Inferior femoral head cartilage and subchondral bone contribute critically to axial strength: A paired cadaveric biomechanical study

Although the biomechanics of the superior femoral head have been extensively investigated, far less is known about the structural role of the inferior infra-foveal region. This study investigates the impact of removing cartilage and subchondral bone from this region on the mechanical strength of the femoral head. In this study, five matched pairs of human cadaveric femoral heads were evaluated. A standardized resection of the inferior infra-foveal region was performed on one specimen from each pair, with the contralateral specimen left intact to serve as a control. All samples were embedded in a potting medium and subjected to axial compression to failure using a servo hydraulic testing apparatus. Load to failure was recorded as the primary outcome, and differences between paired specimens were analysed with a paired t-test. Inferior resection resulted in a reduction in load to failure across all specimen pairs, with decreases ranging from 8.45% to 33.33% and an average reduction of 21.88%. The paired t-test showed a mean difference of 328 lb (SD, 165.4 lb; SEM, 73.99), and the 95% confidence interval ranged from 122.6 to 533.4 lb. This effect was statistically significant (p = 0.011). The infra-foveal region provides essential mechanical support to the femoral head under axial loading. Excision of the infra-foveal cartilage and subchondral bone results in a notable decline in load-bearing capacity, reinforcing the need to maintain its integrity during hip-preserving procedures. Basic Science, Biomechanical Study.