Causes of meniscus injury
1, meniscus injury is mostly caused by torsional force, the meniscus in the knee joint between the femoral condyle and tibia, by the rotational pressure, and the meniscus tears.
Many patients have no obvious history of trauma or sprain, but gradually develop knee pain, initially painful when walking up or down stairs, and later painful when walking on a flat road, or even joint locking “stuck”, which is slowly relieved by stopping to rest, and then continuing to walk.
Location of the meniscus (medical anatomy)
The meniscus is two crescent-shaped fibrocartilages located on the medial and lateral articular surfaces of the tibial plateau. Its cross-section is triangular in shape, thick on the outside and thin on the inside, slightly concave on top so as to coincide with the femoral condyles, and flat on the bottom, where it meets the tibial plateau. Such a structure precisely allows the femoral condyles to form a deeper depression in the tibial plateau, which results in increased stability of the spherical femoral condyles to the tibial plateau.
The marginal part of the meniscus is thick and tightly attached to the joint capsule, while the central part is thin and free. The medial meniscus is “C” shaped and the lateral meniscus is “O” shaped. The meniscus is a kind of fibrocartilage, which has no blood supply itself, and its nutrition mainly comes from synovial fluid, only the side part connected with the joint capsule gets some blood supply from synovial membrane.
The role of the meniscus
Simply put, the function of the meniscus is to stabilize the knee joint, to transmit load to the knee joint, and to promote intra-articular nutrition. It is the stabilizing effect of the meniscus that ensures that the knee joint is not damaged by years of weight-bearing exercise.
1. Weight-bearing
When not bearing weight, the tibia and femur are not in contact and the meniscus pads between them. When weight-bearing, about 70% of the weight-bearing area is on the meniscus, which greatly reduces the stress on the tibial plateau, thus protecting the cartilage and the whole joint. If the meniscus is removed, the peak pressure on the tibial plateau can rise twofold and will cause cartilage degeneration. It can be inferred that in the case of transverse meniscal tears, the weight-bearing function of the meniscus is completely lost. This requires us to cut as little as possible during partial meniscectomy.
Maintenance of knee joint motion coordination
The meniscus moves together with the tibia, the medial meniscus is less displaced than the lateral meniscus, and the meniscus can be deformed during knee flexion and extension to accommodate the anatomical shape of the knee joint. This maintains the coordination of the geometry of the knee joint, thus maintaining the coordination of knee motion.
2. Maintaining stability
Meniscectomy does not cause anterior tibial displacement when the ACL is intact, whereas it causes greater anterior tibial displacement when the ACL is ruptured.
3. Absorption of concussion
There are such patients with knee pain whose arthroscopic pathology did not reveal any abnormality, while their symptoms were obvious, and later found to have poor meniscus absorption after examination.
4. Lubricating joints
In addition, the meniscus has the function of lubricating the joint, etc. The meniscus can evenly coat the joint surface with joint fluid, so that the friction coefficient of the joint is greatly reduced.
Diagnosis
The pressure pain at the knee joint gap is an important basis for meniscus injury.
1. The purpose of radiographs is not to diagnose meniscal tears, but to rule out osteochondral free bodies, exfoliative osteochondritis and other knee disorders that may resemble meniscal tears.
2. MRI is by far the imaging tool with the highest positive sensitivity and accuracy in diagnosing meniscal injuries, cruciate ligament rupture, etc., with an accuracy rate of 98%. MRI of meniscal tears shows a low signal meniscus with linear or complex shaped high signal bands across the surface of the meniscus.
3, arthroscopy Arthroscopic techniques have been recognized as the most ideal means of diagnosis and surgical management of meniscal injuries. However, arthroscopy should not be a routine means of examining meniscal tears. Its superiority can only be demonstrated when arthroscopy is performed to confirm the diagnosis and simultaneous arthroscopic surgical management after the initial clinical diagnosis of a meniscal tear has been made.
Prognosis
The meniscus is a fibrocartilaginous tissue that has no blood supply of its own, so recovery from injury is slow, making treatment very difficult. There are many ways to treat meniscal injuries. Physical therapy and massage can improve local circulation and promote nutrient supply to temporarily relieve symptoms but cannot solve the root cause of the problem. Surgery is traumatic, high-risk, and has many complications that are generally not considered. The medical profession is of the opinion that medicine is not capable of reversing the course of meniscus injury, and patients can only use painkillers, painkilling injections, and closed-loop treatment to relieve symptoms. However, with the recent medical research, such as the study of regenerating meniscal cartilage, this situation has been gradually broken. The meniscus itself is a piece of cartilage, made up of cartilage cells, and because there are no blood vessels in it, for many years the medical community believed that meniscal cartilage could not be regenerated, but it is a fact that as the body grows from a baby to an adult, the human joints grow from small to large, and if they cannot absorb nutrients, where do they get the raw materials they need to grow? Of course joint cartilage can absorb nutrients! The blood vessels deliver nutrients to the joint fluid in the joint cavity, and the meniscal cartilage absorbs nutrients from the joint fluid. In addition, there are other ways of absorbing nutrients through the adjacent tissues, which I will not go into here.
Treatment
1. In the acute stage, if there is obvious fluid (or blood) accumulation in the joint, the fluid should be extracted under strict aseptic operation; if there is “interlocking” of the joint, the “interlocking” should be released by manipulation, and then the knee should be fixed in the straight position with a tubular cast from the upper 1/3 of the thigh down to the ankle. 4 weeks. The cast should be properly shaped so that the patient can walk with the cast on the floor. During the fixation period and after removal of the cast, the quadriceps should be actively exercised to prevent muscle atrophy.
2, meniscal blood supply area injury repair meniscal blood supply area injury, especially the longitudinal laceration, can be healed by suture surgery, the procedure has a good prognosis, which has been confirmed by many experimental and clinical studies. However, in a 10-year prospective study, many patients who underwent such surgery were found to have x-ray signs of joint degeneration, suggesting that the biomechanical function of the repaired meniscus may not have been completely reestablished.
3. Repair of meniscus bloodless zone injuries is relatively difficult and has become a challenge in knee surgery. Smaller and regular injuries to the meniscus without blood supply, such as barrel stem-like tears, are often treated with partial resection with fair results.
If the meniscus is severely damaged, it is only possible to perform a total meniscectomy. At this time, frozen meniscus and meniscal prosthesis transplantation are feasible, but there are many problems with meniscal prosthesis transplantation, such as the biomechanical function of the prosthesis cannot meet the requirements, the prosthesis is difficult to fix, and joint degeneration is still obvious after transplantation.
The usual points to note
1, diet less greasy, high fat, more vegetables and fruits, less fine food, more coarse food.
2.When going up and down the stairs, you must pay full attention and step steadily before moving the second step, in order to avoid trauma.