No matter which biomechanical principles we utilize to prescribe and produce custom foot orthoses for our patients, we all must admit that prescribing footwear interventions is not like prescribing medication – no one knows the right dose. How stiff should the shell be? How high should the arch be? How much rearfoot or forefoot posting is optimal for that specific patient? An experienced practitioner can make reasonable inferences and often produce a beneficial device on the first try. But we must admit that this doesn’t always happen. So, what if we had a method to easily and at low cost change the dose after assessing how our patients respond? Or, what if we could produce multiple versions of a custom device to start and then have the patient select the most comfortable option after making comparisons? We now have that method via accessible and affordable digital technologies.
The technologies enabling this revolution include iPhone scanning apps, 3D orthotic design software and in-clinic 3D printers. Used together, they have opened the door to a dose-response approach to foot orthotic therapy. Clinicians can now scan, design, and produce custom foot orthoses in their clinic, at 50% to 75% lower cost than a traditional orthotic lab. The time and cost savings alone are worth making the transition, but the elevated service to the patient is achieved via rapid iteration.
Rapid iteration is a term used in product development that refers to a process of making incremental changes rapidly to improve the design and function of a product. In the context of foot orthoses, rapid iteration provides the opportunity for a dose-response approach to treating lower extremity conditions. Orthoses can be dispensed to a patient and then, based on how they respond (both in terms of symptom relief and comfort), the dose can be easily revised digitally and the devices reprinted. For example, if a patient with plantar heel pain perceives the orthoses to be too hard or the arch too high, the digital model can be modified with a lower arch and printed softer with just a few clicks of the mouse. The digital design change takes a couple of minutes, and the revised orthosis can be ready in a matter of hours.
Continuing with the dosing analogy, just as we want to use the minimal effective dose when prescribing medications, we should also strive for the minimal effective dose of orthotic devices. So, instead of making a maximum dose orthotic because we don’t want to incur the extra cost and time of remaking it, we can now prioritize a minimal effective dose device and incrementally increase the dose, if necessary, based on how that patient responds to the first dose.
Alternatively, multiple versions (or iterations) of the orthoses could be printed prior to dispensing. For example, one could print multiple pairs with varying arch height and/or shell density and allow the patient to try on all versions and select the most comfortable option. Or, for athletes who wear cleated footwear, one could easily make a device scaled to cleats and another device for training shoes. Again, all for much lower cost and faster turnaround time. The author has found that elite athletes are especially appreciative of this new approach.
To make the digital process work, you need the following equipment: iPhone/cellular phone, application software, technology partner, your computer, and easy access to a 3-D printer.
Step 1. Open app and scan patient’s feet using iPhone
Step 2. Upload anonymized patient scan data to technology partner
Step 3. Receive processed mesh model of foot and digital orthotic file via online folder
Step 4. Digitally design the device on your laptop
Step 5. Print orthoses in clinic
Step 6. Dispense orthoses
Step 7. Revise orthoses based on patient’s response
Step 8. (If necessary) Repeat steps 4 through 7 as needed
The start-up costs for in-house 3-D printing are minimal, especially for technology that elevates patient care and dramatically lowers per-pair costs. The app and design software are provided at no cost from the author’s 3D technology partner. Rolls of printing filament cost approximately $100 and can print up to 10 pairs per roll. Printers currently start at approximately $750. So, for less than $1000 a clinic could produce foot orthoses. The 3D partner lab the author works with charges a one-time $20 to $40 modeling fee per patient and the devices require approximately $7 in filament material. So, the first pair of orthoses per patient would be approximately $27 to $47 but any additional pairs for that patient would incur just the cost of filament. As you can see, printing multiple pairs is still dramatically less costly than one pair from most traditional orthotic labs.
One printer can produce 1 pair of orthoses in approximately 5 hours. The printers run unattended so a print job could run while the clinician sees patients, run overnight and a finished pair would be ready for dispensing the next morning. One printer could produce 2 – 3 pairs per day. The author scaled up by adding one printer at a time as volumes increased and now has 2 printers in clinic and 2 printers at home so he can run them 24/7 if needed. The 4 printers can produce 8 – 12 pairs per day and run on weekends if needed.
This technology replaces a highly manual workflow with a streamlined digital workflow. For experienced clinicians who are already using smartphones and laptops, the learning curve is very smooth. The 3D printers can be unboxed and running in about an hour with easy-to-follow video tutorials, and they require minimal maintenance. The design software uses the same thought process one would use filling out an orthotic prescription.
Another advantage of this process is that a clinician does not need to fire their orthotic lab and immediately start producing all their own devices. The author started by producing a few orthotics a week in clinic while still using a traditional lab and gradually phased out the lab as his comfort level grew.
The other benefits include precise duplication of devices for those who want multiple pairs and much greater ease scaling a device to specific footwear including skates, ski boots, cleats, and even the ability to 3D print sandals.
In essence, 3D printing revolutionizes foot orthotic therapy by empowering clinicians with a dose-response methodology, facilitating rapid, in-clinic iteration and customization that was previously impractical. This digital approach dramatically curtails costs and production times compared to conventional methods, enabling easy modifications and the creation of multiple device versions based on patient feedback and specific needs, such as varying footwear. With minimal startup expenses, user-friendly design software, and low material costs, the transition to 3D printing is both accessible and scalable for clinics. This technological advancement not only allows for precise device duplication but ultimately elevates patient care by delivering highly personalized, effective, and timely orthotic solutions, offering an unprecedented level of service.
Paul Langer, DPM, is a podiatrist practicing with Twin Cities Orthopedics. He is the author of Great Feet for Life, serves as an adjunct faculty at the University of Minnesota Medical School, is a partner in Fleet Feet Minneapolis, and is the medical director of OLT Footcare.