Preoperative varus alignment and postoperative meniscus extrusion are the main long-term predictive factors of clinical failure of meniscal root repair

Abstract

Purpose: No studies have been conducted to determine long-term predictors of clinical failure after surgical root repair. This study identified long-term prognostic factors of clinical failure after pull-out repair of medial meniscus posterior root tears (MMPRTs) at a minimum of 10 year follow-up.

Methods: A total of 37 patients who underwent MMPRT pull-out repair and had been observed for more than 10 years were recruited for this study. The mean follow-up period was 125.9 ± 21.2 months. Clinical failure of the procedures was defined as conversion to total knee arthroplasty (TKA). Participants were categorized into two groups: non-failure and failure groups. Various factors, including demographic features and radiologic findings, were analyzed and compared between the two groups. Meniscus extrusion was assessed at coronal magnetic resonance imaging preoperatively and 1 year postoperatively. Independent risk factors were determined by univariate analysis and logistic regression analysis. To determine the cut-off value for risk factors, the receiver-operating characteristic curve analysis was performed.

Results: In total, eight patients (22%) were converted to TKA during the follow-up period. With univariate analysis, statistically significant differences between two groups were observed in mechanical varus alignment (P = 0.018), rate of the number of patient with more meniscal extrusion values after surgery (P = 0.024), and the difference between the preoperative and 1-year postoperative value of meniscus extrusion (mm) (P = 0.010). In a logistic analysis, OR of mechanical varus alignment and differences in meniscus extrusion value before and 1 year after surgery was 1.5 (P = 0.048) and 3.7 (P = 0.034). The cut-off values of mechanical varus alignment and differences in meniscus extrusion values were 5 degrees and 0.7 mm.

Conclusion: Clinically, preoperative varus alignment and increased meniscal extrusion after surgery were found to be predictive for a clinical failure after meniscal root repair in a long-term perspective. Thus, these negative prognostic factors should be taken into consideration for performing root repair in MMPRTs.

Level of evidence: Level III.

Keywords: Knee; Meniscus; Prognostic factors; Pullout repair; Root tear.