Page 24 - 2020 ISAKOS Newsletter Volume I

CURRENT CONCEPTS
Is It Necessary to Repair Meniscal Ramp Lesions?
The name “ramp” derives from the arthroscopic appearance of a downward “ramp” when viewing the meniscocapsular junction posteromedially. The importance of these lesions stems from their relationship with the anterior cruciate ligament (ACL), and the reported prevalence of these lesions at the time of ACL reconstruction (ACLR) has ranged from 16% to 24%. Biomechanical studies have demonstrated that unaddressed meniscal ramp lesions increase anterior tibial translation and internal rotation in the ACL-deficient knee and place extra stress on the ACLR graft.1,2 However, because of a lack of clinical outcomes studies, controversy remains with regard to whether or not it is necessary to repair all of these lesions at the time of ACLR. The purpose of this report is to review the biomechanical literature on meniscal ramp lesions and to describe our preferred repair technique.
Biomechanical Consequences
The medial meniscus has been reported to have an essential role in stabilizing knees with chronic ACL deficiency. Biomechanical studies have demonstrated the interdependence between the medial meniscus and the ACL, specifically with regard to the role of the posterior horn of the medial meniscus (PHMM) as a secondary stabilizer to anterior tibial translation (ATT). Muriuki et al. described changes in tibiofemoral contact pressures after vertical tears of the PHMM as compared with those after radial split tears. The authors concluded that vertical tears of the PHMM increased contact pressure and reduced contact area in the medial and lateral compartments, similar to the findings after total medial meniscectomy. In 2001, Papageorgiou et al. demonstrated the biomechanical interdependence between the ACLR graft and the medial meniscus. The authors reported as much as a 54% increase in force in the ACLR graft after medial meniscectomy, further demonstrating the potential for increased ACLR graft failure in association with medial meniscal deficiency. Recent data have suggested that medial meniscal ramp tears, when left untreated, may predispose the ACL-reconstructed knee to increased ATT and potentially increased strain in the ACLR graft, correlating with graft failure.2,3
The biomechanical functions of the PHMM attachments are essential, with recent investigations demonstrating that meniscal deficiency is the most significant clinical factor predicting ACLR graft failure. In 2018, DePhillipo et al. reported significant increases in ATT at 30° and 90° in ACL- deficient knees in association with the presence of both meniscocapsular and meniscotibial ramp lesions.1 They also reported significant increases in internal and external rotation and pivot shift in knees with ramp lesions and found that restoration was not achieved with an isolated ACLR but was achieved with a combined ACLR and meniscal ramp repair. Furthermore, these biomechanical consequences of ramp tears have been corroborated by other biomechanical studies.2-5
Abstract
Nicholas N. DePhillipo, MS,
ATC, OTC
Twin Cities Orthopedics, Edina, MN Oslo Sports Trauma Research Center, Oslo, NORWAY
Lars Engebretsen MD, PhD
Oslo Sports Trauma Research Center, Oslo, NORWAY
Robert F. LaPrade, MD, PhD
Twin Cities Orthopedics, Edina, MN UNITED STATES
Meniscal ramp lesions are commonly associated with ACL tears and are becoming more frequently recognized both preoperatively and intraoperatively. Despite the renewed research interest surrounding this meniscal tear pattern in the past decade, the majority of literature focuses on diagnosis and biomechanical consequences and lacks clinical validation. As a result, the biomechanical evidence has been questioned by clinicians as to whether or not the increased knee kinematics associated with untreated ramp lesions are clinically relevant. This controversy has called into question the necessity of surgical repair of ramp lesions that are identified at the time of ACL reconstruction. Nonetheless, the biomechanical evidence presented by multiple groups has consistently identified increased knee translation and the potential for increased stress within the ACL reconstruction graft if left untreated.
Introduction
In recent years, increased attention has been directed toward the identification and treatment of medial meniscal ramp lesions. Much of the previous literature has focused on improving the diagnosis of ramp lesions because of their potential “hidden” location, with tears lying at the posteromedial capsular meniscal attachment.
22 ISAKOS NEWSLETTER 2020: VOLUME I