BACKGROUND We investigated the normal development of the secondary ossification centers of the acetabulum, focusing on their location and the amount of acetabular coverage increased by them. METHODS We enrolled 132 patients who were 7 to 16 years of age and had no pelvic deformity but did have ≥1 os ischium, os ilium, and/or os pubis on abdominal or pelvic computed tomographic (CT) scans. The locations of the ossification centers were evaluated by adopting an orientation using 0° for the superior acetabulum, 90° for the anterior acetabulum, 180° for the inferior acetabulum, and 270° for the posterior acetabulum, on a reconstructed 3-dimensional (3D) CT image. The acetabular coverage increase by the os ischium, os ilium, or os pubis was defined as the difference in the posterior acetabular sector angle (ΔPASA), posterosuperior acetabular sector angle (ΔPSASA), superior acetabular sector angle (ΔSASA), anterosuperior acetabular sector angle (ΔASASA), or anterior acetabular sector angle (ΔAASA) measured with and without each secondary ossification center. Patients were grouped into 3 age ranges: late childhood, preadolescence, and early adolescence. The location of each ossification center and the increase in acetabular coverage were compared between these groups. RESULTS In the late-childhood group, the median start-to-end positions in right hips were 269° to 316° for the os ischium, 345° to 356° for the os ilium, and 81° to 99° for the os pubis. These positions tended to be wider in the early-adolescence group at 252° to 328° for the os ischium (p < 0.001), 338° to 39° for the os ilium (p = 0.005), and 73° to 107° for the os pubis (p = 0.049) in right hips. In right hips in the late-childhood group, the median values were 8.1° for ΔPASA, 14.0° for ΔPSASA, 9.9° for ΔSASA, 11.1° for ΔASASA, and 3.9° for ΔAASA; and in the early-adolescence group, the median values in right hips were 10.7° for ΔPASA, 12.9° for ΔPSASA, 8.4° for ΔSASA, 7.4° for ΔASASA, and 5.6° for ΔAASA. Only the median ΔPASA was larger in the early-adolescence group than in the late-childhood group (p = 0.026). Similar results were observed in left hips. CONCLUSIONS In early adolescence, the secondary ossification centers appeared at more extended areas along the acetabular rim, and the increase in acetabular coverage by the secondary ossification centers tended to be larger in the posterior area but not in the anterior or superior area. LEVEL OF EVIDENCE Diagnostic Level III . See Instructions for Authors for a complete description of levels of evidence.

中文翻译：

---

髋臼次生骨化中心的典型发展及其对股骨头髋臼覆盖的影响。


背景 我们调查了髋臼次级骨化中心的正常发育，重点关注它们的位置和它们增加的髋臼覆盖量。方法 我们招募了 132 例患者，年龄在 7 至 16 岁之间，没有盆腔畸形，但在腹部或盆腔计算机断层扫描 （CT） 扫描中有 ≥1 个坐骨、髂骨和/或耻骨。在重建的 3 维 （3D） CT 图像上，采用 0° 为髋臼上部、90° 为髋臼前部、180° 为髋臼下部和 270° 为后髋臼，从而评估骨化中心的位置。坐骨、髂骨或耻骨口增加的髋臼覆盖度定义为髋臼后扇角 （ΔPASA）、髋臼后上扇角 （ΔPSASA）、髋臼上扇角 （ΔSASA）、髋臼前上扇角 （ΔASASA） 或髋臼前扇角 （ΔAASA） 的差异，在有和没有每个次级骨化中心的情况下测量。患者分为 3 个年龄范围： 儿童晚期、青春期前和青春期早期。比较了这些组之间每个骨化中心的位置和髋臼覆盖率的增加。结果 在儿童晚期组中，右髋关节的中位起点到终点位置为坐骨 269° 至 316°，髂骨口 345° 至 356°，耻骨口 81° 至 99°。这些位置在青春期早期组中趋于更宽，坐骨为 252° 至 328° （p < 0.001），髂骨为 338° 至 39° （p = 0.005），右髋关节耻骨为 73° 至 107° （p = 0.049）。在儿童晚期组的右髋部，ΔPASA 的中位值为 8.1°，ΔPSASA 为 14.0°，9。ΔSASA 为 9°，ΔASASA 为 11.1°，ΔAASA 为 3.9°;在青春期早期组中，右髋部的中位值为 ΔPASA 为 10.7°，ΔPSASA 为 12.9°，ΔSASA 为 8.4°，ΔASASA 为 7.4°，ΔAASA 为 5.6°。只有青春期早期组的中位 ΔPASA 大于儿童晚期组 （p = 0.026）。在左髋关节中观察到类似的结果。结论 在青春期早期，继发性骨化中心出现在沿髋臼缘的更延伸区域，次发性骨化中枢对髋臼覆盖度的增加在后部趋于较大，而在前部或上部区域则不然。证据级别 诊断 III 级。有关证据级别的完整描述，请参阅作者说明。