KINEMATIC IN-VITRO COMPARISON BETWEEN THE NORMAL KNEE AND 2 TECHNIQUES FOR RECONSTRUCTION OF THE ANTERIOR CRUCIATE LIGAMENT

The influence of anterior cruciate ligament sectioning and the results of its reconstruction on joint kinematics were studied using eight ca daver knees and a computerized system for analysis of three-dimensiona l motions. A Dacron(R) prosthesis was used in a transcondylar isometri c drill-guide-determined route, and in an over-the-top route. After se ctioning of the anterior cruciate ligament, the tibial motion increase d in several passive laxity tests including anterior/posterior transla tion as well as varus/valgus and internal/external rotation. Increased valgus rotation was also seen during a simulated active extension man oeuvre. The effect of anterior cruciate ligament reconstruction was se en only on anterior/posterior translation, where the drill-guide techn ique restored, and the over-the-top technique partially restored, norm al sagittal play at 90-degrees of knee flexion. At 30-degrees of knee flexion both methods reduced, but did not normalize, anterior/posterio r translation. An adverse effect of both techniques, more prominent wi th the drill-guide technique which involved an extensive notchplasty, was abnormal external tibial rotation in 90-degrees of knee flexion wi th the tibia in a gravity-determined position. Both techniques resulte d in less than normal external rotation in the screw-home mechanism.