DESIGN OF AN ARTICULATING NON-INVASIVE JOINT DISTRACTOR FOR METACARPOPHALANGEAL JOINT OF THE THUMB

Abstract

There is no specific distraction device available for the metacarpophalangeal joint (MCPJ) of the thumb. Joint distraction is required to facilitate the implantation of MCPJ spacers. In addition, expanding the joint space is essential for MCPJ arthroscopy. For these reasons, a novel device has been designed to create some space in the MCPJ. This articulating joint distractor uses a finger trap to apply the distraction force to the thumb and a strap to fixate the hand. There is the possibility to flex the thumb while maintaining the distraction force. In a first cadaveric experiment, we have determined that the force required to create 2 mm of distraction is approximately 30N. A prototype of the articulating joint distractor has been built and was tested during a second cadaveric study. As a result of the second cadaveric experiment, the desired functions of the prototype have been validated. By adjusting and optimizing the design to minimize the risks found partly during the experiment, the final design of the non-invasive MCPJ distractor has been realized.