Aims

The primary aim of this independent prospective randomised trial was to compare serum metal ion levels for ceramic-on-metal (CoM) and metal-on-metal (MoM) bearing surfaces in total hip arthroplasty (THA). Our one-year results demonstrated elevation in metal ion levels above baseline with no significant difference between the CoM and MoM groups. This paper reviews the five-year data.

In a double-blinded randomised controlled trial, 83 patients with primary osteoarthritis of the hip received either a ceramic-on-metal (CoM) or metal-on-metal (MoM) total hip replacement (THR). The implants differed only in the bearing surfaces used. The serum levels of cobalt and chromium and functional outcome scores were compared pre-operatively and at six and 12 months post-operatively.

Data were available for 41 CoM and 36 MoM THRs (four patients were lost to follow-up, two received incorrect implants). The baseline characteristics of both cohorts were similar. Femoral head size measured 36 mm in all but two patients who had 28 mm heads. The mean serum cobalt and chromium levels increased in both groups, with no difference noted between groups at six months (cobalt p = 0.67, chromium p = 0.87) and 12 months (cobalt p = 0.76, chromium p = 0.76) post-operatively. Similarly, the mean Oxford hip scores, Western Ontario and McMaster Universities Osteoarthritis index and University of California, Los Angeles activity scores showed comparable improvement at 12 months.

Our findings indicate that CoM and MoM couplings are associated with an equivalent increase in serum cobalt and chromium levels, and comparable functional outcome scores at six and 12-months follow-up.

We report the effectiveness of revision of total elbow replacement by re-cementing. Between 1982 and 2004, 53 elbows in 52 patients were treated with re-cementing of a total elbow replacement into part or all of the existing cement mantle or into the debrided host-bone interface, without the use of structural bone augmentation or a custom prosthesis. The original implant revision was still in situ and functional in 42 of 53 elbows (79%) at a mean of 94.5 months (26 to 266) after surgery. In 31 of these 42 elbows (74%) the Mayo Elbow Performance Score was good or excellent. Overall, of the 53 elbows, 18 (34%) required re-operation, ten (19%) for loosening. A classification system was developed to identify those not suitable for revision by this technique, and using this we have showed that successful re-implantation is statistically correlated to properly addressing the bone deficiency for both the humeral (p = 0.005) and the ulnar (p = 0.039) components.