Design of a Compliant Steerable Arthroscopic Punch

Abstract

Meniscectomy is a medical procedure where ruptured meniscal tissue is removed within the knee joint. The conventional cutters fail to reach the entire meniscus. Therefore, the focus of this study is to create a steerable joint, which allows sideway steering of the tip to increase the reachability within the knee joint. Additionally, the steerable joint is required to be robust to transmit a cutting force of up to 190 N. The mechanism design is divided into the functions: steering and actuating cutting mechanism. The most promising solution of these functions was combined and resulted in the use of a crossed configuration of a compliant rolling-contact element for the instrument joint. Flexural steering beams actuate the rotation of the joint using the principle of a parallelogram mechanism. The prototype has a range of motion of +25 deg and −22 deg with a steering stiffness at the handle side of 33 N mm/rad. An axial load of 200 N on the tip corresponded with a parasitic deflection of 4 deg. This unique type of steerable instrument shows potential to be functional in meniscectomy due to the great robustness of the joint.