Evaluation of the medial soft-tissue restraints of the extensor mechanism of the knee.

We performed an anatomical dissection of the medial soft-tissue retinacular fibers that restrain lateral patellar displacement and found that the medial patellofemoral ligament inserts not only on the patella but also on the undersurface of the distal aspect of the quadriceps mechanism. The deep capsular layer contained substantial retinacular fibers that were associated with the medial patellomeniscal ligament. Functional studies of the relative contributions of the medial soft-tissue restraints in the prevention of lateral patellar displacement were also performed. Twenty-five fresh-frozen specimens of the knee, obtained after amputations (nineteen specimens) or from cadavera (six specimens) were tested biomechanically on a universal testing instrument. We ranked the soft-tissue restraints, in order of their relative contributions to the restraining force, on the basis of the percentage of force provided by the retinacular and ligamentous tissue that resisted the lateral displacement of the patella. The medial patellofemoral ligament, although varying in size and importance, was found to be the major medial soft-tissue restraint that prevented lateral displacement of the distal knee-extensor mechanism, contributing an average of 53 per cent of the total force. The patellomeniscal ligament and associated retinacular fibers in the deep capsular layer of the knee, which were previously thought to be functionally unimportant in the stabilization of the patella, contributed an average of 22 per cent of the total force. The previously described retinacular fibers (the patellotibial band) were functionally unimportant in the prevention of lateral displacement.

Results of arthroscopic debridement of glenoid labral tears.

We studied the long-term results of a prospectively selected group of 24 patients with 12 anteroinferior and 12 posterior glenoid labral lesions; all patients had functional instability but none had ligamentous detachment. After arthroscopic debridement, patients involved in throwing sports were not allowed to return to full athletic activity until full strength of the external rotators was achieved and documented on isokinetic evaluation. Followup was 36 to 72 months with an average of 48 months. Follow-up isokinetic evaluation revealed an average +4.4% and +8.6% concentric strength and -4.3% and -0.4% eccentric strength of the operated shoulder compared with the uninvolved shoulder at 90 and 180 deg/sec, respectively. Long-term good or excellent results were achieved in 21 patients, and 16 were functioning at their preinjury level of sports activities. Sixty-two percent of baseball pitchers were unimpaired in pitching. The average University of California Los Angeles shoulder rating score was 31 of 35 (11 excellent, 10 good, and 3 poor) and the average Rowe-Zarins ratings scale was 85 of 100 (8 excellent, 13 good, and 3 poor). These results justify an initial arthroscopic debridement of anteroinferior or posterior labral flap tears rather than capsulorrhaphy when there is no gross instability or Bankart lesion.

Evaluation of claw toe deformity, weakness of the foot intrinsics, and posteromedial shin pain.

Posteromedial middle one-third tibial pain and tenderness associated with stressful activities has been previously recognized as occurring at the origin of the flexor digitorum longus muscle. Seventeen running athletes with this clinical syndrome were evaluated with regard to second toe range of motion and foot intrinsic muscle strength. The results were compared to results obtained from a comparable group of asymptomatic athletes. Statistical analysis of the results of the evaluation indicated a significant displacement of the arc of motion of the second toe in the symptomatic athletes toward extension of the metatarsophalangeal joint and a decrease in flexion. Weakness or dysfunction of the intrinsic muscles in the symptomatic athletes was also found to be significant. This analysis supports the hypothesis that posteromedial middle one-third tibial stress symptoms may be related to overuse of the flexor digitorum longus muscle associated with mild claw toe deformity.

The lateral notch sign associated with acute anterior cruciate ligament disruption.

We prospectively studied all of the patients with anterior cruciate ligament disruptions who sought treatment at the senior author's office during a 36-month period. Plain radiographs identified depressions measuring 2 mm or more in the lateral femoral condyle (lateral notch sign) in 9 of 120 knees (7.5%) with acute anterior cruciate ligament disruption and in 2 of 44 knees (4.5%) with chronic pivot shift instability. The depression ranged from 2 to 6 mm deep and from 20 to 25 mm long. The mean age for acutely injured patients with lateral notch signs was 17.2 years, 6 years younger than the mean age of the group with acutely injured anterior cruciate ligaments as a whole. Ten of the 11 patients (91%) with lateral notch signs were men, and all 6 patients with depressions shallower than prior descriptions of the notch sign were men. In contrast, 67% (N = 110) of the entire group of patients who had anterior cruciate ligament disruption were men. Ten of the 11 patients (91%) with the lateral notch signs and 4 of the 6 patients (66%) with minimal depressions also had lateral meniscus tears, while 58 of 147 patients (39%) without lateral femoral condyle depression had lateral meniscus tears. Previous reports that the lateral notch is a sign of chronic anterior cruciate ligament deficiency with recurrent pivot shifts are not supported by the number of prospectively recognized acute lateral femoral notch signs in this series. We found the presence of radiographic changes in the lateral femoral condyle to have statistically significant correlations with young age, male sex, lateral meniscus tears in general and anterior-horn lateral meniscus tears specifically, and lateral femoral chondral lesions.

Functional treatment of patellar dislocation in an athletic population.

Fifty-eight athletically active study participants with 69 knees that had experienced patellar dislocations were available for followup after being selected for a functional rehabilitation program without antecedent immobilization. Follow-up evaluation was at a minimum of 24 months after onset of treatment and averaged 46.2 months. Good or excellent results occurred in 39 (66%) knees treated after an initial patellar dislocation and in 15 (50%) knees with a chronic history of patellar instability. Twenty-six percent of the 69 knees had experienced recurrent patellar instability at followup. Overall, 42 patients (73%) were satisfied with their knees after this nonsurgical management. Anatomic predisposition and onset of bilateral instability at an early age were found to be significant factors associated with a less favorable outcome.

The effects of graft rotation on attachment site separation distances in anterior cruciate ligament reconstruction.

We created a model to see if twisting the graft in an anterior cruciate ligament reconstruction affected the distance separating the femoral and tibial attachments of the perimeter fibers of a patellar tendon graft. Graft bone plugs were simulated by two 12.5-mm diameter Delrin cylinders. Holes, 1 mm in diameter, were placed at the four corners of a centralized rectangle measuring 5 by 10 mm. Graft ligament fibers were represented by color-coded sutures passed through the holes in the modeled bone plugs. This graft model was fixed in tunnels reamed under arthroscopic guidance at the anterior cruciate ligament attachment sites of the femur and tibia in six fresh-frozen knee specimens. Spring gauges were used to measure indirectly the changes in distance of separation during knee flexion between the femoral and tibial attachments relative to a zero defined at 90 degrees of knee flexion. The tibial cylinder was rotated at 45 degrees increments from 90 degrees external to 180 degrees internal rotation relative to the femoral cylinder and measurements were repeated after each incremental rotation. External rotation resulted in a statistically significant higher mean separation distance (4.5 mm) for peripheral graft attachments than internal rotation (2.8 mm) (P = 0.05).

Occult anterior subluxations of the shoulder in noncontact sports.

Athletes participating in noncontact sports involving abduction and external rotation of the shoulder (e.g., throwing) may develop occult recurrent subluxation manifested only as pain. The lack of contact trauma preceding symptoms, the failure of the athlete to appreciate the instability, the relative rarity that the lesion has been previously recognized and reported, and the lack of objective evidence of instability often lead to incorrect diagnosis by the physician. We report 30 shoulders in 28 patients with this lesion. Nineteen of these patients had been originally seen by other physicians prior to presenting to us and misdiagnosed. The newly described apical oblique roentgenographic projection revealed Hill-Sach's lesions in 23 of 28 patients in this series. In addition, two of the five patients without Hill-Sach's lesions had bony changes pathognomonic for the Bankart lesion on the apical oblique projection. A total of 25 of the 28 patients had objective roentgenographic evidence of previous anterior subluxation. Eleven of the patients had arthroscopic examinations confirming various pathology consistent with anterior subluxation, including anterior or inferior labral tears, Hill-Sach's lesions, anterior inferior glenoid articular cartilaginous erosion, or Bankart lesions. Two of the twenty-eight patients had pathology in addition to evidence of previous occult subluxation which may have played a role in their symptoms, one having had osteolysis of the distal end of the clavicle and another having subacromical adhesions.

Open reduction of a lateral femoral notch associated with an acute anterior cruciate ligament tear.

The lateral notch is a radiographic sign that describes a depression in the lateral femoral condyle near the terminal sulcus. The sign was first described in association with chronic instability in an anterior cruciate ligament-deficient knee. Recently, the senior author, after a prospective study, reported that these lateral notches might occur acutely at the time of anterior cruciate ligament injury. We report such a case in which the lateral femoral condylar depression fracture resulted in symptoms of lateral compartment incongruity. Open reduction and internal fixation were required. Anterior cruciate ligament reconstruction was performed as a staged procedure 2 months after fracture reduction. The postoperative result has been excellent for over 5 years. This case is an example that lateral femoral notches may be acute and a source of symptoms. In some cases, reduction and fixation of significant depressions in association with ligament reconstruction can alleviate these symptoms and may improve the patient's long-term result.

Current concepts regarding the anterior cruciate ligament.

In an athlete, the torn anterior cruciate ligament (ACL) is best managed by surgical reconstruction. The failure to recognize an acutely torn ACL and the resulting inappropriate treatment can result in additional irreversible damage to the athlete's knee. Yet, as recently as 1983, a report documented that physicians failed to diagnose acutely torn ACLs in 93% of 103 patients who were subsequently seen with symptomatically unstable knees. Persistent instability is manifested by paroxysmal anterior shifts of the tibia on the femur during pivotal maneuvers, which may cause further irreparable damage. The injury has commonly gone unrecognized despite the fact that knowledge of the ACL's function, mechanism of its injury, and clinical presentation when torn can often lead to a strong suspicion of a torn ACL through history-taking alone. Documentation of hemarthrosis and a poor end point to passive tibial anterior displacement on the femur while the knee is between 10 degrees and 30 degrees of flexion confirms the diagnosis. Arthroscopically aided intra-articular reconstruction has emerged as the favored technique over extra-articular and combined intra-articular/extra-articular procedures. The bone-one-third patella tendon-bone autogenous graft remains the standard to which other graft materials are compared in reconstructing the ligament. Allograft reconstruction offers similar results with less postoperative morbidity and is reasonably safe; the spread of human immunodeficiency virus from donor to patient remains a remote possibility.

Delayed proximal repair and distal realignment after patellar dislocation.

Twenty athletes with distal malalignment who sustained unilateral traumatic patellar dislocation remained impaired by chronic instability. Surgery was performed at a mean age of 18 years. Posttraumatic attenuation of the medial patellofemoral ligament was repaired near the margin of the patella in 10 knees and avulsion or attenuation posterior to the vastus medialis obliquus in 10 knees. Advancement of the medial patellomeniscal ligament at the margin of the patella and normalization of the Q angle to 10 degrees by tibial tubercle osteotomy were performed in each knee. Distal lateral retinacular release without release of the normal vastus lateralis tendon was performed. Results were judged according to Turba et al, and activity levels were evaluated per guidelines of the International Knee Documentation Committee. Eighteen (90%) patients achieved good or excellent results and were unimpaired at a minimum of 24 months. Two patients achieved fair subjective results with some impairment in vigorous activity. There was no recurrent instability. Radiographically, the mean preoperative patellofemoral congruence angle improved from 20 degrees to 0 degree. Athletes who sustain an initial traumatic patellar dislocation after physeal closure and in whom conservative management fails can be treated successfully by repair of the medial patellofemoral ligament at the site of disruption and advancement of the medial patellomeniscal ligament combined with correction of an elevated Q angle.

Volar intercalated segment instability secondary to medial carpal ligamental laxity.

The midcarpal joint is stabilized by active, longitudinal compressive forces which produce balancing lateral volar flexion and medial dorsiflexion moments on the lunate. Laxity of the capitotriquetral ligament results in failure of the triquetral-hamate joint to produce a dorsiflexion moment, and the unbalanced volar flexion moment generated by the scaphoid produces volar intercalated segment instability (VISI). Four patients are reported to demonstrate the mechanics, clinical manifestations, and treatment of VISI.