We compared the accuracy of the growth remaining
method of assessing leg-length discrepancy (LLD) with the straight-line
graph method, the multiplier method and their variants. We retrospectively
reviewed the records of 44 patients treated by percutaneous epiphysiodesis
for LLD. All were followed up until maturity. We used the modified Green–Anderson
growth-remaining method (Method 1) to plan the timing of epiphysiodesis.
Then we presumed that the other four methods described below were
used pre-operatively for calculating the timing of epiphysiodesis. We
then assumed that these four methods were used pre-operatively.
Method 2 was the original Green–Anderson growth-remaining method;
Method 3, Paley’s multiplier method using bone age; Method 4, Paley’s
multiplier method using chronological age; and Method 5, Moseley’s
straight-line graph method. We compared ‘Expected LLD at maturity
with surgery’ with ‘Final LLD at maturity with surgery’ for each
method. Statistical analysis revealed that ‘Expected LLD at maturity
with surgery’ was significantly different from ‘Final LLD at maturity
with surgery’. Method 2 was the most accurate. There was a significant
correlation between ‘Expected LLD at maturity with surgery’ and
‘Final LLD at maturity with surgery’, the greatest correlation being
with Method 2. Generally all the methods generated an overcorrected
value. No method generates the precise ‘Expected LLD at maturity
with surgery’. It is essential that an analysis of the pattern of
growth is taken into account when predicting final LLD. As many
additional data as possible are required. Cite this article:
