Sliver sign (patella)
The sliver sign refers to a curvilinear intra-articular osteochondral fragment in the knee joint on conventional knee radiographs. In the context of acute knee trauma and in association with joint effusion this sign is highly predictive of a recent transient lateral patellar dislocation 1.
The free osteochondral fragment originates from either the lateral femoral condyle or the patella.
While it can be visible on routine frontal or lateral radiographs, the sliver of bone is most frequently seen on a dedicated patellar view. In about 25% of cases this view is the only view demonstrating the sliver sign 1.
Treatment and prognosis
It is important to recognise this hallmark of transient dislocation as recurrent dislocation can result in additional injury to cartilage and ligaments. Prompt recognition of the sliver sign also results in timely referral to an appropriate specialist and prevents premature return to sports.