Flexion-Type Supracondylar Humeral Fractures: Ulnar Nerve Injury Increases Risk of Open Reduction.

BACKGROUND: The vast majority of displaced pediatric supracondylar humeral fractures can be treated successfully with closed reduction and percutaneous pinning. The need for open reduction is difficult to determine a priori and is typically due to the failure of closed reduction attempts or persistent limb ischemia. The aims of this study were to determine the prevalence of flexion-type supracondylar humeral fractures, the rate of open reduction for flexion-type fractures, and the predictive impact of ulnar nerve injury on the need for open reduction for flexion-type supracondylar humeral fractures.

METHODS: We developed a database of consecutive pediatric supracondylar humeral fractures treated operatively at a tertiary care pediatric trauma center from 2000 to 2015. Data recorded included age, mechanism of injury, fracture type (open or closed), fracture pattern (flexion-type or extension-type), concomitant skeletal injury, neurovascular injury, treatment, and surgeon. Radiographs of all flexion-type supracondylar humeral fractures were reviewed in order to confirm the classification of the injury pattern. The rate of open reduction for fractures with a flexion-type injury pattern and for such fractures with and without ulnar nerve injury at presentation was assessed.

RESULTS: Of 2,783 consecutive pediatric supracondylar humeral fractures treated by surgeons at our center, 95 (3.4%) were flexion-type fractures. Ulnar nerve injury was noted for 10 (10.5%) of the 95 flexion-type fractures. Open injuries were identified at presentation in 3 (3.2%) of the 95 cases. Among closed fractures, 21 (22.8%) of 92 flexion-type fractures required open reduction compared with 50 (1.9%) of 2,647 extension-type fractures (odds ratio [OR] = 15.4; 95% confidence interval [CI] = 8.8 to 27.0; p < 0.001). Among closed flexion-type fractures, open reduction was performed in 6 (60%) of 10 fractures with associated ulnar nerve injury and in 15 (18.3%) of 82 fractures without ulnar nerve injury (OR = 6.7; 95% CI = 1.7 to 26.7; p = 0.003).

CONCLUSIONS: Among closed supracondylar humeral fractures, the flexion-type injury pattern was associated with a 15.4-fold increase in the odds of open reduction. The presence of an ulnar nerve injury at presentation resulted in an additional 6.7-fold higher risk of open reduction among flexion-type supracondylar humeral fractures. Patients and families should be counseled regarding the high rate of open reduction for flexion-type supracondylar humeral fractures, particularly those with an associated ulnar nerve injury.

LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.