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PubMed1979

[Experimental studies on the biomechanics of the lateral ligaments of the knee joint].

Measurements of absolute strain and stress on collateral ligaments of human knees were made with two new measuring cells. The medial collateral ligament was found to have three functional different parts, the most important of which was the ventral. During motion of the knee, tensile forces amounted to about 20 N when the lateral ligament was in extension and the medial ligament in full flexion. Moments of abduction and adduction increased strain and stress manyfold.

Biomechanical Phenomena↗
PubMed1996

Quantitative comparison of soft tissue-bone interface at chondral ligament insertions in the rabbit knee joint.

At chondral ligament insertions the calcified fibrocartilage interdigitates deeply with the lamellar bone. The shape of this interface is formed under physiological loading conditions. For the purpose of morphological comparison between different ligament entheses in the rabbit knee, the number and frequency of interdigitations and thickness of calcified fibrocartilage were quantitated at the femoral insertion of the medial collateral ligament, both insertions of the cruciate ligaments, and the tibial insertion of the patellar ligament. Among the insertions, the femoral insertion of the medial collateral ligament showed the lowest frequency and depth of interdigitations at the soft tissue-bone interface, but had the thickest zone of calcified fibrocartilage. An inverse relationship was found at the insertion interface of the cruciate and patellar ligaments. The frequency and depth of interdigations at the bone-soft tissue interface at different chondral entheses seem to be related to the mechanical strength of the respective ligament; meanwhile it may be hypothesised that the thickness of the calcified fibrocartilage might be more related to the amount of motion which takes place at an insertion.

Animals↗
PubMed1995

Intrinsic properties of ACL and MCL cells and their responses to growth factors.

Different intrinsic properties of the constituent cells of the anterior cruciate ligament (ACL) and medial collateral ligament (MCL) have been proposed to be one of the factors in the differential repair mechanisms. We have found that the outgrowth of cells from rabbit ACL explants was slower than from MCL explants after 10 d. Growth curves of ACL and MCL cultures at both Passage numbers 2 and 6 showed a slower rate of proliferation of ACL cells than MCL cells (P < 0.005). The proliferative response of rabbit ACL and MCL cells to b-FGF and TGF-beta was also investigated. Both b-FGF and TGF-beta had no significant effect on cell proliferation of ACL and MCL cultures after 48 h. However, TGF-beta did have an inhibitory effect on thymidine incorporation, especially at concentrations greater than 1 ng.ml-1, while b-FGF stimulated thymidine incorporation in ACL and MCL in a dose-dependent manner. Differences in the cell morphology of the ACL and MCL cells grown in culture were seen also. Cells from Passages 3-6 demonstrated these differences more prominently, and phalloidin staining for actin showed that ACL cells appeared to have more intracellular actin fibers.

Animals↗
PubMed1999

Ligament tissue engineering using synthetic biodegradable fiber scaffolds.

Tissue engineering offers the possibility of replacing damaged human ligaments with engineered ligament tissues. Hence, we attempted to culture in vitro ligament tissues by seeding human anterior cruciate ligament (ACL) and medial collateral ligament (MCL) cells onto synthetic biodegradable polymer fiber scaffolds. The ACL and MCL cells readily attached to the scaffold fibers. These cells and their secreted matrix soon surrounded the scaffold fibers and bridged the gaps in between. Beginning at 2 weeks, portions of the scaffolds were completely filled with tissue matrix. By 5 weeks, the scaffolds became single bundles of tissue. Thus the cell/fiber system appears to be a viable system for culturing ligament tissues. Additionally, cell proliferation under mechanical and biochemical stimuli was studied for up to 4 days. Whereas mechanical stimulus and transforming growth factor enhanced proliferation, inflammatory agents (lipopolysaccharide and complement C5a) had a negative effect. This work can thus contribute to a sound strategy for culturing replacement ligament tissues in vitro.

Anterior Cruciate Ligament↗
PubMed1989

The dorsal carpal ligaments: their anatomy and function.

The dorsal carpal ligaments were studied in 50 embalmed wrists. The radial collateral ligament was thin and oblique. The distribution of the dorsal radio-carpal ligament varied and it was classified into four subtypes. Neither ulnar collateral ligament nor dorsal radio-ulnar ligament was isolated as a discrete structure: instead, there were confluent soft tissues on the dorso-ulnar aspect of the wrist. The dorsal radio-carpal ligament and the dorso-ulnar component of the triangular fibro-cartilage complex, as well as the fibrous septa and the extensor tendons, were found to be the most important stabilizers of the wrist dorsally.

Humans↗
PubMed2006

Effect of cyclic strain and plating matrix on cell proliferation and integrin expression by ligament fibroblasts.

The role of cell surface integrins in cell migration, proliferation, and attachment to matrix molecules is well known. Integrin-matrix interactions have been implicated in mechanotransduction and load transmission from the outside to the inside of the cell. In this study, the effect of cyclic strain on the cell proliferation, attachment, and expression of integrin subunits beta1, beta3, and alpha5 was determined in anterior cruciate ligament (ACL) and medial collateral ligament (MCL) fibroblasts grown on polystyrene, Type I collagen, laminin, elastin, and fibronectin. ACL fibroblast proliferation was not affected by growth substrate whereas MCL cells reached confluence more rapidly on fibronectin compared with collagen or polystyrene. Exposure to 5% cyclic strain resulted in a significant decrease in ACL and MCL fibroblast proliferation on fibronectin and Type I collagen. MCL cells showed a greater strain-dependent inhibition of cells grown on a fibronectin substrate than those grown on collagen. This matrix-dependent effect of strain on cell proliferation was not seen with ACL cells. Attachment of ACL and MCL fibroblasts was stronger to fibronectin compared with Type I collagen, laminin, and polystyrene. In the absence of applied load, the expression of beta1, beta3, and alpha5 subunits was not substrate dependent and the expression of beta1 and alpha5 integrin subunits was higher in MCL cells than ACL cells on all substrates. In contrast, the expression of beta3 integrin subunit was higher in ACL cells than MCL cells. In response to 5% strain, beta1, and alpha5 expression increased in all fibroblasts with MCL cells having a higher magnitude of expression. beta3 expression showed a 90% increase in response to load when grown on laminin for both MCL and ACL fibroblasts and demonstrated no change in expression on Type I collagen or fibronectin. The duration of applied strain from 2 versus 22 h had no effect on cell proliferation or integrin expression.

Animals↗
PubMed2006

Anatomy of the posterolateral aspect of the goat knee.

The purpose of this study was to determine the anatomy of the posterolateral aspect of the goat knee for future in vivo studies using a goat model to examine the natural history of posterolateral knee injuries. Twelve non-paired, fresh-frozen, adult goat knees were dissected to determine the anatomy of the posterolateral corner. The main posterolateral structures identified in the goat knee were the lateral collateral ligament, the popliteus muscle and tendon, popliteomeniscal fascicles, and the lateral gastrocnemius muscle. The lateral collateral ligament was extra-articular and coursed from its proximal attachment, located posterior and proximal to the lateral epicondyle, to its distal attachment on the lateral aspect of the fused proximal tibiofibula. The popliteus muscle attached to the medial edge of the posterodistal tibia, traveled anterolaterally, became intra-articular at its musculotendinous junction, and attached to the lateral femur just distal to the lateral epicondyle. Distinct popliteomeniscal fascicles attached the lateral meniscus to the popliteus muscle and tendon, and a fascial attachment from the musculotendinous junction of the popliteus muscle coursed to the lateral tibial plateau. This study provided information on the structures present in the posterolateral aspect of the goat knee and enhanced our understanding of their relationships to analogous structures in the human knee. This information is important to enable future development of potential models of the natural history of posterolateral knee injuries and also to test surgical techniques and the in vivo effects of these injuries on cruciate ligament reconstructions.

Animals↗
PubMedDate not supplied

Evaluation of the arthroscopic valgus instability test of the elbow.

Seven fresh-frozen cadaveric elbows were used to evaluate the extent to which the medial collateral ligament must be injured before arthroscopic evidence of valgus instability is seen, the amount of ulnohumeral joint opening that does occur after such an injury, and the elbow position that maximizes visualization of this opening. While visualizing the most medial aspect of the ulnohumeral joint arthroscopically through the anterolateral portal, we sequentially sectioned the medial collateral ligament complex until all of the medial ligamentous restraints were cut. A valgus load was applied after each incision, and the extent to which the ulnohumeral joint opened was measured. Ulnohumeral joint opening was not visualized in any specimen until complete sectioning of the anterior bundle was performed. After the anterior bundle was released, 1 or 2 mm of joint opening was present in all specimens. Complete release of the medial collateral ligament led to dramatic increases in medial joint opening in all seven specimens (4 to 10 mm). Varying the angle of elbow flexion from 15 degrees to 120 degrees revealed that visualization of the medial joint opening was best at 60 degrees to 75 degrees. Finally, forearm pronation increased ulnohumeral joint opening and supination decreased joint opening in all specimens. We found that the entire anterior bundle must be sectioned before measurable and reproducible medial joint opening can occur.

Arthroscopy↗
PubMed1997

Decrease in fibronectin occurs coincident with the increased expression of its integrin receptor alpha5beta1 in stress-deprived ligaments.

Stress deprivation secondary to immobilization leads to atrophic changes in periarticular soft tissues. The changes in ligaments include a disorganization of collagen and cellular ultrastructure with varied biochemical alterations resulting in a functionally weaker tissue. This study tests the hypothesis that alterations in fibronectin (Fn) and the expression of its integrin receptor alpha5beta1 in ligament fibroblasts accompany the extracellular matrix remodeling which occurs in stress-deprived knee ligaments. The left knees of eighteen New Zealand white rabbits were surgically immobilized in acute flexion. Fibroblasts within three nine week and three twelve week stress-deprived anterior cruciate ligaments (ACLs) and medial collateral ligaments (MCLs) demonstrated markedly increased immunostaining for the beta1 and alpha5 integrin subunits, as compared to fibroblasts in the contralateral unoperated control ligaments. The effects of stress deprivation on the concentration of Fn was measured by competitive ELISA on the remaining twelve rabbits. Decreases in Fn of 54.0 percent and 63.7 percent occurred in the ACL after nine and twelve weeks of stress deprivation when compared to contralateral controls. The MCL had less of a decrease, losing 37.7 percent and 41.7 percent at nine and twelve weeks, respectively. These results suggest an important role for the Fn-specific integrin receptor alpha5beta1 in remodeling stress-deprived periarticular ligamentous tissue, and the importance of maintaining normal stresses on periarticular ligaments to prevent the degradation of extracellular matrix components such as Fn.

Animals↗
PubMed1982

Dislocations of the proximal interphalangeal joints of the long fingers. Anatomo-clinical study and therapeutic results.

The authors report an anatomo-clinic study on dislocations of the PIP joint in order to point out the lesions and the adequate treatment. This study is composed of two parts: first an anatomoclinical study of 29 dislocations all of which were operated on principle after a clinical and radiographic examination. The second part is a complementary anatomical study of 20 cadaveric joints based on an analysis of the different stabilizing structures of the joint. The study showed that, in order to get a dislocation of the PIP joint, it is necessary that two stabilizing formations be damaged. There is a major lesion and a minor one. The major lesion is characteristic of the type of the dislocation. Anterior dislocations were very rare in this study. The major lesion is a rupture or desinsertion of the central slip of the extensor tendon and the minor lesion is a tear in the collateral ligament. The treatment must be surgical because of the major lesion of the extensor apparatus. Quite different from the anterior lesions are the posterior and the lateral dislocations. They are more frequent. Although they have some similarities, they are, in fact, very different from an anatomoclinical and a therapeutic point of view. In posterior dislocations the major lesion is a rupture of the volar plate. The minor lesion is a partial desinsertion of the collateral ligament. These dislocations are stable after reduction. According to the authors, the best treatment is orthopedic, with a partial immobilization preventing the last degrees of extension. The major lesion in lateral dislocations is a rupture or avulsion of the collateral ligament and the minor lesion is a partial tear of the volar plate. After reduction they are unstable, and thus justify, according to the authors, an operative treatment, especially as they are often associated with cartilaginous lesions.

Adult↗
PubMed2000

The medial approach for operative release of post-traumatic contracture of the elbow.

We treated post-traumatic contracture of the elbow in 13 consecutive patients (14 elbows) by operative release. Through a single medial approach, the posterior oblique bundle of the medial collateral ligament was resected, followed by posterior and anterior capsulectomies. An additional lateral release through a separate incision was required in only four elbows. The results were assessed at a mean interval of 57 months after operation. Before surgery active extension lacked 43 degrees which improved to 17 degrees after operation. Active flexion before operation was 89 degrees, which improved to 127 degrees. The mean arc of movement increased from 46 degrees to 110 degrees. All 14 elbows showed scarring of the posterior oblique bundle of the medial collateral ligament. Neither the interval from injury to operative release nor the age of the patient affected the results. A medial approach is useful to reveal and excise the pathological changes in the medial collateral ligament. It is a safe and effective route through which to correct post-traumatic contracture of the elbow.

Adolescent↗
PubMed1999

Characterization of chemotactic migration and growth kinetics of canine knee ligament fibroblasts.

Migration and proliferation of ligament fibroblasts are essential for the healing of ligament injuries. This study was designed to evaluate the migration of intraarticular (anterior and posterior cruciate) and extraarticular (medial and lateral collateral) ligament fibroblasts in response to cytokines and to determine the effect of cell passage on cell proliferation. Recombinant human platelet-derived growth factor, hepatocyte growth factor/scatter factor, and bone morphogenic protein-2 stimulated the migration of all ligament cells in a dose-dependent manner, with optimal migration at 10 ng/ml. Recombinant human epithelial growth factor preferentially stimulated the migration of intraarticular ligament fibroblasts, whereas recombinant human interleukin-1 was more effective with extraarticular ligament fibroblasts. Recombinant human insulin-like growth factor-1, insulin-like growth factor-2, transforming growth factor-beta, and fibroblast growth factor had no significant effect on the migration of ligament-derived fibroblasts. These data suggest that specific cytokines stimulate the migration of knee ligament fibroblasts and provide a rationale for possible therapeutic approaches to optimize ligament healing. Fibroblasts derived from the anterior cruciate ligament have been shown to proliferate at a slower rate than those derived from the medial collateral ligament. We have extended these observations and have demonstrated that fibroblasts from both the posterior and anterior cruciate ligaments proliferate at a slower rate than lateral and medial collateral ligament-derived fibroblasts. The differences between the growth rates of intraarticular and extraarticular fibroblasts become insignificant with serial passaging of the cells.

Animals↗
PubMed2000

Rehabilitation after posterolateral dislocation of the elbow in a collegiate football player: a case report.

OBJECTIVE: To describe a functional rehabilitation program for a football player with a grade 2 posterolateral elbow dislocation to facilitate early return to competition. BACKGROUND: Conservative management of a posterior dislocation of the elbow is common. The elbow is the second most frequently dislocated large joint in adults. Two common mechanisms of dislocation are hyperextension and posterolateral rotation. Prolonged immobilization can be detrimental to regaining full range of motion and function of the elbow, whereas early directed rehabilitation may lead to early return to normal function. DIFFERENTIAL DIAGNOSIS: Elbow dislocation with medial collateral ligament rupture, elbow subluxation, elbow dislocation with neurovascular compromise, or supracondylar fracture. TREATMENT: The athlete received immediate care of reduction and immobilization in a 90 degrees posterior splint followed by a radiologic evaluation. Postreduction treatment included a short immobilization period and early initiation of protected active and resistive range-of-motion exercises. The athlete was able to return to full football activities in 3 weeks. He competed for the rest of the season with the elbow braced and taped, with no recurring incidents of instability. UNIQUENESS: The time to return to full participation was rapid. The medial collateral ligament was intact, as determined by magnetic resonance imaging. The athlete has since been followed for 2 football seasons and has not demonstrated any detrimental effects due to his early return. CONCLUSIONS: Early determination of the status of the medial collateral ligament through physical examination or imaging combined with early directed rehabilitation of a posterolateral elbow instability enabled this athlete to respond well. He regained pain-free full range of motion, strength, and function, allowing full participation in football at the Division I level with no recurring incidence of dislocation.

Journal Article↗
PubMedDate not supplied

A multivariate risk analysis of selected playing surfaces in the National Football League: 1980 to 1989. An epidemiologic study of knee injuries.

This study focuses on the injury rates for natural grass and AstroTurf surfaces and the risk factors of game position and type of play. We examined the game-related knee sprains, medial collateral ligament sprains, and anterior cruciate ligament sprains that occurred in the National Football League during the 1980 to 1989 seasons. The findings are controlled for categories of severity (number of games missed due to injury), position, and situation (rushing or passing) at the time of injury. The analysis of the data incorporates epidemiologic techniques associated with incidence density ratios. The data show that there is a statistically significant difference between the higher AstroTurf injury rates for knee sprains. When knee sprains are separated into medial collateral ligament sprains and anterior cruciate ligament sprains, only the anterior cruciate ligament sprains show a statistically significant higher injury rate for AstroTurf. When simultaneous control variables are considered, significantly more knee sprains occurred to backs on rushing plays and linemen on passing plays. When controlling the data for severity, only the Category II injuries (three or more games missed) sustained by linemen on passing plays had statistically significant higher injury rates for the AstroTurf. For medial collateral ligament sprains, only the Category II injuries for linemen on passing plays remain statistically significant. The data for the ACL sprains show statistically significant differences between the injury rate on natural grass and the injury rate on Astro Turf under conditions of special teams play.

Adult↗
PubMed2006

Intra-articular protrusion of malpositioned Transfix implant following anterior cruciate ligament reconstruction.

We report on a case of stiffness of the knee following reconstruction of the anterior cruciate ligament caused by a Transfix implant (Manufacturer, City, State) protruding into the medial retinacular area. After a skiing injury, a 56-year-old woman had a complete rupture of the anterior cruciate ligament along with a tear of the medial collateral ligament. She had an immediate anterior cruciate ligament reconstruction. A hinged brace was put on postoperatively. She presented to this institution 2 months after surgery with pain, stiffness, and decreased range of motion. Magnetic resonance imaging showed protrusion of the bioabsorbable implant in the medial retinacular area. Scar tissue was seen around the tip of the implant, medial retinacular area, and in the medial gutter. The terminal end of the protruding screw and the excess of scar tissue were removed arthroscopically. At the end of surgery, her on-table range of motion of the knee was 0 degrees to 120 degrees. She recovered well after physiotherapy and at the 3-month follow-up she was pain free and had virtually full flexion. The knee seemed stable and the medial collateral ligament showed signs of healing. Caution has to be exercised in the choice of size and angle of insertion of the Transfix implant.

Anterior Cruciate Ligament↗
PubMed1987

Acute surgical repair of the skier's thumb.

Complete ulnar collateral ligament tears incurred during the period fall 1977 through spring 1979 were treated under regional anesthesia by a single group of surgeons in an identical fashion as outpatients. Of 123 thumbs repaired, 69 (59%) were available for follow-up examination. There were 34 women and 35 men with an average age of 34.5 years (range, 16-61 years). The follow-up period averaged 31.6 months (range, 16-46 months). Weakness of pinch was described as none or mild in 66 (96%) and significant in only three (4%). Stiffness was described as none or mild in 66 (96%), moderate in two (3%), and severe in one (1%). Pain was described as none or mild in 68 (99%) and moderate in one (1%). Sixty-two patients (90%) preferred outpatient surgery with regional anesthesia whereas only seven (10%) did not. Forty-five (65%) of the 69 patients who required surgery had used traditional poles with straps, suggesting the pole as the causative factor. However, only 20% of noninjured skiers during the 1981-1982 season were using traditional poles with straps, and the total number of complete ulnar collateral ligament repairs did not decrease with the same number of skiers. Therefore, the change in pole design has not decreased the incidence of total ulnar collateral ligament tears. The results of acute surgical repair as an outpatient with regional anesthesia are excellent; 96% of the patients were pleased with the results. If the lesion is overlooked, the results of secondary construction are not nearly as good.

Adolescent↗
PubMed1999

The effect of medial release on flexion and extension gaps in cadaveric knees: implications for soft-tissue balancing in total knee arthroplasty.

This cadaver study examined the effects of medial structure release for varus deformity correction during total knee arthroplasty. Twelve specimens were used to investigate the amount of varus correction achieved with sequential release of medial structures. Varus-valgus and internal-external rotation angles were measured using the Isotrack II motion tracking system. Each release sequence was tested at full extension and 45 degrees and 90 degrees of flexion to compare any differences obtained in the joint gaps. After release of the posteromedial capsule oblique ligament complex, superficial medial collateral ligament (MCL), pes anserinus, and semimembranosus tendons, valgus rotation increased to 6.9 degrees in full extension and 13.4 degrees in 90 degrees of flexion. The largest increase (3.2 degrees) in valgus rotation occurred after the superficial MCL was released. Initial release of the superficial MCL led to a more gradual correction with release of subsequent structures. Changes seen in 90 degrees flexion were significantly greater than those in full extension. While the cadaveric model is limited by the lack of deformity in the specimens, the data provide several clinically relevant conclusions. In many cases requiring major medial release for severe varus deformity, potential flexion-extension differences in the resulting tibiofemoral gaps may require new consideration. These data may help explain the heightened interest in and variety of approaches for addressing femoral component rotation and issues of flexion stability since a significantly larger correction is obtained in flexion. Minimal changes in internal-external rotation of the tibia occurred until both the pes anserinus and semimembranosus tendons were released (4 degrees of external rotation).

Aged↗
PubMed1984

Surgical treatment of ligamentous instability after total knee arthroplasty.

During the period of January 1, 1972 through October 31, 1982 seven knees in seven patients had ligamentous reconstructions for instability following total knee arthroplasty. The type of ligamentous instability included severe medial instability in six and a combined severe medial and mild lateral instability in one patient. The surgical technique utilized to reconstruct the ligaments included proximal and distal advancement of the medial collateral ligament. In five of the seven, additional soft tissue surgery was combined with tightening of the medial collateral ligament. Unfortunately, ligamentous reconstruction failed to restore stability to the knee in any of the seven patients. Four patients required revision total knee arthroplasty. Instability of the knee necessitated full-time support with a brace and the seventh patient manages his instability without a brace. Ligamentous reconstruction without component revision is inappropriate in the treatment of the unstable knee following total knee arthroplasty.

Adult↗