Knee is the biggest and most complicated joint in the body:
It is a joint between the femur, tibia and patella. The patella is an associated bone which is located in the tendon of the quadriceps muscle of the thigh. The function of the knee is to enable mobility, but also to hold the body's weight and to transfer it to the feet during walking. The joint facets of the femur are convex, while the tibia's are mostly flat.
This way, the mobility of the knee is enhanced, but so is stability reduced. To improve the stability of the knee and make the transferred weight to the tibia as little as possible, it is necessary for the joint facets to be bigger and complement each other. This is why there is a strong emphasis on the function of the stabilizers of the knee joint. We divide the stabilizers into active and passive. Active stabilizers are muscles which move the joint.
Passive stabilizers are ligaments, joint surface and menisci. The most important ligaments of the knee are the anterior and posterior cruciate ligament, as well as the medial and lateral collateral ligament. The patella is stabilized by the patellar ligament and the medial and lateral retinaculum. The menisci are fibrocartilaginous lunate structures.
The medial and lateral meniscus in the knee. The menisci have important functions in the knee joint. They reduce the discrepancy of the joint facets with which they ensure equal distribution of force. They participate in spreading of the synovial fluid and have a task of being elastic „ shock absorbers“, thus preventing consequent injuries. During various movements in the joint, they move either forward or backward. This way, the menisci enable the sliding of the joint facets and avoid being crushed between the bones.
The menisci take on about 50% of the load which is transferred through the extended knee joint and around 85% of the flexed knee. The movement in the knee can injure the menisci. The characteristic injury mechanism is rotation and flexion off the thigh in comparison to the tibia stabilized on the surface. These are usually quick and sudden actions when the active stabilizers do not manage to stabilize the knee and the joint facets put bug pressure on the meniscus itself. During these types of movements, the patients usually complain that something hurt them or burnt them on the inner or outer side of the knee.
The knee can remain blocked if the damaged menisci stops the sliding of the joint facets. Usually within 24 hours of injury, swelling of the knee occurs. The injuries diagnosed with the clinical examination and magnetic resonance if necessary. If the meniscus is not trapped between joint facets, the treatment can begin non-surgically which includes physical therapy, reducing the load and drugs to reduce pain. Surgical procedures depend on the type and size of damage, place of damage and patient age.
The surgery is done arthroscopically and should be as sparing as possible. This case is the damaged part of the meniscus is removed which is called meniscectomy. In case of a partial or total trapping of the meniscus, the contact surface reduces and the load increases. Partial meniscectomy (only 10% of the meniscal surface) results in 65% increase of the load on the point of contact. For that reason, we prefer suturing the meniscus whenever possible. Unfortunately, less than 25% of injuries are eligible for suturing.
The best places to suture are small, fresh horizontal tears located on the part of the meniscus next to the joint surface in younger people, and especially if they are done together with the reconstruction of the anterior cruciate ligament. Meniscal suturing is a technically difficult procedure which prolongs the surgery, and requires the knowledge of a few different suturing techniques and special surgical instrumentation.