Posterior Horn Lateral Meniscal Oblique Radial Tear in Acute Anterior Cruciate Ligament Reconstruction Incidence and Outcomes After All-Inside Repair: Clinical and Second-Look Arthroscopic Evaluation

Abstract

Background: The term posterior horn lateral meniscal oblique radial tear (LMORT) has emerged to characterize the tear patterns of the lateral meniscus in many patients with acute anterior cruciate ligament (ACL) injury. There is a lack of data regarding the exact incidence according to the types of LMORT and clinical outcomes. Purposes: (1) To investigate the incidence of LMORT according to type in patients with acute ACL reconstruction (ACLR) and (2) to identify healing status after repair of LMORT via second-look arthroscopy and clinical outcomes. Study Design: Case series; Level of evidence: 4. Methods: Patients who underwent primary ACLR within 6 months of injury were retrospectively reviewed. The LMORT was classified into 4 types based on the severity and distance from the root: type 1 (partial tear <10 mm from the root), type 2 (complete tear <10 mm from the root), type 3 (partial tear >10 mm from the root), type 4a (complete tear >10 mm from the root), and type 4b (type 4a with longitudinal tear at the meniscocapsular junction). Only patients with LMORT were isolated, and the clinical outcomes were compared according to the healing status of LMORT in second-look arthroscopy. Results: Of 635 patients with ACLR, LMORT was identified in 97 patients (15.3%), and type 4 LMORT accounted for the largest proportion (n = 62; 32.6%) of 190 lateral meniscal tears. In 79 patients with LMORT who satisfied the 2-year follow-up period, all patient-reported outcomes (PROs), including the Lysholm (preoperative, 64.1; postoperative, 88.2) and International Knee Documentation Committee subjective (preoperative, 50.5; postoperative, 82.9) scores, were significantly improved ( P < .001) 31.8 months postoperatively. Of the 61 patients who underwent second-look arthroscopy, 49 (80.3%) were classified into the complete healing group. There was no significant difference in postoperative PROs between the complete and partial healing groups. Conclusion: The incidence of LMORT was 15.3% in patients with acute ACL injury, and type 4 LMORT was the most common type. Complete healing of LMORT was achieved in 80.3% of patients who underwent second-look arthroscopy, and the PROs were significantly improved postoperatively. Good clinical results can be achieved if the LMORT is repaired as much as possible during ACLR.

Outcomes of Lateral Meniscal Oblique Radial Tear Repair Compared With Intact Meniscus After ACL Reconstruction: A Cohort Study

“…A recent series of 79 patients with minimum 2-year follow-up who underwent ACLR with LMORT repair reported a mean sIKDC score of 82.9. 11 A high activity level was maintained by patients in both groups in the current study, and the Tegner scores in our cohort were comparable with those of previously published series. Sonnery-Cottet et al 38 reported a mean Tegner score of 6.4 in patients undergoing iACLR.…”

“…2,35,36 These findings suggest that ACL graft integrity could be compromised from a failure to repair the meniscus. 8 Regarding healing of these tears, second-look arthroscopy in LMORT tears as described by Jeon et al 11 showed 80.3% complete healing status and 19.7% partial healing status in 61 repaired LMORTs. As a substantial portion of the tear crosses obliquely through the red-red and red-white zones of the meniscus and repair is occurring during the time of ACLR, there is ample vascularity and stimulus to encourage healing of these tears when combined with anatomic repair.…”

“…A 2022 study by Jeon et al 11 reported a complete healing rate of 80.3% in LMORTs with second-look arthroscopy. Similarly, a recent systematic review of lateral meniscal repairs in the setting of ACLR that included several of these studies found a complete or partial healing rate of 93.6%.…”

“…These reports are similar to other studies regarding the reoperation rates of iACLR with the literature overall demonstrating a reoperation rate of 10% to 26% at mid-to long-term follow up. 31,40 A 2022 study by Jeon et al 11 reported a complete healing rate of 80.3% in LMORTs with second-look arthroscopy.…”

“…A recent series of 79 patients with minimum 2-year follow-up who underwent ACLR with LMORT repair reported a mean sIKDC score of 82.9. 11…”