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At least 163 records · Page 9Linked to original sources
PubMed1988

[Injuries of the medial collateral ligament and anterior cruciate ligament of the knee joint and its surgical-functional treatment using the Lemaire technic].

The operative-functional treatment of ligamentous tears of the knee joint avoids additional damage due to immobilisation and shortens the rehabilitation period. The basic idea and details of the Lemaire operations are explained. With an average follow up time of 3.5 years, 113 ligamentous plasties mainly for recent tears of the medial collateral and anterior cruciate ligament have been clinically and radiologically assessed by an independent surgeon. Excellent and good results were obtained in 80 to 90% of the patients. The lateral plasty for torn anterior cruciate ligaments prevents successfully antero-lateral subluxation and thus protects the menisci from tear and the cartilage from degenerative alteration. No obvious increase of torn menisci and degenerative signs could be detected in our series of evaluated knees. The Lemaire procedure for old and recent tears of the medial collateral and the anterior cruciate ligament carries little operative risk and inconvenience for the patient and is indicated in any age group, for the young patient as well as for the older but still active person. We recommend the Lemaire operation as an alternative method in treating ligamentous injuries of the knee joint.

Follow-Up Studies↗
PubMed1982

[Morphology and function of the interspinal ligaments and the supraspinal ligament of the lumbar portion of the spine].

The collagenous bundles of fibres in the lumbar interspinous spaces belong to different anatomical structures: the true interspinous ligaments, connecting two neighboured spinous processes in a postero-cranial direction, and fibres, lying in the dorso-caudal part, belonging to the thoracolumbar fascia (aponeurosis of the sacrospinal muscle). In the lumbo-sacral segment there are additional fibres arising from the dorsal part of the 5th lumbar spinous process and descending in a postero-caudal direction, interlacing with the thoracolumbar fascia. Superficial to the thoracolumbar fascia the fibres of the supraspinous ligament pass several spinous processes and form a longitudinal cord. Caudally the supraspinous ligament ends normally at the 4th lumbar spinous process. Below the caudal end of the supraspinous ligament the fibres of the thoracolumbar fascia cross to the opposite side and form a scissor-latticed structure. The interspinous ligaments limit the ventral-flexion of the lumbar spine; they can be extended in extreme retro-flexion, too. Downwards of L4 the fibre-texture of the thoracolumbar fascia permits a greater extent of ventral-flexion. In these segments the erector spinae muscle has to ensure the stability of the spine motion segments instead of a longitudinal ligamentous connection.

Fascia↗
PubMed2005

Histological evaluation of medial patellofemoral ligament reconstructed using the Leeds-Keio ligament prosthesis.

In a total of 15 knees from 15 patients undergoing medial patellofemoral ligament reconstruction using an artificial substitute and a medial retinaculum slip coverage for recurrent patellar dislocation, the reconstructed ligaments were histologically evaluated using hematoxilin-eosin and elastic van Gieson stains. The artificial substitute was a mesh-type Leeds-Keio ligament. The mean age of the patients at the time of surgery was 20 years (range; 13-38 years). The mean interval from initial reconstruction to gathering was 53 months (range; 11-109 months). In the tissue over the artificial ligament, longitudinally aligned collagen fiber bundles with spindle-shaped nuclei were formed in all specimens except one specimen of 11 months postsurgery, but it seemed to be mature ligament only in specimens more than 60 months postsurgery. The tissue inside the artificial ligament was immature as a whole in all specimens, although 13 out of the 15 specimens had regularly aligned collagen fiber bundles slightly or in some portions.

Adolescent↗
PubMed1999

Electron microscopic evaluation of the effects of stress-shielding on maturation of the mid-substance and ligament-bone junction of the reconstructed anterior cruciate ligament in rabbits.

To analyze the effects of stress-shielding on graft maturation after the anterior cruciate ligament (ACL) reconstruction, autogenous ACL reconstruction using Achilles tendon was performed in rabbits. Two-end fixation with a ligament augmentation device (LAD), as a stress-shielding model (SS group), and pull-out fixation with Leeds-Keio artificial ligaments (L-K ligament), as a non-stress-shielding model (non-SS group), were investigated. Intact ACL was used as the control. Specimens were harvested 6 mon postoperatively, and the analysis was focused on collagen fibril maturation in the mid-substance and bone-anchoring pattern in the bone tunnel, under light and transmission electron microscopy. The density of collagen fibrils in the control was lower than that in both experimental groups (p<0.01). The per cent collagen area in the control was higher than that in the SS (p<0.01) and the non-SS group (p< 0.05). The per cent collagen area in the non-SS group was higher than that in the SS group (p<0.05). At the ligament-bone interface, intracellular calcification of the degenerated chondrocytes occurred in the non-SS group, while in the SS group hydroxyapatite deposits were observed only in the extracellular matrix. These results show unfavorable influence of stress-shielding on graft maturation not only in the mid-substance but also at the ligament-bone junction.

Journal Article↗
PubMed1992

[Synthetic replacement of the anterior cruciate ligament--effects on the remaining ligament structures].

In a three-dimensional anatomical knee joint model all major ligaments were replaced by six nylon fibers and length-pattern changes registered and computed during motion between 0-140 degree. Then anteromedial, posteromedial and intermedial fibers were replaced by an artificial ligament made from Aramid (one to three bundle prothesis) and length changes of the remaining ligaments investigated. The result revealed a dynamic feed-back with characteristic changes in the posterior and collateral ligaments in comparison to the reference. A synthetic replacement using a one bundle prothesis in the isometic tracking led to disapointing results. Best correlations were achieved mimicking the anatomic situation by use of a three bundle prothesis with nearly no changes in the length pattern of the remaining ligaments.

Anterior Cruciate Ligament↗
PubMed1994

Interface and biocompatibility of polyethylene terephthalate knee ligament prostheses. A histological and ultrastructural device retrieval analysis in failed synthetic implants used for surgical repair of anterior cruciate ligaments.

In a prospective clinical study of 54 patients with acute anterior cruciate ligament instability, 56 artificial ligaments made of polyethylene terephthalate (Trevira hochfest) were implanted to restore knee stability. The average follow-up of these artificial knee ligaments was 40.2 (12-79) months; five implants (10%) had to be explanted due to failure after an average of 17.8 (6-50) months. All explants were examined by histological and ultrastructural methods in a device retrieval analysis. With regard to short- and medium-term artificial ligament failure in the human knee joint, a non-isometric surgical implantation technique, inappropriate strain during rehabilitation and implant fatigue and wear were responsible for ligament failures.

Adult↗
PubMed1997

Bone morphogenetic protein-2 stimulates differentiation of cultured spinal ligament cells from patients with ossification of the posterior longitudinal ligament.

Ossification of the posterior longitudinal ligament (OPLL) of the spine is characterized by heterotopic bone formation occurring in spinal ligament, causing severe compression myelopathy. In order to investigate the mechanism of OPLL development, we isolated spinal ligament cells from OPLL patients as well as non-OPLL patients, and established 10 OPLL cell lines and 7 non-OPLL cell lines, respectively. We analyzed the effects of bone morphogenetic protein-2 (BMP-2) on these cells with respect to alkaline phosphatase (AP) activity, DNA synthesis, and collagen production. BMP-2 caused a significant increase of AP activity in 4 OPLL cell lines, whereas the activity did not change in any non-OPLL cells. Among OPLL cells, BMP-2 stimulated DNA synthesis in four cell lines and procollagen type I carboxyl-terminal peptide (PICP) synthesis in five cell lines. Some non-OPLL cells also responded to BMP-2, as there was an increase of DNA synthesis in three cell lines and PICP synthesis in one cell line. These data collectively indicate that BMP-2 preferentially induces osteogenic differentiation in OPLL cells rather than in non-OPLL cells. OPLL cells, therefore, exhibit a different response to BMP-2 than non-OPLL cells, suggesting that the expression of BMP receptor(s) and/or the signal transduction initiated by BMP-2 in the spinal ligament cells of OPLL patients somewhat deviate from those in normal spinal ligament cells. Such abnormal characteristics of OPLL cells as described here provide some clues to the clarification of the pathogenesis of OPLL.

Alkaline Phosphatase↗
PubMed2004

Anterior cruciate ligament graft impingement against the posterior cruciate ligament: diagnosis using MRI plus three-dimensional reconstruction software.

OBJECTIVE: The purpose of this study was to evaluate anterior cruciate ligament (ACL) impingement against the posterior cruciate ligament (PCL) with the knee in an extended position, which arthroscopy cannot detect. MATERIALS AND METHODS: Ten normal knees and 30 ACL-reconstructed knees were assessed using MR imaging. The three-dimensional reconstruction of the ACL, PCL, femur and tibia were carried out using commercially available three-dimensional reconstruction software. Anterior cruciate ligament impingement against the PCL was graded into three categories: Grade 1, some space between the ligaments; Grade 2, no space between the ligaments, and the reconstructed ACL ran straight; and Grade 3, the reconstructed ACL did not run straight. The angle of the reconstructed ACL against the tibial plateau was also measured. RESULTS: All normal knees were classified as Grade 1. The 30 reconstructed knees were classified as follows: Grade 1, 12 cases; Grade 2, 7 cases; and Grade 3, 11 cases. The mean angle of the Grade 3 reconstructed ACL knees was significantly more vertical against the tibia as compared with the Grade 1 knees (P<.05). The postoperative KT-2000 side-to-side difference of the Grade 3 knees (2.8+/-4.5 mm) was larger than that of the Grade 1 knees (0.2+/-1.7 mm) and Grade 2 knees (-0.6+/-2.2 mm), but no statistically significant difference could be detected between the three groups in the postoperative KT-2000 data. CONCLUSION: This method is useful to evaluate ACL impingement against PCL, which cannot be detected by conventional arthroscopy during the operation. The surgeon should pay careful attention to the coronal angle of the reconstructed ACL.

Adolescent↗
PubMed2003

Uniaxial cyclic stretch induces osteogenic differentiation and synthesis of bone morphogenetic proteins of spinal ligament cells derived from patients with ossification of the posterior longitudinal ligaments.

Ossification of the posterior longitudinal ligament of the spine (OPLL) is characterized by ectopic bone formation in the spinal ligaments. Mechanical stress, which acts on the posterior ligaments, is thought to be an important factor in the progression of OPLL. To elucidate this mechanism, we investigated the effects of in vitro sinusoidal cyclic stretch (120% peak to peak, at 1 Hz) on cultured spinal ligament cells derived from OPLL and non-OPLL patients. The mRNA expressions of alkaline phosphatase (ALP), osteopontin, bone morphogenetic protein (BMP)-2, BMP-4, and BMP receptors as well as ALP activity in cell layers and production of BMPs into the conditioned medium were significantly increased by cyclic stretch in OPLL cells, whereas no change was observed in non-OPLL cells. A stretch-activated Ca(2+) channel blocker, Gd(3+), the voltage-dependent L-type Ca(2+) channel blockers diltiazem and nifedipine, and Ca(2+)-free medium suppressed stretch-induced ALP activity, which suggests a role of Ca(2+) influx in the signal transduction of mechanical stress to the osteogenic response of OPLL cells. Our study provides first evidences that mechanical stress plays a key role in the progression of OPLL through the induction of osteogenic differentiation in spinal ligament cells and the promotion of the autocrine/paracrine mechanism of BMPs in this lesion.

Alkaline Phosphatase↗
PubMed2003

Avulsion fracture of the posterior oblique ligament associated with acute tear of the medial collateral ligament.

The term posterior oblique ligament was proposed in 1973 but the specific anatomy of this region has been controversial. It has been concluded that the posterior oblique ligament is separated from the medial collateral ligament, each with distinctly different bony attachment points. In this article, we report a posterior oblique ligament avulsion fracture associated with a medial collateral ligament rupture.

Accidents, Traffic↗
PubMed2002

Ligament grafts become more susceptible to creep within days after surgery: evidence for early enzymatic degradation of a ligament graft in a rabbit model.

Clinical evidence suggests that some ligament grafts stretch after surgery. Our purpose in this study was to quantify early postoperative creep behavior of ligament autografts in an animal model, and to explore potential mechanisms of that behavior. 38 New Zealand white rabbits underwent a unilateral, fresh, anatomic medial collateral ligament (MCL) autograft procedure and were killed immediately (time-zero), at 2 days, 3 weeks, or 8 weeks after surgery (n = 7-11 in each group). We compared the creep behavior of the autografts to normal MCLs (n = 8). An additional 7 MCL specimens were incubated for 2 days in a low concentration collagenase solution and then similarly creep-tested. All grafts were slower to recover their original length after creep than either normal ligaments or time-zero controls. These grafts started to become more vulnerable to elongation in cyclic and static creep tests within 2 days of surgery, compared to time-zero controls. This vulnerability to creep increased over the next 3 weeks, and was maintained at 8 weeks of healing. 2-day collagenase-soaked MCL specimens had the same creep strains as the 2-day autografts. These results suggest that even fresh anatomic ligament autografts become vulnerable to creep within a few days after surgery by mechanisms that may involve degradative enzymes such as collagenase.

Animals↗
PubMedDate not supplied

Tissue engineering of ligaments: a comparison of bone marrow stromal cells, anterior cruciate ligament, and skin fibroblasts as cell source.

Anterior cruciate ligament (ACL) reconstruction surgery still has important problems to overcome, such as "donor site morbidity" and the limited choice of grafts in revision surgery. Tissue engineering of ligaments may provide a solution for these problems. Little is known about the optimal cell source for tissue engineering of ligaments. The aim of this study is to determine the optimal cell source for tissue engineering of the anterior cruciate ligament. Bone marrow stromal cells (BMSCs), ACL, and skin fibroblasts were seeded onto a resorbable suture material [poly(L-lactide/glycolide) multifilaments] at five different seeding densities, and cultured for up to 12 days. All cell types tested attached to the suture material, proliferated, and synthesized extracellular matrix rich in collagen type I. On day 12 the scaffolds seeded with BMSCs showed the highest DNA content (p < 0.01) and the highest collagen production (p < 0.05 for the two highest seeding densities). Scaffolds seeded with ACL fibroblasts showed the lowest DNA content and collagen production. Accordingly, BMSCs appear to be the most suitable cells for further study and development of tissue-engineered ligament.

Animals↗
PubMedDate not supplied

Anterior cruciate ligament reconstruction with and without a ligament augmentation device : results at 8-Year follow-up.

BACKGROUND: Ligament augmentation devices have been used in anterior cruciate ligament reconstruction since the suggestion of Kennedy et al. in 1980 that such devices would allow grafts to heal faster and more safely. HYPOTHESIS: Patients who had augmentation will have better outcomes after 8 years. STUDY DESIGN: Prospective randomized case control study. METHODS: Between 1991 and 1993, 100 patients were randomized to groups undergoing anterior cruciate ligament reconstruction with bone-patellar tendon-bone grafts with (49) or without (51) use of a Kennedy ligament augmentation device. Of these 100 patients, 94 were examined at an average of 8 years after surgery. Fifteen patients were excluded because of rupture in the other knee and 11 because of rerupture in the same knee. RESULTS: Of the remaining 68 patients, the mean Lysholm function score was 84 in the augmentation group and 87 in the control group. There was a statistically significant relationship between preoperatively detected cartilage injury and osteoarthritis. Almost half of the patients had developed osteoarthritis. We observed no significant difference between the two groups concerning rerupture rate, Lysholm or Lachman test scores, or KT-1000 arthrometer measurements. CONCLUSIONS: We found no positive long-term effects supporting the use of augmentation in anterior cruciate ligament reconstruction.

Adolescent↗
PubMed1993

No effect of mop-ending on ligament healing. Rabbit studies of severed collateral knee ligaments.

We have tested the hypothesis that increasing the surface area of cut ligament ends by the creation of "mop-ends" may alter the mechanical properties of healing medial collateral ligaments. In one group of New Zealand white rabbits, a 4-mm midsubstance segment was removed from the right ligament creating a gap (sharp cut-end healing group). In the other group, a similar gap was created but, in addition, cut ligament ends were split longitudinally across the width of the ligament creating "mop-ends", roughly tripling the total injury surface area. In all animals, the contralateral (left) leg was not operated on and served as an internal control. At least 8 animals from each injury model were killed at 3, 6, 14, and 40 weeks post-operatively. Both histological and mechanical tests showed that sharp-cut and mop-end injuries healed at similar rates with similar material.

Animals↗
PubMed1997

Medial collateral knee ligament healing. Combined medial collateral and anterior cruciate ligament injuries studied in rabbits.

We examined the histological appearance and biochemical properties of the healing medial collateral ligament (MCL) of a rabbit knee after combined MCL and anterior cruciate ligament (ACL) injury treated with ACL reconstruction and with or without MCL repair. By so doing, we hoped to understand better our previous bomechanical observations (Ohno et al. 1995) and possibly learn where to focus future investigation into improving the quality of the healing MCL. Ligaments were examined at 6 and 12 weeks of healing. We found healing of all ligaments with hypercellularity and fibroblast elongation along the axis of loading, as expected. Unexpected, however, was the finding of multiple osteophytes in both the repaired and nonrepaired specimens at the medial borders of the joint and at the MCL insertions. These were felt to affect possibly the biomechanics of the MCL by causing stress risers at the point where they undermine the ligament. Biochemically, we demonstrated a correlation between collagen content and hydroxypyridinium crosslinks and modulus of elasticity. While this implies that the modulus is dependent on collagen content and hydroxypyridinium crosslink density, modulus is also probably dependent on other factors such as collagen organization, type and internal structure. Overall, the detailed characterization and correlation between the histological, biochemical, and biomechanical properties of the healing MCL in the severe knee injury model provide insight into the functional behavior of the healing MCL.

Animals↗
PubMed1997

Ligament creep cannot be predicted from stress relaxation at low stress: a biomechanical study of the rabbit medial collateral ligament.

In normal daily activity, ligaments are probably subjected to repeated loading rather than to repeated deformation. The viscoelastic response to repeated loading is creep; this effect has significance for ligament reconstructions, which potentially "stretch out" over time. However, most experimental studies have examined the viscoelastic response to repeated deformation, stress relaxation. We hypothesized that the creep of a ligament could be predicted from its stress-relaxation behaviour. Left and right medial collateral ligaments of eight skeletally mature rabbits were subjected to either creep or stress-relaxation testing under comparable conditions. The time-dependent increase in strain (creep) and reduction in load (relaxation) from the tests were modelled with use of the quasilinear viscoelastic theory and generalized standard linear solid modelling. Ligaments were found to creep distinctly less than would be predicted from relaxation tests. Although the reason for this behaviour remains unknown, we speculate that it is due to the progressive recruitment of collagen fibres during creep.

Animals↗
PubMed2006

Elastographic imaging of strain distribution in the anterior cruciate ligament and at the ligament-bone insertions.

The anterior cruciate ligament (ACL) functions as a mechanical stabilizer in the tibiofemoral joint, and is the most commonly injured knee ligament. To improve the clinical outcome of tendon grafts used for ACL reconstructions, our long-term goal is to promote graft-bone integration via the regeneration of the native ligament-bone interface. An understanding of strain distribution at this interface is crucial for functional scaffold design and clinical evaluation. Experimental determination, however, has been difficult due to the small length scale of the insertion sites. This study utilizes ultrasound elastography to characterize the response of the ACL and ACL-bone interface under tension. Specifically, bovine tibiofemoral joints were mounted on a material testing system and loaded in tension while radiofrequency (RF) data were acquired at 5 MHz. Axial strain elastograms between RF frames and a reference frame were generated using crosscorrelation and recorrelation techniques. Elastographic analyses revealed that when the joint was loaded in tension, complex strains with both compressive and tensile components occurred at the tibial insertion, with higher strains found at the insertion sites. In addition, the displacement was greatest at the ACL proper and decreased in value gradually from ligament to bone, likely a reflection of the matrix organization at the ligament-bone interface. Our results indicate that elastography is a novel method that can be readily used to characterize the mechanical properties of the ACL and its insertions into bone.

Animals↗