# Primal's 3D Knee vs Bone Ninja Sensei

The clearest difference is device support: Primal's 3D Knee at 3 against Bone Ninja Sensei's 1. Bone Ninja Sensei's advantage is iOS requirement (11.4 vs 15.0). On price, update cadence, ads and in-app purchases there is nothing between them.

Both are free to download. Primal's 3D Knee sells 1 one-off in-app purchase and Bone Ninja Sensei sells 1 in-app purchase, starting at $14.99 per year. Whichever you choose, the download price is not the number that matters.

Primal's 3D Knee ships an update every 2 months, Bone Ninja Sensei every 3 months. The most recent releases landed on November 7, 2026 and November 12, 2026 respectively.

## The numbers

| Metric | Primal's 3D Knee | Bone Ninja Sensei |
| --- | --- | --- |
| Price | Free | Free |
| Rating | — | **[3.7 (3 ratings)](https://appshunter.io/ios/app/bone-ninja-sensei/id6450483301/reviews)** |
| Number of ratings | — | **3** |
| Positive reviews | — | 25.0% of reviews |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | **Every 2 months** | Every 3 months |
| Monetization | — | Free with in-app purchases |
| Size | 125 MB | 48 MB |
| Requires iOS | 15.0 | **11.4** |
| Devices | **iPhone, iPad, iPod** | iPad |
| Age rating | 12+ | 4+ |
| Developer | [Pharma Intelligence UK Ltd](https://appshunter.io/developer/1678054030) | [LifeBridge Health](https://appshunter.io/developer/460335164) |

## What reviewers say

### Primal's 3D Knee

[App page](https://appshunter.io/ios/app/primals-3d-knee/id1658547427)

**Features:** Vision Pro support

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Primal's 3D Knee | $39.99 | one-time |


### Bone Ninja Sensei

[App page](https://appshunter.io/ios/app/bone-ninja-sensei/id6450483301)

This educational tool, created by orthopedic surgeons, helps medical professionals learn to analyze long bone deformities. It provides tools for drawing, measuring, and simulating osteotomy solutions on provided or uploaded radiographs.

**Highlights:** Analyze long bone deformities, Radiograph analysis tools, Simulate osteotomy solutions, Upload custom radiographs, Drawing and measuring tools, Educational case examples

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Annual Subscription Plan | $14.99 | per year |


## Frequently asked questions

### Is Primal's 3D Knee free?

Primal's 3D Knee is free to download, with in-app purchases available.

### Is Bone Ninja Sensei free?

Bone Ninja Sensei is free to download, with in-app purchases available.

### Do Primal's 3D Knee or Bone Ninja Sensei have ads?

Neither Primal's 3D Knee nor Bone Ninja Sensei shows ads.

### Which is updated more often, Primal's 3D Knee or Bone Ninja Sensei?

Primal's 3D Knee ships an update every 2 months, and Bone Ninja Sensei every 3 months. Most recently, Primal's 3D Knee was updated on November 7, 2026 and Bone Ninja Sensei on November 12, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*