Li Don T, Cui Jonathan J, Henry Havalee T, Cooperman Daniel R
Departments of Orthopaedics and Rehabilitation.
Cell Biology, Yale School of Medicine, New Haven, CT.
J Pediatr Orthop. 2019 Mar;39(3):e173-e176. doi: 10.1097/BPO.0000000000001249.
Walker and Goldsmith's classic article on fetal hip joint development reported that neck/shaft angle did not change from 12 weeks of gestational age through term while version increased from 0 to 40 degrees. This suggests no change in coronal alignment during development, a conclusion we dispute. By re-examining their data, we found that the true neck/shaft angle (tNSA) decreased by 7.5 degrees as version increased by 40 degrees from 12 weeks of gestational age to term.
Four investigators measured both femoral version and neck-shaft angle from photographs published by the authors of femurs at multiple stages of maturation from 12 weeks of gestational age to term. The tNSAs and inclination angles were calculated for each femur illustrated using previously validated formula. Changes in the morphology of the femur over time were analyzed using a Student t test. Interobserver and intraobserver reliability were also determined by the Pearson R coefficient.
As reported by Walker and Goldsmith, apparent neck/shaft angle (aNSA) did not significantly change during maturation, whereas version increased by 40 degrees. However, tNSA decreased by 7.5 degrees during maturation, while the inclination increased by 32 degrees over the same period. This paper demonstrates angular changes in both the coronal and transverse planes with a 4:1 ratio of angular change in the transverse and coronal planes respectively. Interobserver Pearson coefficient R=0.98 and an intraobserver Pearson coefficient R=0.99.
Although Walker and Goldsmith reported angular changes only in the transverse plane, we conclude that they identified angular changes in both the coronal and transverse planes. Here we show it is mathematically necessary for tNSA to decrease, if aNSA remains constant as version increases.
A reader who is not well versed in the difference between aNSA and tNSA or version and inclination cannot appreciate what Walker and Goldsmith presented. Surgeons operating on the proximal femur also benefit from understanding these distinctions.
沃克和戈德史密斯关于胎儿髋关节发育的经典文章报道，从孕12周直至足月，股骨颈干角未发生变化，而股骨前倾角度从0度增加到40度。这表明在发育过程中冠状面排列没有变化，我们对这一结论提出质疑。通过重新审视他们的数据，我们发现从孕12周直至足月，随着股骨前倾角度增加40度，真实的股骨颈干角（tNSA）减小了7.5度。
四位研究人员从孕12周直至足月多个成熟阶段的股骨照片中测量了股骨前倾角度和颈干角，这些照片由股骨作者发表。使用先前验证的公式为每张所示股骨计算tNSA和倾斜角度。使用学生t检验分析股骨形态随时间的变化。观察者间和观察者内的可靠性也通过皮尔逊R系数确定。
正如沃克和戈德史密斯所报道的，在成熟过程中，表观颈干角（aNSA）没有显著变化，而股骨前倾角度增加了40度。然而，在成熟过程中tNSA减小了7.5度，而同期倾斜角度增加了32度。本文展示了冠状面和横断面的角度变化，横断面与冠状面角度变化的比例分别为4:1。观察者间皮尔逊系数R = 0.98，观察者内皮尔逊系数R = 0.99。
尽管沃克和戈德史密斯仅报道了横断面的角度变化，但我们得出结论，他们确定了冠状面和横断面的角度变化。在此我们表明，如果随着股骨前倾角度增加aNSA保持不变，从数学上来说tNSA必然减小。
不精通aNSA和tNSA之间差异或股骨前倾角度和倾斜角度差异的读者无法理解沃克和戈德史密斯所呈现的内容。进行股骨近端手术的外科医生也将从理解这些差异中受益。
