Presentation
Mum noticed a painless lump at the anterolateral knee on flexion. No history of trauma or penetrating injury.
Patient Data
Age: 20 months
Gender: Male
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The palpable lump was examined, revealing a 5 x 3 mm hypoechoic soft tissue mass inferolateral to the patella. This reduced on knee extension, through a 3 mm defect in the lateral patellar retinaculum. Anteriorly, the iliotibial band was intact to Gerdy's tubercle; posteriorly the lateral collateral ligament was intact to the fibular styloid.
Case Discussion
Findings are consistent with infrapatellar fat pad herniation through a defect in the lateral patellar retinaculum.