Magnetic resonance imaging evaluation of acetabular orientation in normal Chinese children

Abstract

There are no data regarding the acetabular orientation on magnetic resonance imaging (MRI); this study investigates the changes of acetabular orientation with age in normal Chinese children.We retrospectively analyzed the medical records of children who underwent hip MRI examination at our hospital from January 2009 to December 2015. A total of 180 patients with normal MRI reading of the hip joints were included and were divided into 14 groups according to age: from 6 months of age and then for each year from 1 to 16 years. The bony and cartilage acetabular anteversion angle (AAA), acetabular inclination angle (AIA), and acetabular index (AI) were measured. Total bony and cartilage femoral head coverage angles were measured on axial section total femoral head coverage angle (a-TCA) and coronal section total femoral head coverage angle (c-TCA).The mean bony AAA and AIA were 12.2 ± 2.5° and 50.9 ± 2.5°, respectively; both of them stayed constant from the age of 6 months to 16 years. Similar results were found in cartilage AAA (12.1 ± 2.5°) and AIA (41.2 ± 3.0°). There was no difference between bony and cartilage AAA, but bony AIA was significantly larger than cartilage AIA. Bony AI was 24.1 ± 2.4° at the age of 6 months, decreasing to 12.5 ± 2.3° by 12 to 13 years of age; cartilage AI (5.9 ± 1.7°) maintained a steady value with age. The mean bony a-TCA and c-TCA at 6 months were 117.0 ± 5.8° and 127.5 ± 5.1°, increasing to 144.5 ± 4.6° and 140.7 ± 2.5° at the age of 16 years. However, the cartilage a-TCA (145.2 ± 7.2°) and c-TCA (154.1 ± 5.7°) did not change significantly with age.Both bony and cartilage AAA and AIA remain constant up to the age of 16 years in normal Chinese pediatric population. Although the cartilage coverage of femoral head by the acetabulum remains unchanged with age, the bony coverage of femoral head increases.

Development of acetabular anteversion in children with normal hips and those with developmental dysplasia of the hip: a cross-sectional study using magnetic resonance imaging

“…In a normal newborn, the acetabulum is a cartilage complex composed of acetabular cartilage and Y-shaped cartilage, and the development of the acetabulum is mainly characterized by endochondral ossification after birth. Li et al (2016) measured the OAA and CAA of 180 children with normal hips in different age groups from 6 months to 16 years by using MRI, and found that OAA and CAA were both relatively constant among the different age groups. They speculated that this may be due to the compressive stress of the femoral head on the acetabulum being uniform in the normal hip joint, which tends to balance the growth of the ilium, ischia, and pubis, thereby keeping the acetabulum in a stable axial opening direction.…”

The Anatomical Position of Graf’s Standard Plane and Its Relationship With Pelvic Morphology: A Computed Tomography-Based Study

“…Further, we used data from slightly older children (aged 3-5 years) to overcome this issue. There have been some reports that pelvic morphology slightly changes between zero and three years of age [ 17 - 19 ], but the morphological change is small. Weiner et al reported that the acetabular anteversion remains almost the same from zero to five years of age [ 18 ], and in the reports of Li et al, it is shown that anteversion and acetabular coverage change only about 1 degree bony from zero to five years of age [ 19 ].…”

“…There have been some reports that pelvic morphology slightly changes between zero and three years of age [ 17 - 19 ], but the morphological change is small. Weiner et al reported that the acetabular anteversion remains almost the same from zero to five years of age [ 18 ], and in the reports of Li et al, it is shown that anteversion and acetabular coverage change only about 1 degree bony from zero to five years of age [ 19 ]. Huseynovr et al estimated pelvic morphology from infant to elderly person and stated that pelvic morphology changes little until around age 10, after which it changes significantly for each sex [ 20 ].…”

Anthropometric measurements of the pediatric hip using CT-based simulated anteroposterior radiographs of the pelvis

“…Similarly, Li et al . [40] evaluated the hip morphometry of 180 healthy children of age 1–16 years and did not find any significant gender differences regarding acetabular inclination and Tönnis angle. Comparably, van der List et al .…”