Bone stress injuries in the presence of tarsal coalition as a cause of hindfoot pain in adolescents: case series of 6 patients with literature review.

OBJECTIVE: To highlight causal relationship between stress fracture in the presence of tarsal coalition and hindfoot pain in adolescents on magnetic resonance imaging (MRI). MATERIAL AND METHODS: A retrospective review was performed of the clinical and MRI imaging findings of 6 adolescents referred for MRI to evaluate symptoms of hindfoot pain with possible tarsal coalition. MRI studies were systematically assessed for cause of hindfoot pain, types of tarsal coalition, patterns of stress fractures, bone marrow oedema and any other associated features. RESULTS: All the 6 patients (4 male: 2 female) aged between 12 and 19 years developed insidious onset of hindfoot or midfoot pain over a period of weeks to months. On MRI, all 6 cases had features of fibrous tarsal coalition predominantly in the calcaneonavicular articulation (5 out of 6 patients). Associated stress fractures/response were in the posterior facet/body of the calcaneus (3), talar head (2), cuboid (1) and third metatarsal bone in one patient. CONCLUSION: Stress fractures/response adjacent to tarsal coalition could be because of altered biomechanics and can be an unusual cause of hindfoot pain in adolescents. A high index of suspicion and complementary MRI findings is crucial to interpret this condition to direct appropriate patient management.