What is a Hybrid Upper Limb Prosthesis?
by Amber Henson, on Jul 18, 2023
A hybrid prosthesis could be any device where two or three different types of prostheses are combined in one device. Prostheses are categorized as passive, body-powered, electric, activity-specific or hybrid. That might mean a device for someone with an above elbow limb difference who wants a myoelectric hand but a body-powered elbow. Or it could be someone with a partial hand limb difference — say they have no residual fingers but they do have some of their thumb. That person might want to use passive digits for their fingers, but a body-powered thumb. The picture below gives you an idea of what this looks like.
A hybrid device usually allows an increased area of function. This makes it more useful than relying on just one type of device.
Our patient, Sharif, pictured at the top of this article, has a hybrid device. Sharif has an above elbow amputation and uses a body-powered elbow (controlled by a cable you can see in the picture) and a myoelectric hand. The electrodes that activate his electric hand are part of the frame that attaches to his residual limb. His elbow is controlled by how he positions his shoulder — either up or down. He doesn’t need to lock it with his sound hand because he can simply keep his shoulder positioned in a way that keeps his elbow up at an angle.
Our patient Claudia has an interesting hybrid device. Claudia had an accident at work that resulted in an above elbow amputation. Her terminal devices include an ETD, a TASKA hand and several activity-specific devices. When she is wearing the myoelectric ETD or TASKA, she has an electric wrist rotator. But her elbow is a hybrid device in and of itself — it’s electronic, and it can be locked into place by means of a switch that Claudia manipulates with her sound hand.
Hybrid devices are also an option for people with a partial hand limb difference. Our patient Shane was out in the woods when he had an accident that resulted in the partial amputation of his pinky and ring fingers. “Originally, I was convinced that I needed a Naked Prosthetic device for my ring finger. And I thought for sure, I don’t want anything else, that’s my only option. And my Arm Dynamics prosthetist discussed the pros and cons with me, and I actually went a completely different route.” Shane learned that there were other options out there, and it turned out that a Point Designs digit was better for him. So he’s wearing a Point Designs device, which is passive, on his residual ring finger, and a Naked Prosthetics device, which is body-powered, on his residual pinky finger. Passive devices like Point Designs’ prosthetic fingers mean that Shane manipulates the grip of the finger with his sound hand or by pressing it on his leg or a nearby surface. You can see Shane’s device and hear him discuss his choice in the video below:
Our clinical teams are quite creative and always working to put together a prosthesis that will work best for their patients. This hybrid hand prosthesis is wrist driven, which is pretty rare. It combines both passive and body-powered devices. The index and middle fingers are Point Design Digits, and the Point Thumb can move laterally using the Point Pivot+ mounting system. The prosthesis essentially “harnesses” the power of the wrist movement to move the digits for grasp and release. Wrist extension pulls the fingers away from the thumb and wrist flexion brings the fingers and thumb together for grasp and pinch.
Because there are so many considerations when it comes to choosing a prosthesis (such as the patient’s goals, job type, insurance coverage, amputation level) it’s nice to know that hybrid prostheses exist for situations where more than one type of device would be ideal. Our clinical teams of prosthetists, clinical therapy specialists, technicians and assistants, work together to create the most useful device for each patient’s unique situation.
If you or someone you know would like to learn more about how they could be fit with a hybrid prosthesis, please contact us. If you have ever worn a hybrid device and would like to describe your experience, please leave a comment below. We hope you have found this article helpful.