Discoid Lateral Meniscus Incidence During Knee Arthroscopy

Discoid meniscus is a morphological anomaly of the lateral meniscus that appears in 1–5% of meniscectomies. A precise diagnosis remains difficult to make, and many dilemmas hinder effective treatment.

To evaluate the incidence of discoid meniscus in patients who underwent knee arthroscopy, as well as the discoid meniscus type, follow-up problems, combined knee lesions, and postoperative results.

This retrospective study included 1357 patients who received knee arthroscopy during the period between January 2007 and December 2013. We analysed the discoid meniscus incidence, sex distribution, type distribution (Monllau classification), noted preoperative symptomatology, rupture incidence and type (O’Connor classification), anomaly presence and other intra-articular lesion correlations. The IKDC score was used to evaluate the operative treatment results.

The DLM incidence was 1.03%. The most common type of discoid meniscus was complete 5 (35.71 %). The dominant symptom was pain, which was reported by 12 (85.71%) patients. Eleven (78.57 %) patients exhibited ruptures, and the most common type was horizontal, which was reported in 4 (36.36%) cases. The number of ruptures was significantly higher in patients older than 18 (9 patients; 90%), compared to those younger than 18 (2 patients; 40%). Operative treatment resulted in an improvement for all patients in terms of subjective symptom reduction.

The incidence of DLM in our study was 1.03%, and the dominant symptom was pain in the knee (85.71%). The most common lesion of the meniscus was a horizontal split, primarily in patients older than 18 years. Patients also presented with joint intra-articular lesions; the most common type was ACL rupture. In all patients, an improved postoperative IKDC score was reported.