Clinical results 2 years after total hip replacement (WOMAC/SF-36) and comparison with the normal population (SF-36)

Aim: The aim of this study was to determine the outcome after total hip replacement (THR) with the WOMAC and the SF-36 as well as to identify the most responsive items and to elucidate the reasons for increased pain postoperatively. Methods: 73 patients filled out the questionnaires preoperatively and 3, 6, 12, 24 months postoperatively. All mean subscales and the responsiveness for each question were calculated. The patients with increased pain postoperatively were reassessed. Results: All WOMAC subscales and six of the eight SF-36 subscales showed significant improvements after THR (p < 0.05). The most responsive items were the pain and disability questions (SRM, ES > 1.5). Two patients with a higher pain score postoperatively had associated symptomatic degenerative lumbar spinal disease. Conclusions: The WOMAC and the SF-36 are valid measures of the outcomes of THR in their German translations and document the good results after THR. Two years after THR the patients reach the same health state compared to an age matched control group in the population. The WOMAC contains more questions of higher responsiveness than the SF-36. A higher pain score postoperatively may be caused by degenerative disease of the lumbar spine.