Method and apparatus for use in balancing ligaments of a knee

• US 7,615,055 B2
• Filed: 03/31/2005
• Issued: 11/10/2009
• Est. Priority Date: 03/31/2005
• Status: Active Grant

• Current Assignee: Depuy Products Incorporated (Johnson & Johnson)
• Original Assignee: Depuy Products Incorporated (Johnson & Johnson)
• Inventors: DiSilvestro, Mark R.
• Primary Examiner(s): Barrett; Thomas C
• Assistant Examiner(s): WOODALL, NICHOLAS W
• Application Number:
  US11/094,956
• Publication Number:
  US 20060241569A1
• Time in Patent Office: 1,685 Days
• Field of Search: 600594-595, 606/88, 606/90
• US Class Current: 606/88
• CPC Class Codes: A61B 2017/0268 for the knee
• CPC Class Codes: A61F 2/38 for elbows or knees
• CPC Class Codes: A61F 2/461 of knees
• CPC Class Codes: A61F 2/4657 Measuring instruments used for implanting artificial joints for surgical instruments A61B90/06
• CPC Class Codes: A61F 2002/4632 using computer-controlled surgery, e.g. robotic surgery
• CPC Class Codes: A61F 2002/4658 for measuring dimensions, e.g. length
• CPC Class Codes: A61F 2002/4666 for measuring force, pressure or mechanical tension
• CPC Class Codes: A61F 2002/4696 optical

Abstract

An apparatus for use in performing an orthopaedic surgical procedure on a patient includes at least one femoral paddle and a tibial paddle. At least one of the femoral paddle and the tibial paddle is movable away from the other. The apparatus also includes a sensor configured to generate a signal indicative of a force applied to the femoral paddle or the tibial paddle. The apparatus may be communicatively coupled to a computer assisted orthopaedic surgery system.

Claims

1. An apparatus for use in performing an orthopaedic surgical procedure on a patient, the apparatus comprising:

a tibial paddle having spaced-apart medial and lateral portions configured to contact respective medial and lateral sides of a proximal tibia of the patient;

a medial femoral paddle configured to contact a medial side of a distal femur of the patient and positioned over the tibial paddle;

a lateral femoral paddle spaced-apart from the medial femoral paddle, configured to contact a lateral side of the distal femur of the patient and positioned over the tibial paddle;

a housing, wherein the tibial paddle, the medial femoral paddle, and the lateral femoral paddle are each coupled to the housing;

an actuator operatively coupled to the at least one of the medial femoral paddle and the lateral femoral paddle;

a sensor configured to generate an electrical output signal indicative of a force applied to the at least one of the medial femoral paddle and the lateral femoral paddle;

a user interface coupled to and positioned on the housing; and

a controller, coupled to the housing and operable to (i) receive the electrical output signal from the sensor, (ii) determine a force value based on the electrical output signal, and (iii) display the force value on the user interface, the controller including a memory device operable to store a digital representation of the force value,

wherein the controller is responsive to (i) a first user input received via the user interface to store the force value in the memory device and (ii) a second user input received via the user interface to retrieve the stored force value and control the actuator to move the at least one of the medial femoral paddle and the lateral femoral paddle away from the tibial paddle until the force applied to the at least one of the medial femoral paddle and the lateral femoral paddle is equal to the stored force value.

2. The apparatus of claim 1, wherein the actuator is a stepper motor.

3. The apparatus of claim 1, wherein the actuator is a linear actuator.

4. The apparatus of claim 1, wherein the sensor is a load cell.

5. The apparatus of claim 1, further comprising a distance sensor configured to generate a distance signal indicative of a distance between at least one of the medial and lateral femoral paddles and the tibial paddle.

6. The apparatus of claim 1, wherein the user interface includes a number of buttons.

7. The apparatus of claim 1, wherein the user interface includes a display.

8. The apparatus of claim 1, further comprising a distance sensor configured to generate an electrical distance signal indicative of a distance between at least one of the medial and lateral femoral paddles and the tibial paddle, and wherein the controller is configured to (i) receive the electrical distance signal, (ii) determine a distance value based on the electrical distance signal, and (iii) display the distance value on the user interface.

9. The apparatus of claim 8, wherein the controller includes a memory device and is configured to store a digital representation of the distance signal.

10. The apparatus of claim 9, wherein the controller is responsive to a user input received via the user interface to retrieve a stored distance value from the memory device and control the means for moving the at least one of the medial femoral paddle, the lateral femoral paddle and the tibial paddle to move the at least one of the medial femoral paddle and the lateral femoral paddle away from the tibial paddle to a distance equal to the stored distance value.

11. The apparatus of claim 1, further comprising a transmitter configured to transmit measurement data.

12. The apparatus of claim 11, wherein the measurement data includes data indicative of the force applied to at least one of the medial and lateral femoral paddles.

13. The apparatus of claim 11, wherein the measurement data includes data indicative of a distance between at least one of the medial and lateral femoral paddles and the tibial paddle.

14. The apparatus of claim 1, further comprising a receiver configured to receive control signals from a computer assisted orthopedic surgical system.

15. The apparatus of claim 14, further comprising a second controller communicatively coupled to the receiver and configured to control the actuator in response to the control signals.

16. A ligament balancer comprising:

a medial paddle configured to contact a medial side of a distal femur of a patient;

a lateral paddle spaced-apart from the medial paddle and configured to contact a lateral side of the distal femur of the patient, wherein at least one of the medial and lateral paddles is configured to move in an inferior and a superior direction;

a first electrically driven actuator configured to move the medial paddle in the inferior direction and the superior direction;

a second electrically driven actuator configured to move the lateral paddle in the inferior direction and the superior direction;

a first sensor configured to generate a first electrical output signal indicative of a force applied to the medial paddle;

a second sensor configured to generate a second electrical output signal indicative of a force applied to the lateral paddle;

a housing, wherein the medial paddle and the lateral paddle are each coupled to the housing;

a user interface coupled to and positioned on the housing; and

a controller coupled to the housing and operable to (i) receive the first electrical output signal and the second electrical output signal, (ii) determine a first force value based on the first electrical output signal and a second force value based on the second electrical output signal, and (iii) display the first force value and the second force value on the user interface,

wherein the controller is responsive to (i) a first user input received via the user interface to store the first force value, (ii) a second user input received via the user interface to store the second force value, and (iii) a third user input received via the user interface to retrieve the first stored force value to control the first actuator to move the medial paddle until the force applied to the medial paddle is equal to the first stored force value and retrieve the second stored value to control the second actuator to move the lateral paddle until the force applied to the lateral paddle is equal to the second stored force value.

17. A ligament balancer comprising:

a tibial paddle configured to contact a proximal tibia of a patient;

a medial femoral paddle configured to contact a medial side a distal femur of the patient;

a lateral femoral paddle spaced-apart from the medial femoral paddle and configured to contact a lateral side of the distal femur;

a first electrically driven actuator operable to move the medial femoral paddle;

a second electrically driven actuator operable to move the lateral femoral paddle;

a first sensor configured to generate a first electrical output signal indicative of a distance between the medial femoral paddle and the tibial paddle;

a second sensor configured to generate a second electrical output signal indicative of a distance between the lateral femoral paddle and the tibial paddle;

a housing, wherein the medial femoral paddle, the lateral femoral paddle, and the tibial paddle are each coupled to the housing;

a user interface coupled to and positioned on the housing; and

a controller coupled to the housing and operable to (i) receive the first electrical output signal and the second electrical output signal, (ii) determine a first distance value based on the first electrical output signal and a second distance value based on the second electrical output signal, and (iii) display the first distance value and the second distance value on the user interface, the controller including a memory device operable to store a digital representation of the first distance value and the second distance value,

wherein the controller is responsive to (i) a first user input received via the user interface to store the first distance value and the second distance value in the memory device, and (ii) a second user input received via the user interface to retrieve the first stored distance value to control the first actuator to move the medial femoral paddle away from the tibial paddle to a distance equal to the first stored distance value and retrieve the second stored distance value to control the second actuator to move the lateral femoral paddle away from the tibial paddle to a distance equal to the second stored distance value.

18. A ligament balancer comprising:

a medial paddle configured to contact a medial side of a distal femur of a patient and movable in at least one of an inferior and a superior direction between a first and second medial position;

a lateral paddle spaced-apart from the medial paddle, configured to contact a lateral side of the distal femur of the patient, and movable in at least one of an inferior and a superior direction between a first and second lateral position;

an electrically driven actuator configured to move at least one of the medial and lateral paddles between the respective first and second medial and lateral positions in response to a control signal;

a sensor configured to generate an electrical output signal indicative of a force applied to the at least one of the medial paddle and lateral paddle;

a housing, wherein the medial paddle, the lateral paddle, and the electrically driven actuator, are each coupled to the housing; and

a user interface coupled to and positioned on the housing;

a controller coupled to the housing and operable to (i) receive the electrical output signal from the sensor, (ii) determine a force value based on the electrical output signal, and (iii) display the force value on the user interface, the controller including a memory device operable to store a digital representation of the force value,

wherein the controller is responsive to (i) a first user input received via the user interface to store the force value in the memory device and (ii) a second user input received via the user interface to retrieve the stored force value and control the actuator to move the at least one of the medial and lateral paddles until the force applied to the at least one of the medial and lateral paddles is equal to the stored force value.

19. The ligament balancer of claim 18, wherein the electrically driven actuator is a stepper motor.

20. The ligament balancer of claim 18, wherein the electrically driven actuator is a linear actuator.