The influence of total hip replacement on hip pain and the use of analgesics.

The influence of total hip replacement (THR) on pain and use of analgesics was evaluated in 511 patients with McKee-Farrar and Brunswik prostheses. The mean age of the patients was 63.8 years and the mean follow-up time 4.2 years. The average grade of pain decreased from 1.8 to 4.9 as evaluated according to Charnley. The proportion of regular users of all analgesics decreased from 75% to 17% (P less than 0.001). Indomethacin was the most common preoperative drug and the proportion of its regular use decreased from 47 to 12% (P less than 0.001). The preoperative association which existed between the grade of pain and the regular drug users in each pain grade decreased more than expected by the preoperative figures. Postoperatively those with previous hip operations, McKee-Farrar prosthesis, one hip replaced, reapplications and removal of the prosthesis gave inferior results with respect to pain than those without previous surgery, with Brunswik prosthesis, both hips replaced and with the original prosthesis in situ. In addition to previous THR operations, type of the hip prosthesis, bilateral or unilateral surgery, primary or secondary coxarthrosis and reapplication of the prosthesis influenced the use of drugs. THR, however, brought a marked drop in the use of analgesics and this effect should be taken into account when assessing the costs and benefits of THR.