SKELETAL KINEMATICS OF THE ANTERIOR CRUCIATE LIGAMENT DEFICIENT KNEE WITH AND WITHOUT FUNCTIONAL BRACES

Abstract

Steinmann traction pins were implanted into the femur and tibia of six subjects having a partial or complete anterior cruciate ligament (ACL) rupture. Patients jumped for maximal horizontal distance and landed onto their deficient limb with the knee braced and unbraced. Tibiofemoral rotations and translations showed a general trend across subjects, i.e. skeletally based curves were similar in shape and amplitude. The tibia displaced anteriorly from footstrike to about peak vertical force onset (Fy). Thereafter the tibia moved posteriorly during flexion. Intra-subject kinematics was very repeatable but differences in anterior tibial translations were small between the brace conditions. This may be due to the invasiveness of this protocol, that landings were onto a deficient limb, or subjects jumped within their own comfort limits which did not maximally stress the ACL. Inter-subject differences were typically much larger.