Evaluating the Content Validity of Four Performance Outcome Measures in Patients with Elective Hip Replacements and Hip Fractures

Objectives: To assess the content validity of performance outcome (PerfO) measures for use with patients undergoing hip fracture (HF) surgery and elective total hip replacement (eTHR). Methods: This study was a substudy of a broader evaluation of measurement properties of PerfO measures. The PerfO measures assessed were timed up and go (TUG), four-step stair climb (4SC), long stair climb (LSC), and repeated chair stand (RCS). For this substudy, HF and eTHR participants were interviewed to evaluate the relevance and difficulty of each PerfO measure. Qualitative analysis was conducted on interview transcripts, and summaries of coded data were produced to assess saturation. Results: All 18 HF participants related the PerfO measures (TUG, 4SC, and RSC) to activities they completed in daily life, with slight variations in some specific aspects. For the eight eTHR participants, the correspondence between the PerfO measures (TUG, 4SC, and LSC) and activities in daily life varied: all participants saw similarity in the movements for the TUG; most undertook short stair climbs in daily life, but most did not regularly undertake LSC in daily life. Nevertheless, all HF and eTHR participants reported that the PerfO measures were relevant and had a level of difficulty similar to daily activities. Conclusions: This study contributes novel methods that adapt US regulatory guidance for patient-reported outcome measures to the evaluation of PerfO measures. A structured approach was used to explore specific details of each measure and correspondence to everyday life. This study demonstrates how content validity of PerfO measures can be meaningfully assessed.