Researchers have summarized clinically meaningful thresholds for commonly used patient-reported outcome measures following arthroscopic surgery for femoroacetabular impingement, providing reference values that may help physicians interpret postoperative improvement and treatment success.
The systematic review followed the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. Researchers searched PubMed, Web of Science, and Embase in October 2025 for clinical studies reporting the minimal clinically important difference, patient-acceptable symptom state, substantial clinical benefit, or minimally important change for patient-reported outcome measures used following arthroscopic surgery for femoroacetabular impingement. Twenty-one studies involving 5,687 patients met the inclusion criteria. The review included prospective and retrospective level II and III studies, and the overall risk of bias was judged to be low to moderate.
The investigators evaluated clinically meaningful thresholds for the Hip Outcome Score, modified Harris Hip Score, International Hip Outcome Tool, Hip Injury and Osteoarthritis Outcome Score, Copenhagen Hip and Groin Outcome Score, Nonarthritic Hip Score, Western Ontario and McMaster Universities Osteoarthritis Index, Short Form-36, University of California, Los Angeles score, and visual analog scale. The review summarized published values for the minimal clinically important difference (MCID), patient-acceptable symptom state (PASS), substantial clinical benefit (SCB), and minimally important change (MIC) rather than generating new pooled estimates.
Among the most commonly reported measures, the modified Harris Hip Score had an average MCID of 14.6, PASS of 70.7, SCB of 94.0, and MIC of 8.0. For the Hip Outcome Score activities of daily living subscale, the corresponding values were 14.8, 75.2, 96.6, and 5.0, respectively. The International Hip Outcome Tool-33 had an average MCID of 25.1, PASS of 66.2, SCB of 85.9, and MIC of 10.0. Additional threshold values were reported for the Hip Injury and Osteoarthritis Outcome Score, Copenhagen Hip and Groin Outcome Score, International Hip Outcome Tool-12, visual analog scale, Nonarthritic Hip Score, Short Form-36, University of California, Los Angeles score, and Western Ontario and McMaster Universities Osteoarthritis Index.
Researchers noted that most included studies reported clinically meaningful improvement following hip arthroscopy and high levels of patient satisfaction. However, threshold values varied across studies because investigators used different calculation methods, including anchor-based, distribution-based, receiver operating characteristic, and proportional approaches. The authors said this methodological variability should be considered when interpreting reported MCID, PASS, SCB, and MIC values. They also emphasized that these thresholds may help physicians determine whether postoperative changes are meaningful to patients rather than simply statistically detectable, but they should not be applied as universal cutoffs across all patient populations. Interpretation should consider the outcome measure used, baseline symptom severity, follow-up duration, patient expectations, activity level, and the method used to derive the threshold.
The authors acknowledged several limitations. The included studies were heterogeneous with respect to patient populations, study design, surgical techniques, rehabilitation protocols, follow-up intervals, outcome measures, and statistical methods. No randomized controlled trials met the eligibility criteria, and the reported threshold values represent arithmetic averages from published studies rather than pooled meta-analytic estimates. The lack of formal heterogeneity analyses and language restrictions may also limit the generalizability of the findings.
Overall, the review provides reference values that may help physicians interpret patient-reported outcomes following hip arthroscopy for femoroacetabular impingement. However, the authors emphasized that these thresholds should be interpreted cautiously and, whenever possible, calculated within individual study cohorts rather than applied universally.
“The MCID, PASS, SCB, and MIC calculated values are valuable for future hip arthroscopy trials in patients with FAI. However, given the heterogeneity of the included studies, their predominantly nonrandomized design, and differences in PROMs, follow-up intervals, and calculation methods, these findings should be interpreted cautiously,” wrote lead study author Filippo Migliorini, of the Department of Trauma and Reconstructive Surgery, University Hospital of Halle, Martin-Luther University Halle-Wittenberg, Germany, and colleagues.
Disclosures: The authors reported no competing interests.