What are meniscal tears?

A tear in the meniscus is a common injury. It can cause pain and swelling of the knee and make it hard to move.

What is a meniscus?

Each of your knees has two menisci - crescent-shaped pieces of cartilage that pad the bones in your knee joint. They act as stabilisers, lubricants and shock absorbers. [1] [2] The blood supply to the menisci is precarious; the outer edges of a meniscus receive a good blood supply, so therefore tears in this 'red zone' have a better chance of healing than those in the inner 'white zone'. This is important when considering treatment options.

The menisci are pads of cartilage located at the ends of knee bones.The meniscus. 
 

Cartilage

A tough, flexible connective tissue found in various parts of the body including the joints and larynx.

1. Bernstein, J. (2010). In brief: meniscal tears. Clinical Orthopaedics and Related Research 468: 1190–1192.

2. Maffulli, N., Longo, U.G., Campi, S., et al. (2010). Meniscal tears. Open Access Journal of Sports Medicine 1: 45–54.

Causes

Meniscal tears are most often caused by twisting injuries - a sudden change of direction while running or playing sport that causes the knee to 'twist' while it is bent, putting strain on the menisci. In many cases, a meniscal tear is just one of several problems that follow a knee injury, such as an anterior cruciate ligament injury.

Rarely, a meniscal tear can also occur without any injury, but as a result of gradual wear. This is more common in older people. [2]

The torn meniscus can cause pain. In addition, fragments of the meniscus can get in the way of the knee's movement. For example: a 'locked' knee happens when a piece of torn meniscus lodges between the bones, preventing the knee from straightening completely.

2. Maffulli, N., Longo, U.G., Campi, S., et al. (2010). Meniscal tears. Open Access Journal of Sports Medicine 1: 45–54.

Risk factors

People at greater risk of meniscal tears include: [2] [3]

  • Young adults who play sports, especially contact sports such as football (soccer) and rugby;
  • Adults over 60 years of age;
  • Men;
  • People who kneel or squat frequently (e.g., at work), and;
  • People who climb stairs frequently (more than 30 flights a day).

2. Maffulli, N., Longo, U.G., Campi, S., et al. (2010). Meniscal tears. Open Access Journal of Sports Medicine 1: 45–54.

3. Snoeker, B.A.M., Bakker, E.W.P., Kegel, C.A.T., et al. (2013). Risk factors for meniscal tears: a systematic review including meta-analysis. The Journal of Orthopaedic and Sports Physical Therapy 43: 352–367.

Signs and symptoms

Signs and symptoms of a meniscal tear include: [4]

  • A cracking or popping sound can sometimes be heard when the tear happens;
  • Knee pain - sometimes immediately after the injury, and sometimes developing in the hours after the injury;
  • Knee swelling;
  • Knee stiffness and loss of movement, and;
  • Knee 'popping', 'locking', 'catching' or otherwise not working properly, or feeling unusual.

Nearly two thirds of all meniscal tears show no symptoms. [5]

4. Murtagh, J., MD. Murtagh’s General Practice. McGraw Hill Education.

5. Englund, M., Guermazi, A., Gale, D., et al. (2008). Incidental meniscal findings on knee MRI in middle-aged and elderly persons. New England Journal of Medicine 359: 1108–1115.

Methods for diagnosis

Your doctor can suspect a meniscal tear based on your symptoms and a physical examination. They will then decide if an MRI scan should be done. MRI is the best way of diagnosing meniscal tears, especially if surgery is being considered.

Arthroscopy can also give an accurate diagnosis, but it is an invasive surgical procedure. [2]

Arthroscopy

A procedure that allows your doctor to see inside a joint, such as your knee or hip. An arthroscope is a tiny telescope with a light attached to its end. It is inserted via a small incision and guided through the joint needing examination.

MRI

A type of imaging that uses a magnetic field and low-energy radio waves, instead of X-rays, to obtain images of organs.

2. Maffulli, N., Longo, U.G., Campi, S., et al. (2010). Meniscal tears. Open Access Journal of Sports Medicine 1: 45–54.

Types of treatment

First aid

Immediate treatment of meniscal tears aims to ease the pain and prevent further damage. It can involve:

  • Rest;
  • 'Icing' the knee - applying an icepack to the knee, and;
  • Avoiding movement and activity that can strain the knee (such as sport, running, walking up stairs, cycling, dancing).

Further treatment

Further treatment of meniscal tears is divided into three categories - rehabilitation, repair and removal. Deciding between them depends on your age, health and activity level, and on the shape, orientation, depth and location of the tear. [2] [6]

Until 1948, the meniscus was thought to have no function, and was often removed completely when tears occurred. Then it was discovered that although removing the meniscus relieved the symptoms in the short-term, it led to more knee problems in the long-term.

Today, the aim is to conserve the meniscus as much as possible; therefore, rehabilitation and repair are preferred to removal. Surgery to remove the meniscus (meniscectomy), when performed, usually removes only part of the torn meniscus.

Rehabilitation

Rehabilitation is the first type of treatment considered for meniscal tears, since it does not require surgery and can, in many cases, be as effective as surgery. [7] [8]  Your doctor can advise you on rehabilitation measures, including:

  • Rest and recuperation (for minor tears, this can be enough);
  • Avoiding movement and activity that can strain the knee (such as sport, running, walking up stairs, dancing);
  • Physiotherapy - physical exercises that strengthen leg muscles to take the load off your knee joint;
  • Braces and crutches, to take the load off your knee joint, and;
  • Anti-inflammatory and pain-relief medications. [1]

Repair

Repair of the damaged meniscus is normally done by arthroscopy. There are several techniques, including sutures, implants, or both. [2] Repair is more successful in younger people with certain types of tears. Repair surgery must be followed by a rehabilitation period.

In some cases, open knee surgery is preferred to arthroscopy.

Removal

Arthroscopic partial meniscectomy is a very common orthopaedic procedure. [8]  During menisectomy, the surgeon removes any pieces of meniscus that are interfering with the knee's function. They then trim, reshape and repair the meniscus to prevent further tears.

Arthroscopy is one of the treatments for knee pain.Knee arthroscopy. 

Arthroscopy

A procedure that allows your doctor to see inside a joint, such as your knee or hip. An arthroscope is a tiny telescope with a light attached to its end. It is inserted via a small incision and guided through the joint needing examination.

Orthopaedic

The medical specialty that look at deformities and diseases of the bones.

Physiotherapy

A healthcare profession that treats bodily weaknesses or defects with physical remedies, such as massage or exercise.

Sutures

Stitches used to secure the edges of a wound together. They are inserted using a sterile, sharp needle and surgical thread of various types.

2. Maffulli, N., Longo, U.G., Campi, S., et al. (2010). Meniscal tears. Open Access Journal of Sports Medicine 1: 45–54.

6. Mordecai, S.C., Al-Hadithy, N., Ware, H.E., et al. (2014). Treatment of meniscal tears: An evidence based approach. World Journal of Orthopedics 5: 233–241.

7. Katz, J.N., Brophy, R.H., Chaisson, C.E., et al. (2013). Surgery versus physical therapy for a meniscal tear and osteoarthritis. New England Journal of Medicine 368: 1675–1684.

8. Sihvonen, R., Paavola, M., Malmivaara, A., et al. (2013). Arthroscopic partial meniscectomy versus sham surgery for a degenerative meniscal tear. New England Journal of Medicine 369: 2515–2524.

1. Bernstein, J. (2010). In brief: meniscal tears. Clinical Orthopaedics and Related Research 468: 1190–1192.

2. Maffulli, N., Longo, U.G., Campi, S., et al. (2010). Meniscal tears. Open Access Journal of Sports Medicine 1: 45–54.

8. Sihvonen, R., Paavola, M., Malmivaara, A., et al. (2013). Arthroscopic partial meniscectomy versus sham surgery for a degenerative meniscal tear. New England Journal of Medicine 369: 2515–2524.

Potential complications

Meniscal tears can contribute to the development of osteoarthritis later in life.

Meniscectomy can change the load distribution in the knee and cause changes in bone and cartilage function. [2]

Cartilage

A tough, flexible connective tissue found in various parts of the body including the joints and larynx.

2. Maffulli, N., Longo, U.G., Campi, S., et al. (2010). Meniscal tears. Open Access Journal of Sports Medicine 1: 45–54.

Prognosis

In the short-term, treatment of meniscal tears is usually effective and will allow you to return to your regular activity level within a few weeks or months.

The long-term effect of a meniscal tear depends on your age, and how serious the tear is. Younger people have a better chance of healing than people over the age of 50.

2. Maffulli, N., Longo, U.G., Campi, S., et al. (2010). Meniscal tears. Open Access Journal of Sports Medicine 1: 45–54.