Non-union after Fracture of the Anterior Tibial Spine in a 6-Year-old Child: A Case Report

INTRODUCTION: Fractures of the tibial spines occur in 3/100,000 children per year and are rare in children under 8 years. Non-union after avulsion fracture of the tibial spine is even rarer, especially under 8 years, with only few cases described in the literature. CASE PRESENTATION: A 6-year-old boy with went to the emergency department after suffering trauma in his left knee. In the performed X-ray, no osteoarticular injury was identified. Conservative treatment with immobilization with cast was performed. After removing the immobilization, the initial evolution was positive with no pain on mobilization. A few months later, he went again to the emergency department due to new left knee trauma. On examination, he had pain in the mobilization of the left knee, especially in knee extension which was not entire. Image study led to the diagnostic of avulsion fracture of the anterior tibial spines. The fracture was classified as modified Meyers and Mckeever Type II and conservative treatment with cast immobilization was performed. In the clinical and imaging revaluation done 4 weeks later, an evolution to non-union of the anterior tibial spine was noticed. At arthroscopy, non-union of tibial spines was confirmed, with elephant paw bone fragment with loss of its right to domicile. Open surgery was performed with debridement, cruentation, and fixation of the bone fragment to the tibia with a screw. The patient had favorable post-operative evolution with fracture consolidation, preserved mobility, no instability of the joint, and no limitation in daily and school activities. Four years after the initial surgery, a second procedure was performed for the removal of the screw. During 7 years of follow-up, no limitations or sequels were found. CONCLUSION: This case illustrates a very rare complication of the fracture of the tibial spine, the non-union, which is very rare under 8 years age. Besides, it highlights the importance of having a high index of suspicion to detect non-union after tibial spine fracture as long as timely treatment may be crucial to avoid definite sequels and disabilities.