Distal femoral morphology as a risk factor for osteoarthritis.

Osteoarthritis (OA) is a leading cause of disability affecting millions of adults in the United States, commonly resulting in the need for total knee arthroplasty (TKA) to restore mobility and quality of life. This study investigates potential differences in baseline distal femoral shape between individuals who received TKA due to OA and a control group representing a healthy population. Using three-dimensional geometric morphometrics, distal femoral shape was examined in 43 adult skeletons from the University of Tennessee Donated Skeletal Collection. Results suggest that natural femoral shape in TKA-receiving individuals may differ from that of the control group, with some individuals in the TKA sample occupying more extreme regions of the femoral shape space. In particular, the landmarks of the medial condyle appear anteriorly shifted in the TKA sample, identifying this region as a candidate location for future exploration into group differences. While future longitudinal studies are required to determine direct causal links between morphology and OA as a health outcome, existing clinical literature has identified that even minor mismatch in conarticular shape can alter the biomechanical environment of the joint. These results are a first step in identifying outliers for femoral morphology and potential regions of femoral anatomy that may predispose individuals to OA, highlighting the importance of evaluating morphological variations as potential risk factors. This study further contributes to our understanding of the boundaries of articular morphospace and its implications for arthropathy, underscoring the need for further research to establish direct links between baseline articular shape and OA onset.