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PubMed2006

Denervation alters mRNA levels of repair-associated genes in a rabbit medial collateral ligament injury model.

Previous experiments revealed that denervation impairs healing of the MCL. This suggested the hypothesis that denervation would decrease repair-associated mRNA levels in the injured MCL when compared with normally innervated injured MCL. Adult, skeletally mature female rabbits were assigned to one of four groups: unoperated control, femoral nerve transection alone (denervated controls), MCL partial tear or denervated MCL partial tear. At three days, two weeks, six weeks or sixteen weeks post-surgery, cohorts of 6 rabbits from each experimental group were killed. Ligaments were harvested, RNA extracted and RT-PCR was performed using rabbitspecific primers. In the denervated injury group, mRNA levels for the angiogenesis-associated gene MMP-13, matrix components Collagen I and III, growth factor TGF-beta and angiogenesis inhibitors TIMP-3, and TSP-1 had all increased by two-weeks post-injury, in comparison to the non-denervated injury group (p < or = 0.01). An increased level of TSP-1 mRNA was also detected in the denervated injured group at sixteen weeks post injury (p < or = 0.01). Contrary to the initial hypothesis, denervation led to increased mRNA levels for many relevant molecules during the early stages of MCL healing. Thus, inappropriate timing of over-expression of some molecules may potentially contribute to the decreased quality of the scar tissue, particularly molecules such as TSP-1. Neuronal derived factors strongly influence the in vivo metabolic activity of ligament and scar fibroblasts in the initial phases of healing.

Animals↗
PubMed2004

Influence of collateral ligament laxity on patient satisfaction after total knee arthroplasty: a comparative bilateral study.

INTRODUCTION: Correct ligamentous balancing is an important determinant of the clinical outcome in total knee arthroplasty (TKA). Many surgeons prefer a tight rather than a lax knee during implantation of a TKA. The hypothesis in this study was that patients with a slightly laxer knee joint might perform better than patients with a tight knee joint after implantation of a TKA. PATIENTS AND METHODS: Twenty-two patients with bilateral knee arthroplasties were clinically and radiologically evaluated at a mean follow-up of 4.5 years, ranging from 2 to 7 years. There were 12 women and 10 men with an average age of 68.9 years (range 32-82 years) at the time of surgery. A modified HSS score (excluding laxity), varus and valgus stress X-rays in 30 degrees of knee flexion, and the subjective outcome of both knees were compared. A knee was considered tight when it opened less than 4 degrees and lax if it opened 4 degrees or more on stress X-ray. RESULTS: There was a trend towards improved range of motion and HSS score for the laxer knee joints. However, the difference did not achieve statistical significance. Eleven of the 22 patients considered one side subjectively better than the other side. In 10 out of these 11 TKA, the slacker knee joint was the preferred side ( p<0.05). CONCLUSIONS: As the present study compared bilateral knee joints after TKA, the same patient could act as a control group, and subtle subjective differences were revealed which are not quantifiable. The results showed that patients with a preferred side felt significantly more comfortable on the laxer side, indicating that during intraoperative ligamentous tensioning, some varus and valgus laxity at 20-30 degrees of flexion might be preferable to an over-tight knee joint. Further biomechanical and prospective investigations will be necessary to establish the correct soft-tissue tensioning.

Adult↗
PubMed1992

Ultrastructural morphometry of anterior cruciate and medial collateral ligaments: an experimental study in rabbits.

This study presents morphometric analyses of collagen subfascicle area fraction and collagen fibril diameter distributions for the anterior cruciate (ACL) and medial collateral (MCL) knee ligaments from transmission electron micrographs of ligament cross sections of five mature, female New Zealand White rabbits. Statistically significant differences in subfascicular area fractions were found between the ACL and MCL (0.89 +/- 0.02, 0.97 +/- 0.01, respectively; p less than 0.001). Mean fibril diameters for the ACL and MCL were also significantly different (0.059 +/- 0.005, 0.085 +/- 0.011 microns, respectively; p less than 0.025). Fibril eccentricity (a measure of parallel alignment of collagen fibrils within the ligaments, defined as the ratio of minor to major axes of elliptical fibril outlines) was 0.89 +/- 0.03 and 0.85 +/- 0.08, respectively, for the ACL and MCL; these data were not significantly different (p greater than 0.1). The relative amount of variation in the pooled fibril diameter data due to variation between animals, ligaments, locations within ligaments, and among fibrils at individual locations are reported. The variation of fibril diameter distributions between the ACL and MCL was substantially greater than the variation between different locations within each ligament cross section as well as between different animals. The structural differences reported may help explain known differences in the biomechanical properties of the ACL and MCL.

Animals↗
PubMed2006

Surgical treatment of acute lateral collateral ligament and posterolateral corner injuries.

Early surgical treatment of injuries to the posterolateral corner of the knee is recommended to promote rehabilitation for normal function of the knee. To optimize the chance at primary repair, surgery should be performed within 2 weeks; otherwise, reconstruction is the most viable option. During operative treatment, each component of the posterolateral corner is assessed individually, with primary repair performed if amenable to repair. Additional techniques, such as augmentation, advancement, or reconstruction may be needed if the primary repair is tenuous or the tissues damaged.

Collateral Ligaments↗
PubMed1984

Can carbon fiber implants substitute for collateral ligament?

The biomechanic and histologic changes following replacement of the medial collateral digit of the knee with carbon fiber filament prostheses of varying diameters were studied in young rabbits. Biomechanic testing showed changes with time in the mode of failure and force to failure of the replacements, but the initial differences in the force to failure of the three diameter groups diminished over the 12-week experimental period. Histologic studies with both light and electron microscopy revealed resorption of the carbon fibers and replacement by fibrosed ligaments. There was a correlation between the change in mode of failure and force to failure and increased production, orientation, and organization of new collagen fibrils, as well as simultaneous fragmentation of the carbon fibers.

Animals↗
PubMed2006

Physical examination and imaging of the lateral collateral ligament and posterolateral corner of the knee.

Diagnosis of posterolateral corner injuries can be challenging. Understanding the mechanism of injury in combination with careful history taking and a thorough physical examination are crucial. Clinical findings may be subtle, especially in the acute setting. Specialized tests such as external rotation recurvatum test, posterolateral drawer test, reverse pivot shift test, and dial test are particularly helpful. A characteristic radiographic finding is the arcuate sign, whereas medial Segond fractures can be associated with posterolateral corner injuries. Magnetic resonance imaging is most useful when performed with a high strength magnet utilizing a coronal oblique technique. Prompt and accurate diagnosis of posterolateral corner injuries allows the orthopedist to initiate the appropriate repair and reconstruction procedures to assure optimum treatment results.

Collateral Ligaments↗
PubMed1998

Temporal alterations in mRNA levels for proteinases and inhibitors and their potential regulators in the healing medial collateral ligament.

Wound healing in ligaments is a complex process which leads to functionally impaired scar tissue, even after extended time postinjury. To investigate the potential role of proteinases and inhibitors, as well as potential regulators of their expression, mRNA levels for collagenase, stromelysin, urokinase, PAI-1, and TIMPs 1 to 4 have been assessed by semiquantitative RT-PCR in RNA isolated from rabbit ligaments 3, 6, and 14 weeks postinjury. In addition, mRNA levels for IL-1, TNF, COX-2, and iNOS, potential regulators of proteinase/inhibitor expression, have been assessed. mRNA levels for the proteinases TIMP-1, -2, and -3 and PAI-1 were elevated early in scar tissue, but TIMP-4 mRNA levels exhibited a different pattern. In contrast, mRNA levels for the cytokines iNOS and COX-2 were either unchanged or depressed early after injury. The results indicate that alterations in mRNA levels for proteinases and inhibitors occurring early after injury are likely being influenced by factors other than IL-1, TNF, or products of COX-2 or iNOS.

Animals↗
PubMed2005

The healing rabbit medial collateral ligament of the knee responds to systemically administered glucocorticoids differently than the uninjured tissues of the same joint or the uninjured MCL: a paradoxical shift in impact on specific mRNA levels and MMP-13 protein expression in injured tissues.

The impact and molecular mechanism of action of glucocorticoids in connective tissues is largely unclear, even though widely used, and whether factors such as injury and inflammation modulate this response has not been elucidated. This study describes the role of glucocorticoids in the regulation of mRNA levels for collagens I and III, MMP-13, biglycan, decorin, COX-2 and the glucocorticoid receptor in connective tissues of normal and injured joints in an established rabbit in vivo MCL scar model, and examines the potential mechanism(s) involved. In vitro promoter studies were performed using an MMP-13 promoter-luciferase expression construct in transient transfection assays with a rabbit synovial cell line (HIG-82) to identify sites of glucocorticoid-mediated transcriptional regulation and the promoter elements involved. The in vivo results indicate that scar tissue from different phases of healing (early inflammatory, granulation tissue and neovascular, and later remodelling phases, respectively) displays a different pattern of responsiveness to glucocorticoid treatment than uninjured tissue and that this responsiveness is gene dependent. The most significant impact was seen for genes such as collagen I, collagen III and MMP-13, all of which are involved in connective tissue structure and remodelling. The in vitro studies confirmed the apparent in vivo glucocorticoid-mediated response of MMP-13 mRNA and implicated the AP-1 site of the MMP-13 promoter in this regulation. Immunohistochemistry studies showed increased MMP-13 protein expression, consistent with the mRNA findings, following glucocorticoid treatment in injured tissue but not normal tissues. In conclusion, connective tissue responsiveness to glucocorticoid treatment varies depending on injury and the stage of healing of the tissue, and consequently, glucocorticoid-responsiveness may be modulated differently in states of injury and inflammation.

Analysis of Variance↗
PubMed1985

[Descriptive anatomy and biodynamic study of the medial collateral ligament of the trapezio-metacarpal articulation of the thumb].

The trapezoid articular surface is classically compared to a saddle. The movements of the thumb obey to two centers of rotation. The one is proximal and determined by the convexity of the saddle; the other is distal and determined by its convexity. The authors have realised 15 dissections and 20 cinematic studies; they bring precision to the collateral medial trapeziometacarpal ligament and show the fundamental role of its anchorage point on the medial metacarpal tubercle: the distal center of rotation and the anchorage point are practically superimposed. The movements from this center are realised in indifferent pronosupination. The proximal center of rotation and the anchorage point are distant. The movements from this center are necessarily accompanied by pronation or supination. Statement report of the mechanism of this double rotation.

Biomechanical Phenomena↗
PubMed1986

Percutaneous accessory collateral ligament release in the treatment of proximal interphalangeal joint flexion contracture.

A percutaneous release or capsulo-ligamentous proximal interphalangeal joint contracture is described, the indications are outlined and the advantage over open releases are discussed. The results of a small pilot study are reported which we feel are comparable to the results of open techniques. The procedure in itself, however, merely allows operative correction to be achieved. Its maintenance depends upon a stringent post-operative rehabilitation regime.

Adult↗
PubMed2006

Outcome following conservative treatment of metacarpophalangeal collateral ligament avulsion fractures of the finger.

Avulsion fractures of the metacarpophalangeal joints are uncommon and there are few reports on their outcome after conservative treatment. We treated seven such patients with fracture fragment sizes between 10% and 25% of the width of the articular surface on the radiograph by early active mobilisation in neighbour strapping. The outcome of treatment was assessed at a mean follow-up of 57 (range 8-94) months. The mean visual analogue pain score was 0.6 (range 0-2) and the mean visual analogue function score was 9 out of 10 (range 6-10). The mean DASH score was 3.1 (range 0-12.5). All but one patient had normal grip strength and a full range of finger movement. We believe that the majority of avulsion fractures of the metacarpophalangeal joint can be managed successfully without surgery.

Adolescent↗