1.What is the meniscus?
The meniscus is a “C”-shaped “wedge” of fibrocartilage, or fibrocartilage pad, located between the tibia and femur. There are two pieces in each knee joint, the medial meniscus and the lateral meniscus.
2. What is the role of the meniscus in the knee joint?
The meniscus has the following functions.
① distributing the stresses acting on the cartilage of the articular surface.
② absorbing impact forces.
③Increasing the stability of the joint.
④Joint lubrication, so that the joint fluid is evenly distributed and better nourishes the articular cartilage.
3.What are the causes of meniscus injury?
Typical meniscal tears are related to trauma. The meniscus is usually easily damaged when the foot is fixed and the knee joint is twisted, or when standing suddenly in a squatting position, but there is not a definite history of trauma. Healthy young people usually suffer some degree of trauma to the knee before meniscal tears occur, while in older adults a significant proportion of meniscal tears occur during daily activities or simple movements such as squatting. As we age, meniscal tears become almost a result of degenerative changes.
4.What are the symptoms of discomfort in the knee joint after meniscus injury?
Patients often complain of pain, swelling, locking, “stuck feeling”, “squeezing pain”, and “weak leg” after meniscus injury, and many people experience pain and discomfort going up and down stairs. Many people experience pain and discomfort going up and down stairs, especially down stairs, but it is not specific. Patients often have difficulty describing knee symptoms and can simply express them as “my knee is stuck,” “something is wrong,” or “something keeps misaligning and resetting. In acute injuries, 55% of patients have swollen and fluid-filled joints, and when the injury is prolonged (after a few weeks), there is often thinning of the affected thigh (quadriceps atrophy).
5. What tests are helpful in diagnosing meniscal injuries?
MRI (magnetic resonance imaging) is the imaging method of choice for evaluating meniscal disorders. However, the presence of an abnormal signal on MRI does not indicate a definite meniscal tear, so not all meniscal lesions require surgical treatment. Meniscal injury and degeneration can lead to meniscal MRI signal changes, which are classified as grade 0-III depending on the signal range. Once MRI shows grade III signal within the meniscus, it suggests that the meniscus has torn, and arthroscopic meniscus treatment is needed at this time.
6.What types of meniscal injuries are there? Can it heal on its own?
Meniscus injury is divided into four types: longitudinal tear, transverse tear, horizontal tear and compound tear. The treatment of each type of meniscus injury depends on the blood flow of the meniscus. The distribution of meniscus blood vessels determines whether suture surgery can be performed after meniscus injury. In adults, the meniscus is only vascularized in 10% to 30% of the peripheral rim. The meniscus can be divided into three zones according to its blood supply, namely the red zone, the red-white zone and the white zone. Due to the special anatomy and blood supply characteristics of the meniscus, it is difficult to heal on its own after injury, and different methods are needed to treat different parts of the injury. Red zone tears heal easily after suturing, red-white zone injuries have the possibility of healing after suturing by some special methods, and white zone injuries cannot heal after suturing. The white zone is mainly supplied by the synovial fluid in the joint. Currently, the meniscus is treated by suturing or excision of the torn area whenever possible. Treatment is determined by the location of the meniscus injury: the inner 1/3 of the meniscus (white zone) has no blood flow and usually needs to be resected; the middle 1/3 (red-white zone) has partial blood flow and can heal with sutures; the outer 1/3 (red zone) of the adult meniscus is rich in blood flow and tears in this area often heal spontaneously if they are less than 15 mm, while tears larger than 15 mm need to be sutured. Treatment is determined by the type of meniscal injury: longitudinal tears have a high healing rate after suturing, transverse tears and horizontal tears have a low healing rate after suturing, and compound tears are difficult to heal after suturing, so transverse tears, horizontal tears and compound tears are generally treated by excision of the injury site.
7.Why is it necessary to treat meniscus injury in time? What kind of damage will be caused to the joint without treatment?
Since the meniscus is located between the tibia and the femur in a “C” shape, as long as the lower limb is walking with weight, it will cause grinding and extrusion. If the original tear is treated in time, it may be possible to preserve most of the meniscus function by suturing or partial resection, but if it is allowed to develop, the meniscus can only be completely removed, which will result in a complete loss of meniscus function. The meniscus itself has no blood flow, only circulation at the periphery, so only marginal tears may heal. The torn meniscus not only loses its role in helping to stabilize the joint and protect the articular cartilage, but also interferes with the normal motion of the knee joint and even causes interlocking. Long-term presence can also lead to increased injury, wear and tear of the articular cartilage, osteophytes, synovitis and other pathological changes, i.e. traumatic arthritis. Therefore, early diagnosis of meniscus injury and timely treatment are important.
8.Why should meniscus repair treatment be performed?
Since meniscus has important physiological functions, which can conduct load, absorb shock, reduce stress, improve joint stability, and coordinate and lubricate joints, most people now believe that the functionally intact meniscal tissue should be preserved as much as possible. Therefore, meniscal injuries should be diagnosed and treated early to minimize the chance of total meniscectomy, and the earlier the treatment, the better the results. Unstable meniscus injury should be operated as early as possible, if operated late there will be the following problems.
① The tear will increase, resulting in more meniscus being removed in future surgery. The more meniscus removed, the greater the post-operative impact on the knee joint.
② With an acute meniscus injury, there is an opportunity for suture repair, and the sutured meniscus can still heal and will be similar to an uninjured meniscus. Postponing the surgery will make the suture opportunity lost.
③ Even if the meniscus is completely removed, it will cause less wear and tear on the joint than if the torn meniscus is left in the joint. To prevent accelerated degeneration of the knee joint, early surgery should be performed.
④Early surgery can resume all activities such as life, work, sports or normal training for athletes as soon as possible.
9.What surgical procedures are available for meniscal injuries?
(1) Meniscus suture repair.
(1) Incisional repair.
(2) Arthroscopic-assisted repair from the outside and inside.
(3) Arthroscopic-assisted inside-out and outside-in repair
④Arthroscopic total intra-articular repair. A variety of arthroscopic total internal suturing instruments are available, which are convenient for clinical application. The surgical results are similar to those of incisional surgery, but the surgical safety is significantly improved, and no auxiliary skin incision is required, which significantly reduces trauma.
(2) Arthroscopic meniscectomy: According to the amount of meniscus tissue removed, it is divided into partial resection, subtotal resection and total resection.
(3) Meniscus transplantation: Since meniscectomy has different degrees of adverse effects on the knee joint, allogeneic meniscus transplantation has been carried out and has achieved better clinical results. However, in recent years, only a few hospitals in China have carried out this surgery. Due to the small number of surgical cases and short follow-up time, the long-term efficacy remains to be observed.
10.How to recover from meniscus injury after surgery? How long does it take?
Early postoperative rehabilitation can promote blood circulation and strengthen postoperative meniscus nutrition to facilitate healing and muscle strength recovery, avoiding complications such as muscle atrophy and joint stiffness. The following points should be noted in the rehabilitation exercise process.
① Postoperative body parts other than the operated limb should be practiced as much as possible to ensure physical fitness, improve the overall circulatory metabolic level and promote the recovery of the operated local area.
②Joint mobility (flexion and extension) exercises within 2 weeks after surgery should be performed only once a day, and strive to achieve the required mobility early, avoiding repeated flexion and extension and multiple exercises.
③Ice packs should be applied for 20-30 minutes immediately after the mobility exercises. If you usually feel swelling, pain and heat in the joint, you can apply ice again, 2-3 times a day.
④The exercises should be completed according to the requirements of the rehabilitation program, do not exceed the prescribed angle, and do not fail to reach the prescribed angle.
There are also differences in rehabilitation programs for meniscus injury with different surgical methods.
① For partial or complete meniscus removal, you can walk on the ground 2 days after surgery, and generally wash your face, brush your teeth, go to the bathroom and other daily life can be taken care of by yourself, and you can be competent to sit in the office after 1 week of discharge, and you can participate in sports 2 months after surgery.
For those who have meniscus suture, they need to walk with the aid of crutches within 6 weeks after surgery, the injured limb should not bear weight too early, and the bending knee angle should not exceed 90° within 4 weeks, and they should not do complete squatting within 3 months to avoid affecting the healing of the sutured meniscus, and it is better to participate in strenuous sports after half a year.
11.Is there any sequelae of meniscus surgery?
Arthroscopy is a minimally invasive surgical method, which is an important symbol of the current medical development, with less trauma, faster recovery, and significantly less sequelae and complications. There are concerns that there may be sequelae after meniscal surgery. In fact, with experience, arthroscopic surgery itself does not cause damage to the knee joint. If there are sequelae, they are related to the location and extent of meniscal damage. If the meniscus is damaged in the white zone, only a local repair can be done, and the postoperative effect on the joint is small; if it is a longitudinal tear in the red zone or red-white zone of the meniscus, the tear can be sutured, so that most of the meniscus can be preserved, and the effect on the joint after healing is also small; if the meniscus is heavily damaged, a subtotal resection or total resection is needed, and the postoperative effect is small in the early stage, but in the late stage, due to the lack of protection of the meniscus in the affected knee, the cartilage will be damaged compared to the healthy knee. However, in the late stage, because of the lack of protection of the meniscus on the affected knee, the cartilage will degenerate earlier than on the healthy knee, making it easier to develop traumatic arthritis and more prone to joint degeneration (i.e., easy to grow bone spurs). However, if the meniscus is not treated in a timely manner, not only will it be painful, but the roughness of the damaged area will cause secondary damage to the articular cartilage, making it more prone to traumatic arthritis and joint degeneration than meniscectomy. After the treatment of the damaged meniscus, there is no such stimulation, which not only protects the articular cartilage, but also significantly reduces the complications.
12.Introduction of surgical treatment for meniscus injury
① Simple partial or complete resection of the medial and lateral meniscus.
② Meniscus suture repair.
③Cruciate ligament reconstruction and meniscus repair. Meniscus suture surgery includes inside-out suture, outside-in suture, and total inside-out suture.