Health status in patients awaiting hip replacement for osteoarthritis

Background. Hip osteoarthritis is a major cause of pain and disability, especially in the elderly. As part of a study investigating factors that could be associated with advanced osteoarthritis of the hip, we compared the health status of patients awaiting arthroplasty for hip osteoarthritis with controls. We further investigated the interaction of hip osteoarthritis with other variables (age, gender, social class and concurrent pain) in relation to health status. Methods. A case-control study was performed in two English health districts (Portsmouth and North Staffordshire) during 1993-1995. A total of 611 patients (210 men and 401 women) listed for hip replacement because of osteoarthritis over an 18-month period formed the case group and were compared with an equal number of controls selected from the general population and individually matched for age, gender and general practice. Cases and controls completed a structured interviewer-administered questionnaire, which included queries about their medical condition, occupation (from which a measure of social class was derived), and general health status using the SF36. Results. Physical function (t=32.1, P<0.001), social function (t=16.8, P<0.001) and perceived general health (t=4.1, P<0.001) were worse in the case group, but energy/vitality and mental health showed little difference between cases and controls. Cases were more likely to report knee pain than controls, but case-control status was not associated with pain in the fingers or shoulders, or with social class. However, differences in physical and social function between cases and controls did vary with socio-demographic factors and concurrent knee pain status. Conclusion. Patients awaiting hip-replacement because of osteoarthritis were more likely to be restricted in their physical and social life than adults in the general population, but mental state and vitality appear unimpaired in this group. This contrasts with findings from other chronic pain disorders. Manual social class is not linked to being on a waiting list for osteoarthritic hip replacement but does add to the burden on health status, particularly social functioning in those with osteoarthritis of the hip.