Effect of Local Gentamicin Infiltration on Surgical Site Infection Following Lower Limb Open Reduction and Internal Fixation: A Randomized Double-Blinded Trial

Abstract

Background: Surgical site infection (SSI) remains a formidable complication in orthopedic
surgery, particularly in the presence of implanted biomaterials such as plates and intramedullary
nails. While perioperative antimicrobial prophylaxis is standard practice, local antibiotic
infiltration may offer additional protection against infection in open reduction and internal
fixation procedures.
Objective: To evaluate the additive effect of local gentamicin infiltration on the incidence of
surgical site infection following lower limb open reduction and osteosynthesis.
Methods: This prospective, randomized, double-blind, hospital-based interventional study
enrolled 100 patients indicated for open plating or intramedullary nailing of lower limb fractures
or deformities. Participants were randomized into two groups of 50 each: Group A (control)
received 4 mL of normal saline, and Group B (intervention) received 160 mg gentamicin (4 mL)
infiltrated into the surgical wound prior to closure. Both groups received intravenous ceftriaxone
prophylaxis intraoperative and for 72 hours postoperatively. Wounds were drained, and patients
were followed for 90 days. Wound assessment for infection was performed on days 3, 7, 10, 14,
28, and at 6 and 12 weeks using the ASEPSIS score.
Results: Ninety-three patients completed 90-day follow-up (7 lost to follow-up). The majority
were male (74.2%) and aged 26–35 years (37.6%). Traumatic fracture fixation comprised 83.9%
of cases, with femur (47.7%) and tibia (36.6%) as the most common anatomical sites. Plating
was the predominant fixation method (50.5%). The overall infection rate was 11.8%, with 17.4%
in Group A and 6.4% in Group B; however, the difference was not statistically significant (p =
0.120). Significant risk factors for SSI included BMI >25 kg/m² (p = 0.010), operative duration
>3 hours (p = 0.019), and perioperative blood transfusion (p = 0.001). No association was found
with diabetes, hypertension, or ASA class II status. Staphylococcus aureus was the most
frequently isolated organism.
Conclusion: Local gentamicin infiltration was associated with a lower infection rate compared
with placebo, though the difference did not reach statistical significance. Identified modifiable
risk factors—obesity, prolonged operative time, and blood transfusion—warrant targeted
preventive strategies.