Lateral Meniscal Oblique Radial Tears Are Common With ACL Injury: A Classification System Based on Arthroscopic Tear Patterns in 600 Consecutive Patients

Abstract

Background: Meniscal root tears and ramp lesions have been rigorously characterized in recent literature. However, one of the most common lateral meniscal injuries identified with an acute anterior cruciate ligament (ACL) disruption, a posterior horn lateral meniscal oblique radial tear (LMORT), has not been thoroughly described. Purpose: To determine the incidence of all meniscal tears and, more specifically, the incidence of posterior horn LMORTs in a multicenter cohort of consecutive, acute ACL reconstructions. Additionally, the authors aimed to develop a new classification system to help guide treatment of posterior horn LMORTs. Study Design: Cross-sectional study; Level of evidence, 3. Methods: A multicenter retrospective cohort design was used to analyze 200 consecutive cases of acute ACL reconstruction from each of 3 different surgeons, for a total of 600 patients. The operative notes and intraoperative photos were analyzed to determine the incidence and laterality of all meniscal tears. A classification system based on tear characterization was then used to categorize tear patterns into similar groups. Results: A total of 396 (66%) of the 600 patients with acute ACL disruption had concomitant meniscal tears. Specifically, 187 (31%) had a lateral meniscal injury, 89 (15%) had a medial meniscal injury, and 122 (20%) had both medial and lateral meniscal injuries. The most common lateral meniscal tear was an LMORT; 71 (18%) patients with meniscal tears had a posterior horn LMORT. Overall, the incidence of ACL injury with a concomitant posterior horn LMORT was 12%. A classification was developed, which included type 1 tear (partial thickness <10 mm from the root attachment), type 2 tear (complete radial oblique tear that extended <10 mm from root), type 3 tear (incomplete LMORT that extended >10 mm from root), and type 4 tear (complete LMORT >10 mm from root). Conclusion: In 600 consecutive acute ACL reconstructions, the incidence of concomitant ACL injury with meniscal injury was 66%, and posterior horn LMORTs represented a large proportion of all meniscal tears (12%). A classification scheme was developed for posterior horn LMORTs to aid reporting and clinical decision making for these common tears.

Higher Incidence of Complete Lateral Meniscal Root Tears in Revision Compared With Primary Anterior Cruciate Ligament Reconstruction

“…The PACLR LMPRT repair incidence is consistent with findings of prior studies, which have reported 7% to 14% rates of lateral meniscal posterior root injuries concurrent with ACL tears. [9][10][11] However, some of these were imaging-based studies and did not differentiate partial lesions or stable tears that may not need repair as compared with unstable, complete tears that were repaired in our patients. A study by Ahn et al 21 reported a 6.95% incidence of concomitant LMPRTs that required repair at the time of ACLR.…”

“…This article was a podium presentation (under the title "Incidence of Lateral Meniscus Root Tears in Revision Versus Primary ACL posterior root tears (LMPRTs) with ACL ruptures. [9][10][11] One study associated male sex and a contact mechanism of injury with LMPRTs in patients with ACL injury. 12 These tears are frequently located within the posterior horn at or near the meniscal root.…”

All-Inside Repair for Radial Tear at the Posterior Horn of the Lateral Meniscus: A Figure-8 Suture Technique

“…The radial lateral meniscus tear at the posterior horn is frequently accompanied by an anterior cruciate ligament injury. 4 While the affected leg is placed in a tailor's leg position, an anteromedial portal is created for inserting a hook probe. Then, the radial Fig 1 . A radial tear at the posterior horn of the lateral meniscus in left knee.…”

“…Even all-inside meniscal repair techniques with penetrating posterior capsules by suture needles still have a risk of neurovascular injury 3 ; hence, a pure all-inside procedure that keeps the posterior joint capsule intact is adapted as a favorable method at the site. In practice, although all-inside repair procedures at the posterior horn of the lateral meniscus were usually introduced with horizontal sutures techniques, 4 , 5 a horizontal suture is less reliable for maintaining enough reduction in a biomechanical study. 6 Currently, we present a new, simple all-inside lateral meniscal repair technique of the radial tear at the posterior horn that requires no added accessory portal.…”

Good Surgical Outcomes After Concomitant Repair of Double Radial Tears of the Lateral Meniscus and Anterior Cruciate Ligament Reconstruction

“…An all-inside technique is preferred for a LMORT near the root (Fig 4). 7 Postoperative rehabilitation consisted of nonweightbearing for 6 weeks, with range of motion (ROM) limited from 0 to 90 for the first 4 weeks. Return to jogging was typically delayed until 4 to 6 months after surgery, and return to sport was typically achieved at 9 months from surgery.…”