Long-term prognosis of isolated partial medial collateral ligament ruptures. A ten-year clinical and radiographic evaluation of a prospectively observed group of patients.

We prospectively observed 38 patients with nonoperatively treated isolated partial ruptures of the knee medial collateral ligament at 3 months, 4 years, and 10 years after the initial trauma using clinical and radiographic examinations. The initial diagnoses were based on clinical and arthroscopic examinations. Three months after injury, 28 patients (74%) had regained nearly normal knee function and muscle strength, and 75% of these patients could perform at their preinjury activity level (competitive team sports). Five patients (13%) had increased valgus laxity (grade 1) in the injured knee. After 4 years, the patients had a median Lysholm score of 100 (range, 64 to 100). Thirty-three patients (87%) had normal knee function during strenuous activities. Repeat injuries to the medial collateral ligament occurred in two patients (5%), and another two patients sustained cruciate ligament injuries during the follow-up period. After 10 years, the Lysholm score (median, 95; range, 73 to 100) was lower compared with the 4-year score (P < 0.03), but the patients still performed on a similarly high activity level. Five patients (13%) had distinct signs of beginning osteoarthritis (Fairbank's signs) on radiographs, but none had joint space reduction.