The current findings indicate that meniscal ramp lesions are more associated with the anterior cruciate ligament (ACL) injuries than determined in the past. Among the two reasons as to why these lesions occur are either;
- A sudden disruption of the meniscotibial ligaments of the posterior horn of the medial meniscus
- A tear of the peripheral attachment of the posterior horn of the medial meniscus
Ramp lesions usually go undiagnosed by a magnetic resonance imaging (MRI) and that is why an arthroscopic evaluation is commonly recommended. There are different forms of ramp lesions which are categorized depending on the tear pattern (partial- or full-thickness tear or those associated with meniscotibial ligament disruption.
According to anterior cruciate ligament (ACL) statistics, up to 62% of ACL tears are associated with meniscal lesions.
Ramp Lesion & Anatomy
At least 51% of the medial tibial plateau is covered by the medial meniscus, which is a semilunar fibrocartilage structure. It is broader posteriorly, measuring 11 mm width and toward the anterior meniscal root, it becomes narrower anteriorly. The anterior and the posterior roots connect the meniscus to the tibial plateau. The body of the meniscus is joined to the adjacent joint capsule and also to the tibia by the meniscotibial ligaments.
The joining is crucial for kinematics and injury patterns of the medial meniscus. This is because the tibial and femoral attachments in the posteromedial aspect of the medial meniscus facilitate less mobility when compared to the lateral meniscus.
Therefore, due to the reduced mobility of the medial meniscus, there is an increased risk of injuries, most commonly in deep flexion and with rotational trauma. This generally occurs when the pressure in the posterior horn of the medial meniscus is increased.
However, although more insight into the tears near the posterior aspect of the medial meniscus is made and there is an increased level of awareness, the definite anatomic description of meniscal ramp lesions remains difficult to understand.
Biomechanics & Meniscal Ramp Lesions- Findings
Biomechanics studies have helped illustrate the significance of the menisci because they facilitate load transmission and distribution. In addition to this, they also contribute to cartilage nutrition, proprioception, joint lubrication, and stabilize the anatomical structure.
According to a report, deficiency of the medial meniscus is associated with ACLR failure. Doctors also stress that it is currently unclear whether the lesions affect joint kinematics and loading in the medial. But, ramp lesions have been identified to increase forces on the ACL. In the same way, lesions of the meniscotibial ligaments may also trigger an increase in the rotatory instability of the knee.
Although MRI is an effective diagnostic technique in orthopaedics, an arthroscopy is necessary to diagnose ramp lesions. MRI’s findings of a ramp lesion are normally a thin fluid signal which is located between the posterior horn of the medial meniscus and the posteromedial capsule. Other barriers like an incomplete fluid filling adjacent to the peripheral edge of the meniscus may make the detection of the ramp lesions difficult.
Although surgical repair approaches can be utilized to repair or treat ramp lesions, non-surgical treatments can also be utilized for the same. Surgical approaches include inside-out meniscal repair or all-inside meniscal repair. In case there is an isolated ramp lesion, a standard meniscal repair rehabilitation procedure must be utilized.
On the other hand, in case a concomitant ACL reconstruction (ACLR) is performed, rehabilitation must follow the designated ACLR postoperative procedure.
During the surgery, the patient is made to lie down while facing the ceiling on the operating table. Following that, the tourniquet is placed high on the thigh and the knee at 90° of flexion. A foot support to facilitate a full range of knee motion is used. A standard high lateral parapatellar portal and a medial parapatellar portal for the arthroscope and instruments are used respectively.
Goals for surgical repair include knee range of motion, edema control, and quadriceps-activation exercises. The major focus is extended to prevent weight bearing and joint compressive forces.