Measurement device for the muscular-skeletal system having alignment features

• US 10,004,449 B2
• Filed: 09/28/2012
• Issued: 06/26/2018
• Est. Priority Date: 02/27/2012
• Status: Active Grant

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: OrthoSensor, Inc (Stryker Corporation)
• Inventors: Stein, Marc, Carrasco, Gabriel
• Primary Examiner(s): CERIONI, DANIEL LEE
• Application Number:
  US13/631,680
• Publication Number:
  US 20130226035A1
• Time in Patent Office: 2,097 Days
• Field of Search: 33511, 33512, 600587, 600595
• CPC Class Codes: A61B 2562/0252 Load cells
• CPC Class Codes: A61B 5/076 Permanent implantations telemetry using implanted circuitry A61B5/0031; implanted stimulators for therapy A61N1/3605, A61N1/362, A61N1/372
• CPC Class Codes: A61B 5/1036 Measuring load distribution, e.g. podologic studies
• 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 5/4585 Evaluating the knee
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61B 5/6878 Bone
• CPC Class Codes: A61B 5/7225 Details of analog processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation A61B5/30, A61B5/316 take precedence; transformers for specific applications H01F38/00; amplifiers H03F

Abstract

A measurement device suitable to measure a load applied by the muscular-skeletal system is disclosed. The measurement device can be a prosthetic component having an articular surface for measuring parameters of a joint in extension or flexion. A first and second support structure forms an enclosure having load-bearing surfaces. The first support structure includes at least one alignment feature extending from a surface. The second support structure includes a corresponding opening for receiving the alignment feature. The first and second support structures include a peripheral channel and corresponding flange to support sealing of the enclosure. Interior to the enclosure is the measurement system. The alignment feature couples through and aligns a first load plate, a sensor array, and a second load plate to surfaces of the first and second support structures. The sensor array is coupled to electronic circuitry in the enclosure via a unitary circuit board.

Claims

1. A measurement device configured to measure a force, pressure, or load applied by a musculoskeletal system comprising:

a first support structure having a first surface;

a unitary circuit board wherein electronic circuitry coupled to the unitary circuit board is configured to control a measurement process and to transmit measurement data;

a second support structure having a surface wherein the first and second support structures couple together to form a housing;

a first load plate having a first major surface and a second major surface wherein the first major surface of the first load plate couples to an interior surface of the second support structure;

a second load plate having a first major surface and a second major surface wherein the first major surface of the second load plate couples to an interior surface of the first support structure;

a plurality of sensors coupled between the second major surface of the second load plate and the second major surface of the first load plate such that musculoskeletal loading applied to the first surface of the first support structure compresses at least one of the plurality of sensors and wherein the reference sensor remains unloaded when the at least one of the plurality of sensors is compressed by musculoskeletal loading.

2. The measurement device of claim 1 wherein the plurality of sensors comprises an integrated sensor array and wherein a load pad is formed on an electrode of a sensor of the integrated sensor array, and wherein the load pad comprises a metal.

3. The measurement device of claim 2 wherein the load pad comprises a copper or a copper alloy.

4. The measurement device of claim 2 wherein metal of the load pad is plated onto the electrode of the sensor of the sensor array.

5. The measurement device of claim 2 wherein the reference sensor couples to the electronic circuitry, wherein the integrated sensor array includes the reference sensor, and wherein the reference sensor is placed within the housing but outside the first load plate or the second load plate such that the reference sensor does not get compressed when the measurement device is loaded by the musculoskeletal system.

6. The measurement device of claim 1 wherein a plurality of alignment features extend from the interior surface of the second support structure and couple through openings in the first load plate.

7. The measurement device of claim 6 wherein the plurality of alignment features couple through openings in the first support structure and wherein the plurality of alignment features support movement of the first load plate under the musculoskeletal loading.

8. The measurement device of claim 1 wherein a flexible interconnect couples the first plurality of sensors to the electronic circuitry.

9. The measurement device of claim 1 wherein the reference sensor is circular.

11. The measurement device according to claim 1 wherein the first support structure has a peripheral flange, wherein the second support structure has a peripheral channel, and wherein the peripheral flange of the first support structure mates with the peripheral channel of the second support structure to form a seal when the first support structure is coupled to the second support structure.

12. The measurement device of claim 11 wherein the peripheral channel is configured to hold an adhesive.

13. The measurement device of claim 1 wherein the reference sensor is used in a process of testing.

14. The measurement device of claim 1 wherein the reference sensor is one of a piezo-resistive sensor, a mems sensor, a strain gauge, a polymer sensor, or a capacitor.

15. The measurement device of claim 6 wherein the plurality of alignment features of the second support structure are configured to couple through openings in the sensor array and openings in the second load plate.

16. The measurement device of claim 1 wherein the reference sensor is configured to be used for calibration.

17. The measurement device of claim 1 further including a remote system configured to receive measurement data from the measurement device wherein the remote system includes a computer and a display.

18. The measurement device of claim 1 wherein the measurement device is a prosthetic component.

19. The measurement device of claim 8 wherein the first flexible interconnect is shielded.

20. The measurement device of claim 19 wherein the first plurality of sensors is integrated in the flexible interconnect and wherein the first plurality of sensors are shielded.

10. The measurement device of 1 wherein each sensor of the first plurality of sensors are identical and wherein the reference sensor is identical to the first plurality of sensors.