Antegrade Flexible Nailing for Pediatric Metaphyseal-diaphyseal Junction Distal Radius Fracture, is it Safe?

Fractures involving the distal radius metaphyseal-diaphyseal junction (MDJ) present a unique challenge for pediatric orthopedic surgeons. These fractures are too proximal for percutaneous K -wire fixation and too distal for retrograde flexible nailing. The purpose of this study was to: (1) determine the safety of a described antegrade approach from the posterior interosseous nerve (PIN); (2) assess the efficacy of antegrade nailing in cases of distal MDJ fractures; and (3) describe a standardized lateral approach to the proximal radius. A cadaveric study was performed using 10 adult forearms. Anterograde flexinail was introduced at the proximal radius based on the described "safe zone". Distal MDJ fractures were created using osteotomes. We evaluated the distance between the entry point to the PIN in addition to the quality of the reduction for the fracture. The average distance between the entry point and piercing instrument to the PIN was 5.4 cm (range: 4.7 to 6.0 cm). When grouped based on sex, the average distance was significantly further for males (5.8 cm, range: 5.2 to 6.0 cm) versus females (4.9 cm, range: 4.7 to 5.2 cm), P =0.004. Fracture reduction was not maintained after the introduction of the antegrade flexible nail across the fracture site. For all specimens, >25% displacement was seen on the anterior-posterior imaging. Our modified lateral approach to the starting point in the proximal radius is safe as long as the entry point for antegrade flexible nailing stays proximal to the radial tuberosity during the lateral approach to the proximal radius while the elbow is flexed and the forearm pronated.