Praxis Prosthetic Leg
Additional Media
The Challenge
Sena Institute of Technology wanted a cutting-edge 3D printing course for Ghana. I proposed designing a prosthetic leg as the showcase project: something societally useful and technically compelling. Transtibial prosthetics cost thousands in the US and require skilled labor even in low-cost models like the Jaipur Foot. The goal was to create a system enabling mass customization with minimal skilled labor, material waste, and cost.
What I Built
Prosthetic System (inspired by Jaipur Foot + MIT prosthetic foot):
- Socket: Auto-generated from 3D scans; novel C-channel attachment system for tool-free cover installation
- Foot: Parametric web generator based on MIT's algorithmic approach—input measurements, download print-ready file
- Modular Pylon: Accepts any metal pipe diameter/shape (eliminates specialized supply chain, Jaipur Foot principle)
- Integrated Cover: Auto-generated with user image customization via displacement mapping; evolved into standalone parametric covering system compatible with existing prosthetic legs, allowing users to easily customize look and fit
- All components: support-free printing, optimized layer orientation, zero waste, consumer-grade machines (~$1,500)
- Key advantage: Mass customization with less skilled labor, less waste, less material than both Jaipur Foot and US prosthetics
Distributed Custom Manufacturing System (DCMS):
- Web platform connecting remote manufacturing cells, expert modification, and local production
- Workflow: patient scanned locally → data sent to remote experts → automated tools generate design → manufactured on-site
- Standardized equipment specs for consistent quality across locations
- 5 web-based automation tools (socket generation, rectification, foot generator, pylon calculator, image customization)
- Physical scanning apparatus with calibrated compression bag mimicking body weight on limb
Infrastructure:
- Partnership with MIT Fab Foundation and Br. Tarcisius Prosthetics & Orthotics Training College (Ghana)
- Comprehensive patent application drafted covering DCMS architecture, prosthetic innovations, and parametric covering system (never filed due to cost)
Result
- Built functional prototype system (~$200 cost vs ~$5K traditional prosthetics). Validated technical approach with medical partners. Successfully demonstrated mass customization with minimal skilled labor—superior to both Jaipur Foot and US models in cost, waste, and manufacturing efficiency. Parametric covering system provided standalone product opportunity for existing prosthetic users.
- Failed to scale: prosthetic was too cheap for prosthetists to profit under insurance reimbursement models, eliminating adoption incentive for practitioners who prescribe devices. SIT faced financial difficulties. Attempted Ukrainian pivot during conflict: no partnerships secured due to similar lack of profitability for prosthetists.
- Released designs as open-source. Patent never filed ($10K+ cost). Key learning: disruptive pricing in gatekeeper-controlled markets requires redesigning the economic ecosystem, not just the product. Technical superiority proved insufficient without viable distribution economics.