Bipolar hemiarthroplasty, a modular system, has been utilized for decades to treat intracapsular fractures of the femoral neck and avascular necrosis of the femoral head. Dislocation is one of the main complications of hip hemiarthroplasty performed for displaced femoral neck fractures. Classic dislocation of the hemiarthroplasty from the native acetabulum occurs in 2.6% of cases. Dissociation between the small head of the prosthesis and the polyethylene insert is an extremely rare complication of bipolar hemiarthroplasty and results in hip dislocation and severe disability. Surgeons must be cognizant of this rare complication and should proceed to open reduction to treat this problem.