Having a thumb that is not a standard length can create problems for an individual. Whether this is because of an amputation, or it is a congenital difference, you may be looking for a prosthetic device to extend your thumb or possibly protect it. After an amputation, the residual digit can become quite sensitive, and while you may be able to function without length, easing the pain may be a good reason to try wearing a prosthesis. Another reason to consider a prosthesis is that, with time, your residual thumb, other fingers, and hand in general, may experience overuse issues that can cause long-term injuries.

Unlike the rest of the fingers, the thumb consists of two bones, or phalanges, and then the metacarpal bone. The thumb joint closest to the end of the thumb is the IP or interphalangeal joint. Next, moving closer to the palm is the MP or metacarpophalangeal joint, sometimes called the MCP. The CMC, or carpometacarpal joint is at the base of the thumb closest to the wrist. For this article, we’re going to focus on that visually missing idea, meaning options for people with amputations around the IP joint or at or near the MCP joint. For information regarding amputations “below” that point, or more proximal to the palm, please see our article Thumb Loss.

Hand

For people who’ve lost that top thumb joint but still have the rest of their thumb, one of the prosthetic options available is a Naked Prosthetics’ Thumb Driver, seen below. This is a body-powered device which extends the length of the digit and allows for better grip. There is a conductive tip option for anyone out there who uses their thumb for their phone screen. Additionally, the metal structure of the prosthesis covers the residual thumb and protects people with a sensitive thumb end.

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NP-Fishing-Tackle-900x600

Partial Hand Solutions, LLC, has an option called the Thumb Cage, pictured below. This can be customized to the correct length for the individual. It allows the CMC joint, the one inside your hand, to move the rest of the thumb. It’s secured by a silicone band and wrist strap.

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Our Arm Dynamics centers also create thumb protectors that can not only provide a shield for the residual thumb, but can give length to the wearer, allowing them to partake in more activities. There are different levels of thumb protectors based on the users’ residual anatomy and what they plan on doing with their device on a daily basis. Our patient Robert had an amputation that led to hypersensitivity in the residual part of his thumb, and the shortness of the digit made playing the guitar unpleasant, as the pick kept slipping when he played. The solution was a thumb extender/protector, which you can see him use in this video:

Our patient Matt needed something that would protect his thumb, but he didn’t want to lose the sensation pressure that his thumb provided. Andy, the prosthetist in our Minneapolis center, and his technician, Brianne, created the device below. Andy: “The finger pad was made with rolled silicone and textured to provide a tacky grasp surface as well as the ability to depress slightly (which then provided slight pressure into his residual limb for tactile sensation).”

Heavy Duty Thumb Post

Another option for anyone looking for a little more stability:

Silicone thumb socket in blue

Thumb protectors can also be cute!

Walia Thumb PX

Point Designs is a company that creates passive positional prosthetic devices. Two options are the Point Digit Partial Thumb and the Point Thumb. You can watch our patient Daniel use his Partial Thumb below:

The Point Thumb is an option for amputations near or at the MCP joint.

Point Thumb
Juan Olguin PDD Px

Point Designs goes farther, and has a device called the Point Pivot+, allowing for more range of motion for the thumb. You can learn more about that and other thumb prostheses in our Thumb Loss article.

Prosthetic options for digits have come a long way from even just ten years ago. We can’t wait to see where they progress next. Our prosthetists are up to date on all the latest available technology out there. But it’s not just about the devices. In addition to customizing the sockets and frames we create to fit our patients with comfortable, functional prostheses, we also have in-house occupational therapists who customize the therapy they offer their patients, meaning everyone walks out of our centers knowing how to use their device.

Are you or someone you know, looking to be fit with a prosthesis for their partial thumb difference? Please contact us. If you would like to leave a comment, please do so below.

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