Factors Associated With Clinically Significant Patient-Reported Outcomes After Primary Arthroscopic Partial Meniscectomy.

PURPOSE: The purpose of this study was to establish minimal clinically important difference (MCID), substantial clinical benefit (SCB), and patient-acceptable symptom state (PASS) after meniscectomy and factors associated with achieving these goals.

METHODS: A prospectively maintained institutional registry was retrospectively reviewed for all patients undergoing isolated arthroscopic partial meniscectomy from 2014 through 2017. MCID, SCB, and PASS were calculated for the International Knee Documentation Committee (IKDC) and Knee Injury and Osteoarthritis Outcome Score (KOOS) subscores by using the anchor-based methodology and nonparametric receiver operating characteristic curves. Subscores included joint replacement (JR), physical function (PF), symptoms (Sx), pain, activities of daily living (ADL), sport, and quality of life (QOL).

RESULTS: A total of 269 patients were analyzed in the study, which reported outcomes between 6 and 7 months after surgery. The average age of our population was 48.9 ± 12.4 years. Twenty patients reported no change, 53 reported minimal improvement, and 137 reported substantial change after surgery; whereas 59 patients reported worse outcomes. One hundred seventy-seven patients were satisfied and 92 were not satisfied with the outcome of surgery. Established MCID/SCB/PASS for the IKDC, KOOS JR, KOOS PF, KOOS Sx, KOOS Pain, KOOS ADL, and KOOS QOL were 10.6/25.3/57.9, 10.7/13.2/68.3, -8.2/-11.3/26.2, 8.9/7.1/71.4, 9.7/22.2/76.4, 11.0/16.9/89.0, 12.5/27.5/55.6, and 15.6/34.4/46.9, respectively. Higher preoperative scores were associated with reduced odds of achieving MCID and SCB but greater odds of achieving PASS for nearly all scores (P < .05). Workers' compensation status, degenerative tears, medial-sided tears, and root tears were associated with reduced odds of achieving 2 or more clinically meaningful outcomes in 2 or more scores (P < .05).

CONCLUSIONS: Clinically meaningful outcomes were established by patient self-assessment. Variables associated with achieving these outcomes include preoperative score (positively correlated with MCID/SCB, negatively correlated with PASS); workers' compensation; degenerative, medial-sided tears; and root tears (remaining negatively correlated with MCID/SCB/PASS). These variables should be accordingly measured for confounding in future outcome reporting.