Normal and osteoarthritic hip joint mechanical behaviour: a comparison study.

The assessment of contact areas within the hip joint during activities of daily living is of critical importance to understand why degeneration mechanisms are sometimes initiated. A generic finite element model is developed and constrained with experimental personalized conditions to locate contact areas and determine pressure distribution, both during walking and stair climbing. Bony structures are positioned in relation to each other by using experimental kinematical data. Implemented loading conditions are computed from an inverse dynamic approach coupled with an optimization method. The mechanical behaviour of a healthy hip joint is first simulated. This model is then used as a reference for the evaluation of a pathological mechanical behaviour. Thus, experimental data are collected for a patient presenting a coxarthrosis. The comparison of the pathological and normal behaviours emphasizes that the contact area swept within the osteoarthritic hip joint is limited both during walking and stair climbing.