Evaluation of the Measurement Properties of Four Performance Outcome Measures in Patients with Elective Hip Replacements, Elective Knee Replacements, or Hip Fractures.

OBJECTIVES

To evaluate the measurement properties of four performance outcome (PerfO) measures (timed up and go, four-step stair climb, long stair climb, and repeated chair stand) in three patient populations(elective total hip replacement [eTHR], elective total knee replacement [eTKR], and hip fracture [HF]).

METHODS

A cross-sectional and longitudinal design was used to assess the PerfO measurement properties using the US Food and Drug Administration guidance for industry around patient-reported outcome measures to support labeling claims. Patient-reported outcome measures and patient- and clinician-reported global concept items were completed along with four PerfO measures at visit 1 and two follow-up visits. Measurement properties assessed included reliability, construct validity, ability to detect change, and estimates of meaningful change.

RESULTS

A total of 280 patients (100 eTHR, 105 eTKR, and 75 HF) were recruited, with most (n = 276) providing data at visit 1. Most of the patients were female (64%) and retired (64%), and had at least one comorbidity (91%). Inter-rater and test-retest reliability ranged from good to excellent (0.73 ≤ intraclass correlation coefficient ≤ 0.95) for each PerfO measure. Known-groups validity was demonstrated for all PerfO measures, with those reporting less pain better physical functioning and those who did not use an assistive device having quicker mean completion times. Construct validity and ability to detect change were demonstrated and estimates of meaningful change derived.

CONCLUSIONS

This study found the measurement properties of four PerfO measures in samples of patients with eTHR, eTKR, and HF to be supported for consideration of future use, and provided estimates for interpretation of change.