Two-stage treatment protocol for isolated septic acetabular cup loosening.

The aim of this study was to evaluate the treatment of isolated septic acetabular cup loosening without involvement of the prosthesis stem by insertion of an antibiotic-loaded spacer head and stem retention. Between 1999 and 2008, 13 patients (5 men, 8 women, mean age 69 years) were treated according to this regimen. S. epidermidis and S. aureus were the two most commonly identified pathogens. In 12 cases the polymethylmethacrylate spacers were impregnated with 0.5 g gentamicin + 2 g vancomycin per 40 g bone cement, except in one patient with vancomycin allergy, in whom 0.5 g gentamicin + 0.4 g teicoplanin were used. The spacers acted as hemiarthroplasties. The mean spacer head implantation time was 88 (35-270) days. At a mean follow-up of 55 (12-83) months, infection eradication was achieved in 11 out of 12 cases (91.6%). Complications included a draining sinus, and one spacer and one definitive prosthesis dislocation. One patient died after reimplantation due to cardiopulmonary decompensation.