Association Between Hypothyroidism and Postoperative Complications Following Operative Ankle Fracture Fixation: A Retrospective Cohort Study.

BACKGROUND

Hypothyroidism has been associated with altered bone metabolism, impaired mineralization, and increased fracture risk, but its relationship with postoperative complications after operative ankle fracture fixation remains poorly defined. This study evaluated whether preexisting hypothyroidism is associated with increased complications following surgical treatment of ankle fractures.

METHODS

Adults undergoing operative ankle fracture fixation or related ankle fracture surgery in TriNetX were stratified by hypothyroidism diagnosed within 6 months before or on surgery vs no recorded hypothyroidism history. Propensity score matching was performed 1:1 using demographic factors, diagnosis-coded obesity/overweight, hemoglobin A1c, tobacco-related variables, diabetes, chronic kidney disease, cardiovascular disease, chronic obstructive pulmonary disease, peripheral vascular disease, and osteoporosis. No single primary outcome was designated; all 6 outcomes were assessed on an equal, exploratory basis at 3 months, 6 months, and 1 year.

RESULTS

After matching, 10 406 patients per cohort were included in the 3- and 6-month analyses, and 10 407 per cohort were included at 1 year. With the numbers available, no significant difference could be detected for any 3-month outcome. At 6 months, nonunion/malunion (RR, 1.305; 95% CI, 1.065-1.600; RD P = .010) and hardware failure (RR, 1.302; 95% CI, 1.058-1.602; RD P = .013) were higher in hypothyroid patients. At 1 year, nonunion/malunion (RR, 1.407; 95% CI, 1.166-1.698; RD P < .001) and hardware failure (RR, 1.264; 95% CI, 1.065-1.500; RD P = .007) remained higher. Infection, hardware removal, wound dehiscence, and broad procedure-related complications were not significant at any time point.

CONCLUSION

In this propensity-matched retrospective cohort study, preexisting hypothyroidism was associated with modest but statistically significant increases in delayed osseous and hardware-related complications after operative ankle fracture surgery (P < .05 for both outcomes at 6 months and 1 year). These findings should be interpreted as associative and warrant prospective validation.

LEVEL OF EVIDENCE: Level III, retrospective cohort study.