Acta Orthop Belg. 2021 Sep;87(3):435-441.
The current retrospective study investigates the natural evolution of head-shaft angle (HSA) and neck-shaft angle (NSA) in childhood. It is not known if a high HSA in early childhood leads to a high HSA in adulthood. This study aims to characterize the evolution of HSA and compares it with the more commonly known NSA in healthy children. We measured radiographs of 84 different healthy hips of children between 3 and 14.5 years old who underwent at least 2 radiographs of the pelvis, corresponding to 286 measurements. We used a linear mixed model to determine the covariance between random intercept and slope while allowing each individual hip to change over time. The covariance for HSA between random intercept and random slope was -4.262 (p < 0.001), corresponding to a high negative correlation of -0.717, for NSA -2.754 (p = 0.031) or a high negative correlation of -0.779. HSA and NSA were strongly correlated, a value of 0.736 (p < 0.001) was measured. The high negative correlation for random intercept and random slope means that the higher the initial value (intercept), the steeper the decline (slope). Therefore HSA decreases faster in hips with high HSA at an early age. Hips with high HSA in early childhood do not necessarily lead to hips with high HSA in adulthood. Our results may aid in future clinical decision making in patients with developmental dysplasia of the hip (DDH) with high HSA in particular.
本回顾性研究旨在探讨儿童时期头干角（HSA）和颈干角（NSA）的自然演变。目前尚不清楚儿童早期的高 HSA 是否会导致成年后的高 HSA。本研究旨在描述 HSA 的演变，并将其与健康儿童中更为人熟知的 NSA 进行比较。我们测量了 84 名 3 至 14.5 岁不同髋关节健康儿童的 X 光片，这些儿童至少拍摄了 2 次骨盆 X 光片，共进行了 286 次测量。我们使用线性混合模型来确定随机截距和斜率之间的协方差，同时允许每个个体的髋关节随时间变化。HSA 的随机截距和随机斜率之间的协方差为-4.262（p < 0.001），对应的相关系数为-0.717，对于 NSA 为-2.754（p = 0.031）或-0.779 的高负相关。HSA 和 NSA 高度相关，相关系数为 0.736（p < 0.001）。随机截距和随机斜率的高负相关意味着初始值（截距）越高，下降（斜率）越陡峭。因此，在幼年时 HSA 较高的髋关节中，HSA 下降得更快。幼年时 HSA 较高的髋关节并不一定会导致成年时 HSA 较高。我们的研究结果可能有助于未来对髋关节发育不良（DDH）患者，特别是 HSA 较高的患者进行临床决策。
