The effects of tibial rotation on posterior translation in knees in which the posterior cruciate ligament has been cut.

BACKGROUND: One of the most useful clinical tests for diagnosing an isolated injury of the posterior cruciate ligament is the posterior drawer maneuver performed with the knee in 90 degrees of flexion. Previously, it was thought that internally rotating the tibia during posterior drawer testing would decrease posterior laxity in a knee with an isolated posterior cruciate ligament injury. In this study, we evaluated the effects of internal and external tibial rotation on posterior laxity with the knee held in varying degrees of flexion after the posterior cruciate and meniscofemoral ligaments had been cut. MATERIALS AND METHODS: Twenty cadaveric knees were used. Each knee was mounted in a fixture with six degrees of freedom, and anterior and posterior forces of 150 N were applied. The testing was conducted with the knee in 90 degrees, 60 degrees, 30 degrees, and 0 degrees of flexion with the tibia in neutral, internal, and external rotation. All knees were tested with the posterior cruciate and meniscofemoral ligaments intact and transected. Repeated-measures analysis of variance was used for statistical analysis. RESULTS: At 30 degrees, 60 degrees, and 90 degrees of flexion, there was a significant increase in posterior laxity following transection of the posterior cruciate and meniscofemoral ligaments. At 60 degrees and 90 degrees of flexion, there was significantly less posterior laxity when the tibia was held in internal compared with external rotation. At 0 degrees and 30 degrees of flexion, there was no significant difference in posterior laxity when the tibia was held in internal compared with external rotation. CONCLUSIONS: After the posterior cruciate and meniscofemoral ligaments had been cut, posterior laxity was significantly decreased by both internal and external rotation of the tibia. Internal tibial rotation resulted in significantly less laxity than external tibial rotation did at 60 degrees and 90 degrees of knee flexion.

A comparison of preoperative imaging techniques for predicting patellar tendon graft length before cruciate ligament reconstruction.

Autogenous bone-patellar tendon-bone is commonly used as graft material for cruciate ligament reconstructions. If this type of graft is too long, graft fixation other than an interference screw may be required. If it is too short, selection of another type of graft may be necessary. If the length of the patellar tendon portion of the graft could be accurately predicted, preoperative planning could determine the adequacy of this graft and choice of fixation for the planned procedure. Using lateral radiographs with the knee flexed 30 degrees, standard magnetic resonance imaging, and magnetic resonance imaging with supplemental three-dimensional reconstructions, we measured the length of the patellar tendon in cadavers and then compared these measurements with the actual patellar tendon length measurements. Linear regression analysis resulted in r2 values of 0.80, 0.43, and 0.65 for lateral radiographs, standard magnetic resonance imaging, and magnetic resonance imaging with three-dimensional reconstructions, respectively. We concluded that lateral radiographs at 30 degrees of knee flexion are the most accurate predictors of patellar tendon length.

A biomechanical comparison of posterior cruciate ligament reconstruction techniques.

Most posterior cruciate ligament reconstruction techniques use both tibial and femoral bone tunnels for graft placement. Because of the acute angle the graft must make to gain entrance into the tibial tunnel, abnormal stresses are placed on the graft that could lead to graft failure. An alternative technique for posterior cruciate ligament reconstruction involves placement of the bone plug from the graft anatomically on the back of the tibia (inlay), preventing formation of an acute angle at the tibial attachment site. We used six pairs of human cadaver knees to compare the biomechanical properties of these two techniques. One knee from each pair underwent tunnel reconstruction while the other knee underwent inlay reconstruction. There was significantly less anterior-posterior laxity in the inlay group when compared with the tunnel group from 30 degrees to 90 degrees of knee flexion and after repetitive loading at 90 degrees of knee flexion. Evaluation of the grafts revealed evidence of mechanical degradation in the tunnel group but not in the inlay group. The inlay technique resulted in less posterior translation with less graft degradation than did the tunnel technique for posterior cruciate ligament reconstruction.

Intramuscular corticosteroid injection for hamstring injuries. A 13-year experience in the National Football League.

The purpose of this study was to assess the safety of intramuscular corticosteroid injection in selected, severe hamstring injuries in professional football players. Clinicians have been reluctant to use corticosteroid injections in or around muscle-tendon units because of concern of incomplete healing or rupture. We retrospectively reviewed the computer database of one National Football League team for all hamstring injuries requiring treatment between January 1985 and January 1998. We found that 431 players had suffered such injury. We developed a clinical grading system to identify hamstring injury severity and to stratify players for treatment. Fifty-eight players (13%) sustained severe, discrete injuries with a palpable defect within the substance of the muscle and were treated with intramuscular injection of corticosteroid and anesthetic. There were no complications related to the injection of corticosteroid. Only nine players (16%) missed any games as a result of their injury. Final examination revealed no strength deficits, normal muscle bulk and tone, and the ability to generate normal power. We believe that the grading system we developed can assist in selection of injury type for injection. Although lack of a control group limits statements of efficacy of injection, our impression is that intramuscular corticosteroid injection hastens players' return to full play and lessens the game and practice time they miss.

Isolated sectioning of the medial and posteromedial capsular ligaments in the posterior cruciate ligament-deficient knee. Influence on posterior tibial translation.

This study was undertaken to determine the contribution of various structures in the posterior cruciate ligament-deficient knee in resisting posterior tibial translation. With "isolated" injuries to the posterior cruciate ligament, the amount of posterior translation will decrease with the posterior drawer test as the knee is taken from neutral to internal tibial rotation. The present study was performed to conclusively determine the anatomic structure responsible for this clinical observation. The TestStar device was used to perform single-plane posterior drawer tests in 14 cadaveric knee specimens. The tests were performed with the knee in neutral tibial rotation and in 20 degrees of internal tibial rotation. The intact knee was tested and then the knee was tested after sequential sectioning of the meniscofemoral ligaments, the posterior cruciate ligament, the posteromedial capsule, and the superficial medial collateral ligament. With the knee in neutral rotation, posterior translation continued to increase as each structure was sectioned. With the knee in internal tibial rotation, posterior displacement was significantly less than in neutral rotation for each state until the superficial medial collateral ligament was sectioned; posterior translation was increased after its sectioning. Our data demonstrate that the superficial medial collateral ligament is the structure responsible for a decrease in posterior tibial translation in the posterior cruciate ligament-deficient knee.

Localized anterior arthrofibrosis (cyclops lesion) after reconstruction of the anterior cruciate ligament: MR imaging findings.

OBJECTIVE: A localized form of anterior arthrofibrosis, the so-called cyclops lesion, has recently been reported to be a significant cause of loss of knee extension after reconstruction of the anterior cruciate ligament (ACL) of the knee. The purpose of this study was to characterize the MR appearance of this lesion. SUBJECTS AND METHODS: Five patients who had arthroscopic verification of a focal nodule of fibrous tissue in the intercondylar notch anterior to the reconstructed ACL (the cyclops lesion) and who had an MR examination after ACL reconstruction but before repeat arthroscopy and excision of the cyclops lesion were included in this study. The MR images were evaluated for the presence of soft tissue in the intercondylar notch anterior to the reconstructed ACL. If present, this tissue was graded as 1, 2, or 3, depending on its anterior extent along the femoral condyle. RESULTS: MR images of all five patients showed abnormal soft tissue with signal characteristics consistent with fibrous tissue anterior to the reconstructed ACL in the intercondylar notch. The abnormal tissue was grade 2 or 3 in all patients. CONCLUSION: MR imaging shows soft tissue with signal characteristics consistent with fibrous tissue anterior to the reconstructed ACL in the intercondylar notch in patients with localized anterior arthrofibrosis. Although the sensitivity and specificity of MR imaging for the cyclops lesion are yet to be determined, visualization of such fibrous tissue on MR images in a patient with clinical symptoms suggestive of localized anterior arthrofibrosis may be helpful in confirming the diagnosis.

Prospective study of osseous, articular, and meniscal lesions in recent anterior cruciate ligament tears by magnetic resonance imaging and arthroscopy.

Fifty-four patients with anterior cruciate ligament tears that were arthroscopically reconstructed within 3 months of initial injury were prospectively evaluated. Patients with grade 3 medial collateral ligament, lateral collateral ligament, or posterior cruciate ligament tears were excluded. Eighty percent of our patients had a bone bruise present on the magnetic resonance image, with 68% in the lateral femoral condyle. Two of the latter findings--an abnormal articular cartilage signal (P = 0.02) and a thin and impacted subchondral bone (P = 0.03)--had a significant relationship with injury to the overlying articular cartilage. Meniscal tears were found in 56% of the lateral menisci and 37% of the medial menisci. A significant association was present between bone bruising on the lateral femoral condyle and the lateral tibial plateau (P = 0.02). Results of our study support the concept that the common mechanism of injury to the anterior cruciate ligament involves severe anterior subluxation with impaction of the posterior tibia on the anterior femur. Determination of the significance of bone bruising, articular cartilage injury, or meniscal tears will require a long-term followup that includes evaluation for arthritis, stability, and function. These 54 patients represent the first cohort evaluated in this ongoing prospective clinical study.

Stress fractures of the tarsal navicular. A case report.

In summary, the diagnosis of a tarsal navicular stress fracture should be entertained in the athlete with ill-defined midfoot pain. Technetium bone scans will often point the clinician in the right direction; biplanar CT scans will pin-point the diagnosis and can be invaluable in perioperative planning. Subsequent treatment, however, must be determined on a clinical rather than a radiographic basis.

Medial malleolar stress fractures in seven patients: review of the clinical and imaging features.

Stress fractures of the medial malleolus were discovered in seven patients, five male and two female subjects aged 16-34 years. All except one were involved in running and jumping athletic activities. Gradual onset of pain over the medial malleolus occurred with repetitive activity. Focal intense increased uptake in the medial malleolus was present on bone scans. Conventional radiography and computed tomography demonstrated the presence of subtle fissures at the junction of the medial malleolus and the tibial plafond, and well-circumscribed lytic lesions were also seen in three patients. Two patients developed a complete fracture of the medial malleolus. Stress fractures of the medial malleolus should be suspected in patients involved in athletic and/or unusual activities who have experienced persistent and unexplained pain over the medial malleolus. Bone scans and radiographs should be obtained for diagnostic purposes in these patients.

Posterior shoulder instability. Surgical versus conservative results with evaluation of glenoid version.

We conducted a retrospective study on 50 patients with recurrent posterior shoulder instability. Twenty-five patients were treated conservatively with a specific rehabilitation program strengthening the rotator cuff. The other 25 patients, who did not improve with rehabilitation, underwent surgical reconstruction, the majority of these being soft tissue repairs. Recurrence in the surgically treated group averaged 72% while that in the conservatively treated group was 96%. However, 50% of those patients treated surgically and 68% of those treated conservatively felt their symptoms were improved. In view of the high recurrence rate with soft tissue reconstruction, computed tomography scans were obtained to evaluate glenoid version. Those patients with posterior shoulder instability were found to have increased glenoid retroversion when compared to an uninjured population (P less than 0.05). Our conclusions based on this study were that 1) specific therapy in the form of rotator cuff strengthening should be the initial form of treatment in patients with posterior shoulder instability, 2) soft tissue surgery has a high rate of recurrence, 3) the return to sports is variable, 4) there appears to be an increased incidence of glenoid retroversion in this patient population, and 5) the incidence of posttraumatic arthritis is low.

Femoral shaft stress fractures in athletes.

Stress fractures of the femoral shaft in athletes occur most commonly in the proximal third of the femur. They can, however, also be found in the mid- or distal third. Conservative treatment is highly successful in healing these fractures without complications. Athletes can usually return to activity in 8 to 14 weeks. Recognition of the symptoms characteristic of these fractures (vague thigh pain, diffuse tenderness, no trauma) will assist early diagnosis. Early definitive diagnosis can be made by radionuclide scanning or later, by plain radiography, if symptoms have been present for a sufficient period. Diagnosis is not limited to novice runners since runners with significant mileage, or baseball or basketball players, can develop femoral shaft stress fractures.

Fractures about the knee in sports.

In a review of fractures about the knee in sports, we have emphasized that these are uncommon but not unseen injuries. Within the spectrum of each fracture type, and excluding motor vehicle injuries, the fractures are usually of the more benign type. The athlete can anticipate participating at his or her desired level of play after appropriate treatment and rehabilitation in most instances. As in any fracture treatment, rehabilitation of the athlete is extremely important and enhanced, when feasible, by early motion. As the AO Group espouses "life is movement, movement is life."