Torn meniscus and meniscus damage

An acute torn meniscus caused by injury is painful, especially when the knee is rotated or bent. Your knee might also swell. Some people hear a popping sound when the meniscus tears. The symptoms depend on the shape and size of the meniscus tear.

Smaller meniscus tears may not be immediately noticeable. They often start hurting only after a few hours or days have passed. Some people notice the knee injury only after several weeks, when they can no longer smoothly bend and extend the knee.

Larger meniscus tears are often more painful and cause the knee to swell. Plus, they can interfere with or restrict knee movement – the knee fells “locked.” If part of the meniscus tears off, it can block knee movement. It’s then impossible to fully straighten your leg.

Age-related changes or tears of the meniscus rarely cause symptoms. About 20% of people over age 40 have a torn meniscus or meniscus damage that can be seen in imaging, but doesn’t cause symptoms. In people with osteoarthritis of the knee, a worn meniscus is even more common: About 60% of people with osteoarthritis of the knee have changes or tears in the meniscus.

Age-related (degenerative) meniscus injury rarely causes knee pain. That’s why meniscus surgery is usually not considered an option for treating degenerative meniscus injury.

A meniscus is a C-shaped piece of cartilage between the shinbone and the thighbone. The medial meniscus is on the inside of the knee and the lateral meniscus on the outside of the knee. Both stabilize the movement of the knee joint, distribute pressure, and absorb shock. They also lubricate the joint cartilage and supply it with nutrients.

Each meniscus are attached to the joint surface of the tibia (shinbone) and the joint capsule, and the medial meniscus is also attached to the medial collateral ligament. That makes it less mobile and a little more prone to tears than the lateral meniscus.

Acute torn meniscus can result if the knee is twisted while it is bent – especially when your foot is flat on the ground. The forces acting on the meniscus can then be high enough for parts of the meniscus to tear.

Meniscus tears can be in different locations and have different sizes and shapes. The figure below shows typical examples of different types of meniscus tears.

Acute torn meniscus is common in sports where you quickly slow down from a fast run and change directions at the same time, for example in soccer, handball, tennis, and basketball. People who, due to an injury, no longer have an anterior cruciate ligament have a less stable knee and, as a result, a higher risk of meniscus injury.

The risk of wear-related meniscus damage is higher in jobs where you often squat or kneel. People who are very overweight or have to climb a lot of stairs are at higher risk too. Wear-related meniscus injury is more common in men than in women.

The exact prevalence of acute torn meniscus in Germany is unknown. It is estimated that about 1 out of 1,000 people have a meniscus injury every year. On the other hand, age-related changes in the meniscus are very common. These are normal and don’t need to be treated.

How long it takes for the symptoms of acute torn meniscus to improve and for you to be able to move your knee normally again depends on the size and type of tear and whether ligaments in the knee were injured too. Other important factors are the treatment method and your general physical condition.

After the damaged parts of the meniscus are removed, it takes about six weeks until you can hike or jog longer distances again. Many people need a few months until they feel comfortable and safe doing all activities. If the meniscus is sutured, longer rehabilitation is necessary. Then it takes about 4 to 6 months until most activities are possible again.

Even after surgery some of the symptoms may not go away, such as mild pain when climbing stairs, squatting, or kneeling.

Acute meniscus injury can reduce the knee’s range of motion and cause swelling if left untreated. In the long term, torn meniscus leads to a higher risk of osteoarthritis of the knee. The risk of osteoarthritis of the knee is also higher if damaged parts of the meniscus have been surgically removed.

To diagnose a torn meniscus, your doctor will ask how the injury happened and what symptoms you have. Then the doctor will check your knee with their hands (known as palpation) to find out where it’s painful or where parts of the meniscus might be bulging.

Your knee will then be bent and rotated, and the doctor will apply pressure to the different parts of the meniscus that might hurt if you've been injured. When straightening the bent leg, a snapping sensation can sometimes be felt as a sign of loose parts of the meniscus.

The meniscus can be seen in magnetic resonance imaging (MRI). Having an MRI may be considered if

• other knee injuries are suspected or
• meniscus surgery is planned.

Ultrasound imaging shows only the outermost parts of the meniscus. X-rays are not of much use in meniscus injuries. But they may be considered if bone injury is suspected too.

If the meniscus has been torn, the knee is first immobilized until acute pain and swelling improve. Elevating your leg and cooling your knee on the first few days after the injury help against swelling. Until the symptoms improve, it’s recommended to avoid strains on the knee like squatting, kneeling, or rotating and far bending movements.

A torn meniscus that doesn’t lead to pinching or blocking of the knee can sometimes be successfully treated conservatively, meaning without surgery. The same is true for some fresh meniscus injuries that lead to painful, but temporary inflammation. Conservative treatment options are:

• Anti-inflammatory painkillers, like diclofenac or ibuprofen
• Knee braces
• Weight loss (in case of massive overweight)
• Exercises for strengthening the muscles and improving stability, range of motion, and coordination

A torn meniscus is usually surgically treated if

• the knee no longer fully straightens (for example in case of bucket handle tear),
• symptoms are strong and frequent,
• the meniscus injury might have consequences like osteoarthritis of the knee, or
• other parts of the knee, like the cruciate ligaments, are injured too.

During surgery, the damaged parts of the meniscus are removed using arthroscopy. Ragged parts of the meniscus are shaved off to make the surface of the meniscus smoother. As much as possible of the meniscus is preserved. Removal of the damaged parts of the meniscus is called partial resection or smoothing of the meniscus.

Some meniscus tears can be sutured. This is known as meniscus repair, suture, or refixation. This method is thought to reduce later knee or osteoarthritis symptoms. But meniscus suture often has to be redone because the sutures fail. For this method, rehabilitation takes much longer too. Meniscus repair is a much-debated method since there are few strong studies on its benefits and drawbacks.

Well-trained muscles are the most important factor for your knee to function well. This makes rehabilitation after surgery important. During rehabilitation, you are taught muscle exercises and how to keep doing them in everyday life. Ideally, your doctor will put together an individual treatment plan for you in close consultation with the physiotherapists.

After partial resection of the meniscus, it takes about one week to walk normally and about six weeks to do sports again.

If the meniscus was sutured, it usually takes six weeks for you to be able to put weight on the operated leg again since before that time, the suture can easily fail. With meniscus repair, you can usually jog after four months and play ball sports after about six months.

When people are ill or need medical advice, they usually go to see their family doctor first. In our topic "Health care in Germany" you can read about how to find the right doctor – and our list of questions can help you to prepare for your appointment.