Nonoperative treatment of grade II and III sprains of the lateral ligament compartment of the knee.

The purpose of the study was to learn the long-term results of nonoperatively treated sprains of the lateral compartment of the knee joint, generally known to be relatively rare injuries. A multidimensional follow-up analysis was performed on an average 8 years after the injury in 11 patients with Grade II sprains and in 12 patients with Grade III sprains, including four standardized knee scoring scales for subjective, objective, functional, and radiographic evaluation, as well as isokinetic and isometric strength evaluations. The result in Grade II sprains of the lateral ligament compartment (LAT) was generally good, although residual lateral laxity was common. In Grade III sprains, the results were much worse, with a high frequency of persisting severe or gross lateral laxity, insufficiency of the ACL, muscle weakness, and posttraumatic osteoarthritis of the injured knee. Grade II sprains of the LAT respond successfully to nonoperative treatment; in Grade III sprains, however, such treatment cannot be recommended as a method of choice.