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Success Story Brian Bartlett - Above Knee Amputee, Inventor of the BTK

Updated: Apr 4, 2023

May, 20th, 2015: Brian was recently featured in Newsweek. Read the article here.

Brian Bartlett is an above-knee amputee. After an above-the-knee amputation in 1998 following a road traffic accident, you’d perhaps expect a member of the US Ski Team to slow down a little and reconsider involvement in extreme sport. However, Brian Bartlett didn’t see it that way. Only months after surgery, he was back on the slopes (and flying through the air), skiing without a prosthesis. Brian began to discuss prosthetic options with Cornerstone that could help him when skiing and getting back to cycling, particularly standing and pedaling out of the saddle. He wasn’t prepared to accept the negative answer he had heard. At this point, no specialized kit for such activities was commercially available. And so, Brian’s quest began. More than 9 years later, his dream has become a reality for those involved in specialized sporting activities. who is using the Bartlett Tendon Knee (BTK)? Cornerstone is one of only two certified fitters of the BTK knee in the USA!


Brian is the inventor of the BTK ( Bartlett Tendon Knee ). By incorporating a unique and creative design, the BTK mimics the smooth fluid function of a natural knee. Cornerstone is one of only two certified fitters of the BTK knee in the USA!


For Brian, cycling is elite-level downhill mountain bike racing and hard road cycling. He currently competes on the mainstream downhill circuit, where he is the only adaptive rider. Not content with providing himself with a tool to compete at the highest level, he is also passionate that others benefit from the opportunity to ride without the restrictions of some more conventional designs. Early production units were fitted to some military amputees at the Walter Reed Army Medical Centre in the US, and towards the end of 2009, the Bartlett Tendon hit the shores of the UK. It’s only fair to point out that this specialized design is not plug-and-play. There is a period of relearning if the rider will optimize the function available. It is far from a free-swinging knee that is passive. During seated cycling, polyurethane tendons connected to the prosthetic socket pass over the knee and insert into a receiver on the shin. Energy stored within the tendons is returned during the downward cycle, contributing to powering the cycle compared to free-swinging knees. The design also allows the rider to stand and sprint out of the saddle, enabling Brian to power up to 30mph on his road bike on flat ground. A Rock Shox shock absorber in the design provides a forgiving platform during standing downhill riding.

"You have a greater feeling of control over your bike." - Former Royal Marine, Glyn Theobald

In October 2009, Glenn Johnstone, from County Durham, became the first person in the UK to use the design. He explains: “There is a period of learning, and it’s definitely about the person working with the knee, but it’s simply awesome! Already, after some practice, the performance is great. Now, when I push down and have the momentum on my prosthetic side, it feels like I’ve got a knee again when pedaling”. Former Royal Marine Glyn Theobald has also been using the design since December 2009, adds: “Once the initial orientation period is over you begin to see what advantages this knee gives you over normal walking prosthesis whilst cycling. You have a greater feeling of control over your bike. The ability to stand and drop back into the saddle under control and pedal out of the saddle again is not only an incredible feeling but also gives you the ability to apply extra power for short steep climbs and sprints”.

The Bartlett Tendon Knee and Cornerstone - a great partnership.

Over recent years, there has been a trend of sports-specialized prosthetic devices becoming available for many levels of amputation. The Bartlett Tendon is not for all above-the-knee amputees. Still, it is certainly an exciting contribution he developed through one man’s passion and commitment to pushing the boundaries. Here at Cornerstone, we look forward to working with Brian.

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