Antibiotic Mixing through Impacted Bone Grafts Does Not Seem Indicated in Two-Stage Cemented Hip Revisions for Septic Loosening

Impaction bone grafts (IBG) in two-stage revision for prosthetic hip infection (PHI) might be more susceptible for infection, therefore antibiotic mixing through these grafts has been suggested. However, outcomes have not been compared with IBG without antibiotics and no long-term results are available. Therefore, we evaluated long-term infection-free outcome after the use of IBG without antibiotic supplement in two-stage revision for PHI. Patients were divided into positive (group 1, n = 8) and negative (group 2, n = 28) cultures at re-implantation and followed up to 18 years after re-implantation. Five of 36 patients died from non-orthopaedic causes (median 37, range 24-149 months). Five patients had a re-operation not related to infection (median 39, range 7-140 months). These were censored in the Kaplan-Meier estimator at the last outpatient evaluation. We found an overall re-infection rate of 2.8% within two years, which matches comparative studies in which antibiotic impregnated bone grafts had been used. In group 1, there was one re-infection after 44 months. In group 2, all three infections occurred within 56 months with an estimated infection-free percentage at 10 years of 87% (95% CI 66-96). Follow-up should be extended beyond two years and randomised clinical trials are needed for further comparison with IBG impregnated with antibiotics.