Locked knee is characterized by the inability of the patient to extend the knee. The most common cause for obstruction is bucket handle tears of the meniscus 1. Other causes for obstruction include cruciate ligament stumps, osteochondral fractures, synovial plicae, loose bodies and gouty tophi 2,3. This condition needs to be treated urgently as if left untreated, it can lead to flexion deformity of the knee and can create an increased focal stress point over the knee joint leading to cartilage damage and osteoarthritis.
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Clinical presentation
Patients present with an inability to fully extend the knee. On clinical exam swelling may be present, and specific exam maneuvers may elicit ligament damage.
Radiographic features
MRI
Can be useful in identifying the underlying cause of a locked knee; looking for meniscal tears, cruciate ligament injuries, loose bodies, or osteochondral fractures.
Treatment and prognosis
This condition is usually treated arthroscopically to address the underlying cause for the obstruction 1.