The knee joint is one of the most complex joints in the human body, containing two menisci that act as shock absorbers between the thigh and lower leg. Meniscus tears are among the most common injuries in orthopedics and trauma surgery. Whether caused by an acute twist during sports or by gradual wear and tear with age, when these crescent-shaped cartilage discs tear or become compressed, it often leads to knee pain and limited mobility. Immediate surgery is not always necessary. Often, an experienced specialist or orthopedic surgeon can treat meniscus damage conservatively, for example through immobilization and physical therapy. The choice of the right treatment depends largely on whether the injury is a traumatic tear or degenerative meniscus damage.
What is a meniscus?
The menisci are C-shaped fibrous cartilage pads. They are wedged between the articular surfaces of the femur and tibia in the knee joint. Here, they ensure
- an increase in the contact area,
- shock absorption, and
- distribute body weight.
They are also important for joint stability and protect the knee from excessive strain. The human knee has two menisci: the lateral meniscus and the medial meniscus.
The menisci only become noticeable through pain when there is excessive strain or injury.
Causes of meniscus damage
The meniscus is well supplied with blood only in its peripheral zone (the red zone). This makes the cartilage pads more susceptible to injury, as they can dry out and become brittle. Tissue damage also heals more slowly.
Meniscus injuries are among the most common sports injuries. These injuries primarily occur in sports that place heavy strain on the knee. These include, above all:
- Soccer
- Tennis
- Basketball
- Skiing
- Snowboarding
- Water skiing
- Handball
- Squash
- Javelin or discus throw
- Skateboarding
- Cycling
- Fencing
A meniscus injury is usually caused by a sudden twist of the knee joint or by intense flexion and extension movements. These movements cause the free edge of the meniscus to become trapped between the joint surfaces, resulting in a partial or complete tear of the meniscus.
In contrast, there is degenerative meniscus damage caused by wear and tear. This develops gradually starting in middle age due to pre-existing damage and unfavorable stress on the joint.
Alignment abnormalities and obesity are major risk factors. However, certain occupational groups, such as tile setters, also frequently suffer from meniscus damage. Their work involves kneeling, which places excessive strain on the menisci.
Different Types of Damage
Orthopedics distinguishes between different forms of meniscus damage. Among the most common is a meniscus rupture (meniscus tear). The medial meniscus is affected more frequently than the lateral meniscus. Depending on the direction of the tear, a distinction is made between
- oblique tears,
- longitudinal tears, or
- radial tears
.
A meniscus contusion is a less severe form of meniscus injury. It is usually caused by sports injuries and heals after a rest period of about three weeks.
One of the congenital conditions is the disc-shaped meniscus. During embryonic development, the menisci are initially formed as discs. Over the course of childhood, they thin out from the center toward the edges, resulting in the typical crescent shape.
In the case of the lateral meniscus, this degradation may stop prematurely, causing the meniscus to remain disc-shaped. This shape is disadvantageous when subjected to mechanical stress. As a result, the meniscus cannot give way during certain movements. This carries the risk of a painful snapping sensation, which typically manifests between the ages of 6 and 8.
In severe cases, tears can develop that extend all the way to the joint capsule, leading to the loss of large portions of the lateral meniscus. Therefore, in children with snapping and locking symptoms, a disc-shaped meniscus should be considered early on.
Over time, the meniscus also wears down. Its fibers lose elasticity and stability. As the meniscus tissue continues to flatten, it gradually loses volume and eventually tears.
Doctors refer to this as degenerative meniscopathy, which is associated with the development of osteoarthritis in later stages. In addition to leg alignment abnormalities (such as bowlegs and knock-knees), excessive strain is also a common cause of degenerative meniscus damage.
Symptoms of Meniscus Injury
A typical symptom of an acute meniscus tear is sudden, sharp pain. Swelling also develops in the affected knee.
If the medial meniscus is affected, the pain often occurs in the inner joint space. In contrast, with injuries to the lateral meniscus, patients experience tenderness along the outer joint space.
In the case of a partial meniscus tear, there is a risk that a piece of the meniscus will become trapped. This, in turn, results in a painful knee lock. Occasionally, cracking or snapping sounds may also be heard.
In cases of degenerative meniscus damage, the symptoms are usually less pronounced. Knee pain typically occurs, especially during physical activity. A feeling of instability is also common.
Diagnosis of Meniscus Injury
The best person to consult for an examination if meniscus damage is suspected is an orthopedic surgeon. The surgeon will first ask the patient about their symptoms and then perform a physical examination of the knee.
This examination includes specific flexion and rotation tests to assess the functional integrity of the menisci. In most cases, the physical examination alone provides sufficient information. It is also important to rule out other injuries, such as a meniscal contusion or damage to the articular cartilage.
As a secondary symptom, the irritation leads to inflammation of the joint accompanied by effusion. If there is significant joint effusion in the knee, a puncture can provide relief and reduce pain. During this procedure, the doctor uses a hollow needle to withdraw fluid, which is then analyzed for components such as
- cells,
- inflammatory substances,
- particles, or
- bacteria
.
An X-ray is only useful if there is suspicion of bone injuries or structural abnormalities. The best diagnostic results can be achieved with magnetic resonance imaging (MRI). An MRI allows for a precise assessment of cartilage, bone, and soft tissues.
If further clarification is needed, an arthroscopy (knee endoscopy) can be performed. A meniscus tear can already be surgically repaired using this procedure.
Treatment of Meniscus Damage
The method of treating meniscus damage depends on the extent of the injury. Physical fitness also plays an important role
- the patient’s physical fitness,
- the patient’s age, and
- the severity of the pain.
Surgery is not always necessary for every meniscus injury. Minor lesions that do not cause impingement are usually treated with rest and physical therapy.
However, surgery is necessary if the meniscus injury is extensive and causes instability or mechanical problems. Without surgical intervention, there is a risk of cartilage damage and osteoarthritis.
The surgery is usually performed arthroscopically. The patient is given either regional or general anesthesia. Depending on the injury, the procedure can be performed on an inpatient or outpatient basis. Open knee surgeries are rarely performed anymore.
The video shows the procedure for arthroscopic meniscus repair:
In meniscus surgery, the goal is to remove the portions that
- no longer serve a function or
- cause mechanical interference that could lead to further cartilage damage.
This allows tears to be carefully excised and the edges of the tear to be gently smoothed. This part of the surgery must be performed as gently as possible, since every functional part of the meniscus is still needed.
Postoperative Care
Following the surgery, knee movement and athletic activities are gradually resumed. Depending on the surgical technique, it may take several weeks to three months before the knee can once again bear a full load.
Conclusion
Do not take meniscus damage lightly. It is advisable to consult a doctor
- to prevent further joint damage and osteoarthritis, and
- before resuming athletic activities.
Unfortunately, the controversial discussions about the merits of meniscus surgery are often influenced by cost pressures and one-sided interpretations of studies. In principle, all treatment options should always be considered. Therefore, for degenerative meniscus injuries, conservative therapy is always recommended as the first step.
The more pronounced the mechanical symptoms are, the higher the success rate of surgery. However, acute traumatic meniscus tears can only heal on their own if they are surgically sutured immediately after the injury.
FAQ: The 8 Most Important Questions About Meniscus Injuries
How can you tell if you have a meniscus injury?
Meniscus damage is suspected when sharp pain occurs in the knee during activities such as climbing stairs or squatting. The symptoms depend on the extent of the tear. Pain and swelling in the knee area are common. Another typical sign is joint locking, in which the knee cannot be fully bent or straightened because a piece of the meniscus has become lodged in the joint space. Pain in the back of the knee can also indicate meniscus damage.
What causes a meniscus tear?
Meniscus tears are among the most common knee injuries and have various causes. In young people, a meniscus tear often occurs acutely during sports, for example, due to a rapid inward rotation of the knee while the foot is planted firmly on the ground, as happens in soccer or skiing. In older adults, degenerative processes tend to play a greater role. Years of stress cause the tissue to become brittle, so that even minor impacts—such as standing up from a squatting position—can lead to a tear. Such damage to the meniscus often develops gradually.
How is meniscus damage treated?
Treatment for meniscus injuries depends on the patient’s age, activity level, and the type of tear. Non-surgical treatment—that is, conservative therapy—is often possible for small, stable tears or degenerative changes. This involves physical therapy to strengthen the muscles, anti-inflammatory medications, and temporary rest. However, if the meniscus has an unstable tear or is mechanically blocked, surgery using arthroscopy is usually required.
Why is the medial meniscus more commonly affected?
There are two menisci in the knee joint, which are crescent-shaped discs of cartilage. The medial meniscus is firmly fused to the joint capsule and the medial collateral ligament, which makes it less mobile. As a result, it cannot move out of the way during sudden twisting motions and is therefore more frequently injured than the lateral meniscus, which is more mobile. Meniscus injuries, particularly those involving the medial meniscus, are therefore a common occurrence in orthopedics.
How is the diagnosis made?
If you visit a doctor with knee pain, the first step is a physical examination, during which the orthopedic surgeon checks the knee for tenderness, swelling, and range of motion. Special meniscus tests induce pain during rotation and flexion. To confirm the diagnosis and assess the exact extent of the tears as well as the condition of the cartilage and ligaments, imaging diagnostics using MRI (magnetic resonance imaging) is the gold standard.
What happens during meniscus surgery?
Surgery is usually performed using a minimally invasive technique called arthroscopy. The goal is to preserve as much meniscus tissue as possible. For fresh tears in the well-vascularized zone, the meniscus is sutured (meniscus repair). However, if the tissue is severely damaged or torn off, the defective portion of the meniscus is removed sparingly (partial resection). This alleviates acute symptoms but increases the long-term risk of osteoarthritis on the joint surface.
Can a meniscus tear heal on its own?
The meniscus tissue is well supplied with blood only in the outer third. Tears in this “red zone” have some potential for healing and may scar over with conservative treatment. However, tears in the inner, non-vascularized zone do not heal on their own. While conservative therapy can help alleviate inflammation and pain in these cases, the mechanical damage remains and can damage the cartilage if stress on the joint continues.
What are the consequences of untreated meniscus damage?
If an unstable meniscus tear is left untreated, the loose edge of the meniscus can become trapped between the joint surfaces and rub against the cartilage like sandpaper. This leads to permanent damage to the joint surface and accelerates the development of osteoarthritis (joint wear). Therefore, persistent pain or locking should always be evaluated by a doctor to prevent further damage to the knee joint.
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