Clinical relevance of patient-reported outcome measures in the surgical management of focal chondral defects of the knee: a systematic review.

INTRODUCTION

To evaluate clinical outcome following surgical management of focal chondral defects in the knee, patient-reported outcome measures (PROMs) are used. To give these measures meaning, parameters such as the minimal clinically important difference (MCID), patient-acceptable symptom state (PASS), minimally detectable change (MDC), clinically important difference (CID) and substantial clinical benefit (SCB) have been introduced. This systematic review investigated the MCID, SCB, CID, PASS and MDC of the most commonly used PROMs for assessing patients following surgical repair of focal chondral defects of the knee.

METHODS

This systematic review was conducted in accordance with the 2020 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and the recommendations of the Cochrane Handbook for Systematic Reviews of Interventions. All clinical studies investigating tools to assess the clinical relevance of PROMs in the surgical repair of focal chondral defects of the knee were reviewed. In April 2025, the following databases were accessed: PubMed, Web of Science and Embase. The PROMs of interest included: the International Knee Documentation Committee (IKDC) questionnaire, the Knee Injury and Osteoarthritis Outcome Score (KOOS) and its related subscales activities of daily living (ADL), pain, quality of life (QoL), sports and recreational activities, and symptoms, the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) score, the Tegner Lysholm knee scoring scale, the Short Form-12 (SF-12) and its related mental and physical component subscales, the Short Form-36 (SF-36) and the Cincinnati Knee Rating System (CKRS). The Risk of Bias in Nonrandomised Studies of Interventions (ROBINS-I) indicated a low to moderate risk of bias.

RESULTS

The systematic literature search yielded 524 articles. Only data from four studies (involving 421 patients) were included. All of these were non-randomised controlled trials (RCTs) employing a retrospective study design. Most reported thresholds for a significant change across the questionnaires ranged from 20 to 30 points on a 100-point scale, whereas PASS values ranged from 62 points in the IKDC to 87 points in the KOOS ADL.

CONCLUSIONS

Despite a comprehensive search strategy, only four studies met the inclusion criteria, underscoring that the parameters analysed remain overlooked in the scientific literature. Reported results for MCID, CID and MDC following cartilage repair are relatively consistent in magnitude, ranging from 10 to 20. Differences reported in the literature that fall below this range should be regarded as no improvement. For SCB and PASS, values were even higher, spanning from 20 to 30 and from 62 to 87 points in IKDC and KOOS ADL, respectively. Given the high standard of modern medical care, further development and validation of condition-specific PROMs should be considered to facilitate future clinical evaluations using PROMs.

LEVEL OF EVIDENCE: Level III, systematic review.