Ramped Up

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.

Meniscal Ramp Lesions: What the Radiologist Needs to Know

Meniscal ramp lesions are a special type of injury that affects the periphery of the posterior horn of the medial meniscus (PHMM) and/or its meniscocapsular attachments. They are strongly associated with acute and chronic anterior cruciate ligament (ACL) tears. These lesions have gained much prominence in recent years, due to a significant increase in their diagnosis and their important biomechanical involvement in the knee. It is known that their presence in ACL-deficient knees is related to instability and if they are not repaired during ACL reconstruction, they can ultimately cause the failure of the graft. Since this type of injury is often underdiagnosed due to its localization at the "blind" point of arthroscopic vision, it is crucial to make an accurate preoperative diagnosis of them with MRI. The objective of this article is to review the recent literature regarding meniscal ramp lesions and to summarize the anatomical, biomechanical and fundamentally diagnostic aspects, emphasizing the radiological findings described until now.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

Diagnostic study, Level III.

Isolated Meniscal Ramp Lesion Without Obvious Anterior Cruicate Ligament Rupture

OBJECTIVES

The purpose of the present paper was to study isolated meniscal ramp lesions without obvious ACL rupture. Their biomechanical mechanisms were analyzed and their clinical characteristics were reviewed. The clinical effects of an all-inside horizontal mattress suture for isolated ramp lesions were evaluated.

MATERIALS AND METHODS

Twenty isolated meniscal ramp lesion patients without obvious ACL rupture from 2015 to 2017 were retrospectively reviewed. Preoperative MRI showed intact ACL and signs of ramp lesions. These isolated ramp lesions were arthroscopically confirmed and repaired through an all-inside horizontal mattress suturing method. MRI was performed 3 months postoperatively to assess isolated ramp lesion healing. The Tegner-Lysholm score and the visual analog scale score were recorded preoperatively and at 2 years postoperatively. The Wilcoxon rank sum test was performed to determine statistical significance.

RESULTS

Arthroscopic exploration confirmed isolated ramp lesions and longitudinal ACL splits or degeneration without obvious ACL rupture. MRI 3 months postoperatively showed healing of the isolated ramp lesions. At 2 years postoperatively, the VAS scores were significantly decreased and the Tegner-Lysholm scores were significantly increased. Knee function, without pain, was restored in all patients, including walking, climing and descending stairs, and squatting.

CONCLUSION

Isolated meniscal ramp lesions without obvious ACL rupture may exist because of ACL longitudinal splits or degeneration and can be repaired through anterolateral and anteromedial portals with an all-inside horizontal-mattress suturing method.

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.

Meniscal ramp lesions should be considered in anterior cruciate ligament-injured knees, especially with larger instability or longer delay before surgery

PURPOSE

To determine the incidence of meniscal ramp lesions in an anterior cruciate ligament (ACL) injured knees and to clarify whether ramp lesions are related to chronic ACL deficiency and increased knee instability.

METHODS

Consecutive ACL injured patients were evaluated arthroscopically for a ramp lesion via a trans-notch view and evidence of menisco-capsular injury was recorded. Other concomitant injuries to the knee were also noted. Incidence of meniscal ramp lesions, delay before surgery, and anterior-posterior stability was analyzed. All patients underwent bilateral KT-2000 evaluation.

RESULTS

One hundred and three consecutive ACL injured patients with a mean age of 24 years were included in this study. In total, a ramp lesion was found in 10 knees (9.7%) via a trans-notch view. None of these lesions could be identified by the standard view from the anterolateral portal. Other medial meniscal lesions were found in 26 knees (25.2%) by standard arthroscopic viewing. The ramp lesion group had significantly longer delay before surgery with a median of 191 days (p < 0.01) as well as a larger side-to-side difference of KT-2000 measurement (7.3 ± 1.8 mm; p < 0.01), compared with the intact medial meniscus group (53 days and 5.5 ± 1.5 mm, respectively).

CONCLUSION

Ramp lesions that were identified using a trans-notch view were not visualized with standard arthroscopic views. Increased anterior tibial translation and longer delay before surgery were seen in knees with ramp lesions. Careful inspection of the posteromedial menisco-capsular region is required as hidden menisco-capsular lesions may occur which may result in residual knee instability.

LEVEL OF EVIDENCE

Level II.

Ramp lesions: a systematic review of MRI diagnostic accuracy and treatment efficacy

Purpose

We conducted a systematic review of the published literature to assess the accuracy of Magnetic Resonance Imaging (MRI) in establishing the presence of ramp lesions (RLs) in Anterior Cruciate Ligament (ACL) deficient knees and the clinical efficacy of the surgical repair of RLs.

Methods

A comprehensive search of the MEDLINE, Web of Science and Scopus databases was performed according to PRISMA guidelines. Studies assessing MRI diagnostic accuracy for RLs or the clinical effect of RL repair in participants with ACL injuries were included. Diagnostic accuracy measures were pooled and plotted in forest plots. Preoperative and at last follow-up treatment efficacy outcome measures were extracted and plotted in forest plots, for graphical comprehension.

Results

Sixteen studies met the criteria and were included. The diagnostic analysis showed a pooled sensitivity, specificity, positive and negative likelihood ratios of 65.1% (95% CI, 59.73 to 70.42), 91.6% (95% CI, 89.14 to 94.05), 2.91 (95% CI, 2.38–3.55) and 0.53 (95% CI, 0.44–0.64), respectively, with high heterogeneity (I² above 80%) for all measures. Treatment analysis showed improved Lysholm Knee Score, IKDC score and laxity difference between the knees in all studies after meniscal suture repair. A separate analysis showed no differences between repair of smaller, stable, RLs with meniscal sutures and repair with abrasion and trephination only.

Conclusion

Although the results present considerable heterogeneity, MRI seems to demonstrate moderate accuracy in the diagnosis of RLs in patients with ACL tear and the surgical repair of RLs can be associated with improved overall outcomes.

Ramp Lesions: An Unrecognized Posteromedial Instability?

Meniscal ramp lesions occur much more frequently than was previously considered, and particularly so in ACL-injured knees. The historically high rate of missed diagnoses is a result of unfamiliarity with this injury pattern within the orthopedic community, and also the difficulty in diagnosis. A systematic exploration of the posteromedial compartment of the knee is mandatory to reliably identify ramp lesions. Failure to recognize and repair these injuries is associated with persistent anterior and posteromedial instability. Understanding their nature, biomechanics, and epidemiology is essential in allowing orthopedic surgeons to suspect their presence and adequately treat these lesions.

Effect of Meniscal Ramp Lesion Repair on Knee Kinematics, Bony Contact Forces, and In Situ Forces in the Anterior Cruciate Ligament

BACKGROUND

Meniscal ramp lesions are possible concomitant injuries in cases of anterior cruciate ligament (ACL) deficiency. Although recent studies have investigated the influence of ramp lesions on knee kinematics, the effect on the ACL reconstruction graft remains unknown.

PURPOSE/HYPOTHESIS

The purpose was to determine the effects of ramp lesion and ramp lesion repair on knee kinematics, the in situ forces in the ACL, and bony contact forces. It was hypothesized that ramp lesions will significantly increase in situ forces in the native ACL and bony contact forces and that ramp lesion repair will restore these conditions comparably with those forces of the intact knee.

STUDY DESIGN

Controlled laboratory study.

METHODS

Investigators tested 9 human cadaveric knee specimens using a 6 degrees of freedom robotic testing system. The knee was continuously flexed from full extension to 90° while the following loads were applied: (1) 90-N anterior load, (2) 5 N·m of external-rotation torque, (3) 134-N anterior load + 200-N compression load, (4) 4 N·m of external-rotation torque + 200-N compression load, and (5) 4 N·m of internal-rotation torque + 200-N compression load. Loading conditions were applied to the intact knee, a knee with an arthroscopically induced 25-mm ramp lesion, and a knee with an all-inside repaired ramp lesion. In situ forces in the ACL, bony contact forces in the medial compartment, and bony contact forces in the lateral compartment were quantified.

RESULTS

In response to all loading conditions, no differences were found with respect to kinematics, in situ forces in the ACL, and bony contact forces between intact knees and knees with a ramp lesion. However, compared with intact knees, knees with a ramp lesion repair had significantly reduced anterior translation at flexion angles from full extension to 40° in response to a 90-N anterior load (P < .05). In addition, a significant decrease in the in situ forces in the ACL after ramp repair was detected only for higher flexion angles when 4 N·m of external-rotation torque combined with a 200-N compression load (P < .05) and 4 N·m of internal-rotation torque combined with a 200-N compression load were applied (P < .05).

CONCLUSION

In this biomechanical study, ramp lesions did not significantly affect knee biomechanics at the time of surgery.

CLINICAL RELEVANCE

From a biomechanical time-zero perspective, the indications for ramp lesion repair may be limited.

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

BACKGROUND

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

PURPOSE

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

STUDY DESIGN

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

METHODS

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

RESULTS

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

CONCLUSION

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