Cycle and load measurement device

• US 8,388,553 B2
• Filed: 11/04/2005
• Issued: 03/05/2013
• Est. Priority Date: 11/04/2004
• Status: Active Grant

• Current Assignee: Smith & Nephew Incorporated (Smith & Nephew PLC)
• Original Assignee: Smith & Nephew Incorporated (Smith & Nephew PLC)
• Inventors: Janna, Sied W., James, Anthony H.
• Primary Examiner(s): TOWA, RENE T
• Application Number:
  US11/718,588
• Publication Number:
  US 20080208516A1
• Time in Patent Office: 2,678 Days
• Field of Search: 600/587, 600/595, 623/16.11, 623/914
• US Class Current: 600/587
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• 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 5/1118 Determining activity level
• CPC Class Codes: A61B 5/4504 Bones A61B5/4547 takes precedence
• CPC Class Codes: G01P 15/0891 with indication of predetermined acceleration values G01P15/135 takes precedence

Abstract

The present application relates to a sensing system for an medical device, the sensing system having at least one sensor for measuring movement of the medical device and a recording device for storing movement data from the at least one sensor. The application also relates to a method for evaluating a patient'"'"'s compliance with a healing regimen, the patient provided with a medical device, the method having the steps of a) collecting movement data relating to movement of a sensing system affixed within, to, or near the medical device; b) retrieving the movement data from the sensing system; and c) analyzing the movement data and comparing the movement data to standard movement data to evaluate the patient'"'"'s compliance with the healing regimen.

Claims

1. A method for evaluating a patient'"'"'s compliance with a bone healing regimen, the patient provided with a medical device, the method comprising:

collecting movement data relating to movement of a sensing system affixed within, to, or near the medical device;

retrieving the movement data from the sensing system;

analyzing the movement data to determine cycle counts for one or more acceleration levels for each of a plurality of time periods; and

evaluating the patient'"'"'s compliance with the bone healing regimen by comparing the cycle counts to a standard cycle distribution comprising a plurality of standard cycle counts that have predetermined values that indicate a different number of cycles for at least some of the plurality of time periods.

2. The method of claim 1, in which the sensing system comprises at least a first discrete accelerometer and a second discrete accelerometer, and the first discrete accelerometer and the second discrete accelerometer have different acceleration setpoints, and

in which the sensing system comprises a recording device for storing movement data from the first discrete accelerometer and the second discrete accelerometer.

3. The method of claim 2, in which at least one of the acceleration setpoints is a maximum acceleration setpoint defined such that a cycle is detected if a measured acceleration is below the maximum setpoint.

4. The method of claim 2, in which at least one of the acceleration setpoints is a minimum acceleration setpoint.

5. The method of claim 2, in which the recording device stores movement data from the first discrete accelerometer when the first discrete accelerometer detects an acceleration rate that exceeds one of the acceleration setpoints.

6. The method of claim 5, in which the acceleration setpoint of the first discrete accelerometer or the acceleration setpoint of the second discrete accelerometer is from 0.25 to 100 m/s².

7. The method of claim 1, in which the medical device is an intramedullary nail, a bone plate, a bone screw, an external fixation device, a joint product, a trauma product, a spine product, or an interference screw.

8. The method of claim 1, in which the sensing system is located within an intramedullary nail cap.

9. The method of claim 1, wherein analyzing the movement data to identify cycle counts for one or more acceleration levels comprises analyzing the movement data to identify cycle counts for a plurality of different acceleration levels.

10. The method of claim 1, wherein evaluating the patient'"'"'s compliance with the bone healing regimen by comparing the cycle counts to the standard cycle distribution comprises comparing the cycle counts to a standard cycle distribution indicating a number of cycles at each of a plurality of load levels.

11. The method of claim 1, wherein the standard cycle distribution corresponds to the bone healing regimen and indicates, for the plurality of time periods, numbers of cycles that increase with time.

12. The method of claim 1, wherein the bone healing regimen is a post-surgical bone healing regimen.

13. The method of claim 1, wherein evaluating the patient'"'"'s compliance with the bone healing regimen by comparing the cycle counts to the standard cycle distribution comprises determining whether the patient'"'"'s activity level is compliant.

14. The method of claim 1, wherein collecting movement data relating to movement of a sensing system affixed within, to, or near the medical device comprises collecting movement data relating to movement of a sensing system affixed within, to, or near the medical device, the sensing system comprising a continuous accelerometer configured to detect movement data at a fixed cycle interval.

15. The method of claim 1, wherein collecting movement data relating to movement of a sensing system affixed within, to, or near the medical device comprises collecting movement data relating to movement of a sensing system affixed within, to, or near the medical device, the sensing system comprising at least a first discrete accelerometer and a second discrete accelerometer, the first discrete accelerometer and the second discrete accelerometer having different acceleration setpoints;

and

wherein analyzing the movement data to determine cycle counts for one or more acceleration levels comprises analyzing the movement data to determine cycle counts for a plurality of acceleration levels, each of the plurality of acceleration levels corresponding to one of the acceleration setpoints.

16. The method of claim 1, wherein the medical device is externally affixed to the patient'"'"'s body.

17. The method of claim 1, wherein collecting movement data relating to movement of a sensing system affixed within, to, or near the medical device comprises applying one or more noise filters to reduce noise in acceleration data measured by the sensing system.

18. The method of claim 1, further comprising depicting the detected cycle counts and the standard cycle counts of the standard cycle distribution in a graph.

19. The method of claim 1, wherein the sensing system stores patient data comprising one or more of patient height, patient weight, and patient surgical intervention information.

20. The method of claim 1, wherein the sensing system is located within a washer configured to be attached to a bone or to a bone plate.

21. The method of claim 1, wherein the sensing system comprises a plurality of sensors having different setpoints, the different setpoints varying by substantially equal increments.

22. The method of claim 1, wherein the medical device is an orthopaedic support or immobilization device.

23. The method of claim 1, wherein the cycle counts define a patient curve and the predetermined standard cycle counts define a standard curve,

wherein comparing the cycle counts to the standard cycle distribution comprises comparing the patient curve with the standard curve.

24. The method of claim 23, wherein evaluating the patient'"'"'s compliance with the bone healing regimen comprises assessing a degree to which the patient curve tracks the standard curve.

25. A method for evaluating a patient'"'"'s compliance with a bone healing regimen, the patient provided with a medical device, the method comprising:

collecting movement data relating to movement of a sensing system affixed within, to, or near the medical device, the sensing system comprising at least a first discrete accelerometer for measuring movement of the medical device and a second discrete accelerometer for measuring movement of the medical device, the first discrete accelerometer and the second discrete accelerometer having different acceleration setpoints;

retrieving the movement data from the sensing system;

analyzing the movement data to determine, for each of a plurality of time periods, detected cycle counts for movements corresponding to the different acceleration setpoints; and

evaluating the patient'"'"'s compliance with the bone healing regimen by comparing the detected cycle counts for the plurality of time periods to a standard cycle distribution indicating a predetermined set of standard cycle counts corresponding to the plurality of time periods, the standard cycle distribution indicating different standard cycle counts for at least some of the plurality of time periods,

in which the sensing system comprises a recording device for storing movement data from the first discrete accelerometer and the second discrete accelerometer, and the recording device stores movement data from the first discrete accelerometer and the second discrete accelerometer.

26. The method of claim 25, in which at least one of the acceleration setpoints is from 0.25 to 100 m/s².

27. The method of claim 25, in which the medical device is an intramedullary nail, a bone plate, a bone screw, an external fixation device, a joint product, a trauma product, a spine product, or an interference screw.

28. The method of claim 25, in which at least one of the acceleration setpoints is a maximum acceleration setpoint defined such that a cycle is detected if a measured acceleration is below the maximum setpoint.

29. The method of claim 25, in which at least one of the acceleration setpoints is a minimum acceleration setpoint.

30. The method of claim 25, in which the sensing system is located within an intramedullary nail cap.

31. The method of claim 25, wherein the standard cycle counts indicate preset levels of activity that comply with the post-surgical bone healing regimen at corresponding time periods during the post-surgical bone healing regimen.

32. A method for evaluating a patient'"'"'s compliance with a bone healing regimen, the patient provided with a medical device, the method comprising:

collecting movement data relating to movement of a sensing system affixed within, to, or near the medical device;

retrieving the movement data from the sensing system;

analyzing the movement data to determine cycle counts for a plurality of different acceleration levels; and

evaluating the patient'"'"'s compliance with the bone healing regimen by comparing the cycle counts to a standard cycle distribution corresponding to the bone healing regimen, wherein the standard cycle distribution defines a predetermined curve indicating expected activity levels at different time periods during the bone healing regimen, and the standard cycle distribution indicates a different number of cycles for each of a plurality of time periods.

33. The method of claim 32, wherein the standard cycle counts indicated by the standard cycle distribution include standard cycle counts for each of multiple consecutive days.

34. The method of claim 32, wherein the plurality of time periods include three or more consecutive days, and the standard cycle distribution indicates different standard cycle counts for each of the three or more consecutive days.

35. A method for evaluating a patient'"'"'s compliance with a post-surgical bone healing regimen, the patient having an implanted intramedullary nail, the method comprising:

collecting movement data relating to movement of a sensing system located within the intramedullary nail or an intramedullary nail cap coupled to the intramedullary nail, the sensing system comprising at least a first discrete accelerometer for measuring movement of the patient and a second discrete accelerometer for measuring movement of the patient, the first discrete accelerometer and the second discrete accelerometer having different acceleration setpoints;

analyzing the movement data to determine, for each of a plurality of time periods, detected cycle counts for movements corresponding to the different acceleration setpoints; and

evaluating the patient'"'"'s compliance with the post-surgical bone healing regimen by comparing the detected cycle counts for each of the plurality of time periods with a standard cycle distribution comprising a collection of predetermined standard cycle counts that represent preset levels of activity that comply with the post-surgical bone healing regimen at corresponding time periods during the post-surgical bone healing regimen, the predetermined standard cycle counts having different cycle count values for at least some of the plurality of time periods.

36. The method of claim 35, wherein the standard cycle distribution defines a predetermined standard curve that spans the plurality of time periods and indicates predetermined trends in the levels of activity that comply with the post-surgical bone healing regimen during the post-surgical bone healing regimen.

37. The method of claim 36, wherein the cycle counts over the plurality of time periods define a patient curve that spans the plurality of time periods,

wherein comparing the cycle counts for the plurality of time periods with the standard cycle distribution comprises comparing the patient curve for the plurality of time periods with portions of the predetermined standard curve corresponding to the plurality of time periods.

38. The method of claim 37, wherein evaluating the patient'"'"'s compliance with the bone healing regimen comprises assessing a degree to which the patient curve tracks the predetermined standard curve.

39. The method of claim 36, wherein the standard cycle distribution defines a patient-independent standard trend curve that indicates expected activity levels during the healing regimen.

40. The method of claim 39, wherein the patient-independent standard trend curve indicates expected activity levels over the course of the entire post-surgical bone healing regimen.

41. The method of claim 35, wherein the plurality of time periods include three or more consecutive days, and the standard cycle distribution includes different standard daily cycle counts for each of the three or more consecutive days.