Three-dimensional computed tomography analysis and anteversion study after periacetabular osteotomy of pelvis in children

Abstract

Purpose Three-dimensional computed tomography (CT) is the method of choice in understanding the morphological changes after periacetabular osteotomy in children. We studied different parameters and compared aspects of operated hip (OH) with non-operated hip (NOH) to define the maneuver that promotes normalization of the hip during repositioning of the acetabulum. Methods A total of 22 patients with 25 OHs underwent CT control scans an average of 4 years after surgery. The patients, with a mean age of 6.8 years, had either Legg-Calvé-Perthes disease (12 cases) or dysplasia (10 cases).The measurements included the anterior and posterior coverage angles of the hip and version of the acetabulum on axial CT views. The 3D reconstructed images measured the inclination of the antero– and postero–lateral lips, the external rotation and the anterior inclination of the acetabulum. Results The mean anterior coverage angle was 27° for OHs, 31° for NOHs, and 12° versus 10.3° for the posterior coverage angle. Acetabular anteversion was 2° for OHs (6.3° in the dysplastic OHs) and 6° for NOHs. The mean angle of inclination of the antero–lateral lip was 37° for OHs, 47° for NOHs, and the postero–lateral lip inclination was 56° for OHs and 67° for NOHs. Inferior 3D views showed a mean internal acetabular rotation of 1.5° (4.8° in the dysplastic OH), 3° for NOH. The anterior acetabular inclination angle measured with lateral 3D views was 6° for OHs, 11° for NOHs. Conclusion Our analysis demonstrated a mean anteversion of the acetabulum despite normalization of the anterior coverage of the hip, particularly in the dysplastic group, in which the osteotomized fragments had anteversion superior to NOH. The unexpected external rotation used to improve anterior coverage of a coax magna in Legg-Calvé-Perthes disease was responsible for the retroversion and the decrease of the posterior coverage.

Periacetabular triple osteotomy by single anterior approach for children under 6-years-old with severe acetabular deficiency: prevention of retroversion and anterior impingement

“…After freeing the acetabular fragment, its reorientation should be in two directions with the femoral head as a center of rotation: first, in the frontal plane, an important lateral rotation is performed while paying attention to avoid any external rotation (movement in the coronal plane). Second, in the sagittal plane, a slight anterior rotation (extension) is performed with an appropriate angle to correct the anterior deficiency [18,27]. We laid emphasis on lateral rotation to restore the physiological coverage of the hip as it will correct the severe lateral deficiency.…”

“…The lateral 3D-CT view (Fig. 3c, d) measures the angle of anterior acetabular inclination, which is formed by a line from the ischial spine to the antero-lateral edge of the acetabulum and the horizontal reference, which is perpendicular to a line joining the anterior superior iliac spine to the pubic symphysis [27].…”

Total Acetabular Retroversion following Pelvic Osteotomy: Presentation, Management, and Outcome

“…Also the prevalence for the Drehmann's sign (20) was increased which usually indicates a more severe form of anterior FAI (40). In literature acetabular retroversion has been reported following PAO (3, 41, 42), Salter (16, 43), Triple type (16, 44), and curved periacetabular osteotomies (13, 45). However, to the best of the authors' knowledge no reports exist on total acetabular retroversion following pelvic osteotomies.…”

“…Total acetabular retroversion was described in hips with proximal focal femoral deficiency (PFFD) only (17). Partial acetabular retroversion after PAO was associated with neurogenic disorders (42) or Legg-Calvé-Perthes disease (LCPD) (41). Xie et al (45) found decreased flexion in hips with acetabular retroversion after curved periacetabular osteotomy.…”

Relationships of hip joint volume ratios with degrees of joint laxity and degenerative disease from youth to maturity in a canine population predisposed to hip joint osteoarthritis

“…6,7,28–33 The sensitivity of 3-D CT to detect and characterize minor hip joint abnormalities is superior to that of 2-D radiography. 10,26 Also, CT is an important imaging modality for assessment of hip joint structures in children with minor symptoms of hip dysplasia, 34 classification of human dysplastic hip joints, 20 surgical planning, 15–17,19,26,34 and postoperative assessment. 10,35 Two-dimensional measures on 3-D canine hip CT images reported by others 6 differ from the measures developed in the present study because our measures included volume quantification on 3-D images.…”