Kelly Paula M, Diméglio Alain
Department of Paediatric Orthopaedic Surgery, CHU Lapeyronie, Montpellier, France.
J Child Orthop. 2008 Dec;2(6):407-15. doi: 10.1007/s11832-008-0119-8. Epub 2008 Aug 29.
The purpose of this review is to clarify the different methods of predictions for growth of the lower limb and to propose a simplified method to calculate the final limb deficit and the correct timing of epiphysiodesis.
Lower-limb growth is characterized by four different periods: antenatal growth (exponential); birth to 5 years (rapid growth); 5 years to puberty (stable growth); and puberty, which is the final growth spurt characterized by a rapid acceleration phase lasting 1 year followed by a more gradual deceleration phase lasting 1.5 years. The younger the child, the less precise is the prediction. Repeating measurements can increase the accuracy of predictions and those calculated at the beginning of puberty are the most accurate. The challenge is to reduce the margin of uncertainty. Confrontation of the different parameters-bone age, Tanner signs, annual growth velocity of the standing height, sub-ischial length and sitting height-is the most accurate method. Charts and diagrams are only models and templates. There are many mathematical equations in the literature; we must be able to step back from these rigid calculations because they are a false guarantee. The dynamic of growth needs a flexible approach. There are, however, some rules of thumb that may be helpful for different clinical scenarios.
For congenital malformations, at birth the limb length discrepancy must be multiplied by 5 to give the final limb length discrepancy. Multiple by 3 at 1 year of age; by 2 at 3 years in girls and 4 years in boys; by 1.5 at 7 years in girls and boys, by 1.2 at 9 years in girls and 11 years in boys and by 1.1 at the onset of puberty (11 years bone age for girls and 13 years bone age for boys).
For the timing of epiphysiodesis, several simple principles must be observed to reduce the margin of error; strict and repeated measurements, rigorous analysis of the data obtained, perfect evaluation of bone age with elbow plus hand radiographs and confirmation with Tanner signs. The decision should always be taken at the beginning of puberty. A simple rule is that, at the beginning of puberty, there is an average of 5 cm growth remaining at the knee. There are four common different scenarios: (1) A 5-cm discrepancy-epiphysiodesis of both femur and tibia at the beginning of puberty (11 years bone age girls and 13 years in boys). (2) A 4-cm discrepancy-epiphysiodesis of femur and tibia 6 months after the onset of puberty (11 years 6 months bone age girls, 13 years 6 months bone age boys, tri-radiate cartilage open). (3) A 3-cm discrepancy-epiphysiodesis of femur only at the start of puberty, (skeletal age of 11 years in girls and 13 years in boys). (4) A 2-cm discrepancy-epiphysiodesis of femur only, 1 year after the start of puberty (12 years bone age girls and 14 years in boys).
本综述的目的是阐明预测下肢生长的不同方法，并提出一种简化方法来计算最终肢体短缩以及骨骺阻滞的正确时机。
下肢生长具有四个不同阶段：产前生长（指数增长）；出生至5岁（快速生长）；5岁至青春期（稳定生长）；以及青春期，这是最后的生长高峰期，其特征是快速加速阶段持续1年，随后是持续1.5年的较为缓慢的减速阶段。孩子越小，预测就越不准确。重复测量可提高预测的准确性，而在青春期开始时计算的预测最为准确。挑战在于减少不确定性范围。对比不同参数——骨龄、坦纳征、站立身高年生长速度、坐骨下长度和坐高——是最准确的方法。图表只是模型和模板。文献中有许多数学方程；我们必须能够从这些严格的计算中抽身，因为它们并不能提供可靠保证。生长动态需要灵活的方法。然而，有一些经验法则可能对不同临床情况有所帮助。
对于先天性畸形，出生时肢体长度差异必须乘以5以得出最终肢体长度差异。1岁时乘以3；女孩3岁、男孩4岁时乘以2；女孩7岁、男孩7岁时乘以1.5；女孩9岁、男孩11岁时乘以1.2；青春期开始时（女孩骨龄11岁、男孩骨龄13岁）乘以1.1。
对于骨骺阻滞的时机，必须遵循几个简单原则以减少误差范围；进行严格且重复的测量、对获得的数据进行严谨分析、通过肘部加手部X线片完美评估骨龄并结合坦纳征进行确认。决策应始终在青春期开始时做出。一个简单的规则是，在青春期开始时，膝关节平均还有5厘米的生长空间。有四种常见的不同情况：（1）相差5厘米——青春期开始时（女孩骨龄11岁、男孩骨龄13岁）对股骨和胫骨均进行骨骺阻滞。（2）相差4厘米——青春期开始6个月后（女孩骨龄11岁6个月、男孩骨龄13岁6个月，三辐射软骨开放）对股骨和胫骨进行骨骺阻滞。（3）相差3厘米——青春期开始时（女孩骨龄11岁、男孩骨龄13岁）仅对股骨进行骨骺阻滞。（4）相差2厘米——青春期开始1年后（女孩骨龄12岁、男孩骨龄14岁）仅对股骨进行骨骺阻滞。
