Abstract
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.
This is a visual representation of the abstract.
Video Transcript
Posteromedial compartment exploration is mandatory to identify hidden lesion. Spontaneous healing of the stable tear is not proven. All-inside repair with a suture hook improves the healing rate. Ramp lesion occurs during anterior cruciate ligament (ACL) rupture due to the crushing mechanism of the posterior horn of the medial meniscus between the femoral condyle and the tibial plateau and probably worsens by the reflex contraction phenomenon of the semimenbranosus. The posterior horn of the median meniscus is firmly attached to the tibia by the meniscotibial ligament which is torn in most of the ramp lesions. The extension of the lesion toward the posterior horn of the meniscus should also be considered to identify unstable tear.
Ramp lesions are often missed on preoperative magnetic resonance imaging (MRI), probably because this area is difficult to explore, and the MRI is performed with the knee in full extension. Some of them have a spontaneous healing potential as seen on these 2 examples. But not all ramp lesions do, and Sonnery-Cottet have recently shown that the longer the delay between the injury and the surgery, the more frequently chronic ramp lesion tears occur.
The patient is positioned in supine with the knee bent at 90°. The first step of the procedure is the exploration with anterior probing of the posterior horn of the medial meniscus. Then, a transnotch visualization is performed by pushing the scope deep in the notch between the triangle formed by the condyle, the tibial spine, and the posterior cruciate ligament. When the knee is bent at 90°, the posteromedial bundle of the posterior cruciate ligament is relaxed and makes this procedure easier. Transillumination helps to place the needle in the safe zone and to avoid any vascular injury.
We have described 5 subtypes of ramp lesion:
• Type 1 is a very peripheral lesion. Both ligaments are disrupted as you can see in this example where the tibial plateau is seen underneath the tear.
• Type 2 is a partial superior lesion without any tear of the meniscotibial ligament. This tear is believed to be stable.
• Type 3 is a hidden lesion; the meniscotibial ligament is torn, and this tear is unstable when we test the mobility of the posterior horn of the medial meniscus with the hook. Sometimes, there is a thick layer superficial which needs to be debrided with the shaver. In the second example, it is easy to bring the meniscus under the condyle, which is a sign of instability, and the layer on the superficial aspect of the medial meniscus is very thin and easily debrided with the needle.
• Type 4 is a complete tear in the red zone. The outer portion of the lesion is constituted by meniscal tissue.
• Type 5, which is less frequent, is a double tear, which has been described for the first time by Ahn et al.
We advocate to perform a posteromedial portal which must be performed not too close to the femoral condyle to easily manipulate the suture hook. This portal allows to perform a debridement of the tear and a freshening of the lesion (Figure 1). Positioning the foot in internal rotation will facilitate the visualization by translating the medial tibial plateau posteriorly. A 25° left curved suture hook will be used for the right knee. First, the hook penetrates through the outer portion of the meniscus and then through the inner portion. Then the suture is retrieved from the posteromedial portal and a standard sliding knot is performed. Be aware of placing the knot on the capsular side rather than on the meniscus side. It is possible to perform multiple stitches with a single suture hook. This patient had a 2-step procedure: first, meniscal suture was performed, and then 6 weeks later, the ACL was reconstructed. As you can see, the ramp lesion is completely healed 45 days after the suture.
Palpation of a ramp lesion through an additional posteromedial portal.
Potential Complication: One typical mistake is to try to grab too much meniscal tissue of the inner portion of the meniscus. This will create a cleft in the white area of the meniscus, and this cleft is probably one of the most common causes of failure of meniscal suture because of the cheese wire mechanism. This is the main issue that is encountered when trying to fix a ramp lesion with an all-inside suture implant. As you can see in this example, the anchor is correctly positioned and flipped, and it is possible to grab the meniscotibial ligament, but this is an example 6 months after the failure, and as you can see, the cleft left in the meniscal tissue by the meniscal implant will create a newly formed tear which is located more anteriorly than the previous tear. This is a typical example of a meniscal flap which is a failure of meniscal suture of a ramp lesion. With transnotch visualization, we can see the stitches are still there; the ramp lesion is perfectly healed, but the stitches have created a newly formed anterior tear. The postoperative protocol and return to sport criteria are strictly identical when compared with a standard ACL reconstruction; all patients are allowed to bear weight as tolerated; physical therapy starts 24 hours after the surgery. Gradual return to play is initiated at the 6-month follow-up. Return to sports or activity is allowed when the patient achieved normal strength, stability, and knee range of motion comparable with the contralateral side.
Patient Outcomes: The secondary meniscectomy rate dropped from 25% when all-inside suture implants are used to 14% at more than 4 years of follow-up without any anterolateral ligament (ALL) reconstruction and less than 7% when a combined ACL and ALL reconstruction is performed.
Footnotes
Submitted December 23, 2020; accepted January 21, 2021.
One or more of the authors has declared the following potential conflict of interest or source of funding: M.T. and J.M.F. are paid consultants for Arthrex. B.S.C. is a paid consultant and receives royalties from Arthrex. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.
