MANUAL MINORS
Knee locking is a condition where the patient experiences a sudden inability to move or fully extend the knee. It can be caused by mechanical problems, such as a meniscal injury, or by inflammatory conditions.
True locking occurs when a piece of tissue, usually a portion of a torn meniscus, becomes trapped between the joint surfaces, preventing movement. There can also be “false” locking, where severe pain inhibits mobility.
Diagnosis
Diagnosis is based on medical history, locking symptoms, and physical examination. Meniscal tests, such as the McMurray test, may be positive. Imaging, particularly magnetic resonance imaging (MRI), is crucial for identifying the cause of the locking, with meniscal injuries being the most common, although intra-articular loose bodies or osteoarthritis may also be responsible.
Differential Diagnosis
Condition | Key Differentiation |
|---|---|
Meniscal Injury | Pain along the joint line, mechanical locking, clicking during knee movement |
Intra-articular Loose Body | Intermittent episodes of locking, visible on X-rays or MRI |
Knee Osteoarthritis | False locking due to pain and stiffness, radiological evidence of joint wear |
Synovial Plica Syndrome | Intermittent locking with clicking, more common during sporting activities |
Cruciate Ligament Rupture | Instability, joint effusion, and pain, without complete locking |
Emergency Management
In emergencies, initial management of knee locking includes rest, temporary immobilisation, ice application to reduce inflammation, and analgesia with non-steroidal anti-inflammatory drugs (NSAIDs). If there is significant joint effusion, fluid aspiration may be necessary.
The patient should avoid bearing weight on the affected leg. If the locking persists or is accompanied by signs of meniscal injury or severe joint damage, an urgent referral to orthopaedics is needed.
Definitive Treatment
Definitive treatment depends on the underlying cause. For meniscal injuries causing mechanical locking, knee arthroscopy is the treatment of choice to repair or remove the damaged fragment.
In cases of intra-articular loose bodies or advanced osteoarthritis, surgical intervention may also be required. Physiotherapy is essential in the rehabilitation process to restore joint function and prevent recurrences.
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