Bone lengthening in children: how to predict the complications rate and complexity?

Complications arising from limb-lengthening procedures are often severe leading to long-term residuals. The aim of this study was to determine whether the complication rate and complexity could be predicted using a distraction index for bone lengthening in children.

This study retrospectively reviewed a series of 116 lower limbs lengthening in 88 consecutive patients (mean age 13.5). Mean follow-up 3.8 years. Lengthening percentage, lengthening index, distraction regenerate length, additional surgeries, and complications rate were used to evaluate the results of limb lengthening. The correlation between lengthening percentage and complication rate was particularly analyzed and its practicability illustrated. Scatter plots of complication rate (%) against lengthening percentage were constructed, and linear regression was used to investigate mathematical relationship between the variables.

The lengthening index was 33 +/- 12.1 days/cm. The length of distraction regenerate was 6 +/- 3.2 cm. The lengthening percentage was 21 +/- 16.5. The scatter plots of neurological complication rate, residual deformities rate, broken pins rate, joint contractures rate, and hypertension rate against lengthening percentage showed a positive linear relationship with r = 0.8.

The number of complications increased considerably with the increase in lengthening percentage. The lengthening percentage correlates very well with the complication rate and can be used to predict the complication rate.

During planning a lengthening procedure, the lengthening percentage should be a useful tool to predict the complications rate and to discuss the risks and benefits with patients and their families. The knowledge about predictable complications should help prevent and early detect expected complications.