Acute meniscus injury
Acute inner and outer meniscus injury / acute medial and lateral meniscus injury/ meniscal tear

There are two semi-circular discs located in the knee, between the upper leg and the lower leg. These are the inner meniscus and the outer meniscus. They can become damaged through acute injury or through aging and wear-and-tear.

Injuries to the meniscus are often seen in combination with an injury to either the cruciate or the knee ligament.

Description of condition

The main function of the menisci is to spread the pressure in the knee joint. The rounded base of the thigh bone (femur) does not fit properly onto the flat top of the lower leg bone (tibia). The inner and outer menisci ensure that both bone parts fit snugly without creating pressure points.

Both menisci also act as shock absorbers and have a proprioceptive role. Proprioception in this case means that the meniscus - as with many other structures in the knee - is able to provide the body with information about the knee's position. For example, we can feel whether the knee is flexed or extended.

If there is an acute meniscus injury, a tear occurs in the inner and/or outer meniscus. This tear can occur in various forms and causes pain when force is applied to the damaged meniscus. This is similar to pushing or pulling on a wound. Sometimes a torn piece of meniscus can lodge in the hinge part of the knee. This may block movement of the knee.

Cause and history

An acute meniscus injury is characterized by a single moment at which the symptoms appear. This usually occurs when the flexed knee is twisted while the foot is on the ground. A snapping sound or sensation may be experienced and the knee will swell after several hours.

If the symptoms occur gradually or through over-exertion, this may indicate a degenerative meniscus injury.

Signs & symptoms

The pain is usually felt on the side of the torn meniscus. Walking up and down steps, crouching and weight-bearing turning movement of the knee are painful. Locking problems can also occur. The knee is suddenly unable to flex or extend fully, because a piece of the meniscus is trapped in the joint.

Diagnosis

There are a number of physiotherapy tests that can confirm a meniscus injury. An MRI may be considered if there is any uncertainty. It is also important to examine other structures in the knee for possible damage.

Treatment

If the tear is not too large it may heal itself without intervention. The physiotherapy treatment is aimed at improving recovery through exercises that stabilize and strengthen the muscles and stimulate proprioception.

Pain, swelling, locking symptoms and a large tear are all indications in favor of surgical treatment. There are many treatment options that can be discussed with the orthopedic surgeon.

Exercises

You can check your symptoms using the online physiotherapy check or make an appointment with a physiotherapy practice in your locality.

References
Brooijmans, F., Huiberts, L., Hekking, J. & Lataster, A. (2011). Kan de fysiotherapeut acute knieletsels adequaat diagnosticeren. Physios: 2011-1-5.
Cleland, J.A. & Koppenhaver, S. (2011). Netter's orthopaedic clinical examination: an evidence-based approach. 2nd ed. Philadelphia: Saunders Elsevier.
Nugteren, K. van & Winkel, D. (2008). Onderzoek en behandeling van de knie. Houten: Bohn Stafleu van Loghum.
Verhaar, J.A.N. & Linden, A.J. van der (2005). Orthopedie. Houten: Bohn Stafleu van Loghum.