Dysplastic hip anatomy and joint reaction forces affect instantaneous and accumulative loads at the acetabular edge

Labral tears in developmental dysplasia of the hip (DDH) may be related to abnormal loads at the acetabular edge. Thus, quantifying in-vivo edge loads can help us clarify the reasons for labral tears. Using image-based musculoskeletal models (MSM), we developed new analyses to project hip joint reaction forces (HJRF) on DDH and healthy acetabula for estimation of edge loads in gait. Compared to healthy, HJRF in DDH were higher, and closer to the acetabular edge. As a result, higher edge loads were projected on the DDH acetabula, both instantaneously and accumulatively. The findings support risks of labral tears in DDH and may help inform clinical treatments.