The association of total hip arthroplasty and bladder injury has been well documented. Most cases of fistula formation between the bladder and the hip arthroplasty have occurred, either at the time of hip arthroplasty or subsequently. We report on this rare case where a bladder puncture resulted in infection of the arthroplasty. This occurred through an acetabular floor defect secondary to osteolysis and the subsequent fistula formation.