# Three-dimensional imaging of the forearm and hand: A comparison between two 3D imaging systems

## TL;DR

This paper compares two 3D imaging systems for creating personalized 3D printed splints for forearm fractures, finding the new SPENTYS system accurate and feasible for clinical use.

## Contribution

The study introduces and validates a new portable 3D imaging system (SPENTYS) for generating patient-specific splints with high accuracy and usability.

## Key findings

- The SPENTYS system showed a mean absolute difference of 0.44 mm compared to the reference 3dMD system.
- Both systems had intersystem and repeatability differences within the acceptable 1 mm threshold.
- Professionals found the SPENTYS workflow easy and effective for clinical use.

## Abstract

The conventional treatment for distal radius fractures typically involves immobilization of the injured extremity using a conventional forearm cast. These casts do cause all sorts of discomfort during wear and impose life-style restrictions on the wearer. Personalized 3D printed splints, designed using three-dimensional (3D) imaging systems, might overcome these problems. To obtain a patient specific splint, commercially available 3D camera systems are utilized to capture patient extremities, generating 3D models for splint design. This study investigates the feasibility of utilizing a new camera system (SPENTYS) to capture 3D surface scans of the forearm for the design of 3D printed splints. In a prospective observational cohort study involving 17 healthy participants, we conducted repeated 3D imaging using both the new (SPENTYS) and a reference system (3dMD) to assess intersystem accuracy and repeatability. The intersystem accuracy of the SPENTYS system was determined by comparison of the 3D surface scans with the reference system (3dMD). Comparison of consecutive images acquired per device determined the repeatability. Feasibility was measured with system usability score questionnaires distributed among professionals. The mean absolute difference between the two systems was 0.44 mm (SD:0.25). The mean absolute difference of the repeatability of the reference -and the SPENTYS system was respectively 0.40 mm (SD: 0.30) and 0.53 mm (SD: 0.25). Both repeatability and intersystem differences were within the self-reported 1 mm. The workflow was considered easy and effective, emphasizing the potential of this approach within a workflow to obtain patient specific splint.

Within fracture care, conventional casts often induce patient discomfort and lifestyle restrictions, motivating our exploration of innovative alternatives. A promising solution involves the development of patient-specific 3D printed splints. These splints may offer enhancements such as improved aeration, reduced weight, and the ability to participate in water-related activities. The production of 3D splints typically starts with 3D imaging of the injured limb, which serves as input for subsequent splint design and the 3D printing process. Our research focuses on this initial phase by evaluating a new 3D imaging device.

Specifically, we investigate the feasibility of SPENTYS, a new portable 3D camera system tailored for surface scans of the limbs. Through a comparative analysis involving 17 healthy participants, we assess the SPENTYS accuracy and repeatability against a standard reference system within our hospital (3dmd). The results highlight SPENTYS’s accuracy, with a mean absolute difference of 0.44 mm compared to the reference system. Furthermore, positive feedback on usability from professionals underscores its potential in clinical practice.