Methods: Design Goal

3D-Printed Miniature Prosthetic FingersBiomechatronics Development Laboratory

CU Denver|Anschutz Medical Campus

Stephen Huddle, Jacob Segil, Stephanie Lorelli, Richard WeirEmail: 3D-printing@ucdenver.edu

Location: CHC Research Institute Lab: Room A0978

Discussion: Novel Ratchet Mechanism

ReferencesThere are approximately 500,000 people

living with minor upper limb loss in the

USA [1],[2]. While the field refers to these

types of amputation as ‘minor,’ it can be a

severe disability, especially if the

amputation involves the thumb and/or

multiple digits. Amputation can cause

physical, psychosocial, and economic

damage to an individual and can lead to

depression, anxiety, loss of self-esteem,

and social isolation [3],[4]. While the

number of individuals with partial hand

amputation is 10 times more than all other

categories of upper limb amputation

combined, the state of available

technology for this underrepresented

patient population is relatively poor. We

seek to improve options for prosthetic

fingers to be used on a daily basis.

The novel ratcheting mechanism allows

for intuitive one-handed use: Since

these are mechanical digits, finger

flexion is achieved by using the

contralateral hand or by pressing the

digits against a surface. The opposing

surface is used to flex and lock the

Point Digit into 10 distinct positions.

Opening is achieved by pressing the

release button (like a ball-point-pen

lock/unlock mechanism) or pressing

until the digits are fully flexed at which

time they will spring open. The

miniaturized prosthetic finger will

incorporate more distinct steps to allow

for additional grip positions.

Create reliable and robust passive

prosthetic fingers for women, children,

and pediatric populations with partial

hand amputations. These 3D-printed

metal prosthetic fingers will be of

anatomically appropriate size and

weight while maintaining functional

integrity.

Background and Significance

[1] K. Ziegler-Graham, E. J. MacKenzie, P.

L. Ephraim, T. G. Travison, and R.

Brookmeyer, “Estimating the prevalence of

limb loss in the United States: 2005 to

2050,” Arch. Phys. Med. Rehabil., vol. 89,

no. 3, pp. 422–429, 2008.

[2] M. P. LaPlante and D. Carlson,

“Disability in the United States: Prevalence

and Causes, 1992. Disability Statistics

Report 7.,” Aug. 1996.

[3] J. Davidson, “A comparison of upper

limb amputees and patients with upper limb

injuries using the Disability of the Arm,

Shoulder and Hand (DASH),” Disabil.

Rehabil., vol. 26, no. 14–15, pp. 917–923,

Jul. 2004.

[4] H. Burger, T. Maver, and Č. Marinček,

“Partial hand amputation and work,”

Disabil. Rehabil., vol. 29, no. 17, pp. 1317–

1321, Jan. 2007.

Miniature prosthetic

finger side by side

comparison with a

5.8mm tall finger.

The finger on the far left is the 80mm Point

Digit from Point Designs LLC which is the

smallest size currently available. The

fingers scale down to 55mm by increments

of 5mm showing a range of new miniature

sizes.

Full set of miniature prosthetic

fingers.

Raw 3D-printed

steel parts still

attached to build

plate.

Results: Prototypes

1 I01 RX002830-01A1(Weir): Artificial

Digit Replacements for Women

Veterans with Individual Digit Loss

Project to develop a ratcheting prosthetic finger

using 3D Metal Printing for women veterans with

loss of one or more fingers.