System and method for measuring muscular-skeletal alignment to a mechanical axis
First Claim
1. A method of measuring alignment to a mechanical axis of a muscular-skeletal system comprising the steps of:
- moving a joint through a first movement wherein a single tracking device is coupled to the joint, wherein the joint is moved between a first point and a second wherein the first movement pivots from a first pivot point, wherein a reference position of the joint is approximately centered between the first point and the second point, wherein the first point is 45 degrees or less from the reference position, and wherein the second point is 45 degrees or less from the reference position;
sending tracking measurement data to a computer wherein a joint position is tracked and wherein the tracking measurement data comprises a plurality of position measurements throughout the first movement;
moving the joint through a second movement;
sending tracking measurement data to the computer wherein a joint position is tracked and wherein the tracking measurement data comprises a plurality of position measurements from throughout the second movement; and
calculating alignment relative to a mechanical axis wherein the computer uses the tracking measurement data from the first and second movements to calculate alignment wherein the first movement measures a varus or valgus number relative to the mechanical axis of the first bone and wherein the second movement measures a varus or valgus number of the second bone relative to the mechanical axis; and
subtracting the varus or valgus number of the second bone from the varus or valgus number of the first bone to calculate the alignment of the first and second bones to the mechanical axis.
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Accused Products
Abstract
A system and method is disclosed herein for measuring alignment of the muscular-skeletal system. The system comprises a sensored module that can be placed within a prosthetic component to measure load, position of load, and joint alignment. The system further includes a remote system for receiving, processing, and displaying quantitative measurements from the sensors. Alignment relative to a mechanical axis is measured. In a two bone system with a joint therebetween the total alignment measured comprises offsets measured for each bone. The joint is placed in a predetermined flexion that supports measurement of the joint as it is moved. The joint pivots on a point that is along the mechanical axis. Points along the arc made by the joint rotating between a first and second point are measured. An arc maximum is determined. The arc maximum is then converted to varus or valgus offset relative to the mechanical axis.
148 Citations
15 Claims
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1. A method of measuring alignment to a mechanical axis of a muscular-skeletal system comprising the steps of:
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moving a joint through a first movement wherein a single tracking device is coupled to the joint, wherein the joint is moved between a first point and a second wherein the first movement pivots from a first pivot point, wherein a reference position of the joint is approximately centered between the first point and the second point, wherein the first point is 45 degrees or less from the reference position, and wherein the second point is 45 degrees or less from the reference position; sending tracking measurement data to a computer wherein a joint position is tracked and wherein the tracking measurement data comprises a plurality of position measurements throughout the first movement; moving the joint through a second movement; sending tracking measurement data to the computer wherein a joint position is tracked and wherein the tracking measurement data comprises a plurality of position measurements from throughout the second movement; and calculating alignment relative to a mechanical axis wherein the computer uses the tracking measurement data from the first and second movements to calculate alignment wherein the first movement measures a varus or valgus number relative to the mechanical axis of the first bone and wherein the second movement measures a varus or valgus number of the second bone relative to the mechanical axis; and subtracting the varus or valgus number of the second bone from the varus or valgus number of the first bone to calculate the alignment of the first and second bones to the mechanical axis. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of measuring alignment to a mechanical axis of a muscular-skeletal system comprising the steps of:
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moving a joint through a first movement wherein a single tracking device is coupled to the joint, wherein the joint is moved between a first point and a second at least two times, wherein the first movement pivots from a first pivot point, wherein a reference position of the joint is approximately centered between the first point and the second point, wherein the first point is 45 degrees or less from the reference position, wherein the second point is 45 degrees or less from the reference position, wherein the joint is positioned such that the tracking device is at approximately a 45 degree angle to a plane of a surface when pivoting on the first pivot point, wherein the first pivot point couples to the surface; measuring points of an arc generated as the joint is moved between the first and second points; sending tracking measurement data to a computer wherein a joint position is tracked and wherein the tracking measurement data comprises a plurality of position measurements throughout the first movement; determining a maximum of the arc; moving the joint through a second movement; sending tracking measurement data to the computer wherein a joint position is tracked and wherein the tracking measurement data comprises a plurality of position measurements from throughout the second movement; calculating a tilt value of a bone cut of a first bone wherein the tracking measurement data is used by the computer to calculate the tilt value; converting the tilt value to a varus or valgus number in relation to a mechanical axis the joint for the first bone wherein the computer calculates the varus or valgus number; calculating a tilt value of a bone cut of a second bone wherein the tracking measurement data is used by the computer to calculate the tilt value; converting the tilt value to a varus or valgus number in relation to a mechanical axis of the joint for the second bone wherein the computer calculates the varus or valgus number; and subtracting the varus or valgus number of the second bone from the varus or valgus number of the first bone to calculate the alignment of the first and second bones to the mechanical axis. - View Dependent Claims (12, 13, 14, 15)
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Specification