CLINICAL OUTCOME OF THE USE OF INTRAMEDULLARY NAILS WITH ABSORBABLE ANTIBIOTIC CARRIERS (INAAC)

Aims Infected non-unions can be treated using antibiotic-coated intramedullary nails (IMN), mainly employing PMMA cement. However, there are few reports on outcomes of absorbable antibiotic carriers in confirmed fracture-related infection (FRI), or in high-risk patients. We present a consecutive series of patients treated with IMNs coated with an absorbable ceramic, loaded with antibiotics (INaac). Method Patients with either consensus definition confirmed FRI or high-risk of infection with IM nailing (risk >20%) received an INaac using a standardized technique 1 . The canal was reamed and partly filled with liquid, antibiotic-loaded ceramic, before inserting a standard locked IMN, 1mm smaller than the reamed diameter. Systemic antibiotics were given for 6-12 weeks, based on the deep tissue cultures. The primary outcome was infection-free union after one operation. Secondary outcomes included bone union, infection recurrence and ease of nail removal. Results 61 patients (26 femurs, 26 tibias, 9 ankles) were treated. Mean follow-up was 2.3 years (SD 1.60). 40 patients had confirmed FRI (infected non-unions) and 21 had nailing after prolonged external fixation, bone transport or previous FRI with non-union. Staph. aureus was the commonest pathogen (33%) but 30.6% had polymicrobial infection. Gentamicin was implanted in all 61 patients with 22 also having vancomycin in the ceramic carrier. Infection-free union was achieved in 53/61 (86.9%) after one operation. Infection was eradicated in 56/61 (91.8%) and 56/61 (91.8%) united. 16 patients had removal of their nails without difficulty. In the FRI Group, 34/40 (85.0%) achieved infection-free union after index operation. 3/40 had an aseptic non-union, confirmed by tissue sampling at revision nailing, 3/40 had a recurrent infection (two successfully treated with nail removal and one declined further treatment). 18/21 (85.7%) high-risk patients achieved infection-free union from index operation. Two developed infection (9.5%), successfully treated in one with nail removal, and nail exchange in the other. A further case had surgery for aseptic non-union. 58/61 (95.1%) had infection-free union at final follow-up. There were no amputations. Conclusion Combining absorbable antibiotics with standard trauma nails (INaac) allows safe stabilization of infected non-unions and high-risk fractures in a single stage with high rates of infection clearance and union. This may reduce treatment morbidity by avoiding the use of external fixation or multiple stage surgery.