606 Acta Orthopaedica 2011; 82 (5): 606–609 Iatrogenic ulnar nerve injury after pin fixation and after ante- grade nailing of supracondylar humeral fractures in children Robert Eberl, Christian Eder, Elisabeth Smolle, Annelie M Georg Singer Weinberg, Michael E Hoellwarth, and Department of Pediatric and Adolescent Surgery, Medical University of Graz, Graz, Austria Correspondence: robert.eberl@medunigraz.at Submitted 11-02-24 Accepted 11-07-11 Background and purpose Ulnar nerve injury may occur after pinning of supracondylar fractures in children. We describe the outcome and compare the rates of iatrogenic injuries to the ulnar nerve in a consecutive series of displaced supracondylar humeral fractures in children treated with either crossed pinning or ante- grade nailing. Methods Medical charts of all children sustaining this fracture treated at our department between 1994 and 2009 were retrospec- tively reviewed regarding the mode of treatment, demographic data including age and sex, the time until implant removal, the outcome, and the rate of ulnar nerve injuries. Results 503 children (55% boys) with an average age of 6.5 years sustained a type-II, type-III, or type-IV supracondylar fracture. Of those, 440 children were included in the study. Ante- grade nailing was performed in 264 (60%) of the children, and the others were treated with crossed pins. Iatrogenic ulnar nerve injury occurred in 0.4% of the children treated with antegrade nailing and in 15% of the children treated with crossed pinning. After median 3 (1.6–12) years of follow-up, the clinical outcome was good and similar between the 2 groups. Interpretation Intramedullary antegrade nailing of displaced supracondylar humeral fractures can be considered an adequate and safe alternative to the widely performed crossed K-wire fixa- tion. The risk of iatrogenic nerve injury after antegrade nailing is small compared to that after crossed pinning.  In children, supracondylar fractures are the most common type of fracture of the elbow region (Omid et al. 2008). Boys usually have a higher incidence of this type of fracture but some recent reports in the literature describe rising rates in girls (Cheng et al. 2001). Most of the patients are 5–7 years old (Davis et al. 2000, Omid et al. 2008, Zamzam and Bakar- man 2009). At this age, the potential for fracture remodel- ing decreases; therefore, malreduction may lead to persistent deformity (Wessel et al. 2003). In displaced fractures, the most common operative treat- ment is closed reduction and pin fixation. Different techniques have been reported, but crossed pinning with postoperative immobilization is the preferred technique (Brauer et al. 2007, Kocher et al. 2007, Zamzam and Bakarman 2009). Iatrogenic injury to the ulnar nerve has been described in up to 20% of the cases treated with crossed pinning (Lyons et al. 1998). In addition, radial pinning may damage the radial and anterior interosseous nerve (Brauer et al. 2007, Kocher et al. 2007, Omid et al. 2008). In 1990, a technique with antegrade nailing for supracondy- lar fractures was first described by Prevot et al. (1990). Schaf- fer et al. (2007) and Weinberg et al. (2003) treated 60 and 50 children with this technique and reported no iatrogenic inju- ries to the ulnar nerve. We determined the outcome and compared the rates of iat- rogenic injuries to the ulnar nerve in a consecutive series of displaced supracondylar humeral fractures in children treated with either crossed pinning or antegrade nailing. Patients and methods We retrospectively analyzed the medical charts of all children who had sustained a supracondylar humeral fracture and who were treated at our department between 1994 and 2009. This included age and sex, type of fracture and treatment, the time until implant removal, the outcome, and the rate of ulnar nerve injuries. Fractures were classified according to the Gartland system as modified by Leitch et al. (Gartland 1959, Leitch et al. 2006). Type-I fractures are undisplaced or minimally dis- placed (< 2 mm). Type-II fractures are characterized by fracture displacement of more than 2 mm and intact poste- rior cortex. Type-III injuries are displaced fractures without cortical contact, and type-IV injuries are multidirectionally unstable fractures. Open Access - This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the source is credited. DOI 10.3109/17453674.2011.623574