Abstract:

BACKGROUND: Although, the previous studies on acetabular morphological characteristics have yielded some results, quantitative description of the acetabular surface morphology has not yet been unified because of the special nature of acetabular structure and location, and this is bound to affect the accuracy of the diagnosis and treatment of hip disease.
OBJECTIVE: To investigate the CT measuring methods to acetabulum geometric parameters.
METHODS: Seventy cases performed CT scan were selected, including 50 normal adults (a total of 100 hips on both sides) and 20 cases with unilateral congenital hip dislocation. The hip CT images of the subjects were treated with coronal reconstruction and three-dimensional reconstruction, in order to compare the coronal and three-dimensional measurement value of acetabulum upper chamber, and to compare acetabulum upper camber between the normal side and the abnormal side in the congenital hip dislocation group. The acetabulum posterior abduction angle, anterior acetabulum index and posterior acetabular index were measured in the images in accordance with scan bed and the body coronal plane.
RESULTS AND CONCLUSION: The acetabulum upper camber measured in coronal plane and three-dimensional image was (39.99±6.1)° and (40.13±5.80)° respectively, and there was no significant difference (P > 0.05). The acetabulum upper camber measured value of the unilateral congenital hip dislocation patients in normal side and abnormal side on coronal plane was (48.95±3.80)° and (63.56±6.35)°, and there were significant differences (P < 0.01). There were significant differences in acetabulum posterior abduction angle, anterior acetabulum index and posterior acetabular index measured in both sides on the images in accordance with scan bed and the body coronal plane (P < 0.01), and there were no significant differences in accordance with coronal plane (P > 0.05). The measurement is more reliable on the images in accordance with the body coronal plane when measuring acetabulum posterior abduction angle, anterior acetabulum index and posterior acetabular index. It can reflect the acetabular real condition and provide quantitative indicators for the diagnosis and treatment of hip disease.

Key words: bone and joint implants, photographs and images of bone and joint, acetabulum, geometric parameter, hip joint, three-dimensional reconstruction, camber angle, abduction angle, acetabulum index