One-legged stance as a representative static body position for calculation of hip contact stress distribution in clinical studies

It was shown in several clinical studies that static one-legged stance may be a relevant body position to describe the loads acting at the hip. However, the stress distribution averaged during movement may better describe hip load than hip contact stress distribution in the static body position. Using data on the resultant hip force during walking taken from the measurements of Bergmann (2001), spatial distribution of contact stress over the articular surface was calculated by the HIPSTRESS method and compared with the stress distribution in one-legged stance. It is shown, that the shape of the contact stress distribution during one-legged stance closely resembled the averaged contact stress distribution during the walking cycle (Pearson's correlation coefficient R2 equals; .986; p < .001). This finding presents a link between the hypothesis that the averaged contact stress distribution during a walking cycle is crucial for cartilage development and the results of clinical studies in which the calculated distribution of contact stress in one-legged stance was successfully used to predict the clinical status of the hip.