Relationship between Knee Flexion at Heel-Strike of Walking and the Location of Thickest Femoral Cartilage in ACL Reconstructed and Contralateral Knees

+Scanlan, S F; Favre, J; Andriacchi, T P + Stanford University, Stanford, CA, 2 VA Palo Alto Health Care System, Palo Alto, CA [email protected] INTRODUCTION: It has been suggested that the spatial variations in the morphology and mechanical properties of articular cartilage are conditioned to the cyclic loading during ambulation [1]. Specifically it has been shown that regional variation in healthy femoral cartilage thickness distribution is associated with knee flexion during walking, where the thickest femoral cartilage was more posterior in knees that were more flexed at heel-strike [4]. Given the role of the anterior cruciate ligament (ACL) in guiding flexion-extension of the knee during walking, it is possible that individual variations in the patterns of knee flexion at high load phases (e.g. heel-strike) of the gait cycle would influence the normal distribution of cartilage thickness [1]. Assessing knee flexion in the context of a potential pathway to cartilage degeneration is important since it has been reported that 25% of patients have at least 5o of knee extension loss after ACL reconstruction [5]. Thus, the goal of this study was to test the hypothesis that the anterior-posterior (A-P) location of the thickest cartilage in the medial and lateral condyles of the femur will be correlated with knee flexion at heel-strike of walking for both ACL reconstructed and healthy contralateral knees. It is hypothesized that the thickest femoral cartilage will be more posterior in knees that are more flexed at heel-strike.