Abstract
Calcium sulphate is now a proven adjunct to the replenishment of bone stock in joint replacement surgery. Alone and as a composite, it has been used successfully for many years in both dental and orthopaedic applications. OsteoSet (Wright Medical Technology), a processed, purified material, has been used as a bone void filler in 51 revision total hip arthroplasty (THA) procedures.
Follow-up of these cases ranges from 3 to 48 months. Radiographs show that the calcium sulphate has disappeared in all cases. In all but three patients, all of whom had failure of the acetabular component or infection, the calcium sulphate has been replaced with what appears to be trabeculated cancellous bone. Clinical results for cases that did not have mechanical failure or infection are indistinguishable from any revision THA in which the acetabular component is well fixed.
Implantation of the calcium sulphate pellets calls for preparation of a well vascularised bed. The pellets are placed in such a way that load is not transferred to them from the implanted acetabular component. Rather, the load should be transferred from the acetabular component directly to host bone. Postoperatively, load bearing is limited for at least eight weeks and for longer of the quality of the supporting bone is poor.
The abstracts were prepared by Professor M. B. E. Sweet. Correspondence should be addressed to him at The Department of Orthopaedic Surgery, Medical School, University of Witwatersrand, 7 York Road, Parktown, Johannesburg, 2193 South Africa
