Editorial Commentary: Medial Meniscal Ramp Lesions: Lessons Learned From the Past in the Pursuit of Evidence

Posterior Cruciate Buckling Angle Variations Are Associated with Different Patterns of Medial Meniscus Tears in Anterior-Cruciate-Deficient Knees: Results of a Prospective Comparative Magnetic Imaging Resonance Study

BACKGROUND

The diagnosis of anterior cruciate ligament (ACL) tear relies on clinical evaluation and magnetic resonance imaging (MRI). Direct and indirect signs of ACL tear have been described with MRI evaluation. Posterior cruciate ligament (PCL) buckling has been described as an indirect radiographic sign of an ACL tear.

PURPOSE

The aim of the present study was to assess the variations in PCL buckling angles in patients with ACL tears and in patients with isolated lesions in the posterior horn of the medial meniscus. In addition, the influence of different patterns of medial meniscus tears in ACL-deficient knees was investigated. Finally, the influences of risk factors such as tibial slope, delay from injury to surgery, absence of medial meniscus tear, degree of Lachman and pivot shift testing were also assessed.

STUDY DESIGN

This was a cohort study.

METHODS

A total of 154 patients (78 in the group with ACL tear and 76 in the control group) were assessed with MRI and lateral weight-bearing X-ray to assess PCL buckling angle and tibial slope by two independent observers. The presence of a medial meniscus bucket handle or ramp lesion of the medial meniscus was assessed and recorded at the time of surgery.

RESULTS

PCL buckling angle measurement was highly reliable, with an ICC of 0.866 and 0.894, respectively, in the study group and the control group for interobserver reliability. The intrarater reliability was found to be high in PCL buckling angle for the study group [ICC = 0.955] and the control group [ICC = 0.943]. The mean angle in patients with ACL tear was 110.7 ± 15.2° and 115.3 ± 16.2° (for the two examiners) and 111.4 ± 12° and 114 ± 14.5° (for the two examiners) in patients with an intact, healthy ACL. An association emerged between bucket handle tears of the medial meniscus (p = 0.010) and a decreased PCL buckling angle and between ramp lesions of the medial meniscus and increased PCL buckling angle both (p = 0.024).

CONCLUSIONS

Good inter- and intraobserver reliability for the measurement of the PCL buckling angle was observed. Increased PCL buckling angle values were observed in patients with concomitant ACL and bucket handle tears of the medial meniscus, while decreased angle values were observed in those who had ACL tear and ramp lesion of the medial meniscus. No statistically significant difference in the PCL buckling angle emerged between patients with ACL tears and those who had a healthy, intact ACL.

Management of Anterior Cruciate Ligament Tears in Skeletally Immature Patients

PURPOSE OF REVIEW

Anterior cruciate ligament (ALC) tears are increasingly common in skeletally immature patients, as more children and adolescents participate in intensive sports training and specialization at increasingly younger ages. These injuries were historically treated nonoperatively, given concerns for physeal damage and subsequent growth disturbances after traditional ACL reconstruction techniques. However, there is now sufficient data to suggest superior outcomes with operative treatment, specifically with physeal-sparing and physeal-respecting techniques. This article reviews considerations of skeletal maturity in patients with ACL tears, then discusses surgical techniques, with a focus on their unique indications and outcomes. Additional surgical adjuncts and components of postoperative rehabilitation, which may reduce retear rates, are also considered.

RECENT FINDINGS

Current research shows favorable patient-reported outcomes and high return-to-sport rates after ACL reconstruction in skeletally immature patients. Graft rupture (ACL retear) rates are low, but notably higher than in most adult populations. Historically, there has been insufficient research to comprehensively compare reconstruction techniques used in this patient population. However, thoughtful systematic reviews and multicenter prospective studies are emerging to address this deficit. Also, more recent data suggests the addition of lateral extra-articular procedures and stringent return-to-sports testing may lower retear rates. Physeal-sparing and physeal-respecting ACL reconstructions result in stabilization of the knee, while respecting the growth remaining in children or skeletally immature adolescents. Future research will be essential to compare these techniques, given that more than one may be appropriate for patients of a specific age and skeletal maturity.

Extrusion and meniscal mobility evaluation in case of ramp lesion injury: a biomechanical feasibility study by 7T magnetic resonance imaging and digital volume correlation

Introduction: The existing body of literature on the biomechanical implications of ramp lesions is limited, leaving a significant gap in our understanding of how these lesions impact joint kinematics and loading in the medial compartment. This cadaveric biomechanical study aims to address this gap by employing an innovative Digital Volume Correlation (DVC) method, utilizing 7 Tesla Magnetic Resonance Imaging (MRI) images under various loading conditions. The primary objective is to conduct a comprehensive comparison of medial meniscal mobility between native knees and knees affected by grade 4 ramp lesions. By focusing on the intricate dynamics of meniscal mobility and extrusion, this work seeks to contribute valuable insights into the biomechanical consequences of medial meniscus ramp lesions. Materials and methods: An initial set of 7T MRI imaging sessions was conducted on two intact native knees, applying load values up to 1500N. Subsequently, a second series of images was captured on these identical knees, with the same loads applied, following the creation through arthroscopy of medial meniscus ramp lesions. The application of DVC enabled the precise determination of the three components of displacement and spatial variations in the medial menisci, both with and without ramp lesions. Results: The measured directional displacements between native knees and injured knees indicate that, following the application of axial compression load, menisci exhibit increased extrusion and posterior mobility as observed through DVC. Discussion: Injuries associated with Subtype 4 medial meniscus ramp lesions appear to elevate meniscal extrusion and posterior mobility during axial compression in the anterior cruciate ligament of intact knees. Following these preliminary results, we plan to expand our experimental approach to encompass individuals undergoing weight-bearing MRI. This expansion aims to identify meniscocapsular and/or meniscotibial insufficiency or rupture in patients, enabling us to proactively reduce the risk of osteoarthritic progression.

Medial meniscal ramp lesions in ACL-injured elite athletes are strongly associated with medial collateral ligament injuries and medial tibial bone bruising on MRI

PURPOSE

Medial menisco-capsular separations (ramp lesions) are typically found in association with anterior cruciate ligament (ACL) deficiency. They are frequently missed preoperatively due to low MRI sensitivity. The purpose of this article was to describe demographic and anatomical risk factors for ramp lesions, and to identify concomitant lesions and define their characteristics to improve diagnosis of ramp lesions on MRI.

METHODS

Patients who underwent anterior cruciate ligament (ACL) reconstruction between September 2015 and April 2019 were included in this study. The presence/absence of ramp lesions was recorded in preoperative MRIs and at surgery. Patients' characteristics and clinical findings, concomitant injuries on MRI and the posterior tibial slope were evaluated.

RESULTS

One hundred patients (80 male, 20 female) with a mean age of 22.3 ± 4.9 years met the inclusion criteria. The incidence of ramp lesions diagnosed at surgery was 16%. Ramp lesions were strongly associated with injuries to the deep MCL (dMCL, p < 0.01), the superficial medial collateral ligament (sMCL, p < 0.01), and a small medial-lateral tibial slope asymmetry (p < 0.05). There was also good correlation between ramp lesions and bone oedema in the posterior medial tibia plateau (MTP, p < 0.05) and medial femoral condyle (MFC, p < 0.05). A dMCL injury, a smaller differential medial-lateral tibial slope than usual, and the identification of a ramp lesion on MRI increases the likelihood of finding a ramp lesion at surgery. MRI sensitivity was 62.5% and the specificity was 84.5%.

CONCLUSION

The presence on MRI of sMCL and/or dMCL lesions, bone oedema in the posterior MTP and MFC, and a smaller differential medial-lateral tibial slope than usual are highly associated with ramp lesions visible on MRI. Additionally, a dMCL injury, a flatter lateral tibial slope than usual, and the identification of a ramp lesion on MRI increases the likelihood of finding a ramp lesion at surgery. Knowledge of the risk factors and secondary injury signs associated with ramp lesions facilitate the diagnosis of a ramp lesion preoperatively and should raise surgeons' suspicion of this important lesion.

LEVEL OF EVIDENCE

Diagnostic study, Level III.

Epidemiological Evaluation of Meniscal Ramp Lesions in 3214 Anterior Cruciate Ligament-Injured Knees From the SANTI Study Group Database: A Risk Factor Analysis and Study of Secondary Meniscectomy Rates Following 769 Ramp Repairs

BACKGROUND

Ramp lesions are characterized by disruption of the peripheral meniscocapsular attachments of the posterior horn of the medial meniscus. Ramp repair performed at the time of anterior cruciate ligament reconstruction (ACLR) has been shown to improve knee biomechanics.

PURPOSE

The primary objectives of this study were to evaluate the incidence of and risk factors for ramp lesions among a large series of patients undergoing ACLR. Secondary objectives were to determine the reoperation rate for failure of ramp repair, defined by subsequent reoperations for partial medial meniscectomy.

STUDY DESIGN

Case-control study; Level of evidence, 3. Case series; Level of evidence, 4.

METHODS

All patients underwent transnotch posteromedial compartment evaluation of the knee during ACLR. Ramp repair was performed if a lesion was detected. Potentially important risk factors were analyzed for their association with ramp lesions. A secondary analysis of all patients who underwent ramp repair and had a minimum follow-up of 2 years was undertaken to determine the secondary partial meniscectomy rate for failed ramp repair.

RESULTS

The overall incidence of ramp lesions in the study population was 23.9% (769 ramp lesions among 3214 patients). Multivariate analysis demonstrated that the presence of ramp lesions was significantly associated with the following risk factors: male sex, patients aged <30 years, revision ACLR, chronic injuries, preoperative side-to-side laxity >6 mm, and concomitant lateral meniscal tears. The secondary meniscectomy rate was 10.8% at a mean follow-up of 45.6 months (range, 24.2-66.2 months). Patients who underwent ACLR + anterolateral ligament reconstruction had a >2-fold reduction in the risk of reoperation for failure of ramp repair as compared with patients who underwent isolated ACLR (hazard ratio, 0.457; 95% CI, 0.226-0.864; P = .021).

CONCLUSION

There is a high incidence of ramp lesions among patients undergoing ACLR. The identification of important risk factors for ramp lesions should help raise an appropriate index of suspicion and prompt posteromedial compartment evaluation. The overall secondary partial meniscectomy rate after ramp repair is 10.8%. Anterolateral ligament reconstruction appears to confer a protective effect on the ramp repair performed at the time of ACLR and results in a significant reduction in secondary meniscectomy rates.