DECREASE IN VALGUS STIFFNESS AFTER MEDIAL KNEE LIGAMENT INJURY - A 4-YEAR CLINICAL AND MECHANICAL FOLLOW-UP-STUDY IN 38 PATIENTS

The clinical outcome after partial rupture of the medial collateral kn ee ligament is reported to be good, but there is a lack of objective a ssessment of persistent valgus laxity. We prospectively followed 38 co nsecutive patients with an isolated partial medial ligament rupture. A fter diagnostic arthroscopy, all patients were treated by early functi onal rehabilitation. At 4 years, besides clinical routine laxity tests , varus/valgus rotation, internal/external tibial rotation, initial an d endpoint valgus stiffnesses, initial and endpoint internal/external rotational stiffnesses were measured by instrumented computerized pass ive motion analysis (Genucom). Most patients had normal knee function and muscle strength as early as 3 months after injury and returned to their pre-injury activity level without problems. At 4 years, 2 knees had minor residual valgus laxity at the manual examination, all other knees appeared stable. The instrumented tests also showed equal varus/ valgus rotations and internal/external rotational stiffnesses in injur ed and healthy knees, but a decrease in the initial valgus stiffness a nd a decrease in the internal/external tibial rotation of the injured knee.