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Validation of the multiplier method for leg-length predictions on a large European cohort and an assessment of the effect of physiological age on predictions

View Article: PubMed Central - PubMed

ABSTRACT

Purpose: The Avon Longitudinal Study of Parents and Children (ALSPAC) prospective cohort was used to determine the accuracy of the Paley multiplier method for predicting leg length. Using menarche as a proxy, physiological age was then used to increase the accuracy of the multiplier.

Methods: Chronological age was corrected in female patients over the age of eight years with documented date of first menses. Final sub-ischial leg length and predicted final leg length were predicted for all data points.

Results: Good correlation was demonstrated between the Paley and ALSPAC data. The average error in prediction depended on the time of assessment, tending to improve as the child got older. It varied from 2.2 cm at the age of seven years to 1.8 cm at the age of 14 years. When chronological age was corrected, the accuracy of multiplier increased. Age correction of 50% improved multiplier predictions by up to 28%.

Conclusion: There appears to have been no significant change in growth trajectories of the two populations who were chronologically separated by 40 years. While the Paley data were based on extracting trends from averaged data, the ALSPAC dataset provides descriptive statistics from which it is possible to compare populations and assess the accuracy of the multiplier method. The data suggest that the accuracy improves as the patient gets close to the average skeletal maturity but that results need to be interpreted in conjunction with a radiological assessment of the growth plates. The magnitude of the errors in prediction suggest that when using the multiplier, the clinician must remain vigilant and prepared to perform a contralateral epiphyseodisis if the prediction proves to be wrong. The data suggest a relationship between the multiplier and menarche. There appears to be a factorisation and when accounting for physiological age, one needs to correct by 50% of the difference between chronological and physiological age.

No MeSH data available.


Comparison of multipliers derived from Aguilar and Paley8 and the ALSPAC cohort. Line of best ft provided by the Loess method.
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Figure 2: Comparison of multipliers derived from Aguilar and Paley8 and the ALSPAC cohort. Line of best ft provided by the Loess method.

Mentions: LLMs were calculated for 10 323 readings with multipliers of greater than 1 (pre-skeletal maturity). The readings were then compared with the historical dataset, described by Paley, and are shown in Figure 2.14


Validation of the multiplier method for leg-length predictions on a large European cohort and an assessment of the effect of physiological age on predictions
Comparison of multipliers derived from Aguilar and Paley8 and the ALSPAC cohort. Line of best ft provided by the Loess method.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5382340&req=5

Figure 2: Comparison of multipliers derived from Aguilar and Paley8 and the ALSPAC cohort. Line of best ft provided by the Loess method.
Mentions: LLMs were calculated for 10 323 readings with multipliers of greater than 1 (pre-skeletal maturity). The readings were then compared with the historical dataset, described by Paley, and are shown in Figure 2.14

View Article: PubMed Central - PubMed

ABSTRACT

Purpose: The Avon Longitudinal Study of Parents and Children (ALSPAC) prospective cohort was used to determine the accuracy of the Paley multiplier method for predicting leg length. Using menarche as a proxy, physiological age was then used to increase the accuracy of the multiplier.

Methods: Chronological age was corrected in female patients over the age of eight years with documented date of first menses. Final sub-ischial leg length and predicted final leg length were predicted for all data points.

Results: Good correlation was demonstrated between the Paley and ALSPAC data. The average error in prediction depended on the time of assessment, tending to improve as the child got older. It varied from 2.2 cm at the age of seven years to 1.8 cm at the age of 14 years. When chronological age was corrected, the accuracy of multiplier increased. Age correction of 50% improved multiplier predictions by up to 28%.

Conclusion: There appears to have been no significant change in growth trajectories of the two populations who were chronologically separated by 40 years. While the Paley data were based on extracting trends from averaged data, the ALSPAC dataset provides descriptive statistics from which it is possible to compare populations and assess the accuracy of the multiplier method. The data suggest that the accuracy improves as the patient gets close to the average skeletal maturity but that results need to be interpreted in conjunction with a radiological assessment of the growth plates. The magnitude of the errors in prediction suggest that when using the multiplier, the clinician must remain vigilant and prepared to perform a contralateral epiphyseodisis if the prediction proves to be wrong. The data suggest a relationship between the multiplier and menarche. There appears to be a factorisation and when accounting for physiological age, one needs to correct by 50% of the difference between chronological and physiological age.

No MeSH data available.