Higher Rate of Treatment Success of Infected Femoral Shaft Non-unions with Ultrathin Silver-Polysiloxane-Coated Implants.

Abstract

Infected non-union represents a severe complication after femoral shaft fractures, often associated with high recurrence rates and the need for multiple surgical revisions. Antimicrobial implant coatings may improve treatment success; however, evidence on the use of silver as an implant coating remains limited. This study aimed to (1) report short-term outcomes following treatment of infected femoral shaft non-union and (2) investigate if silver-polysiloxane-coating of implants leads to a significantly higher rate of treatment success at one-year follow-up. This prospective cohort study (REFECT) with a historical control group included 70 patients treated for infected femoral shaft non-unions from 2013 to 2024 using either conventional, uncoated (UC, n = 62) or silver-polysiloxan-coated (SC, n = 8) implants with minimum of one-year follow-up. The primary outcome was successful treatment at one-year follow-up, defined as bony consolidation, and full weight-bearing and without recurrent infection. Secondary outcomes included clinical outcomes, blood serum analysis (including silver-ion concentration), radiographic outcomes, and patient reported outcome measures (SC-cohort only) including Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Lower Extremity Functional Scale (LEFS), and EuroQol-Visual Analogue Scale (EQ-VAS). Mean follow-up was 43.9±33.1 months (SC: median (interquartile range), age 39 (27-62); UC: 52 (41-57); 25% female; 40% multidrug-resistant bacteria). The treatment success rate was significantly higher in the SC-cohort at one-year follow-up (SC: 100%, 95% CI 63-100% vs. UC: 61%, 95% CI 48-73%; p = 0.028). The SC-cohort showed a non-significant reduction of length of stay (p = 0.165) and number of operations (p = 0.182), while treatment costs were significantly lower (33886 € vs. 48937 €, p = 0.048). Compared to the preoperative state, the SC-cohort demonstrated improvement in WOMAC (p = 0.183), LEFS (p = 0.097), and EQ-VAS (p < 0.001). Serum silver ion concentration reached maximum 0.014 mg/l without clinical signs of argyria, and all SC-cohort patients had a reduction to normal concentration thresholds at final follow-up. This study presents short-term outcomes following treatment of patients with infected femoral shaft non-unions. Application of a silver-polysiloxane implant coating was associated with a significantly higher rate of treatment success at one-year-follow-up compared to conventional, uncoated implants. Prospective Cohort Study with Historical Control Group, III.