An atypical symptomatic discoid lateral meniscus in a toddler

Meniscal tears and meniscal instability are rare complications of a discoid lateral meniscus in a very young child. We report a case of a 32-month-old male who presented with a limp and limited extension of his right knee. Magnetic resonance and sonographic images demonstrated a discoid meniscus with a posterior horn tear and unstable anterior horn, confirmed by arthroscopy. The patient was treated with saucerization of the lateral discoid meniscus, debridement of the posterior horn tear, and repair of the unstable anterior horn. This case shows a rare complication of variant anatomy that is not well documented in the pediatric radiologic literature, but nonetheless should be considered in the pediatric population.