Clinical validation of the multiplier method for predicting limb length at maturity, part I.

To validate the accuracy of the multiplier method in predicting bone and limb maturity lengths, radiographs of 60 patients treated for lower limb length discrepancy were measured. Longitudinal limb length data were used to predict maturity lengths of non-epiphysiodesed normal bones and short bones. Mean errors for predictions were 1.1 cm (SD = 0.9) and 1.5 cm (SD = 1.3) for the multiplier method using chronologic age and skeletal age, respectively. Regression correlation values between multiplier method predictions and actual measurements were 0.93 using chronologic age and 0.90 using skeletal age. The multiplier method was more accurate than prediction using the Anderson et al growth charts. Mean error for limb length predictions was 2.5 cm for the multiplier method using chronologic age and 2.6 cm for the Moseley method. Although as accurate as the Moseley method, the multiplier method seems to be quicker and simpler to use and requires only one data point for predicting limb length at maturity.