Lower extremities leg length calculation method
A method of calculating leg length discrepancy of a patient including: receiving patient bone data associated with a lower body of the patient; identifying anatomical landmarks in the patient bone data; orienting a first proximal landmark and a second proximal landmark relative to each other and an origin in a coordinate system; aligning a first axis associated with a first femur and a second axis associated with a second femur with a longitudinal axis extending in a distal-proximal direction, wherein the first and second distal landmarks are adjusted according to the alignment of the first and second axes; calculating a distance between the first and second distal landmarks in the distal-proximal direction along the longitudinal axis; and displaying at least one of the distance or a portion of the patient bone data on a display screen.
1. A computer program stored on one or more tangible, non-transitory, computer-readable storage media having executable instructions for performing the computer program on a computing system, the computer program comprising:
receiving patient bone data having a first side and a second side, one of the first or second sides including a degenerate or deformed condition;
generating a computer model of the first and second sides from the patient bone data;
identifying anatomical landmarks in the patient bone data or the computer model, the anatomical landmarks comprising: a first proximal point and a first distal point on the first side; and a second proximal point and a second distal point on the second side;
orienting the first and second sides of the computer model relative to each other in a coordinate system such that: a pelvic axis extending through the first and second proximal points are generally perpendicular to a longitudinal axis of the first and second sides of the computer model; and a first axis associated with a first femur and a second axis associated with a second femur are generally parallel to the longitudinal axis;
calculating a leg length discrepancy based on the first and second sides of the computer model after orienting the first and second sides of the computer model relative to each other.
2. The computer program of claim 1 , wherein the first proximal point corresponds to a femoral head center of a first femur of the first side of the patient bone data, and the second proximal point corresponds to a femoral head center of a second femur of the second side of the patient bone data.
3. The computer program of claim 1 , wherein the first distal point corresponds to a first point in or on a first bone in a first foot region of the first side of the patient bone data, and the second distal point corresponds to a second point in or on a second bone in a second foot region of the second side of the patient bone data.
4. The computer program of claim 1 , further comprising: adjusting an orientation of at least one of a first knee joint of the computer model defined between a first femur and a first tibia of the first side of the patient bone data or a second knee joint of the computer model defined between a second femur and a second tibia of the second side of the patient bone data.
5. The computer program of claim 1 , wherein the patient bone data comprises at least one of CT images, MR images, or X-ray images.
6. The computer program of claim 1 , wherein the leg length discrepancy comprises determining a distance between the first and second distal points in a direction of the longitudinal axis.
7. The computer program of claim 1 , wherein the leg length discrepancy comprises determining a difference between a first distance and a second distance, the first distance defined between the first proximal point and the first distal point on the first side, the second distance defined between the second proximal point and the second distal point on the second side.