The meniscus is an important shock absorbing elastic tissue in our knee joint. Each of us has a medial (inside) and lateral (outside) meniscus. The function of the meniscus includes:
- Shock absorption
- Improve stability of the knee
- Increase the contact area of the knee to reduce stress
In the younger patients, meniscus is usually damaged in sporting injuries during twisting motion of the knee. In the elderly, the meniscus is usually torn as part of the degenerative process of ageing.
The meniscus inherently has a very poor blood supply. Without the nutrients in the blood, the meniscus usually does not heal spontaneously.
Meniscus injury is usually torn by a knee injury that is associated with knee pain and swelling. The swelling of the involved knee joint usually develops over a few hours as opposed to the anterior cruciate ligament which tends to develop immediately. The pain may be localised to the medial (inside) or lateral (outside) of the knee depending on the site of the tear. The patient may also develop mechanical symptoms.
- Medial or lateral knee pain
- Delayed swelling
- Clicking sensation
- Locking of the knee
Locking of the knee occurs when a piece of the torn meniscus gets caught in between the femur (thigh bone) and tibia (calf bone), leading to a jammed knee. The patient will not be able to fully straighten the knee. At times, the patient may need to do certain manoeuvres to unlock the knee. Locking of the knee should be treated urgently.
X-rays and magnetic resonance imaging (MRI) of the knee should be performed to confirm diagnosis. X-rays of the knee is quite normal in patients with meniscus injury. MRI would usually be indicated to confirm clinical diagnosis of meniscus injury and to evaluate for other injuries such as cartilage injury and ligaments injury. MRI is radiation-free and has a very high detection rate.
The treatment for meniscus injury should be individualised according to:
- patient demographics
- associated injuries
All patients with meniscus injury should undergo a course of physiotherapy, rest and anti-inflammatory medications.
Patients with locking of the knee are strongly recommended for arthroscopic (keyhole) knee surgery. Young patients with clicking or persistent pain should also undergo keyhole knee surgery. Associated injuries such as ligament injury or cartilage damage can be treated at the same surgery.
The meniscus can be repaired or partially debrided (trimmed off). The surgical decision depends on the quality of the torn meniscus and location of tear. Your orthopaedic surgeon will discuss in detail regarding the pro and con for each option. Both options would be performed by knee arthroscopy techniques (keyhole surgery). The surgery will be performed under general or regional anaesthesia. The surgery will take about 45 min to one hour. You can be discharged on the same day or be warded overnight. You may have to use crutches depending on your injuries and surgery. After surgery, you will need physiotherapy for about 3 to 6 months. Your surgeons will review your condition regularly after surgery to make sure your recovery is on track.