Increasing numbers of patients are undergoing revision surgery. The most frequent cause of failure of a total hip replacement is loosening of the implant in bone which may be caused or aggravated by the wear process. The magnitude of the surgery depends on the complexity of prosthetic removal and restoration of bone deficiency. Revision of a surface replacement is likely to be less formidable because the femur or thigh bone is intact. Revision surgery may require bone grafts from your pelvic area and/or from the bone bank. Custom prostheses may be needed. Like primary surgery, the durability is dependent upon the techniques utilized and revision surgery is technically more difficult although quality results can be achieved. Third and fourth revisions have also been performed. Once again, each revision may have special and more difficult challenges for the surgeon and the patient. Special precautions are mandatory following these types of procedures.