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Published on: February 10, 2015
Magnetic resonance imaging evaluation of acetabular orientation in normal Chinese children
YiQiang Li1, YuanZhong Liu, QingHe Zhou
1Guangzhou Women and Children's Medical Center, Guangzhou Medical University Southern Medical University, Guangzhou, China.
Insights
Acetabular orientation angles (AAA and AIA) remain stable in Chinese children up to age 16. While cartilage femoral head coverage is constant, bony coverage increases with age, indicating developmental changes in hip joint structure.
Area of Science:
- Pediatric Orthopedics
- Radiology
- Developmental Anatomy
Background:
- Acetabular orientation is crucial for hip joint stability and development.
- Limited data exists on acetabular orientation changes with age in pediatric populations using MRI.
- Understanding these changes is vital for diagnosing hip abnormalities.
Purpose of the Study:
- To investigate age-related changes in acetabular orientation and femoral head coverage in normal Chinese children.
- To establish normative data for bony and cartilage acetabular anteversion angle (AAA), acetabular inclination angle (AIA), and acetabular index (AI).
- To measure changes in total femoral head coverage angles (a-TCA and c-TCA) with age.
Main Methods:
- Retrospective analysis of 180 hip MRIs from children aged 6 months to 16 years.
- Inclusion of subjects with normal hip MRI readings.
- Measurement of bony and cartilage AAA, AIA, AI, a-TCA, and c-TCA, categorized into 14 age groups.
Main Results:
- Bony and cartilage AAA and AIA remained constant across all age groups (6 months to 16 years).
- Bony acetabular inclination angle (AIA) was significantly larger than cartilage AIA.
- Bony acetabular index (AI) decreased with age, while cartilage AI remained stable.
- Bony femoral head coverage (a-TCA and c-TCA) increased with age, whereas cartilage coverage remained unchanged.
Conclusions:
- Acetabular anteversion and inclination angles are stable in normal Chinese children from 6 months to 16 years.
- Femoral head coverage by the acetabulum increases in bony terms but not in cartilage terms with age.
- These findings provide normative reference values for pediatric hip development assessment.
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.
