Comparison of Anderson-Green Growth-Remaining Graphs and White-Menelaus Predictions of Growth Remaining in the Distal Femoral and Proximal Tibial Physes.

Background: Epiphysiodesis of the distal femoral and/or proximal tibial physes is commonly performed in children and adolescents to treat lower-limb length discrepancy. It is important to determine the amount of growth remaining in the physes of these patients. Two main methods are used to make this determination: the White-Menelaus arithmetic method, which assumes a consistent amount of growth per year until skeletal maturity, and the Anderson-Green growth-remaining charts, which diagram average growth per year ± 2 standard deviations. The purpose of the present study was to evaluate these apparently disparate predictions of growth remaining in a cohort of patients managed with epiphysiodesis.

Methods: From a database of patients managed with epiphysiodesis for lower-limb length discrepancy, we identified all healthy, unoperated leg segments with follow-up to skeletal maturity. We compared the amount of observed growth with the growth predicted by the White-Menelaus method and the Anderson-Green growth-remaining graphs, for both skeletal and chronological ages.

Results: A total of 441 healthy segments (201 femora and 240 tibiae) in 221 patients (105 boys and 116 girls) with an age range of 9.0 to 16.5 years at the time of epiphysiodesis were analyzed. We observed no relationship between the length percentile of the leg segments at the time of epiphysiodesis and the amount of growth that actually occurred. Growth in the distal femoral and proximal tibial physes was relatively constant (9 and 6 mm per year of skeletal growth, respectively). Skeletal age was a better predictor of growth remaining than chronological age for both methods of estimation. Although the distribution of growth remaining in the present study resembled the Anderson-Green growth-remaining charts, that distribution was not associated with the initial length of leg segments.

Conclusions: The White-Menelaus method predicted the amount of growth remaining more accurately than the Anderson-Green growth-remaining charts. The distribution of growth remaining observed in the present study resembled that of the Anderson-Green growth-remaining graphs but was not predicted by the initial bone segment length.

Clinical Relevance: The present study found no positive association between the length percentile of leg segments and the amount of growth that occurred in an epiphysiodesis-age group. This finding can explain the comparative accuracy of the White-Menelaus method and the possible source of prediction errors in the straight-line graph and multiplier methods.