Department of Orthopaedic Surgery, Nagoya University Graduate School of Medicine, 65 Tsurumai, Showa ku, Nagoya, Aichi 466 8550, Japan.
Bone Joint J. 2014 Sep;96-B(9):1269-73. doi: 10.1302/0301-620X.96B9.33840.
Two types of fracture, early and late, have been reported following limb lengthening in patients with achondroplasia (ACH) and hypochondroplasia (HCH). We reviewed 25 patients with these conditions who underwent 72 segmental limb lengthening procedures involving the femur and/or tibia, between 2003 and 2011. Gender, age at surgery, lengthened segment, body mass index, the shape of the callus, the amount and percentage of lengthening and the healing index were evaluated to determine predictive factors for the occurrence of early (within three weeks after removal of the fixation pins) and late fracture (> three weeks after removal of the pins). The Mann‑Whitney U test and Pearson's chi-squared test for univariate analysis and stepwise regression model for multivariate analysis were used to identify the predictive factor for each fracture. Only one patient (two tibiae) was excluded from the analysis due to excessively slow formation of the regenerate, which required supplementary measures. A total of 24 patients with 70 limbs were included in the study. There were 11 early fractures in eight patients. The shape of the callus (lateral or central callus) was the only statistical variable related to the occurrence of early fracture in univariate and multivariate analyses. Late fracture was observed in six limbs and the mean time between removal of the fixation pins and fracture was 18.3 weeks (3.3 to 38.4). Lengthening of the tibia, larger healing index, and lateral or central callus were related to the occurrence of a late fracture in univariate analysis. A multivariate analysis demonstrated that the shape of the callus was the strongest predictor for late fracture (odds ratio: 19.3, 95% confidence interval: 2.91 to 128). Lateral or central callus had a significantly larger risk of fracture than fusiform, cylindrical, or concave callus. Radiological monitoring of the shape of the callus during distraction is important to prevent early and late fracture of lengthened limbs in patients with ACH or HCH. In patients with thin callus formation, some measures to stimulate bone formation should be considered as early as possible.
两种类型的骨折，即早期和晚期骨折，在软骨发育不全（ACH）和软骨发育不全（HCH）患者的肢体延长后均有报道。我们回顾了 2003 年至 2011 年间 25 例接受股骨和/或胫骨 72 个节段性肢体延长术的患者，这些患者均患有这些疾病。性别、手术时的年龄、延长的节段、体重指数、骨痂的形状、延长的量和百分比以及愈合指数均进行了评估，以确定早期（固定针取出后 3 周内）和晚期骨折（固定针取出后 3 周以上）发生的预测因素。采用 Mann-Whitney U 检验和 Pearson χ 2 检验进行单因素分析，逐步回归模型进行多因素分析，以确定每种骨折的预测因素。由于再生缓慢，需要补充措施，只有 1 名患者（2 例胫骨）被排除在分析之外。共有 24 例患者 70 个肢体纳入研究。8 例患者共发生 11 例早期骨折。在单因素和多因素分析中，骨痂的形状（外侧或中央骨痂）是与早期骨折发生相关的唯一统计学变量。6 例发生晚期骨折，固定针取出与骨折之间的平均时间为 18.3 周（3.3 至 38.4）。胫骨延长、较大的愈合指数以及外侧或中央骨痂与单因素分析中晚期骨折的发生有关。多因素分析显示，骨痂的形状是预测晚期骨折的最强因素（优势比：19.3，95%置信区间：2.91 至 128）。外侧或中央骨痂比梭形、圆柱形或凹形骨痂发生骨折的风险明显更大。在 ACH 或 HCH 患者的肢体延长过程中，对骨痂形状进行放射学监测对于预防早期和晚期骨折非常重要。对于骨痂形成较薄的患者，应尽早考虑一些刺激骨形成的措施。
