This study aims to evaluate the association of elevated blood glucose and postoperative complications among diabetic patients after surgical treatment of torsional ankle fracture. This was a retrospective study of consecutive diabetic patients treated surgically for a torsional ankle injury between January 2017 and December 2021 at a large tertiary hospital. All patients who met inclusion and exclusion criteria were divided into a high-HbA1c group or a low-HbA1c group according to the HbA1c cutoff of 7.0% within 3 months of operation, then a propensity score match was performed to control potential confounding factors. The primary outcomes were postoperative complications, and secondary outcomes were unplanned secondary procedures. A matched cohort of 238 patients was finally included, with 119 patients with high HbA1c levels and 119 with low HbA1c levels. Patients with high HbA1c levels experienced more complications (31.1% vs 18.5%, P < .01) and more secondary procedures (22.7% and 8.4%, P < .01) than those with low HbA1c levels. Multivariate logistic regression indicated that patients with high HbA1c levels were significantly associated with higher proportions of any complications (OR 2.25, 95% CI 1.08-4.69; P = .03), superficial infection (OR 4.03, 95% CI 2.13-5.41; P < .01), deep infection (OR 1.42, 95% CI 1.23-2.02; P < .01), and any unplanned secondary operations (OR 3.72, 95% CI 1.62-8.52; P < .01) compared with those with low HbA1c levels after controlling for potential confounders. Multivariate linear regression showed that high HbA1c levels were significantly associated with a higher number of complications (β = 4.61, 95% CI 2.63-18.18; P < .01) and a higher number of secondary procedures (β = 4.44, 95% CI 2.79-10.87; P < .01). Patients with an HbA1c >7.0% within 3 months of operation are more likely to have a wound issue/infection and more likely to undergo a secondary procedure after surgical treatment of torsional ankle fractures in diabetic patients than patients with an HbA1c ≤7.0% within 3 months of operation.