Sliver sign - patella

Case contributed by Maulik S Patel
Diagnosis certain

Presentation

Knee injury while playing cricket.

Patient Data

Age: 15 years
Gender: Male
x-ray

A small bone fragment close to the medial border of the patella in the axial view. The adjacent medial patellar facet shows a well-defined area of trabecular loss. Associated local soft tissue thickening. No dislocation.

A lytic lesion with a thin sclerotic rim in the lateral distal femur cortex without periosteal reaction.

Case Discussion

The patient presented with acute onset of anterior knee pain while playing cricket. The axial view of the knee shows a bony avulsion from the medial patellar facet. Distal femur cortical lesion shows features of a fibrous cortical defect which is one of the don't touch lesions.

Later MRI (not uploaded) showed transient lateral patellar dislocation, patellar avulsion of the medial patellofemoral ligament, mild ACL posterolateral bundle interstitial edema, and shallow femoral trochlea with patella alta.

MRI report courtesy: Radiologist Dr. Shailesh Padmani.

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