Ideal remaining meniscus width and risk factors for decrease in meniscus width after reshaping surgery in pediatric patients with discoid lateral meniscus.

Abstract

This study aimed to determine the ideal remaining discoid meniscal width after reshaping surgery and to investigate the preoperative risk factors for changes in the meniscal width. Twenty-nine pediatric patients (39 knees) who underwent arthroscopic reshaping for symptomatic discoid lateral meniscus (DLM) were retrospectively analyzed. MRI was performed postoperatively and at 6 months or 1-2 years. Changes in meniscal width were measured, and logistic regression and receiver operating characteristic (ROC) curve analyses identified risk factors and cut-off values. The meniscal width gradually decreased, particularly in the midbody (25.7 % at 6 months and 38.1 % at 1-2 years, postoperatively). Risk factors for width reduction included a complete-type DLM (β = 26.0, P = 0.036) and a smaller preoperative meniscal height (β = -4.51, P = 0.048). The ROC curve analysis indicated that a preoperative meniscal height of ≤ 3.3 mm and preserving a meniscal width of ≤ 8.5 mm after surgery may result in a residual meniscal width of less than 5 mm. The ideal remaining meniscal width after reshaping surgery should be > 8.5 mm to minimize the risk of postoperative degeneration. Surgeons should consider preserving additional meniscal tissue, especially in patients with risk factors such as complete DLM or a meniscal height of less than 3.3 mm, to improve long-term joint preservation.