High variability in the assessment of physical function following total hip arthroplasty: a systematic review

Total hip arthroplasty (THA) is a highly successful surgical intervention, yet the assessment of postoperative physical function lacks standardization. This systematic review investigates the variability in outcome measures used to evaluate physical function following THA over the past 12 years.

Following PRISMA guidelines, we analyzed 406 randomized controlled trials (RCTs) from PubMed, Ovid, ScienceDirect, and Epistemonikos, focusing on studies published between 2013 and February 2025. Outcome measures were categorized into patient-reported (PROMs), performance-based (PBOMs), and impairment-based (IBOMs) measurement tools. Data extraction included study design, measurement types, and temporal trends.

Significant heterogeneity was observed, with PROMs employed in 95% of studies (e.g., Harris Hip Score, WOMAC), while PBOMs (18%) and IBOMs (22%) were underutilized. Only 8% of studies combined all three measurement types. PROMs dominated surgical studies (97%), whereas PBOMs and IBOMs were more prevalent in rehabilitation research. Temporal analysis revealed stable PROM usage but declining PBOM and inconsistent IBOM adoption.

The lack of standardized functional assessment complicates cross-study comparisons and meta-analyses. While PROMs provide valuable patient perspectives, their limitations necessitate complementary objective measures. We advocate for the adoption of core outcome sets, such as those proposed by OMERACT, to improve consistency in THA outcome evaluation. Future research should integrate PROMs, PBOMs, and IBOMs for a comprehensive assessment of postoperative function.