The knee joint has two important buffer discs: the medial and lateral meniscus. A meniscus tear can occur due to traumatic (accident-related) or degenerative (wear-related or overuse-related) causes. Surgical intervention is always necessary for healing. Here you will find further information and selected meniscus tear specialists and centers.
The knee joint is the largest and most heavily used joint in our body. It connects the thigh and lower leg. As a result, it transfers the entire load of the trunk to the lower leg.
The menisci are two crescent-shaped discs of fibrocartilage. They are located in the knee joint between the upper and lower leg bones. There is an outer and an inner meniscus.
Cross-section of the knee joint - menisci seen from above © bilderzwerg / Fotolia
The menisci play an extremely important role in the function of the knee joint. Particularly crucial is
Together with the cruciate ligaments, the menisci ensure that the femoral rollers roll and glide synchronously on the tibial plateau.
Other tasks of the menisci:
Because of these important functions, it makes sense from a medical point of view to preserve the meniscus for as long as possible.
Watch the following video to see how the knee joint is structured and where the menisci are located:
The menisci are not completely permeated by blood vessels. They are only well supplied with blood in their peripheral zone, the so-called red zone. These small blood vessels do not reach the center of the meniscus.
Therefore, this white zone of the meniscus, which is not supplied with blood, is only supplied with nutrients by the synovial fluid. If the meniscus has too few nutrients and too little fluid, it becomes dry and brittle and degenerates. This makes damage more likely and the tears cannot heal on their own.
We basically differentiate between
causes of meniscus tears.
The fresh traumatic meniscus tear occurs primarily as a result of sports injuries. Very high forces often act on the knee joint, particularly during sporting activities with twisting and shearing movements. This leads to overloading and painful injuries to the knee joint structures, especially the cruciate ligaments.
Combined injuries to the cruciate ligament and meniscus(cruciate ligament tear, medial collateral ligament tear and meniscus tear) also occur frequently.
© bilderzwerg / Fotolia
Degenerative meniscus damage accounts for the majority of meniscus tears. The menisci are often chronically overloaded over many years, for example due to unfavorable loads
Many small overloads during sport or at work also wear down the meniscus tissue. Ultimately, a single overload can lead to a tear in the damaged tissue.
are the result.
If left untreated, the torn parts of the meniscus repeatedly get caught between the joint surfaces of the thigh and lower leg. The cartilage of the joint surfaces is permanently damaged by this trapping. If this mechanism is not stopped by an operation, arthrosis (joint wear and tear) of the affected joint section will develop over time.
In the case of sports injuries that damage a meniscus, the immediate event of the accident already provides an indication of the damage to the meniscus. Typical signs of a meniscus tear are
An experienced doctor can make a relatively reliable diagnosis of a meniscus tear through examination. X-rays can be used to rule out damage to the bone.
If the findings are unclear, magnetic resonance imaging(MRI) can then provide reliable evidence of meniscus damage.
A meniscus tear leads to instability of the knee and subsequently to excessive joint wear(osteoarthritis). Surgical stabilization as early as possible is therefore essential.
As a rule, fresh meniscus tears close to the base can be treated very well by the surgeon using arthroscopic sutures or suture systems. The affected area grows back and forms intact meniscus tissue from fibrocartilage.
A meniscus tear is operated on arthroscopically. The video shows the procedure for this minimally invasive operation:
The arthroscopic treatment of meniscus damage is now an established and routine procedure. It is performed in many orthopaedic clinics and surgical centers.
The options for surgical treatment depend on the type of meniscus tear. The location and freshness of the tear are also important.
The motto for meniscus surgery is: remove as little tissue as possible, but as much as necessary. All potentially damaging parts of the meniscus are removed using special instruments. In most cases, no more than 1/3 or 2/5 of the meniscus substance needs to be removed.
Most meniscus tears are degenerative in nature (wear and tear damage). A repair (suture) is then no longer possible and the torn tissue must be removed.
Removal of the damaged meniscus tissue (resection) can be carried out very gently using arthroscopy. It is a short procedure that is usually performed under a light general anesthetic or spinal anesthesia.
A miniature camera is inserted into the knee joint through a small incision in the skin. This allows the affected knee to be examined. Surgical instruments and any necessary implants are gently inserted into the joint via further tiny incisions. In this way, the surgeon can repair the injured structures.
Nowadays, such operations generally represent very little stress for the patient.
If the patient's health and home conditions allow, the operation can be performed on an outpatient basis . The operated patient can then leave the recovery room about 2 hours after the operation, accompanied and with the help of forearm crutches
No long incisions are necessary for knee arthroscopy © smartmediadesign | AdobeStock
After the operation, a soft padded bandage and an elastic compression bandage are applied. The bandage is comfortable and can absorb fluid from the arthroscopy and residual blood from the puncture sites. A small tube may be inserted into the joint to drain wound fluid.
The dressing is removed the day after the operation and replaced with waterproof plasters, which protect the wound until the stitches are removed a week later.
Your knee joint should be cooled with ice and elevated to keep swelling to a minimum. During the first few days after the operation, the small, approx. 5 mm wide puncture sites may be somewhat sensitive. The feeling of fluid "rippling" in your knee joint is no cause for concern. This is residual fluid from the arthroscopy and will disappear by itself.
You can shower carefully with the waterproof plasters. Bathing and swimming should be avoided for 10 days to prevent water from entering the joint from outside. You will need crutches for some time after the operation. However, it is usually possible to put some weight on the operated leg on the first day after the operation, weighing around 30 kg.
Walking aids are necessary in the period after the operation © S Amelie Walter | AdobeStock
Isometric tensing exercises should be started immediately. They are performed every hour and help to maintain the thigh muscles. You should avoid the sauna/sunbed for 3 weeks after the operation (risk of swelling).
Running is possible from the 4th week and Stop&Go sports from the 6th week after the operation. The general rule is: listen to your knee! Increase all loads slowly and feel how the joint reacts.
Make sure that you do not put any impact loads (hard heels) on the knee in the first few weeks after the operation. Older people in particular can suffer so-called fatigue fractures after meniscus surgery if they put too much strain on the joint.
In the case of fresh meniscus tears in the rim with blood supply, it is possible to suture the torn meniscus again. This applies in particular to so-called basket handle tears.
Certain areas of the meniscus are difficult to reach and the nerves and vessels in the hollow of the knee must not be damaged. Special suture instruments are therefore required for refixation in the posterior horn area of the menisci.
Today, meniscus refixation is also performed using minimally invasive techniques under arthroscopic control.
The follow-up treatment after a meniscus suture is considerably more complex compared to meniscus resection:
Partial weight bearing (10-20kg) for 3 weeks with two forearm crutches and wearing a stabilizing splint with temporary restriction of movement.
No weight-bearing in deep knee flexion and no knee-straining sports are permitted for 3 months.
However, the following are permitted
Many injuries can no longer be sutured. In these cases, the meniscus tear is located in the part of the meniscus that is not supplied with blood or the tissue is already irreparably damaged.
Studies have shown that even partial removal of the meniscus tissue can lead to increased stress. This can lead to degenerative changes in the joint cartilage. As a result, knee osteoarthritis is very likely to develop later on. This is associated with considerable pain and restricted movement.
An international team led by the well-known American sports physician Dr. Steadman has developed a biological implant for such cases. It stimulates the body to form meniscus-like tissue and thus fills the defect.
How does the meniscus implant work?
The meniscus implant is a biological and resorbable implant. It consists of highly purified collagen with a sponge-like structure or a polyurethane scaffold (suppliers ReGen Biologics: Menaflex and Ormed-DJO: Actifit). The shape is based on the human inner or outer meniscus.
The implant is sutured arthroscopically in place of the removed meniscus tissue. It then utilizes the body's ability to regenerate its own tissue. The porous structure of the implant serves as a guide rail for the ingrowth of new tissue.
The body's own cells gradually migrate into the implant and form meniscus-like tissue. After approximately one year, the CMI is largely degraded and replaced by the patient's own tissue.
The results from the clinical studies in the USA and Europe show that the meniscus implant supports the growth of new tissue. Previous pain is significantly reduced and patients return to a similar level of activity as before the injury.
© westfotos.de / Fotolia
The CMI meniscus implant was first operated on patients in a feasibility study in the USA in 1993. The positive results led to multi-center studies being started in the USA and Europe in 1997. In 2000, the CE mark of conformity for the medial implant was issued due to the positive results. In the meantime, the CMI for the lateral meniscus has also been approved in Europe and is in clinical use.
The American multicenter study with over 300 patients also confirms the benefits of the CMI in terms of
the formation of new meniscal tissue,
The average duration of a CMI implantation operation is comparable to that of a complex meniscus refixation operation
To date, more than 1400 patients worldwide have been successfully operated on with the CMI. These were mainly people who attached great importance to regaining their sporting activity . In around 90 percent of treated CMI patients, the intended success of the treatment can be demonstrated by clear tissue regeneration.
After treatment, these patients regained an average of 70 percent of their original meniscus substance. This was the result of a randomized multicenter study (USA) with over 300 patients.
The implant becomes increasingly resistant as the body's own cells grow into it. To ensure success, the patient must consistently adhere to the specific rehabilitation program at all times.
With a meniscus implant, patients can return to the same level of sporting activity as before the injury © Dudarev Mikhail | AdobeStock
The following conditions should also be met from a medical point of view:
The follow-up treatment extends over a period of approximately 6 months. Initially, weight-bearing and range of motion must be increased slowly and continuously. After two months, the operated knee can usually be fully loaded again. The patient must now begin training for their usual sporting activities.
However, in consultation with the attending physician, sedentary activities - such as working in an office - are possible in the first few weeks after the operation.
The tissue that is being built up undergoes a maturing process. For this reason, the patient must not initially put full weight on their knee, even if they are pain-free.
After around 6 months, sporting activities can be resumed to the usual extent.
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