Meniscal injuries

Mechanisms of injury

Meniscal injuries rarely occur on their own. As a rule, they are the consequence of injuries associated with high physical activity (e.g., in sports). Two main mechanisms are distinguished in which the menisci are injured in combination with ligaments:

• Sudden flexion, abduction, and external rotation of the lower leg with a fixed foot (characteristic of alpine skiing, ice hockey). This leads to the formation of the so-called "unhappy triad" — the simultaneous rupture of the medial meniscus, tibial collateral ligament (TCL), and anterior cruciate ligament (ACL).
• Extension, adduction, and internal rotation of the lower leg. This mechanism damages the medial meniscus, TCL, ACL, and may also cause a compression fracture of the lateral tibial condyle.

Concomitant hemarthrosis

Meniscal tears, like any injury to intra-articular structures, are often accompanied by hemarthrosis — an accumulation of blood in the joint cavity.

It is important to understand that hemarthrosis is a symptom, not a diagnosis. The presence of even a small amount of blood irritates the synovial membrane, leading to the formation of inflammatory effusion and the development of traumatic synovitis. At the same time, the fluid stretches the capsule, sharply increasing intra-articular pressure, which causes severe pain. To accurately diagnose the nature of the fluid (blood, effusion, or a mixture of both) and reduce pressure, joint aspiration (puncture) is performed.

Diagnostic difficulties

In the acute period of trauma, clinical diagnosis (e.g., performing joint stability tests) is extremely difficult due to pronounced pain syndrome, muscle spasm, and hemarthrosis.

In addition, performing functional tests is strictly contraindicated prior to X-ray examination to avoid worsening the condition in case of potential intra-articular fractures. Therefore, in the first hours and days after the injury, instrumental methods are used to confirm the diagnosis of meniscal and ligamentous injuries: magnetic resonance imaging (MRI) and arthroscopy.

Conservative treatment and the role of muscles

Upon injury to intra-articular structures (menisci, cruciate ligaments), the joint loses part of its stability. Under these conditions, a crucial role is assumed by active stabilizers — periarticular muscles.

Knee injuries often lead to rapid muscle hypotrophy, which can mimic joint instability even with intact ligaments. Properly prescribed physical therapy (PT) aimed at strengthening the muscular framework can compensate for mild degrees of instability, which is often a decisive factor when choosing a conservative treatment strategy.

Briefly: answers to topical questions

Class and exam questions

What else to study on this topic

• Classification of knee joint instability (simple, complex, combined)
• Lachman test and "drawer" signs
• Functional tests in the frontal plane (abduction and adduction stress tests)
• Degrees of compensation for chronic joint instability
• Features of performing comparative functional radiographs

Other topics in the "Specialized Adult Traumatology" section

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