Kinematics after tear in the anterior cruciate ligament - Dynamic bilateral radiostereometric studies in 11 patients

We studied the kinematics of both knees using radiostereometry in 11 patien ts with unilateral injury of the anterior cruciate ligament and normal cont ralateral knee. Continuous radiostereometric exposures at a speed of 2-4 ex posures a second were performed, when the patients ascended an 8 cm high pl atform. The tibial center was more dorsally displaced and the tibia more externally rotated on the injured side. This increasing external tibial rotation was associated with increased anterior displacement of the lateral femoral cond yle. The latter also displayed less anterior-posterior translations during continuous extension. The anterior-posterior translation of the medial cond yle was about the same as on the uninjured side. Changes in the kinematics of the knee joint due to rupture of the anterior cruciate ligament can result in an abnormal joint load, which may increase the risk of damage to the cartilage and the menisci.