Muscular-skeletal force, pressure, and load measurement system and method

• US 8,696,756 B2
• Filed: 02/27/2012
• Issued: 04/15/2014
• Est. Priority Date: 06/29/2010
• Status: Active Grant

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: OrthoSensor, Inc (Stryker Corporation)
• Inventors: Stein, Marc, Chase, Andrew U.
• Primary Examiner(s): THOMPSON, JEWEL VERGIE
• Application Number:
  US13/406,500
• Publication Number:
  US 20120157885A1
• Time in Patent Office: 778 Days
• Field of Search: 623/20.32, 606/102, 606/90
• US Class Current: 623/20.32
• CPC Class Codes: A61B 5/4509 Bone density determination
• CPC Class Codes: A61B 5/4528 Joints A61B5/4533, A61B5/4538 take precedence
• CPC Class Codes: A61B 5/6846 specially adapted to be brought in contact with an internal body part, i.e. invasive

Abstract

A measurement system for measuring a parameter of the muscular-skeletal system is disclosed. The measurement system comprises a capacitor, a signal generator, a digital counter, counter register, a digital clock, a digital timer, and a data register. The sensor of the measurement system is the capacitor. The measurement system generates a repeating signal having a measurement cycle that corresponds to the capacitance of the capacitor. The capacitor comprises more than one capacitor mechanically in series. Electrically, the capacitor comprises more than one capacitor in parallel. In one embodiment, the capacitor includes a dielectric layer comprising polyimide. A force, pressure, or load is applied to the capacitor that elastically compresses the device.

Claims

1. A force, pressure, or load measurement system for the muscular-skeletal system comprising:

a prosthetic component;

a capacitor coupled to the prosthetic component where the capacitor is configured to elastically compress when a force, pressure, or load is applied by the muscular-skeletal system.

2. The system of claim 1 further including:

a tibial prosthetic component;

an insert prosthetic component; and

a femoral prosthetic component where at least one of the tibial prosthetic component, insert prosthetic component, or femoral prosthetic component includes the capacitor.

3. The system of claim 1 further including electronic circuitry coupled to the capacitor configured to generate a repeating signal corresponding to a capacitance of the capacitor.

4. The system of claim 3 where the capacitor is formed within an interconnect.

5. The system of claim 4 where the interconnect couples to the electronic circuitry.

6. The system of claim 4 where the dielectric of the capacitor comprises one of a polymer, polyimide, a polyester, an aramid, silicon, glass, or composite material.

7. The system of claim 4 further including a ground shield.

8. A knee insert measurement system comprising:

an articular surface;

a load bearing surface; and

a capacitor coupled between the articular surface and the load bearing surface configured to receive a force, pressure, or load.

9. The insert of claim 8 further including electronic circuitry coupled to the capacitor configured to generate a repeating signal corresponding to a capacitance of the capacitor where the capacitor is elastically compressible.

10. The insert of claim 9 where the electronic circuitry is housed in the insert.

11. The insert of claim 10 where the capacitor is formed in an interconnect.

12. The insert of claim 11 where the interconnect couples the capacitor to the electronic circuitry.

13. The insert of claim 12 further including a ground shield.

14. The insert of claim 13 where the ground shield comprises a conductive region of the capacitor.

15. The insert of claim 14 where the capacitor comprises more than one capacitor coupled mechanically in series.

16. The insert of claim 15 where the capacitor comprises more than one capacitor coupled electrically in parallel.

17. The insert of claim 16 where the dielectric of the capacitor comprises one of a polymer, polyimide, a polyester, an aramid, silicon, glass, or composite material.

18. A medical device, tool, or equipment for measuring a force, pressure, or load comprising:

a capacitor;

electronic circuitry coupled to the capacitor configured to generate a repeating signal corresponding to a capacitance of the capacitor where the capacitor is elastically compressible and where the device, tool, or equipment is configured to couple the force, pressure, or load to the capacitor.

19. The medical device, tool, or equipment of claim 18 where the capacitor is formed in an interconnect.

20. The medical device, tool, or equipment of claim 18 where the capacitor includes a ground shield.