Long-Term Clinical and Radiographic Follow-Up of Total Resection for Discoid Lateral Meniscus

Purpose: The purpose of this retrospective study was to analyze the effects of age at surgery on the clinical results, arthritic progression, and changes in lower limb alignment during long-term follow-up of total resection for discoid lateral meniscus. Methods: A total of 37 knees in 32 patients were reviewed as a whole group and also after division into the following 3 groups according to the age at surgery: group A, 11 knees in patients aged less than 20 years; group B, 13 knees in patients aged 20 to 39 years; and group C, 13 knees in patients aged greater than 39 years. The mean age at surgery was 31.2 years (range, 9 to 52 years), and the mean length of follow-up was 14.5 years (range, 10 to 22.4 years). Results: According to the scale of Ikeuchi, clinically excellent or good results at the final follow-up were found in 84% of the knees in the whole group, 91% of those in group A, 85% of those in group B, and 77% of those in group C. Moderate or severe narrowing of the lateral joint space was seen in 11% of the knees in the whole group, 0% of those in group A, 8% of those in group B, and 23% of those in group C. In an analysis of lower limb alignment, statistically significant postoperative lateral shifts of Mikulicz’s mechanical axis were observed in groups B and C. Conclusions: The clinical results were satisfactory and the postoperative arthritic changes were mild in patients aged under 40 years. However, it is necessary to carefully monitor arthritic progression in patients who are aged over 19 years and have valgus deformities, because most of the knees in patients above this age became more valgus postoperatively. Level of Evidence: Level IV, prognostic case series.