A PROSPECTIVE COMPARISON OF ALUMINA CERAMIC AND OXINIUM® TOTAKNEE REPLACEMENT FEMORAL COMPONENTS IN PATIENTS WITH COBALT-CHROME HYPERSENSITIVITY

Abstract

Hypersensitivity to metal alloy orthopaedic implants has become identified increasingly as a cause of implant failure. Because of their hypoallergenic properties, ceramic materials have been recommended as an alternative to metals. Unfortunately, the cost of ceramics and limitations imposed by their material properties has restricted these applications. The metalloceramic composite Oxinium® has been suggested as asubstitute. This is the first study to prospectively compare these materials in patients with documented cobalt-chrome hypersensitivity.

Over a period of ten years, preoperative screening using skin patch testing and in vitro leukocyte stimulation testing of patients with gonarthrosis and a history of metal hypersensitivity identified sixteen patients with allergy to cobalt-chrome alloy. Twelve (all& ) underwent primary, and four underwent revision (3& , 1%) knee replacement surgery using either alumina ceramic femoral components (3 primary, 2 revisions) or Oxinium® femoral components (9 primary, 2 revisions) All implants were fixed with acrylic cement, and all-polyethylenetibial implants were used in each procedure.

None of the patients in the primary groups developed symptoms of allergic reaction at a minimum of one year following surgery. Serial serum antibody and leukocyte stimulation studies have shown no reaction following placement of either type of prosthetic knee. Those undergoing revision surgeries had rapid resolution of preoperative symptoms of pain, effusion and eczematous rash. Serum studies showed a concomitant fall inantibody levels. The two patients undergoing revision surgery with alumina femoral implants subsequently underwent second revisions (both at 8 years) using Oxinium® femoral implants. Neither developed clinical symptoms orchanges in antibody profile.

While the number of patients in the present study is relatively small, it is the only independent, prospective, clinical comparison of these materials. The uniformly good results suggest implants of Oxinium® offer the hypoallergenic properties of alumina without adverse-material properties and at a lower cost.