Integrated position and parameter sensing for the muscular-skeletal system

• US 9,301,720 B2
• Filed: 06/29/2010
• Issued: 04/05/2016
• Est. Priority Date: 06/30/2009
• Status: Active Grant

• Current Assignee: Howmedica Osteonics Corp. (Stryker Corporation)
• Original Assignee: OrthoSensor, Inc (Stryker Corporation)
• Inventors: Stein, Marc
• Primary Examiner(s): Nghiem, Michael
• Assistant Examiner(s): Satanovsky, Alexander
• Application Number:
  US12/825,834
• Publication Number:
  US 20100332152A1
• Time in Patent Office: 2,107 Days
• Field of Search: 702/41, 735/81, 600/437, 600/587
• US Class Current: 1/1
• 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
• CPC Class Codes: A61B 5/6878 Bone
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives
• CPC Class Codes: A61B 8/15 Transmission-tomography

Abstract

A measurement system for capturing a transit time, phase, or frequency of energy waves propagating through a propagation medium is disclosed. The measurement system comprises a sensing module (200) and an insert dock (202). The sensing module (200) includes a load sensing platform (121), an accelerometer (122), and sensing assemblies (123). In one embodiment, a force or load applied by the muscular-skeletal system is measured. The force or load is applied to the sensing assembly (123). The accelerometer (122) generates motion data. The motion data includes acceleration data. The force or load measured by sensing assembly (123) in combination with the motion data captured by the accelerometer (122) is used to calculate a total force or load. A second accelerometer can be used to provide reference position information. The sensing assemblies (123) comprise a transducer (304), an elastic or compressible propagation structure (305), and a second transducer (314).

Claims

1. A sensing module configured to obtain force measurement comprising:

a load bearing structure configured to be coupled to a muscular-skeletal system;

a sensing assembly coupled to the load bearing structure where the sensing assembly is configured to apply a spring force to the load bearing structure, where the sensing module is configured to be inserted into an implantable orthopedic prosthetic, where the sensing assembly measures force data, where the force data is directly related to the force applied to the sensing assembly by the load bearing structure and where a processor can use the force data to determine the location of the force on the load bearing structure; and

at least one accelerometer, where the at least one accelerometer measures motion data, where a force measurement includes the force data and the motion data.

2. The sensing module of claim 1 where the spring force is provided by way of spring retainer, disc spring, and spring post.

3. The sensing module of claim 2 where the sensing assembly comprises a printed circuit board coupled to a plurality of sensing assemblages.

4. The sensing module of claim 3 where the load bearing structure comprises a steel plate.

5. The sensing module of claim 1 where the accelerometer acquires motion data in a vector quantity.

6. The sensing module of claim 1 where the accelerometer measures a direction and magnitude of acceleration.

7. The sensing module of claim 1 further including a second accelerometer coupled to the muscular-skeletal system to measure acceleration and establish a reference point.

8. The sensing module of claim 1 where the sensing assembly measures a transit time, frequency, or phase of an acoustic signal through a medium and where a change in force applied by the muscular-skeletal results in a change in length of the medium.

9. The sensing module according to claim 1 where prior to a load on the load bearing structure the sensing module is at an original position, where the spring force is used to return the sensing module to the original position when a load is applied to the load bearing structure.

10. A sensing module, comprising:

a load sensing platform configured to receive loading from a portion of an orthopedic system, where the load sensing platform comprises a load bearing structure coupled to a lower printed circuit board (PCB) by way of spring retainer, disc spring, and spring post, where the load sensing platform applies a spring force between a sensing assembly and the portion of the orthopedic system, where the sensing assembly is configured to measure a force and the location of the force on the load bearing structure; and

an accelerometer to produce motion data comprising acceleration data, where the sensing module is configured to be in an implantable orthopedic prosthetic.

11. The sensing module according to claim 10 where prior to a load on the load bearing structure the sensing module is at an original position, where the spring force is used to return the sensing module to the original position when a load is applied to the load bearing structure.

12. The module of claim 10 where the sensing assembly comprises a compressible propagation structure, where the length of the propagation structure corresponds to an applied force thereto, and where the length of the propagation structure is measured.

13. The module of claim 10, further including a second accelerometer, where the first accelerometer is on a first bone to provide first acceleration data, and the second accelerometer is on a second bone to provide second acceleration data, together used as a vector sum to determine effective motion.

14. The module of claim 10, where the sensing assembly comprises an elastic or compressible propagation structure between a first transducer and a second transducer.

15. The module of claim 10, where the load bearing structure comprises a steel plate.

16. The module of claim 10, where the accelerometer includes single-axis and multi-axis structures to detect magnitude and direction of the acceleration.

17. The module of claim 10, where the sensing assembly is positioned, engaged, attached, or affixed to load bearing contact surfaces having mechanical supports to provide proper balancing of load bearing contact surfaces.

18. The module of claim 10, further comprising a transceiver to transmit a level and a direction of the applied force to a receiving station.

19. The module of claim 10, where the processor is a state machine, pre-programmed logic, electronic circuitry, or a micro-controller.