Treatment of Displaced Pediatric Supracondylar Humerus Fracture Patterns Requiring Medial Fixation: A Reliable and Safer Cross-pinning Technique

Introduction: Treatment of displaced Gartland type 3 supracondylar humerus fractures in children may include closed reduction and percutaneous pinning. The pin configuration may be all-lateral entry or cross-pin. Despite the improved stability possible with cross-pinning, there is an inherent iatrogenic risk to the ulnar nerve of about 6%. As medial fixation may be necessary for certain fracture patterns, this study was conducted to evaluate the risk of ulnar neuropathy using a technique here described and developed to minimize injury to this structure. Methods: A retrospective review was performed on all children treated for a supracondylar humerus fracture at our institution between 2003 and 2010. All the type 3 displaced fractures were placed into 2 groups: lateral-entry pinning and cross-pinning. The 2 groups were then compared for risk of ulnar nerve injury, and a post hoc power analysis was performed. Results: A total of 381 supracondylar humerus fractures met the inclusion criteria. Our cross-pinning technique was used in 187 (49%) of the children with a mean age of 5.8 years (range, 0.92 to 13.92 y). There were 4 ulnar nerve injuries in the entire cohort and 2 sustained as iatrogenic injuries in the cross-pinning group (1.1%). There was no significant difference between our 2 groups in regard to risk of ulnar nerve injury (P = 0.24). There is a statistically significant lower risk of ulnar nerve injury in our cross-pinning technique than previously described techniques (P = 0.0028), with a post hoc power analysis of 93%. Conclusions: Despite the inherent risk for iatrogenic nerve injury with cross-pinning completely displaced supracondylar humerus fractures, there is often a need to use this technique to improve fixation and stability of the fracture. Our method of cross-pinning is safe and reproducible for providing fracture stability with a significant decrease in the risk of iatrogenic ulnar nerve injury (1 in 94) when a medial pin is required. Level of Evidence: Level III-therapeutic studies.