Do preoperative glucose levels predict risk of complications in orthopaedic surgery?

Purpose: Post-operative hyperglycemia is a known risk factor for post-surgical complications. The predictive value of pre-operative blood glucose levels, however, is less understood. This study aimed to determine if pre-operative screening blood glucose levels affect the rate of post-operative infection or wound complications. We also investigated if case urgency or anatomic location alters this relationship. Methods: A single-institution retrospective chart review was performed to evaluate patients treated between 2018 and 2021. Subjects ≥ 18 years with closed, non-infected orthopaedic diagnoses requiring surgery were included. Case urgency, demographics, comorbidities, blood glucose level within twelve h prior to surgery, and hemoglobin A1c level within 3 months of surgery, were collected. Infections and wound complications were recorded as outcomes. Results: A total of 775 subjects with a mean age of 61 (range 18–96) were identified, including 543 elective and 232 trauma patients, with a mean pre-operative fasting glucose value of 127.7 mg/dL (range, 49–388 mg/dL) and average HbA1c of 6.9%. The odds of infectious complications were increased by a factor of 1.01 for every 1-point increase in blood glucose (95% CI 1.01–1.02; p < 0.01). Conclusions: Pre-operative blood glucose levels greater than 137 mg/dL were associated with an increase in wound complications, but not deep infections. Infection rates stratified by anatomic site and case urgency were not impacted by pre-operative glucose levels. The increased risk of poor wound healing in patients with pre-operative hyperglycemia demonstrates that day of surgery point-of-care blood glucose screening can be a useful risk stratification tool.