Natural alignment knee instruments
First Claim
1. A method for replacing a knee joint, comprising:
- determining a naturally occurring joint surface on a distal femur;
assessing a deficiency on the distal femur from the naturally occurring joint surface;
selecting an offset distance between first and second reference surfaces of an instrument based on the deficiency;
contacting the distal femur with the first and second reference surfaces to determine an orientation of the instrument and a first guide surface relative to the distal femur; and
resecting the distal femur by guiding a cutting tool along the first guide surface to form a distal resection.
1 Assignment
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Accused Products
Abstract
A method for aligning an orthopedic implant in a joint replacement includes determining the bone and cartilage deficiency from an undegenerated state caused by wear of a joint. Then a resection of a bone in the joint is made based on the deficiency of bone and cartilage from the undegenerated state and the size of a joint implant so as to locate the joint surface of the implant in the undegenerated cartilage location. The condylar wear from the undegenerated states may be assessed at a distal and posterior location on each of a medial and a lateral femoral condyle. A distal cut is made on the femur at a location adjusting for the condylar wear from the undegenerated state. The distal cut varus-valgus angle is oriented parallel to a plane across the distal femur after adjusting for wear in the distal location on the medial and lateral condyle.
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Citations
25 Claims
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1. A method for replacing a knee joint, comprising:
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determining a naturally occurring joint surface on a distal femur; assessing a deficiency on the distal femur from the naturally occurring joint surface; selecting an offset distance between first and second reference surfaces of an instrument based on the deficiency; contacting the distal femur with the first and second reference surfaces to determine an orientation of the instrument and a first guide surface relative to the distal femur; and resecting the distal femur by guiding a cutting tool along the first guide surface to form a distal resection. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A method for resecting a distal femur and a tibia to receive a joint implant, comprising:
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determining a distal extent of a degenerated joint surface of the distal femur; determining an amount of degeneration at a first region of the distal femur; determining a distal extent of a pre-degenerated joint surface of the distal femur based on the distal extent of the degenerated joint surface and the amount of degeneration; contacting the distal femur in the first region with a first reference surface of an instrument and a second region with a second reference surface of the instrument, the first and second reference surfaces being separated by an offset distance based on the amount of degeneration, the offset distance and contact of the first region with the first reference surface and second region with the second reference surface aligns the instrument with the pre-degenerated joint surface; and resecting the distal femur along a resection plane a predetermined distance from and in a predetermined orientation with respect to the pre-degenerated joint surface to form a distal resection. - View Dependent Claims (16, 17, 18, 19, 20)
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21. A method for resecting a distal femur and a tibia to receive a joint implant, comprising:
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determining a first amount of degeneration of a first condyle and a second amount of degeneration of a second condyle; determining a relative degeneration based on a difference between the first and second amounts of degeneration; contacting the first condyle with a first reference surface of an instrument; contacting the second condyle with a second reference surface of the instrument, the first and second reference surfaces being separated by an offset distance based on the relative degeneration; and resecting the distal femur a predetermined distance from the instrument based on a thickness of an implant so as to locate a joint surface of the implant in substantially the same location as a pre-degenerated joint surface defined by the first and second condyles prior to the first and second amounts of degeneration being formed. - View Dependent Claims (22, 23, 24)
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25. A method of resecting a distal femur, comprising:
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contacting a degenerated portion of a joint surface of a distal femur with a first bone contact surface of an instrument; contacting an undegenerated portion of the joint surface with a second bone contact surface of the instrument, the second bone contact surface being offset from the first bone contact surface a distance based on an amount of degeneration of the joint surface at the degenerated portion such that when the first bone contact surface contacts the degenerated portion and the second contact surface contacts the undegenerated portion, the instrument is aligned with a pre-degenerated joint-line of the distal femur; and resecting the distal femur at a location parallel to the pre-degenerated joint-line.
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Specification