The non operative treatment of isolated complete tears of the medial collateral ligament of the knee. A prospective study.

In a prospective randomized study, 20 patients with isolated grade-III injuries to the medial collateral ligament (MCL) of the knee were treated by two different conservative methods: immediate mobilization (group A) or plaster immobilization (group B). All patients were examined while under anesthesia. Valgus-stress radiographs were performed to document a 2+ opening (6-10 mm) on the medial side. Associated damage to other structures (cruciate ligaments, menisci, cartilage) was ruled out arthroscopically. Average follow-up was 1.5 years. All patients rated good or excellent, although a minimal laxity of 3 mm on valgus-stress radiographs was present in 60% of the cases. No significant differences between the two treatment modalities were identified, except that group-A patients returned to work sooner. These results confirm that isolated grade-III MCL tears can be treated successfully by immediate mobilization.