Low incidence of fl exion-type supracondylar humerus frac-tures but high rate of complications

Background and purpose — Supracondylar humerus fractures are the most common type of elbow fracture in children. A small proportion of them are fl exion-type fractures. We analyzed their current incidence, injury history, clinical and radiographic fi nd- ings, treatment, and outcomes. Patients and methods — We performed a population-based study, including all children < 16 years of age. Radiographs were re-analyzed to include only fl exion-type supracondylar fractures. Medical records were reviewed and outcomes were evaluated at a mean of 9 years after the injury. In addition, we performed a systematic literature review of all papers published on the topic since 1990 and compared the results with the fi ndings of the cur- rent study. Results — During the study period, the rate of fl exion-type fractures was 1.2% (7 out of 606 supracondylar humeral frac- tures). The mean annual incidence was 0.8 per 105. 4 fractures were multidirectionally unstable, according to the Gartland- Wilkins classifi cation. All but 1 were operatively treated. Reduced range of motion, changed carrying angle, and ulnar nerve irrita- tion were the most frequent short-term complications. Finally, in the long-term follow-up, mean carrying angle was 50% more in injured elbows (21°) than in uninjured elbows (14°). 4 patients of the 7 achieved a satisfactory long-term outcome according to Flynn’s criteria. Interpretation — Supracondylar humeral fl exion-type frac- tures are rare. They are usually severe injuries, often resulting in short-term and long-term complications regardless of the original surgical fi xation used.