US20060142670A1 - System and method for determining patient follow-up subsequent to an orthopaedic procedure - Google Patents

Abstract

A method of determining patient follow-up subsequent to an orthopaedic procedure includes determining the number of cycles of use of an orthopaedic joint of the patient. If a predetermined threshold is exceeded, communication with an orthopaedic care provider is initiated. A patient monitoring system is also disclosed.

Description

FIELD OF THE DISCLOSURE
• The present disclosure relates generally to systems and methods for use in conjunction with orthopaedic procedures.
BACKGROUND
• Currently, patient follow-up subsequent to an orthopaedic procedure is a function of the time that has elapsed since the procedure. Indeed, follow-up meetings with the orthopaedic care provider (e.g., the surgeon) are typically scheduled for dates in the future which reflect the passage of a given amount of time since the procedure.
SUMMARY
• According to one aspect of the disclosure, a method of determining patient follow-up subsequent to an orthopaedic procedure includes determining the number of cycles of use of an orthopaedic joint of the patient. If a predetermined threshold is exceeded, communication with an orthopaedic care provider is initiated.
• The number of cycles of use of the patient's joint may be determined by (i) determining number of steps taken by the patient, (ii) determining the activity level of the patient, (iii) determining the number of times a predetermined joint flexion angle is achieved, or (iv) determining the number of loading cycles of the joint.
• The communication with the orthopaedic care provider (e.g., a surgeon) is initiated by notifying the patient and/or the orthopaedic care provider. Such communication may be initiated by a phone call, electronic mail message, or other web-based communication. Such a communication may be an automated, device-initiated communication.
• The orthopaedic joint of the patient may be a prosthetic joint. The orthopaedic joint of the patient may have at least one natural orthopaedic component.
• A patient monitoring system includes a joint use measurement device configured to determine the cycles of use of an orthopaedic joint of a patient.
• The joint use measurement device is operable to generate a message if a predetermined threshold is attained.
BRIEF DESCRIPTION OF THE DRAWINGS
• The detailed description particularly refers to the accompanying figures in which:
• FIG. 1 is a diagrammatic view showing a joint use measurement device in the form of a pedometer being utilized to determine the cycles of use of a knee endoprosthesis system;
• FIG. 2 is a diagrammatic view showing a joint use measurement device in the form of a electronic body monitor being utilized to determine the cycles of use of a knee endoprosthesis system;
• FIG. 3 is a diagrammatic view showing a joint use measurement device in the form of an implantable joint cycle counter being utilized to determine the cycles of use of a knee endoprosthesis system; and
• FIG. 4 is a diagrammatic view showing a joint use measurement device in communication with a communication device.
DETAILED DESCRIPTION OF THE DRAWINGS
• The present disclosure relates to a method for determining patient follow-up after an orthopaedic procedure, such as a joint replacement procedure, based on the actual use of the patient's joint. As will be described herein in greater detail, the number of cycles of use of the patient's joint may be determined, for example, by (i) determining number of steps taken by the patient, (ii) determining the activity level of the patient, (iii) determining the number of times a predetermined joint flexion angle is achieved, or (iv) determining the number of loading cycles of the joint. Determination of these parameters may be achieved in a number of different manners. When it is determined that the patient has achieved a level of use in which follow-up is desired, a communication with the orthopaedic care provider (e.g., a surgeon, hospital, nurse, primary care provider, or other individual involved in the care of the patient) is initiated by notifying the patient and/or the orthopaedic care provider. As will be described herein in greater detail, such communication may be achieved in a variety of different manners.
• Referring now toFIG. 1, there is shown one implementation of the concepts of the present disclosure. In this case, a jointuse measurement device10 is utilized to determine the number of cycles of use of a prostheticorthopaedic joint12. In the exemplary arrangement ofFIG. 1, theorthopaedic joint12 is exemplary embodied as aknee endoprosthesis system14 for use in a total knee replacement procedure. Theknee endoprosthesis system14 is implanted on the distal end of thefemur16 and the proximal end of thetibia18. Theendoprosthesis system10 includes a tibial bearing20 that is positioned on the proximaltibial component22. The proximaltibial component22 is affixed to the proximal end of thetibia18. Thetibial bearing20 has a contouredproximal surface24, against which thecondyles26 of the distalfemoral component28 bear. The distalfemoral component28 is affixed to the distal end of thefemur16. Articulation of the joint is at the interface of theproximal surface24 of the tibial bearing20 and thecondyles26 of the distalfemoral component28.
• The actual use of theknee endoprosthesis system14 may be characterized as cycles of use of the system. The cycles of use of thesystem14 may be measured in a variety of methods such as, for example, (i) by determining number of steps taken by the patient, (ii) by determining the activity level of the patient, (iii) by determining the number of times a predetermined joint flexion angle is achieved by thesystem14, or (iv) by determining the number of loading cycles of thesystem14.
• In the exemplary embodiment shown inFIG. 1, the jointuse measurement device10 is embodied as apedometer30. Thepedometer30 is worn by the patient subsequent to the patient's orthopaedic procedure to determine the number of steps taken by the patient. When the output from thepedometer30 indicates that the patient has taken a predetermined number of steps since the patient's orthopaedic procedure (or since the patient's previous meeting with the surgeon), a communication with the orthopaedic surgeon may be initiated. For example, the patient may make an appointment with the surgeon's office via telephone, electronic mail or other web-based communication, conventional mail, etcetera.
• Referring now toFIG. 2, there is shown an arrangement similar toFIG. 1, but showing the jointuse measurement device10 embodied as anelectronic body monitor32. Theelectronic body monitor32 is configured to be worn externally of the patient's body such as, for example, on an armband. Like thepedometer30 ofFIG. 1, theelectronic body monitor32 may be used to determine the number of steps taken by the patient over a given period of time (e.g., since the patient's procedure or since the patient's previous post-surgical meeting with the surgeon). Theelectronic body monitor32 may also execute algorithms for determining and tracking the activity level of the patient. In this way, follow-up may be initiated as a function of steps taken by the patient, activity level of the patient, or both.
• As shown inFIG. 2, theelectronic body monitor32 includes asensor34 that is configured to sense parameters associated with cycles of use of theknee endoprosthesis system14. Thesensor34 may be embodied as a single sensor or as an array of sensors. In one exemplary embodiment, thesensor34 is embodied as a two-axis accelerometer the output from which may be used to determine the number of steps taken by the patient. Theelectronic body monitor32 also includes aprocessor36 electrically coupled to thesensor34, amemory device38, and adata output port40. Theprocessor36 is electrically coupled to thedata output port40 and thememory device38. Theelectronic body monitor32 may also include other devices useful in a computing device such as drivers, registers, buffers, digital signal processors, and the like. Illustratively, theelectronic body monitor32 may be embodied, with or without modification thereto, as any one of the numerous body monitors commercially available from BodyMedia, Incorporated of Pittsburgh, Pa. One such BodyMedia device is commercially sold under the name SenseWare PRO.
• Theprocessor36 andmemory device38 cooperate to determine when follow-up subsequent to an orthopaedic procedure is warranted based on cycles of use of theknee endoprosthesis system14. In particular, thememory device38 has stored therein a plurality of instructions in the form of a software routine which performs such a function. Thememory device38 may be Random Access Memory (hereinafter sometimes RAM), Read Only Memory (hereinafter sometimes ROM), flash or erasable memory such as Erasable Programmable ROM (hereinafter sometimes EPROM) and Electrically Erasable Programmable ROM (hereinafter sometimes EEPROM), and/or other memory devices. Due to the adaptable nature of programming languages, there are many embodiments of a software routine stored in thememory device38 for performing such a function.
• Theelectronic body monitor32 also includes amessage generating device42. Themessage generating device42 is operable to generate visual and/or audible messages for presentation to the patient. For example, when theelectronic body monitor32 determines that the patient has exceeded a predetermined threshold relating to the number of steps taken by the patient (or activity level) since the patient's procedure (or last meeting with the surgeon), an audible and/or visual alert may be generated by themessage generating device42. Themessage generating device42 may be embodied as any type of such device including, for example, an LCD or LED display and/or a tone/sound generator.
• Referring now toFIG. 3, the jointuse measurement device10 includes an implantedsensor50. Thesensor50 may be embodied as a single sensor or as an array of sensors. In the exemplary embodiment ofFIG. 3, the implantedsensor50 includes asignal source52, such as a permanent magnet, that is embedded in the distalfemoral component28, and asensor54, such as a Hall effect switch, embedded in theproximal tibial component22. The associatedelectronics56 are also secured to theproximal tibial component22. Theelectronics56 include, amongst other things, a processor, memory device, power source, modulator, a transmitter, and antenna to facilitate the maintenance of a running count of the number of times theknee endoprosthesis system14 cycles, along with the ability to transmit such a count from within the patient's body. In other words, the jointuse measurement device10 illustrated inFIG. 3 utilizes an implanted sensor to determine the number of occasions in which the components of theknee endoprosthesis system14 are in a predetermined relative position with one another (e.g., the number of occasions in which a predetermined flexion angle is attained), thereby determining cycles of use of thesystem14.
• The stored count information can be transmitted to a device external to the patient's body by use of the transmitter and antenna of the associatedelectronics56. As shown schematically inFIG. 3, anexternal receiver58 anddata interpretation device60 may be used to retrieve information from the implantedelectronics56. Theexternal receiver58 may be embodied as a radio-frequency antenna that is operable to receive the signal from the internal antenna of the implantedelectronics56. Thedata interpretation device60 is electrically coupled to thereceiver58, and may be embodied as a standard computer (e.g., PC) programmed to demodulate the radio-frequency signal received from the internal transmitter and the internal antenna of the implantedelectronics56. Thedata interpretation device60 may also be embodied as a hand-held personal computer, a personal desk assistant, a laptop computer, or any custom-designed data acquisition device. Thedata interpretation device60 may be programmed to perform calculations necessary to convert the received and demodulated signal into the number of cycles recorded by the counter.
• One such implantable system, along with the associated external components, is disclosed in U.S. patent application Ser. No. 10/887,766, entitled “In Vivo Joint Implant Cycle Counter” which is assigned to the assignee of the present application, and which is hereby incorporated by reference.
• Thedata interpretation device60 may have integrated therein, or be coupled to, amessage generating device62. Themessage generating device62 is operable to generate visual and/or audible messages for presentation to the patient. For example, when it is determined from the output of the implantedelectronics56 that the number of occasions in which theknee endoprosthesis system14 has attained a predetermined flexion angle has exceeded a predetermined threshold, an audible and/or visual alert may be generated by themessage generating device62. Themessage generating device62 may be embodied as any type of such device including, for example, a PC display monitor, an LCD or LED display, and/or a tone/sound generator.
• In lieu of the arrangement ofFIG. 3 which includes a magnet and Hall effect switch, other implanted sensor arrangements are also contemplated. For example, a load sensor may be implanted into theknee endoprosthesis system14. In such a system, the cycles of use of thesystem14 could be determined by counting loading cycles of the system. Such a count could be stored, transmitted, and received in a similar manner to as described above in regard to the arrangement ofFIG. 3.
• In another example, the cycles of use of the patient's joint may be determined by measuring the wear of certain components of theknee endoprosthesis system14. For instance, a sensor arrangement may be utilized in which the joint space between thefemoral component28 and thetibial component22 is measured/monitored. It should be appreciated that such a distance may shorten (i.e., reduce) over cycles of the knee endoprosthesis system as a result of wear of thetibial bearing20. As such, the cycles of use of thesystem14 could be determined by measuring and tracking the joint space between thefemoral component28 and thetibial component22. Such data could be stored, transmitted, and received in a similar manner to as described above in regard to the arrangement ofFIG. 3. One such implantable system, along with the associated external components, is disclosed in U.S. patent application Ser. No. 10/888,243, entitled “System and Method for Determining Patient Follow-Up Subsequent to an Orthopaedic Procedure” which is assigned to the assignee of the present application, and which is hereby incorporated by reference.
• Referring now toFIG. 4, there is shown the jointuse measurement device10 being used in conjunction with acommunications device70. Thecommunications device70 may be embodied as hardware and software that is integrated into a personal computer, wireless (e.g., cellular) telephone, PDA, or home automation system. Alternatively, thecommunications device70 may be a discreet hardware/software assembly electrically coupled to a personal computer, wireless (e.g., cellular) telephone, PDA, or home automation system. In either case, thecommunications device70 includes devices useful in a computing device such as microprocessor(s), memory devices, drivers, registers, buffers, digital signal processors, and the like
• Thecommunications device70 may be operated to query the jointuse measurement device10 and then commence an automated, device-initiated communication with the orthopaedic care provider (e.g., the surgeon's office) if a follow-up visit is warranted based on the number of cycles of use of theknee endoprosthesis system14. For example, thecommunications device70 may initiate a telephone call, electronic mail communication, or other web-based communication with an electronic device orsystem72 operated by the surgeon's office.
• It should be appreciated that thecommunications device70 may be configured to accommodate any one or more of the different exemplary embodiments of the jointuse measurement device10. For example, in the case of the electronic body monitor32 ofFIG. 2, thecommunications device70 may be configured to communicate with the body monitor32 via itsdata output port40. Such a communication may be wired or wireless depending on the configuration of theport40. It is contemplated to integrate thecommunications device70 into theelectronic body monitor32.
• Similarly, thecommunications device70 may be configured to communicate withdata interpretation device60 of the arrangement ofFIG. 3 via either a wired or wireless communication link. It should be appreciated that thecommunications device70 may be integrated into the data interpretation device60 (i.e., a single device, such as a PC, may be equipped with the necessary hardware and software to perform both the functions of thedata interpretation device60 and the functions of the communications device70).
• In the case of when the jointuse measurement device10 is embodied as a mechanical device (i.e., non-electrical) such as, for example, certain types of pedometers, data from the mechanical device may be input into thecommunications device70. In such a case, thecommunications device70 may be configured to process such manually entered data, and then, if appropriate, initiate communication with the surgeon in any one or more of the manners described above.
• Although the concepts of the present disclosure have herein been described in regard to a knee prosthesis, it should be appreciated that the concepts described herein could also be applied to other joint endoprosthesis such as endoprosthesis systems for use in the hip, shoulder, wrist, elbow, ankle, along with endoprosthesis systems for use with the digits of the extremities. It should be understood that other configurations of a joint use measurement device (including its sensors) may be utilized to accommodate a given application in a desired joint location.
• Moreover, although the concepts of the present disclosure have herein been exemplary described in regard to an endoprosthesis for use in a total joint replacement, it should be appreciated that the concepts described herein could also be applied to other arrangements. For example, the concepts of the present disclosure could be applied subsequent to a procedure in which the resultant joint includes one or more natural components. Moreover, the concepts of the present disclosure could be applied subsequent to an orthopaedic procedure at anatomical locations other than a joint.
• While the disclosure is susceptible to various modifications and alternative forms, specific exemplary embodiments thereof have been shown by way of example in the drawings and has herein be described in detail. It should be understood, however, that there is no intent to limit the disclosure to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure.
• There are a plurality of advantages of the present disclosure arising from the various features of the apparatus and methods described herein. It will be noted that alternative embodiments of the apparatus and methods of the present disclosure may not include all of the features described yet still benefit from at least some of the advantages of such features. Those of ordinary skill in the art may readily devise their own implementations of an apparatus and method that incorporate one or more of the features of the present disclosure and fall within the spirit and scope of the present disclosure.

Claims (27)

1. A method of determining patient follow-up subsequent to an orthopaedic procedure, the method comprising the steps of:

determining the number of cycles of use of an orthopaedic joint of a patient, and

initiating communication with an orthopaedic care provider in response to the determining step.

2. The method ofclaim 1, wherein the determining step comprises determining the number of cycles of use of the orthopaedic joint and generating an output signal in response thereto, further comprising the step of:

generating a message to the patient in response to generation of the output signal.

3. The method ofclaim 2, wherein the step of generating the message comprises generating an audible message.

4. The method ofclaim 2, wherein the step of generating the message comprises generating a visual message.

5. The method ofclaim 1, wherein the determining step comprises determining the number of steps taken by the patient.

6. The method ofclaim 5, wherein determining the number of steps taken by the patient comprises monitoring output from a pedometer.

7. The method ofclaim 1, wherein the determining step comprises determining the activity level of the patient.

8. The method ofclaim 7, wherein determining the activity level of the patient comprises monitoring output from a sensor external to the body of the patient.

9. The method ofclaim 1, wherein the determining step comprises determining the number of occasions that a predetermined flexion angle is obtained by the orthopaedic joint of the patient.

10. The method ofclaim 1, wherein the determining step comprises determining the number of loading cycles of the orthopaedic joint of the patient.

11. The method ofclaim 1, wherein the determining step comprises monitoring output from a sensor implanted into the body of the patient.

12. The method ofclaim 1, wherein the determining step comprises monitoring output from a sensor external to the body of the patient.

13. The method ofclaim 1, wherein:

the orthopaedic joint of the patient comprises a prosthetic orthopaedic joint comprising a sensor, and

the determining step comprises monitoring output from the sensor.

14. The method ofclaim 1, wherein the orthopaedic joint of the patient comprises at least one natural joint component.

15. The method ofclaim 1, wherein the orthopaedic joint of the patient comprises at least one prosthetic joint component.

16. The method ofclaim 1, wherein the initiating step comprises generating an automated, device-initiated electronic communication.

17. The method ofclaim 1, wherein:

the determining step comprises determining the number of cycles of use of the orthopaedic joint and generating an output signal in response thereto, and

the initiating step comprises generating an automated, device-initiated electronic communication with an electronic device of the orthopaedic care provider in response to generation of the output signal.

18. The method ofclaim 1, wherein the determining step comprises determining the distance between a first component and a second component of the orthopaedic joint of the patient.

19. A patient monitoring system, comprising:

a sensor,

a processor in communication with the sensor, and

a memory device electrically coupled to the processor, the memory device having stored therein a plurality of instructions which, when executed by the processor, cause the processor to:

monitor output from the sensor to determine the number of cycles of use of the orthopaedic joint of a patient, and

generate a message to the patient indicative of a need to initiate communication with an orthopaedic care provider if the number of cycles of use of the orthopaedic joint exceeds a predetermined threshold value.

20. The patient monitoring system ofclaim 19, wherein the sensor is implantable into the body of the patient.

21. The patient monitoring system ofclaim 19, wherein the sensor is configured to be externally worn by the patient.

22. The patient monitoring system ofclaim 19, wherein the sensor is secured to a prosthetic joint component.

23. A method of determining patient follow-up subsequent to an orthopaedic procedure, the method comprising the steps of:

electronically querying a joint use measurement device to determine the number of cycles of use of an orthopaedic joint of a patient, and

generating an electronic output signal if the number of cycles of use of the orthopaedic joint of the patient exceeds a predetermined threshold value.

24. The method ofclaim 23, wherein the generating step comprises generating a phone message which is sent to an orthopaedic care provider.

25. The method ofclaim 23, wherein the generating step comprises generating an electronic mail message which is sent to an orthopaedic care provider.

26. The method ofclaim 23, wherein:

the joint use measurement device comprises a sensor implanted into the body of the patient, and

the electronically querying step comprises determining output from the sensor.

27. The method ofclaim 23, wherein

the joint use measurement device is configured to be externally worn by the patient,

the joint use measurement device comprises a sensor, and the electronically querying step comprises determining output from the sensor.

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