【Abstract】 Objective To explore the methods and appl ication value of surface shaded display (SSD) and multiplanarreconstruction (MPR) in the evaluation of acetabular morphology in patients with developmental dysplasia of the hip (DDH) before total hip arthroplasty (THA). Methods From October 2003 to November 2006, 17 patients (3 males and 14 females, aging from 35 years to 61 years) with osteoarthritis secondary to DDH were scanned with spiral CT preoperatively. According to the Crowe standard, 19 dysplasia hips were classified as type I in 4 hips, type II in 9 hips, type III in 6 hips. The obtained hip CT data were developed with SSD and MPR to observe spational position and bone stock of the acetabula. Results The dislocated extent was 25%-89% in these dysplasia hips according to the Crowe method and their sharp angles all exceeded 45°. Bone defect occurred to each of the acetabula, among which it was located in anterosuperior acetabulum in 5 hips, in superolateral acetabulum in 11 hips and in posterosuperior acetabulum in 3 hips. The hip images made with MPR showed that the minimum thickness of the medial wall of acetabula ranged from 2.0 mm to 10.9 mm. Among 15 unilateral dysplasia patients, the opening difference anddepth difference between the dysplasia acetabulum and the contralateral one ranged from 2.7 mm to 19.1 mm and from 2.3 mm to 13.1 mm, respectively. Conclusion SSD and MPR of spiral CT are effective methods in evaluating acetabular morphology preoperation and contribute to intraoperative acetabular reconstruction in patients with DDH performed THA.
ObjectiveTo investigate the impact of the Salter innominate osteotomy on the acetabular morphology and direction and the relationship between them in children with developmental dislocation of the hip (DDH) by three-dimensional CT. MethodsBetween January 2013 and January 2015, 51 patients with unilateral DDH were treated. All patients were females with an average age of 2 years and 5 months (range, one year and 6 months to 5 years). All the patients underwent open reduction of the hip, Salter innominate osteotomy, proximal femoral osteotomy, and hip cast immobilization for treatment. The data of three-dimensional CT before surgery and at 1 week after surgery were measured and collected as follows:the anterior acetabular index (AAI), posterior acetabular index (PAI), axial acetabular index (AxAI), acetabular anteversion angle (AAA) of the acetabulum, and the distances of the forward, outward, and lateral rotation of the distal osteotomy fragments. The differences of AAI, PAI, AxAI, AAA between before and after surgeries were compared and the difference values of the data with significant difference results were calculated. The relationship between the difference values and the distances of three different rotation directions before and after surgeries were tested by Spearman correlation analysis. ResultsThere were significant differences in the AAI, PAI, and AAA between before and after surgery (P<0.05), but no significant difference was found in the AxAI between before and after surgery (t=0.878, P=0.384). The difference values of AAI, PAI, and AAA were (4.518±4.601), (4.219±6.660), and (3.919±4.389)° respectively. The distances of the outward, lateral, and forward rotation of the distal osteotomy fragments after surgery were (0.420±0.339), (2.440±0.230), and (0.421±0.311) cm. There was a significant correlation between the three different rotation directions and AAI difference (P<0.05), especialy the outward rotation (r=0.981). There was a correlation between the outward, forward rotation and PAI, AAI differences (P<0.05), and no significant correlation between the lateral rotation and PAI, AAA was found (P>0.05). There was a significant correlation between the forward rotation and AAA difference (r=0.841). ConclusionSalter innominate osteotomy can increase the curvature of the anterior wall of the acetabulum in DDH, but reduce the curvature of the rear wall. At the same time, it can also change the direction of the acetabulum, significantly decrease the acetabular anteversion, but it can not change the depth of the acetabulum. The main factors of the curvature change after Salter innominate osteotomy of DDH is attributable to outward rotation, followed by forward rotation, and the main factor of the acetabular direction change is attributable to forward rotation.