A femoral artery aneurysm is a very rare complication of hip surgery treatment. In this presentation, we report a rare case of bone destruction caused by the femoral artery aneurysm after a hip hemiarthroplasty operation as a late stage complication. A 77-year-old male patient presented with swelling and pain in the hip without any signs of ischemia. X-ray showed a 7 cm bone destruction in the medial cortex of the proximal femur. After ultrasound imaging, a femoral artery aneurysm was diagnosed. The patient was operated on by vascular surgeons, and a large amount of organized hematoma with artery aneurysm was removed. The diagnosis of femoral aneurysm after hip surgery treatment can be difficult. Femoral aneurysm is rare and usually secondary to trauma, infection, or iatrogenic injury. We assumed that this case occurred during the hemiarthroplasty operation, caused by a compressing effect to the bone causing destruction. The patient was followed for 2 years, during which time the preoperative symptoms reduced dramatically and Harris Hip Score improved. After a hip arthroplasty operation, it must be kept in mind that a femoral arterial aneurysm can cause persistent symptoms. This case illustrates the importance of considering a pseudoaneurysm as a possible cause of periprosthetic osteolysis, particularly if rapid progressive growth has occurred. If this vascular injury had not been correctly diagnosed, the method of treatment could have been much different, probably with catastrophic consequences.