Total Hip Replacement in Fracture of Hip with Unicameral Bone Cyst - A Rare Case Report.

Introduction: Unicameral (simple) bone cysts (UBCs) are fluid-filled intramedullary cavities commonly seen in the metaphysis of long bones in young patients under the age of 20 years. Pathological hip fractures associated with UBCs in the proximal femur are rare, especially in non-osteoporotic elderly patients. The management of such tumors, such as benign lesions of bone causing pathological fractures at the biomechanically critical load-bearing zone of the neck of the femur, remains a clinical challenge due to limited literature on optimal treatment strategies. Case Report: A 60-year-old non-osteoporotic male presented with right hip pain and inability to walk for 10 days, without any history of recent trauma. X-ray pictures revealed a pathological hip fracture of the right hip in the neck of the femur with an associated lytic lesion with benign radiological appearance. Computed tomography scan confirmed a bony cystic lesion, whereas a DEXA scan ruled out osteoporosis. Oncological workup excluded any metastatic pathology, and the patient was managed surgically with cemented total hip replacement (THR). Intraoperatively, a cystic lesion in the femoral neck was excised and sent for histopathological analysis, which confirmed it to be a unicameral (simple) bone cyst. The patient was mobilized on the first post-operative day and achieved excellent functional recovery, with a Harris Hip Score of 90 at 12 months follow-up. Conclusion: Pathological fractures of the femoral neck due to UBCs are exceptionally rare in elderly patients. This case highlights the successful management of a unicameral bone cyst with cemented THR, demonstrating that THR can be a viable treatment option for pathological hip fractures due to benign bone lesions in older adults.