We report on three patients with a benign cystic lesion of the femoral neck or trochanter. All patients were women between the ages of 19 and 34 years (median, 20 years). The diagnosis was based on X-ray imaging, which showed a solitary bone cyst with a central osteolytic lesion, thinning and inflating the cortex. However the pathological diagnosis was aneurysmal bone cyst. All patients were treated by curettage and an autogenous bone graft with or without hydroxyapatite, in conjunction with a dynamic hip screw, dynamic condylar screw, or a γ nail. At a median follow-up 33 months, all patients had achieved good bony union and incorporation of the implanted graft and packing of the hydroxyapatite. There were no complications and no recurrences. Internal fixation promotes union of the graft to the host bone. A γ nail is useful, because the nail occupies the bony space, making only a small amount of graft bone needed.
