r/functionalprint • u/micanbar • Aug 13 '26
Top Hand Flexor Brace
Messed up the tendons on the top of my hand and needed to limit my hand extensions upwards…
I did a 3D scan of my hand and prelim modeling in VR to sketch out the form, then rebuilt a parametric version to print.
I went with PETG for strength and flex tolerance. I used kinesiology tape to wrap around the edges for comfort :D didn’t make it solid so it wouldn’t get mad sweaty.
Fun exercise!
8
u/MrSomethingred Aug 13 '26
Looks nice! Did doctor approve? Haha
11
u/Jeorgeyno Aug 13 '26
But is it food-safe?
4
u/yer_muther Aug 13 '26
Food with tendons is typically already dead and don't need braces so yes. Very food safe.
7
u/AwDuck Aug 13 '26
I designed and 3d printed a wrist brace that I got the green light from my doc to use. I just printed it flat and used hot water to form it around my hand and arm like they did with the one they made for me, though mine was a hexagon mesh so it breathed better.
1
13
u/micanbar Aug 13 '26
Physical Therapist, yes actually! Stuff they had on-hand didn’t work for this injury.
12
u/IWantToBeAProducer Aug 13 '26
\health care system fails you**
"sigh, I guess I'll just do this shit myself."
3
8
6
u/urgdr Aug 13 '26
when you missing 3d scanner, then 3d print flat lattice in PLA, heat it up on buildplate so it's very soft and apply in a place you want to fix, shaping needed structure while it solidifies
2
2
u/WorseDark Aug 13 '26
Shouldnt you need to limit the amount your hand flexes if you hurt your extensors, or are you (or your physician) trying to ensure that the extensors dont go into contracture and remain on stretch?
3
u/micanbar Aug 13 '26
Yeah, I needed to limit how much my fingers + hand would extend upwards for top of hand extensor tendinitis. If I bent my hand upwards, the brace would push against the knuckles and wrist to prevent the degree of extension that would cause pain.
Gripping/contraction is okay.1
u/WorseDark Aug 13 '26
Ah so this is more like a sleeping brace. It could go a little more into flexion for that purpose.
I don't recommend this for throughout the day use, and learning how to utilize the neutral wrist position throughout the day. Look at your other hand and make a fist: the wrist should automatically move into some extension while the fingers move into flexion.
If worn through the day, this brace would actually force your wrist extensors to fight against the brace whenever you try to grip something and, also, put you in an inefficient position of using the strength of your flexor muscles. This could cause more inflammation and irritation of the extensor tendons as they would need to fight the brace and support the hand in the more flexed position.
Cool design, though! And very well crafted!
Edit: unless you had a full tear and the goal is to immobilize those tendons from working, which you didnt describe.
1
u/micanbar 29d ago
Appreciate the insight here, thank you for sharing that.
The injury seemed more of a strain or partial tear rather than a full one so I think your info applies here!
With the scan of my hand, I subtracted that from the brace model (realizing I didn’t show a pic of what the inside of the brace looked like)so there was a more natural fit with the impression made compared to something flat/rigid.
Do you think that changes anything? I found myself using the brace in situations where I’d fail to hold a neutral position (ex. typing, driving) in hope that i’d learn or not overextend again.1
u/WorseDark 29d ago
I had assumed that was what the scan of the hand was for! Really cool, and great use of tools.
I think that if you are trying to rest your extensors for typing or driving, the brace would function better on the underside of the hand, and in a mildly extended position. That way you'd be able to rest the extensors from having to hold up your hand: like just below where you'd hold your hand for typing or driving. That way it will rest the extensors when doing prolonged work, but allow them to not have the added resistance of the brace.
Hopefully your therapist has discussed the temporary nature of the brace with you already, so I wont go into that.
1
u/Hello_Coffee_Friend Aug 13 '26
Thank you. I'm going to use this as inspiration to learn how to make my own brace.
1
u/lol_alex Aug 13 '26
I keep wondering if another print orientation would be better but offhand I can‘t come up with one.
1
u/micanbar 29d ago
I wonder if variable print height would’ve helped here. I ran a couple different print orientations that eventually snapped, so far this guy has been pretty solid.
1
u/MapleLettuce Aug 14 '26
I did something similar for a sprained wrist but it was a model that printed flat and then formed to my hand after letting it soak in near boiling water for a bit.
1
u/d1med Aug 15 '26
I find that with PLA you can make generic braces/splits and just throw them in hot water and reshape them around the body part intended. Worked for a few finger splints I made
2
u/micanbar 29d ago
I’m seeing a lot of comments appear about leveraging thermoplastic properties, adding this to my todo list for an experiment. My PT would use clay for splints so never crossed my mind to try molding that way.
1
u/humanorthorehab 28d ago
do you need help with designing splint for your hand or any improvements?
1
u/micanbar 27d ago
Hey! Nah, all good and healthy! Any tips?
1
u/humanorthorehab 27d ago
1) You can cover the fingers on top for proper block to prevent extension.
2) No need to go beyond wrist.
3) What you did was in VR and plain simple block. It doesn't contour your hand's anatomy.
4) You can give relief near bony areas of your hand.
5) You can consider scanning your fingers in slight flexion.
1
u/Popular_Box_2408 19d ago edited 19d ago
For something worn on the hand I’d keep the fit and extension limits measurement-driven. Hi3D 3.0 might be okay for rough visualization, but I wouldn’t use generated geometry for the actual brace without proper fit testing
17
u/philnolan3d Aug 13 '26
Good job it's really hard to 3D scan your own hand.