The relationship of the femoral origin of the anterior cruciate ligament and the distal femoral physeal plate in the skeletally immature knee. An anatomic study.

We defined the anatomic relationship of the anterior cruciate ligament femoral origin to the distal femoral physis in the skeletally immature knee with use of 12 fresh-frozen human fetal specimens (ages, 20 to 36 weeks). Each specimen underwent magnetic resonance imaging, was dissected free of soft tissue, sectioned in the sagittal plane, and stained. The spatial relationship of 1) the epiphyseal side of the physeal proliferative zone to the nearest point of bony attachment of the anterior cruciate ligament and 2) the origin of the anterior cruciate ligament to the over-the-top position were measured. The same measurements were made in 13 skeletally immature knees (ages, 5 to 15 years). We found that the femoral origin of the fetal anterior cruciate ligament developed as a confluence of ligament fibers with periosteum at 20 weeks, vascular invasion into the epiphysis at 24 weeks, and establishment of a secure epiphyseal attachment by 36 weeks. In the fetus, the distance from the anterior cruciate ligament femoral origin to the epiphysis was 2.66+/-0.18 mm (range, 2.34 to 2.94). There was no significant change in this distance in adolescent specimens (2.92+/-0.68 mm; range, 2.24 to 3.62). The over-the-top position was at the level of the distal femoral physis.

Acute elbow injuries in the National Football League.

We performed a retrospective review to evaluate acute medial collateral ligament injuries of the elbow in professional football players from 1991 to 1996 (5 seasons). There were 5 acute medial collateral ligament injuries in 4 players (1 player with bilateral involvement). All injuries occurred with the hand planted on the playing surface while a valgus or hyperextension force was applied to the elbow. There were 2 centers, both involved with long-snapping situations, 1 running back, and 1 quarterback. All elbows had valgus instability on physical examination. Despite this instability, all players were able to function without operative reconstruction of the medial collateral ligament. No evidence of valgus instability was seen at the time of follow-up (average, 3.4 years). Next, we reviewed all acute elbow injuries in the National Football League from the same 5-season period. Ninety-one acute elbow injuries were reviewed. Overall, there were 70 (76.9%) elbow sprains, 16 (17.6%) dislocation/subluxation patterns, 4 (4.4%) fractures, and 1 (1.1%) miscellaneous injury. Review of the acute elbow sprains revealed 39 (55.7%) hyperextension injuries, 14 (20%) medial collateral ligament injuries, 2 (2.9%) lateral collateral ligament sprains, and 15 (21.4%) nonspecific sprains. The epidemiology of the 14 medial collateral ligament injuries was studied in more detail. The 2 most common mechanisms of injury were blocking at the line of scrimmage (50%) and the application of a valgus force with the hand planted on the playing surface (29%). There were 8 linemen, 4 receivers, 1 running back, and 1 quarterback. All injuries were managed with nonoperative treatment. The average time lost was 0.64 games (range, 0 to 4). We report 19 acute medial collateral ligament injuries of the elbow in elite football players, 2 of whom are considered overhead throwing athletes, who were able to function at a competitive level without surgical repair or reconstruction, in contrast to baseball players, in whom the mechanics and demands may differ.

Potential pitfall of the EndoButton.

A clinical and cadaveric example show the EndoButton (Acufex Microsurgical Inc, Mansfield, MA), used for anterior cruciate ligament endoscopic fixation, flipping outside the extensor mechanism or vastus lateralis rather than flipping directly outside the lateral femoral cortex. This pitfall was caused by overdrilling the femoral socket beyond the recommended 6 mm and overadvancing the EndoButton beyond the required depth to flip the EndoButton. Overdrilling the femoral socket to a depth of 10 mm still allows the EndoButton to rest properly on the cortex without soft tissue interposition. Increasing angles of knee flexion at the time of Endobutton placement decrease the safe distance beyond the lateral femoral cortex for flipping without soft tissue interposition. There is also potential to flip the EndoButton within the substance of the vastus lateralis, but the flipping action is blunted and not discrete.

Osteonecrosis of the knee: current clinical concepts.

Osteonecrosis of the knee should be differentiated into two main categories: (1) primary, spontaneous, or idiopathic osteonecrosis and (2) secondary osteonecrosis (e.g., secondary to factors such as steroid therapy, systemic lupus erythematosus, alcoholism, Caisson decompression sickness, Gaucher's disease, hemoglobinopathies, etc.). Spontaneous or primary osteonecrosis of the knee presents with an acute knee pain in elderly patients. It is three times more common in women than in men. Traumatic and vascular theories have been proposed as a causative factor of osteonecrosis of the knee, but the precise etiology still remains speculative. High index of clinical awareness and a good history and physical examination are essential to make an early, accurate diagnosis. Plain radiographs are often normal during the early course of the disease and, in such instances, radioisotope bone scan and magnetic resonance imaging may be helpful. In the early stage of the disease, nonoperative treatment is indicated and many patients, if diagnosed early, have a benign course with a satisfactory pain relief and a good knee function. In patients with advanced stage of the disease, treatment options include arthroscopic debridement, curettage or drilling of the lesion, bone grafting, high tibial osteotomy, use of osteochondral allograft, and unicompartmental or total knee arthroplasty. The choice of treatment should be based on factors such as age of the patient, severity of symptoms, activity level and functional demands on the knee, site and stage of the lesion, and extent of deformity and secondary osteoarthritis. The clinical features and treatment of steroid-induced osteonecrosis of the knee are briefly discussed. In recent years, "postmeniscectomy" osteonecrosis has been reported, but at present its prevalence and pathophysiology remain unknown. It is possible that this may be a preexisting condition that was not recognized at the time of initial consultation or osteonecrosis may develop after meniscectomy in occasional cases.

The elbow.

Elbow disorders in the athletic population comprise a wide range of injuries from acute trauma to those caused by chronic overuse of the joint. Certain injuries are orthopedic emergencies that must be recognized immediately by the team physician to avoid potential complications. Other overuse injuries need to be accurately diagnosed and treated so further injury can be prevented and the athlete can return to competition as expediently as possible. Finally, the decision to refer an athlete for surgical treatment often rests with the team physician; only with an adequate understanding of the elbow disorders in the athlete can these decisions be made.