Concomitant therapy: an outcome variable for musculoskeletal disorders? Part 2: total joint replacement in osteoarthritis trials.

Interest has grown in using the requirement of total joint replacement (TJR) as a "hard" outcome measure. Limitations exist, however, in the use of such an outcome, in particular the variability in the decision to perform surgery, length of surgical waiting lists, and sensitivity to change. This special interest group is exploring ways of retaining the clinical relevance of TJR but overcoming the problems--2 alternative outcomes are being considered: "time to physician's decision to recommend surgery" and "time to fulfilling criteria for total joint replacement."