Adhesiveness of human ligament fibroblasts to laminin

The adhesiveness of fibroblasts from the human anterior cruciate and medial collateral ligaments to the laminin molecule was studied, with particular emphasis on the intrinsic differences between fibroblasts from the two ligaments. Cellular adhesion strength, adhesion area, laminin concentration, and seeding time were examined. Cell adhesion to laminin anchored with poly-D-lysine to a cleaned cover glass was measured with a micropipette micromanipulation system after seeding. The adhesion strength of fibroblasts from the anterior cruciate ligament to laminin was greater than and significantly different from that of fibroblasts from the medial collateral ligament, depending on the laminin concentration. Fibroblasts from the anterior cruciate ligament also exhibited an increase in adhesion strength, dependent on laminin concentration of as much as 30 micrograms/ml, at which the laminin receptors were thought to be saturated. Fibroblasts from the medial collateral ligament did not show such an increase except at laminin concentrations of 5-10 micrograms/ml. There was no significant difference in adhesion area between fibroblasts from the two ligaments except after 45 minutes at a laminin concentration of 40 micrograms/ml. For both, the adhesion to laminin showed little correlation to seeding time during periods of as long as 60 minutes. Measurements of adhesion area also failed to show a significant correlation to seeding time for fibroblasts from either ligament at laminin concentrations of 20 and 40 micrograms/ml. Adhesion strength normalized by adhesion area had no correlation to seeding time.(ABSTRACT TRUNCATED AT 250 WORDS)     

Anterior knee laxity and loss of extension after anterior cruciate ligament injury

This study was performed to examine the relationship between knee extension loss and the length of time after injury. We also wanted to compare anterior laxity in anterior cruciate ligament-injured knees in the early and late stages of injury. Loss of knee extension was measured in 81 patients with anterior cruciate ligament injury using lateral radiography with the injured leg relaxed and elevated. Extension loss was defined as the difference in maximal extension angle between the injured and uninjured knees. Average loss of extension was 3.6 degrees in the 17 knees in which the anterior cruciate ligament had been torn 3 weeks or less before examination (the acute injury group) and 0.6 degree in the 64 knees in which the anterior cruciate ligament had been torn more than 3 weeks before examination (the chronic injury group). The extension loss in the acutely injured knees was significantly greater compared with that in the uninjured knees and in the chronically injured knees. Arthrometric measurements using the KT-1000 arthrometer were reliable to diagnose an acute tear. There was no correlation between the degree of extension loss and arthrometric anterior knee laxity measurements. In 12 patients, the initial extension deficit in the early stage of injury significantly resolved with time, and manual maximum arthrometric measurements of anterior knee laxity improved spontaneously with time.     

Responses of mechanoreceptor neurons in the cat knee joint capsule before and after anterior cruciate ligament transection

It is known that afferent neurons play a protective role in knees made unstable by transection of the anterior cruciate ligament. However, it is not known whether cutting the anterior cruciate ligament has an effect on the response of the sensory neurons that innervate the joint. In this study, the responsiveness (activation threshold and position sensitivity) of single, mechanically sensitive afferent neurons from the cat knee was evaluated by a series of extension, internal, and external rotations. The anterior cruciate ligament then was cut and the same procedure was repeated. Transection of the ligament increased joint laxity for all types of rotation. The responsiveness of the neurons was not changed significantly by cutting the ligament (p > 0.05). Therefore, capsule afferents continue to behave normally in joints in which the anterior cruciate ligament has been transected.     

Meniscal injuries associated with acute anterior cruciate ligament tears in alpine skiers

We reviewed the records of 315 patients receiving an arthroscopically assisted stabilizing procedure for an acute anterior cruciate ligament injury incurred while alpine skiing to evaluate associated meniscal injuries. Meniscal injuries were classified by type, location, and treatment of the tear. Of the 317 knees operated on, all demonstrated an anterior cruciate ligament tear at arthroscopy. Ninety-eight percent of the injuries (310) were diagnosed within 3 days of injury, and 97% (307) were reconstructed within 28 days of injury. All tears occurred in the intrasubstance of the ligament; 32% were isolated injuries and 68% were combined with other injuries. In 159 patients with 170 meniscal tears 141 of the tears (83%) were lateral and 29 (17%) were medial. The injury triad of anterior cruciate ligament-medial collateral ligament-lateral meniscus was seen nine times as often as the anterior cruciate ligament-medial collateral ligament-medial mensicus combination.     

Acute repair of injury to the anterior cruciate ligament. A long-term followup

We reviewed 30 patients at an average of 7.4 years after acute repair of the anterior cruciate ligament augmented with a loop of iliotibial tract. A noncontact twisting had been the mechanism of injury in 18 of these patients, with 28 having been injured in sports. At followup, 25 patients had not experienced symptoms of instability and 23 were able to return to unrestricted athletic activity; only 5 had been unable or unwilling to return to sporting activity at all. There had been no swelling in 23 patients; however, 17 suffered from pain on exertion. The average Lysholm score was 93.2. Joint laxity was assessed and anteroposterior tibial translation quantified with a KT-1000 arthrometer. Eighteen patients had a normal or 1+ Lachman test and 27 had an absent or 1+ pivot shift. When compared with the results of a similar study performed on this group of patients at 2 years after surgery, there had been little subjective change in knee function. However, objectively there had been significant deterioration of the anteroposterior stability of the knees at 7 years, suggesting failure of the integrity of the repaired ligament with time. An associated medial collateral ligament injury had a significant adverse effect both on the integrity of the anterior cruciate ligament repair and the incidence of postoperative stiffness.     

The effects of an artificial meniscus substitute in a knee joint with a resected anterior cruciate ligament. An experimental study in rabbits

A Dacron meniscus prosthesis was substituted for the medial meniscus in an anterior cruciate ligament (ACL) resected rabbit knee. At three months, the joints were evaluated biomechanically, with gross and histologic inspection. In a paired comparison with the contralateral knee, differences between ACL resection with intact, incised, or resected medial menisci were evaluated. Knees with intact menisci and ligaments served as controls. Because of cartilage destruction, soft-tissue hypertrophy, and increased anterior laxity, joint stiffness was less than normal in all ACL-resected knees. Ingrowth and stable fixation, especially of the posterior horns of the prostheses and the incised menisci, were rare. Almost all normal menisci had ruptured in the same area. Anterior cruciate ligament resection led to severe osteoarthrosis in both compartments, regardless of initial meniscal treatment. Knees with prostheses had the same incidence and severity of osteoarthrosis as knees with meniscus resection. Anterior cruciate ligament resection alone induced excessive osteoarthrosis and synovitis and diminished the effects of different meniscal treatments three months earlier.     

Avulsion fracture of the anteromedial bundle of the anterior cruciate ligament

The avulsion fracture of the tibial attachment site of the anterior cruciate ligament is relatively rare among adults. Although partial avulsion fracture of this site is very rare, complex forces exerted on the knee joint could produce this type of fracture. We report on an adult patient with an avulsion fracture of the attachment site of anteromedial bundle of the anterior cruciate ligament associated with injuries of lateral and medial collateral ligament and fibular fracture. We speculate varus stress in a flexed knee coupled with rotation between the femur and tibia caused this type of injury.     

Effect of external extra-articular ligament plasty on the results of anterior cruciate ligament reconstruction with patellar tendon, a 4 years follow-up

PURPOSE OF THE STUDY: The purpose of this study was to compare the functional results obtained when an external extra-articular plasty was added to an anterior cruciate ligament (ACL) reconstruction using an autologous bone tendon-bone patellar tendon graft. MATERIAL AND METHODS: The authors analyzed two consecutive series of 60 and 50 patients operated by the same surgeon for a chronic rupture of the anterior cruciate ligament, one by reconstruction of the cruciate ligament with a free graft of the patellar tendon supplemented by an external extra-articular plasty made with a quadriceps tendon graft and the second with an isolated free patellar tendon graft. Anterior laxity was measured before and after surgery, by dynamic X-rays and by the Medmetric KT-1000 arthrometer. Functional results were evaluated four years after operation, with the French A.R.P.E.GE score based on sport activity level and intensity. RESULTS: Anterior laxity was not different before operation in both groups and there was no difference between males and females. Medmetric KT-1000 arthrometer showed the same negative differential laxity immediately after surgery in both groups and the same evolution during the first 4 years, without any significant difference on laxity on the middle aspect of the knee. Radiological results were different. After a 4 years follow-up, anterior laxity did not show significant difference on the medial compartment of the knee (5.3 +/- 2.3 mm and 5.5 +/- 1.7 mm), but there was a significant minor laxity in the lateral compartment for the lateral extra-articular plasty group (11.0 +/- 2.3 mm against 14.8 +/- 3.8 mm)(p = 0.002). Functional results and sport activity were similar in both groups. Examination showed 4 positive pivot shift tests (2 "sliding" and 2 positive) in the group with extra-articular plasty, even though 8 positive pivot shift tests in the isolated ACL group (5 "sliding" and 3 positive) were found. DISCUSSION: This study, as well as five others studies found in literature, was not randomized. In all these series, the surgical techniques, the rehabilitation programs and the functional score evaluation were too different to allow any pertinent comparison. Extra-articular plasty helps to control the laxity of the lateral compartment of the knee which is incompletely controlled by ACL reconstruction, particularly in chronic cases. This is proved by radiological measurements and pivot shift tests. Jensen in 1983, about 205 patients with a 4 year follow-up and Noyes, which used an allograft patellar tendon, found an advantage to do extra-articular plasty. But Strum (in 1989), as O'Brien (in 1991) and Roth (in 1987), did not found any advantage with extra-articular plasty. CONCLUSION: It is therefore obvious, after a four-year follow-up, that extra-articular supplementation presents an advantage for reconstruction of the ACL. by a free graft of the patellar tendon in chronic cases. Further randomized study will confirm that isolated ACL reconstruction is possible in some well defined categories of anterior laxity.     

Injury size affects long-term strength of the rabbit medial collateral ligament

Long-term effects (104 weeks) of 2 extremes of gap size on the mechanical behavior of the rabbit medial collateral ligament were examined. In the midsubstance of each right medial collateral ligament, either an 8 mm gap injury was created or a 4 mm Z plasty injury was created and repaired. Each group was subdivided into a healing interval of 40, 78, or 104 weeks. Femur-medial collateral ligament-tibia complexes were tested mechanically or examined with light microscopy. Both injuries healed with histologically similar tissue and showed improved mechanical behavior 78 weeks after injury. No further improvement was measurable 104 weeks after injury. Scar material properties remained markedly inferior to normal regardless of injury. Low load and viscoelastic behavior recovered relatively well regardless of gap size. However, gap injuries showed significantly inferior structural properties at all intervals. These results suggest that a large initial gap between ligament ends in the extraarticular space predisposes scars to long term structural weakness. If this principle is true clinically, then patients with large gaps between torn ligament ends (caused by displacement, folding, or retraction) may function well at lower loads, but they may be chronically at greater risk of reinjury at high loads.     

Periarticular heterotopic ossification: a complication of arthroscopic anterior cruciate ligament reconstruction using a two-incision technique

Extra-articular heterotopic bone formation was recognized as a postoperative complication of arthroscopic anterior cruciate ligament reconstructions in four knees around the femoral drill hole. Although laxity of the reconstructed anterior cruciate ligament was not observed in these patients, local pain, swelling, and deformity at the site of heterotopic ossification required surgical intervention. The ectopic bone can be successfully excised with restoration of function. The incidence rate of this complication is less than 1%.     

Tears of the medial collateral ligament: magnetic resonance imaging findings and associated injuries

For 23 patients with a surgically proven tear of the medial collateral ligament the findings from magnetic resonance imaging (MRI) of the knee were evaluated retrospectively. MRI revealed the tear in all cases, although when the injury was severe, distinguishing high-grade partial tears from complete tears was difficult. Physical examination had indicated a tear in 22 (96%) of the cases. A high prevalence of associated cruciate and meniscal injuries was seen (in 23 [100%] and 12 [52%] of the cases respectively). Tears of the fibular collateral ligament occurred in 13 (57%) of the patients and at least one bony infraction in 22 (96%); most of the infractions were in the lateral compartment. Infractions of the lateral femoral condyle were frequently geographic (in 14 [70%] of the 20 cases) or impacted (in 5 [25%]). The spectrum of injuries associated with tears of the medial collateral ligament was consistent with the findings of previous studies focusing on cruciate and meniscal abnormalities; the minor variations were likely due to the severity of valgus stress in this sample.     

Indications for surgical treatment of tibial condyle fractures

The residual radioanatomic changes influencing the functional, subjective, and clinical outcome of 131 tibial condyle fractures were studied. Clinical function was found to deteriorate rapidly with increasing values of residual medial tilt of the tibial plateau, whereas lateral tilt of the plateau was well tolerated up to 5 degrees. Articular step-off up to 3 mm and condylar widening up to 5 mm had no adverse effects. Seventy percent of knees with moderate or severe instability were functionally unacceptable. It was concluded that a medial unicondylar fracture with any displacement, and all medially tilted bicondylar fractures, should be operated upon. In fracture of the lateral condyle, open reduction and internal fixation is indicated when lateral tilt or valgus malalignment exceeds 5 degrees, articular step-off exceeds 3 mm, or condylar widening exceeds 5 mm. The same limits apply to laterally tilted bicondylar fractures, provided that the medial condyle is undisplaced. Any displacement seen in the axial bicondylar fracture is an indication for surgical treatment. If there is any mediolateral instability in the extended knee joint after rigid internal fixation, repair of a collateral ligament should be considered. An avulsed anterior cruciate ligament should be fixed, if pathologic laxity exists, but the torn ligament can be ignored and reconstructed later if needed.     

Wear patterns on tibial plateaus from varus and valgus osteoarthritic knees

The size and location of articular cartilage wear was assessed on 106 varus and 37 valgus osteoarthritic tibial plateaus resected during total knee arthroplasty. Anterior cruciate ligament integrity was assessed intraoperatively, and calibrated digital images were used to measure the wear patterns. Complete anterior cruciate ligament deficiency was seen in 25% of the varus and 24% of the valgus knees. Wear patterns on anterior cruciate ligament intact and attenuated varus tibial plateaus occurred in the middle to anterior aspect of the medial plateau. Anterior cruciate ligament deficient varus plateaus had significantly larger wear areas located more posterior on the medial plateau. In contrast, anterior cruciate ligament intact and deficient valgus tibial plateaus had wear located posterior to the center of the lateral plateau. Anterior cruciate ligament integrity is a discrete feature of advanced osteoarthritis that strongly influences the articular wear patterns. The anterior cruciate ligament deficient wear patterns show a wear mechanism that is consistent with the posterior femoral subluxation and posterior tibiofemoral contact observed after acute anterior cruciate ligament rupture. These observations provide insight into the altered knee mechanics that exist in osteoarthritic knees and the resulting mechanical factors that contribute to degenerative changes.     

Kinematics of the lateral ligamentous constraints of the elbow joint

Thirty osteoligamentous elbow joint specimens were included in a study of the lateral collateral ligament complex (LCLC). The morphologic characteristics of the LCLC were examined, and then three-dimensional kinematic measurements were undertaken after selective ligament dissections were performed. Isolated sectioning of the annular ligament (AL) or the lateral ulnar collateral ligament (LUCL) induced only minor laxity to the elbow joint with a maximum of 2.2 degrees and 4.4 degrees during forced varus and external rotation (supination), respectively. Transsection of the lateral collateral ligament (LCL) caused a maximal laxity of 15.4 degrees and 22.8 degrees during forced varus and external rotation (supination), respectively. Combined ligament dissections showed that total transection of the LCLC at the ulnar or the humeral insertion was important for joint laxity. Total transection of the LCLC at the humeral or the ulnar insertion induced a maximal laxity of 24.5 degrees and 37 degrees during forced varus and external rotation (supination), respectively. This study suggests the AL and the LUCL are of minor importance as constraints when cut separately, whereas the LCL is a significant preventer of elbow joint laxity. The LCLC was observed to be a complex structure of ligamentous fibers rather than discreet bands. The LCLC forms a ligamentous constraint between the lateral humeral epicondyle and the ulna, stabilizing the elbow joint and forming a base for radial head stability and rotation.     

A comparison of patellar tendon autograft and allograft used for anterior cruciate ligament reconstruction in the goat model

Similar-sized patellar tendon autografts and fresh-frozen allografts were used to reconstruct the anterior cruciate ligament of one knee in 40 female goats. Evaluations of the reconstructions and contralateral controls at the 6-week and 6-month postoperative periods included anterior-posterior translation, mechanical properties determined during tensile failure tests, measurement of cross-sectional area, histology, collagen fibril size and area distribution, and associated articular cartilage degenerative changes. Six months after anterior cruciate ligament reconstruction, the autografts demonstrated a smaller increase in anterior-posterior displacement, values of maximum force to failure two times greater, a significant increase in cross-sectional area, a more rapid loss of large-diameter collagen fibrils, and an increased density and number of small-diameter collagen fibrils compared to the allografts. Clinical significance. More surgeons are allowing their patients to return to running and sports 6 months after anterior cruciate ligament reconstruction. While the structural and material properties of autografts and allografts at time zero are similar, in the goat model during the first 6 months they differ. The allografts demonstrate a greater decrease in their implantation structural properties, a slower rate of biologic incorporation, and the prolonged presence of an inflammatory response. At 6 months the autograft demonstrates a more robust biologic response, improved stability, and increased strength to failure values.     

The effects of knee reconstruction on combined anterior cruciate ligament and anterolateral capsular deficiencies

We tested the effect of intraarticular reconstructions of the anterior cruciate ligament alone and in combination with extraarticular reconstructions in 10 cadaveric knees. These knees had anterior cruciate ligament deficiency alone or in combination with anterolateral capsuloligamentous deficiencies. In the knees with combined injury, intraarticular reconstruction returned anterior stability to levels not significantly different from levels found for the knees deficient in the anterior cruciate ligament alone and treated with this procedure. After intraarticular reconstruction, rotational stability of the knee with combined injuries failed to return to the levels seen in the knee with isolated anterior cruciate ligament deficiencies that underwent the same treatment. When a tenodesis with either 0 N or 22 N of tension was added to the intraarticular reconstruction in the knee with combined injuries, we found that excessive internal rotation significantly decreased at all angles of flexion, except at full extension with 0 N of tension. In addition, the extraarticular reconstruction with 22 N of tension in the tenodesis overconstrained the knee in internal rotation between 30 degrees and 90 degrees of knee flexion. The tenodesis with 0 N of tension overconstrained the knee at only 60 degrees and 90 degrees of flexion. These results suggest extraarticular reconstruction as an adjunct to the intraarticular operation for the knee with anterior cruciate ligament and anterolateral structural injuries. The results also suggest that the surgeon can affect anterior and rotational laxity by adjusting the tension in the tenodesis.     

Injuries of the medial collateral ligament and anterior cruciate ligament of the knee joint and Lemaire surgical functional treatment. Long-term outcome

The present paper reports the results of 112 extraarticular ligamento-plasties performed on the knee with the procedure proposed by Lemaire. The series includes isolated tears of the anterior cruciate and medical collateral ligament as well as combined tears of both ligaments. The clinical and radiological results with a mean follow-up time of 11.5 years are compared with the results obtained in a first assessment 8 years ago. Good clinical results are in contrast with increasing osteoarthrosis in 1/3 of the knees radiologically assessed. The operation for a torn anterior cruciate ligament should be performed as soon as possible to avoid secondary meniscal lesions with subsequent severe osteoarthrosis. Presence or absence of arthrotic signs in the X-rays mainly determine the long-term result after ligamento-plasties of the knee. The Lemaire plasties are well tolerated even by elderly still active people and need little postoperative care.     

The effect of immediate weightbearing after anterior cruciate ligament reconstruction

Immediate weightbearing has been advocated after anterior cruciate ligament reconstruction and is thought to enhance the return of quadriceps muscle activity and knee extension range of motion without jeopardizing graft integrity. This study examined the effect of immediate weightbearing after anterior cruciate ligament reconstruction on the return of vastus medialis oblique electromyography activity, knee extension range of motion, knee stability, physical examination, Lysholm score, and anterior knee pain. Forty-nine patients (24 men and 25 women) undergoing endoscopic central third patella tendon autograft reconstruction were randomized prospectively into two groups. Group 1 patients underwent immediate weightbearing as tolerated. Group 2 patients were kept nonweightbearing for 2 weeks. All measurements were taken before surgery, 2 weeks after surgery, and between 6 and 14 months (average, 7.3 months) followup. There was no effect of weightbearing on knee extension range of motion or vastus medialis oblique function at followup. In addition, knee stability was not compromised after surgery. Seven of 20 (35%) nonweightbearing patients and only two of 25 (8%) immediate weightbearing patients reported anterior knee pain at followup. Overall, immediate weightbearing did not compromise knee joint stability and resulted in a better outcome with a decreased incidence of anterior knee pain.     

A 2-year-old child with acute respiratory difficulty. Pneumomediastinum and subcutaneous emphysema due to foreign body aspiration

Using familiar anatomic references viewed during a standard arthroscopic evaluation, an arthroscopic Lachman test can help the surgeon identify anterior cruciate ligament deficiency. This test is especially useful in those patients where a false-negative report as a result of guarding, meniscal tears or other factors is suspected. Additionally, this test can be used after anterior cruciate ligament reconstruction to verify that the abnormal anterior laxity has been eliminated.     

Comparison of arthroscopic and open reconstruction of the anterior cruciate ligament. Early results

The purpose of this study was to determine in a prospective, randomized, blinded design whether arthroscopically assisted anterior cruciate ligament reconstruction offered any significant immediate or short-term advantages over traditional open reconstruction through a limited arthrotomy. Patients with a diagnosis of deficiency of the anterior cruciate ligament were randomly assigned to one of two treatment groups: the open group (limited open reconstruction) or the arthroscopic group (fully arthroscopic reconstruction). Postoperatively, both groups were treated identically. Intra- and postoperative observations included length of surgery, duration of hospitalization, and amount of pain medication. Follow-up evaluations were performed at 1, 6, 12, 16, 20, and 24 weeks to record crepitus, swelling, range of motion, ligament laxity, and thigh atrophy. Lysholm scores were obtained at the 16 and 24 week follow-ups. At 24 weeks, 86% of the open group and 89% of the arthroscopic group had good-to-excellent results. Intraoperative, postoperative, and follow-up findings indicated no statistically significant differences or relationships between the two groups in any of the variables measured, except that operative time was 13 minutes longer in the arthroscopic group (P < 0.001). The results do not substantiate a clinical advantage for either technique.