University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA.
J Bone Joint Surg Am. 2011 Jun 1;93(11):1051-6. doi: 10.2106/JBJS.J.00384.
Treating patients with congenital or acquired limb-length inequality requires accurate estimations of limb length at skeletal maturity. There is controversy over the best indicator of maturity to be used for limb-length calculations. Paley popularized the multiplier method, in which chronological age is used, which has the virtue of simplicity but does not account for the wide variance in timing of the adolescent growth spurt. The purpose of this study was to determine whether the use of chronological age or the level of skeletal maturity provides more accurate limb-length predictions.
We identified patients with limb-length inequality, for whom scanograms had been obtained before and at maturity, and who had had no surgical procedures on their normal lower limb. Skeletal maturity was determined with use of the Greulich and Pyle atlas, Tanner-Whitehouse-3 method, and simplified stages described by Sanders et al. The length of the lower extremity was compared with the ultimate limb length and the actual multiplier (final limb length divided by current limb length) for each point in time. A linear model was used to determine the log-transformed multipliers for the level of skeletal maturity, and Paley's multipliers were used for chronological age. Residual standard errors were determined to compare the results of the methods. We also conducted piecewise linear regression on each of the methods and used the residual standard errors to rank their performance and cross-validated the results.
We identified twenty-four patients (twelve girls and twelve boys) who met the study criteria. Most subjects had had multiple scanograms along with skeletal age radiographs (average, 4.5) at different ages. When all ages are considered, the Paley method had the best overall performance, with residual standard errors that were typically =5 cm. However, the Paley method did not perform best for subjects at stage-2 skeletal maturity or above; in those cases, skeletal-maturity-based predictions had residual standard errors of <2 cm.
While the Paley method, which is based on chronological age, provides reasonable estimates of ultimate limb length for most patients, use of skeletal-maturity determinations appears to provide better predictions of mature limb length during adolescence.
治疗先天性或后天性肢体不等长的患者需要准确估计骨骼成熟时的肢体长度。目前，对于用于肢体长度计算的最佳成熟指标存在争议。Paley 推广了乘法器方法，该方法使用的是实际年龄，其优点是简单，但没有考虑到青春期生长突增的时间差异很大。本研究的目的是确定使用实际年龄还是骨骼成熟度能更准确地预测肢体长度。
我们确定了患有肢体不等长的患者，这些患者在成熟前和成熟时都获得了扫描图，并且他们的正常下肢没有接受过任何手术。骨骼成熟度使用 Greulich 和 Pyle 图谱、Tanner-Whitehouse-3 方法和 Sanders 等人描述的简化阶段来确定。比较了下肢的长度与最终肢体长度和每个时间点的实际乘数（最终肢体长度除以当前肢体长度）。使用线性模型确定骨骼成熟度水平的对数转换乘数，并使用 Paley 乘数进行实际年龄计算。确定残差标准误差以比较这些方法的结果。我们还对每种方法进行分段线性回归，并使用残差标准误差对其性能进行排名，并对结果进行交叉验证。
我们确定了符合研究标准的 24 名患者（12 名女孩和 12 名男孩）。大多数受试者在不同年龄时都有多次扫描图和骨骼年龄 X 光片（平均 4.5 次）。当考虑所有年龄时，Paley 方法的整体表现最佳，残差标准误差通常为 5cm。然而，对于骨骼成熟度为 2 期及以上的患者，Paley 方法的表现并不最佳；在这些情况下，基于骨骼成熟度的预测的残差标准误差小于 2cm。
虽然基于实际年龄的 Paley 方法可以为大多数患者提供合理的最终肢体长度估计，但使用骨骼成熟度测定似乎可以更好地预测青春期成熟后的肢体长度。
