A meniscus tear is one of the most common injuries to the knee joint and affects both active athletes and older patients. The meniscus plays a key role in the knee’s stability, load distribution, and mobility. Depending on the type of injury, its location, and the extent of the tear, symptoms can vary widely.
Treatment for a meniscus tear ranges from conservative therapy to surgical intervention followed by rehabilitation.
The knee joint is the largest and most heavily stressed joint in the human body. It connects the thighbone to the shinbone, thereby transferring the entire weight of the torso to the lower leg.
The menisci are two crescent-shaped discs made of fibrocartilage. They are located in the knee joint between the thighbone and the shinbone. There is an outer meniscus and an inner meniscus.
Cross-section of the knee joint—menisci viewed 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 the synchronized rolling and gliding of the femoral condyles over the tibial tuberosity.
Other functions of the menisci:
Because of these important functions, it makes sense from a medical perspective to preserve the meniscus for as long as possible.
Watch the video below 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 well supplied with blood only in their peripheral zone, known as the “red zone.” These small blood vessels do not extend all the way to the center of the meniscus.
Therefore, this non-vascularized “white zone” of the meniscus is supplied with nutrients solely by synovial fluid. If the meniscus lacks sufficient nutrients and fluid, it becomes dry and brittle and degenerates. This makes injuries more likely, and tears cannot heal on their own.
We generally distinguish between
causes of meniscus tears.
A fresh traumatic meniscus tear most commonly occurs as a result of sports injuries. Especially during athletic activities involving rotational and shearing movements, very large forces often act on the knee joint. These forces lead to overloading and painful injuries to the structures of the knee joint, particularly the
Combined injuries involving the cruciate ligaments and meniscus (cruciate ligament tear, medial collateral ligament tear, and meniscus tear) are also common.
© bilderzwerg / Fotolia
The vast majority of meniscus tears are caused by degenerative meniscus damage. The menisci are often chronically overloaded over many years, for example due to improper loading
Even many small instances of overexertion during sports or work can wear down the meniscus tissue. Eventually, a single instance of overexertion can cause the already damaged tissue to tear.
are the result.
If left untreated, the torn pieces of meniscus repeatedly become trapped between the joint surfaces of the thigh and lower leg. The cartilage on the joint surfaces suffers lasting damage as a result of this entrapment. If this mechanism is not stopped through surgery, osteoarthritis (joint wear) will develop over time in the affected joint segment.
In sports injuries that damage the meniscus, the immediate incident itself is already an indication of meniscus damage. Typical signs of a meniscus tear include:
An experienced physician can make a relatively confident preliminary diagnosis of a meniscus tear based on a physical examination. An X-ray can rule out bone damage.
If the findings are unclear, magnetic resonance imaging (MRI) can then definitively confirm meniscus damage.
A meniscus tear leads to knee instability and, as a result, to excessive joint wear (osteoarthritis). Therefore, surgical stabilization as early as possible is essential.
As a rule, fresh meniscus tears near the base can be very effectively treated by the surgeon using arthroscopic sutures or suture systems. The affected area heals and reforms into intact meniscus tissue composed of fibrocartilage.
A meniscus tear is treated arthroscopically. The video shows the procedure for this minimally invasive surgery:
Arthroscopic treatment of meniscus injuries is now an established and routine procedure. It is performed in many orthopedic clinics and surgical centers.
The options for surgical treatment depend on the type of meniscus tear. The location and how recent the tear is are also important factors.
The guiding principle in meniscus surgery is: Remove as little tissue as possible, but as much as necessary. All potentially damaging portions of the meniscus are removed using specialized instruments. In most cases, no more than 1/3 or 2/5 of the meniscus tissue needs to be removed.
Most meniscus tears are degenerative in nature (wear and tear). In such cases, repair (suturing) is no longer possible, and the torn tissue must be removed.
The removal of the damaged meniscus tissue (resection) can be performed very gently using arthroscopy. It is a short procedure that is usually performed under light general anesthesia 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 through additional tiny incisions. In this way, the surgeon can repair the injured structures.
In general, such surgeries today place very little strain on the patient.
If the patient’s health and home situation permit, the surgery can be performed on an outpatient basis. The patient can then leave the recovery room approximately 2 hours after surgery, accompanied by someone and using forearm crutches
Knee arthroscopy does not require long skin incisions © smartmediadesign | AdobeStock
After the surgery, a soft padding 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 bandage is removed the day after surgery and replaced with waterproof adhesive bandages, which protect the wound until the sutures are removed after one week.
Your knee should be iced and elevated to minimize swelling as much as possible. During the first few days after surgery, the small incision sites—about 5 mm wide—may be somewhat tender. The sensation of fluid “splashing” in your knee joint is no cause for concern. This is residual fluid from the arthroscopy and will disappear on its own.
You may shower carefully using the waterproof bandages. You should avoid taking baths and swimming for 10 days to prevent water from entering the joint from the outside. You will need crutches for a while after the surgery. However, it is usually possible to partially bear weight on the operated leg—up to about 30 kg—on the first day after surgery.
Walking aids are necessary in the period following surgery © S Amelie Walter | AdobeStock
You should begin isometric exercises immediately. These should be performed every hour and help maintain the thigh muscles. You should avoid saunas and tanning beds for 3 weeks after surgery (risk of swelling).
Running is possible starting in the 4th week, and stop-and-go sports starting in the 6th week after surgery. Overall, the rule is: Listen to your knee! Increase the intensity of all activities gradually and pay attention to how the joint responds.
Make sure you do not subject your knee to impact loads (such as wearing high heels) during the first few weeks after surgery. In older people in particular, excessive strain following meniscus surgery can lead to so-called fatigue fractures.
In the case of fresh meniscus tears in the well-vascularized periphery, it is possible to suture the torn meniscus back together. This applies in particular to so-called basket-handle tears.
Certain areas of the meniscus are difficult to reach, and care must be taken not to damage the nerves and blood vessels in the popliteal fossa. Therefore, special suturing instruments are required for refixation in the posterior horn region of the meniscus.
Meniscus repair is also performed today using a minimally invasive technique under arthroscopic guidance.
Postoperative care following meniscus suturing is considerably more extensive than after meniscus resection:
Partial weight-bearing (10–20 kg) for 3 weeks using two forearm crutches and wearing a stabilizing brace with temporary restriction of movement.
For 3 months, deep squats and sports that place stress on the knee are not permitted.
However, the following are permitted:
Many injuries can no longer be sutured. In these cases, the meniscus tear is located in the avascular portion of the meniscus, or the tissue is already irreparably damaged.
Studies have shown that even a partial removal of meniscus tissue can lead to increased stress on the joint. This can result in degenerative changes to the articular cartilage. Consequently, there is a high probability that knee osteoarthritis will develop later on. This condition is associated with significant pain and limited mobility.
An international team led by the renowned American sports medicine specialist Dr. Steadman has developed a biological implant for such cases. It stimulates the body to form meniscus-like tissue, thereby filling 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 (manufacturers: ReGen Biologics—Menaflex; and Ormed-DJO—Actifit). Its shape is modeled after the human medial or lateral meniscus, respectively.
The implant is sutured into place arthroscopically to replace the removed meniscus tissue. It then harnesses the body’s ability to regenerate its own tissue. The implant’s porous structure serves as a guide for the ingrowth of new tissue.
The body’s own cells gradually migrate into the implant and form meniscus-like tissue. After about one year, the CMI has largely been resorbed and replaced by the body’s own tissue.
Results from clinical studies in the U.S. and Europe demonstrate that the meniscus implant supports the growth of new tissue. Pre-existing pain is significantly reduced, and patients are able to return to a level of activity similar to that before their injury.
© westfotos.de / Fotolia
The CMI meniscus implant was first implanted in patients in the U.S. in 1993 as part of a feasibility study. The positive results led to the initiation of multicenter studies in the U.S. and Europe in 1997. In 2000, based on these positive results, the CE mark of conformity was issued for the medial implant. The CMI for the lateral meniscus is now also approved in Europe and in clinical use.
The American multicenter study involving over 300 patients also demonstrates the benefits of the CMI in terms of
meniscal tissue regeneration,
The average duration of a CMI implantation procedure is comparable to that of a complex meniscus repair
To date, more than 1,400 patients worldwide have undergone successful CMI surgery. These were primarily people who placed great importance on regaining their ability to participate in sports. In approximately 90 percent of treated CMI patients, the intended treatment success can be demonstrated by clear tissue regeneration.
After treatment, these patients, on average, regain 70 percent of their original meniscus tissue. This was the finding of a randomized multicenter study (U.S.) involving over 300 patients.
The implant becomes increasingly durable as the body’s own cells integrate into it. For the treatment to be successful, the patient must consistently follow the specific rehabilitation program at all times.
With a meniscus implant, patients can resume athletic activities similar to those they engaged in before the injury © Dudarev Mikhail | AdobeStock
From a medical standpoint, the following conditions should also be met:
Postoperative care extends over a total period of approximately 6 months. Initially, the load and range of motion must be increased slowly and gradually. After two months, the operated knee can generally bear a full load again. The patient must now begin rehabilitation training to resume their usual athletic activities.
However, in consultation with the treating physician, sedentary work—such as office work—is possible as early as the first few weeks after surgery.
The tissue that is regenerating undergoes a maturation process. Therefore, even if the patient is pain-free, they must not put full weight on their knee at first. After approximately 6 months, athletic activities can then be resumed at the usual level.
A meniscus tear in the knee often manifests as knee pain, pain in the knee joint, stabbing pain, as well as pain and swelling—symptoms that indicate a meniscus tear and significantly impair the affected knee in daily life.
Depending on the type of tear—specifically whether the medial or lateral meniscus is affected or whether it is an acute meniscus tear—a meniscus tear can cause the knee to lock and place additional strain on the knee ligaments, especially when the knee is bent or if the knee was already damaged.
If a meniscus tear is diagnosed, treatment depends on whether conservative measures are sufficient or whether surgical treatment or procedures are necessary—for example, in cases of injured knees with severe pain.
In some cases, a partial meniscus resection is performed to relieve pain, initially stabilize the knee, and reduce stress on the joint.
Rehabilitation after a meniscus tear is crucial, as the knee must be moved regularly in the weeks following surgery to reduce pain and restrictions of movement and to restore joint function.
Overall, the topic of meniscus tears shows that such tears often result from stress on the knee, and that targeted treatment and rehabilitation help to further protect the knee and prevent long-term symptoms.
What is a meniscus tear?
A meniscus tear is an injury to the meniscus in the knee joint in which the fibrocartilaginous tissue is partially or completely torn. This injury can result from acute trauma or degenerative changes.
What are the symptoms of a meniscus tear?
Typical symptoms of a meniscus tear include knee pain, swelling, locking of the knee joint, and limited range of motion. The symptoms often worsen with physical activity or when bending the knee.
How is a meniscus tear diagnosed?
The diagnosis is made through a clinical examination, specialized functional tests, and imaging techniques such as MRI. These methods allow for a reliable assessment of meniscus damage and associated injuries.
When is surgery necessary for a meniscus tear?
Surgery is necessary if conservative treatment is insufficient, severe pain persists, or the knee locks. The procedure is often performed arthroscopically.
How long does rehabilitation take after a meniscus tear?
Rehabilitation depends on the type of treatment and can take several weeks. Physical therapy plays a central role in restoring the knee’s range of motion, muscle strength, and load-bearing capacity.
