Proper human gait is a complex orchestration of balance, strength, and mobility, all hinging on the integrity of the foot and ankle. Even small disruptions to the hindfoot, particularly the calcaneus and heel pad, can significantly impair walking, balance, and posture.
The implications extend beyond musculoskeletal discomfort—abnormal gait mechanics can cascade into long-term consequences like hip misalignment, back pain, and joint deterioration. For individuals suffering from partial heel loss, achieving a return to functional and pain-free walking can feel like a distant hope. Conventional approaches such as shoe inserts or off-the-shelf orthotics work well for many cases, but for some, these approaches fall short, especially when patients need barefoot mobility or require something more durable.
This article describes a recent clinical case where a barefoot-compatible, patient-specific prosthetic heel was fabricated using a novel approach integrating digital scanning, 3D-printed molds, and biocompatible heat-cured rubber (HCR). Additionally, it examines how 3D printing is being implemented in clinical practice and how this technology is poised to transform O&P.
Case Background
The case involves a 23-year-old woman who experienced a serious calcaneal infection in 2023 after stepping on a sea urchin. Following multiple surgical debridements, she was left with partial loss of the calcaneus and surrounding fat pad on her right foot (Image 1). Though her wound had healed, the structural and functional damage persisted. Specifically, the loss of heel tissue resulted in approximately a 5mm reduction in hindfoot height (Image 2), moderately impairing her gait. She was unable to perform a proper heel strike or transition through midstance, limiting her ability to walk comfortably—even in supportive footwear.
At the time of her initial consultation, the patient was using a shoe insert that included a custom heel build-up based on the traditional crush box method. While this solution provided some degree of symmetry and relief, it was restrictive: The insert confined her to specific types of shoes and did not address her desire to walk barefoot, a preference shaped by her lifestyle. It was clear that a more innovative and personalized solution was necessary.
Digital Workflow and Fabrication
The design and fabrication process began with a detailed scan of the patient’s right foot using a white-light 3D scanner (WillowWood Omega, 581348) with 1mm resolution. To ensure accurate reconstruction, digital tracking markers and reference photos were employed. The left foot was also scanned to serve as a visual and anatomical comparison.
After scanning, the data was cleaned in VXelements 6 (the software associated with the Omega scanner) and exported as a binary STL file. The model was further refined in Autodesk MeshMixer, where it was aligned to the cardinal planes and digitally trimmed. The final heel prosthesis was designed to terminate just proximal to the fifth metatarsal, preserving mobility while maximizing support. The design included a snug fit (-1mm offset) and matched the contralateral heel in thickness and contour, ensuring both functional and cosmetic symmetry.
Once the positive model was completed, a two-part negative mold was created, incorporating alignment pins for accuracy. The mold was sliced using PrusaSlicer and printed in PLA on a Creality Ender 3 printer with 80 percent infill to ensure rigidity and heat resistance. The surface was sanded smooth, and three coats of mold release (Smooth-On Universal Mold Release) were applied.
Elkem Silbione HCRA 4530 was selected for the prosthetic material due to its biocompatibility, mechanical durability, and proven use in anaplastology. Equal parts A and B were milled into a 3mm sheet, pressed into the mold, and subjected to a two-stage heat cure process: 170 degrees Fahrenheit (F) for one hour, followed by an additional 18 minutes at 170 degrees F and three minutes at 200 degrees F to complete the vulcanization. Given that the only fabrication tools involved a 3D printer and an oven, and the material is safe to use without any noxious fumes, most of the fabrication was performed in the clinician’s home kitchen. Three prototypes were made, differing in thickness.
Fitting and Outcome
At the fitting appointment, the prosthesis was applied using a plantar fasciitis sock to help hold it in place. The patient immediately reported a sense of comfort and security, with only mild pressure initially—no hotspots or voids. She was able to ambulate barefoot with a normalized gait pattern for the first time since her injury. Her gait cycle, from heel strike to toe-off, showed dramatic improvement in symmetry and fluidity. She also felt like she could perform weighted squats, as the material did not significantly deform under load, something she never felt comfortable with in her shoe insert.
Her initial reaction spoke volumes: “This feels like a part of me, not just a material I am walking on.” At one-month, two-month, and three-month follow-ups, the prosthesis remained fully intact, with only minor yellowing—a cosmetic change without functional consequences. There were no signs of material breakdown, tears, or performance loss.
Clinical Significance and Broader Application
This case highlights a practical use of 3D printing and advanced polymers in personalized prosthetic care. Rather than adapting the patient to available devices, we adapted the device to the patient. The barefoot-compatible design offers a viable alternative to traditional shoe inserts, particularly for patients with footwear limitations due to culture, climate, or lifestyle. Furthermore, this solution is reusable, waterproof, and can be worn during a wider range of daily activities.
The strength of this approach lies in its interdisciplinary integration: We combined clinical evaluation, 3D scanning, computer-aided design (CAD), additive manufacturing, and materials science into a unified workflow. Each element, on its own, has been used in O&P to varying degrees. But when synthesized, they create a powerful method for producing patient-specific solutions with a high degree of anatomical and functional accuracy.
Since the clinic already owned the scanner, MeshMixer is a free application, and the clinician owned an inexpensive 3D printer, the total cost of this prosthesis included only the cost of the material (approximately $100), and the subsequent consumables (PLA plastic, mold release, sandpaper, etc.). Mistakes were learned from the initial prototypes until successful iterations were produced.
Implementing 3D Printing in the Clinic
In our clinical setting, the integration of 3D printing has been both challenging and rewarding. Due to our fabrication limitations within the hospital, most of our devices are fabricated elsewhere; therefore, by using 3D printing, we can return to in-house fabrication. Initially, the technology was met with skepticism in the clinic—concerns about durability, cost, and unfamiliarity slowed adoption. However, as we began to demonstrate its utility in select cases like this one, interest and support grew.
We started by identifying cases that could benefit from custom solutions outside the scope of traditional manufacturing: partial foot losses, unusual deformities, pediatric anomalies, and cosmetic considerations. After setting up a basic 3D printing lab within the clinic—comprising a scanner, a desktop FDM printer, and CAD software—we were able to control the full fabrication cycle in-house.
This capability offered multiple advantages:
- Rapid prototyping: Iterations could be produced in hours, not weeks, at low cost.
- Customization: Devices were digitally sculpted to the patient’s anatomy, not just general templates.
- Cost efficiency: Once equipment was in place, material costs were minimal compared to outsourcing.
Challenges included managing print failures, maintaining equipment, and training staff in digital design. However, the learning curve proved worthwhile, and there are many guided tutorials on YouTube for digital sculpting and 3D printing. The more we used it, the more we discovered new applications—from mold fabrication and flexible prostheses to temporary sockets and alignment jigs. As a member of the American Academy of Orthotists and Prosthetists (Academy) CAD/CAM Society, not only did I have resources to overcome obstacles, but I can also share my successes for the betterment of the Society.
Widespread Potential
Looking ahead, 3D printing is poised to reshape O&P on multiple fronts:
- Accessibility: Clinics in underserved or remote regions could fabricate devices locally using low-cost printers and digital files shared over the internet.
- Materials science advances: New materials are being developed with improved mechanical properties, antimicrobial surfaces, and embedded sensors—broadening the possibilities for functional, smart prostheses.
- Hybrid manufacturing: Combining traditional lamination with 3D-printed reinforcement elements can yield lightweight, high-strength devices with enhanced biomechanical performance.
- Sustainability: On-demand fabrication reduces waste and storage costs. As biodegradable and recyclable polymers become more common, the environmental impact of production may also decrease.
The traditional mold-and-cast workflow has worked well for decades and serves as an important foundation as more digital techniques are developed. As clinical fabrication becomes more digital, it broadens the field to places where traditional workflows or devices are suboptimal, opening doors for people with limb loss and limb difference to receive appropriate prostheses worldwide.
Conclusion
The successful design and implementation of a custom-molded heel prosthesis for a woman with partial hindfoot loss demonstrates how 3D printing and modern materials can restore not just gait, but independence and quality of life. By leveraging digital workflows, clinicians can create more personalized, functional, and aesthetically appropriate solutions than ever before, all while remaining cost-effective.
As someone working to integrate these tools into everyday clinical practice, I’ve seen firsthand how 3D printing can shift the paradigm—from reactive care to proactive customization. We are still in the early stages of this transformation, but the trajectory is clear. With continued investment in training, materials research, and interdisciplinary collaboration, the future of prosthetic care will not just be hand-built—it will be digitally forged, one layer at a time. I have found that the Academy CAD/CAM Society is a place of like-minded individuals, not intending to rid our practices of a traditional workflow but to adapt what we know to the digital world in order to provide better patient care.
Andrew J. Miller, BME, MSPO, CPO, is a practitioner at MUSC Health Prosthetic and Orthotic Services, South Carolina, and a member of the Academy CAD/CAM Society.
Academy Society Spotlight is a presentation of clinical content by the Scientific Societies of the Academy in partnership with The O&P EDGE.
