Inconsistencies in clinically significant outcome metrics for knee cartilage repair: a systematic review

To systematically review the variability of reporting of clinically significant outcomes (CSOs) including minimal clinically important difference (MCID), substantial clinical benefit (SCB) and patient acceptable symptom state (PASS), and threshold calculation methods following surgical treatments for cartilage defects of the knee. A systematic review was performed using the 2020 Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines. A literature search was performed on August 12th, 2024, using the PubMed, Embase, and Scopus online databases for human clinical studies with publication dates ranging from 2010 to 2024 reporting on MCID, SCB, or PASS following surgical treatments for cartilage defects of the knee. Study demographics, patient-reported outcome measures (PROMs), CSO thresholds, and methods of CSO calculation were collected. A total of 19 studies (n = 3659 patients) with an average follow-up of 36.5 months were included. A total of 14 (93.3%) studies reported MCID, six (31.8%) studies reported SCB, and five (26.3%) studies reported PASS. Of the included studies, 16 (80%) referenced another study for calculating their CSO whereas three (20%) studies calculated their own CSO. A total of 16 different PROMs were reported among the included studies. Eight studies utilized the anchor-based method for CSO calculation, ten studies used both the anchor and the distribution-based methods for calculation, while only one study used the distribution-based method alone. There is considerable variation in the reporting and calculation methods of MCID, SCB, and PASS for different PROMs following surgical treatments for cartilage defects of the knee.Level of Evidence: IV, Systematic Review of Level I-IV studies.