Canal Fill of the Forearm Bones When Placing Intramedullary Nails in the Pediatric and Adolescent Populations.

Background: In the lower extremity, studies have suggested an optimal nail diameter to medullary canal diameter (ND/MCD) ratio to minimize postoperative complications. The goal of this study was to determine whether a correlation exists between the occurrence of complications, angulation, and range of motion and the ratio of the ND/MCD in the upper extremity.
Methods: A total of 85 radius and ulna fractures treated with flexible intramedullary nails had ND/MCD ratios measured. Random-effects models were developed to determine the association between complications and ND/MCD ratio, angulation and ND/MCD ratio, and range of motion and ND/MCD ratio. The results were reported for unadjusted models and adjusted models.
Results: Of the 85 forearm fractures treated with intramedullary nailing, there were 3 complications. The average follow-up was 6 months. The ND/MCD ratios were categorized as <0.50, 0.50 to 0.59, and ≥0.60. There was not a significant association between the different ratios and angulation, or risk of complication. There was an association between the ND/MCD ratio ≥0.60 and decreased pronation of -1.58° (-2.77° to -0.38°) and supination of -2.68° (-4.91° to -0.46°) ( P < .05).
Conclusion: This study found that there was not an association between the nail to canal diameter ratio and postoperative angulation in forearm fractures treated with flexible intramedullary nails. When choosing a flexible nail for forearm fractures, there does not appear to be an optimal ratio; it is therefore reasonable to use the ND that passes more easily.
Competing Interests: Declaration of Conflicting InterestsThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: One of the authors consults for Axogen and Medartis; has royalties with Springer; and is on committees for Pediatric Orthopaedic Society of North America, American Academy of Pediatrics, American Association for Hand Surgery, American Academy of Orthopaedic Surgeons, and American Society for Surgery of the Hand. The remaining authors declare that they have no conflict of interest.