Summary

Fully Adjustable Prosthetic

A one-size-fits-all 3D printed leg designed for small children

A fully adjustable, 3D-printed, lower limb prosthetic to improve long-term outcomes particularly for children and adolescents living with lower limb loss.

Introduction

After getting some feedback on Version 1, we’re excited to introduce Version 2.

To significantly increase the strength, we swapped out our plastic core with a steel thread core. Also, our aesthetically redesigned shin is now printed from a carbon fiber nylon blend.

Next, let’s move up the leg, to the socket of the prosthesis. Using TPU diamond-slotted flaps laced with a specialized cable and micro-adjustment dial system, you can easily and evenly fit and form the connection to any size or shape with a comfortable and secure attachment.

Now let’s move all the way down to our revamped, dynamically responsive feet. With this new and sporty design, we made sure you can easily swap them out with a different size or density anytime.

Finally, the leg now comes in three sizes, Child, Junior, and Young Adult. Each of which can have the height adjusted, with the goal of accommodating any size from small children to tall adults.

Important Notes

Please note that this thingiverse file comes with multiple different sized feet to accommodate different foot sizes. We have provided files for sizes 3, 5, and 7. Please print the size that works best for you! If you need sizes bigger than this, please visit the Junior size leg or Young Adult sized leg for additional sizes.

Bill of Materials

All of the non-3D-printed parts needed for the unit.

🔢 Qty	🔩 Hardware Part	📐 Dimensions
1	HIGH-STRENGTH 10.9 STEEL HEX SCREW	M14 x 2mm thread, 50mm length
1	18-8 STAINLESS STEEL KEY LOCKING INSERT	M14 x 2mm thread, 20mm install length
12	HEAT SET INSERTS FOR PLASTIC	M3 x 0.5mm thread, 3.8mm install length
4	HEAT SET INSERTS FOR PLASTIC	M4 x 0.7mm thread, 4.7mm install length
4	SOCKET HEAD HEX SCREWS	M3 x 0.5mm thread, 5mm long
6	BUTTON HEAD HEX SCREWS	M3 x 0.5mm thread, 6mm long
6	BUTTON HEAD HEX SCREWS	M3 x 0.5mm thread, 12mm long
8	SOCKET HEAD HEX SCREWS	M3 x 0.5mm thread, 25mm long
12	HEX NUTS	M3 x 0.5mm thread
4	SOCKET HEAD HEX SCREWS	M4 x 0.7mm thread, 16mm long
4	BUTTON HEAD HEX SCREWS	M5 x 0.8mm thread, 40mm long
2	BUTTON HEAD HEX SCREWS	M5 x 0.8mm thread, 50mm long
6	HEX NUTS	M5 x 0.8mm thread
1	VELCRO STRAP	47cm length
1	MICRO ADJ DIAL CABLE SYSTEM	1.2mm diameter cables
1	EVA FOAM W/ ADHESIVE BACKING	1/4" thickness, 1 sq/ft

Slicing and Printing

Material choice, Infill patterns, and densities are crucial for optimizing the prosthetic's strength and flexibility. While you do not have to follow these instructions exactly when slicing at home, these are the recommended materials, orientations, and slicing instructions that we used here at Incept 3D.

Step by Step Assembly

Step 1

Heat and Install M14x2mm threaded key lock inserts to Yth_Shin_Inner.
Install 4x M4x0.7mm-4.7mm length heat set inserts to Yth_Shin_Outer.

Step 2

Install M14x2mm-50mm long high tensile hex head bolt to the middle of Yth_Shin_Outer.

Step 3

Install 4x_M4x16 socket head hex screws to Yth_Cradle as shown.
Install 12x_M3x0.5mm-3.8mm length heat set inserts to Yth_Cradle sides.

Step 4

Install 2 4x-TPU_Flaps using 6x_M3x6 button head Hex screws.

Step 5

Install the Thigh_Cradle to the Knee_Support using 2x_M3 hex nuts and socket head hex screws.

Step 6

Place the Knee_Support on top of TPU_Flaps as shown (loops facing out) and install to the Yth_Cradle using 6x_M3x10mm bottom head hex screws.

Step 7

Install 4x_M5x40mm button head hex screws to the Dyna_Foot with the desired Foot Size. Secure the Dyna_Foot to the Ankle_Block using M5 hex nuts.

Step 8

Install 8x_M3x25mm socket head hex screws to the TPU_Foot_LFT and secure the two halves together over the Dyna_Foot using 8x_M3 hex nuts.

Step 9

Install 2x_M5x50mm bottom head hex screws to the bottom of Yth_Shin_Inner. Install the Foot to the Shin using 2x_M5 hex nuts.

Fully Completed

Additional Post Printing Details

Foam Backing

While these are wearable on their own, we recommend using adhesive backed foam listed in the Bill of Materials on the back of the TPU_Flaps and Knee_Support for comfort and a velcro strap to secure the Knee_Support

Lacing, Getting In and Out of your Prosthetic, and Lengthening and Shortening

For a video tutorial on how to properly lace up your prosthetic leg, getting in and out, and to lengthen and shorten your leg, please see here:

Fully Adjustable Prosthetic V2 - Child

Fully Adjustable Prosthetic