Dynamic knee stability after anterior cruciate ligament rupture.

A functional classification scheme has been devised to study knee stabilization strategies after anterior cruciate ligament rupture. A screening examination can determine which patients may be candidates for nonsurgical treatment (potential copers). A rehabilitation program that includes support surface perturbations can improve the potential coper's ability to stabilize the knee. Biomechanical, electromyographic, and clinical data support the classification scheme and perturbation training for improving dynamic knee stability.