An improved spreadsheet for calculating limb length discrepancy and epiphysiodesis timing using the multiplier method

Abstract

PurposeThe multiplier method is a technique to predict limb length discrepancy (LLD) at maturity in pediatric patients. Various tools have been developed for performing the multiplier calculations to predict LLD and timing of epiphysiodesis. These include multiplier/growth applications (apps) and a spreadsheet which have helped to facilitate LLC calculations in an efficient and easy manner. We have updated the spreadsheet to improve features for making LLD calculations and facilitate pasting data into electronic medical records (EMRs).MethodsTools currently in use were critically examined for features that limited their function, created possible sources of error or could be more user-friendly. These features were modified and recreated in an improved Excel spreadsheet that uses patient age, sex, limb lengths, and previous lengthening surgeries as inputs to predict LLD at maturity and offer options for timing of epiphysiodesis for both congenital and developmental LLD. Our multiplier spreadsheet function was then compared to manual calculations and other multiplier tools for accuracy and ease of use.ResultsOur spreadsheet accurately calculates LLD at maturity and timing of epiphysiodesis when compared to other methods. It contains a function to calculate predicted leg lengths after previous lengthenings, and concise single-page worksheets for developmental LLD, congenital LLD, and height prediction.ConclusionsThis spreadsheet was developed to provide a more efficient and user-friendly method of calculating LLD at maturity and timing of epiphysiodesis. It can easily be pasted into the EMR for ease of documentation. We recommend this method for both clinical practice and educational use.Electronic supplementary materialThe online version of this article (doi:10.1007/s11832-016-0754-4) contains supplementary material, which is available to authorized users.

The More the Merrier: Integrating Multiple Models of Skeletal Maturity Improves the Accuracy of Growth Prediction

“…Paley and colleagues the multiplier method, which predicts the limb length discrepancy at skeletal maturity with respect to a given sex and chronologic age. 20,21 Although this method is user-friendly and accessible on numerous smart phone apps and websites, 1 remaining limitation is its assumption that skeletal growth follows a Type I Shapiro proportionate growth pattern, in which the ratio of growth in the short limb to that of the long limb does not change over time. 20,22 Regardless, this system suggests that patient chronologic age may prove useful, but is not necessary, in refining estimates of skeletal growth remaining.…”

“…Although much emphasis is placed on skeletal bone age, other models have used chronologic age to predict skeletal growth. Paley and colleagues proposed the multiplier method, which predicts the limb length discrepancy at skeletal maturity with respect to a given sex and chronologic age 20,21. Although this method is user-friendly and accessible on numerous smart phone apps and websites, 1 remaining limitation is its assumption that skeletal growth follows a Type I Shapiro proportionate growth pattern, in which the ratio of growth in the short limb to that of the long limb does not change over time 20,22.…”

Prospective study of epigenetic alterations responsible for isolated hemihyperplasia/hemihypoplasia and their association with leg length discrepancy

“…However, we found no meaningful tissue-specific variant in any sample and thus discontinued the examination. Second, the predicted LLD calculated by the multiplier method may differ from the true LLD [ 34 ], although this is one of the most frequently used methods for predicting LLD [ 35 ]. Because the development of LLD over time can vary between patients with and without epigenetic alterations [ 29 ], patient-specific methods to predict LLD at skeletal maturity based on epigenotypes might be applied.…”

Applicability of Shoulder, Olecranon, and Wrist-based Skeletal Maturity Estimation Systems to the Modern Pediatric Population

“…Within pediatric endocrinology, bone age estimates serve as a tool to diagnose and manage various endocrine conditions. Other conditions in pediatric orthopaedics, like slipped capital femoral epiphysis, early-onset scoliosis, and limb length discrepancy, rely on bone age estimates for surgical planning 1–7 . Two classic skeletal maturity systems are the Greulich and Pyle (GP) skeletal atlas and the Tanner-Whitehouse staging systems, both of which require left-hand/wrist radiographs 8,9 .…”

“…Other conditions in pediatric orthopaedics, like slipped capital femoral epiphysis, early-onset scoliosis, and limb length discrepancy, rely on bone age estimates for surgical planning. [1][2][3][4][5][6][7] Two classic skeletal maturity systems are the Greulich and Pyle (GP) skeletal atlas and the Tanner-Whitehouse staging systems, both of which require left-hand/wrist radiographs. 8,9 While these systems are well-known and remain widely used, they are timeintensive, complex, and have demonstrated significant inter-observer and intra-observer variability.…”