Method and apparatus for locating bone cuts at the distal condylar femur region to receive a knee prosthesis
First Claim
1. A method for forming planar resections on the medial and lateral condyles of a femur of a knee to form seating surfaces to receive a femoral prosthesis and to properly articulate with a tibial and patellar prosthesis, said method comprising:
- determining a prospective planar resection to be made at the posterior medial and lateral condyles of a femur at which a distance between an anterior surface of the femoral cortex and the prospective planar resection is substantially equal to an interior dimension of a femoral prosthesis to be fitted on said femur,said planar resection producing resection of the medial and lateral condyles at said posterior surface of respective thicknesses which are not necessarily equal,measuring the thicknesses which will be resected by said planar resection at said medial and lateral condyles at said posterior surface,resecting a distal end of the medial and lateral condyles along a plane which produces respective resected thicknesses, not necessarily equal, at said medial and lateral condyles and wherein the distal medial resection is substantially equal to the measured posterior medial condyle thickness to be resected and the distal lateral resection is substantially equal to the measured posterior lateral condyle thickness to be resected, andresecting the medial and lateral condyles along a plane at the anterior surfaces thereof substantially flush with the anterior surface of the femoral cortex, and along said prospective planar resection.
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Accused Products
Abstract
A tool mountable on an intramedullary rod projecting from the distal end of a femur, the tool carrying anterior and posterior caliper feelers for respectively engaging the anterior surface of the femoral cortex and the posterior surfaces of the condyles of the femur. The tool is adapted to be rotated with the rod to a determined angular position. The caliper feelers are supported on the tool to measure the perpendicular distance between the anterior surface of the femoral cortex and a plane inclined about an axis located in another plane tangent to the posterior surfaces of the medial and lateral condyles and at an angle correlated to the angle of rotation of the tool. A scale on the tool indicates prosthesis size on the basis of the distance measured. A distal cutting guide is mountable on the tool while still on the rod and the cutting guide has a guide slot for a cutting tool to form a planar cut at a distal end of the femur to resect a thickness of the femur based on the distance measured by the caliper feelers. Thereafter, a conventional A-P cutting guide is mounted on the rod or a pair of reference pins to enable anterior and posterior cuts to be made.
237 Citations
49 Claims
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1. A method for forming planar resections on the medial and lateral condyles of a femur of a knee to form seating surfaces to receive a femoral prosthesis and to properly articulate with a tibial and patellar prosthesis, said method comprising:
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determining a prospective planar resection to be made at the posterior medial and lateral condyles of a femur at which a distance between an anterior surface of the femoral cortex and the prospective planar resection is substantially equal to an interior dimension of a femoral prosthesis to be fitted on said femur, said planar resection producing resection of the medial and lateral condyles at said posterior surface of respective thicknesses which are not necessarily equal, measuring the thicknesses which will be resected by said planar resection at said medial and lateral condyles at said posterior surface, resecting a distal end of the medial and lateral condyles along a plane which produces respective resected thicknesses, not necessarily equal, at said medial and lateral condyles and wherein the distal medial resection is substantially equal to the measured posterior medial condyle thickness to be resected and the distal lateral resection is substantially equal to the measured posterior lateral condyle thickness to be resected, and resecting the medial and lateral condyles along a plane at the anterior surfaces thereof substantially flush with the anterior surface of the femoral cortex, and along said prospective planar resection. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 32, 33, 34)
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12. A method for forming three planar resections on the medial and lateral condyles of a femur to form seating surfaces to receive a femoral prosthesis and to properly articulate with a tibial and patellar prosthesis, said method comprising:
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determining a prospective planar resection to be made at the posterior of the medial and lateral condyles of a femur at which a distance between an anterior surface of the femoral cortex and the prospective planar resection is substantially equal to an interior dimension of a femoral prosthesis to be fitted on said femur, measuring a thickness to be resected by said prospective planar resection at the posterior surface of the medial and lateral condyles by measuring a distance between said anterior surface of the femoral cortex and a plane parallel to said prospective planar resection, resecting distal ends of the medial and lateral condyles along a plane which produces respective resected thicknesses, not necessarily equal, at said medial and lateral condyles and wherein the distal medial resection is substantially equal to the measured posterior medial condyle thickness to be resected and the distal lateral resection is substantially equal to the measured posterior lateral condyle thickness to be resected, and resecting the medial and lateral condyles along a plane at the anterior surfaces thereof substantially flush with the anterior surface of the femoral cortex, and along a plane containing said prospective planar resection. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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20. A tool for enabling resections to be made on the medial and lateral femoral condyles of a knee for installation of a femoral prosthesis, said tool comprising
means for engaging an intramedullary rod in a femur to rotate said tool on said rod through an angle to a determined angular or rotational position about plus or minus 15° - relative to a plane tangent to posterior surfaces of the medial and lateral condyles,
means for measuring a distance between an anterior femoral cortex surface and a plane inclined, with respect to the plane tangent to the posterior surfaces of the medial and lateral condyles about an axis located in said plane, at an angle equal to the angle of rotation of said tool on said rod when moved to said determined angular or rotational position, and means for mounting a guide on the tool while the tool remains engaged on the intramedullary rod, said guide having guide slots to pass a resector to produce an anterior or distal resection on the condyles. - View Dependent Claims (21, 22, 23, 24, 25, 26)
- relative to a plane tangent to posterior surfaces of the medial and lateral condyles,
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27. A tool mountable on an intramedullary rod loosely mounted in a femur to rotate the rod and tool and to measure an anterior-posterior dimension taking into account the rotation and angulation of the tool, said tool comprising:
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an engaging device for engaging an intramedullary rod loosely mounted in a femur having an anterior femoral cortex to rotate said tool therewith, an anterior feeler for contacting the anterior cortex surface of the femur, a posterior feeler or feelers for contacting posterior surfaces of medial and lateral condyles to establish a plane tangent to said posterior surfaces, a caliper for measuring the distance between the anterior femoral cortex and the posterior femoral condyles, said caliper being operatively engaged to said engaging device and to said anterior and posterior feelers, a pivot between said caliper and said posterior feeler for providing relative pivotable movement therebetween about an axis disposed in said tangent plane, and means providing relative movement between said pivot and said engaging means to permit said tool to be rotated on said rod at least about plus or minus 15° and
said caliper to be rotated around said pivot so that the caliper is positioned to measure an anterior-posterior dimension represented by a distance from said anterior cortex surface to said tangent plane which is inclined at an angle equal to said angle at which the tool and caliper have been rotated. - View Dependent Claims (28, 29)
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30. A method for forming planar resections on the medial and lateral condyles of a femur of a knee to form seating surfaces to receive a femoral prosthesis to properly articulate with a tibial and patellar prosthesis, said method comprising:
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measuring the thicknesses which will be resected by a prospective planar resection to be made at the posterior of the medial and lateral condyles of a femur at which a distance between an anterior surface of the femoral cortex and the prospective planar resection is substantially equal to an interior dimension of a femoral prosthesis to be fitted on said femur, said planar resection producing resection of the medial and lateral condyles at said posterior surface of respective thicknesses which are not necessarily equal, resecting a distal end of the medial and lateral condyles along a plane which produces respective resected thicknesses, not necessarily equal, at said medial and lateral condyles and wherein the distal medial resection is usually substantially equal to the measured posterior medial condyle thickness to be resected and the distal lateral resection is usually substantially equal to the measured posterior lateral condyle thickness to be resected, and resecting the medial and lateral condyles along a plane at the anterior surfaces thereof substantially flush with the anterior surface of the femoral cortex, and along said prospective planar resection.
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31. A method for forming planar resections on the medial and lateral condyles of a femur of a knee to form seating surfaces to receive a femoral prosthesis to properly articulate with a tibial and patellar prosthesis, said method comprising:
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measuring the thicknesses which will be resected by a prospective planar resection to be made at the posterior of the medial and lateral condyles of a femur at which a distance between an anterior surface of the femoral cortex and the prospective planar resection is substantially equal to an interior dimension of a femoral prosthesis to be fitted on said femur, said planar resection producing resection of the medial and lateral condyles at said posterior surface of respective thicknesses which are not necessarily equal, resecting the medial and lateral condyles along a plane at the anterior surfaces thereof substantially flush with the anterior surface of the femoral cortex, resecting a distal end of the medial and lateral condyles along a plane which produces respective resected thicknesses, not necessarily equal, at said medial and lateral condyles and wherein the distal medial resection is substantially equal to the measured posterior medial condyle thickness to be resected and the distal lateral resection is substantially equal to the measured posterior lateral condyle thickness to be resected, and resecting the medial and lateral condyles along said measured prospective planar resection.
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35. A method for forming planar resections on the medial and lateral condyles of a femur to form seating surfaces to receive a femoral prosthesis and to properly articulate with a tibial and patellar prosthesis, said method comprising:
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measuring for the size of the femoral prosthesis to be received by determining a first distance between an anterior surface of the femoral cortex and a plane tangent to a posterior surface of the medial and lateral condyles of a femur; using a graduated scale to compare the first distance to at least two standard femoral prosthesis sizes; measuring a second distance between the first distance and the size of a larger standard femoral prosthesis size; measuring a thickness or thicknesses to be resected at the posterior surface of the medial and lateral condyles of the femur, the thickness being equal to the difference between the thickness of the posterior condyles of the larger standard femoral prosthesis and the second distance; resecting the medial and lateral condyles along a plane at the anterior surfaces thereof substantially flush with the anterior surface of the femoral cortex; and resecting distal ends of the medial and lateral condyles along a plane which produces respective resected thicknesses at said medial and lateral condyles, not necessarily equal, wherein the distal medial resection is substantially equal to the measured posterior medial condyle thickness and the distal lateral resection is substantially equal to the measured posterior lateral condyle thickness.
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36. An apparatus for forming planar resections on the medial and lateral condyles of a femur to form seating surfaces to receive a femoral prosthesis and to properly articulate with a tibial and patellar prosthesis, said apparatus comprising:
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a caliper feeler and measurement plate to measure for the size of the femoral prosthesis to be received, said caliper feeler and measurement plate adapted to determine a first distance between an anterior surface of the femoral cortex and a plane tangent to a posterior surface of the medial and lateral condyles of a femur, the caliper feeler referencing the anterior surface of the femoral cortex and the measurement plate referencing the plane tangent to the posterior surface of the medial and lateral condyles; a graduated scale to compare the first distance to at least two standard femoral prosthesis sizes and to determine the smaller of the at least two standard femoral prosthesis sizes; a graduated scale to measure a second distance between the first distance and the size of the smaller standard femoral prosthesis size, so that a thickness or thicknesses can be measured to be resected at the posterior surface of the medial and lateral condyles of the femur by adding the thickness of the posterior condyles of the smaller standard femoral prosthesis and the second distance; a tool to resect the medial and lateral condyles along a plane at the anterior surfaces thereof flush with the anterior surface of the femoral cortex; and a tool to resect distal ends of the medial and lateral condyles along a plane which produces respective resected thicknesses at said medial and lateral condyles, not necessarily equal, wherein the distal medial resection is substantially equal to the measured posterior medial condyle thickness and the distal lateral resection is substantially equal to the measured posterior lateral condyle thickness. - View Dependent Claims (37, 38, 39, 40, 41, 42, 43, 44)
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45. A method for forming planar resections on the medial and lateral condyles of a femur to form seating surfaces to receive a femoral prosthesis and to properly articulate with a tibial and patellar prosthesis, said method comprising:
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measuring for the size of the femoral prosthesis to be received by determining a first distance between an anterior surface of the femoral cortex and a plane tangent to a posterior surface of the medial and lateral condyles of a femur; using a graduated scale to compare the first distance to at least two standard femoral prosthesis sizes; measuring a second distance between the first distance and the size of the smaller standard femoral prosthesis size; measuring a thickness or thicknesses to be resected at the posterior surface of the medial and lateral condyles of the femur, the thickness being equal to the thickness of the posterior condyles of the smaller standard femoral prosthesis plus the second distance; and measuring a thickness or thicknesses to be resected at the distal ends of the medial and lateral condyles, the thickness being equal to the thickness of the distal surface of the smaller standard femoral prosthesis plus the second distance. - View Dependent Claims (46, 47, 48)
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49. A method for forming planar resections on the medial and lateral condyles of a femur to form seating surfaces to receive a femoral prosthesis and to properly articulate with a tibial and patellar prosthesis, said method comprising:
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measuring for the size of the femoral prosthesis to be received by determining a first distance between an anterior surface of the femoral cortex and a plane tangent to a posterior surface of the medial and lateral condyles of a femur; using a graduated scale to compare the first distance to at least two standard femoral prosthesis sizes; measuring a second distance between the first distance and the size of the larger standard femoral prosthesis size; measuring a thickness or thicknesses to be resected at the posterior surface of the medial and lateral condyles of the femur, the thickness being equal to the difference between the thickness of the posterior condyles of the larger standard femoral prosthesis and the second distance; resecting the medial and lateral condyles along a plane at the anterior surfaces thereof substantially flush with the anterior surface of the femoral cortex; and measuring a thickness or thicknesses to be resected at the distal ends of the medial and lateral condyles, the thickness being equal to the difference between the thickness of the distal surface of the larger standard femoral prosthesis and the second distance.
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Specification