Diagnostic Performance of Magnetic Resonance Imaging for Detecting Meniscal Ramp Lesions in Patients With Anterior Cruciate Ligament Tears: A Systematic Review and Meta-analysis

Improving tissue contrast visualization in two-point Dixon MRI using dark-fat processing: application in clinical knee imaging

OBJECTIVE

To improve tissue contrast visualization in water-only images from two-point turbo spin-echo (TSE) Dixon MRI using dark-fat image processing and evaluate in retrospectively acquired clinical knee images.

MATERIALS AND METHODS

Clinical knee MRI datasets from 36 patients were retrospectively compiled under IRB approval. The dark-fat water-only images were generated and compared with the conventional water-only images from two-point TSE-Dixon MRI. The water-only images from 20 patients were analyzed: (i) qualitatively by two experienced musculoskeletal radiologists, for overall image quality, fat suppression, anatomical visualization, and the absence of artifacts, using Wilcoxon rank tests, and (ii) quantitatively using apparent signal-to-noise ratio (aSNR) and apparent contrast-to-noise ratio (aCNR) from regions of interest (ROIs) with paired t-test. In the remaining 16 patients, the number of cruciate ligament tears identified on MRI was tabulated and compared with arthroscopy results.

RESULTS

Compared to conventional water-only images, dark-fat water-only images showed improved fat suppression (reader 1, P < 0.0001; reader 2, P < 0.05), improved overall image quality by reader 1 (P < 0.001), and improved visualization of the sciatic nerve for reader 1 (P < 0.01), while there were no significant differences for the other anatomical structures. aSNR was significantly reduced for bone marrow fat (P < 0.0001), and aCNR between meniscus and articular cartilage was significantly improved (P < 0.0001). There were a higher number of posterior cruciate ligament tears identified in MRI compared to arthroscopy.

CONCLUSION

Dark-fat processed water-only images improved fat suppression and tissue contrast visualization, particularly sciatic nerves, compared to conventional water-only images from two-point TSE-Dixon MR imaging.

Prevalence and Risk Factors for Medial Meniscus Ramp Lesions in the Setting of Pediatric Anterior Cruciate Ligament Injuries: A Systematic Review and Meta-analysis

BACKGROUND

Medial meniscus ramp lesions (MMRLs) are commonly associated with anterior cruciate ligament (ACL) injuries and may increase the risk of graft failure after ACL reconstruction (ACLR) if undiagnosed or left untreated. Although MMRLs have been extensively reported in adults, there are limited studies describing them in pediatric patients undergoing ACLR. The purpose of this study was to perform a systematic review and meta-analysis to determine the pooled prevalence of and risk factors for MMRLs in pediatric patients with ACL injuries.

METHODS

PubMed, Scopus, and Cochrane Central Register of Controlled Trials (CENTRAL) databases were queried in December 2023 for studies reporting on MMRLs in pediatric patients (≤21 y old) undergoing ACLR. Articles were only included if they reported on the prevalence and/or risk factors for arthroscopically diagnosed MMRLs. DerSimonian-Laird binary random-effects models were constructed to quantitatively evaluate the association between risk factors and MMRLs by generating effect estimates in the form of odds ratios (OR) with 95% CI.

RESULTS

Seven studies were identified, which included 1362 pediatric patients (mean±SD age, 15.3±1.4 y old) that underwent ACLR. The pooled MMRL prevalence was 16.4% (range, 13.2% to 28%) calculated across 6 studies. Of the 7 studies identified, 5 qualified for the risk factor analysis, which included a total of 536 ACLR patients. Twenty risk factors were identified, of which 8 were amenable to being explored quantitatively. Anterolateral ligament (ALL) injuries on magnetic resonance imaging (MRI) [odds ratio (OR), 4.16; 95% CI, 1.40-12.34; P =0.01], MMRLs on preoperative MRI (OR, 4.09; 95% CI, 2.52-6.64; P <0.00010), posteromedial tibial plateau bone marrow edema (OR, 2.11; 95% CI, 1.16-3.83; P =0.01), and concomitant lateral meniscus tears (OR, 1.70; 95% CI, 1.04-2.76; P =0.03) were important risk factors for pediatric MMRLs. Skeletal maturity (physes open or closed), male sex, or collateral ligament injury was not associated with the presence of pediatric MMRLs.

CONCLUSION

The overall pooled prevalence of MMRLs was 16.4% in pediatric patients undergoing ACLR. Significant risk factors for pediatric MMRLs included the presence of concomitant ALL injuries on MRI, identification of MMRLs on MRI, posteromedial tibia plateau bone marrow edema, and concomitant lateral meniscus tears at the time of surgery. Skeletal maturity, male sex, or collateral ligament injury were not associated with MMRLs in pediatric ACL tears.

LEVEL OF EVIDENCE

Systematic review and meta-analysis; level of evidence: IV.

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.

Diagnostic Accuracy of Magnetic Resonance Imaging in the 120° Flexed-Knee Position for Detecting and Classifying Meniscal Ramp Lesion

BACKGROUND

Detection of meniscal ramp lesions concomitant with anterior cruciate ligament (ACL) injury using conventional magnetic resonance imaging (MRI) has low sensitivity, and these lesions are currently difficult to diagnose preoperatively.

PURPOSE/HYPOTHESIS

The purpose of this study was to assess the accuracy of MRI in detecting the presence of meniscal ramp lesions in the 120° flexed-knee position compared with that in the near-extended-knee position. It was hypothesized that the diagnostic performance of MRI in the 120° flexed-knee position would be better than that in the extended-knee position.

STUDY DESIGN

Cohort study (Diagnosis); Level of evidence, 2.

METHODS

This retrospective study of prospectively collected data between February 2019 and January 2024 included 154 consecutive patients undergoing ACL reconstruction. All patients underwent 3-T MRI examination in the near extended- and 120° flexed-knee positions preoperatively. The presence and Thaunat classification of ramp lesions were separately detected on each MRI scan and confirmed via arthroscopy during ACL reconstruction. Diagnostic sensitivity, specificity, and conditional relative odds ratios for detecting ramp lesions and the classification accuracy were compared between 2 MRI modalities. The accuracies of these MRI scans in acute and chronic cases were also evaluated.

RESULTS

This study included 154 patients (79 male and 75 female; mean age, 29.0 ± 14.2 years). A total of 62 ramp lesions (40.3%) were observed on arthroscopy. The sensitivity and specificity of MRI in near extension were 69.4% and 77.2%, respectively, and those in flexion were 91.9% and 94.6%, respectively, with significant superiority in MRI at knee flexion (P = .003 and P < .001, respectively). The conditional relative odds ratio between the MRI examinations at these 2 positions was 10.3 (95% CI, 4.82-21.8). The classification accuracy of MRI in flexion was significantly higher than that of MRI in near extension (accuracy, 49 vs 11; P < .001). The diagnostic accuracy of MRI in the 120° flexed-knee position was significantly higher than that in the near-extended-knee position in the acute cases (P < .05); however, no significant differences were observed in the chronic cases.

CONCLUSION

The diagnostic accuracy of MRI in the 120° flexed-knee position for detecting and classifying meniscal ramp lesions was superior to that of MRI in the near-extended-knee position.

Evaluation of the reliability and accuracy of MRI for the diagnosis of meniscal ramp lesions

BACKGROUND

Meniscal ramp lesions are a special type of meniscal injury that affects the periphery of the posterior horn of the medial meniscus and/or its meniscocapsular attachments, strongly associated with anterior cruciate ligament (ACL) tears. Due to their location, these lesions can be missed arthroscopically so it is essential to diagnose them on preoperative magnetic resonance imaging (MRI).

PURPOSE

To evaluate the accuracy of MRI in detecting meniscal ramp lesions in patients with ACL tears using arthroscopy as the reference standard.

MATERIAL AND METHODS

Two musculoskeletal radiologists, blinded to the surgical findings, retrospectively and independently evaluated 106 knee MRI scans for the presence of meniscal ramp lesions in non-consecutive patients who underwent arthroscopic ACL reconstruction between January 2019 and July 2022 by a single surgeon at one institution. Having arthroscopy as reference, the diagnostic sensitivity and specificity as well as the positive and negative predictive values (PPV/NPV) of the MRI scans were calculated. Cohen's kappa coefficient was used to test inter-observer reliability. A P value <0.05 was considered statistically significant.

RESULTS

In the study group of 106 patients (72 men, 34 women; mean age = 33.84 ±13.12 years), 76 had an arthroscopy-confirmed meniscal ramp lesion, while 30 did not. The sensitivity and specificity of MRI for the detection of meniscal ramp lesion were 88% and 87%, respectively. The PPV and NPV were 94% and 74%, respectively. Inter-rater reliability was excellent (k = 0915).

CONCLUSION

This study demonstrates that MRI can accurately detect meniscal ramp lesions.

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.

The Incidence of Injuries to Ramp Semimembranosus Complex Lesions After ACL Injury: An MRI Study

Background

Medial meniscal ramp lesions have recently been an area of interest because of their recognized prevalence in association with anterior cruciate ligament (ACL) ruptures. Anatomically, the medial meniscal ramp is composed of the meniscocapsular ligament in continuity with the semimembranosus muscle and the meniscotibial ligament. Diagnosis of ramp semimembranosus complex (RSC) injuries remains challenging, and their prevalence is likely to be underestimated in comparison with ramp lesions.

Purpose

To determine the prevalence of RSC lesions after a complete ACL rupture.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

A retrospective database analysis was performed. The cohort consisted of the first 100 patients with complete ACL rupture confirmed by magnetic resonance imaging (MRI) who underwent knee arthroscopy for ACL reconstruction in 2019. The semimembranosus lesions were identified using MRI by 2 independent radiologists specializing in musculoskeletal imaging. The ramp lesions were initially diagnosed using MRI and then confirmed during arthroscopy by an experienced knee surgeon. The magnitude of rotatory instability was recorded using the pivot-shift test. A multivariate analysis was used to determine the lesions associated with the semimembranosus complex.

Results

Of 100 patients, 53 showed lesions of the RSC; among them, 30 ramp lesions were confirmed after arthroscopic evaluation, and 40 semimembranosus lesions (23 without ramp lesion and 17 with ramp lesion) were found using MRI. A positive pivot shift was present in 57% of patients with combined RSC injury (P = .04) compared with 36% in patients without an RSC lesion.

Conclusion

Lesions of the RSC were found in more than half of ACL ruptures in this retrospective cohort. Rotational instability could be associated with combined ACL and RSC injury.

Secondary restraints in ACL reconstruction: State-of-the-art

At-risk patients continue to experience a high likelihood of graft rupture after anterior cruciate ligament (ACL) reconstruction (ACLR). This narrative review seeks to provide the reader with an evidence-based synopsis of state-of-the-art concepts related to secondary restraint lesions, and how addressing them surgically might result in improved outcomes of ACLR.

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.

Meniscal ramp lesion classification systems: A systematic review

PURPOSE

To describe the proposed classification systems for meniscal ramp lesions (RLs) in the literature and evaluate their accuracy and reliability.

METHODS

A systematic search was conducted according to the Preferred Reporting Items for Systematic reviews and Meta-analyses guidelines utilising PubMed, Embase and Cochrane Library databases. Level I-IV studies referencing RLs along with either an arthroscopic- or magnetic resonance imaging (MRI)-based classification system used to describe RL subtypes were included.

RESULTS

In total, 21 clinical studies were included. Twenty-seven (79%) of the included studies were published in 2020 or later. There were four main classification systems proposed within the literature (two arthroscopic-, two MRI-based), describing tear patterns, mediolateral extent, associated ligament disruption and stability of the lesion. The first classification was proposed in 2015 by Thaunat et al. and is referenced in 22 (64.7%) of the included studies. The application of the Thaunat et al. criteria to MRI showed variable sensitivity (31.70%-93.8%) and interobserver agreement (k = 0.55-0.80). The Greif et al. modification to the Thaunat et al. system was referenced in 32.4% of the included studies and had a substantial interobserver agreement (k = 0.8). Stability to probing and specific tear location were each used to classify RLs in 28.6% and 23.8% of the included clinical studies, respectively.

CONCLUSION

Although there has been a recent increase in the recognition and treatment of meniscal RLs, there is limited consistency in descriptive classifications used for this pathology. Current RL classification systems based on preoperative MRI have variable reliability, and arthroscopic examination remains the gold standard for diagnosis and classification.

LEVEL OF EVIDENCE

Level IV.

How to repair medial meniscal ramp lesions: A systematic review of surgical techniques

Purpose

to provide a comprehensive overview of all the surgical techniques published in the literature for repairing meniscal ramp lesions focusing on the technical aspects and the pros and cons of every procedure. Such lesions can be managed using various approaches, each of this with its specific advantages and disadvantages.

Methods

Pubmed Central, Scopus, and EMBASE databases were systematically reviewed according to the preferred reporting items for systematic reviews and meta-analysis (PRISMA) guidelines for studies on surgical techniques for repairing meniscal ramp lesions through May 2023. Overall, 32 articles matched the selection criteria and were included in the study.

Results

Debridement alone may be sufficient for small stable meniscal ramp lesions but, for tears in the menisco-capsular junction that affect the stability of the medial meniscus, it seems reasonable to repair it, even though the clinical results available in literature are contrasting. All-inside sutures through anterior portals seems to be an effective solution for meniscal ramp lesions with MTL tears. All-inside sutures through posteromedial portals are particularly useful for large meniscal ramp lesions, in which an inside-out suture can also be performed.

Conclusion

Meniscal ramp lesions can be managed using various approaches, each of this with its specific advantages and disadvantages. Further research is required to determine the optimal technique that can be considered as the gold standard and can provide the better results.

Level of Evidence

Level III, systematic review.

Evaluating the Diagnostic Performance of MRI for Identification of Meniscal Ramp Lesions in ACL-Deficient Knees: A Systematic Review and Meta-Analysis

BACKGROUND

Despite vigorous efforts to delineate the efficacy of magnetic resonance imaging (MRI) for the diagnosis of meniscal ramp lesions, there is still a great deal of uncertainty regarding its diagnostic performance. Therefore, we conducted a systematic review and meta-analysis to investigate the diagnostic performance of MRI for detecting ramp lesions in anterior cruciate ligament (ACL)-deficient knees.

METHODS

We performed a systematic search of MEDLINE via PubMed, Scopus, Web of Science, and Embase and included all articles, published before October 20, 2022, comparing the accuracy of MRI with that of arthroscopy as the gold standard for diagnosis of ramp lesions. We performed statistical analysis using Stata and Meta-DiSc software. Quality assessment of the included studies was performed using the QUADAS-2 (Quality Assessment of Diagnostic Accuracy Studies-2) tool.

RESULTS

This meta-analysis evaluated 21 diagnostic performance comparisons from 19 original research articles (2,149 patients). The pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and area under the summary receiver operating characteristic (SROC) curve for diagnosing a ramp lesion were 0.70 (95% confidence interval [Cl], 0.66 to 0.73), 0.88 (95% Cl, 0.86 to 0.89), 6.49 (95% Cl, 4.12 to 10.24), 0.36 (95% Cl, 0.28 to 0.46), 24.33 (95% Cl, 12.81 to 46.19), and 0.88, respectively. Meta-regression using different variables yielded the same results.

CONCLUSIONS

MRI exhibited a DOR of 24.33 and moderate sensitivity, specificity, and accuracy for diagnosing ramp lesions in ACL-deficient knees. However, arthroscopy using a standard anterolateral portal with intercondylar viewing is recommended to confirm a diagnosis of a ramp lesion.

LEVEL OF EVIDENCE

Diagnostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Magnetic resonance imaging shows low sensitivity but good specificity in detecting ramp lesions in children and adolescents with ACL injury: A systematic review

IMPORTANCE

The diagnosis of ramp lesions can be problematic, even with arthroscopy, due to their extreme posteromedial position. Consequently, they have been colloquially referred to as the "hidden lesions" of the knee. Undiagnosed and untreated injuries in this knee region may be associated with ongoing dynamic rotational laxity of the knee after anterior cruciate ligament reconstruction and an increased risk of anterior cruciate ligament graft failure.

AIM

This study aimed to systematically review the literature to assess the sensitivity, specificity and accuracy of magnetic resonance imaging (MRI) for detecting ramp lesions in children and adolescents with anterior cruciate ligament (ACL)-deficient knees. It was hypothesized that MRI has poor sensitivity for identifying ramp lesions in children and adolescents.

EVIDENCE REVIEW

A systematic review was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The following search terms were used in the title, abstract and keywords fields: "ramp" or "meniscus" AND "children" or "adolescents." The outcome data extracted from the studies were incidence of ramp in concomitant with ACL lesion, MRI sensitivity, specificity, accuracy and positive and negative predictive values (PPV and NPV).

FINDINGS

Of the 387 patients with ACL injury, 90 were reported to have ramp lesions (23.3%). The mean age at the time of diagnosis was 15.3 ​± ​0.81 years. The mean time from injury to MRI was 116.1 ​± ​113.5 days, while the mean time from injury to surgery was 172.6 ​± ​139.1 days. The MRI taken to detect ramp lesions in the paediatric population showed a pooled sensitivity of 50%, specificity of 75%, accuracy of 70%, PPV of 41% and NPV of 79%.

CONCLUSIONS AND RELEVANCE

The prevalence of ACL-associated ramp lesions in children and adolescents is similar to that in adult populations. Magnetic resonance imaging has low sensitivity but good specificity for assessing ramp lesions. In the presence of a posteromedial tibial bone bruise or a thin fluid signal separating the posterior horn of the medial meniscus and the posteromedial capsule a ramp lesion should always be suspected.

LEVEL OF EVIDENCE

Level IV.

STUDY REGISTRATION

PROSPERO -: CRD42023453895.

[Meniscus update]

Meniscus tears are classified as horizontal, longitudinal, radial, and complex tears. Flap tears are a specific form in which a portion of the meniscus is displaced from a horizontal or longitudinal tear. The question of whether it is possible to preserve the meniscus by meniscus repair is of crucial therapeutic importance. It is therefore important to specify not only the configuration of the tear but also its extent and location as precisely as possible. Cooper's zonal classification should also be used for this purpose. Lesions of the meniscus roots are of high clinical relevance. On the posterior horn of the medial meniscus, root lesions are usually degenerative; on the posterior horn of the lateral meniscus, they are often traumatic. It is important to familiarize oneself with the normal appearance and anatomical location of the meniscal roots. Ramp lesions have received particular attention in recent years, especially in patients with anterior cruciate ligament tears. Therefore, particularly the integrity of the attachment of the posterior horn of the medial meniscus to the tibial plateau must be analyzed. If the meniscotibial ligament tears along its course or at the insertion to the meniscus or if it avulses with a meniscus fragment, this is a ramp lesion.

Editorial Commentary: A Gap-Based Subclassification of Ramp Lesions Has the Potential to Enhance Treatment Precision and Patient Outcomes in Anterior Cruciate Ligament-Deficient Knees Subtitle: Customizing Solutions for Anterior Cruciate Ligament-Deficient Knees

Our evolving understanding of ramp lesions has significantly affected the field of anterior cruciate ligament injury and meniscal repair. Although these lesions have been linked consistently to increased anterior and rotational instability in anterior cruciate ligament-deficient knees, there remains a contentious debate regarding their optimal treatment. The current literature is divided, as some advocate for surgical repair of only arthroscopically unstable lesions. Others point to a substantial risk of complications, noting a 28.6% incidence in untreated stable lesions, and thus advocate for surgical repair of all lesions. Through the use of magnetic resonance imaging scans of flexed knees, a novel subclassification of ramp lesions based on gap distance at the tear site shows a correlation with posterior capsular displacement, anterior laxity, lesion size, and joint effusion. This nuanced classification offers new insights and promises to refine treatment decisions, potentially minimizing unnecessary surgeries and improving patient outcomes.

Efficacy of all-inside devices in reducing gap and step-off in knee extension for ramp lesion repair: A cadaveric study

PURPOSE

The aim of this study is to assess the dynamics of the tear site of meniscal ramp lesions, particularly considering knee flexion angles, and validate anchor fixation using an all-inside device.

METHODS

Eight Thiel-embalmed paired cadaveric knees with their whole bodies were used in this study. The ramp lesions were created arthroscopically, and ramp lesion dynamics were evaluated by gradually extending the knee from 90° of knee flexion. Changes in the gap and step-off (0: no step-off; 1: cross-sectional overlap exists; and 2: tibial articular surface exposed) were evaluated at 90°, 60°, 30°, and 10° of knee flexion. After dynamic evaluation, all-inside repairs of the ramp lesions using all-inside devices were conducted. Dissection was performed to confirm the position of anchor fixation.

RESULTS

As the knee was extended, the gap significantly decreased at all knee flexion angles. Similarly, the step-off grade decreased as the knee was extended, and the step-off completely disappeared in all cases when the knee was extended from 30° to 10°. The average knee flexion angle at which the gap and step-off completely disappeared was 22.5°. After suturing the ramp lesion, arthroscopic evaluation showed that the gap had disappeared and the step-off had been repaired in all cases. Anchor fixation locations were not found within the joint but were fixed to the semimembranosus tendon or its surrounding articular capsule. Overall, 31% (5/16) anchors were fixed to the attachment site of the semimembranosus tendon, whereas the remaining were fixed to the articular capsule, located peripherally to the semimembranosus tendon.

CONCLUSION

Suturing with an all-inside device for ramp lesions is a good option, and the repair in knee extension was found to be reasonable, considering the dynamics of ramp lesions in this study.

LEVEL OF EVIDENCE

Level IV.

Posteromedial tibial plateau bone bruises are associated with medial meniscal ramp lesions in patients with concomitant anterior cruciate ligament ruptures: a systematic review & meta-analysis

OBJECTIVE

To determine if posteromedial tibial plateau (PMTP) bone bruising on pre-operative MRI is significantly associated with a ramp lesion identified during arthroscopy in patients with concomitant ACL ruptures.

METHODS

PubMed, CINAHL, Scopus, Web of Sciences, EMBASE, and Cochrane Library were searched systematically for studies that investigated the association between PMTP bone bruises on preoperative MRI and ramp lesions confirmed during arthroscopy. Eight studies met inclusion criteria. The Methodological Index for Nonrandomized Studies (MINORS) checklist was used to assess quality. A meta-analysis was performed to analyze odds of a ramp lesion after PMTP bone bruising identified on magnetic resonance imaging (MRI). Publication bias was assessed by funnel plot and Egger's linear regression test.

RESULTS

There are 2.05 greater odds of medial meniscal ramp lesions in patients with an ACL rupture when PMTP bone bruising is found on preoperative MRI (95% CI, 1.29-3.25; p = 0.002). Heterogeneity of the pooled studies may be substantial (I2 = 65%; p = 0.006). Funnel plot analysis and Egger's linear regression test (p > 0.5) determined no publication bias among the studies included in the meta-analysis.

CONCLUSION

Patients with acute ACL injuries and PMTP bone bruising on MRI have 2.05 times greater odds of a concomitant medial meniscal ramp lesion than those without this bone bruise pattern.

Ramp lesion in anterior cruciate ligament injury: a review of the anatomy, biomechanics, epidemiology, and diagnosis

Ramp lesions, commonly observed in patients with anterior cruciate ligament (ACL) injuries, have been previously defined as longitudinal tears around the meniscocapsular junction. However, the definitions and interpretations of ramp lesions have varied, emphasizing the need to confirm their presence before surgery and the importance of direct visualization using arthroscopy. Recent histological studies have reported new findings on ramp lesions, shedding light on their attachment mechanisms. The anatomical structures around the ramp lesion, such as the posterior horn of medial meniscus (PHMM), semimembranosus (SM), posteromedial (PM) capsule, and meniscotibial ligament (MTL), were assessed regarding how these structures could be attached to each other. The studies of ramp lesions have also contributed to the progression of biomechanical studies explaining the cause and effects of ramp lesions. Ramp lesion has been proven to stabilize the anteroposterior (AP) instability of ACL. In addition, various laboratory studies have demonstrated the relationship between rotational instability of the knee joint and ramp lesions. The analysis of risk factors of ramp lesion helped to understand the injury mechanism of the lesion. Many authors have evaluated the prevalence of ramp lesions in patients with ACL injuries. The development of arthroscopy techniques has influenced the outcomes of ACL reconstruction with the easy detection of ramp lesions. This review article aims to analyze the past findings and recent advancements in anatomical, biomechanical, and epidemiological studies of ramp lesions in patients who underwent ACL reconstruction, and provide various perspectives ramp lesions in patients with ACL reconstruction.

Knee MRI: Meniscus Roots, Ramps, Repairs, and Repercussions

Menisci play an essential role in maintaining normal pain-free function of the knee. While there are decades of MRI literature on the tears involving the meniscus body and horns, there is now a surge in knowledge regarding injuries at the meniscus roots and periphery. The authors briefly highlight new insights into meniscus anatomy and then summarize recent developments in the understanding of meniscus injuries that matter, emphasizing meniscus injuries at the root and peripheral (eg, ramp) regions that may be missed easily at MRI and arthroscopy. Root and ramp tears are important to diagnose because they may be amenable to repair. However, if these tears are left untreated, ongoing pain and accelerated cartilage degeneration may ensue. The posterior roots of the medial and lateral menisci are most commonly affected by injury, and each of these injuries is associated with distinctive clinical profiles, MRI findings, and tear patterns. Specific diagnostic pitfalls can make the roots challenging to evaluate, including MRI artifacts and anatomic variations. As with root tears, MRI interpretation and orthopedic treatment have important differences for injuries at the medial versus lateral meniscus (LM) periphery (located at or near the meniscocapsular junction). Medially, ramp lesions typically occur in the setting of an anterior cruciate ligament rupture and are generally classified into five patterns. Laterally, the meniscocapsular junction may be injured in association with tibial plateau fractures, but disruption of the popliteomeniscal fascicles may also result in a hypermobile LM. Updated knowledge of the meniscus root and ramp tears is crucial in optimizing diagnostic imaging before repair and understanding the clinical repercussions. ©RSNA, 2023 Online supplemental material is available for this article. Quiz questions for this article are available in the Online Learning Center.

Meniscal Ramp Lesions in Adolescent Patients Undergoing Primary Anterior Cruciate Ligament Reconstruction: Significance of Imaging and Arthroscopic Findings

BACKGROUND

Meniscal ramp lesions are associated with anterior cruciate ligament (ACL) injuries and may affect knee stability when left untreated. The diagnostic accuracy of magnetic resonance imaging (MRI) to identify this meniscocapsular injury of the posterior horn of the medial meniscus remains poor, and the arthroscopic findings require vigilance.

PURPOSE

To determine the concordance of arthroscopic and MRI findings to better identify the presence of a ramp lesion in children and adolescent patients undergoing primary ACL reconstruction.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 2.

METHODS

Patients aged <19 years who underwent primary ACL reconstruction at a single institution between 2020 and 2021 were included. Two cohorts were developed by the presence of a ramp lesion arthroscopically. Basic patient descriptive data, preoperative imaging (radiologist assessment and independent reviewer assessment), and concomitant arthroscopic findings at the time of ACL reconstruction were recorded.

RESULTS

An overall 201 adolescents met criteria with a mean age of 15.7 years (range, 6.9-18.2) at the time of injury. A ramp lesion was identified in 14% of patients (28 children). No differences were detected between cohorts with regard to age, sex, body mass index, weeks from injury to MRI, or weeks from injury to surgery (P > .15). The primary predictor of an intraoperative ramp lesion was the presence of medial femoral condylar striations, with an adjusted odds ratio of 722.2 (95% CI, 59.5-8768.2; P < .001); the presence of a ramp lesion on MRI had an adjusted odds ratio of 11.1 (95% CI, 2.2-54.8; P = .003). Patients with neither a ramp lesion on MRI nor medial femoral condylar striations had a 2% rate (2/131) of ramp lesion; those with either of the significant risk factors had a 24% rate (14/54). All patients with both risk factors (100%; n = 12) had a ramp lesion noted on intraoperative examination.

CONCLUSION

The concordance of medial femoral condylar chondromalacia, particularly striations, noted during arthroscopy and posteromedial tibial marrow edema on MRI with or without direct evidence of posterior meniscocapsular pathology should increase suspicion for the presence of a ramp lesion in adolescents undergoing ACL reconstruction.

Over One-Third of Patients With Multiligament Knee Injuries and an Intact Anterior Cruciate Ligament Demonstrate Medial Meniscal Ramp Lesions on Magnetic Resonance Imaging

PURPOSE

To determine the incidence of ramp lesions and posteromedial tibial plateau (PMTP) bone bruising on magnetic resonance imaging (MRI) in patients with multiligament knee injuries (MLKIs) and an intact anterior cruciate ligament (ACL).

METHODS

A retrospective review of consecutive patients surgically treated for MLKIs at 2 level I trauma centers between January 2001 and March 2021 was performed. Only MLKIs with an intact ACL that received MRI scans within 90 days of the injury were included. All MLKIs were diagnosed on MRI and confirmed with operative reports. Two musculoskeletal radiologists retrospectively rereviewed preoperative MRIs for evidence of medial meniscus ramp lesions (MMRLs) and PMTP bone bruises using previously established classification systems. Intraclass correlation coefficients were used to calculate the reliability between the radiologists. The incidence of MMRLs and PMTP bone bruises was quantified using descriptive statistics.

RESULTS

A total of 221 MLKIs were identified, of which 32 (14.5%) had an intact ACL (87.5% male; mean age of 29.9 ± 8.6 years) and were included. The most common MLKI pattern was combined injury to the posterior cruciate ligament and posterolateral corner (n = 27, 84.4%). PMTP bone bruises were observed in 12 of 32 (37.5%) patients. Similarly, MMRLs were diagnosed in 12 of 32 (37.5%) patients. A total of 8 of 12 (66.7%) patients with MMRLs demonstrated evidence PMTP bone bruising.

CONCLUSIONS

Over one-third of MLKI patients with an intact ACL were diagnosed with MMRLs on MRI in this series. PMTP bone bruising was observed in 66.7% of patients with MMRLs, suggesting that increased vigilance for identifying MMRLs at the time of ligament reconstruction should be practiced in patients with this bone bruising pattern.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Editorial Commentary: Arthroscopy Is the Gold Standard for Diagnosis of Meniscal Ramp Lesions: Magnetic Resonance Imaging Also May Be Helpful

Identifying and treating medial meniscal ramp lesions in conjunction with ligament reconstruction restores critical stability in knees with ligament injuries. This must begin with obtaining high-quality magnetic resonance imaging (MRI) and critical evaluation of the MRI and include a subsequent thorough arthroscopic examination of these knees. As evident in previous studies, most surgeons associate medial meniscal ramp lesions with anterior cruciate ligament (ACL) tears. Biomechanical studies have reported that a ramp lesion produces significant anterior tibial translation and external rotational instability in ACL-deficient knees that is not reestablished with an isolated ACL reconstruction. In addition, recent research identified ramp lesions in one-third of multiligament knee injuries with an intact ACL and two-thirds of patients with posteromedial tibial plateau bone bruises on MRI. Restoring knee stability and biomechanics is necessary in treating all knee ligament injuries. Don't miss the meniscal ramp lesion. Have a high index of suspicion, obtain a high-quality MRI,and arthroscopically evaluate the meniscocapsular junction of the medial meniscus, especially if there is a bone bruise seen on MRI.

Reproducibility of MRI in the diagnosis of meniscal ramp lesions: an inter-observer study

BACKGROUND

Meniscal ramp lesions have gained much prominence in recent years due to a significant increase in their diagnosis and their important biomechanical involvement in the knee. A new proposed classification of these lesions has recently been published.

PURPOSE

To evaluate the reproducibility of the new classification of meniscal ramp lesions recently published using magnetic resonance imaging (MRI).

MATERIAL AND METHODS

A total of 249 post-traumatic knee MRI studies were evaluated by three musculoskeletal radiologists independently. Patients with an anterior cruciate ligament (ACL) tear on MRI in addition to a recent history of trauma to the knee for <12 months were included in the study, for a total of 95. We carried out an inter-observer concordance study to analyze whether the new classification is reproducible to detect meniscal ramp lesions and to classify them into their different types.

RESULTS

Among our study cohort of 95 patients, we found 47 (49.5%) ramp lesions. In the inter-observer study, we obtained a good concordance (k = 0.733) in the detection of these lesions and an excellent one (k = 0.843) when the type of lesion is described.

CONCLUSION

This study demonstrates that the new classification of meniscal ramp lesions has good reproducibility on MRI.

Study of the nerve endings and mechanoreceptors of the medial meniscotibial ligament of the knee: A structural and distribution analysis

BACKGROUND

The aim of the present study is to describe the morphology and distribution of the nerve endings of the meniscotibial ligament (MTL) of the knee, in order to understand the interaction between the proprioceptive system and knee mechanics.

METHODS

Twenty medial MTLs were obtained from deceased organ donors. The ligaments were measured, weighed and cut. Sections (10 mm) were prepared on hematoxylin and eosin-stained slides for analysis of tissue integrity, and 50 mm sections were submitted to immunofluorescence with the protein gene product (PGP) 9.5 as primary antibody and Alexa Fluor 488 as secondary antibody, followed by microscopic analysis.

RESULTS

The medial MTL was identified in 100% of the dissections, with average length, width, thickness and weight of 7.07 ± 1.34 mm, 32.25 ± 3.09 mm, 3.53 ± 0.27 mm and 0.67 ± 0.13 g, respectively. The hematoxylin and eosin-stained histological sections exhibited typical ligament structure, with dense well-organized collagen fibers and vascular tissue. All the specimens analyzed contained type I (Ruffini) mechanoreceptors and free (type IV) nerve endings, varying from parallel to intertwined fibers. Nerve endings not classified with different irregular shapes were also found. Most type I mechanoreceptors were found close to the MTL insertions on the tibial plateau, while the free nerve endings were found adjacent to the capsule.

CONCLUSION

The medial MTL showed a peripheral nerve structure, primarily type I and IV mechanoreceptors. These findings suggest that the medial MTL is important for proprioception and medial knee stabilization.

The anterior cruciate ligament injury severity scale (ACLISS) is an effective tool to document and categorize the magnitude of associated tissue damage in knees after primary ACL injury and reconstruction

PURPOSE

To develop a tool allowing to classify the magnitude of structural tissue damage occurring in ACL injured knees. The proposed ACL Injury Severity Scale (ACLISS) would provide an easy description and categorization of the wide spectrum of injuries in patients undergoing primary ACL reconstruction, reaching from isolated ACL tears to ACL injuries with a complex association of combined structural damage.

METHODS

A stepwise approach was used to develop the ACLISS. The eligibility of each item was based on a literature search and a consensus between the authors after considering the diagnostic modalities and clinical importance of associated injuries to the menisci, subchondral bone, articular cartilage or collateral ligaments. Then, a retrospective analysis of associated injuries was performed in 100 patients who underwent a primary ACL reconstruction (ACLR) by a single surgeon. This was based on acute preoperative MRI (within 8 weeks after injury) as well as intraoperative arthroscopic findings. Depending on their prevalence, the number of selected items was reduced. Finally, an analysis of the overall scale distribution was performed to classify the patients according to different injury profiles.

RESULTS

A final scoring system of 12 points was developed (12 = highest severity). Six points were attributed to the medial and lateral tibiofemoral compartment respectively. The amount of associated injuries increased with ACLISS grading. The median scale value was 4.5 (lower quartile 3.0; higher quartile 7.0). Based on these quartiles, a score < 4 was considered to be an injury of mild severity (grade I), a score between ≥ 4 and ≤ 7 was defined as moderately severe (grade II) and a score > 7 displayed the most severe cases of ACL injuries (grade III). The knees were graded ACLISS I in 35%, ACLISS II in 49% and ACLISS III in 16% of patients. Overall, damage to the lateral tibiofemoral compartment was predominant (p < 0.01), but a proportional increase of tissue damage could be observed in the medial tibiofemoral compartment with the severity of ACLISS grading (p < 0.01).

CONCLUSIONS

The ACLISS allowed to easily and rapidly identify different injury severity profiles in patients who underwent primary ACLR. Injury severity was associated with an increased involvement of the medial tibiofemoral compartment. The ACLISS is convenient to use in daily clinical practice and represents a feasible grading and documentation tool for a reproducible comparison of clinical data in ACL injured patients.

LEVEL OF EVIDENCE

Level III.

High prevalence of meniscal ramp lesions in anterior cruciate ligament injuries

PURPOSE

To evaluate the prevalence of and factors associated with meniscal ramp lesions on magnetic resonance imaging (MRI) in patients with anterior cruciate ligament (ACL) injuries.

METHODS

Data from the Natural Corollaries and Recovery after ACL injury multicentre longitudinal cohort study (NACOX) were analysed. Only patients who underwent MRI were included in this study. All MRI scans were reviewed by an orthopaedic knee surgeon and a musculoskeletal radiologist. The patients were divided into two groups, those with and without ramp lesions according to MRI findings. Univariable and stepwise forward multiple logistic regression analyses were used to evaluate patient characteristics (age, gender, body mass index, pre-injury Tegner activity level, activity at injury) and concomitant injuries on MRI (lateral meniscus, medial collateral ligament [MCL], isolated deep MCL, lateral collateral ligament, pivot-shift-type bone bruising, posteromedial tibial [PMT] bone bruising, medial femoral condyle bone bruising, lateral femoral condyle [LFC] impaction and a Segond fracture) associated with the presence of meniscal ramp lesions.

RESULTS

A total of 253 patients (52.2% males) with a mean age of 25.4 ± 7.1 years were included. The overall prevalence of meniscal ramp lesions was 39.5% (100/253). Univariate analyses showed that contact sports at ACL injury, pivot-shift-type bone bruising, PMT bone bruising, LFC impaction and the presence of a Segond fracture increased the odds of having a meniscal ramp lesion. Stepwise forward multiple logistic regression analysis revealed that the presence of a meniscal ramp lesion was associated with contact sports at ACL injury [odds ratio (OR) 2.50; 95% confidence intervals (CI) 1.32-4.72; P = 0.005], pivot-shift-type bone bruising (OR 1.29; 95% CI 1.01-1.67; P = 0.04), PMT bone bruising (OR 4.62; 95% CI 2.61-8.19; P < 0.001) and the presence of a Segond fracture (OR 4.38; 95% CI 1.40-13.68; P = 0.001).

CONCLUSION

The overall prevalence of meniscal ramp lesions in patients with ACL injuries was high (39.5%). Contact sports at ACL injury, pivot-shift-type bone bruising, PMT bone bruising and the presence of a Segond fracture on MRI were associated with meniscal ramp lesions. Given their high prevalence, meniscal ramp lesions should be systematically searched for on MRI in patients with ACL injuries. Knowledge of the factors associated with meniscal ramp lesions may facilitate their diagnosis, raising surgeons' and radiologists' suspicion of these tears.

LEVEL OF EVIDENCE

III.

Diagnosis of medial meniscal ramp lesion is difficult by pre-operative magnetic resonance imaging evaluation and needs a methodical arthroscopic exploration

BACKGROUND

Meniscal ramp lesion (RL) is the peripheral lesion of the posterior horn of the medial meniscus (PHMM) associated with anterior cruciate ligament (ACL) tear. The purpose of this study was to evaluate the accuracy of pre-operative magnetic resonance imaging (MRI) evaluation in diagnosing RL and to identify whether the difficulty in diagnosis differs depending on the location of RL.

METHODS

ACL-injured patients undergoing ACL reconstruction from January 2017 to January 2019 were enrolled. A methodical arthroscopic exploration to identify RL was conducted intra-operatively using three steps, namely, the anterior visualization step, the inter-condylar visualization step, and the posteromedial step. The location of the RLs was evaluated and classified into two types as follows: Red-red zone (RR) - a meniscal tear of the red-red zone of the PHMM. Menisco-capsular junction (MCJ) - a lesion at the menisco-capsular junction of the PHMM, which is more peripheral than RR. Furthermore, the accuracy of 1.5-T MRI evaluation to diagnose RL by two testers using sagittal proton-density fat-saturated images was calculated.

RESULTS

Of the 81 patients enrolled, 11 had RL: 5 cases each were at the MCJ and RR, and 1 case was at both locations. The sensitivity of MRI for detecting RL was 27.3-45.5%, whereas the specificity was 84.3-95.7% in total. The sensitivity of MRI in detecting RL at the RR and MCJ was 40.0-80.0%, 0-20.0%, respectively. The intra-observer reliability of the MRI evaluation was moderate (κ coefficient: 0.40-0.46), while the inter-observer reliability was fair to moderate (κ coefficient: 0.27-0.41).

CONCLUSIONS

A low sensitivity of the MRI in detecting RL at the MCJ was observed, and the reliability of the MRI evaluation for diagnosis of RL was not high. Therefore, methodical arthroscopic exploration is essential to diagnose RL even when it is not suspected on pre-operative MRI.

All-Inside Technique for Ramp Lesion Repair: Arthroscopic Suture With Knee Scorpion Suture Passer

Ramp lesions are peripheral tears of the posterior horn of the medial meniscus that involve the meniscocapsular attachments. They are commonly associated with anterior cruciate ligament injury and frequently not diagnosed. There are several suture techniques for ramp lesions. However, most have a long learning curve to be performed adequately and to minimize the risks of neurovascular lesions, cartilage injury, as well as damage to the meniscotibial ligament and meniscus. Thus, as an alternative to minimize costs and provide adequate ramp lesion repair, we present a simple, easy-to-reproduce technique using a Scorpion Suture Passer and all-inside sutures, without the need to leave devices inside the knee, causing no additional lesions and making it less costly than conventional methods. Our technique, which consists of a biomechanically strong suture, with no internal devices, is cheaper, allows several sutures with the same thread and produces satisfactory clinical results.

Ramp lesion repair via dual posteromedial arthroscopic portals: A cadaveric feasibility study

BACKGROUND

Ramp lesions are found in 16% to 40% of patients undergoing anterior cruciate ligament reconstruction. The repair technique traditionally involves using a suture hook through a posteromedial portal, with the arthroscope positioned in the intercondylar view via an antero-lateral portal. Ramp lesions may be difficult to visualize and repair, even with a 70° arthroscope. The objective of this study was to assess the feasibility of suturing ramp lesions via dual posteromedial portals for the arthroscope and instruments.

HYPOTHESIS

Dual posteromedial arthroscopic portals allow good visualisation and high-quality suturing of ramp lesions, without inducing specific iatrogenic injuries.

MATERIAL AND METHODS

We used 11 fresh cadaver knees. Two posteromedial portals were created under visualisation via an arthroscope introduced through an antero-lateral portal: one was the traditional instrumental portal and the other, located more proximally, was the optical portal. A 2-cm long ramp lesion was created. A suture hook was used to place one or two stitches of PDS n°0 suture. A probe was used to test the quality and stability of the suturing. The posteromedial plane was then dissected to evaluate the anatomical relationships of the portals.

RESULTS

The dual posteromedial approach allowed the visualisation and hook suturing of the ramp lesions in all 11 cases. A single stitch was placed in 4 cases and two stitches in 7 cases. The suture was always of good quality and stable when tested with the probe. The dissection found no injuries to nerves, blood vessels, or tendons.

CONCLUSION

Ramp lesions can be repaired through a dual posteromedial arthroscopic approach. This surgical technique provides good visibility of these lesions and allows high-quality suturing, with no specific iatrogenic injuries. It is an alternative to ramp lesion repair via a single posteromedial portal, which can be challenging.

LEVEL OF EVIDENCE

IV, experimental study with no control group.

Short-Term Outcomes After Treatment of Isolated Hidden Meniscal Ramp Lesions

Background:

Ramp lesions are encountered in 16% to 24% of all anterior cruciate ligament (ACL) ruptures. However, isolated ramp lesions without a ruptured ACL have also been reported.

Purpose:

To evaluate outcomes after type 3 hidden ramp lesions without ACL rupture were treated with all-inside sutures passed through the standard anterior portal.

Study Design:

Case series, Level of evidence, 4.

Methods:

Included were 41 patients (26 female; 63.4%) with isolated type 3 ramp lesions who underwent surgery between January 2017 and January 2019. Patients with concomitant lateral meniscal injuries and revision meniscal surgeries were excluded. We retrospectively recorded patient age, sex, and body mass index (BMI), as well as follow-up periods, comorbidities, and postoperative and early midterm complications. The Lysholm, visual analog scale (VAS) for pain, and International Knee Documentation Committee (IKDC) scores were compared preoperatively to final follow-up. In addition, patients were classified as having either a sedentary or active lifestyle according to Sedentary Behavior Research Network (SBRN) criteria. The Shapiro-Wilk test was used to evaluate the normality of the data, and the Wilcoxon and Mann-Whitney U tests were used to compare preoperative and postoperative outcome scores. The Spearman test was employed to evaluate the correlation between patient variables.

Results:

The mean follow-up period was at 37.6 (range, 25-49) months. A total of 17 patients (41.46%) had a sedentary lifestyle based on SBRN criteria. All scores improved significantly from preoperatively to final follow-up (VAS, from 8.43 ± 1.53 to 2.34 ± 2.9; Lysholm, from 47.73 ± 17.02 to 85.37 ± 14.01; and IKDC, from 27.12 ± 14.81 to 85.32 ± 8.78; P < .001 for all). Although no significant relationship was established between patient activity level and postoperative Lysholm and IKDC scores, an inverse correlation was observed between BMI and Lysholm (r =–0.9906) and BMI and IKDC (r =–0.9402).

Conclusion:

Satisfactory postoperative clinical results were obtained in patients with type 3 ramp lesions not accompanied by ACL rupture who were treated with all-inside suturing through standard anterior portals.

Meniscal Ramp Lesions: Anatomy, Epidemiology, Diagnosis, and Treatment

Injuries to the medial meniscus meniscocapsular junction, also known as ramp lesions, are common in the setting of anterior cruciate ligament injuries with a prevalence of 9% to 42%. Anatomically, ramp lesions involve disruption of the posterior meniscocapsular junction and meniscotibial ligaments. Biomechanically, ramp lesions are associated with an increase in anterior tibial translation and internal and external tibial rotation in anterior cruciate ligament-deficient cadaveric knees. Magnetic resonance imaging is useful in evaluating the meniscocapsular junction. Irregularity or increased signal near the posterior meniscocapsular junction and/or signal change indicative of posterior medial tibial plateau edema can suggest these injuries are present before surgical intervention. The current benchmark for diagnosis is arthroscopic visualization of the posterior medial meniscocapsular junction viewed through the intercondylar notch. Once a ramp lesion is identified, stability should be assessed by arthroscopic probing to determine the degree of anterior displacement. Optimal treatment has been debated in the literature, especially for stable ramp lesions, although good outcomes have been shown with and without repair. Repair is warranted for those lesions that are unstable to probing. Unfortunately, only limited literature available to guide clinicians on the optimal rehabilitation for ramp lesions.

The accuracy of MRI for the diagnosis of ramp lesions

OBJECTIVES

To assess the diagnostic accuracy of MRI in diagnosing ramp lesions in patients with an acute lesion of the anterior cruciate ligament (ACL).

MATERIALS AND METHODS

All consecutive patients over 15 years of age who underwent surgical repair of the ACL at a single hospital between January and May 2019, with MRI data available, were included in this retrospective study, except patients who had previous knee surgery. The gold standard was arthroscopic evaluation. Two trained radiologists with 5 and 14 years of experience did a blinded review of the MRIs. The following pathological signs were studied: complete fluid filling between the capsule and the posterior horn of the medial meniscus, irregular appearance of the posterior wall of the medial meniscus, oedema of the capsule, fluid hyperintensity in contact with the medial meniscus and anterior subluxation of the medial meniscus. Logistic regressions in univariate then multivariate analysis were carried out and measures of diagnostic accuracy and interobserver agreement were calculated with R software (version 3.6).

RESULTS

Fifty-seven patients were included. Twelve had a ramp lesion diagnosed by arthroscopy (21%). Only complete fluid hyperintensity between the posterior horn of the medial meniscus and the capsule was significantly associated with ramp lesions (P value < 0.01). The diagnostic accuracy of this specific sign was moderate, with a specificity of 84%, sensitivity of 75%, PPV of 56%, NPV of 93% and a good level of inter-observer agreement (k = 0.79).

CONCLUSION

The complete fluid filling is the only significant pathological MRI sign for ramp lesions, with moderate accuracy.

Novel type of medial meniscus ramp lesion: a case report and surgical technique

Meniscal ramp lesions have been reported in 9-24% of patients who underwent anterior cruciate ligament reconstruction (ACLR). We report a rare type of double medial meniscus ramp lesion in in a 26-year-old male soccer player who presented with persistent knee instability and an inability to return to sports after a successful ACLR due to unaddressed and untreated ramp lesions. To the best of our knowledge, this is the first reported case of a double ramp lesion, with tears occurring in two separate locations: one tear at the meniscosynovial junction and associated with meniscotibial ligament disruption; and a second, more posteriorly located at the meniscocapsular junction and associated with meniscocapsular attachment disruption. It was found to be very unstable upon arthroscopic assessment and was clinically associated with persistent knee instability even after ACLR, thus necessitating surgical repair to restore knee kinematics.

Leaving the stable ramp lesion unrepaired does not negatively affect clinical and functional outcomes as well as return to sports rates after ACL reconstruction

PURPOSE

To evaluate the effects of untreated stable ramp lesions on clinical and functional outcomes, return to sports rates, and complications of patients who underwent anterior cruciate ligament reconstruction.

METHODS

A total of 879 patients with anterior cruciate ligament rupture were evaluated. Of these, 66 patients [33 patients with anterior cruciate ligament rupture and stable medial meniscal ramp lesion (ramp + group) and 33 patients with isolated anterior cruciate ligament rupture (ramp - group)] with a minimum 3-year of follow-up were included. Stable ramp lesions were not repaired in the ramp + group. Preoperative and postoperative Lachman and pivot-shift grades, Lysholm knee scores, International Knee Documentation Committee score and 12-Item Short Form Health Survey score were compared between groups. The return to sports rates, level of return to sports, time to return to sports and complications were compared.

RESULTS

The mean patient age was 27.8 ± 7.2 years. The mean follow-up period was 47.3 ± 9.4 months. There were no significant differences between groups regarding preoperative and postoperative Lachman and pivot-shift grades, 12-Item Short Form Health Survey mental and physical component summary scores, Lysholm and International Knee Documentation Committee scores, and complication rates (n.s.). Although the return to sports rates (84.8% vs 90.1%) and the level of the return to sports (return to preinjury level: 75% vs 78%) were similar between groups (n.s.), the time to return to sports was significantly longer for patients with ramp lesions (11.1 ± 4.0 vs. 8.7 ± 2.5 months, p = 0.007).

CONCLUSION

Leaving the stable ramp lesion unrepaired does not negatively affect clinical and functional outcomes as well as return to sports rates after ACL reconstruction. However, the time to return to sports is prolonged in patients with ramp lesions In clinical practice, surgeons should be aware that repairing stable ramp lesions is not an absolute necessity and will not affect return to sport rates.

LEVEL OF EVIDENCE

Level III.

Risk Factors for Ramp Lesions of the Medial Meniscus: A Systematic Review and Meta-analysis

BACKGROUND

Failure to appropriately identify and repair medial meniscal ramp lesions at the time of anterior cruciate ligament (ACL) reconstruction (ACLR) may result in increased anterior tibial translation and internal rotation, increasing the risk for graft failure. Knowledge of the risk factors leading to the development of ramp lesions may enhance clinicians' vigilance in specific ACL-deficient populations and subsequently repair of these lesions at the time of ACLR.

PURPOSE

To perform a systematic review and meta-analysis of factors tested for associations with ramp lesions and to determine which were significantly associated with the presence of ramp lesions.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 4.

METHODS

PubMed, OVID/Medline, and Cochrane databases were queried in April 2020. Data pertaining to study characteristics and reported risk factors for ramp lesions were recorded. DerSimonian-Laird binary random-effects models were constructed to quantitatively evaluate the association between risk factors and ramp lesions by generating effect estimates in the form of odds ratios (ORs) with 95% CIs. Qualitative analysis was performed to describe risk factors that were variably reported.

RESULTS

The review included 12 studies with 8410 patients. The overall pooled prevalence of ramp lesions was 21.9% (range, 9.0%-41.7%). A total of 45 risk factors were identified, of which 8 were explored quantitatively. There was strong evidence to support that posteromedial tibial edema on magnetic resonance imaging (MRI) (OR, 2.12; 95% CI, 1.27-3.56; P = .004), age <30 years (OR, 2.02; 95% CI, 1.23-3.22; P = .002), and complete ACL tears (OR, 3.0; 95% CI, 1.41-6.20; P = .004) were risk factors for ramp lesions. There was moderate evidence to support that male sex (OR, 1.58; 95% CI, 1.36-1.83; P < .001) and concomitant lateral meniscal tears (OR, 1.54; 95% CI, 1.11-2.13; P = .009) were risk factors for ramp lesions. Chronic ACL injury (≥24 months) demonstrated minimal evidence as a risk factor (OR, 1.41; 95% CI, 1.14-1.74; P = .001). No significant associations were determined between contact injury or revision ACLR and the presence of ramp lesions.

CONCLUSION

Significant associations between male sex, age <30 years, posteromedial tibial edema on MRI, concomitant lateral meniscal tears, complete ACL tears, injury chronicity, and the presence of ramp lesions were found. Contact injury and revision ACLR were not significantly associated with the presence of ramp lesions.

Editorial Commentary: The Importance of Bony Morphology in the Anterior Cruciate Ligament-Injured Patient

The outcome of anterior cruciate ligament (ACL) surgery depends on many factors. Successful ACL surgery includes evaluating patients' characteristics and addressing all the underlying knee pathologies, including the meniscus tears and ramp lesions. In recent years, there has been a growing interest in ramp lesions as well as the role that bony morphology plays in predisposing patients to ACL injury and failed ACL surgery. Not only pathologic but also physiologic variations in bony morphology like tibial slope and lateral femoral condyle ratio have been correlated with clinical outcomes, failure rates, rotatory instability, and even lesions to the contralateral knee. Evaluating each patient's specific anatomy is recommended when customizing ACL surgery. With further research and increased awareness of relevant bony parameters, we will be able to improve our ability to prevent injury, increase the diagnostic accuracy of associated lesions, and tailor surgery to improve the outcomes and reduce failure rates.

Meniscal ramp lesions: an illustrated review

The purpose of this review is to describe the anatomy and lesions affecting the peripheral portion of posterior horn of medial menisci (ramp lesions), along with illustrations and MRI cases. We will correlate imaging features with arthroscopic classification of ramp lesions. Also, postoperative and chronic changes related to meniscocapsular tears will be presented, as well as biomechanical consequences and treatment approach.

Prevalence and Detection of Meniscal Ramp Lesions in Pediatric Anterior Cruciate Ligament-Deficient Knees

BACKGROUND

Anterior cruciate ligament (ACL) tears represent 13% of knee injuries in children. Medial meniscal tears are commonly associated with ACL ruptures. Ramp lesions correspond to posterior meniscocapsular tears of the medial meniscus. Depending on the study, the prevalence of ramp lesions is inconsistent.

PURPOSE

To describe the prevalence of ramp lesions in children and adolescents and to investigate the sensitivity of magnetic resonance imaging (MRI) for diagnosing such lesions.

STUDY DESIGN

Cohort study (Diagnosis); Level of evidence, 3.

METHODS

We analyzed videos from arthroscopic ACL reconstruction (ACLR) in children. During these procedures, we systematically looked for potential ramp lesions. To do so, an arthroscope was passed through the intercondylar notch to visualize the posteromedial compartment. A needle was introduced at the site of a posteromedial portal to unfold the meniscocapsular junction to reveal any hidden meniscal tear. Surgical procedures were performed by 2 senior surgeons. Videos were blindly analyzed by a third surgeon. Preoperative MRIs were screened by 2 blinded, independent senior radiologists to look specifically for ramp lesions.

RESULTS

Videos of 50 consecutive arthroscopic ACLRs concerning 32 boys and 18 girls were analyzed. Mean age at surgery was 14.2 years (range, 8.5-17.6 years). A total of 14 ramp lesions (28%) in 8 boys and 6 girls were identified. In addition, there were 22 tears of the meniscal body in 20 patients (40%). Arthroscopic and MRI findings did not correlate. Among 14 arthroscopically diagnosed ramp lesions, only 8 were detected on the MRI. Conversely, 12 patients had a ramp lesion detected on the MRI, which could not be confirmed intraoperatively. The sensitivity of MRI was 57% and the positive predictive value was 40%.

CONCLUSION

A meniscal ramp lesion was present in 14 of 50 children (28%) undergoing ACLR. MRI has a low sensitivity for diagnosis of ramp lesions in children. Careful exploration of the posteromedial compartment is strongly recommended. Overlooking such lesions during ACLR may contribute to ongoing instability and higher re-rupture rates in these young patients.

Arthroscopic Imaging Treatment and Clinical Rehabilitation of Knee Sports Injuries

This article studies the effects of arthroscopic imaging treatment and clinical rehabilitation of knee sports injuries. Arthroscopy was used to perform meniscus trimming and resection for 40 patients with knee sports injuries. The ages of the patients ranged from 20 to 60 years old. All patients received routine rehabilitation training such as continuous passive motion of the knee joint, biofeedback of the lower limbs, and air pressure therapy of the lower limbs. In addition, the control group was given muscle strength training, and the training began after the patients received the quadriceps muscle strength test. The removal of the joint cavity and the joint debridement has achieved satisfactory treatment results. In the experiment, the test cases were divided into two groups, and the sensor test platform was used for signal collection. Normal activities can be resumed 2 weeks after the operation. After a follow-up of 6 to 24 months, the knee joint pain disappeared, the joint was free of swelling, and the knee function was normal up to 93%. Arthroscopic reconstruction of the anterior and posterior cruciate ligament joint repair/reconstruction of the medial and posterolateral ligament knots is safe and feasible for the treatment of multiple ligament injuries of the knee joint. It has the advantages of less trauma and quick recovery. Early postoperative systemic and standardized rehabilitation exercises can obtain good knee joint function.

How to Detect Meniscal Ramp Lesions Using Ultrasound

The clinical importance of meniscal ramp lesions in patients with anterior cruciate ligament tears has emerged. However, the diagnostic accuracy of magnetic resonance imaging for detecting meniscal ramp lesions is low. The advantage of ultrasonography is that it can be performed in any position and is a real-time imaging modality. The goal of this Technical Note is to describe in detail the ultrasound technique that we use to detect meniscal ramp lesions in patients with anterior cruciate ligament tears. The semimembranosus muscle is a reliable landmark for this technique. The examination position is prone, with the knee joint flexed to 70°. The most important part of this technique is to instruct the patient to perform isometric contractions in knee flexion with the support of an assistant. The presence or absence of a meniscal ramp lesion can be diagnosed preoperatively by setting the probe above the semimembranosus tendon.

Ramp Lesion Subtypes: Prevalence, Imaging, and Arthroscopic Findings in 2156 Anterior Cruciate Ligament Reconstructions

BACKGROUND

Ramp lesions are defined as a particular type of injury within the posterior horn of the medial meniscus and its meniscocapsular attachments. Five subtypes have been described: type 1, meniscocapsular lesion; type 2, partial superior lesion; type 3, partial inferior lesion or hidden type; type 4, complete tear in the red zone; and type 5, complete double tear.

PURPOSE

(1) To determine the prevalence of different subtypes of ramp lesions in patients undergoing arthroscopic anterior cruciate ligament reconstruction (ACLR). (2) To describe the characteristics of ramp lesions based on imaging and diagnostic arthroscopy.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

All patients who underwent arthroscopic ACLRs between November 2015 and November 2018 by 2 senior surgeons at 1 institution were evaluated retrospectively (1) to describe the subtypes of ramp lesions diagnosed intraoperatively using transnotch arthroscopic exploration of the posteromedial compartment and (2) to look for any factors significantly associated with these subtypes. The following parameters were studied: demographics; history and clinical findings including time between injury and surgery, side-to-side laxity, and pivot shift; lesions missed on magnetic resonance imaging (MRI) scans and medial proximal tibial bone contusion visible on MRI scans; and arthroscopic confirmation of ramp lesion (ie, prevalence), associated lateral meniscal tear, or medial chondral tear.

RESULTS

Out of 2156 primary or revision arthroscopic reconstructions, 334 ramp lesions were confirmed, giving a prevalence of 15.5%. The subtype distribution was as follows: type 1, 47.9%; type 2, 4.8%; type 3, 11.4%; type 4, 28.7%; type 5, 7.2%. Multivariate analysis showed that gross pivot shift was significantly associated with complete ramp tears (odds ratio, 4.8; 95% CI, 1.7-17.2). Hidden lesions (type 3, inferior partial tear in the red zone) were the most likely to be missed on preoperative MRI (45.9%).

CONCLUSION

In a population undergoing ACLR, the prevalence of ramp lesions was 15.5%. Among the subtypes of ramp lesion, the most common was a meniscocapsular junction tear (type 1). Partial inferior tears (type 3) were the most likely to be missed on preoperative MRI scans. Gross pivot shift was significantly associated with complete ramp tears (types 1, 4, and 5).

Ramp lesion of the medial meniscus

Ramp lesion of the medial meniscus used to be completely disregarded in the past.

Ramp lesion has been now put under the spotlight by orthopaedic and sport medicine surgeons and requires attention.

It is closely associated with anterior cruciate ligament injury. Major risk factors include chronic laxity, lateral meniscal lesion, anterior cruciate ligament reconstruction revision, anterolateral ligament tear concomitant with anterior cruciate ligament injury, time from injury, pre-operative side-to-side laxity > 6 mm, age < 30 years old, male sex, etc.

Radiologists attempt to create diagnostic criteria for ramp lesion using magnetic resonance imaging. However, the only definite method to diagnose ramp lesion is still arthroscopy. Various techniques exist, among which posteromedial approach is the most highly recommended.

Various treatment options are available. The success rate of ramp repair is very high. Major complications are uncommon.

Cite this article: EFORT Open Rev 2021;6:372-379. DOI: 10.1302/2058-5241.6.200126

Meniscal ramp lesions: frequency, natural history, and the effect on knee cartilage over 2 years in subjects with anterior cruciate ligament tears

PURPOSE

(i) To investigate the frequency and natural evolution of meniscal ramp lesions (MRLs) on MRI in subjects with acute ACL tear and (ii) to compare knee cartilage compositional degeneration between subjects with MRLs and subjects without meniscal pathology over 2 years.

MATERIALS AND METHODS

Fifty-seven subjects with ACL tears (32 females; age 32.6 ± 8.3 years; BMI 24.5 ± 3.5 kg/m²) from a prospective study were screened for the presence of MRLs. Morphological (high-resolution 3D fast spin-echo) and compositional (T1ρ and T2 mapping) MRI was performed prior to and 2 years after ACL reconstruction. Follow-up MR images were assessed for changes in the signal intensity of the MRLs and the presence of meniscal tears. Differences of compositional parameters were compared between subjects with MRLs and without meniscal lesions using independent samples t tests.

RESULTS

MRLs were found in 16% (9/56) of the subjects with ACL tears at baseline. Only one subject with MRLs developed a posterior horn meniscal tear over 2 years. In 12 knees, no meniscal tears were found, which were defined as controls. Most interestingly, cartilage ∆T1ρ of the medial femur and medial tibia increased significantly more in subjects with MRLs compared with controls (mean difference, MF = 6.0 ± 0.8 vs. 2.3 ± 0.6, p = 0.004, and MT = 4.4 ± 1.4 vs. 0.4 ± 0.6, p = 0.027) and medial femur ∆T2 over 2 years increased significantly more in MRL than in control knees (5.1 ± 2.5 ms vs. 2.2 ± 1.9 ms, p = 0.012).

CONCLUSION

Subjects with ACL tear presented MRLs in 16% of cases. Compared with controls without meniscal lesions, knees with MRLs demonstrated accelerated degeneration of cartilage composition in the medial knee compartment over 2 years.

What Is the Relationship Between the Distal Semimembranosus Tendon and the Medial Meniscus? A Gross and Microscopic Analysis From the SANTI Study Group

BACKGROUND

Some authors have suggested that the semimembranosus tendon is involved in the pathophysiology of ramp lesions. This led us to conduct a gross and microscopic analysis of the posterior horn of the medial meniscus and the structures inserted on it.

HYPOTHESIS

(1) The semimembranosus tendon has a tendinous branch inserting into the posterior horn of the medial meniscus, and (2) the meniscotibial ligament is inserted on the posteroinferior edge of the medial meniscus.

STUDY DESIGN

Descriptive laboratory study.

METHODS

In total, 14 fresh cadaveric knees were dissected. From each cadaveric donor, a stable anatomic specimen was harvested en bloc, including the medial femoral condyle, medial tibial plateau, whole medial meniscus, cruciate ligaments, joint capsule, and distal insertion of the semimembranosus tendon. The harvested blocks were cut along the sagittal plane to isolate the distal insertion of the semimembranosus tendon on the posterior joint capsule and the posterior horn of the medial meniscus in a single slice. Histological slides were made from these samples and analyzed under a microscope.

RESULTS

In all knees, gross examination revealed a direct branch of the semimembranosus and a tendinous capsular branch ending behind the posterior horn of the medial meniscus. This capsular branch protruded over the joint capsule, over the meniscotibial ligament below and the meniscocapsular ligament above, but never ended directly in the meniscal tissue. The capsular branch was 14.3 ± 4.4 mm long (mean ± SD). The direct tendon inserted 11 ± 2.8 mm below the articular surface of the tibial plateau. The meniscotibial ligament inserted on the posteroinferior edge of the medial meniscus, and the meniscocapsular ligament insertion was on its posterosuperior edge. Highly vascularized adipose tissue was found, delimited by the posterior horn of the medial meniscus, meniscotibial ligament, meniscocapsular ligament, and capsular branch of the semimembranosus tendon.

CONCLUSION

In all knees, our study found a capsular branch of the semimembranosus tendon inserted behind the medial meniscus. The meniscotibial ligament was inserted on the posteroinferior edge of the medial meniscus. Histological analysis of this area revealed that this ligament inserted differently from the insertion previously described in the literature.

CLINICAL RELEVANCE

This laboratory study provides insight into the pathophysiology of ramp lesions frequently associated with anterior cruciate ligament injury. To restore anatomy, it is mandatory to reestablish meniscotibial ligament continuity in ramp repairs.

Diagnostic performance of open MRI in the flexed knee position for the detection of medial meniscus ramp lesions

OBJECTIVES

To identify the diagnostic performance of magnetic resonance imaging (MRI) in the knee-flexed position for the detection of meniscal ramp lesions in patients with anterior cruciate ligament tears.

MATERIALS AND METHODS

Forty-three patients (mean age 24.5 ± 9.5 years; 21 males, 22 females) with an arthroscopically proven anterior cruciate ligament tear were included in this retrospective study. The presence of the following two important features on MRI was recorded: irregularity of the medial meniscus at the posterior margin, and complete fluid filling between the posterior horn of the medial meniscus and the capsule margin. Findings obtained in arthroscopy served as the reference standard. The diagnostic sensitivity, specificity, and inter-observer agreement were calculated.

RESULTS

Sixteen ramp lesions were noted on arthroscopy (37.2%). With an irregularity of the medial meniscus at the posterior margin on MRI, the sensitivity and specificity were 87.5 and 59.3% at 10° knee flexion and 93.8 and 85.2% at 90° flexion, respectively. The complete fluid filling sign on MRI showed sensitivity and specificity of 31.3 and 100% at 10° knee flexion and 87.5 and 100% at 90° flexion, respectively. The concordance between the two observers for the two MRI features was very good (k = 0.70-0.88).

CONCLUSION

MRI with the knee in the flexed position improves the diagnostic performance of the detection of meniscal ramp lesions compared with MRI with the knee in the extended position.

Surgical treatment of complex meniscus tear and disease: state of the art

The meniscus is important for load distribution, shock absorption and stability of the knee joint. Meniscus injury or meniscectomy results in decreased function of the meniscus and increased risk of knee osteoarthritis. To preserve the meniscal functions, meniscal repair should be considered as the first option for meniscus injury. Although reoperation rates are higher after meniscal repair compared with arthroscopic partial meniscectomy, long-term follow-up of meniscal repair demonstrated better clinical outcomes and less severe degenerative changes of osteoarthritis compared with partial meniscectomy. In the past, the indication of a meniscal repair was limited both because of technical reasons and due to the localised vascularity of the meniscus. Meanwhile, it spreads today as the development of the concept to preserve the meniscus and the improvement of meniscal repair techniques. Longitudinal vertical tears in the peripheral third are considered the 'gold standard' indication in terms of meniscus healing. Techniques for meniscal repair include 'inside-out', 'outside-in' and 'all-inside' strategies. Surgical decision-making depends on the type, size and location of the meniscus injury. Meniscal root tears substantially affect meniscal hoop function and accelerate cartilage degeneration; therefore, meniscus root repair is necessary to prevent the progression of osteoarthritis change. For symptomatic meniscus defects after meniscectomy, transplantation of allograft or collagen meniscus implant may be indicated, and acceptable clinical results have been obtained. Recently, meniscus extrusion has attracted attention due to increased interest in early osteoarthritis. The centralisation techniques have been proposed to reduce the meniscus extrusion by suturing the meniscus-capsule complex to the edge of the tibial plateau. Long-term clinical outcomes of this procedure may change the strategy of treating meniscus extrusion. When malalignment of the lower leg is accompanied with meniscus pathologies, knee osteotomies are a reasonable option to protect the repaired meniscus by unloading the pathological compartment. Advancements in biological augmentation such as bone marrow stimulation, fibrin clot, platelet-rich plasma, stem cell therapy and scaffolds have also expanded the indications for meniscus surgery. In summary, improved repair techniques and biological augmentation have made meniscus repair more appealing to treat that had previously been considered irreparable. However, further research would be necessary to validate the efficacy of these specialised technique.

MRI appearance of the different meniscal ramp lesion types, with clinical and arthroscopic correlation

BACKGROUND

Meniscal ramp lesions have been defined as longitudinal vertical peripheral tears of the medial meniscus involving the posterior meniscocapsular ligament, meniscotibial ligament, and/or the red-red zone of the posterior horn. They are heavily associated with anterior cruciate ligament injuries, and because of their potentially important biomechanical role in knee stabilization, injuries to this region may require surgical repair. However, due to their location and lack of general knowledge regarding their different types and associated appearances on magnetic resonance imaging, ramp lesions are routinely underreported. This is compounded by the fact that ramp lesions are also often overlooked during conventional anterior portal arthroscopy when direct visualization is not achieved.

PURPOSE

To demonstrate MRI appearances and arthroscopic findings of the different types of meniscal ramp lesions, in the hopes of improving their detection on pre-operative imaging.