Lower Limb Prosthesis Cyclic Testing

At the Orthopaedic Trauma Institute at San Francisco General Hospital, I worked on a wide range of novel orthopaedic technologies, with a focus on mechanical design, fabrication and testing. For each of these testing setups, I built them entirely from scratch using primarily milling machine and other machine shop tools. Mechanical tests are performed on medical devices, sometimes in cadaveric specimens, in the MTS Bionix 858 (a servohydraulic testing system) along with an Optotrack Tracking System to track movement of test subjects in 3D space.  
For this particular test, we were performing cyclic testing on a novel 3D printed lower prosthesis. Running the leg through this test will ensure that it can be worn by a real human being and has the lifetime as tested in the machine. Following previous studies, both follow ISO Standard 10328 (Structural testing of lower limb prostheses).
Picture
Current TA, Kogler GF and Barth DG. Static structural testing of trans-tibial composite sockets. Prosthetics and Orthotics International, 1999. 23. 113-122.
Picture
Lee WCC, Zhang M. Fatigue test of low-cost flexible-shank monolimb trans-tibial prosthesis. Prosthetics and Orthotics International. Dec 20016; 30(3): 305-315.
ROLE
Research Associate

CONTRIBUTIONS
  • Designed ISO standard 10328 cyclic test for a novel lower limb prosthesis
  • Machined test fixtures in-house
​
SKILLS
Biomechanical testing
Verification and validation testing

TOOLS
Milling machine
MTS Bionix 858 
Optotracking System

Design Concepts

Let's Get to Machining!

Full Assembly
Acorn Nut
​Applies a downward force onto the construct 
20 Degree Wedge
​Simulates natural gait cycle during testing 
3D Printed Lower Limb Prosthesis
Should be able to withstand full cyclic loading without breaking