Do pain referral patterns determine patient outcome after total hip arthroplasty?

Quality of life outcome and patient satisfaction after total hip arthroplasty are complex phenomena and many confounding determinants have been identified. Degenerative disease of the hip joint may present with variable patterns of pain referral in the lower limb. However the effect of varied preoperative pain referral patterns on patient outcome and satisfaction after total hip arthroplasty has not previously been examined. From 2000 to 2003, 236 eligible patients scheduled to undergo primary total hip arthroplasty were prospectively enrolled. The principal pain referral pattern (as hip, thigh or knee) was identified in all patients. Health related quality of life (HRQOL) was examined using the Harris Hip score (HHS), the Western Ontario McMaster Universities Osteoarthritis Index (WOMAC) and the 36-Item Short-Form Health Survey (SF-36) pre-operatively, 1 year and 2 years postoperatively and with the HHS at 3 months postoperatively. All patients were followed up for a minimum of 2 years. The frequency of the pain referral distributions were; hip pain 41%, knee pain 32% and thigh pain 27%. Patients in all groups were comparable preoperatively with respect to age, HHS, and both mean and domain specific WOMAC and SF-36 scores. The mean duration of symptoms was significantly greater in patients with knee pain when compared to the remaining two pain patterns. All patients demonstrated improvements in HHS, SF-36 and WOMAC scores after surgery. At all times postoperatively there were significant differences in mean HHS and mean and domain specific WOMAC and SF-36 scores between patients with hip or thigh pain and those with knee pain (p < 0.001). While notable, differences between hip and thigh pain were not as consistent however. Based on these findings, it appears that pre-operative pain referral patterns of hip arthritis are among the determinant factors for patient outcome and satisfaction after total hip arthroplasty, as measured using validated HRQOL scoring systems.