[Periosteum entrapped in growth plate cartilage in patients with epiphyseal fracture-separation: about a case].

Foreign body entrapment in growth plate cartilage is a rare disease. It often occurs in patients with epiphyseal separation. Its diagnosis is radiological, based on brain magnetic resonance imaging (MRI). We here report a case of a 13-year-old girl who presented with a painful left post traumatic knee. The clinical examination and the standard radiographs performed were in favor of a Salter-Harris type 1 epiphyseal detachment. The first-line treatment, which consisted of immobilization in a cast for three weeks, was unsatisfactory. Faced with this therapeutic failure, an MRI was performed and demonstrated an incarceration of a foreign body in the conjugation cartilage. Secondary management was based on surgery, without sequelae.