Department of Pediatric Orthopedics, Shengjing Hospital of China Medical University, Shenyang, Liaoning Province, China.
Acta Orthop. 2021 Jun;92(3):341-346. doi: 10.1080/17453674.2020.1866928. Epub 2021 Jan 8.
Background and purpose - Acetabular anteversion (AA) is related to hip function. Most previous studies were based on radiographic investigations that determine osseous acetabular anteversion (OAA). But children's acetabulum is mostly composed of cartilage; the cartilaginous acetabular anteversion (CAA) represents the real anteversion of the acetabulum. We measured OAA and CAA in children of various ages using MRI, and compared the developmental patterns between children with normal hips and those with developmental dysplasia of the hip (DDH).Patients and methods - The OAA and CAA were measured on MRI cross-sections of the hips in 293 children with normal hips (average age 8 years), and in 196 children with DDH (average age 34 months). Developmental patterns of OAA and CAA in children with normal hips were determined through age-based cross-sectional analysis. Differences in OAA and CAA between children with normal hips and those with DDH were compared.Results - Normal OAA increased from mean 8.7° (SD 3.2) to 12° (3.0) during the first 2 years of life and remained unchanged until 9 years of age. From 9 to 16 years, the OAA showed a minimal increase of 2°-3°. The normal CAA increased rapidly from a mean of 12° (3.1) to 15° (2.7) within the first 2 years of life, and remained constant at 15° (SD 3.4) until 16 years of age. The age-matched average OAA in the normal and DDH cases was 11° (3.2) and 15° (3.0), respectively (p < 0.001). The age-matched average CAA in normal and DDH cases was 17° (4.2) and 23° (4.5), respectively (p < 0.001). Similarly, there was a significant difference in OAA and CAA between the uninvolved hips in unilateral DDH and normal cases (p < 0.001).Interpretation - The CAA was fully formed at birth in normal children, and remained unchanged until adulthood, whereas the OAA increased with age. The OAA and CAA were both over-anteverted in DDH children. MRI evaluation is of importance in children during skeletal development when planning hip surgery.
背景与目的-髋臼前倾角（AA）与髋关节功能有关。大多数先前的研究都是基于放射学研究，这些研究确定了骨性髋臼前倾角（OAA）。但是，儿童的髋臼主要由软骨组成；软骨髋臼前倾角（CAA）代表髋臼的真实前倾角。我们使用 MRI 测量了不同年龄儿童的 OAA 和 CAA，并比较了正常髋关节儿童和发育性髋关节发育不良（DDH）儿童之间的发育模式。
患者和方法-在 293 名正常髋关节儿童（平均年龄 8 岁）和 196 名 DDH 儿童（平均年龄 34 个月）的髋关节 MRI 横断面图像上测量了 OAA 和 CAA。通过基于年龄的横断面分析确定了正常髋关节儿童 OAA 和 CAA 的发育模式。比较了正常髋关节儿童和 DDH 儿童之间的 OAA 和 CAA 差异。
结果-正常 OAA 在生命的头 2 年从平均 8.7°（SD 3.2）增加到 12°（3.0），直到 9 岁时保持不变。从 9 岁到 16 岁，OAA 仅增加了 2°-3°。正常 CAA 在生命的头 2 年内迅速从平均 12°（3.1）增加到 15°（2.7），直到 16 岁时保持在 15°（SD 3.4）不变。正常和 DDH 病例的年龄匹配平均 OAA 分别为 11°（3.2）和 15°（3.0）（p<0.001）。正常和 DDH 病例的年龄匹配平均 CAA 分别为 17°（4.2）和 23°（4.5）（p<0.001）。同样，单侧 DDH 和正常病例中未受累髋关节的 OAA 和 CAA 也存在显著差异（p<0.001）。
解释-正常儿童的 CAA 在出生时即已完全形成，直到成年后保持不变，而 OAA 随年龄增长而增加。DDH 儿童的 OAA 和 CAA 均过度前倾。在骨骼发育期间，当计划髋关节手术时，MRI 评估对儿童非常重要。
