Comparison of Percutaneous Reduction and Pin Fixation in Acute and Chronic Pediatric Mallet Fractures

Background: Although pediatric mallet fractures are more common than adult fractures, no techniques have focused on surgical fixation of pediatric mallet fractures. This study aims to describe the technique and results of percutaneous reduction and fixation in acute and chronic pediatric mallet fractures. Methods: This is a retrospective review of 51 pediatric mallet fractures treated with percutaneous wire fixation from 2007 to 2014; 38 were acute fractures and 13 were chronic (>4 wk from injury). Surgical technique was identical for all fractures: (1) levering the dorsal fragment into its anatomical bed with a percutaneous towel clip; (2) percutanously transfixing the distal interphalangeal joint in slight hyperextension; (3) placing 2 percutaneous kirschner wires, 1 radial and 1 ulnar, from the dorsal epiphyseal fragment to the volar metaphyseal cortex. Outcomes were defined by the Crawford classification. Results: Average age was 14.6 years (range, 11 to 18 y). Mean time from injury to surgery was 16.2 days in the acute group and 50.8 days in the chronic group. Mean joint surface involvement was 50.8% of the articular base with a mean of 2.0 mm of articular gap (acute fractures 1.9 mm, chronic fractures 2.5 mm, P=0.017). Average preoperative extensor lag was 24.6 degrees. Average operative time was 31 minutes for acute fractures and 40 minutes for chronic fractures. Mean length of follow-up was 78.5 days. At final follow-up, all patients healed with an articular gap of 0.2 mm in the acute group and 0.6 mm in the chronic group (P=0.037) with no nonunions or volar subluxations. All patients but 8 (5 acute, 3 chronic) achieved full extension with an average extensor lag of 1.1 degree for the entire cohort. No patient had >10-degree extensor lag at final follow-up. All patients achieved full active flexion of 90 degrees at final follow-up. In the acute group, the Crawford classification was excellent in 87% (33/38), good in 13% (5/38). In the chronic group, results were excellent in 77% (10/13), good in 23% (3/13) (P>0.05). There were no fair or poor outcomes in either group. A clinical dorsal bump was noted in 18% of patients (22% in the acute group, 15% in the chronic group, P>0.05). There were no infections, wire breakages, nail deformities, or unplanned returns to surgery. Conclusions: This percutaneous surgical technique to treat pediatric mallet fractures achieves favorable clinical and radiographic results with minimal complications, even in chronic fractures. Results are better than reported for adult mallet fractures.