ALUMINA CERAMIC ON CERAMIC BEARINGS IN CEMENTLESS TOTAL HIP ARTHROPLASTY. A MINIMUM 10 YEAR FOLLOW UP

Abstract

Aim: Alumina ceramic on ceramic bearings have gained popularity in hip arthroplasty due to the properties of low wear, low friction and chemically inert wear debris. In a previous study, we reported the excellent clinical results of a series of cementless ceramic on ceramic primary total hip arthroplasties at a minimum of 5 years. We now present the follow up results at 10 years.

Method: Between June 1997 and February 1999, 301 consecutive, primary cementless hip arthroplasties were performed on 283 patients in our unit. The mean age of the patients was 57.8 years, with 145 (51%) being female. All of the hips received the same implant: (Osteonic ABC cup and Secure-Fit or Secure-Fit Plus stem; Stryker Orthopaedics). A third generation alumina ceramic on ceramic bearing (Biolox Forte; CeramTec) was used for articulation in all cases. All the operations were performed through a posterior approach with enhanced posterior repair, and the post-operative protocols were the same for all the patients. The clinical and radiographic outcome at 10 years were analysed.

Results: At 10 years, 7.3% had died of unrelated cause and 3% were revised. The average Harris Hip score was 94.3 points at the last follow up. Ninety six percent of patients scored an excellent or good result, with less than 3% have moderate residual pain. Radiographically, all patients assessed had evidence of stable bony ingrowth. There were nine revisions in all, four stem revisions due to periprosthetic fracture, one secondary to aseptic loosening and one to facilitate a femoral shortening osteotomy. There was one cup revision for psoas tendonitis and one for cup repositioning. This same patient subsequently underwent further revision due to acetabular osteolysis with metallosis and some ceramic wear. Overall, the survival rate of the implants was 96% at 10 years. The retrieved femoral heads showed a median wear rate of 0.2 cubic millimeters per year.

Conclusions: Alumina ceramic on ceramic bearings in cementless primary total hip arthroplasty had been shown to have good survival rate at 10 years with good function, low wear rate and no adverse radiographic changes. The one case of osteolysis may be due to ceramic wear debris or may be due to metal wear debris from the neck to rim impingement.