DEVICE AND METHOD OF SPACER AND TRIAL DESIGN DURING JOINT ARTHROPLASTY

• US 20120179069A1
• Filed: 02/27/2012
• Published: 07/12/2012
• Est. Priority Date: 03/29/2006
• Status: Active Grant

• Current Assignee: Orthos Sensing Technologies
• Original Assignee: Orthos Sensing Technologies
• Inventors: AMIROUCHE, FARID
• Granted Patent: US 8,656,790 B2
• Time in Patent Office: Days
• US Class Current: 600/587
• 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 spacer block for gathering data to be used in the balancing of the joint arthroplasty or repair and in the selection of a trial insert which includes a first body piece and a second body piece. A plurality of sensors and a processor are positioned between the first body piece and the second body piece when the pieces are assembled together to form the spacer block. A chim is removably mounted to a top surface of the second body piece, the chim is associated with the plurality of sensors and positioned in relation to the plurality of sensors such that a force exerted on the chim by a weight bearing surface is detected by the plurality of sensors.

Claims

1. A system that gathers information to select a trial insert between a femur and tibia of a knee of a patient, comprising:

a first body piece and a second body piece of a spacer, the first body piece being separate from the second body piece, where the first body piece and the second body piece can be assembled together to form the spacer;

a plurality of sensors positioned between the first body piece and the second body piece when the first body piece and the second body piece are assembled;

a processor positioned between the first body piece and the second body piece when the first and the second body pieces are assembled, the processor coupled with the plurality of sensors; and

a chim removably mounted between a top surface of the second body piece and the femur, the chim associated with the plurality of sensors and positioned in relation to the plurality of sensors such that a force exerted on the chim by the femur is detected by the plurality of sensors., where the chim is configured to mount to the top surface of the second body piece through projections on an underside of the chim and corresponding recesses formed in the top surface of the second body piece.

2. The system of claim 1, where the first body piece comprises a plurality of poles integrally formed with the first body piece and extending relative to the inside of the first body piece, and where the plurality of sensors are disposed on each respective pole in recessed walls in the plurality of poles.

3. The system of claim 2, where the second body piece comprises a plurality of apertures configured to receive the plurality of poles.

4. The system of claim 2, where the plurality of sensors are configured to detect a mechanical motion of a respective pole based on a force exerted on the chim, and where the processor is configured to receive a signal from the sensors and provide a measurement of a magnitude of compression experienced by the plurality of poles.

5. The system of claim 4, further comprising a transmitter disposed between the between the first body piece and the second body piece when they are assembled together, and where the processor is configured to transmit the measurement of the magnitude of compression to a remote computer through the transmitter.

8. The system of claim 2, where the plurality of sensors are configured to detect a mechanical motion of a respective pole based on a force exerted on the chim, and where the processor is configured to receive a signal from the sensors and provide a measurement of a magnitude of bending force experienced by the plurality of poles.

9. The system of claim 8, further comprising a transmitter disposed between the between the first body piece and the second body piece when they are assembled together, and where the processor is configured to transmit the measurement of the magnitude of bending force to a remote computer through the transmitter.

10. The system of claim 1, further comprising a handle mounted to the spacer.

11. The system of claim 10, where the handle is detachably connected to the spacer.

12. The system of claim 10, where the plurality of sensors are configured to detect a mechanical motion of a respective pole based on a force exerted on the chim, and where the processor is configured to receive a signal from the sensors and provide a measurement of the mechanical motion.

13. The system of claim 10, further comprising a transmitter disposed in the handle and coupled to the processor, and where the processor is configured to transmit the measurement of the mechanical motion to a remote computer through the transmitter.

6. The system of clam 2, where the plurality of sensors are configured to detect a mechanical motion of a respective pole based on a force exerted on the chim, and where the processor is configured to receive a signal from the sensors and provide a measurement of a magnitude of tension experienced by the plurality of.

7. The system of claim 6, further comprising a transmitter disposed between the between the first body piece and the second body piece when they are assembled together, and where the processor is configured to transmit the measurement of the magnitude of tension to a remote computer through the transmitter.

14. A method to select a joint trial insert, comprising:

inserting into a weight bearing joint a spacer, where the weight bearing joint includes a first bearing surface and a second bearing surface and where the spacer comprises;

a first body piece and a second body piece, the first body piece being separate from the second body piece, where the first body piece and the second body piece can be assembled together to form the spacer, the first body piece comprising a plurality of poles integrally formed with the first body piece and extending relative to an 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 processor positioned between the first body piece and the second body piece when the first and the second body pieces are assembled, the processor coupled with the plurality of sensors; and

a chim removably mountable on a top surface of the second body piece, the chim associated with the plurality of sensors and positioned in relation to the plurality of sensors such that a force exerted on the chim by the weight bearing joint is detected by the plurality of sensors, where the chim is configured to mount to the top surface of the second body piece through projections on an underside of the chim and corresponding recesses formed in the top surface of the second body piece;

manipulating the weight bearing joint so a force is exerted on the chim by the weight bearing joint;

detecting data representing a mechanical motion of each respective pole in the plurality of poles at an onset of the force imposed on the chim, where the detected data provides a measurement of a magnitude of the force exerted on a surface of the first body piece or the second body piece;

transmitting the data to a remote computer.

15. The method of claim 14, further comprising analyzing the data with the remote computer to determine whether to mount a thicker or thinner chim on the spacer.

16. 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 of the first body piece, the first body piece comprising a plurality of poles formed with the first body piece and extending relative to an inside surface of the first body piece;

a plurality of sensors disposed on each respective pole;

a second body piece configured to receive the plurality of poles of the first body piece such that the first body piece and the second body piece mate together and move relative to one another, 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;

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

a chim removably mounted between an outside surface of the second body piece and a structure of a weight bearing joint, the plurality of poles disposed about and aligned with the chim, where the chim is configured to mount to an exterior surface of the second body piece through projections on an underside of the chim and corresponding recesses formed in the exterior surface of the second body piece;

where the plurality of sensors on 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 chim of the first body piece and wherein the processor is configured to receive a signal from the sensors and provide a measurement and value of the magnitude of and location of the force; and

where the processor generates a data modeling the mechanical motion of the plurality of poles.

17. The system of claim 16, where the recesses formed in the exterior surface of the second body piece align with the plurality of poles.

18. The system of claim 16, where the processor transmits a portion of the modeled data through a wired medium.

19. The system of claim 16, where the processor transmits a portion of the modeled data through a wireless medium.

20. The system of claim 16 further comprising a handle that is formed with the first body piece.

21. The system of claim 16 further comprising a handle that is formed with the second body piece.