Poster 234: Establishing the Minimal Clinically Important Difference and Patient Acceptable Symptomatic State After Isolated Arthroscopic Posterior Medial Meniscal Root Repair

Abstract

Objectives:

Root tears encompass avulsion injuries affecting the bony or soft tissue root attachments of the meniscus, as well as radial tears occurring within 1 cm of these attachment points. Meniscal root tears have been increasingly recognized as contributors to early onset osteoarthritis and disrupted joint kinematics and insights from animal, cadaveric, and clinical studies have resulted in a paradigm shift from meniscectomy towards repair. The purpose of this study is to define the minimal clinically important difference (MCID) and patient-acceptable symptomatic state (PASS) for patient-reported outcome measures (PROMs) following isolated posterior medial meniscal root repair (PMMR) and to investigate the role of preoperative, demographic, and intraoperative variables for predicting achievement of these thresholds. We hypothesized that patients have a greater likelihood of achieving MCID with lower preoperative outcome scores and a greater likelihood to achieve PASS with higher preoperative outcome scores. Furthermore, certain preoperative and intraoperative factors are likely to influence achievement of MCID and PASS following PMMR.

Methods:

This is an IRB approved retrospective study of prospectively collected data from a single, high-volume institution. Inclusion criteria were patients who underwent arthroscopic PMMR performed by one of three fellowship-trained attending surgeons with a minimum of two year postoperative follow up. Exclusion criteria consisted of patient with KL grade >3 osteoarthritis and concomitant ligamentous procedures. Patients who had ipsilateral knee surgery within 2 years of undergoing meniscal root repair were also excluded. PROMs were collected from January 2017 to September 2023 and an electronic medical record was reviewed for demographic variables, intraoperative details, and postoperative complications. PROMs analyzed in this study include the International Knee Documentation Committee Score (IKDC), the Knee Injury and Osteoarthritis Outcome Score Jr. (KOOS Jr.) and the Veterans Rand 12 Physical Function (VR12 P). MCID was determined to be one-half the standard deviation of the difference from baseline in PROM scores at minimum two-year follow-up. PASS thresholds were calculated using an anchor-based approach. Receiver operating characteristic (ROC) analysis for the calculation of PASS was conducted and optimal thresholds were calculated using the Youden Index to maximize the sensitivity and specificity of threshold values. Multivariate logistic regression analyses were conducted to identify patient-related factors at baseline and intraoperative variables associated with the attainment of MCID and PASS.

Results:

Seventy patients were included in the final analysis. The demographics of included patients is listed in Table 1. The mean preoperative score, mean postoperative score, MCID threshold, MCID achievement rate, PASS threshold, and PASS achievement rate for IKDC, KOOS Jr., and VR12 physical are listed within Table 2. The predictive value for all PASS thresholds was good to excellent, with AUC values for IKDC, KOOS Jr., and VR12 Physical being 0.858, 0.864, and 0.755, respectively (Figure 1). For IKDC, lower BMI (OR 0.73, p = 0.03) and lower preoperative score (OR 0.94, p = 0.02) were predictive of MCID achievement, whereas lower BMI (OR 0.87, p < 0.01) and greater preoperative score (OR 1.04, p = 0.04) were predictive of PASS achievement. For KOOS Jr., use of two sutures (OR 6.98, p < 0.01) was predictive of MCID achievement, whereas use of two sutures (OR 6.91, p < 0.01) and lower BMI (OR 0.81, p < 0.01) were predictive of PASS achievement. For VR12 Physical scores, younger age (OR 0.92, p = 0.04), lower BMI (OR 0.84, p = 0.01), and lower preoperative score (OR 0.89, p < 0.01) were predictive of MCID achievement, whereas use of two sutures (OR 7.24, p = 0.02), lower BMI (OR 0.92, p < 0.01), and greater preoperative score (OR 1.19, p = 0.02) were predictive of PASS achievement.

Conclusions:

This study defines the thresholds for MCID and PASS achievement at minimum two-year follow-up for IKDC, KOOS Jr., and VR12 Physical scores in a large cohort of patients undergoing isolated posterior-medial meniscal root repair at a single, high-volume institution. More patients achieved MCID than PASS. Lower BMI, use of fewer sutures, and preoperative scores were the most common predictors of MCID and PASS achievement. Additionally, younger age was an independent predictor of MCID achievement for VR-12 Physical Function.