Multiplier

Predict Height & Bone Length

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 19 years at our annual Baltimore Limb Deformity Course (www.DeformityCourse.com). These calculations are typically performed by hand, using various formulae. Certain calculations are easy, but others involve more complicated formulae. Utilizing this app will reduce the time needed for these routine calculations and decrease errors. You need only input certain data (sex, age, length) and the app will calculate the answer by using the appropriate 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) LLD and Epiphysiodesis
- Scanogram Calculations (calculates femur/tibia lengths, overall limb length discrepancy, and amount/side of femur/tibia discrepancies)

• 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 (calculates the length of tibia or femur at birth and maturity)

• Foot
- Foot Length
- Foot Length Discrepancy

• Spine (calculates sitting height at maturity)

• Oblique Plane Deformity (calculates magnitude, orientation, and direction of an oblique plane deformity)

• Inclined Osteotomy (calculates the rotational orientation and the vertical inclination of the osteotomy)

This app also provides the following additional resources:
-Bone Age: Elbow and Hand (shows how to determine skeletal age by using radiographs of the elbow or hand)
-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 multipli