Predicting the effects of a distal femoral cartilage defect using an accurate three-dimensional dynamic finite element model

Objectives: The present study aimed to investigate how variables associated with an osteochondral femur defect affect tibiofemoral contact using three-dimensional (3D) finite element analysis. Methods: We reconstructed a 3D finite element model of a human knee joint, including the bone structure, cartilage, meniscus and tendons. Then, we built an 8-mm-diameter defect on the weight-bearing area of femoral condyle cartilage in finite element mode. At various flexion angles ranging from 0 degrees to 90 degrees, a 350-N vertical tibial plateau load and a 400-N traction force in the quadriceps direction were applied to the unconstrained proximal femur. After constructing the 3D model, Abaqus software was used for finite element analyses and calculations to examine the effect of an 8-mm defect in the medial femoral condyle (high-weight-bearing region) on the stress of the cartilage and meniscus at 0 degrees, 30 degrees, 60 degrees, and 90 degrees of knee flexion. Results: The results indicated that the forces in the tibiofemoral knee joint increased obviously at 0 degrees, 30 degrees, and 60 degrees of knee flexion during compressive loading. However, at a flexion angle of 90 degrees, the difference in peak stress was not statistically significant. Conclusion: This study demonstrated a significant increase in compressive stresses in the femoral cartilage, meniscus, and tibial cartilage with an 8-mm defect in the medial femoral condyle at 0 degrees, 30 degrees, 60 degrees, and 90 degrees of knee flexion. The present findings provide a better understanding of degenerative arthritis.