Our Specialist Physicians: R. B. Zann, MD
E.T. Shapiro, MD
E. Handal, MD
     
Edgar G. Handal, MD

Total Hip Recall


Edgar G. Handal, M.D.

Recently I have received many calls and questions from patients and journalists about the recall of total hip replacement parts. Understandably, patients have been concerned particularly those who have already had implantation of metal and plastic components which constitute the classic hip replacement. While concern is present, this problem has been limited to one supplier of total hip implants and is not a problem presented by other major suppliers. Sulzer Medica, the company in question, is a respectable company that has faced some recent bad luck as a result of the manufacturing process in their Inter-Op hip shell. However, I would first like to reassure my total joint patients, past and present, that I have not used this particular hip implant for their surgeries.

To explore the problem further requires an understanding of hip implantation. The two main components that make up a total hip implant are the acetabular component which is the shell that is implanted into the upper part of the hip called the acetabulum. The femoral stem is implanted into the thigh bone after removing the bone marrow in the upper portion of the thigh bone. In a cementless application, which is the most common mode of implantation of an acetabular cup, the permanent fixation of the cup relies on the firm fixation of the cup to the socket. Moreover, the surface of the acetabular shell is coated with a special metal that has a rough surface which allows the bone of the acetabulum to grow into the shell, thus forming a single unit contiguous with the patient's own body. Failure of this acetabular shell to bind to the bone and for the bone to grow into the shell will result ultimately in loosening of the acetabular shell requiring revision of this component of the replacement. Similar events can take place on the femoral side resulting in loosening of the femoral component. The process of ingrowth of bone into these specialized hip replacement parts requires a minimum of six weeks time.

Recently Sulzer Medica discovered that a small number of the many implant parts that they manufacture may have a trace of oily lubricant residue on the surface that was not completely removed during the manufacturing process. This residue appears to retard an integrated bond formation with the shell. Reported symptoms include severe groin pain and inability to bear weight on the affected leg. These symptoms are caused by the loosening of the shell from the acetabular bone. This prompted a global recall of the affected parts by this implant company.

At this point a little over one hundred patients have had their defective parts surgically removed and replaced. Most of the patients with the recalled parts are in California, Texas, Arizona, and Florida. Sulzer has alerted the Federal Food and Drug Administration to the problem and has promised to cover costs that patients incur for more medical attention or a second operation.

Despite my large referral basis for revision total hip and knee surgery, I am happy to report that so far I have not seen many patients requiring revision for this problem. It does not appear that every patient that had this cup implanted will require revision and we are studying on a case-by-case basis those patients who have had the implant with routine follow-up to make sure that if any signs of loosening occur appropriate intervention will take place expeditiously. While this was an unfortunate occurrence, we should not lose sight of the fact that without the commitment to research and development made by many companies such as Sulzer Medica, many patients would still suffer from crippling arthritis and never regain the mobility they once enjoyed in their younger years. Patients should not be discouraged from going forward with total hip arthroplasty since 98% to 99% of all patients undergoing total hip replacement are having successful and excellent results even ten years after their initial operation. While this is a significant bump in the road for the advancement of total hip replacement, I feel its effects will be limited and dealt with appropriately. Certainly it does not shake my belief in the wonderful merits of total joint implantation.

(For your information, Dr. Handal uses the Howmedica-Osteonics Exeter Total Hip Replacement System originating in Exeter, England. Ninety percent of the patients implanted with this hip system thirty years ago are still enjoying successful results.)