The pain and function of the hip (PFH) scale: a patient-based instrument for measuring outcome after total hip replacement.

The Pain and Function of the Hip (PFH) scale was developed following the recommendations of the Société International de Chirurgie Orthopedique et Traumatologie to assess the outcomes of total hip replacement (THR). This study evaluated metric properties of the PFH scale and its ability to measure clinical change (responsiveness) in consecutive patients undergoing THR. Patients were evaluated preoperatively and at 3 and at 12 months postoperatively. The PFH scale and the Nottingham Health Profile (NHP) were administered. Complete data were collected for 79 patients. Mean overall preoperative PFH score was 26.5 and mean overall PFH score 12 months postoperatively was 69.8 (P < .01). Correlation with the NHP was high (r = -0.64), and the magnitude of improvement (effect size) as assessed by the PFH scale was large (3.6 compared with 1.7 for the NHP). The PFH scale is simple and valid, and may complement routine clinical evaluation of hip replacement. Residual pain after hip replacement may have been previously underestimated.