Elastic Stable Intramedullary Nailing in Length Stable Versus Unstable Pediatric Femoral Shaft Fractures: A Comparison of Clinical, Radiographic, and Pedobarographic Outcomes

Background: Pediatric diaphyseal femoral fracture (PDFF) is one of the most common injuries requiring hospitalization. Elastic stable intramedullary nailing (ESIN) is commonly used for PDFFs in ages 5 to 11. The optimal treatment method for length unstable PDFF is a subject of ongoing debate. This study aimed to compare clinical, radiographic, and pedobarographic outcomes of ESIN between length stable and unstable PDFF. Methods: We retrospectively reviewed patients undergoing ESIN treatment for isolated PDFF between 2016 and 2021. Exclusion criteria were (1) history of ipsilateral or contralateral lower extremity fractures, (2) highly comminuted or segmental fractures, (3) body weight >50 kg, and (4) comorbidities affecting bone quality, range of motion, or neurologic status. The patients were divided into 2 groups according to length stability. Clinical, radiographic, and pedobarographic data were then assessed to compare groups. Results: Twenty-five patients were included (17 length stable and 8 length unstable PDFF) with a mean age of 73.6±17.8 months. There was no significant difference between groups in age, side of injury, body weight, follow-up duration, and nail-canal diameter ratio. Mean deformity in the fracture site in the early postoperative x-rays was not significantly different between groups ( P =0.661). After a mean follow-up of 27.8±14.2 months (range, 12–67), there was no significant difference in mechanical axis deviation, distal femur joint orientation angle, or limb-length discrepancy in both groups. The pedobarographic assessment revealed that the length unstable group had a significantly higher external foot progression angle in the injured extremity (9.8°±6.9° vs. 1.3°±5.6°, P =0.031). However, the length stable group had no significant difference in the foot progression angle (4.9°±5° vs. 3°±4.3°, P =0.326). There was no significant difference in either group for other pedobarographic parameters. Conclusion: ESIN is a safe and effective option for length-unstable PDFF, yet attention should be paid to the rotational alignment. Although significant external rotation deformity occurs in length-unstable PDFF, it has no implications for the other pedobarographic parameters. Level of Evidence: Level IV.