Surgical orientation device and method
A device for detecting and measuring a change in angular position with respect to a reference plane is useful in surgical procedures for orienting various instruments, prosthesis, and implants with respect to anatomical landmarks. One embodiment of the device uses three orthogonal rate sensors, along with integrators and averagers, to determine angular position changes using rate of change information. A display provides position changes from a reference position. Various alignment guides are useful with surgical instruments to obtain a reference plane.
1. A system for preparing a knee structure of a patient to receive a medical implant and for aligning the implant with respect to an anatomical location in the patient, the system comprising:
a first instrument configured to engage at least a portion of the knee structure of the patient and to be oriented with respect to the anatomical location, the first instrument configured to prepare the knee structure to receive the implant, the anatomical location relating to a knee joint location near the proximal portion of the tibia and the distal portion of the femur, the first instrument comprising:
an elongate alignment guide for aligning the tibia with respect to the anatomical location;
a cutting block coupled to the alignment guide, the cutting block configured to engage at least the proximal portion of the tibia;
a proximal portion for engaging the knee joint location; and
a distal portion;
a second instrument configured to engage at least a distal portion of the femur and to be oriented with respect to the anatomical location; and
a surgical orientation device attached to the first instrument and configured to be selectively attachable and detachable with the first instrument and the second instrument, the surgical orientation device when detached being a hand-held, stand alone device having an internal reference frame for placing the proximal portion of the tibia or the distal portion of the femur in a desired position with respect to the anatomical location, the orientation device comprising:
a housing containing a plurality of electronic components, the components comprising:
at least one sensor for providing a signal corresponding to angular position of the orientation device;
a microprocessor in communication with the at least one sensor and programmed to calculate, using at least the signal and the reference frame, a first angle of the surgical orientation device relative to a first axis and a second angle of the surgical orientation device relative to a second axis;
a display electronically coupled to the microprocessor for displaying the first and second angles when the surgical orientation device is attached to the first or second instrument, and
a zeroing device for re-setting the surgical orientation device relative to the reference frame.
2. The system for preparing a knee structure of claim 1 , wherein the cutting block is disposed at a proximal portion of the first instrument.
3. The system for preparing a knee structure of claim 1 , wherein the second instrument comprises a distal femoral cutting block configured to be coupled with the surgical orientation device to a distal portion of a femur.
4. The system for preparing a knee structure of claim 3 , wherein the distal femoral cutting block is configured to be coupled with a distal end of the femur after a condyle cut.
5. The system for preparing a knee structure of claim 1 , wherein the at least one sensor comprises a gyroscopic sensor.
6. The system for preparing a knee structure of claim 1 , wherein the surgical orientation device is coupled with a proximal portion of the first instrument to provide flexion and extension gap alignment.
7. The system claim 1 , wherein the cutting block is disposed at a proximal end of the first instrument or the alignment guide.
8. The system of claim 1 , wherein the at least one sensor comprises an accelerometer.
9. The system of claim 1 wherein the alignment guide is movably coupled to the first instrument.
10. The system of claim 1 wherein the surgical orientation device is configured to align the tibia to a desirable degree of varus/valgus.
11. The system of claim 1 wherein the surgical orientation device is configured to align the tibia to a desirable degree of posterior slope.
12. The system of claim 1 , wherein the display comprises numeric representations representing numbers of degrees of alignment.
13. The system of claim 1 wherein the second instrument comprises a second cutting block.