Background: In 1967, Wilson described a clinical sign that he thought was diagnostic of medial femoral osteochondritis dissecans. He postulated that impingement of the tibial eminence on the osteochondritic lesion caused pain and a resultant compensatory lateral rotation during gait. He described reproducing the pain by internally rotating the patient's tibia during knee extension between 90 degrees and 30 degrees of flexion and then relieving that pain by externally rotating the tibia. He correlated healing of the lesion with conversion of the sign from positive to negative.
Purpose: To assess the validity of Wilson's assertions.
Study design: Retrospective clinical and radiographic case analysis.
Methods: Case records from 17 juvenile patients (ages 9 to 12) and 15 adolescent patients (ages 13 to 17) with medial femoral osteochondritis dissecans were reviewed for the presence or absence of Wilson's sign at initial and subsequent visits.
Results: Of the 32 patients, 24 (75%) with radiographically evident osteochondritis dissecans at the initial visit had negative signs. The remaining eight patients with positive signs had conversion of the sign to negative with lesion resolution.
Conclusions: In this series, Wilson's sign was of minimal clinical diagnostic value. When positive, the sign is useful as a clinical monitor during treatment.