University Technologies International, Inc.

Norman S Schachar

Nigel G Shrive

Cyril B Frank

Erich Damson

Fred Lhenen

Roger W McPherson

A device and method for the measurement of stiffness of cartilage, specifically intended for arthroscopic use. An tissue softness probe is formed from a stiff shaft and flexible shaft, and strain gauges continuously measure the load in the stiff shaft and the deflection of the flexible shaft as they are displaced into cartilage. The stiff shaft and flexible shaft extend away from a probe body beside each other. The stiff shaft is semi-circular in section at one end with a flat side extending along the shaft at that end, and the flexible shaft is a flat shim that is attached to the flat side of the stiff shaft. Such a design advantageously allows the more or less parallel shafts to be inserted into a human body joint for displacement against cartilage, as for example during arthroscopic surgery. The stiff shaft terminates in a plunger extending at right angles to the stiff shaft, with the tip of the plunger lying, in the rest position, between a forked tip of the flexible shaft. In operation, as the plunger tip is displaced into cartilage, the flexible shaft gradually deflects providing a continuous read out from the strain gauge that is indicative of the relative displacement of the plunger tip as it is displaced into the cartilage. Both shafts are mounted to be enclosed within a retractable hollow cannula extending from the probe body.

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Calgary, Canada

Norman S Schachar