Contact sensors and methods for making same

Abstract

Disclosed herein are novel contact sensors. The contact sensors disclosed herein include a conductive composite material formed of a polymer and a conductive filler. In one particular aspect, the composite materials can include less than about 10 wt % conductive filler. Thus, the composite material of the contact sensors can have physical characteristics essentially identical to the polymer, while being electrically conductive with the electrical resistance proportional to the load on the sensor. The sensors can provide real time dynamic contact information for joint members under conditions expected during use.

We claim: 
     
         1 - 18 . (canceled) 
     
     
         19 . A contact sensor system, comprising:
 a data acquisition terminal; and   a surgical insert defining a contact surface configured to receive a load applied by an electrically conductive joint element, the contact surface having selected spaced conductive portions, wherein the selected spaced conductive portions define an array of sensing points that are in communication with the data acquisition terminal, wherein the surgical insert is configured for insertion therein a selected joint within the body of a subject, and wherein the conductive portions of the contact surface, during application of the load, comprises means for producing an output signal indicative of the change in electrical resistance experienced across the contact surface at at least one sensing points,   wherein the output signal produced by each sensing point corresponds to variations in the load between the electrically conductive joint element and the contact surface.   
     
     
         20 . The contact sensor of  claim 19 , wherein the surgical insert can be used in one of a knee joint, a hip joint, a shoulder joint, an ankle joint, and a spinal joint. 
     
     
         21 . The contact sensor of  claim 19 , wherein the surgical insert comprises one of a tibial insert, a femoral insert, a patellar insert, an acetabular insert, a scapular insert, a humeral insert, a talar insert, and a vertebral insert. 
     
     
         22 . The contact sensor of  claim 21 , wherein the contact surface extends therein the surgical insert to a depth ranging from about 50 nm to about 1000 nm.