Abstract
Purpose: In 1988, metal-on-metal bearing surfaces were reintroduced in hip replacement surgery with a 28 mm diameter femoral head. These bearings have potential advantages such as improved durability, absence of polyethylene particles and no secondary periprosthetic osteolysis. Tribological studies suggest that larger metal-on-metal articulations would produce less wear than smaller diameter components. But recent clinical studies revealed increased release of circulating ions in metal-metal hip resurfacing compared to 28 mm metal-metal articulation. The aim of the present study is to describe whole blood Chrome and Cobalt ions concentration after non-cemented metal-metal total hip arthroplasty (THA) and hybrid metal-metal surface replacement arthroplasty (SRA).
Method: All patients eligible for the study were randomised to receive uncemented THA or a hybrid SRA. Whole blood samples were collected pre-operatively, at three, six months and one year post operatively. Chrome and Cobalt concentration were measured using a spectrophotometer.
Summary of Results: Blood samples have been taken from 78 patients and are pending analysis.
Discussion: Considering the influence of activity level, weight, time after surgery, the renal function, etc. on the wear behaviour of bearing surfaces, a prospective randomised study is important to obtain a valid comparison. To our knowledge, this is the only randomised study comparing whole blood ions concentration in metal-metal THA and SRA.
Significance: We strongly believe that this subject warrants special attention considering the possible toxicity associated with high levels of circulating metal ions.
Theses abstracts were prepared by Professor Roger Lemaire. Correspondence should be addressed to EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
