Differences in the Association Between Medial Meniscus Tears and Focal Cartilage Lesions According to Tear Configuration.

Background: There are no statistical analyses on the association between the configuration of medial meniscus tears and the location of focal cartilage lesions.

Purpose: To investigate the association between the configuration of medial meniscus tears and focal cartilage lesions and analyze whether the location of medial meniscus tears corresponds with that of focal cartilage lesions.

Study design: Cross-sectional study; Level of evidence, 3.

Methods: The authors retrospectively evaluated the medical records of 317 patients with isolated medial meniscus tear who underwent arthroscopic surgery from January 2016 to December 2020. The configuration of the medial meniscus tear was determined based on the International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine (ISAKOS) classification. Patients with flap, radial, and longitudinal tears were included in the vertical tear group. For subgroup analysis, vertical tears were divided into medial meniscus posterior root tears and remaining tears. The location of the medial meniscus tear was categorized as anterior, middle, or posterior according to the ISAKOS classification. The cartilage of the medial femoral condyle (MFC) and that of the medial tibial condyle (MTC) were divided into 6 and 4 zones, respectively, and the location of cartilage lesions on the MFC and MTC was evaluated by preoperative magnetic resonance imaging.

Results: There was a higher incidence of focal cartilage lesions with vertical versus horizontal medial meniscus tears (P < .001). For middle and posterior vertical tears with focal cartilage lesions, there was a significant concordance in location between the tear and the lesion (P < .001). In a subgroup analysis of medial meniscus posterior root tears, there was significantly more discordance in location between the tear and the lesion with medial meniscus posterior root tears (23/26 tears; 88.5%) compared with the remaining vertical tears (60/177 tears; 33.9%) (P < .001); instead, the focal cartilage lesions were mainly distributed in the lateral anterior and central portions of both the MFC and MTC.

Conclusion: Vertical tears of the medial meniscus were significantly associated with the presence of focal cartilage lesions, whereas horizontal tears were not. Additionally, middle and posterior vertical tears with focal cartilage lesions showed significant concordance in location between the tear and the lesion.