Total knee arthroplasty and total hip arthroplasty are 2 of the most commonly performed elective orthopaedic procedures. They are remarkably successful in relieving pain and improving function in individuals with advanced, symptomatic arthritis. Since, in addition to providing benefits, these procedures pose risks, it is important to provide clinicians with guidance in determining which patients should undergo total joint replacement surgery. The development of the RAND approach in 1986 and its application to total hip and knee replacement have enabled clinicians, payers, and others to assess the appropriateness of past and current procedures for particular patients. However, current appropriateness criteria for elective orthopaedic procedures have important limitations that suggest that they be used cautiously. New approaches to the assessment of appropriateness that overcome many of these limitations are under development.