Risk Factors for Lateral Meniscus Posterior Root Tears in the Anterior Cruciate Ligament–Injured Knee: An Epidemiological Analysis of 3956 Patients From the SANTI Study Group

Abstract

8Background: Lateral meniscal posterior root tears (LMPRT) result in loss of hoop forces 9 and significant increases in tibiofemoral contact pressures. Pre-operative imaging lacks 10 reliability and therefore holding an appropriate index of suspicion, based on the 11 epidemiology and risk factors for LMPRT, may reduce the rate of missed diagnoses. 12 Hypothesis/Purpose: The primary objectives of this study were to evaluate the incidence 13 and risk factors for lateral meniscus root lesions in a large series of patients undergoing 14 anterior cruciate ligament (ACL) reconstruction. 15 Study Design: Case series 16Methods: All patients who underwent primary or revision ACL reconstruction, between 17 January 2011 to April 2018 were considered for study eligibility. From this overall 18 population, all patients who underwent repair of a lateral meniscus posterior root tear 19 (LMPRT) were identified. The epidemiology of LMPRT was defined by the incidence 20 within the study population, stratified by key demographic parameters. Potentially 21 important risk factors for the presence of LMPRT were evaluated in multivariate logistic 22 regression analysis. 23Results: 3956 patients undergoing ACL reconstruction were included in the study. A 24LMPRT was identified and repaired in 262 patients (6.6%). Multivariate analyses 25 demonstrated that significant risk factors for LMPRT included a contact sports injury 26 mechanism (7.8% incidence with contact sports mechanism vs 4.5% with non-contact 27 mechanism 4.5%; OR = 1.69, IC95% 1.266 -2.285; P <.001) and the presence of a medial 28 meniscal tear (7.9% incidence with medial meniscal tear vs 5.8% in those without; OR = 29 1.532, IC95% 1.185 -1.979; P <.001). Although the incidence of LMPRT in male patients 30 (7.3%) was higher than females (4.8%) this was not significant in multivariate analysis (P 31 = 0.270). Patient age, revision ACL reconstruction and a pre-operative side to side laxity 32 difference of ≥ 6mm were not found to be significant risk factors for LMPRT. 33 Conclusion: The incidence of LMPRT was 6.6% in a large series of patients undergoing 34 ACL reconstruction. Participation in contact sports and the presence of a concomitant 35 medial meniscal tear were demonstrated to be important independent risk factors. Their 36 presence should raise the index of suspicion of this injury pattern. 37 38What is known about the subject: Previous reports on the epidemiology and risk factors 40 for LMPRT have all been limited by small study populations. This is an important 41 limitation because it reduces the confidence that can be held in the estimation of the true 42 incidence of these injuries. Understanding the epidemiology and risk factors for LMPRT 43 is of paramount importance because it is recognized that these injuries are likely to be 44 frequently missed and that left untreated can result in significant increases in tibiofemoral 45 compartment pressures and early arthritis. The recognized rate of missed diagnoses is due 46 to a lack of reliability of pre-operative ...

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

“…This could be due to the fact that 93% of our patients were recreational or competitive athletes, and our patients were younger on average than other studies. 3,18,20 The mechanism for these posterior horn lateral meniscal tears is likely the pivot-shift phenomenon, where subluxation in the lateral compartment of the lateral femoral condyle compresses a The number of tears is larger than number of patients with tear because some patients had bilateral tears or multiple tears on 1 meniscus. the posterior horn of the lateral meniscus.…”

“…2,7,12,13,17,24 Studies have reported the incidence of meniscal tears associated with ACL tears to range between 47% and 65%. 1,7,9,14,18,19 Unlike medial meniscal tears, which commonly occur chronically after ACL injury, lateral meniscal tears occur most commonly with acute ACL injuries. 4,5,7,8 Posterior meniscal tears commonly occur concurrently with ACL injuries.…”

Alternative Techniques for Lateral and Medial Posterior Root Meniscus Repair Without Special Instruments

“…Few publications have evaluated the kinematic and biomechanical effects of a PLMRT compared to a PMMRT 13 ; however, interest in this subject is increasing. A recent study 21 evaluating 3956 patients undergoing ACL reconstruction performed an epidemiological analysis of PLMRTs, which were identified in 6.6% of the cases. In addition, multivariate analysis showed that participation in contact sports and associated medial meniscus tears are independent risk factors for PLMRTs.…”

Arthroscopic Repair of Double Radial Tears of the Lateral Meniscus

“…It is estimated that radial tears or avulsions at the posterior LM root are found in up to 7% to 12% of patients with ACL tears 2, 3. These tears present unique surgical challenges with particular biomechanical consequences 4 .…”

“…LM root tears are likely underrecognized because they are easily missed in preoperative magnetic resonance imaging (MRI) scans 5 . It is critical to have a high suspicion of tears in the setting of ACL injury, particularly in patients with greater tibia varus angles, increased tibial slopes, higher body mass index, contact injuries, and concomitant medial meniscus tears 3, 6. Although uncommon, it is possible to have coexisting radial tears of the posterior horn or root and of the body of the LM secondary to a combined ACL-MCL injury.…”