Establishing the Minimal Clinically Important Difference and Patient Acceptable Symptom State After Isolated Arthroscopic Posterior Medial Meniscal Root Repair.

Background: Significant clinical improvements have been shown after a posterior medial meniscal root (PMMR) repair; however, there is a lack of understanding of their effect on patients' perspectives.

Purpose: To (1) define the minimal clinically important difference (MCID) and the Patient Acceptable Symptom State (PASS) for patient-reported outcome measures (PROMs) after isolated PMMR repair; (2) investigate the role of preoperative, demographic, and intraoperative variables in predicting achievement of these thresholds.

Study design: Case series; Level of evidence, 4.

Methods: Patients who underwent arthroscopic PMMR with a minimum of 2-year postoperative follow-up were included. PROMs, demographic variables, intraoperative details, and postoperative complications were recorded. PROMs analyzed include the International Knee Documentation Committee (IKDC) Score, the Knee injury and Osteoarthritis Outcome Score Jr (KOOS Jr), and the Veterans RAND 12 Physical Function (VR12 PF). MCID and PASS thresholds were calculated. Multivariate logistic regression analyses were conducted to identify factors associated with the attainment of the MCID and the PASS.

Results: A total of 75 patients were included, and 5 progressed to arthroplasty within 2 years. Of the remaining patients, the MCID thresholds and percentage achievements were as follows: the IKDC, 10.17 and 84.3%; the KOOS Jr, 10.42 and 71.4%; and the VR12 PF, 6.08 and 60%. The PASS thresholds and percentage achievements were as follows: the IKDC, 67.81 and 60%; the KOOS Jr, 71.95 and 55.7%; and the VR12 PF, 47.75 and 52.9%. For the IKDC, a lower body mass index (BMI) and a lower preoperative score were predictive of MCID achievement, whereas a lower BMI and a greater preoperative score were predictive of PASS achievement. For the KOOS Jr, a lower BMI was predictive of PASS achievement. For the VR12 PF, younger age, lower BMI, Kellgren-Lawrence (KL) grade 1, and a lower preoperative score were predictive of MCID achievement, whereas lower BMI, greater preoperative joint space, KL grade 1, and a higher preoperative score were predictive of PASS achievement.

Conclusion: This study defines the thresholds for MCID and PASS achievement at a minimum 2-year follow-up for the IKDC, KOOS Jr, and VR12 PF scores in a cohort of 70 patients undergoing isolated PMMR repair (72.9% women, mean age, 55.2 years). A larger portion of patients achieved the MCID (84.3%, 71.4%, and 60%) compared with the PASS (60%, 55.7%, and 52.9%). The most common predictors of MCID and PASS achievement included lower BMI and preoperative scores. Furthermore, younger age emerged as an independent predictor of MCID achievement for VR12 PF.