Abstract
Between January 1998 and December 2002, 418 hip revisions were performed. Of these, 45 hips were diagnosed as infected and two-stage revisions were done six weeks apart. These were excluded from the study, leaving 373 revisions for mechanical failure. In 310 cases both components were exchanged, in 59 the acetabular prostheses only and in three the stem only. One permanent resection arthroplasty was done for bone loss. Where necessary bone graft was used liberally. In 83 patients (22%) specimens taken at surgery cultured positive.
A first generation cephalosporin was given as systemic prophylaxis. Routine usage of Gentamycin was reinforced by Vancomycin or fucidic acid in the cement and bone grafts. Double lumen irrigation was inserted in only 5% of cases on the basis of operative findings. Gram stains done intraoperatively in suspected cases were non-contributory. Seventy-six percent of cultures were gram positive, with a preponderance of coagulase negative staphylococcus. Twelve percent were gram negative and 12% were mixed cultures of gram positive and gram negative organisms. One methicillin-resistant Staphylococcus aureus and one fungus were identified. As most of these patients were referred from elsewhere, we did not know whether or not Gentamycin had been used in the cement during previous surgery.
Implant failure due to low-grade infection was under-diagnosed in this series. Because of the relatively low number of failures caused by infection in this group, we recommend, with some improvements, the revision protocol presented. The expense of more detailed preoperative evaluation should be weighed against the success of the protocol.
The abstracts were prepared by Professor M. B. E. Sweet. Correspondence should be addressed to him at PO Box 47363, Parklands, Johannesburg 2121, South Africa.
