For children with various growth abnormalities, limb lengthening procedures can lead to dramatic improvements in functionality and quality of life.

The Multiplier app is a great resource that contains many easy to use calculators for predicting various heights, limb lengths, and growth remaining curves.

The application is designed by the International Center for Limb Lengthening in the Rubin Institute for Advanced Orthopedics at Sinai Hospital of Baltimore – a reassuring fact when it comes to accuracy.

This app is designed for orthopedic healthcare professionals working with growth conditions.

This app automates calculations to predict mature height and bone length in children. The app delivers well on this objective. Previously, pediatric orthopedic surgeons would use large charts or graphs to plot out the growth remaining curves–tools that were not designed for effective patient communication. The Multiplier app is a quick mobile application for growth measurements that makes the calculation process more engaging and enjoyable for pediatric patients.

User Interface

The app opens with a list of common (and not so common) measurement options.


The question mark in the upper right corner gives the user helpful tips on how to use the app or how to choose the correct calculator for a given measurement.

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Once a main category is selected, there is a list of subcategories that are presented to the user. The app guides you through these categories or subcategories clicking on the options you want until you reach the calculation screen.


The calculation screen has a list of variables to enter before the app runs your calculation. The app requests common information such as sex, date of birth, age, limb length discrepancy and current height. All of these variables are easily obtainable during a single clinic visit.

additional info

The app also has an Additional Resources section from the Main Menu that explains the calculations, has growth tables, and a bibliography discussing their calculation methods. Once a calculation is complete, it also gives the practitioner the option to email the results. This is very helpful to have a copy on record. The app also allows the user to print a copy of the calculation to discuss with patients and families.


  • Free


  • The app includes programs for all major growth calculations.
  • The calculations are accurate when compared to previous graphing methods.
  • The app user interface is easy to use and engages patients well in the measurement and analysis process.


  • None

Healthcare workers that would benefit from the app

  • Any healthcare worker who has a role in pediatric or young adult growth modulation.


  • Overall, this application is easy to use, delivers well on its intended purpose, and makes the growth measurement process more engaging for patients. If you work with limb length and growth discrepancies, you should definitely check out this application.

Type of Device used to review app–iPhone 5
Version of App–3.5

iTunes Link

Rating: (1 to 5 stars): 4/5

  1. User Interface: 5/5 – The information is presented in a list format with easy data entry. With a few clicks, the calculations are complete and clearly displayed. I have seen a pediatric orthopedic surgeon at our institution let his patients input the information. The families enjoy seeing the quick calculations and children enjoy helping with the application.
  2. Multimedia usage: 1/5 – The app does not have much multimedia integration, but this is not the primary purpose of the app.
  3. Price: 5/5 – The application is free and there are no in-app purchases.
  4. Real world applicability: 4/5 – This is a great application, but its clinical utility is only useful to a small population in the medical world.

Nathan Skelley is an orthopaedic surgery resident at Washington University in St. Louis/Barnes-Jewish Hospital. He was born and raised in Joplin, Missouri where he developed his interest in mobile health technologies and orthopaedics. After attending Cornell University, where he majored in Science and Technology studies, he earned his medical degree from Johns Hopkins School of Medicine. Nathan Skelley works to integrate mobile health technologies in his treatment of orthopaedic sports injuries.

Disclaimer:: This post does not establish, nor is it intended to establish, a patient physician relationship with anyone. It does not substitute for professional advice, and does not substitute for an in-person evaluation with your health care provider. It does not provide the definitive statement on the subject addressed. Before using these apps please consult with your own physician or health care provider as to the app’s validity and accuracy as this post is not intended to affirm the validity or accuracy of the apps in question. The app(s) mentioned in this post should not be used without discussing the app first with your health care provider.