Abstract
BACKGROUND: The knee's passive movement is insufficient to determine function in patients following ACL reconstruction. HYPOTHESIS: We hypothesize that there are kinematic differences in the lower extremities (LE) during stair climbing and ground level walking following ACL surgery between the intact and reconstructed sides. STUDY DESIGN: This was a retrospective cohort study. Eleven patients with an average age of 15.3 years at the time of their ACL reconstructive surgery (BPTB autograft) participated in the study. METHODS: Patients were followed for at least 2 years post surgery. The subjects underwent a non-weight bearing ability test to reproduce predetermined knee joint positions. Their LE's velocity and joint kinematics were then measured during level ground walking and on a set of custom designed stairs as they ascended and descended. RESULTS: During level ground walking the maximum internal rotation at the ankle during the swing phase on the reconstructed side increased significantly from 2.3º to 19.9 º compared to the unreconstructed limb (P=0.04). The leading reconstructed knee during stair ascent exhibited less knee flexion as compared to the unreconstructed knee for each step (1(st) step: 74.2º vs 81.5º; 2(nd) step:93.6º vs 97.6º; 3(rd) step: 48º vs 53.5º; 4(th) step: 72.5º vs 78.1º; p<0.05). CONCLUSIONS: A two-year follow-up study in adolescents who had a bone-patellar tendon-bone autograft demonstrated that they had normal knee proprioception and 3D joint rotations of the LE, while showing an alteration of the ankle and knee kinematics during walking or ascending stairs.