Abstract
BACKGROUND: Tillaux-Chaput tubercle fractures occur in adolescents, which are often associated with the separation of the distal tibial growth plate. These types of fractures are rare in adults and even rarer when accompanied by a rupture of the peroneus tertius muscle. Given the limited number of reported cases, there is limited clinical awareness, resulting in missed diagnoses and delayed treatment, ultimately affecting ankle function. CASE PRESENTATION: We report a case of an adult patient who experienced a right ankle injury resulting in swelling and pain after a traffic accident. Initial examination failed to identify the rupture of the peroneus tertius muscle, but the patient was observed to have restricted dorsiflexion and eversion of the foot. Surgical exploration through an anterolateral incision confirmed the rupture and the muscle was then repaired. The patient received four weeks of cast immobilization and then engaged in progressive rehabilitation exercises. DISCUSSION AND CONCLUSION: This report shares the diagnostic and therapeutic experiences of an adult with a Tillaux-Chaput tubercle fracture associated with peroneus tertius muscle rupture to improve clinical recognition of such injuries, thus preventing misdiagnosis and treatment delays.