Measurements of acetabular morphology in healthy children using multiplanar computed tomography reconstructions

Abstract

Hip joint morphology varies by sex and age. Computed tomography (CT) provides excellent evaluation of acetabular morphology; however, a description of the normal range of CT measurements in healthy children is lacking. This study aimed to describe the acetabular morphology on CT in healthy children by sex and at specific ages. Children who underwent pelvic CT from February 2016 to 2022 were retrospectively studied. The anterior pelvic plane was the basis for measuring lateral center-edge angle (LCEA), acetabular angle, anterior center-edge angle (ACEA), acetabular version (AcetV), anterior acetabular sector angle (AASA), and posterior acetabular sector angle (PASA). This study included 55 females and 55 males. The mean age was 12.5 years (range: 1-18 years). Patients were grouped by age: 2-7 years ( n = 50 hips), 8-11 years ( n = 50 hips), and 12-18 years ( n = 120 hips). Mean AcetV was 16.5° (range: 5.8-29.5°), mean AASA was 58.38° (range: 40.0-69.4°), mean PASA was 90.6° (range: 68.8-111.00°), mean LCEA was 27.9° (range: 19.0-40.4°), mean acetabular angle was 45.1° (range: 33.6-55.9°), and mean ACEA was 47.6° (range: 23.0-64.4°). The AcetV, AASA, PASA, LCEA, and ACEA increased with age, while the acetabular angle decreased ( P < 0.001). AcetV and PASA were highest in females ( P < 0.001). Hip joint development varies by sex across specific ages. The measurements reported provide descriptive reference data that may be used as an assessment tool for early identification of pediatric hip deformities and aid surgical planning.

Keywords: acetabular angle; acetabular sector angle; anterior pelvic plane; center-edge angle; computerized tomography; hip morphology; triradiate cartilage.