Early mobilization of rabbit medial collateral ligament repairs: biomechanic and histologic study.

The postoperative management of repaired medial collateral ligaments is controversial. There are proponents for either early mobilization or immobilization. To contribute to an understanding of the issues, 24 adult Dutch rabbits were divided into four groups and a comparative study was made of their incised medial collateral ligaments, contrasting early immobilization with mobilization at three and six weeks. The ligaments were studied histologically and biomechanically. At three weeks, the immobilized ligaments were twice as strong as mobilized ligaments. Histologically, the immobilized ligaments demonstrated more fibroblastic reaction while the mobilized ligaments showed more mature tissue development at the repair site. There were no statistically significant differences between knees mobilized for six weeks and knees immobilized for three weeks and then subsequently mobilized for three weeks. In view of these results, the authors conclude that the deleterious effects of immobilization should be considered when planning postoperative or postinjury treatment of torn medial collateral ligaments.