Same but Different? Exploring the Role of Patient-Reported Outcome Measures and Clinician-Reported Outcome Measures in Postoperative Knee and Hip Arthroplasty Rehabilitation

<b>Background/Objectives</b>: Patient-reported outcome measures (PROMs) and clinician-reported outcome measures (CROMs) are used in orthopaedic rehabilitation to evaluate patients' health status and recovery. However, controversy still exists regarding their relevance and validity. This evaluation was conducted to assess the effectiveness and role of PROMs and CROMs in the orthopaedic rehabilitation outcome of patients who have undergone either total knee arthroplasty or hip arthroplasty. <b>Methods</b>: Outcome measures of 409 patients (68.3 ± 9.3 years; 34.2% male) with total knee arthroplasty and 308 patients (68.1 ± 10.6 years; 36.3% male) with total hip arthroplasty (control group) were assessed at baseline and after 21 days of inpatient rehabilitation. Effect sizes and correlations were analysed as they related to the use of PROMs and CROMs. To reduce statistical distortions caused by ceiling effects, we used a performance score (T2D) relying on two scores taken at the beginning and end of rehabilitation. <b>Results</b>: Large effect sizes (<i>d</i> > 0.97) for CROMs and medium effect sizes (<i>d</i> ≥ 0.65) for PROMs were observed in both groups. The standardised mean difference across all outcomes was 0.83 ± 0.59. PROMs worsened in 13.1% of all patients, while almost no patients showed a deterioration in CROMs. Correlations were highest between the Timed Up and Go and the Health Assessment Questionnaire scores (ρ > 0.45). <b>Conclusions</b>: Different and complementary assessment modalities of PROMs and CROMs serve as valuable clinical tools, providing a valid basis for interpreting patients' health outcomes.