K-Hammer Percutaneous Fixation: A Novel Strategy to Prevent Iatrogenic Ulnar Nerve Injury in Pediatric Supracondylar Fractures

Background: This study assessed the therapeutic efficacy of a novel approach combining percutaneous Kirschner wire fixation with the K-hammer technique in pediatric patients with supracondylar humeral fractures. Methods: This retrospective cohort study enrolled 34 pediatric patients (male: 13 (38.24%); female: 21 (61.76%): 12; age 5.82 ± 2.54 years) with acute flexion-type supracondylar humeral fractures (diagnosis ≤7 days post-trauma). Under general anesthesia, all fractures underwent fluoroscopically guided closed reduction followed by percutaneous fixation: two lateral-entry 1.5–2.0 mm Kirschner wires established initial stabilization, supplemented by a third medial Kirschner wire deployed via the K-Hammer reduction technique to create a biomechanically optimized cross-pinning construct. Postoperatively, the elbow was maintained in a 90° functional position via long-arm fiberglass casts for 4 weeks. Results : During a mean follow-up period of 12.24 ± 4.45 (range: 6–23 months), functional outcomes assessed via Flynn's criteria demonstrated excellent results in 32 patients (94.12%), good results in 2 (5.88%), and fair results in 0 (0%). Notably, no secondary displacement, osteonecrosis, or major complications—including nonunion, iatrogenic neurovascular injury, myositis ossificans, or chronic elbow dysfunction—were documented during postoperative surveillance. Conclusions : K-Hammer-guided medial Kirschner wire insertion offers a technically streamlined and reproducible solution for irreducible flexion-type pediatric supracondylar humeral fractures, effectively eliminating iatrogenic ulnar nerve injury while minimizing soft tissue trauma. This technique establishes adequate biomechanical stability at the fracture site and facilitates optimal long-term restoration of elbow joint kinematics.