Leg-length discrepancy and associated risk factors after paediatric femur shaft fracture: a multicentre study

Abstract

Purpose: This study was performed to investigate leg-length discrepancy (LLD) and associated risk factors after paediatric femur shaft fractures. Methods: A total of 72 consecutive patients under 13 years old (mean age 6.7 years; 48 boys, 24 girls) with unilateral femur shaft fracture, and a minimum follow-up of 18 months, were included. The amount of LLD was calculated by subtracting the length of the uninjured from that of the injured limb. Risk factors for an LLD >= 1 cm and >= 2 cm were analyzed using multivariable logistic regression analysis. Results: Hip spica casting, titanium elastic nailing and plating were performed on 22, 40 and ten patients, respectively. The mean LLD was 7.8 mm (sd 8.8) and 29 (40.3%) had a LLD of >= 1 cm, while nine (12.5%) had a LLD of >= 2 cm. There were significant differences in fracture stability (p = 0.005) and treatment methods (p = 0.011) between patients with LLD < 1 cm and >= 1 cm. There were significant differences in fracture site shortening (p < 0.001) and LLD (p < 0.001) between patients with length-stable and length-unstable fractures. Fracture stability was the only factor associated with LLD >= 1 cm (odds ratio of 4.0; p = 0.020) in the multivariable analysis. Conclusion: This study demonstrated that fracture stability was significantly associated with LLD after paediatric femur shaft fractures. Therefore, the surgeon should consider the possibility of LLD after length-stable femur shaft fracture in children.