Comparison

AO Surgery Reference vs DRU Classification

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

AO Surgery Reference

Access a comprehensive online repository of surgical knowledge for fracture management. It provides detailed guidance on diagnosis, treatment, and aftercare for numerous fracture types, supported by extensive illustrations and expert review.

Highlights
  • 353 fracture types covered
  • 172 surgical approaches
  • 1222 surgical procedures
  • Over 30,000 illustrations
  • Feline, canine, and equine fracture care
  • Powerful search function
Features
Read full description

QUICK ONLINE REFERENCE IN CLINICAL LIFE Gain easy access to the award-winning AO Surgery Reference. AO Surgery Reference is an online repository for surgical knowledge. It describes the complete surgical management process from diagnosis to aftercare for all fractures of a given anatomical region, and also assembles relevant material that the AO has published before. It gives access to:   • aid in surgical decision making for 353 fracture types • 172 approaches • 1222 surgical procedures • all richly illustrated with more than 30'000 Illustrations and much more. To ensure the quality of the content, it is authored, edited, and peer reviewed by experienced AO Faculty from all over the world, some of which are also well-known textbook authors/editors. This is a relaunch of the AO Surgery Reference app utilizing the same responsive user interface that was released February 2020. The highlights are: • Consistent navigational logic and user experience on all screen sizes • Inclusion of feline, canine, and equine fracture care • Combination of Preparation – Approach – Reduction and Fixation – Aftercare into one step called treatment. • Introduction of a powerful search function, allowing simplifications of the user interface as it replaces previous shortcuts.

About

DRU Classification

Features
Read full description

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

AO Surgery Reference4 screens
DRU Classification4 screens

Verdict

The call

The clearest difference is update cadence: AO Surgery Reference at every 6 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

CostPrice · In-app purchases · Ads · Monetization

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

UpkeepUpdate frequency

AO Surgery Reference ships an update every 6 months, DRU Classification every 29 months. The most recent releases landed on September 24, 2026 and September 13, 2026 respectively.

Scorecard1 real difference · 9 level
AO Surgery Reference versus DRU Classification: the parameters behind the verdict, then further details
ParameterAO Surgery ReferenceDRU Classification
PriceFreeFree
Rating4.4 (14 ratings) — better—
Positive reviews85.8% of reviews—
Number of ratings14 — better—
Update frequencyEvery 6 months — betterEvery 29 months
AdsNoNo
In-app purchasesNoNo
MonetizationFree—
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS13.012.0 — better
Further details — not scored
Size1 MB28 MB
Age rating17+17+
DeveloperAO FoundationDepartment of Orthopaedics and Traumatology, The University of Hong Kong

In-app purchases

None

AO Surgery Reference

No in-app purchases

None

DRU Classification

No in-app purchases

Questions

Is AO Surgery Reference free?
AO Surgery Reference is free to download, with no in-app purchases.
Is DRU Classification free?
DRU Classification is free to download, with no in-app purchases.
Do AO Surgery Reference or DRU Classification have ads?
Neither AO Surgery Reference nor DRU Classification shows ads.
Which is updated more often, AO Surgery Reference or DRU Classification?
AO Surgery Reference ships an update every 6 months, and DRU Classification every 29 months. Most recently, AO Surgery Reference was updated on September 24, 2026 and DRU Classification on September 13, 2026.

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