Prosthetic hands for war-wounded children
A child who loses a hand in a war zone is rarely near a prosthetics clinic, and a commercial hand costs thousands of dollars. The question here is how far a desktop 3D printer, a scan and a parametric design can close that gap.
Three grasps out of thirty-three
The 2021 study took the most widely used open design, the e-NABLE Raptor Reloaded, worn by more than 1,500 people in 40 countries, and tested which of the 33 human grasp types it can do. It managed three. Try them here, swap the pins for soft joints, and shrink the hand to a child's size.
Grasp
The wearer flexes the wrist to pull the cables and close the fingers; elastic cords open them again.
Joints
Printed phalanges on pins rest flat, with the palm fully open.
Hand length 160 mm
The objects keep their real size. A parametric design rescales every part from a few measurements of the child's hand.
From a scan to a limb that matches
A prosthesis that looks like the missing part helps the wearer pass unnoticed, which patients say matters early on. The method started with one finger at NUS and grew into a full arm at Qatar University.
- ScanCT images of the affected and the healthy side
- MirrorThe healthy side, flipped, gives the shape and size
- DesignCAD of the socket and of moulds for the skin
- PrintMoulds and support bone on a desktop printer
- CastSilicone skin cured around the bone
- ShipSent to the patient for fitting
A finger made by email
A woman who had lost her ring finger at the middle joint 18 months earlier sent CT data over the internet. The finger was designed, cast in silicone around an artificial bone and posted back, so she never had to sit in a clinic for impressions.
A whole arm, within a third of a millimetre
The socket scored 0.95 Dice and 0.46 mm. The patient found the fit and the shape desirable.
How long a printed finger lasts
Finite element models of the finger, checked against tensile tests of the filament, gave the number of grasps before fatigue failure. At 50 grasps a day, a PLA finger carrying 15 N lasts about four years. ABS breaks outright above 10 N. Hover a load to see the cycles.
Source: Frontiers in Robotics and AI, 2021, Table 8. The raw data are on Data in Brief.
What a hand costs
The cost model counted a US$2,800 printer spread over 10,000 hours, 130 g of PLA at US$43 a kilogram, cables, elastic cords, a part-time technician, printer maintenance and 17 hours of electricity per hand. The printed hand is two orders of magnitude cheaper than a commercial one. The scale is logarithmic.
Softer joints, a natural rest, and training at home
Flexible joints
Elastomer joints replaced the printed pins to make the hand tougher. Because the hand can no longer rest flat, its rest angles were copied from a relaxed human hand.
Scanning in the camps
CT scanners rarely reach refugee settlements. Low-cost commercial imaging sensors and open image-processing tools produced limb models good enough to design from.
Training in extended reality
About a quarter of adults reject their upper-limb prosthesis (26% body-powered, 23% electric). A review of 42 studies on VR and AR training found that 71% of the larger trials recruited no amputees at all.
Parametric and soft
A parametric artificial hand with several grasp modes received a jury special mention at the ICSR 2024 robot design competition. A 2025 case study gave a child-sized hand silicone joints and servo motors and compared its range of motion with a human hand.
Papers, grants and a patent
12 papers
- 2025Assessing the Mobility of a Prosthetic Hand Featuring Soft Silicone Joints for War-Wounded Children: A Case Study
QU2025 47th Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC) - 2025Parametrically-Designed Artificial Hand with Multifunctional Grasps
QULecture Notes in Computer Science - 2021Suitability of the Openly Accessible 3D Printed Prosthetic Hands for War-Wounded Children
QUFrontiers in Robotics and AI, 31 citations - 2020Image Processing of 3D Scans for Upper Limb Prosthesis of the War-Wounded
QU2020 IEEE 20th International Conference on Bioinformatics and Bioengineering (BIBE), 3 citations - 2019Design and Analysis of Flexible Joints for a Robust 3D Printed Prosthetic Hand
QU2019 IEEE 16th International Conference on Rehabilitation Robotics (ICORR), 27 citations - 2019Data for benchmarking low-cost, 3D printed prosthetic hands
QUData in Brief, 12 citations - 2018A Method for 3-D Printing Patient-Specific Prosthetic Arms With High Accuracy Shape and Size
QUIEEE Access, 32 citations - 2018Slip suppression in prosthetic hands using a reflective optical sensor and MPI controller
QU2018 IEEE Biomedical Circuits and Systems Conference (BioCAS), 5 citations - 2017Toward 3D Printed Prosthetic Hands that Can Satisfy Psychosocial Needs: Grasping Force Comparisons Between a Prosthetic Hand and Human Hands
QULecture Notes in Computer Science, 10 citations - 2016Towards enhanced control of upper prosthetic limbs: A force-myographic approach
QU2016 6th IEEE International Conference on Biomedical Robotics and Biomechatronics (BioRob), 9 citations - 2016Fault tolerant tactile sensor arrays for prosthesis
QU2016 6th IEEE International Conference on Biomedical Robotics and Biomechatronics (BioRob), 4 citations - 2011Patient-Specific Prosthetic Fingers by Remote Collaboration–A Case Study
NUSPLoS ONE, 27 citations
Grants
- 2026Speech-based Prosthetic Hand Control for War-Wounded Children
US$29,578 · QRDI Council · Primary Research Mentor - 2022A Comprehensive System for Clinical Rehabilitation of Upper-Limb Amputees in Virtual Reality
US$297,613 · Qatar University · Lead Principal Investigator - 2019Amputee-Driven Design and Development of Upper Limb Prosthesis using Virtual-Physical Methodologies
US$288,000 · Qatar University · Lead Principal Investigator - 2018Extreme Reverse Innovation Process for the Delivery of Upper Limb Prosthetics via Digital Human Modelling, 3D Printing, and User Acceptance Surveys to Refugees
US$82,384 · Qatar University · Lead Principal Investigator
Patent
- 2022Multifunctional tooling apparatus with non-anthropomorphic construction
US 11,229,534 B2