Multiplier vs DRU Classification
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Multiplier
This app automates complex calculations for predicting mature height, bone length, and limb length discrepancies in children. It simplifies manual methods, reducing calculation time and errors for various orthopedic and growth-related assessments.
- Predict mature height
- Calculate bone length
- Assess limb length discrepancy
- Analyze growth remaining
- Plot height on CDC charts
- Scanogram calculations
- Foot length analysis
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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 19 years at our annual Baltimore Limb Deformity Course (http://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 · Foot Height · Foot Height 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 multiplier values that are used in the formulae · Figures that show the Solomin Foot Analysis (Deformity correction planning for the midfoot, hindfoot, and ankle using reference lines and angles provided by Dr. Leonid Solomin) · Figures that show the development of the apophyses, epiphyses, and bones · Bibliography · User guide DISCLAIMER: No growth prediction method is 100% accurate; this App is not a substitute for sound and careful clinical judgment. PRIVACY POLICY: We respect the privacy of the people who use the International Center for Limb Lengthening apps. The Multiplier app does not collect, use, or distribute any data from the users.
DRU Classification
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The distal radius and ulna (DRU) classification is an accurate parameter of a child’s maturity status. It is useful for management of spine and limb deformities as it can predict the peak growth spurt and growth cessation with good sensitivity and specificity. It has also been shown to be an indicator of scoliosis curve progression and predict which curves will deteriorate. This app provides users with a tool to understand the DRU classification, how to use the classification for grading skeletal maturity, and also for guiding treatment. In addition, this app has a calculation function for final body height prediction for female patients with idiopathic scoliosis. Current features: 1. Explanation of the DRU classification 2. Distal radius and ulna features on x-rays for grading 3. DRU grading quiz 4. Final height prediction calculator 5. Useful publications in this field of paediatric skeletal growth and scoliosis curve progression Features to come: 1. Curve progression prediction 2. Image capture and automated grading and prediction
Screenshots
Verdict
The clearest difference is update cadence: Multiplier at every 7 months against DRU Classification's every 29 months. On price, ads, in-app purchases and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
Multiplier ships an update every 7 months, DRU Classification every 29 months. The most recent releases landed on July 2, 2026 and September 13, 2026 respectively.
| Parameter | Multiplier | DRU Classification |
|---|---|---|
| Price | Free | Free |
| Rating | 4.6 (24 ratings) — better | — |
| Positive reviews | 83.3% of reviews | — |
| Number of ratings | 24 — better | — |
| Update frequency | Every 7 months — better | Every 29 months |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | — |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 13.0 | 12.0 — better |
| Further details — not scored | ||
| Size | 62 MB | 28 MB |
| Age rating | 12+ | 17+ |
| Developer | LifeBridge Health | Department of Orthopaedics and Traumatology, The University of Hong Kong |
In-app purchases
Multiplier
No in-app purchases
DRU Classification
No in-app purchases
Questions
Is Multiplier free?
Is DRU Classification free?
Do Multiplier or DRU Classification have ads?
Which is updated more often, Multiplier or DRU Classification?
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