Paediatric supracondylar humeral fractures: a technique for safe medial pin passage with zero incidence of iatrogenic ulnar nerve injury.

Introduction: The cross Kirschner wire (K-wire) configuration in closed reduction and percutaneous pinning of paediatric supracondylar humeral fracture affords superior stability. However, medial pin placement presents a risk of iatrogenic ulnar nerve injury. This study describes, in step-by-step detail, another safe method of percutaneous medial pin insertion.

Methods: The technique involved placing the patient's arm in external rotation, with elbow flexed no more than 45° after closed reduction. The surgeon held the K-wire close to its sharp end to pass it percutaneously onto the medial epicondyle, then adjusted his grip toward the blunt end. After fluoroscopy check, the wire driver was engaged and an anteriorly directed force was applied to the distal humerus fragment using the thumb of the surgeon's free hand. The K-wire was inserted at a 45° angle to the longitudinal axis of the humerus shaft. Clinical notes and radiographs of patients who underwent surgery with this technique from 2006 to 2008 were reviewed.

Results: A total of 125 patients (84 boys, 41 girls) were included, with a mean age of 7.1 (range 2-14) years. Most injuries were left-sided (72.8%, n = 91, vs. right: 27.2%, n = 34). 72 (57.6%) patients had two-pin cross K-wire configuration, while 53 (42.4%) patients had an additional lateral pin inserted. No patient had postoperative ulnar neuropathy. There were no complications of non-union, malunion or infection.

Conclusion: This safe method of medial pin placement for surgical stabilisation of paediatric supracondylar humeral fractures is easily learnt and reproducible, and produces excellent results.