Clinical Biomechanics of the Hip Joint

Abstract

The ball and socket structure of the hip joint contributes both to the joint’s underlying stability and functional mobility. During functional tasks such as walking the hip joint structures are subject to tremendous forces, on the order or three times an individual’s body weight. Therefore, a thorough understanding of hip joint biomechanics is important for the diagnosis and treatment of hip joint pathology. Hip joint pathology can alter biomechanics at the hip joint itself, as well as at body regions above and below the hip joint. In the clinical setting, different functional tasks such as walking, step ups or step downs, and double- or single-leg squatting are used to evaluate movement quality or identify movement compensation, which may contribute to an individual’s hip pathology. In the laboratory setting, human motion analysis has been commonly used to quantify joint biomechanics. Recent interest in clinical hip conditions such as femoroacetabular impingement (FAI) syndrome, acetabular dysplasia, and hip instability have led to the emergence of biomechanics literature in people with these hip conditions. The aims of this chapter are to 1) review normal hip joint kinematics and muscle function, 2) discuss hip joint pathomorphology and pathomechanics, and 3) to review biomechanical evidence in hip disorders such as FAI syndrome and acetabular dysplasia and hip instability.