Determinants of willingness to pay for hip and knee joint replacement surgery for osteoarthritis

Objectives. To determine whether patients with osteoarthritis (OA) would be willing to pay for joint replacement and whether patient characteristics o r health outcomes, including pain, physical function and health-related qua lity of life, were related to willingness to gay (WTP). Methods. Patients who had undergone primary total hip replacement (THR) or total knee replacement (TKR) for OA completed a disease-specific questionna ire (Western Ontario and McMaster: WOMAC index), a generic measure of healt h status (Medical Outcome Study Short Form-36: SF-36) and an Evaluation Que stionnaire to measure WTP and satisfaction with the replacement. Results. Responses were obtained from 109 (77%) THR patients and 129 (72%) TKR patients. Mean age of respondents was 67 yr for THR (47% female) and 73 yr for TKR (60% female). Overall, 85% of patients responded to the WTP que stion. Of the THR patients, 71% were willing to pay something, 11% were not willing to pay anything and 18% did not answer the question. For TKR patie nts these figures were 70, 16 and 14% respectively. However, of those who r esponded to the WTP question, only 25% of the TKR patients and 18% of the T KR patients indicated they would be willing to pay the actual current avera ge cost of the operation in Australia (greater than or equal to A$15 000). A lower postoperative pain score (as measured by the WOMAC index) was a sig nificant predictor of WTP for both THR and TKR patients. Income also signif icantly predicted WTP in THR patients but not in TKR patients. The other si gnificant predictors for TKR patients were older age, having private health insurance and willingness to recommend joint replacement to others. Conclusions. Willingness to pay was a measure that was understandable and a cceptable to patients, most of whom were willing to pay something. There wa s a high correlation between WTP, good health outcomes and patient satisfac tion, pain relief being the dominant determinant.