The Multiplier App automates calculations to predict mature height and bone length in children. This method was created originally in Baltimore at the University of Maryland, and subsequently developed at the International Center for Limb Lengthening (ICLL), Rubin Institute for Advanced Orthopedics (RIAO), Sinai Hospital of Baltimore.

We have taught the Multiplier Method for more than 10 years at our annual Baltimore Limb Deformity Course ( These calculations are typically performed by hand, using various formulas. Certain calculations are easy, but others involve more complicated formulas. Utilizing this App will reduce the time needed for these routine calculations, and decrease errors. You need only input the values about a patient (sex, age, length) and the App will execute the required Multiplier formula.

The Multiplier App will allow you to make the following calculations:
Lower Extremity
• Limb Length Discrepancy (LLD) (Congenital)
• LLD (Developmental)
• Growth Remaining
• Bone Length
• Timing of Angular Correction
• Timing of Epiphysiodesis
• Comprehensive (Congenital) Limb Length Discrepancy and Epiphysiodesis
Upper Extremity
• LLD (Congenital)
• LLD (Developmental)
• Growth Remaining
• Bone Length
Height and CDC Growth Charts
• Calculates height at maturity, calculates height at every age, and plots the patient’s height and weight on the CDC growth charts
• Height
• Sitting Height
• Leg Length
• Length of tibia or femur at birth and maturity
• Foot Length
• Foot Length Discrepancy
• Sitting Height at Maturity
Bone Age: Elbow
• Shows a radiographic scoring system to determine skeletal age
Bone Age: Hand
• Shows you how to use radiographic criteria to determine skeletal age
Oblique Plane Deformity
• Calculates magnitude, orientation, and direction of an oblique plane deformity
Inclined Osteotomy Rotation Angle
• Calculates the rotational orientation and the vertical inclination of the osteotomy

This APP also provides the following additional resources:
Figures that show the standard measurements for the lower limb and foot, the multiplier formulae that the app uses to perform the calculations, tables that show the values that are used in the multiplier formulae, figures that show the development of the apophyses, epiphyses, and bones, a bibliography, and a user guide.

Disclaimer: No growth prediction method is 100% accurate; this App is not a substitute for sound and careful clinical judgment.
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What's New

We have corrected an issue with a data entry screen.
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Additional Information

October 30, 2018
Current Version
Requires Android
4.1 and up
Content Rating
Offered By
Sinai Hospital of Baltimore, Inc.
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