Overview of acute medial meniscal injuries
- Acute medial meniscal injury can be associated with an acute injury in a young person or chronic degenerative disease in an older person (often associated with osteoarthritis of the knee).
- Diagnosis is clinical and investigations are not usually required.
- Initial management should involve the POLICE regimen [NB2] and analgesia.
- Surgery is usually not recommended.
NB1: This list is a summary guide only; refer to full text.
NB2: POLICE = Protection, Optimal Loading, Ice, Compression, Elevation.
The menisci, or semilunar cartilages, of the knee are crescentic fibrocartilaginous structures attached to the periphery of the articular surfaces of the lateral and medial tibial condyles. Thicker at the periphery, they allow for greater congruence between the rounded femoral condyles and the relatively flat upper surface of the tibia, thereby increasing joint stability.
Meniscal injuries in the knee can be caused by acute or degenerative processes and the management differs for both. Acute meniscal injuries are more likely in younger people (ie under 45 years of age) and differ in pathophysiology from degenerative meniscal injuries that occur in older people (ie 45 years and older). Degenerative meniscal disease can be viewed as part of the disease process of osteoarthritis. For an older patient with a suspected meniscal tear, follow the management advice in the separate topic Degenerative meniscal tears.
Among younger people, the medial meniscus is damaged more frequently than the lateral meniscus. The most frequent mechanism of injury is a rotatory force applied to a semiflexed, weightbearing knee. Acute medial meniscal injury and medial collateral ligament (MCL) sprain are frequently associated with anterior cruciate ligament (ACL) tears.
Small acute meniscal tears may cause minor delayed symptoms and often resolve quickly and spontaneously. More significant tears are associated with immediate pain and restricted range of motion at the knee. Sometimes people describe other mechanical issues such as locking or catching of the knee joint.