Abstract
BackgroundAccurate femoral neck anteversion angle (FNA) measurement is of great significance in the diagnosis and treatment of developmental dysplasia of the hip (DDH) in children. The FNA measurement still remains a controversy. We aimed to verify the accuracy of our CT method by 3D printing technology and to evaluate its clinical value.MethodsSixty-eight children with unilateral DDH were enrolled, and their FNA was measured using 2D-CT and 3D-CT, respectively, by three observers. This procedure was repeated 3 months later. The above measurement outcomes were then compared with the results in the 3D-printed femur (3D-PF) model. The FNA in the 3D-PF model was measured by three observers (two radiologists and one orthopedist; all were professors) collectively through electronic angle instrument.ResultsThe primary measurement of FNA at the affected hips by 2D-CT was 44.0 ± 6.1, 49.5 ± 8.9, and 52.8 ± 7.9°, respectively. On the 3D-CT, it was 47.6 ± 5.4, 49.3 ± 6.8, and 48.6 ± 6.2°. Three months later, the FNA on 2D-CT was 49.3 ± 10.5, 42.8 ± 7.4, and 45.1 ± 9.3°, and it was 48.0 ± 6.5, 48.9 ± 7.2, and 49.0 ± 5.7° on 3D-CT, respectively. The FNA in the 3D-PF model at the affected and unaffected hips was 48.5 ± 6.6 and 36.9 ± 13.1°. There were significant differences between 2D-CT and 3D-PF measurements, but no significant difference was found between 3D-CT and 3D-PF measurements. The results by 2D-CT showed significant differences among groups and between the groups. However, the results by 3D-CT had no significant differences among groups or between the groups.ConclusionThe results of our study showed that 3D-CT is a more precise, and reproducible method for FNA measurement in DDH. The FNA at the affected hips is 11.6° larger than the unaffected in DDH children aged 3–8 years.
Highlights
Developmental dysplasia of the hip (DDH) is commonly seen in pediatric orthopedics, and pathological characteristics of developmental dysplasia of the hip (DDH) are shallow acetabulum, enlarged femoral neck anteversion angle (FNA), and deformation of femoral head
Results of FNA in 2D-CT, 3D-CT, and 3D-printed femur (3D-PF) measurement For femurs at the dislocated sides of the 68 patients, in the first measurement, the FNA measured by the three observers were 44.0° ± 6.1°, 49.5° ± 8.9°, and 52.8° ± 7.9° on 2D-CT, respectively, and 47.6° ± 5.4°, 49.3° ± 6.8°, and 48.6° ± 6.2° on 3D-CT
Proximal femoral derotation osteotomy is often used in surgery for children with DDH to correct the large FNA, so as to achieve concentric reduction of femoral head and acetabulum [23, 24]
Summary
Developmental dysplasia of the hip (DDH) is commonly seen in pediatric orthopedics, and pathological characteristics of DDH are shallow acetabulum, enlarged FNA, and deformation of femoral head. Diagnosis and treatment are very important for the recovery of limb function. Femoral neck anteversion angle (FNA) enlargement is one of the important pathological changes of DDH [3, 4]. It is found that FNA is closely related to the hip stress and dysplasia, and is critical for the choice of surgical methods [7, 8]. How to accurately measure FNA has always been a hotspot in the orthopedic field. Accurate femoral neck anteversion angle (FNA) measurement is of great significance in the diagnosis and treatment of developmental dysplasia of the hip (DDH) in children. We aimed to verify the accuracy of our CT method by 3D printing technology and to evaluate its clinical value
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
