Patient-reported outcomes for total hip and knee arthroplasty: commonly used instruments and attributes of a "good" measure.

Although the effectiveness of THA and TKA as interventions for end-stage degenerative joint disease has been well established, the use of instruments that measure outcome from the patient's perspective are relatively poorly investigated. Considering the increasing prevalence, associated risks, and high personal and financial cost associated with THA and TKA, patient-reported outcomes are required to ensure optimal selection of patients, and that postoperative outcomes outweigh the burden associated with surgical procedures. It is clear from the information presented that clinicians need to consider a number of factors when selecting a "good" patientreported outcome for use in their TJA patients. Not only does the instrument need to measure dimensions appropriate for THA and TKA patients, but it also needs to have minimal administrative burden, accessibility to a variety of clinicians and patients, reliability, validity, and responsiveness to change. Furthermore, knowledge regarding the minimal score that patients deem to be meaningful is useful in interpreting whether a patient has experienced real improvement in their condition after surgery. It is clear that further studies are required, particularly to fill some of the gaps regarding known psychometric properties of patient-reported outcomes for THA and TKA. Based on data acquired in THA and TKA patients for the instruments reviewed, it appears that OA-specific and TJA-specific measures for which patients have been involved in the developmental process (HOOS, KOOS, WOMAC, Oxford Hip and Knee Scores) can more consistently be considered "good" patient-reported outcomes for THA and TKA. Clinicians wishing to evaluate a broader range of dimensions may choose to complement these with one of the generic measures evaluated, bearing in mind the practical issues and psychometric limitations of these instruments when applied to THA and TKA patients.