The Effect of Locomotion on the Outcome following Total Hip Arthroplasty

The relationship between contralateral hip arthritis and co-morbid medical conditions that affect a patient’s ability to walk, and outcome following total hip arthroplasty (THA) is not fully understood. We investigated this relationship in a prospective, multi-centre study. 1497 hips (1428 patients) were recruited. At five years follow-up there was complete data for 1053 hips. We recorded Oxford Hip Score (OHS) and Charnley Class (CC) both pre-operatively and at one and five years after surgery. Pre-Operatively there was a significant difference in OHS between CC categories and OHS deteriorated from CC-A to CC-C (p<0.001). The absolute OHS was significantly worse in CC-C compared to CC-A. Patients who remained in CC-A at five year follow-up had a larger change in OHS (mean 24) compared to those who had changed from CC-A to CC-C at five years (mean 21) p<0.001.

The OHS an outcome measure frequently used for THA is influenced by several extraneous factors which may be present pre-operatively but also change over time. These factors include the condition of the opposite hip as well as other disease processes that affect a patient’s locomotion and therefore interpretation of OHS in isolation without additional information may not be appropriate.