Avascular Necrosis of Proximal Tibia Associated with Pathological Fracture - A Rare Entity - A Case Report.

Introduction: Epiphyseal infarcts are likely to be treated early because most are symptomatic. However, metaphyseal and diaphyseal infarcts are silent and are diagnosed incidentally. Sarcomas developing in the necrotic bone are extremely rare, but they have been reported in literature. Proximal third tibial shaft pathological fracture due to avascular necrosis (AVN) is an extremely rare occurrence.

Case Report: A 56-year-old lady presented with complaints of pain and inability to weight bear over the right leg following an alleged history of trivial trauma while doing household activities. The radiograph showed a transverse fracture at the junction of the proximal third and middle third of the shaft of the tibia. In view of the suspicion of pathological fracture, magnetic resonance imaging of the right leg was done which showed features of AVN. A core biopsy of the lesion was done to rule out tumors considering the risk of malignant transformation. Fixation of fracture was done with intramedullary interlocking nailing of the tibia. The 6-month post-operative follow-up clinical, pathological, and radiological outcome showed complete healing of the fracture. The stabilization of fracture alone without augmentation led to fracture healing.

Conclusion: AVN need not always occur in precarious areas such as the head of the femur, proximal radius, and distal fibula. Rarely, AVN of diaphyseal bone can lead to pathological fracture as illustrated in this case report. Fractures can heal following fixation, but the patient has to be followed up for the rare possibility of malignant transformation.