What is the meniscus?
The meniscus is a crescent-shaped structure formed by fibrocartilage and located in the knee, between the femur and the tibia. Traumatology specialists explain that people have two menisci in each knee, one external and the other internal.
The internal meniscus has a āCā shape and the external meniscus, which is more closed, has almost an āOā shape. Both are composed mostly of type 1 collagen fibers arranged parallel to their major axis, a fact that gives them a great capacity to withstand tensile forces. The menisci are attached to the tibia by means of the anterior and posterior roots. In addition, they are also attached to the joint capsule at its periphery.
The menisci have little cellular density, and only receive contribution of blood vessels in its more peripheral 1/3. For this reason, its healing capacity is limited.
Functions of the meniscus
The main biomechanical function of the meniscus is to assist in the transmission of loads in the knee joint between the femur and the tibia. The two compartments of the femoro-tibial joint, internal and external, are not totally congruent. The tibial plateau is flat and the external compartment is slightly convex. For its part, the surface of the femoral condyles is convex.
This anatomical arrangement makes the menisci necessary to make the joint more congruent, increasing the contact area and thus distributing the weight transmitted through the joint over a larger surface area. This protects the articular cartilage.
Another function of the meniscus is to provide stability to the joint. In this way, patients who undergo reconstruction of the Anterior Cruciate Ligament and have their meniscus repaired have better stability than those who have had their meniscus removed.
What does meniscal tear suturing consist of?
Suturing a meniscal tear consists of repairing the damaged tissue, instead of removing it, which is what was traditionally done. In this way, we maintain the load distribution function of the meniscus and prevent future osteoarthritis. On the contrary, the removal of the meniscus causes that the distribution of loads in the joint is not uniform, decreasing the area of contact when losing the joint of congruence. This causes the loads to be transmitted in a very small area in the contact zone between the femur and the tibia.
For its part, the articular cartilage functions very well as a sliding surface, with a very low friction coefficient, but it is not designed to withstand the very high loads to which it is subjected in the event of meniscus failure, since it begins to degenerate and arthrosis occurs. The latter occurs safely and quickly. The situation is even more delicate in the case of the external meniscus, whose function is more important than that of the internal meniscus. The meniscus must be saved!