Clinical utility of antibiotic-loaded hydroxyapatite block for treatment of intractable periprosthetic joint infection and septic arthritis of the hip

Objective. Antibiotic-loaded hydroxyapatite block (AHAB) allows gradual release of antibiotics for long duration without thermal damage and, therefore, is potentially a more effective antibacterial spacer than antibiotic-loaded polymethylmethacrylate cement (ALAC). The purposes of this study are to assess the utility of AHAB for the treatment of periprosthetic joint infection (PJI) or septic arthritis (SA) of the hip and to assess the potency of AHAB and ALAC in vitro. Methods. AHAB was utilized in two-stage reconstruction surgery for 20 PJI and 7 SA patients. Clinical success was confirmed if the patients did not show any sign of recurrence of infection during the follow-up period. Duration and amount of active vancomycin (VCM) released from AHAB and ALAC spacer were investigated in vitro. Results. Two-stage reconstruction using AHAB significantly improved hip function and showed 100% clinical success with mean follow-up of 37 months. The in vitro duration of the active effect of VCM released from AHAB (21 days) was longer than that from ALAC (7 days) and the amount of active VCM released from AHAB was higher than that from ALAC. Conclusions. AHAB promises to release higher amounts of active VCM for longer durations than ALAC; therefore, it is a promising treatment for intractable PJI or SA.