Meniscal ramp lesions: a lot is known, but a lot is also unknown…

Editorial Commentary: Medial Meniscal Ramp Tears Require Comprehensive Evaluation and Treatment

Various classifications have been proposed for medial meniscal ramp tears, but none have been subjected to validation, reliability, or outcome analysis. A medial meniscal ramp tear is a peripheral detachment of the posterior horn of the meniscus due to either a tear of the meniscocapsular junction or the meniscotibial ligament, or both. Ramp tears are commonly found in association with anterior cruciate ligament rupture. The fascial expansion of the semimembranosus tendon is attached to the posterior horn of the medial meniscus; excessive anterior translation of the tibia stimulates the semimembranosus to contract, resulting in a ramp tear. Risk factors include deep and superficial medial collateral ligament injuries, steep medial tibial slope, flatter lateral tibial slope, varus alignment greater than 3°, posteromedial tibial bone contusion on magnetic resonance imaging (MRI), Segond fracture, and a chronic injury (3 months or more from injury). Untreated ramp lesions are associated with increased anterior knee laxity, which may increase the risk of anterior cruciate ligament graft failure. Diagnosis of a ramp tear is not always straightforward. MRI has only moderate sensitivity because the posterior capsule tightens in extension, reducing meniscocapsular separation. High-resolution MRI with the knee in flexion can improve accuracy. Nevertheless, the gold standard for diagnosis is arthroscopy. Unstable tears should be repaired, and as the meniscocapsular junction has good vascularity, some stable tears may heal after abrasion or trephination. A good classification system should characterize a problem, determine the best treatment, and predict the outcome. Classification systems also aid the consistent reporting and comparison of clinical data.

Effect of Ramp Lesions on Outcomes After Anterior Cruciate Ligament Reconstruction

Background

Ramp lesions (RLs) associated with anterior cruciate ligament (ACL) injury increase knee instability. However, whether RLs should be treated surgically remains unclear.

Purpose/Hypothesis

This study aimed to investigate the presence of RLs and compare the knee stability between patients who underwent surgical repair for unstable RLs and those who received nonoperative management for stable RLs. It was hypothesized that there would be a correlation between RLs and knee instability and that RL repair would improve postoperative knee stability.

Study Design

Cohort study; Level of evidence, 3.

Methods

Overall, 180 patients who underwent primary ACL reconstruction using hamstring tendon graft were included in this study. The decision to perform surgical intervention for RLs was based on the size and instability of the RL. Knee stability was evaluated using the KT-1000 arthrometer for side-to-side difference at the manual maximum, as well as the Lachman and pivot-shift tests. Linear and logistic regression analyses were employed to examine factors associated with knee instability.

Results

Arthroscopy confirmed RLs in 59 patients (32.8%), with a higher prevalence among women; of this total, 33 patients (55.9%) were treated nonoperatively and 26 (44.1%) underwent repair. Although the preoperative side-to-side difference in laxity in the patients with RL was significantly greater than that in patients without RL (P = .01), no significant clinical differences were observed for the preoperative Lachman test (P = .50) and pivot-shift test (P = .36). No secondary meniscal injuries occurred during the follow-up period. There were no significant differences in postoperative laxity between patients with and without RLs.

Conclusion

Although the presence of RLs was associated with preoperative knee instability, contrary to the hypothesis, RLs were not associated with postoperative knee instability. Stable RLs are clinically benign lesions that may tend to heal spontaneously after appropriate anatomic ACL reconstruction. Therefore, RLs may not require aggressive treatment if they are small and stable.

Ramp lesions of the medial meniscus are associated with greater preoperative anterior knee laxity in anterior cruciate ligament injury

PURPOSE

To assess the incidence of ramp lesions in anterior cruciate ligament (ACL) injuries and to compare preoperative knee laxity between the patients with and without ramp lesions by using an electromagnetic measurement system (EMS).

METHODS

Two hundred six patients who underwent primary ACL reconstruction with preoperative EMS measurements were retrospectively enrolled in the present study. The diagnoses of the ramp lesions were made by arthroscopic inspections. The patients with ramp lesions and no other meniscal lesions were allocated to 'ramp group', and the patients without any meniscal lesions were allocated to 'control group'. Before ACL reconstruction under general anaesthesia, the side-to-side difference (SSD) in anterior tibial translation (ATT) during Lachman test (mm) and tibial acceleration (m/s2) of posterior tibial reduction during the pivot-shift test was measured using the EMS. The SSD in tibial internal/external rotation angle (°) at 30, 60 and 90 were further measured using the EMS. The SSD in ATT using KT-2000 was also measured. Knee laxity measurements were compared between two groups using unpaired Student's t test.

RESULTS

Ramp lesions were observed in 30 patients (14.7%). Subsequently, 17 patients were allocated to 'ramp group' and 77 patients to 'control group', and there were no statistical differences with regard to background demographics. ATT-SSD during Lachman test was significantly greater in 'ramp group' (9.1 [95% confidence interval, CI: 5.7-12.5] mm vs. 6.2 [95% CI: 5.1-7.3] mm, p = 0.037). However, SSD in ATT with KT-2000, tibial acceleration during pivot-shift test, and SSD in tibial rotational angles were not significantly different between the two groups.

CONCLUSION

Presence of ramp lesion was associated with increased anterior knee laxity during Lachman test, suggesting ramp lesions may need to be addressed at the time of ACL reconstruction.

LEVEL OF EVIDENCE

IV.

High prevalence of associated injuries in anterior cruciate ligament tears: A detailed magnetic resonance imaging analysis of 254 patients

OBJECTIVES

To evaluate the type and prevalence of associated injuries by using magnetic resonance imaging (MRI) in patients with anterior cruciate ligament (ACL) tears.

METHODS

Data from the Natural Corollaries and Recovery after ACL injury multicenter longitudinal cohort study were analyzed. Between May 2016 and October 2018, patients aged between 15 and 40 years, who had experienced an ACL tear within the last 6 weeks and sought medical attention at one of seven healthcare clinics in Sweden, were invited to participate. The mean time from injury to MRI was 19.6 ± 15.2 days. An orthopedic knee surgeon and a musculoskeletal radiologist reviewed all the MRI scans. The following structures were assessed: posterior cruciate ligament (PCL), medial collateral ligament (MCL) complex, lateral collateral ligament (LCL), popliteus tendon, medial meniscus (MM), lateral meniscus (LM), and cartilage. In addition, the presence of bone bruising, impaction fractures in the lateral femoral condyle (LFC) or posterolateral tibia (PLT), and Segond fractures were also assessed.  RESULTS: A total of 254 patients (48.4% males) with a mean age of 25.4 ± 7.1 years were included. The prevalence of associated injuries was as follows: PCL (0.4%), MCL {41.3% [superficial MCL and deep MCL (dMCL) 16.5%; isolated dMCL 24.8%]}, LCL (2.4%), MM (57.4%), LM (25.2%), cartilage (15.0%), bone bruising (92.9%), impaction fracture in the LFC (45.7%) and PLT (4.7%), and Segond fracture (7.5%).

CONCLUSIONS

The prevalence of associated injuries in patients with ACL tears was high. The findings reported in this study may serve as a reference tool for orthopedic surgeons and radiologists in the diagnosis of associated injuries using MRI in patients with ACL tears.

Approaching ramp lesions from the different world of posterior knee compartment: A review of evidence with a proposal of a new classification and treatment

Ramp lesions (RLs) are peripheral lesions that occur in the posterior part of the medial meniscus or where it attaches to the joint capsule. The classification of the medial meniscus RLs has been the focus of numerous studies and publications. This review provides an overview of RL's current classification and treatment options in anterior cruciate ligament deficient knees. The study also aims to present a more practical classification system for RLs to assist in treatment decision-making. For the first time, we also presented a new surgical treatment for incomplete inferior and double-complete RL based on the posterior knee arthroscopy that provides direct access to the posterior meniscal borders, enabling effective treatment and stronger biomechanical repair.

Level of Evidence

Level V.

Identifying unstable ramp lesions using ultrasonography

BACKGROUND

Patients with suspected ramp lesions on magnetic resonance imaging (MRI) or ultrasonography (US) healed and showed no instability based on intraoperative arthroscopic findings. The purpose of this study was to assess the use of US in evaluating ramp lesions preoperatively and intraoperatively.

METHODS

Eighty-two knees that underwent anterior cruciate ligament (ACL) reconstruction between January 2022 and June 2023 were included to assess the ramp lesion complication rate and instability using arthroscopic findings. The detection rate of ramp lesions using US at the initial visit and preoperatively was also investigated. The test-retest reliability was assessed using the intraclass correlation coefficient and analyzed using two-way random effects and absolute agreement. The patients were divided into two groups based on the presence or absence of ramp lesions, and these data were compared using Student's t-test. Statistical significance was set at p < 0.05.

RESULTS

On ultrasound examination, 90.0% of the cases had a ramp lesion at the initial examination, of which 22.2% were poorly delineated on the day of surgery. In the cases where the ramp lesion was unstable at the time of surgery, it could be delineated using US. In the cases where the ramp lesion was stable, it was difficult to delineate the lesion using US.

CONCLUSIONS

Unstable ramp lesions complicating ACL injuries could be detected using US.

Secondary Meniscectomy Rates and Risk Factors for Failed Repair of Ramp Lesions Performed at the Time of Primary ACL Reconstruction: An Analysis of 1037 Patients From the SANTI Study Group

BACKGROUND

Studies evaluating secondary meniscectomy rates and risk factors for failure of ramp repair are sparse and limited by small numbers and heterogeneity.

PURPOSES/HYPOTHESIS

The purposes were to determine the secondary meniscectomy rate for failure of ramp repair performed using a posteromedial portal suture hook at the time of anterior cruciate ligament reconstruction (ACLR) and to identify risk factors for secondary meniscectomy. It was hypothesized that patients who underwent ACLR combined with a lateral extra-articular procedure (LEAP) would experience significantly lower rates of secondary meniscectomy compared with those undergoing isolated ACLR.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Patients undergoing primary ACLR and ramp repair between 2013 and 2020 were included in the study. Final follow-up for each patient was defined by his or her last appointment recorded in a prospective database (with a study end date of March 2023). The database and medical records were used to determine whether patients had undergone secondary meniscectomy for failure of ramp repair. Survivorship of ramp repair (using secondary meniscectomy as an endpoint) was determined using the Kaplan-Meier method. Multivariate analysis was used to investigate possible risk factors.

RESULTS

A total of 1037 patients were included in the study. The secondary meniscectomy rate after ramp repair was 7.7% at a mean final follow-up of 72.4 months. Patients without combined ACLR + LEAP were >2-fold more likely to undergo a secondary medial meniscectomy compared with those with combined ACLR + LEAP (hazard ratio, 2.455; 95% CI, 1.457-4.135; P = .0007). Age, sex, preoperative Tegner score, and time between injury and surgery were not significant risk factors for failure.

CONCLUSION

The rate of secondary meniscectomy after ramp repair performed through a posteromedial portal at the time of primary ACLR was low. Patients who underwent isolated ACLR (rather than ACLR + LEAP) were >2-fold more likely to undergo a secondary medial meniscectomy for failure of ramp repair. Additional risk factors for failure of ramp repair were not identified.

Effects of an untreated medial meniscal ramp lesion on histological deterioration findings of the medial meniscus: A study in a porcine anterior cruciate ligament reconstruction model

Purpose

To evaluate the effect of untreated medial meniscal ramp lesions (MMRLs) on the tendon graft after anterior cruciate ligament (ACL) reconstruction and histological findings of medial meniscus (MM) in a porcine a model.

Methods

A total of 17 pigs were divided into two groups: (1) the untreated MMRL group (UM group, n = 9) and (2) intact MM group (n = 8) and euthanized 12 weeks after surgery. The specimens were then tested cyclically and loaded to failure. Side-to-side differences (SSDs) in translation under cyclic loading and structural properties were analyzed. Histological evaluation of the MM was also performed.

Results

No significant differences in the SSD in translation during the cyclic testing (UM group, 0.3 ± 0.4 mm; intact MM group, 0.1 ± 1.4 mm), upper yield load (UM group, 476.3 ± 399.9 N; intact MM group, 643.2 ± 302.9 N), maximum load (UM group, 539.5 ± 265.8 N; intact MM group, 705.8 ± 282.6 N), linear stiffness (UM group, 63.5 ± 39.0 N/mm; intact MM group, 73.7 ± 60.1 N/mm) and elongation at failure (UM group, -4.6 ± 16.3 mm; intact MM group, 2.3 ± 6.6 mm) were observed. However, the UM group had significantly worse Modified Mankin's histological grading scores (1.8 ± 0.4 [1-2] vs. 0 ± 0 [0]; p < 0.001) and Modified Copenhaver classification scores (6.6 ± 2.4 [2-9] vs. 0.7 ± 1.1 [0-3]; p < 0.001) than did the intact MM group.

Conclusion

Untreated MMRLs showed postoperative histological deterioration.

Level of Evidence

Level IV.

Risk factors and prevalence of ramp lesions in ACL ruptures: An analysis from the registry of the Francophone Arthroscopic Society

PURPOSE

The study aimed to estimate the prevalence of ramp lesions among patients undergoing anterior cruciate ligament (ACL) reconstruction and identify risk factors associated with these lesions.

METHODS

A retrospective, multicentre cohort study was conducted using data from the Francophone Arthroscopic Society's registry, including 5359 patients who underwent ACL reconstruction (ACLR) from June 2020 to June 2023. Potential risk factors for ramp lesion such as patient demographics, revision surgery, pivot shift, side-to-side anteroposterior laxity, medial collateral ligament (MCL) injury, lateral meniscal tear and the volume of ligament remnant were evaluated using multivariate regression analyses. BMI and delay to surgery were also assessed.

RESULTS

Ramp lesions were identified in 822 patients (15.3%). Univariate analysis identified male sex, younger age, revision surgery, lateral meniscal injury, percentage of ACL remnant (all p < 0.0001) and pivot shift (p = 0.0103) as significant risk factors. MCL injury was associated with a lower risk (p < 0.0001). In multivariate analysis, male sex, younger age, revision surgery, lateral meniscal injury and percentage of ACL remnants remained significant risk factors, while MCL injury remained a protective factor. The anteroposterior laxity wasn't a significant predictor in either analysis. In subgroup analysis, there were no differences concerning body mass index (n.s) and the delay to surgery (n.s).

CONCLUSION

The study identified male sex, younger age, revision surgery, lateral meniscal injury and pourcentage of ACL remnant as significant risk factors for ramp lesions, with MCL injury acting as a protective factor. This will help regarding the suspicion and identification of ramp lesions.

LEVEL OF EVIDENCE

Level III.

Increased Intra-Articular Internal Tibial Rotation Is Associated With Unstable Medial Meniscus Ramp Lesions in ACL-Injured Athletes: An MRI Matched-Pair Comparative Study

Purpose

To analyze internal tibial rotation through magnetic resonance imaging (MRI) of patients with anterior cruciate ligament (ACL) injuries with and without an unstable medial meniscal ramp lesion (MMRL).

Methods

Retrospective analysis of prospectively data was performed to include all consecutive patients who underwent primary ACL reconstruction (ACLR) between January 2022 and June 2022. Two groups, ACLR + unstable MMRL and ACLR without MMRL, were constituted. Propensity score matching analysis was used to limit selection bias. The angle between surgical epicondylar axes (SEAs) and the tangent line of the posterior tibial condyles (PTCs) was measured to analyze the rotational alignment between distal femur and proximal tibia. MMRLs were defined unstable if they were ≥1 cm, if the lesions extend beyond the lower pole of the femoral condyle, and/or if there was displacement into the medial compartment by anterior probing.

Results

Twenty-eight propensity-matched pairs were included. The ACLR + unstable MMRL presented a significantly greater internal rotation of the tibia compared to ACLR without MMRL (P < .001). An internal tibial rotation was associated with unstable ramp lesions in ACL-injured patients (odds ratio [OR], 0.36; 95% CI, 0.25-0.41; P < .0001). If SEA-PTC was 0°, the sensitivity and specificity of the SEA-PTC angle to detect unstable MMRL were respectively 100% (95% CI, 85%-100%) and 18% (95% CI, 8%-36%). Otherwise, if SEA-PTC angle was -10°, the sensitivity and specificity of the SEA-PTC angle to detect unstable MMRL were respectively 43% (95% CI, 27%-61%) and 96% (95% CI, 81%-100%). Bone edema of the posterior medial tibial plateau was significantly associated with unstable ramp lesions (OR, 1.58; 95% CI, 1.21-2.06; P = .029).

Conclusions

Unstable MMRL concomitant to an ACL rupture was associated with an increased tibial internal rotation.

Level of Evidence

Level III, retrospective comparative trial.

Influence of a posteromedial meniscocapsular injury on the knee anterior laxity. A cadaveric study

PURPOSE

The number of anterior cruciate ligament (ACL) injuries has considerably increased in the recent years, especially in young adults and adolescents. Associated meniscal tears increase anterior and rotary laxity. Posterior peripheral meniscocapsular tear of medial meniscus is also called ramp lesion. Prevalence of 9% to 17% in adults and up to 23% in pediatric population has been reported. The aim of this study was to determine anterior laxity of cadaveric ACL-deficient knees with several size of ramp lesions.

METHODS

Fresh cadaveric knees were explored. Major osteoarthritis and/or ACL and meniscal tears on arthroscopy were exclusion criteria. Mean age at death was 86 years old. Dynamic laximetry with GNRB® device was made in several conditions: Knee prior to any procedure, after arthroscopic exploration, after ACL section, and then after increasing sizes of ramp lesions up to 30 mm. Anteroposterior laxity was measured with 2 loading forces successively (134N and 200N).

RESULTS

After ACL section only, tibiofemoral joint anterior laxity was significantly increased. Mean increase was 156% regardless of the loading force. No statistical laxity difference was found between knees with ACL section only and knees with ACL and meniscal section for any size of ramp lesions. Increasing size of ramp lesion was not correlated with increasing of laxity.

CONCLUSION

We could not find a threshold size of ramp lesion which increases knee anterior laxity. We were not able to determine a threshold recommending a ramp lesion repair.