During the period 1967 to 1971, 64 cadets at the United States Military Academy, West Point, New York, had surgical repair for isolated tear of the anterior cruciate ligament. In a 5-year follow-up study to determine the functional impairment, present disability, and reinjury to the knee, 32 of the 64 patients were located and evaluated by radiographic examination and either by interview or by questionnaire. Twenty-two were commissioned to full duty. 23 had attended ranger or airborne school, and 16 had been in combat. Impairment of ordinary activities was noted by 12 and impairment of athletic endeavors by 24; pain by 71%; swelling by 66%; stiffness by 71%; and instability by 94%. Seventeen of the 32 had had a significant reinjury after the repair of the anterior cruciate ligament. Clinically, we can diagnose the isolated tear of the anterior cruciate ligament by four essential ingredients--a pop at time of injury, inability to continue participation, gross swelling of knee, and maximal swelling within 12 hr. The mechanism of injury is usually deceleration and change of direction, not contact with another player. The follow-up study on this small series indicates that the patients have progressive deterioration of the knee.

Multiplanar spin-echo magnetic resonance imaging was performed on 54 patients with acute complete anterior cruciate ligament tears. Imaging was done within 45 days of index anterior cruciate ligament injury. Spin-echo T1- and T2-weighted images were used to determine the lesion morphology and location. Only the T2-weighted sagittal images were used for the incidence assessment; T2-weighted spin-echo imaging reflects free water shifts and best indicates the acute edema and inflammatory changes from injury. Eighty-three percent (45 of 54) of the knees had an osseous contusion directly over the lateral femoral condyle terminal sulcus. The lesion was highly variable in size and imaging intensity; however, the most intense signal was always contiguous with the subchondral plate. Posterolateral joint injury was seen in 96% (43 of 45) of the knees that had a terminal sulcus osseous lesion determined by magnetic resonance imaging. This posterolateral lesion involves a spectrum of injury, including both soft tissue (popliteus-arcuate capsuloligamentous complex) and hard tissue (posterolateral tibial plateau) injuries. The consistent location of the osseous and soft tissue injuries underscores a necessary similar mechanism of injury associated with these acute anterior cruciate ligament tears. Based on these characteristic findings, several proposed mechanisms of injury are discussed.

This study demonstrated that it was possible to establish a concise classification system to group patients with meniscal root tears by tear morphology. Treatments received varied across tear types.

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