Diagnostic Assessment and Surgical Management of Synovial Chondromatosis of the Midfoot in a 13-Year-Old Child.

Abstract

Synovial chondromatosis (SC), a rare disorder characterized by the formation of cartilaginous nodules and intra-articular loose bodies causing pain, swelling, and mobility issues, most often affects the knee in middle-aged individuals. After having consulted several specialists, a 13-year-old girl presented for rheumatology evaluation of chronic left ankle pain with no history of trauma. She reported daily pain that was worse in the morning. Differential diagnoses included tenosynovial giant cell tumor, chronic synovitis with rice bodies, SC, and juvenile idiopathic arthritis (JIA). Calcified intra-articular loose bodies were visible on plain radiographs that are not characteristic of the rice bodies seen in JIA and strongly favor SC. Based on the patient's history, physical examination, imaging (radiographs and magnetic resonance imaging), and histological analysis, a diagnosis of SC of the talonavicular joint was confirmed. The patient underwent surgical excision; 6 weeks later, she returned for superficial irrigation and debridement for <i>Staphylococcus aureus</i> infection of the surgical wound. At 6 months post-surgical excision, the patient had completed physical therapy and returned to all activities, including sports. The authors present the first known pediatric case of primary SC of the talonavicular joint. This report suggests that diagnosis in a child with atraumatic joint pain and swelling should take into account a variety of conditions, especially if the patient has not responded to typical treatments for JIA. It also underscores the need for careful imaging review. Level V, case report.