How Ruijin Orthopaedic Institute Built a Production Workflow for Patient-specific Orthotics and Cutting Guides with AM Solutions from 3D Systems

The Shanghai Institute of Traumatology and Orthopaedics, established in 1958 by Shanghai Ruijin Hospital, has long recognized the importance of patient-centered care. The Institute faced several challenges in producing personalized devices. The staff turned to 3D Systems’ additive manufacturing solutions to set up a reliable production workflow for patient-specific orthotics and cutting guides, enhancing surgical precision, recovery times, and patient outcomes.

With an on-site manufacturing facility, the hospital leverages both traditional and 3D printing technologies to provide customized, cost-effective medical solutions, ensuring accessibility for patients of all financial backgrounds.

Let’s explore each challenge and how it was addressed.

Disclaimer: 3D Systems does not have regulatory clearance for the applications mentioned in this article.

For treating patients with flat feet Ruijin Orthopaedic Institute developed custom orthopedic insoles to provide optimal support, pressure distribution, and targeted correction. The engineers focused on refining the internal design of the insoles by designing sophisticated lattice structures to achieve this. The design was impeccably transferred to reality with the SLS technology from 3D Systems, as proven by rigorous tests by the Ruijin team. This personalized approach significantly improved treatment outcomes, ensuring better support and care for patients.

Custom insoles with 3D System's SLS Solutions 

The Ruijin Institute chose 3D Systems' SLS solutions due to their precision, efficiency, and versatile materials, especially nylon, valued for its flexibility, strength, and durability in orthopedic applications. Other benefits include:

• Complex Designs: Selective Laser Sintering (SLS) is known for producing durable and functional parts. Its self-supporting nature – where the product is built within a bed of powder – eliminates the need for additional support structures, enabling the creation of complex geometries. The SLS family printing solutions from 3D Systems excel in producing intricate lattice structures required for tailored pressure zones, crucial for achieving the purpose of custom insoles.
• Cost Efficiency for Batch Production: Thanks to large build volume of 3D Systems’ SLS printers, multiple insoles can be printed simultaneously, reducing production time and costs compared to other methods.  
• Seamless Finish: Parts printed with SLS solutions from 3D Systems have a uniform finish, which enhances comfort and aesthetic quality, important for wearable products.

The patient recovery braces previously used at the Institute faced significant challenges. Production times were lengthy, and the devices failed to meet patient-specific design requirements. Additionally, they lacked adequate air permeability, compromising comfort and functionality. The Ruijin Institute team advanced their efforts in patient-specific care by producing custom rehabilitation braces with the same SLS solutions from 3D Systems.

The design process for custom wrist brace started with 3D scanning to capture precise anatomical details. It also included a step where the team simulated stress distribution on the brace surface to ensure it could withstand wear and tear. Based on that, a grid structure was developed, and hollow areas were strategically increased to enhance thermal comfort while maintaining the necessary strength. Adjustable fasteners were integrated to allow the patient to modify tightness.

"The personalized wrist rehabilitation brace manufactured by 3D Systems’ SLS technology not only guaranteed safety and effectiveness but also showed the unparalleled matching degree while maintaining comfort of a traditional brace."

The hospital also produces custom rehabilitation devices and orthotics using digital design methods and SLS printing solutions from 3D Systems.

Traditional surgical methods for patients needing urgent total ankle replacement lengthy and exposed staff to excessive radiation. Clinicians were aware of the significant benefits of patient-specific cutting guides: improved outcomes, reduced operating times, lower overall costs. However, a few practical constraints had to be overcome: limited resources and the time-intensive production process, involving data collection, custom design, printing, and post-processing. The team needed a 3D printer that was not only fast, but also accurate and with superb parts finish. This time the SLA technology of 3D System's Figure 4® printer was utilized.

"Thanks to the excellent performance of the MED-AMB 10 material, the design turned quickly into reality. There is no complicated pre-print preparation for Figure 4®, it is easy and quick to operate. And it takes only 2 hours to complete the print"

In total ankle arthroplasty, precise tibia and talus osteotomy placement is crucial for proper joint motion and lower limb alignment. Traditionally, the procedure involves three positioning steps, four C-arm imaging sessions, and over three hours of operating time, which exposes staff to prolonged radiation. The Ruijin team addressed these challenges with a customized guide that accurately defined the osteotomy plane in a single C-arm session, significantly reducing surgical time and radiation exposure.

Using CT images, they digitally reconstructed and aligned the tibia, talus, and calcaneus to determine prosthesis specifications. A universal guide model was customized using Boolean operations with patient-specific bone data, creating a precise cutting guide. This guide, 3D printed alongside a matching bone model, enabled accurate and efficient surgical preparation.

How Figure 4® Helped to Maximize the Performance of the Cutting Guide 

1. During the design process, the cutting guide was refined using Boolean calculations based on the tibia and talus, creating a complex inner surface for a precise bone fit. The Figure 4® printer ensured high surface accuracy and an optimal fit. 

2. The holes in the guide plate were meticulously designed to precisely match the Kirschner needle and ensure accurate positioning during surgery. After the guide was printed, cleaned, and cured, it fit seamlessly with the Kirschner needle.

 3. Before entering the OR, the guide plate underwent strict sterilization. The biocompatible material MED-AMB 10 once again demonstrated its reliability, material stability necessary for such procedures, and safety in the operating environment.

In summary, the Ruijin Institute has fully embraced patient-specific care, achieving enhanced patient outcomes. Their innovative application of 3D printing highlights the extraordinary versatility of additive manufacturing. By employing such advanced techniques as designing lattice structures for insoles and personalized braces, the team has effectively tackled critical challenges in rehabilitation and surgery, significantly improving functionality, comfort, and overall quality of care for patients.

This case demonstrates how integrating 3D printing labs at the point-of-care can enhance surgical precision, accelerate recovery, and reduce revision rates. The Ruijin Institute's approach highlights the transformative impact of 3D printing, setting a new standard for personalized medical devices and more efficient surgical workflows.