A miniature steerable end-effector for application in an integrated system for computer-assisted arthroscopy

Arthroscopic techniques are very popular in orthopaedic surgery for intervention on articular joints, especially on the knee. From an engineering viewpoint, current arthroscopic techniques can be improved in two ways: a) by augmenting visual information for the surgeon; b) by improving existing instrumentation. In our laboratory we are addressing both problems by developing an integrated system for computer-assisted arthroscopy. In this paper the procedures and instrumentation currently adopted for arthroscopy, and the limitations of both, are described first. Then the main characteristics of the integrated system we are developing are presented. The design requirements for new and better instruments for arthroscopy are discussed in detail and the fabrication and testing of a prototype of shape memory alloy-based actuator developed for steering the distal part of an arthroscope are discussed. The prototype steerable end-effector can rotate of ±90° and exert a maximum force at the tip of about 1N