ONE-STAGE NON-CEMENTED REVISION OF SEPTIC KNEE ENDOPROSTHESIS USING ANTIBIOTIC-LOADED BONE GRAFT

Abstract

Infection of total knee replacement (TKR) is considered a devastating complication, which necessitates complete removal and thorough debridement of the site. Usually long term antibiotic treatment and a multitude of surgical interventions within a period of several months are required until a definitive supply can be achieved. Osseous defects are common in such conditions and need to be addressed during re-implantation. Managing removal, debridement, reconstruction and re-implantation within a single operation is the ideal solution, both for the patient and the treating team, but rarely executed due to the fear of re-infection. Allograft bone may be impregnated with high loads of antibiotics using a special incubation technique. The resulting antibiotic bone compound (ABC) provides high and long lasting antibiotic levels at the site of infection and is likely to restore bone stock. We have investigated the results of one-stage exchange of infected TKR using ABC together with uncemented implants.

Between 1998 and 2004 nineteen exchange procedures of infected TKRs were performed in a single stage, all of them without the use of bone cement. After removal of the implants and radical debridement bone voids were filled with ABC using a modified impaction technique. Consequently, new uncemented implants were inserted. We mainly used the revision type of the LCS knee (DePuy, J& J) as long as ligamentary stability was considered sufficient. Otherwise, we used a custom-made uncemented version of the LINK Rotational Endo Model. Joints were drained and closed immediately; rehabilitation did not differ from uninfected revision.

One knee required re-revision because of persisting infection. The remaining 18 patients stayed infect-free for a period between 2 and 8 years after surgery. In two knees loosening was found after one year, once of the tibial and once of the femoral component. Both were found infect-free at the time of re-revision. All could be successfully revised using the same technique again. No adverse side effects could be found. Incorporation appeared as after grafting with unimpregnated bone grafts.

Using antibiotic-impregnated allografts eradication of pathogens, grafting of defects and re-insertion of an uncemented prosthesis may be accomplished in a one-stage procedure. Since the graft gradually is replaced by healthy own bone, improved long-term results may be expected as well as improved conditions in the case of another revision.