Dose-Response Association Between Cerclage Wire Number and Infection Risk

Overview

The purpose of this dual-center retrospective study is to investigate the relationship between the number of metallic cerclage wires used in femoral fracture surgery and the risk of developing deep infections. Cerclage wiring is a common technique used to hold bone fragments together during the fixation of complex thigh bone (femur) or hip replacement-related (periprosthetic) fractures. While these wires provide mechanical stability, adding foreign material to the body may increase the risk of bacterial colonization and biofilm formation. Researchers reviewed the medical records of 148 patients treated between 2015 and 2025 at two Level I trauma centers. Patients were divided into three groups based on the "implant burden": those with 1 wire, 2 wires, or 3 or more wires. The study evaluated two main complications: Persistent wound drainage (PWD): Continued fluid leakage from the surgical site for more than 5 days. Deep infection: Serious infections involving deep tissues or the bone that require additional surgery or long-term antibiotics. The results showed a significant "dose-dependent" link, meaning that as the number of wires increased, the risk of drainage and infection also rose significantly, regardless of the length of the surgery. The study suggests that surgeons should use the minimum number of wires necessary to maintain stability to reduce these biological risks.

This dual-center study evaluates the biological impact of "implant burden" in femoral fracture fixation, specifically examining whether the risk of surgical site infection (SSI) is dose-dependent on the number of cerclage constructs used. While cerclage wiring is a recognized adjunct for achieving anatomical reduction in complex subtrochanteric and periprosthetic fractures, the cumulative surface area of multiple braided cables may provide a protected niche for bacterial attachment and biofilm formation. Surgical Protocol and Intervention: All procedures were performed or supervised by fellowship-trained orthopedic trauma surgeons using a "biological fixation" strategy to prioritize the preservation of periosteal blood supply. For femoral shaft and subtrochanteric fractures, metallic cerclage wires or cables were applied via small accessory incisions or through direct lateral approaches. Monofilament wires were secured with symmetric twist knots, while multifilament braided cables were tensioned to 40-50 kg and secured with swaged crimp mechanisms. The cohort was stratified into three groups based on the final construct count verified by postoperative radiographs: Group I (1 wire), Group II (2 wires), and Group III (≥3 wires). Clinical and Laboratory Monitoring: Patients were monitored preoperatively and postoperatively (Days 1, 3, 7, 14) for inflammatory markers, including C-Reactive Protein (CRP) and Erythrocyte Sedimentation Rate (ESR). Nutritional status was assessed via serum albumin levels on the first postoperative day. Wound complications were tracked, with persistent wound drainage (PWD) defined as drainage lasting more than 5 postoperative days. Statistical Modeling: To isolate the independent effect of cerclage count from potential confounders, a penalized (Firth) multivariable logistic regression model was utilized. This approach was selected to reduce small-sample bias and overfitting given the limited number of deep infection events. The core model adjusted for operative duration (continuous and \>120 minutes), postoperative hypoalbuminemia (\<3.0 g/dL), and fracture category (shaft, subtrochanteric, or periprosthetic). Infection-free survival across the three groups was estimated using the Kaplan-Meier method with log-rank (Mantel-Cox) comparisons.