Force monitoring system

• US 8,141,437 B2
• Filed: 03/29/2006
• Issued: 03/27/2012
• Est. Priority Date: 03/29/2006
• Status: Expired due to Fees

• Current Assignee: Orthos Sensing Technologies
• Original Assignee: Orthos Sensing Technologies
• Inventors: Amirouche, Farid, Lopez Espina, Carlos G.
• Primary Examiner(s): Caputo, Lisa
• Assistant Examiner(s): DUNLAP, JONATHAN M
• Application Number:
  US11/393,098
• Publication Number:
  US 20070234819A1
• Time in Patent Office: 2,190 Days
• Field of Search: 737/81, 738/620.41, 600/595, 606/88, 623/17.15, 623/18.11, 623 2014- 2036
• US Class Current: 73/862.041
• CPC Class Codes: A61F 2/389 Tibial components A61F2/3868 takes precedence
• CPC Class Codes: A61F 2/4657 Measuring instruments used for implanting artificial joints for surgical instruments A61B90/06
• CPC Class Codes: A61F 2/4684 Trial or dummy prostheses
• CPC Class Codes: A61F 2002/30668 Means for transferring electromagnetic energy to implants
• CPC Class Codes: A61F 2002/4666 for measuring force, pressure or mechanical tension
• CPC Class Codes: G01L 1/2225 the direction being perpendicular to the central axis
• CPC Class Codes: G01L 5/0019 by using strain gages, piezoelectric, piezo-resistive or other ohmic-resistance based sensors

Abstract

A system monitors dynamic forces between bearing surfaces. Based on sensed data, the system may model the forces on the bearing surfaces, analyze these forces, store data relating to these forces, and/or transmit data to an external data gathering device. The system includes a first body piece and a second body piece which mate together. The first and second body pieces comprise bearing surfaces that contact a material that may exert a force. A protrusion, such as a pole, post, or beam, extends from first body piece'"'"'s bearing surface. At least one sensor is disposed on a pole. The at least one sensor detects a mechanical motion of the pole resulting from a force imposed on the body pieces, and generates data indicative of this force. A computer communicates with the at least one sensor and processes the sensed and/or modeled data.

Claims

1. A system that monitors forces between a first bearing surface and a second mating or conforming bearing surface, comprising:

a first body piece adapted to contact the first bearing surface on an outside surface of the first body piece, the first body piece comprising a plurality of poles integrally formed with the first body piece and extending relative to the inside surface of the first body piece;

a plurality of sensors disposed on each respective pole in recessed walls in the plurality of poles;

a second body piece adapted to contact the second bearing surface on an outside surface of the second body piece, the second body piece having a first recess configured to receive a first condoyle of an artificial knee insert and a second recess configured to receive a second condoyle of the artificial knee insert, the second body piece configured to receive the plurality poles of the first body piece such that the first body piece and second body piece mate together and move relative to one another, a first plurality of poles symmetrically disposed about and aligned with the first recess and a second plurality of poles symmetrically about and aligned with the second recess, where an inside surface of the second body piece contacts the plurality of poles without detectible load transfer when no force is applied to the mated first and second body pieces; and

a computer in communication with the plurality of sensors in each respective pole in the plurality of poles, the computer disposed in a recessed cavity between the first body piece and the second body piece when they mate together;

where the plurality of sensors in each respective pole are configured to detect a mechanical motion of a respective pole at an onset of a dynamic force exerted on an external surface of the first or the second body piece and wherein the computer is configured to receive a signal from the sensors and provide a measurement and value of the magnitude of the force and location of the force.

2. The system of claim 1, further comprising conditioning logic in communication with the plurality of sensors and the computer.

3. The system of claim 2, where the conditioning logic is flexibly coupled to the at least one sensor.

4. The system of claim 1, where the computer provides measurement of the force exerted at a contact point between the inside surface of the second body piece and the plurality of poles in real-time.

5. The system of claim 4, where the plurality of sensors transmit a voltage signal in response to the mechanical motion of the plurality of poles.

6. The system of claim 5, where the signal conditioning logic converts the voltage signal to an electrical signal related to an amount of deformation in a respective pole in the pole plurality of poles.

7. The system of claim 6, where the signal conditioning logic substantially removes a continuous noise from the electrical signal.

8. The system of claim 6, where the signal conditioning logic amplifies the electrical signal.

9. The system of claim 8, where the computer is configured to transmit at least a portion of the amplified signal through a wired medium.

10. The system of claim 8, where the computer is configured to transmit at least a portion of the amplified signal through a wireless medium.

11. The system of claim 8, where the computer generates a data modeling the mechanical motion of the plurality of poles.

12. The system of claim 11, where a memory stores the modeled data.

13. The system of claim 12, where the computer transmits at least a portion of the modeled data through a wired medium.

14. The system of claim 12, where the computer transmits at least a portion of the modeled data through a wireless medium.

15. The system of claim 14, where the computer transmits at least a portion of the modeled data in real-time.

16. The system of claim 1 wherein the system includes a second condyle recess adapted to engage a second condyle in the first bearing surface at a second point of contact.

17. A method of monitoring a force between bearing surfaces, comprising:

embedding inside a weight bearing joint a force monitoring unit, wherein the weight bearing joint includes a first bearing surface and a second bearing surface and wherein the force monitoring unit comprises;

a first body piece adapted to contact the first bearing surface on an outside surface of the first body piece, the first body piece comprising a plurality of poles integrally formed with the first body piece and extending relative to the inside surface of the first body piece;

a plurality of sensors disposed on each respective pole in the plurality of poles;

a second body piece adapted to contact the second bearing surface on an outside surface of the second body piece, the second body piece having at least one recess configured to receive a condoyle of an artificial knee insert, the second body piece configured to receive the plurality of poles of the first body piece such that the first body piece and second body piece mate together and move relative to one another, a first plurality of poles symmetrically disposed about and aligned with the first recess and a second plurality of poles symmetrically about and aligned with the second recess, where an inside surface of the second body piece contacts the plurality of poles without detectible load transfer when no force is applied to the mated first and second body pieces;

detecting data representing a mechanical motion of each respective pole in the plurality of poles at an onset of a dynamic force imposed on the monitoring device by the weight bearing joint wherein the detected data provides a measurement and value of the magnitude of the force exerted on a surface of first body piece or the second body piece;

conditioning the detected data;

processing the conditioned data to determine the location the force is exerted; and

transmitting the processed data to a data gathering device.

18. The method of claim 17, where the act of detecting a mechanical motion of the plurality of poles comprises affixing a plurality of sensors to each respective pole in the plurality of poles.

19. The method of claim 18, where the act of detecting a mechanical motion of the plurality of poles further comprises generating a voltage signal representative of a sensed mechanical motion.

20. The method of claim 19, where the act of conditioning the detected data comprises converting the voltage signal to a data representative of an amount of force exerted by the weight bearing surface.

21. The system of claim 20, where the act of processing the conditioned data comprises performing a statistical analysis on the data representative of the amount of force exerted by the weight bearing surface.

22. The method of claim 21, where the act of transmitting the processed data comprises establishing a wireless connection with a data gathering device.

23. The method of claim 22, where the act of transmitting the processed data further comprises transmitting the processed data in real-time.