Increased Meniscal Extrusion at 1 Year After Surgery Is Associated With a Lower Likelihood of Substantial Mid-Term Patient-Perceived Improvement After Medial Meniscal Root Tear Repair

Abstract

Purpose: To analyze factors influencing achievement of mid-term substantial clinical improvement after surgical repair of medial meniscal root tears (MMRTs).

Methods: Patients who underwent arthroscopic pullout repair of MMRTs between 2010 and 2018 with minimum 5-year follow-up were reviewed. Patients were classified into 2 groups based on achieving substantial clinical improvement at 5 years using published substantial clinical benefit (SCB) values: Group 1 showed improvement beyond the SCB thresholds in both the International Knee Documentation Committee subjective score and Lysholm score, whereas group 2 did not reach the SCB threshold for one or both scores. Additionally, secondary grouping was performed using minimal clinically important difference (MCID) values based on the same criteria as SCB grouping. Comparative analyses were performed for both groupings, followed by regression analyses to identify factors influencing achievement of clinical improvement. In particular, SCB-based regression analyses were performed using multiple models with adjusted SCB thresholds.

Results: Of 64 patients, 22 (34.4%) achieved SCB-level improvement and 36 (56.3%) achieved MCID-level improvement at 5 years postoperatively. Age, postoperative medial meniscal extrusion (MME) at 1 year, and preoperative-to-postoperative difference in MME were significantly higher in group 2 patients than in group 1 patients (P = .005, P = .013, and P = .047, respectively). Group 2 also exhibited higher Kellgren-Lawrence grades and greater progression of Kellgren-Lawrence grades at 5 years postoperatively (P = .003 and P = .015, respectively). Subsequently, perioperative variables showing differences in between-group comparisons were included in the SCB-based regression analyses, with postoperative MME consistently identified across all models as a factor influencing the achievement of mid-term clinical improvement after surgical repair of MMRTs (P = .015, P = .034, and P = .014 in models 1, 2, and 3, respectively). The analysis based on secondary grouping using MCID values showed consistent results.

Conclusions: The number of patients who perceived substantial clinical improvement 5 years after surgical repair of MMRTs was relatively small. Notably, increased MME at 1 year postoperatively was associated with a lower likelihood of achieving patient-perceived substantial clinical improvement at 5 years.

Level of evidence: Level IV, retrospective prognostic case series.