Hip Joint Contact Pressure Distribution During Pavlik Harness Treatment of an Infant Hip: A Patient-Specific Finite Element Model

In this study, CCP in a cartilaginous infant hip was investigated through patient-specific finite element (FE) modeling. We simulated CCP of the hip equilibrated at 90  deg flexion at abduction angles of 40 deg, 60 deg, and 80 deg. We found that CCP was predominantly distributed on the anterior and posterior acetabulum, leaving the superior acetabulum (mainly superolateral) unloaded. From a mechanobiological perspective, hypothesizing that excessive pressu re inhibits growth, our results qualitatively predicted increased obliquity and deepening of the acetabulum under such CCP distribution. This is the desired and observed therapeutic effect in successful PH treatment. The results also demonstrated increase in CCP as abduction increased. In particular , the simulation predicted large magnitude and concentrated CCP on the posterior wall of the acetabulum and the adjacent lateral femoral head at extreme abduction (80 deg). This CCP on lateral femoral head may reduce blood flow in femoral head vessels and contribute to AVN. Hence, this study provide s insight into biomechanical factors potentially responsible for PH treatment success and complications.
Source: Journal of Biomechanical Engineering - Category: Biomedical Engineering Source Type: research