Background: Considerable debate exists regarding how soft-tissue edema should influence timing of surgery for ankle and other lower extremity fractures. Assessment of swelling is subjective, and timing varies among surgeons. However, timing of surgery is one of the few modifiable factors in fracture care. Ultrasonography can objectively measure swelling and help determine optimal timing. The purposes of this study were to determine whether objective measures of swelling, timing to surgery, and patient-specific risk factors correlated with wound complications and to try to create a prediction model for postoperative wound complications based on identified modifiable and nonmodifiable risk factors.
Methods: Patients with closed ankle and other lower extremity fractures requiring surgery with an uninjured, contralateral extremity were included. Demographic information and sonographic measurements on both lower extremities were obtained pre-operatively. Subjects were followed for 3 months and wound complications were documented. A predictive algorithm of independent risk factors was constructed, determining wound complication risk. Given that patients with ankle fractures made up the majority of the study cohort (75/93 or 80%), a separate statistical analysis was performed on this group. A total of 93 subjects completed the study, with 75/93 sustaining ankle fractures.
Results: Overall wound complication rate was 18.3%. Timing to surgery showed no correlation with wound complications. A heel-pad edema index >1.4 was independently associated with wound complications. Subgroup analysis of ankle fractures demonstrated a 3.4× increase in wound complications with a heel-pad edema index >1.4. Tobacco history and BMI >25 were independent predictors of wound complications. An algorithm was established based on heel-pad edema index, BMI >25, and tobacco history. Patients with none of the 3 factors had a 3% probability of a wound complication. Patients with 1/3, 2/3 and 3/3 factors had a 12-36%, 60-86% and 96% probability of a wound complication, respectively.
Conclusions: Timing to surgery had no correlation with wound complications. Heel-pad edema index >1.4, BMI >25, and tobacco-use correlated with wound complications. When separately analyzing the cohort that sustained ankle fractures, the heel-pad edema index of >1.4 was still demonstrated to be predictive of wound complications corresponding to a 3.4× increase in wound complication rates (11.1% vs 37.5%). Risk of wound complications significantly increased with each factor. In patients with increased BMI and/or tobacco use, resolution of heel edema may significantly reduce wound complications in lower extremity trauma.
Level of evidence: Level II, prognostic, prospective cohort study.
Keywords: complications; fracture; outcome studies; risk factors; soft tissue; swelling; trauma.