Reporting Completeness of Usual Care Comparator Groups in Exercise‐Based Trials for Knee Osteoarthritis: A Meta‐Research Systematic Review

BACKGROUND: Exercise-based randomized controlled trials are essential for guiding the management of knee osteoarthritis, but their interpretability depends on transparent reporting of both intervention and comparator groups. The term usual care (UC) is frequently used as a comparator, yet its reporting quality remains unclear. OBJECTIVE: To evaluate the reporting completeness of UC comparator groups in randomized controlled trials (RCTs) of exercise-based interventions for knee osteoarthritis. METHODS: This systematic review included RCTs of exercise-based interventions for adults with knee osteoarthritis that used UC as a comparator. Searches were conducted in MEDLINE, EMBASE, CENTRAL, PEDro, CINAHL, and SPORTDiscus up to December 2024. Reporting completeness was assessed using the Template for Intervention Description and Replication (TIDieR) checklist and analysed using continuous and dichotomised approaches. RESULTS: Sixty-seven RCTs were included. Reporting completeness of UC interventions was consistently low. Median TIDieR scores (range 0-12) were higher for exercise interventions (4.0; IQR 3-5) than for UC comparators (1.0; IQR 1-2). Continuous analyses detected significant differences between groups, whereas dichotomised analyses did not. Only 22.3% of exercise-based interventions achieved high reporting completeness. No improvement was observed after publication of the TIDieR checklist, and no meaningful association was found between methodological quality and reporting completeness. CONCLUSIONS: Reporting of UC comparator groups in exercise-based RCTs for knee osteoarthritis is poor and has not improved over time. Although exercise interventions are better reported, overall completeness remains low, highlighting the need for improved reporting practices to support clearer interpretation of clinical trial evidence.