Alerts and Notices
SynopsisCauses / typical injury mechanism: There are generally 2 mechanisms of meniscal injury, traumatic versus degenerative, which have unique presentation patterns. Traumatic tears typically occur in the context of athletics, therefore having a greater prevalence in younger populations, most frequently as a result of planting and twisting motions of the lower leg. The mechanism is not always clear and patients may not recall a specific incident. These injuries often present with intermittent pain along the joint line, sometimes with swelling and effusion. Patients may also complain of locking and catching, as well as popping sensations or the inability to reach full extension.
In contrast, degenerative meniscal tears occur predominantly in older individuals and have a more indolent course. These are not necessarily associated with trauma, often occurring concurrently with osteoarthritis (OA). Pain tends to be more generalized and mechanical symptoms may occur less frequently.
Classic history and presentation: Meniscal tears can generally be described by their location and pattern. The meniscus is classically divided into the anterior, middle, and posterior thirds, as well as the outer, middle, and inner thirds. The latter distribution is more closely associated with meniscal blood supply, with increased vascularity closer to the periphery, and is often stratified into the red-red (outer), red-white (middle), and white-white (inner) tears. Simple tear patterns include longitudinal, radial, horizontal, and oblique, with combinations of multiple patterns classified as complex tears.
Prevalence: Meniscal injuries are one of the most common soft tissue musculoskeletal injuries, thought to account for nearly 20% of those presenting to medical institutions for care. Injury to the medial meniscus is more common than the lateral meniscus.
- Age – The highest proportion of affected patients are between the ages of 20 and 29.
- Sex / gender – This disease primarily affects men over women.
S83.209A – Unspecified tear of unspecified meniscus, current injury, unspecified knee, initial encounter
239720000 – Tear of meniscus of knee
Differential Diagnosis & Pitfalls
- Anterior cruciate ligament (ACL) injury
- MCL injury
- Tibial plateau fracture
- Patellar fracture
- Osteochondritis dissecans
- Plica syndrome
- Discoid meniscus
- Patellofemoral pain syndrome
- Concurrent ligamentous injury can have significant impact on management and outcomes. Any joint laxity on presentation should prompt thorough evaluation of ligamentous structures within the knee.
- Suspicion for fracture should prompt radiographic imaging. Higher energy tibial fractures can result in acute compartment syndrome, which can be a limb-threatening emergency.