VANCOMYCIN-LOADED HYDROXYAPATITE-BASED BONE SUBSTITUTES IN FRACTURE-RELATED INFECTION AND OSTEOMYELITIS: A PROSPECTIVE COHORT STUDY OF 58 PATIENTS

Introduction and aim Gentamicin-loaded bone substitutes are widely used in the treatment of fracture-related infection (FRI) and osteomyelitis (OM), achieving cure rates of around 80% or higher, partly due to their broad antimicrobial spectrum. However, there is limited evidence regarding the use of vancomycin-loaded bone substitutes, either as monotherapy or in combination with gentamicin, in this setting. The aim of this study was to evaluate cure rates, as well as clinical and radiological outcomes, in patients with FRI and OM treated with bone substitutes loaded with vancomycin alone or in combination with gentamicin. Materials and Methods This is a prospective descriptive study including patients treated for FRI and OM between 2019 and 2023 using bone substitutes (calcium sulfate and hydroxyapatite) loaded with vancomycin. FRI was defined according to the criteria proposed by Metsemakers et al. The primary outcome was infection control, defined as the absence of fistula, the need for suppressive antibiotic therapy, additional surgical interventions, or infection-related death, with a minimum follow-up of 2 years. Secondary outcomes included radiological results (degree of bone healing) and quality of life assessed using the EQ-5D questionnaire. Results A total of 58 patients were included (43% female), with a mean age of 50 years and a mean BMI of 28 kg/m 2 . FRI accounted for 72% of cases, with the distal tibia being the most common location (40%). According to the BACH classification, the most frequent categories were B2 (62.07%), A1 (58.62%), C1 (79.31%), and H2 (53.45%). The most commonly performed surgical techniques were debridement with implant removal (39.66%) and debridement, with or without removal of the implant, followed by reimplantation of new hardware (20.69%). The most frequently isolated microorganisms were polymicrobial infections and methicillin-sensitive Staphylococcus aureus (MSSA), both accounting for 24.14% of cases. Radiological consolidation was observed in 89.65% of patients. The overall cure rate was 79.31%, and the mean EQ-5D score was 0.637. Conclusion The use of calcium sulfate and hydroxyapatite bone substitutes loaded with vancomycin, alone or in combination with gentamicin, appears to be an effective option for dead space management in the treatment of FRI and OM, particularly in infections caused by Gram-positive organisms, with infection control rates comparable to those reported for gentamicin-loaded substitutes.