Results of Arthroscopic All-Inside Repair for Lateral Meniscus Root Tear in Patients Undergoing Concomitant Anterior Cruciate Ligament Reconstruction

Purpose: To evaluate the effectiveness of all-inside repair of posterior lateral meniscus root full-thickness tears with preoperative and postoperative magnetic resonance imaging (MRI) and to propose a system of classifying posterior lateral meniscus root tears. Methods: From June 2003 to March 2007, 27 (6.95%) of a consecutive series of 388 anterior cruciate ligament reconstructions had a concomitant posterior lateral meniscus root tear. Of the patients, 25 (92.6%) were followed up for a more than 1 year. There were 22 male and 3 female patients, with a mean age of 28.8 years. The mean timing of surgery after injury was 40.8 months. The preoperative and postoperative MRI scans were analyzed and compared. We classified posterior lateral meniscus root tears according to arthroscopic findings. Results: There was no postoperative effusion, joint-line tenderness, or positive McMurray provocation testing observed at the last follow-up. No statistically significant improvement was observed in the coronal plane in the 18 follow-up MRI scans (P = .096); however, sagittal extrusion improved significantly (P = .007). Posterior lateral meniscus root tears were classified based on arthroscopic findings: type I, oblique flap; type II, T shape; type III, longitudinal cleavage; or type IV, chronic inner loss. A type I tear was found in 7 patients, type II in 4, type III in 4, and type IV in 10. Conclusions: After repair of posterior lateral meniscus root tears, MRI showed that the displaced lateral meniscus was reduced, mainly in the sagittal plane. Posterior lateral meniscus root tears were classified based on arthroscopic findings: type I, oblique flap; type II, T shape; type III, longitudinal cleavage; or type IV, chronic inner loss. Level of Evidence: Level IV, therapeutic case series.