Health-related quality of life and the assessment of outcomes of total hip replacement surgery

Health-related quality of life is the primary objective of total hip replacement surgery, but optimal methods of assessing this construct have not been agreed. A sample of 186 patients receiving total hip replacement surgery were invited to complete a number of assessments pre-surgically and again at a six month follow-up clinic. On both occasions, they completed the Oxford Hip Score, the SF-36 and, in addition at the follow-up clinic, a small number of retrospective judgements about their health and the success of surgery. The purpose of the study was to investigate two issues: (i) the responsiveness of a condition-specific (Oxford Hip Score) compared to a generic instrument (SF-36) and (ii) the validity of retrospective judgements compared to evidence of outcomes obtained from prospective monitoring of health status. The condition-specific measure was found to be more responsive to changes of importance to the patient. Retrospective judgements were found to have construct validity as evidence of outcomes of importance to the patient but also to be somewhat influenced by respondents' current health status rather than the extent of change experienced from before surgery. A transition question was less prone to this influence.