An optimal de Quervain's tenosynovitis splint with ergonomic thumb support and evenly distributed pressure.

Splinting is a conventional treatment for de Quervain's tenosynovitis (dQt). However, existing splints have problems such as excessive thermal discomfort and poor fit, which have been pointed out in previous studies. This study proposes a new functional splint consisting of both hard and soft materials with the aim of providing wear comfort with a good fit and sufficient stability of the injured hand. Thumb support of the splint is an important component that controls and protects the affected thumb. To develop an ergonomically shaped thumb support, 16 participants with dQt were recruited for three-dimensional (3D) scanning of their hands. The angles of the wrist and the curvature of the thumb were measured using computer software, and the results were used as a reference for the design of the prototype supports. Excessive pressure on particular regions, such as bony areas, may cause discomfort or pain. To ensure the wear comfort of the proposed splint, a finite element model (FEM) was built to simulate the wear process of the splint and hence to predict the pressure distribution exerted from the splint onto the hand of the wearer. The simulated results show that the pressure is evenly distributed over the hand, indicating that patients are likely to wear the proposed splint comfortably during their treatment period.