Meniscal ramp lesions: diagnostic performance of MRI with arthroscopy as reference standard

Background The posteromedial meniscal region is gaining interest among orthopedic surgeons, as lesions of this area has been reported to be significantly associated with anterior cruciate ligament tears. The current imaging literature is unclear. Purpose To evaluate the diagnostic performance of MR in the detection of meniscal ramp lesions having arthroscopy as reference standard. Materials and methods We retrospectively included 56 patients (mean age of 25 ± 7 years; 14 females) from January to November 2017 with a arthroscopically proved ACL tear and posterior meniscocapsular separation. On preoperative MRI, two radiologists with 13 and 2 years’ experience in musculoskeletal imaging assessed the presence/absence of ramp lesion, meniscotibial ligament lesion, peripheral meniscal lesion, or their combination, bone bruise. Having arthroscopy as reference standard, diagnostic performance of MRI in the evaluation of ramp area lesions was calculated. Cohen’s kappa (k) and Fisher's Exact Test statistics were used. Results Agreement between radiologists ranged from κ = 0.784 (meniscotibial ligament lesions) to κ = 0.918 red–red meniscal lesion. Sensitivities were 97.4% for ramp lesions, 95.8% for meniscotibial ligament lesion, 94.4% for peripheral meniscal lesions; specificities were 88.9%, 81.3%, and 97.4%, respectively; accuracies were 94.6%, 87.5%, and 96.4%, respectively. Agreement between MR and arthroscopy was almost perfect in identification of ramp lesions (κ = 0.871) and red–red zone meniscal lesions (κ = 0.908). The agreement between the two methods was substantial (κ = 0.751) for meniscotibial lesion. No significant association between tibial plateau bone bruise and the different type of lesions was found (κ ≥ 0.004 and p ≥ 0.08). Conclusion MR has high diagnostic performance in meniscal ramp area lesion assessment, with substantial to almost perfect inter-reader agreement.

Macroscopic and microscopic analysis of the structures inserted in the posterior segment of the medial meniscus. How is the semimembranosus tendon involved in ramp lesions?

Objectives: The anatomical description of the posterior segment of the medial meniscus is debatable. The aim of this study was to describe by macroscopic and microscopic analysis the histological nature of the posterior segment of the medial meniscus and the inserted structures (semimembranosus tendon and menisco-tibial ligament) Methods: Fourteen fresh knees were dissected. For each specimen, a stable anatomical piece was taken en bloc, including the medial femoral condyle, the medial tibial condyle, the entire medial meniscus, the cruciate ligaments and the joint capsule, and the distal insertion of the semimembranosus tendon was preserved in its entirety. At this stage, a macroscopic analysis was performed. The blocks were cut along the sagittal plane in order to isolate the distal insertion of the semimembranosus tendon on the posterior joint capsule and the posterior segment of the medial meniscus in the same section. Histological slides were produced from these samples and were microscopically analyzed. Results: In all patients, the macroscopic analysis showed direct semimembranosus tendon expansion and tendinous capsular expansion ending behind the posterior segment of the medial meniscus. It projected onto the joint capsule, on the meniscotibial ligament at the bottom and the meniscocapsular ligament at the top, but never ended directly in the meniscal tissue. On average, the tendon directly inserted 11 ± 2.8 mm below the articular surface of the tibial plateau. The length of the capsular expansion was 14.3 ± 4.4 mm. The meniscotibial ligament was inserted in the posterior-inferior edge of the posterior segment of the medial meniscus and the meniscocapsular ligament in the posterior-superior edge. There was a particularly vascularized adipocyte space delimited by the posterior segment of the medial meniscus, the meniscotibial ligament, the meniscocapsular ligament and the capsular expansion of the semimembranosus tendon. Conclusion: We repeatedly noted capsular expansion of the semimembranosus tendon that inserted behind the medial meniscus. There is an interposing zone between the tendon insertion and the body of the meniscus which creates a fragile zone. The capsular tendon expansion also inserts in the meniscotibial ligaments at the bottom and meniscocapsular ligaments at the top.

Rationale and Surgical Technique of Ramp Lesion Repair Through an Additional Posteromedial Portal

Background: Ramp lesions are longitudinal lesions of the meniscocapsular complex of the posterior horn of the medial meniscus. These lesions are poorly recognized, difficult to diagnose, and require specific arthroscopic exploration. Ramp lesions are typically associated with anterior cruciate ligament rupture and have important biomechanical consequences as they result in increased anterior tibial translation and external rotation. Suture hook repair through the posteromedial portal is safe and provides a high healing rate. Indications: Spontaneous healing of ramp lesions is rarely observed, and repair is indicated for all lesions with the involvement of meniscotibial ligament. The choice of a posteromedial repair technique with vertical suture performed under visual control allows restoration of the continuity of meniscotibial ligament and effective healing of these lesions. Technique Description: Standardized arthroscopic exploration with systematic visualization of the posteromedial compartment using the transnotch technique is a crucial point to diagnose these lesions. The use of transillumination and a needle allows to palpate the lesion with the tip of the needle in case of doubt (hidden lesion) before performing the posteromedial portal safely. By using the transnotch vision and by introducing the instruments through the posteromedial portal, debridement with the shaver and repair with the hook of the lesion are performed under visual control. Vertical repair is performed by taking care to pass the hook through the meniscotibial ligament by perforating the deep face of the capsular portion and anterior portion of the ramp lesion. Similarly, it is recommended not to catch too much meniscal tissue on the anterior margin side to remain in the red zone and not to perforate the meniscus in the avascular zone to avoid secondary lesions caused by the “cheese wire” effect of the sutures in the white zone. Results: This technique has allowed us to reduce our percentage of secondary meniscectomy after ramp lesion repair from 25% using a standard arthroscopic exploration and meniscal repair technique through the anterior portal to 11.3% using a arthroscopic exploration and repair technique through the posteromedial portal at 4 years of follow-up. Discussion/Conclusion: Systematic use of the transnotch vision and repair through the posteromedial portal are recommended for the management of these lesions, which demonstrate serious mechanical and clinical consequences.

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.

Surgical Treatment of Meniscal Extrusion: A Biomechanical Study on the Role of the Medial Meniscotibial Ligaments With Early Clinical Validation

Background: Meniscal extrusion refers to meniscal displacement out of the joint space and over the tibial margin, altering knee mechanics and increasing the risk of osteoarthritis. The meniscotibial ligaments have been shown to have an important role in meniscal stability. However, it remains unclear whether an isolated lesion of the medial meniscotibial ligaments will result in meniscal extrusion and whether repairing the detached ligament will reduce extrusion. Hypothesis: A lesion of the medial meniscotibial ligament will result in meniscal extrusion, and repairing the joint capsule will eliminate the extrusion by returning the meniscus back to its original position. Study Design: Controlled laboratory study. Methods: Fresh-frozen human cadaveric knees (N = 6) were used for biomechanical testing. The test protocol involved 100 flexion-extension cycles. In full extension, meniscal extrusion was measured using ultrasound, in both an otherwise unloaded state and while subjected to a 10-N·m varus load. Each knee was tested in its native condition (baseline), after creating a detachment of the medial meniscotibial ligament, and finally with the joint capsule repaired using 3 knotless SutureTak anchors. We also performed a retrospective review of 15 patients who underwent meniscotibial ligament repair with a minimal follow-up of 5 weeks (mean, 14 weeks; range, 5-35 weeks). Results: During biomechanical testing, the mean absolute meniscal extrusion at baseline was 1.5 ± 0.6 mm. After creation of the meniscotibial ligament lesion, the mean absolute meniscal extrusion was significantly increased (3.4 ± 0.7 mm) ( P < .001). After repair, the extrusion was reduced to 2.1 ± 0.4 mm ( P < .001). Clinically, a reduction in absolute meniscal extrusion of approximately 48% was reached (1.2 ± 0.6 vs 2.4 ± 0.5 mm preoperatively; P < .001). Conclusion: This study indicates that the medial meniscotibial ligaments contribute to meniscal stability as lesions cause the meniscus to extrude and that repair of those ligaments can significantly reduce extrusion. Early clinical results using this meniscotibial ligament repair technique support our biomechanical findings, as a significant reduction in meniscal extrusion was achieved. Clinical Relevance: Our biomechanical findings suggest that repair of medial meniscotibial ligaments reduces meniscal extrusion and clinically may improve meniscal function, with the possible long-term benefit of reducing the risk for osteoarthritis.

Impact of Medial Meniscotibial Ligament Disruption Compared to Peripheral Medial Meniscal Tear on Knee Biomechanics

Medial meniscotibial ligament (MTL) lesions may go unrecognized and untreated and have detrimental impact on knee biomechanics and joint pathology. Therefore, this study was designed to compare the biomechanical impact of midbody MTL disruption to corresponding peripheral medial meniscal (PMM) tears in anterior cruciate ligament (ACL) intact and ACL-deficient cadaveric knees. Cadaveric knees (n = 12; 6 matched pairs) were tested for laxity and ACL strain under anterior, valgus, and external rotation loading at 0, 30, and 90 degree of flexion. Knees were randomly assigned to ACL-intact (n = 6) or ACL-deficient (n = 6) groups. Large midbody MTL disruption or corresponding PMM tears were created (n = 3/group) and knees retested. PMM tears were repaired arthroscopically with inside-out suturing, and MTL lesions were repaired with suture anchors via an open approach. Knees were retested after repair. Biomechanical testing data were compared for statistically significant differences. Large MTL and PMM lesions were associated with significant increases in ACL strain, anterior laxity at 0, 30, and 90 degrees (p = 0.006), valgus laxity (p = 0.0012), and external rotation laxity (p = 0.0003) compared with intact knees. Repair of each lesion restored knee stability and reduced ACL strain to intact levels. In ACL-deficient knees, there was significantly increased anterior, valgus, and external rotation laxity compared with the ACL-intact state and MTL and PMM lesions further increased laxity at all angles. However, differences were not statistically significant and repair of meniscal lesions alone did not restore stability to ACL-deficient knees. These results highlight the need to recognize medial MTL injury and perform an appropriate repair procedure to restore knee stability and protect against excessive ACL strain.

Traumatic Injury of Medial Meniscotibial Ligament – Diagnostics and Conservative Treatment

The paper aims to present diagnostic methods and options of conservative treatment of traumatic injuries of medial meniscotibial ligament (MTL). Ca. 75% of all sport-related injuries pertains to the lower extremity; among those, knee damage the second most frequent, after ankle damage. The anteromedial part is where knee pain occurs most frequently. Knee injuries often lead to damage to ligament structures, including medial meniscotibial ligament, which is rarely reported in the literature. Those ligaments may be damaged when the knee is subject to forces leading to valgity and rotation of the femur, internally, and of the tibia, externally. Damage may be caused in an isolated manner, through overloads and combined microdamage. Medial meniscotibial ligaments are formed by a fibrous layer of the articular capsule and are a part of the deep medial collateral ligament. They run from the medial meniscus to the proximal part of the tibia. An MTL examination consists of three parts: medical interview, physical examination and additional examinations. Due to the structure of MTL, its diagnostics must be expanded by an examination of the anterior cruciate ligament (ACL), medial collateral ligament (MCL) and the medial meniscus. Treatment in the acute condition is carried out according to the PRICE (Protection, Rest, Ice, Compression, Elevation) rules. In the subacute and chronic condition, therapy may be expanded for instance by manual therapy methods, functional training, physical therapy and kinesiology taping.