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By International Center for Limb Lengthening, Rubin Institute for Advanced Orthopedics, Sinai Hospital of Baltimore

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-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
• Achondroplasia
- Height
- Sitting Height
- Leg Length
• Fetus
- Length of tibia or femur at birth and maturity
• Foot
- Foot Length
- Foot Length Discrepancy
• Spine
- 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.

What's New in Version 5.0

In the “Height and CDC Growth Charts” section, we have added the ability to plot a child’s height and weight on the CDC growth charts. The charts contain percentile curves that use age and gender-specific information to show the distribution of body measurements in U.S. children. Under “Additional Resources,” we have added new illustrations that show how to use a radiograph of the left hand to determine the bone age (skeletal age) of a child. Unlike other methods of determining bone age that use multiple criteria, the shorthand bone age (SBA) method uses one criterion for each age (see Heyworth et al. The shorthand bone age assessment: a simpler alternative to current methods. J Pediatr Orthop. 2013;33(5):569-74.). Under “Additional Resources,” we added new images to the “Standard Measurements” section and improved the way these images are displayed. We have also optimized the app so that it is compatible with iOS 8 as well as the latest iPhones and iPads.

iPhone Screenshots

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Customer Reviews

Quick and well designed

As a pediatric orthopedist with a focus in deformity correction, I find this app to be an excellent resource. Within the limits of the data on which the program is based, I have not found a better resource. Excellent for quick teaching and calculations in the office setting.

Useful easy-to-use app

Very clinically useful app - can be easily used in the middle of a busy clinic to calculate limb length discrepancy, growth remaining, timing of epiphysiodesis and much more; very helpful resources in "Additional resources" for bone age, normal joint angles and oblique plane deformity calculations. Growth charts are great to show parents. Highly recommend.

Fantastic update!

Very useful update to an already critical App for pedipods. The new bone age section for hand x-Rays is simple to use and efficient. The new CDC growth chart option makes it easy to share graphically displayed data with parents. Thanks for these new tools!

View in iTunes
  • Free
  • Category: Medical
  • Updated:
  • Version: 5.0
  • Size: 35.5 MB
  • Language: English
  • Seller:
Rated 12+ for the following:
  • Infrequent/Mild Medical/Treatment Information

Compatibility: Requires iOS 7.0 or later. Compatible with iPhone, iPad, and iPod touch.

Customer Ratings

We have not received enough ratings to display an average for the current version of this application.
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