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PubMed1996

The differential adhesion forces of anterior cruciate and medial collateral ligament fibroblasts: effects of tropomodulin, talin, vinculin, and alpha-actinin.

We have determined the effects of tropomodulin (Tmod), talin, vinculin, and alpha-actinin on ligament fibroblast adhesion. The anterior cruciate ligament (ACL), which lacks a functional healing response, and the medial collateral ligament (MCL), a functionally healing ligament, were selected for this study. The micropipette aspiration technique was used to determine the forces needed to separate ACL and MCL cells from a fibronectin-coated surface. Delivery of exogenous tropomodulin, an actin-filament capping protein, into MCL fibroblasts significantly increased adhesion, whereas its monoclonal antibody (mAb) significantly decreased cell adhesiveness. However, for ACL fibroblasts, Tmod significantly reduced adhesion, whereas its mAb had no effect. mAbs to talin, vinculin, and alpha-actinin significantly decreased the adhesion of both ACL and MCL cells with increasing concentrations of antibody, and also reduced stress fiber formation and cell spreading rate as revealed by immunofluorescence microscopy. Disruption of actin filament and microtubule assembly with cytochalasin D and colchicine, respectively, also significantly reduced adhesion in ACL and MCL cells. In conclusion, both ACL and MCL fibroblast adhesion depends on cytoskeletal assembly; however, this dependence differs between ACL and MCL fibroblasts in many ways, especially in the role of Tmod. These results add yet another possible factor in explaining the clinical differences in healing between the ACL and the MCL.

Actinin↗
PubMed1996

The effect of removal of the medical collateral ligament on subchondral bone and cartilage in the growing rat knee joint.

The growing knee joint in immature rats was chosen as a model to study quantitatively bone apposition and thickness of articular cartilage after surgical removal of the medial collateral ligament. In 32 rats, subchondral bone apposition was assessed by measuring double tetracycline labelling, and the thickness of calcified and uncalcified articular cartilage was measured by image analysis. The results indicate that there was a significant increase in subchondral bone growth after removal of the medial collateral ligament, but no change in thickness of the calcified and uncalcified zones of the articular cartilage in the medial knee compartment. Further, despite an obvious increase in valgus laxity on manual examination, there were no signs of articular cartilage degeneration in any animal. The study shows that traumatic injury to ligaments and joint instability during the growing period may influence the development of subchondral bone in the knee joint.

Animals↗
PubMed1995

Selective muscle activation following electrical stimulation of the collateral ligaments of the human knee joint.

The objective of this study was to establish the presence of a local neurosensory reflex are from mechanoreceptors in human collateral ligaments and joint capsule to knee muscles and to determine if these muscles could be selectively activated as varus or valgus stabilizers using randomized trials. All studies were performed in the research department laboratories. Eleven subjects were recruited from the university staff and students based on no prior history of knee ailments. Subjects laid supine on an experimentation table as a current-modulated electrical stimulation was provided through the medial (MCL) or lateral collateral (LCL) knee ligaments. Latency of activation was measured for seven muscles, four by surface electrodes (semitendinosus, biceps femoris long head, vastus medialis, and lateralis), and three by intramuscular electrodes (sartorius, gracilis, tensor fascia lata). In the protocol, selective activation was defined as the relative increase in the activity of four muscles with medial moment arms following MCL stimulation compared with corresponding activity following LCL stimulation. For lateral muscles, the opposite was assumed (ie, that more activity would follow LCL than MCL stimulation). Monte Carlo simulations were performed on the data to determine significant selective muscle activation (p < .05). Statistically significant increases in activation were observed, most consistently, in the vastus medialis following MCL stimulation and in the vastus lateralis following LCL stimulation. These results suggest that a neurosensory reflex are from ligament mechanoreceptors may provide varus and valgus stabilization and knee muscles may be selectively activated to counter varus or valgus loads.

Adult↗
PubMed2006

Collateral ligament avulsion fractures from the heads of the metacarpals of the fingers.

Nineteen patients with collateral ligament avulsion fractures from the metacarpal heads of the fingers were treated during a 6 year period. Seven undisplaced fractures were initially treated conservatively. Four united with full movement. Three required internal fixation for symptomatic non-union and healed without problems. Eleven patients with displaced fractures were treated by primary internal fixation using a single lag screw through a dorsal approach. Seven of these achieved a full range of movement of the injured digit by 3 months. Four patients failed to regain full flexion of the metacarpophalangeal joint. One patient with a displaced and comminuted fracture was treated with internal fixation at 8 weeks when the fragment had consolidated. As with similar fractures from the proximal phalangeal bases, these fractures are prone to non-union when treated conservatively, even when undisplaced. If fixation becomes necessary, the delay of a trial of conservative treatment does not appear to affect the outcome. Internal fixation of displaced fractures allows gentle mobilisation and facilitates union.

Adolescent↗
PubMed2001

Structure and function of the healing medial collateral ligament in a goat model.

In this study knee joint function with a healing medial collateral ligament (MCL) at six weeks was examined with a robotic/universal force-moment sensor testing system during the application of two loading conditions: (1) 5 Nm valgus moment and (2) 67 N anterior load. Additionally the structural properties of the femur-MCL-tibia complex and the mechanical properties of the MCL substance were determined by uniaxial tensile tests. The histological appearance of the healing MCL was also observed. At 30 degrees and 60 degrees of knee flexion, valgus rotation of the healing knee was significantly increased compared to the sham. The in situ force in the healing MCL was significantly lower (34+/-17 N vs 54+/-12 N) at the same flexion angles (50+/-10 N vs 62+/-7 N). The anterior translation of the knee had returned to normal values at 30 degrees and 60 degrees of knee flexion. However, no differences could be found between the corresponding in situ forces in the healing MCL at all flexion angles examined during application of an anterior load. The stiffness of the healing group (52.5+/-19.4 N/mm) was significantly lower than the sham group (80.3+/-26.4 N/mm) (p<0.04). The modulus of the healing group was also significantly decreased (p<0.05). The findings suggest that the tensile properties of the healing goat MCL and valgus knee rotation have not returned to normal at six weeks after an isolated MCL rupture, however, anterior translation appeared to return to sham levels.

Animals↗
PubMed2003

A biomechanical and histological evaluation of the structure and function of the healing medial collateral ligament in a goat model.

This study evaluated the healing process of an isolated medial collateral ligament (MCL) rupture at 12 weeks in a goat model. Using a robotic/UFS testing system, knee kinematics in multiple degrees of freedom and in situ forces in the healing MCL in response to (1) a 67-N anterior tibial load and (2) a 5-Nm valgus moment were evaluated as a function of angles of knee flexion. Then a uniaxial tensile test of femur-MCL-tibia complexes (FMTCs) was preformed to obtain the structural properties of the FMTC and mechanical properties of the healing MCL substance. The histological appearance of the healing MCL was also examined for collagen and cell organization. The anterior tibial translation in response to a 67-N anterior tibial load was found to range from 1.9 to 2.4 mm, which was not significantly different from the sham-operated, contralateral control knee. In response to a 5-Nm valgus moment, however, MCL injury caused a 40% or more increase in valgus rotations over sham-operated controls for all angles of knee flexion tested. The magnitudes of the in situ forces in the healing MCLs for neither external loading conditions differed from sham-operated controls. For the structural properties of the healing FMTC, the stiffness returned to sham-operated control levels, but ultimate load at failure remained 60% of sham-operated control values. In terms of mechanical properties of the healing MCL, its tangent modulus and stress at failure were only 40% of sham-operated control values. Histologically, the collagen and cell organization at the femoral and tibial insertions as well as the midsubstance remained disorganized. Comparing these data to those previously reported at 6 weeks, there was a marked improvement in the in situ forces in the healing MCL and of the stiffness of the FMTC. Also, the data obtained for the goat model revealed a faster healing process than those for the rabbit model. These findings suggest that greater post-injury activity levels may render the goat to be a better animal model for studying the healing process of the MCL.

Animals↗
PubMed2004

Nonlinear viscoelasticity in rabbit medial collateral ligament.

The goal of this study was to characterize the viscoelastic behavior of the rabbit medial collateral ligament (MCL) at multiple levels of strain (between 0% and approximately 5%) and their corresponding stresses (between 0 and approximately 55 MPa) for stress relaxation and creep, respectively. We hypothesized that in the rabbit MCL the rate of stress relaxation would be strain dependent and the rate of creep would be stress dependent. Thirty MCLs from 15 rabbits were tested ex vivo for this study. Results show that within the physiologically relevant region of ligament behavior, the rate of stress relaxation is strain dependent in the rabbit MCL, with the rate of relaxation decreasing with increasing tissue strain. The rate of creep is stress dependent in the rabbit MCL, with the rate of creep decreasing with increasing stress. These results support our hypothesis, with the greatest nonlinearities in a physiologically relevant region of loading. As such, these nonlinearities should be considered when quantifying ligament viscoelastic behavior with a rabbit model.

Animals↗
PubMedDate not supplied

Acute Grade III ulnar collateral ligament ruptures. A new surgical and rehabilitation protocol.

A review is presented here of 36 cases, seen since 1980, of acute Grade III (unstable) sports-related sprains of the thumb metacarpophalangeal joint. In all cases, the injury involved the ulnar collateral ligament. A Stener lesion was present in 97% of cases. Followup was from 2.0 to 8.5 years, the average being 3.9 years. All of the patients underwent repeat examination and radiography at followup. The first seven patients were treated by "traditional" pull-out suture and K-wire fixation, put into a cast for 4 weeks, and then gradually mobilized over 4 additional weeks. Thereafter, a "new method" was used. Avulsed ulnar collateral ligament stumps were sutured to the tendinous insertion of the adductor pollicis or to a soft tissue remnant using strong suture material. Large bony avulsions were pinned; small fragments were excised and the ligament was repaired. This latter method of repair was quite strong and allowed rapid mobilization: only 2 weeks in a cast, then a hand-mounted thumb spica orthosis was used while therapy progressed. Of the patients treated with the new method, 84% had excellent results and, overall, were able to return to sports sooner than patients treated with the traditional method. Pain, stability, and strength were corrected equally between groups; however, strength was restored more rapidly in the new method group. Range of motion was reduced equally in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMedDate not supplied

Three-dimensional kinematics of ankle instability following serial sectioning of lateral collateral ligaments.

Triaxial kinematics of ankle instability were studied in vitro by applying an inversion force to seven nonaxially loaded cadaveric ankle-foot specimens. In intact specimens, mean maximal adduction of the tibia with respect to the calcaneus was 38 degrees and mean maximal external rotation was 24 degrees; maximal displacement occurred near full plantar flexion. Increases after release of ligaments were as follows: calcaneofibular, maximal adduction 10%, external rotation 3% near 15 degrees of plantar flexion; anterior talofibular, adduction 30%, external rotation 8% at 30 degrees of plantar flexion; both, adduction 41%, external rotation 65% near 0 degree of flexion; all three lateral collateral, adduction 42%, external rotation 240% in slight dorsiflexion. Regardless of the status of the lateral collateral ligaments, the talus adducted and externally rotated 18 degrees +/- 1 degree with respect to the calcaneus. Hence, collateral ligament release had no effect on subtalar motion.

Ankle Joint↗
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↗
PubMed2000

[Microangiographic evaluation of vascular supply of the medial collateral ligament of the knee joint].

Because the vascularization of ligaments is an important factor in ligament healing we wanted to examine the vascularization status of the medial collateral ligament of the knee. The type of vascularization was examined by microangiographie of 21 postmortem preparations. We could observe a vascularization from the proximal end of the ligament by one or two major vessels in all cases. These vessels were mostly localized in the ventral third of the ligament. From the proximal to the distal part of the ligament we found a decreasing density of blood vessels. We could not observe vessel free ligament areas. Due to this vascularization status we would advise the differentiation of two ligament areas respecting the following therapy. Because of the good vascularization in the proximal part of the ligament we can accept good conditions concerning complete healing after a non-operative treatment and an operative therapy by suture or refixation. In the case of interligamentous and distal ruptures operative reconstruction by sutures often in difficult and a conservative therapy leads to a high rate of poor results. Therefore we advise fibrin bonding in these ligament areas if a surgical procedure is indicated because of the high risk of vessel strangulation after suture.

Angiography↗
PubMedDate not supplied

Lateral collateral ligament avulsion of the humeroradial joint in a horse.

This report describes traumatic avulsion of the lateral collateral ligament of the humeroradial joint in a horse. The history and diagnostic procedures are included with relevant radiographs and ultrasonographs. The poor prognosis associated with this injury is due to degenerative joint disease.

Animals↗
PubMedDate not supplied

MRI of injury to the lateral collateral ligamentous complex of the ankle.

We retrospectively evaluated the lateral collateral ligamentous complex of 43 patients who had complained of ankle pain following ankle sprain. The MR signs of ligamentous abnormality included discontinuity or absence, increased signal within the ligament, and ligamentous irregularity or waviness with normal thickness and signal intensity. Using these criteria, 30 anterior talofibular, 20 calcaneofibular, and no posterior talofibular ligament injuries were diagnosed. Compared with surgery (nine patients), MRI demonstrated six of seven anterior talofibular ligament injuries and six of six calcaneofibular ligament injuries. Magnetic resonance showed ligamentous abnormalities in 12 of 23 cases with normal stress radiography. Magnetic resonance imaging provides useful information for the evaluation of patients presenting with chronic pain after ankle sprain.

Adolescent↗
PubMed1992

Ulnar collateral ligament injury in baseball pitchers: MR imaging evaluation.

The ulnar collateral ligament (UCL) provides stability to the medial aspect of the elbow during valgus stress. Trauma to this ligament may result from repetitive forceful throwing. Diagnosis of UCL injury has been based on clinical findings of medial joint pain and valgus instability, as direct imaging of this structure has not been available. Eleven baseball pitchers with clinical evidence of UCL injury were evaluated with magnetic resonance (MR) imaging. Surgical correlation was obtained in six patients, four of whom underwent UCL reconstruction. MR imaging findings in UCL injury included laxity, irregularity, poor definition, and increased signal intensity within and adjacent to the UCL. These findings reflect the presence of hemorrhage and/or edema within the UCL due to repeated microtears, which eventually lead to weakening and possible disruption of the UCL. Optimization of spatial resolution, signal-to-noise ratio, and other technical factors is critical for evaluation of the UCL due to its small size. MR imaging is useful in documenting the presence and severity of injury to the UCL and in distinguishing this entity from other causes of elbow pain.

Adolescent↗
PubMedDate not supplied

Medial collateral ligament replacement with a partially absorbable tissue scaffold.

The medial collateral ligaments and medial capsular structures of canines were resected and replaced with a carbon fiber-polylactic acid polymer tissue scaffold or allowed simply to "scar-in." After 4, 8, 12, and 26 weeks in vivo, the stability of the knees was quantitatively evaluated and the mechanical properties of the regrown structures determined. Histological sections of the regrown structures were examined after 26 weeks in vivo. At all time periods, the knees receiving tissue scaffold ligaments were significantly more stable than those knees allowed to stabilize with scar tissue. Initial strength, rapid ingrowth, and benign tissue reaction suggest this new composite material may be useful in the treatment of joint instability.

Animals↗
PubMed1997

Injuries to the Ulnar Collateral Ligament of the Thumb Metacarpophalangeal Joint.

Injuries to the ulnar collateral ligament of the metacarpophalangeal (MCP) joint of the thumb are relatively common. When an incomplete rupture is present, valgus stress testing with the MCP joint positioned in extension reveals minimal or no instability (less than 30 degrees of laxity or less than 15 degrees more laxity than in the noninjured thumb). When a complete rupture is present, valgus stress testing with the MCP joint positioned in extension reveals marked laxity (more than 30 degrees or more than 15 degrees more laxity than in the noninjured thumb). In this instance, displacement of the ligament proximal and superficial to the adductor aponeurosis, which is often termed a Stener lesion, is likely. Partial ligament injuries in which the ligament is not displaced may be treated nonoperatively. When a Stener lesion is present, however, primary ligament healing cannot occur without operative management. Whether treatment should be operative or nonperative can generally be decided on the basis of the findings from the history, the radiographs, and the physical examination, which should include valgus stress testing.

Journal Article↗