Techniques and Methods Acetabular Morphological Analysis in Patients with High Dislocated DDH using Three-dimensional Surface Reconstruction Technique

Objective To simulate acetabular morphology and perform acetabular quantitative analysis in high dislocated developmental dysplasia of the hip (DDH) patients using three-dimensional (3D) surface reconstruction technique, in order to understand the acetabular anatomic features and develop operative strategies for acetabular reconstruction. Methods 3D pelvic images were reconstructed by Mimics software from CT data of 13 patients (13 hips) with high developmental DDH and 13 normal persons (26 hips). True acetabular superior-inferior diameter, anterior-posterior diameter, acetabular depth, medial wall thickness, abduction angle and anteversion angle were measured and compared between the two groups of participants. Results Irregular acetabular shape was found in high dislocated group, showing a triangle with wide upper and narrow lower. The acetabular quantitative analysis revealed (38.29±2.71) mm superior-inferior diameter, (21.74±5.33) mm anterior-posterior diameter, (15.50±2.93) mm acetabular depth, (6.80±2.97) mm medial wall thickness, (49.29±7.40) ° abduction angle and (23.82±11.21) ° anteversion angle in high dislocated patients. The superior-inferior diameter, anterior-posterior diameter and acetabular depth of high dislocated patients were significantly smaller than those of the normal controls (\P<0.05). However, the medial wall thickness, abduction angle and anteversion angle of high dislocated patients were significantly bigger than those of the normal controls (\P<0.05). Conclusion 3D reconstruction technique can restore true acetabular morphology and perform quantitative analysis. Compared with normal controls, high dislocated DDH patients have acetabular features: irregular shape, lower opening, higher medial wall and bigger abduction and anteversion angles. Joint arthroplasty surgery in high dislocated DDH patients needs to look at these acetabular features.