Introduction <p>Hip arthroscopy has been established as a successful management for femoroacetabular impingement (FAI) syndrome. Patient-reported outcome measures (PROMs) are frequently used to assess treatment results in patients. However, clinically important outcome values have recently been calculated to better understand and interpret PROMs and define successful treatment. This systematic review aimed to investigate the minimal clinically important difference (MCID), patient-acceptable state (PASS), substantial clinical benefit (SCB), and minimally detectable change (MIC) of the most commonly used PROMs for assessing patients who have undergone arthroscopic surgery for FAI.</p> Material and methods <p>This study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses: the 2020 PRISMA statement. In October 2025, the following databases were accessed: PubMed, Web of Science, and Embase. All clinical studies investigating tools to assess the clinical relevance of PROMs used to evaluate patients who have undergone arthroscopic surgery for FAI were accessed. Only studies that assessed the minimal MCID, PASS, SCB, and/or MIC were considered.</p> Results <p>The methodological quality of the 21 included studies was assessed, and the overall risk of bias was found to be low-to-moderate. The main characteristics of the included studies were analyzed and summarized. In addition, we determined the MCID, PASS, SCB, and MIC of the hip injury and osteoarthritis outcome score (HOOS), short form 36 (SF-36), modified Harris hip score (mHHS), nonarthritic hip score (NASH), Copenhagen hip and groin outcome score (HAGOS), hip outcome score (HOS), international hip outcome tool-12 (iHOT-12), international hip outcome tool-33 (iHOT-33), University of California, Los Angeles Score (UCLA), visual analogue scale (VAS), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores for arthroscopic hip surgery.</p> Conclusions <p>This systematic review provides clinically important outcome values, such as the MCID, PASS, SCB, and MIC, for the most commonly used PROMs in arthroscopic hip surgery, based on data from 21 studies involving 5687 patients. The calculated values for the MCID, PASS, SCB, and MIC could be helpful for future clinical trials investigating the outcomes of hip arthroscopy in patients with FAI. However, given the heterogeneity of the included studies, their predominantly nonrandomized designs, and differences in PROMs, follow-up intervals, and calculation methods, these findings should be interpreted with caution.</p> <p><i>Level of evidence</i> Level IV, systematic review.</p>