We are pleased to announce that the Limber UniLeg has passed rigorous testing to ensure compliance with ISO 10328:2016 standards. These standards are essential for verifying the safety and durability of lower-limb prostheses.
This blog is intended to summarize the results of our recent ultimate, proof, and cyclic load testing at P6 load-levels, which cover patients that weigh up to 275 pounds.
Test Overview
As a medical device manufacturer, we build devices to very specific standards, with measured and monitored parameters. The devices that we submitted for testing are what we refer to as “worst-case” UniLegs. This is essentially a product that in real life, would never be more likely to fail in any aspect relevant to these tests. A worst-case UniLeg design was used for testing so that we could ensure any device built within the UniLeg design envelope will be covered by these testing results.
Our two “worst case” UniLegs were subjected to static proof, ultimate strength, and cyclic fatigue tests under two primary conditions: heel loading and forefoot loading.
All tests were performed utilizing an electrodynamic testing machine with a slightly modified test fixture setup following the ISO 10328:2016 standard. The modified fixture was identified as necessary to accommodate the unique, one-piece design of the UniLeg prosthetic device that incorporates the socket.
Results
We are very pleased to share that the Limber UniLeg met all requirements for proof, ultimate, and cyclic load testing for P6 load-levels as specified in the ISO 10328:2016 standard. Both of our “worst-case” UniLegs were able to withstand 3 million cycles of heel loading and 3 million cycles of forefoot loading.
This type of cyclic testing demonstrates the durability of the UniLeg for long-term use, which is incredibly important for a patient who plans to walk on this device for many years to come.
Both of the tested devices withstood ultimate load testing over 1,000 pounds of force. (1,098 lbf to be exact). The ultimate test demonstrates the safety of the UniLeg even if exposed to a single extreme event. We can think about this as the highest calculated load possible, during use, where the UniLeg survived with minimal permanent deformation, no cracks, and without catastrophic failure.
Both UniLegs passed proof loading over 500 pounds of force with less than 5 mm of permanent deformation. The proof testing demonstrates the structural integrity of the UniLeg when exposed to occasional severe events, while remaining fully functional.
Summary
Passing the rigorous testing outlined in the ISO 10328:2016 standard proves the UniLeg’s strength and durability, making it a safe and reliable choice for amputees and their prosthetists. If you would like to learn more about the UniLeg and Limber’s revolutionary new manufacturing processes, reach out to us at info@limberprosthetics.com.
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Special thanks to Paul Martinez, Materials Engineer for running the tests, collecting data and summarizing results.
Special thanks to Joshua Pelz, PhD for reviewing test setup, protocol and results.