Establishing the Problem: Rationale

There is unmet need for transtibial prostheses for persons <18 years of age that are capable of growing with the minor; that is, the prosthesis is either easily replaceable or adjustable beyond what is currently provided, which must be replaced every 1 to 2 years when the child grows beyond the prosthesis’ range of adjustment or wears out the limb with continuous stress. A child will need frequent replacement of a transtibial prosthesis for two primary reasons: growth and activity.

According to the CDC and researchers at Worcester Polytechnic Institute, children between ages 2 and 14 may grow 5-10 cm per year. Although conventional transtibial prostheses are capable of adjustment--endoskeletal shanks can be adjusted by changing the internal piping, exoskeletal shanks can be adjusted incrementally with the addition of shims by a prosthetist, and shoe insert may be added for both types of shanks--these adjustments have their limitations, and the child will require a new prosthesis given how rapidly they grow, both in height and weight.

People under 18 years of age also tend to be very active, putting more strain on their joints and requiring a higher range of motion. With continuous use, either sustained moderate pressure (i.e. walking, standing, etc.) or intermittent pressure (i.e. jumping, running, etc.), the prosthesis will exhibit a weakened shank, wear on movable components, and a less aesthetically pleasing external finish.

Frequent replacement of the prostheses should not be a problem; replacements do exist for all four components of a below-knee prosthesis (ankle-foot assemblies, shanks, below-knee sockets, below-knee prosthetic suspensions), but patients and families face financial restrictions in most cases. Prostheses are expensive (usually upward of $5,000) and frequent replacement is burdensome. Patients who require frequent replacements often deal with restrictions from their primary third-party payer. In some cases, children are denied financial reimbursement from insurers and must decline a prosthesis that their families can’t afford.

Initials Concept Designs (printing soon)

First designs! These are going to be the first three designs printed. The next one to come will probably be something simulating the natural tibia-fibula design.

Adult Elliptic Pylon

Adult Elliptic Pylon
(with notes)

Adult Circular Pylon

Adult Circular Pylon
(with notes)

Adult Circular Straight Pylon
with Bows

Adult Circular Straight Pylon
with Bows (with notes)

Adult Circular Straight Pylon with Bows (cross section)

Open Hand Projects

If you're interested in prosthetic hand research, check out these articles:

http://www.eng.yale.edu/grablab/openhand/
http://www.openhandproject.org/
https://www.indiegogo.com/projects/the-open-hand-project-a-low-cost-robotic-hand

Cool Article: Kids outfitted with new hands made on 3-D printers

Within the past year, a child, Griffin Matuszek, was fitted with a function 3-D printed hand!
Read the article to find out more. This serves as proof that 3-D printing has effectively helped children with limb deficiencies. However, there is a big difference between a hand and a leg. While a hand is more mechanically intensive, a leg is under more physical stress due to weight. A hand is a good place to start, but further research must go into the limitations of 3-D material.

Also check out this article published by Fox News to learn more about Griffin Matuszek's story. This article goes a bit more into the potential for 3-D products in the medical industries, both the pros and cons. Check it out!

Article Review: Limb Prosthetics Services and Devices: Critical Unmet Need: Market Analysis

This article reviews the current--the year of publication is unknown, although the text indicates publication between 2009 and 2013--state of limb prosthetics services and devices in the context of the United States market: "The scope of this market analysis focuses on limb prosthetics in the United States." However, the study openly acknowledges that data are varying and hard to access, if accessible at all, so there are limitations on the study. 

"When a person becomes a limb amputee, he or she is faced with staggering emotional and financial lifestyle changes." There is a growing, "demand for restoring mobility and independence from amputees," and a growing "consumer base of amputees drives the market with demands for improvement in quality of life and innovation will address quality of life needs." However, this growing demand and "period of rapid technological advances in lower limb prostheses" has resulted in relatively constant satisfaction polls ("overall amputee satisfaction with the prosthesis has remained relatively constant, varying between 70-75% of those polled.") and an "estimated reduction in funding for amputee care of 20% compared to prior decades."

The economic downturn in 2009 "has exasperated the rate of commercial R&D for limb prosthetics innovation. All markets have been hit hard. Third party payers are more restrictive." Third party payers include Medicare, Medicaid, the U.S. Department of Veterans Affairs, and private third-party insurers. For children, this is reduced to just Medicaid--"a health insurance program jointly funded by federal and state governments providing health insurance coverage for certain persons in financial need, regardless of age"--and more importantly, private insurers. However, "Yearly third party health insurance caps on prosthetic services range from $500 to $ 3000 and lifetime restrictions range from $10,000 to one prosthetic device during a person's lifetime (from birth to death)."

These financial caps are insufficient to purchase anything but "lower priced products that are less effective." A below-knee prosthetic ranging from $5,000 to $7,000, "a patient can get a serviceable below-the-knee prosthesis that allows the user to stand and walk on level ground. By contrast, a $10,000 device will allow the person to become a "community walker," able to go up and down stairs and to traverse uneven terrain. A prosthetic leg in the $12,000 to $15,000 price range will facilitate running and functioning at a level nearly indistinguishable from someone with two legs."

Prices for remain high despite third-party payer caps and research and development for prosthetics designs. This pricing is largely due to prostheses not being produceable in mass quantities; "If one device could serve everyone, then prosthetics could be mass produced and costs reduced.  But limb prosthetics are produced in relatively small numbers and made of custom materials, with a variety of componentry. Sizes are different so each model may have six or eight variations depending on the needs of each patient."

With children, the greatest concern is the rate at which they grow and how to accommodate a child with a constantly will fitted prosthetic; "... children need more frequent replacements to keep pace with their growth. A child of twelve may grow four inches and gain twenty pounds in a year. A new limb prosthesis is needed." With financial caps set at $10,000, it is unlikely for a child to receive the devices they need to accommodate their growth. Most shockingly, "Some insurers also will readily reimburse for an amputation and secondary complications (including further amputation) stemming from inactivity, but they will limit or refuse to cover a prostheses replacement for an active amputee or a growing child," due to active amputees putting a lot of wear on the devices, which insurers are unwilling to reimburse, and children requiring many inevitable replacements.

"Diabetes and peripheral vascular diseases rank as the number one cause of amputation in the United States, where an average 185,000 amputations are performed annually, thus increasing the consumer base and presenting opportunities for service providers." 82% of those 185,000 amputations surgeries were due to Peripheral Vascular Disease and Diabetes.

Although "there is a direct correlation between age and the onset of diabetes and vascular disease, which are the leading causes of amputations," other causes of amputation include congenital disease and trauma (accidents and war-related ones specifically). Lawnmower accidents are exceedingly common in children; "Approximately 8,900 children receive amputations each year due to lawn mower accidents," which makes up approximately 4.8% of amputation surgeries in the United States. When focusing on children, it is also important to consider congenital diseases; “Birth defects result in a life long need for prosthetic devices… Every day in the United States, children are born with missing limbs, and teenagers suffer amputations as a result of accidents or cancer." As of 1996, 70,000 persons <18 years of age were living with limb loss.

A transtibial prosthetic, "is an artificial limb that replaces a leg missing below the knee. Transtibial amputees are usually able to regain normal movement more readily than someone with a transfemoral amputation [a leg missing above the knee], due in large part to retaining the knee, which allows for easier movement." If you would like to learn the details about either, click on this for details on below-knee amputations and below-knee prosthetics.

To read the article, follow this link:
http://www.nist.gov/tip/wp/pswp/upload/239_limb_prosthetics_services_devices.pdf

Cool article about 3D printing and prosthetics

I stumbled upon this article while researching; I don't know how credible the source is, but it's still a cool and relevant article. Check it out!  The Role Of 3D Printing In The Design And Manufacture Of Prosthetic Devices