Biomechanics is the study of the structure and function of biological systems by means of methods of mechanics.

It is particularly relevant to the field of orthopedics.

A new app called BoneStress allows users to visualize the effects of action and joint loading on bone stress for different hip stem designs.

When selecting orthopedic hip implants, surgeons take into account a range of factors such as the angle of the neck of the femur in relation to the diaphysis as well as other factors such as the age and weight of the patient to select an appropriate implant.

BoneStress allows surgeons to visualize the effect of stem length and angle on radial load in the bone.

The display shows an interactive model demonstrating the effects of impaction and joint loading on bone stresses for different hip stem designs. It describes radial load transfer between implant and bone in uncemented press-fit femoral stem implantations.

The app itself is very simple and straightforward to use. Launching the app brings the user to an interactive display which can be easily manipulated using simple touch gestures. It took a few moments to understand the output of the diagram and identify the different levels of stress and implications.


Stem design (stem and neck lengths, neck angle), impaction force, and joint loading can be varied to limit implant-bone separation while maintaining bone stresses within “normal” or “osteoporotic” limits. This will allow bone ingrowth and does reduce stresses, which can be displayed. The calculations in this model are all based on a paper which is cited and accessible through the app.


This app is clearly aimed at orthopedic surgeons who are keen to visually understand the implications of different lengths of stem and/or implant on overall loading stress. This app is probably too complicated to show patients who may find the app overly complex to understand. This app can’t be used for any form of orthopedic operative planning or adjustments for individual patients.



  • Free


  • Visually appealing and straightforward to use
  • Complex biomechanics calculations clearly displayed
  • Intuitive user interface


  • Limited explanation or theory included within app (although the linked paper is useful)
  • Not immediately clear how to interpret results


  • BoneStress will appeal to visual orthopedic surgeons who are keen to further develop their understanding of hip biomechanics and its implication on implant choice.

 iTunes Link

Rating: (1 to 5 stars): 3.5/5

  1. User Interface: 3/5
  2. Multimedia usage: 5/5
  3. Price: 5/5
  4. Real world applicability: 1/5

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 apps 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.