterior longitudinal ligament of the spine--especially on the cultured cells from the human spinal ligament].

To determine the mechanism of ossification of the posterior longitudinal ligament (OPLL) of the spine using cultured cells derived from the human spinal ligament, the ossification group and the non-ossification group were compared morphologically and biochemically. The results are as follows: 1) There is a difference in the characteristics of the two groups. The non-ossification group consists chiefly of fibroblast-like cells, while the ossification group consists chiefly of osteogenic un-differentiated mesenchymal cells. 2) In the ossification group, the posterior longitudinal ligament is composed of high osteogenic potential cells, with a resulting general tendency of systemic ossification. This systemic ligamentous ossification factor is a primary cause of OPLL. When localized anatomical stress and/or abnormalities of hormone and bone metabolism stimulate this ligament which is in a high osteogenic activity, this may result in initial ossification which may develop into the pathological OPLL.

Adult↗
PubMedDate not supplied

Ultrasound-guided transection of the accessory ligament of the deep digital flexor muscle (distal check ligament desmotomy) in horses.

Transection of the accessory ligament of the deep digital flexor muscle (distal check ligament desmotomy) was completed in 44 horses using an ultrasound-guided technique. The technique used real-time ultrasound with a 7.5 MHz transducer to observe the dissection and isolation of the check ligament through a 1 to 1.5 cm incision and to check for complete transection of the check ligament. The technique was effective in correcting flexural deformity of the distal interphalangeal joint and the metacarpophalangeal joint in all but three horses. Check ligament desmotomy at a young age (median, 6 months) resulted in more horses with normal foot conformation than when surgery was completed at an older age (median, 12 months). Age at surgery had no effect on subsequent appearance of the surgical site. Based on the authors experience this technique reduced immediate postoperative wound morbidity.

Animals↗
PubMed2000

[The evaluation by CT of bone block position, interference screw placement and replacement of the anterior cruciate ligament after patellar ligament transplantation].

PURPOSE: Evaluation of arthroscopically assisted reconstruction of the anterior cruciate ligament using ligamentum patellae autografts in the bone-tendon-bone technique with special regard to the position of blocks and interference screws. MATERIAL AND METHODS: In a prospective study 28 patients were included after undergoing arthroscopic anterior cruciate ligament replacement surgery. Data thus obtained were correlated with the postoperatively determined functional parameters of the affected joint. RESULTS: Interference screws, bone-blocks and ligamentous transplants could be well imaged using CT. In a comparison of our data with clinical results there was a statistically highly significant correlation between clinical outcome and the position of bone-blocks and interference screws in the tibia. Angles between screw and bone-block exceeding a standard deviation led to significantly worse results, while a divergence in femoral angles did not lead to significantly worse results. CONCLUSION: The postoperative study of anterior cruciate ligament replacement surgery by CT enables the evaluation of the transplant as well as the position of bone-blocks and interference screws.

Adult↗
PubMed1993

Arthroscopically assisted reconstruction of the anterior cruciate ligament with use of autogenous patellar-ligament grafts. Results after twenty-four to forty-two months.

The results of the first sixty-nine consecutive patients who had had seventy arthroscopically assisted reconstructions of the anterior cruciate ligament with use of an autogenous patellar-ligament graft at our institution were reviewed retrospectively. Sixty-seven patients (sixty-eight knees) were available for evaluation after a minimum of two years. All patients had been managed with early, postoperative range-of-motion exercises and a standardized program of physical therapy. At the time of the most recent follow-up evaluation, the median ligament score, according to the rating system of The Hospital for Special Surgery, was 93 of a possible 100 points. Of the sixty-eight knees, forty-four were rated excellent; fifteen, good; six, fair; and three, poor. Eighteen knees had symptoms related to the patellofemoral joint and sixty-three had a full range of motion; two knees had had manipulation for loss of flexion. At the follow-up evaluation, KT-1000 arthrometric measurements were obtained for both knees of fifty-six patients. Eighty-four per cent of the patients had an increase of three millimeters or less in anterior-posterior displacement of the tibia on the reconstructed side compared with the normal side, while 93 per cent had an increase of four millimeters or less. Postoperatively, there was no apparent association between changes in the Insall-Salvati patellar ligament-to-patella ratios and pain in the patellofemoral joint. The results of the arthroscopically assisted reconstructions combined with use of early range-of-motion exercises were comparable with those reported after open reconstruction and immobilization of the limb in a plaster cast. The frequency of pain in the patellofemoral joint and the need for manipulation because of loss of motion were decreased after the arthroscopically assisted procedures.

Adolescent↗
PubMed2003

Valgus medial collateral ligament rupture causes concomitant loading and damage of the anterior cruciate ligament.

This study tested the hypothesis that application of a valgus force necessary to create a complete medial collateral ligament (MCL) injury causes damage to the anterior cruciate ligament (ACL). Twelve cadaveric knees were used to measure concomitant loading and damage to the ACL in valgus knee loading sufficient to cause a grade III MCL injury. Displacement sensors were placed on the anteromedial bundle of the ACL and posterior oblique ligament to monitor tensile strain during creation of the MCL injury. A valgus moment was applied to knees flexed at 30 degrees, displacing the joint into valgus rotation beyond MCL rupture. Following valgus loading and MCL injury, femur-ACL-tibia specimens were tested to failure to compare ACL mechanical integrity to noninjured control specimens. Average ACL strength in MCL ruptured knees (1250 +/- 90 N) was statistically lower (P < or = .05) than that for control knees (2110 +/- 50 N). Strain measurements exhibited concomitant posterior oblique ligament strain during valgus loading, whereas ACL strain increased substantially only after MCL rupture. These data indicate that the ACL can be compromised in isolated grade III MCL injuries.

Anterior Cruciate Ligament↗
PubMed1992

Anterior cruciate ligament allograft transplantation for intraarticular ligamentous reconstruction.

A multiplicity of surgical operations have been developed in an attempt to achieve satisfactory function after anterior cruciate ligament (ACL) repair. None of these procedures have been able to reproduce the fiber organization anatomy of attachment site, vascularity, or function of the ACL. Twenty-nine foxhounds received a deep-frozen bone-ACL-bone allograft and a ligament augmentation device (LAD). Biomechanical, microvascular, and histological changes were evaluated 3, 6, and 12 months following implantation. The maximum loads of the allograft/LADs were 34.3% (387.2 N) after 3 months, 49.3% (556.6 N) after 6 months, and 61.1% (698.8 N) after a year. The maximum load was 69.1% (780 N). In general, after 6 months the allografts showed normal collagen orientation. The allografts demonstrated no evidence of infection or immune reaction. No bone ingrowth into the LAD was observed. Polarized light microscopy and periodic acid-schiff staining showed that the new bone-ligament substance interface had intact fiber orientation at the area of the ligament insertion. Microvascular examination using the Spalteholtz technique revealed revascularization and the importance of an infrapatellar fat pad for the nourishment of ACL allografts.

Angiography↗
PubMed2001

Roles of the anterior cruciate ligament and the medial collateral ligament in preventing valgus instability.

Both the medial collateral ligament (MCL) and the anterior cruciate ligament (ACL) are reported to prevent valgus instability of the knee. In this study, the anatomical mechanisms by which these ligaments prevent valgus instability were experimentally investigated. The valgus rotation angle and the magnitude of the medial joint space opening were measured in six cadaveric knees, using biplanar photography before and after the MCL and/or the ACL were severed. A significant increase in the valgus rotation angle and a large medial joint space opening were observed when the MCL was severed. An increase in the valgus rotation angle was also observed when the ACL was severed, but only a small medial joint space opening was present. The increase in the valgus rotation angle after ACL severance was nearly parallel to the increase in the internal rotation of the tibia. Thus, we concluded that both ligaments function to prevent valgus instability, but that the anatomical reasons for their function are different. The MCL prevents valgus instability by stopping an opening in the medial joint space. The ACL, on the other hand, prevents the internal rotation of the tibia. When the ACL is severed, the internal rotation increases, and causes the valgus rotation angle to also increase, despite the presence of only a small medial joint space opening.

Adult↗
PubMed1994

Comparative investigation on the biomechanical properties of ligament replacement in the sheep knee using six different ligament prostheses.

Six different ligament prostheses were implanted in 40 sheep to replace the anterior cruciate and medial collateral ligament of the right knee. After one year the explanted knee joints were tested for stability by measurement of the anterior drawer. Tensile tests on the ligament replacements were performed to determine the stiffness and rupture force of the replacement. Gross inspection of the knee joint showed abrasion and partial ruptures for all types of prostheses after one year. Depending on the type of prosthesis total rupture rates between 0 and 66% of all implants could be seen. The anterior drawer for the operated knee was 3-4 times higher than for the non-operated contralateral side. Neither the stiffness nor the rupture strength of the replacements reached the biomechanical properties of the normal ligaments.

Animals↗
PubMed2005

Metabolism and composition of the canine anterior cruciate ligament relate to differences in knee joint mechanics and predisposition to ligament rupture.

PURPOSE: The objective of this study was to determine whether differences in the composition and metabolism of the extracellular matrix (ECM) in canine anterior cruciate ligaments (ACLs) might relate to mechanical properties of the canine knee. Variations in ACL biochemistry and knee mechanics could account for divergent predispositions to ligament rupture. METHODS: Eleven knee joints were obtained from both cadaveric Labrador Retrievers (rupture predisposed) and ex-racing Greyhounds (non-rupture predisposed). Anterioposterior laxity and tensile testing determined mechanical properties of the knee joints and ACL samples respectively. The thermal properties of the collagenous matrix were determined by differential scanning calorimetry (DSC) and the biochemical properties by measuring collagen content, collagen cross-links, glycosaminoglycan (GAG) levels, matrix metalloproteinase-2 (MMP-2), tissue inhibitors of metalloproteinase (TIMP). RESULTS: The anterioposterior laxity was significantly greater (p = 0.04) in the Labrador Retriever knee joints, and their ACLs tended to be weaker (p = 0.06). Greater collagen turnover was demonstrated by significantly higher (p = 0.02) concentrations of pro-MMP-2, and lower enthalpy of denaturation (p = 0.05) in Labrador Retriever ACLs. CONCLUSIONS: The different metabolism of the collagenous matrix in the ACLs of dogs predisposed to rupture was related to greater knee joint laxity and lower ligament material properties (ultimate tensile stress). This may be suggestive of a link between ligament rupture and eventual knee osteoarthritis in both dogs and humans.

Animals↗
PubMed1994

Posterior cruciate ligament allograft reconstruction with and without a ligament augmentation device.

Twenty-five patients with posterior cruciate ligament ruptures were treated with either allograft reconstruction alone (10 patients) or with an allograft-ligament augmentation device composite (15 patients). At follow-up (mean 45 months) the results were assessed with the Cincinnati Knee Rating System. There were no significant differences between the two groups for symptoms, functional limitations, sports activity levels, or the overall rating score. The ligament augmentation device provided no benefit. In both groups, the allograft and the allograft composite restored posterior stability at lower functional knee flexion angles, but not uniformly at higher flexion angles (70 degrees). Patients with acute ruptures faired significantly better than did those with chronic ruptures because they had lower anterior-posterior displacements and fewer symptoms and functional limitations. We recommend consideration of early arthroscopic posterior cruciate ligament reconstruction for acute ruptures in active patients. An immediate knee motion program was not deleterious to graft fixation and is recommended.

Acute Disease↗
PubMed2002

Comparison of two methods for reconstruction of the posterior cruciate ligament using a computer based method: quantitative evaluation of laxity, three-dimensional kinematics and ligament deformation measurement in cadaver knees.

The aim of this paper is to present a biomechanical comparison of two different methods for reconstruction of the posterior cruciate ligament in cadaver knees. We used an original computer-based method allowing precise calculation of three-dimensional (3D) knee kinematic parameters as well as the estimation of combined graft deformation (elongation-flexion-torsion). After isolated posterior cruciate ligament (PCL) dissection, double bundle and 'over-the-bottom' methods were performed successively on each knee using synthetic polyester ligaments. The effect of pre-tensioning was tested with the 'over-the-bottom' method. antero-posterior (A-P) and rotational laxity as well as 3D kinematics were recorded and analysed. Our computer based method allowed us to show that both reconstruction methods were equivalent in restoring A-P and rotational laxity as well as kinematic curves. Combined deformation of the prostheses was equivalent for both ligaments.

Aged↗
PubMed1998

Quantitative evaluation of nutritional pathways for the posterior cruciate ligament and the lateral collateral ligament in rabbits.

The cruciate ligament of the knee receives its nutrition from a direct vascular supply and by permeation of nutrients from the synovial fluid. The contributions of these two routes as nutritional pathways are not known in detail. In this study, we injected [3H]methyl glucose as a tracer intravenously or directly into the knee of rabbits. Tracer concentrations in plasma, synovial fluid, the posterior cruciate ligament (PCL), and the lateral collateral ligament (LCL) were analysed by a pharmacokinetic compartment model. The contribution of [3H]methyl glucose permeation from the synovial fluid during steady state was calculated at 44.3% in the PCL and at 39.0% in the LCL. Although these results indicated that more than half the nutrition for both ligaments is provided by its vascular supply, synovial fluid permeation is also an important transport route for small molecules for the PCL and the LCL, which is an extra-articular structure.

Animals↗
PubMedDate not supplied

High tibial osteotomy and ligament reconstruction for varus angulated anterior cruciate ligament-deficient knees.

In a consecutive series, we treated 41 young patients who had anterior cruciate ligament deficiency, lower limb varus angulation, and varying amounts of posterolateral ligament deficiency. Seventy-three percent of the patients (N = 30) had lost the medial meniscus and 63% (N = 26) had marked articular cartilage damage in the medial compartment. All patients were treated with high tibial osteotomy and, in the majority (N = 34), anterior cruciate ligament reconstruction a mean of 8 months later. Posterolateral reconstructions were also required in 18 knees. A 100% follow-up was obtained at a mean of 4.5 years after osteotomy. Gait analysis testing was done in 17 knees before and after osteotomy. At follow-up, a reduction in pain was found in 71% (29 knees); elimination of giving way, in 85% (35 knees); and resumption of light recreational activities without symptoms, in 66% (27 knees). The patient rating of the knee condition was normal or very good in 37% (15 knees) and good in 34% (14 knees). The mean Cincinnati Knee Rating Score significantly improved from 63 to 82 points. The mean adduction moment, 35% higher than controls preoperatively, significantly decreased to below normal values postoperatively. Correction of varus alignment was maintained in 33 knees (80%). We recommend osteotomy in addition to ligament reconstructive procedures in these knees with complex injury patterns.

Adolescent↗
PubMedDate not supplied

Intraarticular injuries associated with anterior cruciate ligament tear: findings at ligament reconstruction in high school and recreational athletes. An analysis of sex-based differences.

BACKGROUND: Despite research on the increased risk of anterior cruciate ligament tears in female athletes, few studies have addressed sex differences in the incidence of associated intraarticular injuries. HYPOTHESIS: When patients are stratified by sport and competition level, no sex differences exist in either the mechanism of injury or pattern of intraarticular injuries observed at anterior cruciate ligament reconstruction. STUDY DESIGN: Prospective cohort study. METHODS: Two hundred twenty-one athletes undergoing anterior cruciate ligament reconstruction met our inclusion criteria of anterior cruciate ligament tear as a singular event without reinjury or history of prior injury or surgery in either knee. Data were collected on competition level (high school, amateur), sport (basketball, soccer, skiing), mechanism of injury, articular cartilage injuries, and meniscal tears. Data were statistically analyzed by sex with the chi-square test and Student's t-test. RESULTS: High school athletes had no significant sex differences in mechanism of injury. Female soccer athletes had fewer medial meniscal tears than did male athletes, and female basketball players had fewer medial femoral condyle injuries. At the amateur level, female basketball players had more contact injuries, an earlier onset of swelling, and fewer lateral meniscal tears than did male players. CONCLUSION: At the high school level, male and female athletes shared a common mechanism of injury, and yet the female athletes had fewer intraarticular injuries in basketball and soccer. If such intraarticular injuries prove to be a significant risk factor for poor long-term outcome, women may enjoy a better prognosis after reconstruction.

Adolescent↗