Since August 1989 we have treated acute anteromedial instabilities with medial instability of 1+ and 2+ by augmented anterior cruciate ligament (ACL) reconstruction alone. Subsequently, functional therapy for the lesion of the medial collateral ligament (MCL) was carried out. In a follow-up examination, we evaluated Lysholm, Marshall, OAK and IKDC scores, measured stability with the KT 1000, and tested isokinetic muscle function in 28 patients. The majority demonstrated stable healing of the MCL and ACL and good or excellent knee functions and muscle strength.