CT Image Study of Proximal Femur in Adults DDH Patients

Abstract：Objective To investigate the morphological anatomical abnormalities of proximal femur of high developmental dysplasia of hip( DDH )in adults in Sichuan province ,and provide anatomical basis for the total hip arthroplasty( THA ).Methods 28 hips in 23 adult patients with Crowe Ⅲ ~ Ⅳ DDH were acquired through pre-operative CT images. The neck-shaft angle,anteversion angle,trans-diameter and anteroposterior diameter of femoral medullary cavity of proximal and superior segment and isthmus were measured,and calculated to get the canal flare index(CFI). The results were then compared with normal hips. Results In DDH cases,the neck-shaft angle was(117. 33 ± 3. 70)°,anteversion angle was(32. 16 ± 4. 11)°. The trans-diameter and anteroposterior diameter of femoral medullary cavity of proximal segment was(29. 28 ± 2. 03)mm and (26. 28 ± 1. 49)mm,superior segment was(12. 99 ± 1. 46)mm and(13. 88 ± 1. 03)mm,the isthmus was(9. 86 ± 0. 77)mm and(12. 68 ± 1. 87)mm. The canal flare index was(3. 56 ± 0. 68). There were significant differences in the morphological pa-rameters of femur between suffering hips and normal hips. The differences were highly statistically significant. Conclusion For THA on Adult with DDH,efforts should be make to take its anatomical morphological variation into full consideration. The fem-oral medullary cavity should be expanded in the posterior and exterior part,and select the correct femoral prosthesis to rectify anteversion angle and prevent the fracture of femur.