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

Male Sex, Revision Surgery, Low Volume of Anterior Cruciate Ligament Remnant, and Significant Instability Are Risk Factors for Posterior Root Tear of the Lateral Meniscus in Patients Undergoing Anterior Cruciate Ligament Reconstruction

PURPOSE

To determine the incidence of lateral meniscus posterior root tears (LMPRTs) in patients undergoing anterior cruciate ligament (ACL) reconstruction and identify associated risk factors.

METHODS

We conducted a retrospective, multicenter study using data from the Francophone Arthroscopic Society's registry. The study included all the patients in the registry who underwent ACL reconstruction surgery between June 2020 and June 2023; we excluded incomplete data. We compared delay from injury to surgery between LMPRTs group and no-LMPRTs group. Variables investigated as potential risk factors for LMPRTs included age, sex, nature of surgery (primary or revision), pivot shift test result, side-to-side laxity under anesthesia, presence of ACL remnant, occurrence of medial meniscal tear, and presence of collateral ligament injury. Risk factors were analyzed using a logistic regression model.

RESULTS

Among the 5,359 patients analyzed, LMPRTs occurred in 7.0% (n = 375) of cases during ACL reconstruction. Mean age at surgery was 29.3 ± 10.3 years old [11-77]. Concerning delay to surgery, the mean time was 8.4 ± 23.1 weeks [0.0-347.2] in the no-LMPRTs group and 6.5 ± 10.2 weeks [0.2-61.6] in the LMPRTs group (P = .109). Univariate analysis revealed that male sex (P < .001), revision surgery (P < .001), medial meniscal injury (P = .007), ACL remnant (0% vs >70%, <10% vs >70%, 10%-30% vs >70%, >30%-50% vs >70%, >50%-70% vs >70%; P < .001), and greater pivot shift grade (P = .011) were significantly associated with a presence of LMPRTs. Age, side-to-side laxity, and collateral ligament injury were not found to be significant risk factors. In multivariate analysis, male sex, revision surgery, pivot shift test result, and a low volume of ACL remnant remained significant. Side-to-side laxity was also a significant factor in multivariate analysis.

CONCLUSIONS

This study identified male sex, revision surgery, low volume of ACL remnant, side-to-side laxity, and greater grade of pivot shift as significant risk factors for LMPRTs during ACL reconstruction.

LEVEL OF EVIDENCE

Level III, retrospective comparative case series.

Comparing Postoperative Outcomes of Isolated Anterior Cruciate Ligament Reconstruction and the "Terrible Triad" Anterior Cruciate Ligament Reconstruction With Medial Meniscus Ramp and Lateral Meniscus Root Repairs

Background

A new "terrible triad" has been reported to be an anterior cruciate ligament (ACL) tear with a concomitant medial meniscus ramp tear and lateral meniscus root tear. Patient-reported outcomes (PROs) for isolated ACL reconstruction (ACLR) versus an ACLR with concomitant medial meniscus ramp and lateral meniscus root repairs are not well known.

Purpose

To compare postoperative outcomes between isolated ACLR and ACLR with concomitant medial meniscus ramp and lateral meniscus root repairs.

Study Design

Cohort study; Level of evidence, 3.

Methods

An initial cohort of 1228 patients with ACLRs were retrospectively identified between April 2016 and November 2021. A total of 41 patients with isolated ACLR (isolated cohort) were age and sex matched to 41 patients who had an ACLR with concomitant medial meniscus ramp and lateral meniscus root repairs (triad cohort). Patients in the triad cohort were identified consecutively by date of surgery. Preoperative and ≥2-year postoperative PROs were evaluated to compare the isolated cohort with the triad cohort. Statistical analysis was performed with unpaired t tests and chi-square tests.

Results

Both the isolated cohort and triad cohort demonstrated significant differences between preoperative and postoperative PROs in all questionnaire categories assessed. Postoperative scores for the International Knee Documentation Committee (isolated, 88.8; triad, 86.2; P = .392), Cincinnati (isolated, 91.1; triad, 88.1; P = .295), and Lysholm (isolated, 92.1; triad, 90.1; P = .472) PROs demonstrated no significant differences between the cohorts. No significant difference was found between the isolated and triad cohorts for all preoperative questionnaire categories. Additionally, no significant difference was found in revision or reoperation rates between isolated and triad patients (P = .733).

Conclusion

No significant differences in PROs were found at minimum follow-up of 2 years postoperatively between the patients who underwent isolated ACLR (isolated cohort) and those who underwent ACLR with concomitant medial meniscus ramp and lateral meniscus root repairs (triad cohort). Inferior outcomes were not observed in the triad cohort when revision rates, reoperation rates, and postoperative PROs were compared. Given the optimistic short-term outcomes for isolated versus triad ACLR patients and the known biomechanical consequences of these untreated meniscal injuries, medial meniscus ramp and lateral meniscus root repairs should be performed when encountered concurrently with an ACL tear when possible.

Increased Posterior Tibial Slope Is Associated With Increased Risk of Meniscal Root Tears: A Systematic Review

BACKGROUND

While increased posterior tibial slope (PTS) is an established risk factor for anterior cruciate ligament tears, the association between tibial slope and meniscal posterior root tears is not well-defined.

PURPOSE

To summarize the available literature evaluating the association between PTS and meniscus root injuries compared with patients without root tears.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A literature search was performed using the Scopus, PubMed, and Embase databases. Human clinical studies evaluating the associations between the medial tibial slope (MTS), lateral tibial slope (LTS), lateral-to-medial (L-to-M) slope asymmetry, and the risk of meniscus root tears were included. Patients with medial meniscus posterior root tears (MMPRTs) and lateral meniscus posterior root tears (LMPRTs) were compared with a control group without root injury. Study quality was assessed using the methodological index for non-randomized studies criteria.

RESULTS

Ten studies with 1313 patients were included (884 patients with root tears; 429 controls). The LMPRT subgroup (n = 284) had a significantly greater LTS (mean ± SD, 7.3°± 1.5° vs 5.7°± 3.91°; P < .001), MTS (5.26°± 1.2° vs 4.8°± 1.25°; P < .001), and increased L-to-M asymmetry (2.3°± 1.3° vs 0.65°± 0.5°; P < .001) compared with controls. The MMPRT group (n = 600) had significantly increased MTS relative to controls (8.1°± 2.5° vs 4.3°± 0.7°; P < .001). Furthermore, there was a higher incidence of noncontact injuries (79.3%) and concomitant ramp lesions (56%) reported in patients with LMPRT.

CONCLUSION

Increased MTS, LTS, and L-to-M slope asymmetry are associated with an increased risk of LMPRTs, while increased MTS is associated with MMPRTs. Surgeons should consider how proximal tibial anatomy increases the risk of meniscus root injury.

Posterior Lateral Meniscal Root Repair Through Lateral Tunnel and Anterior Cruciate Ligament Revision: How to Avoid Tunnel Overlapping

Posterior lateral meniscal root (PLMR) tears are commonly observed in conjunction with anterior cruciate ligament (ACL) injuries. The presence of PLMR tears exacerbates knee instability, increasing stress on ACL grafts and accelerating joint degeneration if left untreated. Anatomical repair of PLMR tears is therefore crucial for restoring native knee kinematics and reducing tibiofemoral contact pressures, thereby safeguarding the ACL graft. However, the standard use of a single medial tunnel approach for concomitant PLMR and revision ACL reconstruction may require reconsideration to prevent the potential risks of tunnel overlapping, which could undermine graft anatomical integrity. This article, to prevent the risk of tunnel overlapping, introduces a surgical approach that employs an additional lateral tibial tunnel for PLMR repair, instead of the typically used single medial one, for PLMR repair during simultaneous revision ACL reconstruction.

Treatment of an Iatrogenic Lateral Meniscal Root Tear After ACL Reconstruction

Background

The meniscal roots are essential for preserving the structural and biomechanical properties of the tibiofemoral joint. Posterior meniscal root avulsions can cause meniscal extrusion, joint space narrowing, and progressive knee arthritis. Iatrogenic avulsions after malpositioning of the transtibial tunnels during anterior cruciate ligament (ACL) reconstruction have previously been reported in the literature to account for poor long-term outcomes seen in some patients following ACL reconstruction. Therefore, correct transtibial tunnel placement during ACL reconstruction is essential to avoid iatrogenic meniscal damage.

Indication

Patients are indicated for surgery when presenting with a verified, symptomatic, complete meniscal root tear seen on advanced imaging or diagnostic arthroscopy. Contraindications for a root repair include the development of advanced osteoarthritis in the ipsilateral compartment, older age, and malalignment in the affected compartment.

Technique Description

The ACL graft was appreciated and noted to be vertical and posterior relative to its native anatomical position, violating the lateral posterior horn root attachment. A full lateral posterior meniscal root avulsion was then confirmed directly adjacent to the graft tunnel. A curette was used to prepare the footprint of the lateral meniscal root on the posterolateral tibia for the 2-tunnel transtibial pull-out tunnels, and a grasper was used to position the torn meniscal root back into its anatomical site. Two ultrabraided sutures were passed through the posterior horn of the lateral meniscus using a suture passer. These were then passed through the tunnels into the body of the meniscal root and reduced to its native anatomical position. The suture repair was then secured over an Endobutton Fixation Device at 90° of knee flexion through each tunnel into its native anatomical position while confirming its adequate tension by viewing arthroscopically.

Results

Within 2 years postoperatively, patients are expected to have improved overall knee-specific quality of life, reduced pain, and a successful return to activities.

Discussion/Conclusion

This injury underscores the importance of an accurate tibial tunnel placement during ACL reconstruction to avoid posterior meniscal root injuries and other associated complications. Physicians should consider such pathology in the differential diagnosis of patients presenting with persistent pain and instability following a primary ACL reconstruction.

Patient Consent Disclosure Statement

The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.