METHODS OF PREDETERMINING THE CONTOUR OF A RESECTED BONE SURFACE AND ASSESSING THE FIT OF A PROSTHESIS ON THE BONE
Methods for predetermining a contour of a resected bone surface and assessing a fit of a prosthesis on the resected bone surface, for designing prostheses to fit discrete patient populations, and for designing customized prostheses.
The present application is a divisional application of U.S. patent application Ser. No. 11/685,906, docket ZIM0317-01, titled METHODS OF PREDETERMINING THE CONTOUR OF A RESECTED BONE SURFACE AND ASSESSING THE FIT OF A PROSTHESIS ON THE BONE, which claims the benefit under Title 35, U.S.C. §119(e) of U.S. Provisional Patent Application Ser. No. 60/783,630, entitled METHODS OF PREDETERMINING THE CONTOUR OF A RESECTED BONE AND THE FIT OF AN IMPLANT ON THE BONE, filed Mar. 17, 2006, the disclosures of which are hereby expressly incorporated herein by reference.
BACKGROUNDThe present disclosure relates to methods for determining an optimal fit of a prosthesis on a resected bone surface.
Orthopaedic procedures for the replacement of all, or a portion of, a patient's joint typically require resecting and reshaping of the bones of the joint to receive prosthetic components. For example, a typical total knee prosthesis has three main components: a femoral component for replacing at least a portion of the distal end of the femur, a tibial component for replacing at least a portion of the proximal end of the tibia, and a bearing insert for replacing at least a portion of the articulating tissue between the femur and the tibia. Procedures for implanting a total knee prosthesis typically involve preparing and reshaping; both the distal end of the femur and the proximal end of the tibia prior to implanting the prosthetic components. The amount of bone removed may be partially determined by the size and type of prosthetic components to be implanted. The size of prosthetic components may be initially determined by measurements taken of the knee prior to and during surgery, and the final determination of size may be made after taking measurements and trialing a provisional prosthesis during the procedure.
SUMMARYThe present disclosure provides methods for predetermining a contour of a. resected bone surface and assessing a fit of a prosthesis on the resected hone surface. The present disclosure also provides methods for designing prostheses to tit discrete patient populations as well as methods for designing customized prostheses.
In one form thereof, the present disclosure provides a method of virtually assessing the fit of a prosthesis for placement on a resected bone surface, the method including the steps of creating a two-dimensional outline of the resected bone surface; creating a two-dimensional outline of a first prosthesis; and comparing the two-dimensional outline of the resected bone surface with the two-dimensional outline of the first prosthesis.
In another form thereof, the present disclosure provides an apparatus for virtually assessing the fit of a prosthesis for placement on a resected bone surface, the apparatus including a first computer adapted to create a two-dimensional outline of the resected bone surface; a second computer for creating a two-dimensional outline of a first prosthesis; and a third computer for comparing the two-dimensional outline of the resected bone surface with the two-dimensional outline of the first prosthesis.
In yet another firm thereof, the present disclosure pro-ides a method of designing a prosthesis to substantially fit a resected bone surface based on a population of bones, the method including the steps of creating a plurality of two-dimensional outlines corresponding to each resected bone surface for each bone of the population; and determining a contour of a bone engaging surface of a prosthesis using the plurality of two-dimensional outlines, wherein the contour substantially matches the plurality of two-dimensional outlines of the resected bone surfaces.
In still another form thereof, the present disclosure provides an apparatus for designing a prosthesis to substantially fit a resected bone surface based on a population of bones, the apparatus including a first computer for creating a plurality of two-dimensional outlines corresponding to each resected bone surface for each bone of the population; and a second computer for determining a contour of a bone engaging surface of a prosthesis which substantially matches the plurality of two-dimensional outlines of the resected bone surfaces.
In one form thereof, the present disclosure provides a method of creating a prosthesis for placement on a resected bone surface, the method including the steps of creating a two-dimensional outline of the resected bone surface; and determining a contour of a bone engaging surface of a prosthesis using the two-dimensional outline of the resected bone surface.
In another form thereof, the present disclosure provides an apparatus for creating a prosthesis for placement on a resected bone surface, the apparatus including a first computer for creating a two-dimensional outline of the resected bone surface; and a second computer for determining a contour of a. bone engaging surface of a prosthesis using the two-dimensional outline of the resected bone surface.
The above mentioned and other features of the disclosure, and the manner of attaining them, will become more apparent and will be better understood by reference to the following description of embodiments of the disclosure taken in conjunction with the accompanying drawings, wherein:
Corresponding reference characters indicate corresponding parts throughout the several views. Although the drawings represent embodiments of the present disclosure, the drawings are not necessarily to scale and certain features may be exaggerated in order to better illustrate and explain the present disclosure. Although the exemplifications set out herein illustrate embodiments of the disclosure, the embodiments disclosed below are not intended to be exhaustive or to be construed as limiting the scope of the invention to the precise forms disclosed.
DETAILED DESCRIPTIONThe present disclosure may include references to the following terms: anterior (at or near the front of the body, as opposed to the back of the body); posterior back of the body, as opposed to the front of the body); lateral (at or near the side of the body, farther from the midsagittal plane, as opposed to medial); medial (at or near the middle of the body, at or near the midsagittal plane, as opposed to lateral); proximal (toward the beginning, at or near the head of the body as opposed to distal); and distal(further from the beginning, at or near the foot of the body, as opposed to proximal).
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Prosthesis outline 26 may be visually compared with femur outline 18 to determine and assess whether model prosthesis 20 is a suitable fit for model femur 10. Thus, a surgeon may compare outline 26 with outline 18 and determine whether prosthesis 20 corresponding to outline 26 is an acceptable prosthesis to use for femur F. Prosthesis outline 26 may be compared with femur outline 18 by superimposing one atop the other and observing the overlapping shapes and the differences therebetween. Furthermore, using the suitable software mentioned. above, quantitative analysis may be made of outlines 26 and 18. For instance, measurements of outlines 26 and 18 may be taken and the suitable software can calculate deviations between the measurements. For example, width measurements of outlines 26 and 18 at the intersections of each planar surface may be taken and/or at midpoints of each planar surface between such intersections with other planar surfaces. Any deviations between outlines 26 and 18 may then be used to calculate proposed changes in prosthesis 20 to thereby reshape prosthesis 20 to minimize the deviations. Alternatively, any deviations between outlines 26 and 18 may prompt a user to select a different prosthesis 20 and perform the same analysis to assess the tit of the second prosthesis 20 on model femur 10, i.e., if a surgeon decides that outline 26 of a first prosthesis 20 is unacceptable for femur F, then the surgeon then compares the outline 26 of another prosthesis 20 until an acceptable prosthesis is identified.
The method described above has several useful, practical applications. For example, the method described above may be used to develop new and improved existing prosthesis designs. It is contemplated that this method may be used to survey a large population of subjects to develop statistics and identify trends in bone shapes, and to adapt prosthesis sizes and shapes accordingly. More specifically, two-dimensional footprints of virtually resected bones of a large population of patients may be obtained and compared to two-dimensional footprints of numerous available prostheses.
In an exemplary embodiment, a method of the present disclosure may be performed on the femurs of a large population of women to obtain medial/lateral and. anterior/posterior dimensions of the femurs and calculate ratios between the medial/lateral and anterior/posterior dimensions. These dimensions and calculations may be used in designing femoral components for use on female anatomy. In another exemplary embodiment, a method of the present disclosure may also be used to obtain medial/lateral and anterior/posterior dimensions of existing femoral components and calculate ratios between the medial/lateral and anterior/posterior dimensions of the femoral components. The dimensions and calculated ratios may then be used to compare existing femoral components to the dimensions and calculated ratios of the femurs of women to identify potential areas of the femoral component where fit can be optimized. Such a comparison is fully described in US. patent application Ser. No. 11/611,021, entitled DISTAL FEMORAL KNIFE PROSTHESES, assigned to the assignee of the present application the disclosure of which is hereby expressly incorporated herein by reference. The same type of process may be performed tor other populations, such as a population of males, various ethnic populations, populations based on age, stature-based populations, and/or populations based on disease progression or disease status.
In addition, the method described above may be used in guiding the design and manufacture of custom prostheses. For instance, a patient's femur may be modeled, virtually resected and footprinted as described above. The footprint could then be used as the footprint for forming a prosthesis.
Although the method described above is exemplified with reference to the distal end of the femur and femoral prostheses, the methods of the present invention may be applied to any bone and any prosthesis.
While this invention has been described as having exemplary designs, the present disclosure may be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the disclosure using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this disclosure pertains.
Claims
1. (canceled)
2. A system for virtually assessing the fit of a prosthesis for placement on a resected bone surface, the system comprising:
- a computer including at least one processor and a memory device, the memory device including instructions that, when executed by the at least one processor, cause the computer to: create a two-dimensional outline of the resected bone surface; create a plurality of two-dimensional outlines of a plurality of prostheses, each one of the two-dimensional outlines corresponding to one of the plurality of prostheses, each one of two-dimensional outlines derived from a contour of a bone engaging surface of the one of the plurality of prostheses; compare the two-dimensional outline of the resected bone surface with each two-dimensional outline of each the plurality of prostheses; and determine which one of the two-dimensional outlines of the plurality of prostheses comprises an acceptable match for the two-dimensional outline of the resected bone surface.
3. The system of claim 2, wherein the processor identifies a vertex between a first planar surface of the resected bone surface and a second planar surface of the resected bone surface based on a three-dimensional contour of the resected bone surface, and wherein the computer is configured to manipulate the first planar surface to be coplanar with the second planar surface and to outline a perimeter of the first planar surface and the second planar surface to define the two-dimensional outline of the resected bone surface.
4. The system of claim 3, wherein the computer is configured to repeat identifying and manipulating for each resected bone surface.
5. The system of claim 2, wherein the processor identifies a vertex between a first planar surface of the one of the plurality of prostheses and a second planar surface of the one of the plurality of prostheses based on a three-dimensional contour of the one of the plurality of prostheses, and wherein the computer is configured to manipulate the first planar surface to be coplanar with the second planar surface and to outline a perimeter of tile first planar surface and the second planar surface to define a two-dimensional outline of the one of the plurality of prostheses.
6. The system of claim 5, wherein the computer is configured to repeat identifying and manipulating for each planar surface of the one of the plurality of prostheses.
7. The system of claim 2, wherein to compare the two-dimensional outline of the resected bone surface with each two-dimensional outline of each the plurality of prostheses the computer superimposes the two-dimensional outline of the resected bone surface on each two-dimensional outlines of the plurality of prostheses.
8. A method of virtually assessing the fit of a prosthesis for implantation in a patient, the method comprising the steps of:
- resecting a virtual three-dimensional contour of a bone surface generated based on images of a joint of tile patient to obtain a virtual two-dimensional outline of a resected bone surface for the patient, the resecting including: creating one or more planar surfaces by flattening the virtual three-dimensional contour, and identifying a perimeter of the one or more planar surfaces;
- referencing a profile of a first prosthesis to create a virtual two-dimensional outline of the first prosthesis; and
- visually displaying the virtual two-dimensional outline of the resected bone surface with the virtual two-dimensional outline of the first prosthesis to allow for assessment of a fit of the first prosthesis with the resected bone surface.
9. The method of claim 8, wherein resecting includes:
- identifying a vertex between a first planar surface of the resected bone surface and a second planar surface of the resected bone surface,
- manipulating the first planar surface to be coplanar with the second planar surface, and
- outlining a perimeter of the first planar surface and the second planar surface to define the two-dimensional outline of the resected bone surface.
10. The method of claim 9, wherein the resected bone surface is defined by a plurality of intersecting cut planes, wherein the virtual two-dimensional outline of the resected bone surface includes the step of outlining the plurality of intersecting cut planes to obtain a three-dimensional profile of the resected bone surface, the two-dimensional outline of the resected bone surface being based on the virtual three-dimensional contour of the bone surface.
11. The method of claim 8, wherein referencing a profile of the first prosthesis to create a virtual two-dimensional outline of the first prosthesis includes:
- identifying a vertex between a first planar surface of the first prosthesis and a second planar surface of the first prosthesis based on a three-dimensional contour of the one of the plurality of prostheses; and
- wherein the computer is configured to manipulate the first planar surface to be coplanar with the second planar surface and to outline a perimeter of the first planar surface and the second planar surface to create the virtual two-dimensional outline of the first prosthesis.
12. The method of claim 8, visually displaying includes superimposing the two-dimensional outline of the resected bone surface on the virtual two-dimensional outline of the first prosthesis.
13. A method of virtually assessing the fit of a prosthesis for implantation in a patient, the method comprising the steps of:
- imaging a bone surface of a patient to obtain a virtual three-dimensional contour of the bone surface;
- obtaining a virtual two-dimensional outline of a resected bone surface for the patient, the obtaining including using a computer to flatten the virtual three dimensional contour to create one or more planar surfaces, and identify a perimeter of the one or more planar surfaces;
- obtaining a virtual two-dimensional outline of a first prosthesis from a profile of the first prosthesis, the profile identified virtually and based on a three-dimensional contour of a surface of the first prosthesis; and
- comparing the virtual two-dimensional outline of the resected bone surface with the virtual two-dimensional outline of the first prosthesis to access a fit of the first prosthesis with the resected bone surface.
14. The method of claim 13, wherein obtaining the virtual two-dimensional outline of a resected bone surface for the patient includes:
- identifying a vertex between a first planar surface of the resected bone surface and a second planar surface of the resected bone surface;
- manipulating the first planar surface to be coplanar with the second planar surface; and
- outlining a perimeter of the first planar surface and the second planar surface to define the two-dimensional outline of the resected bone surface.
15. The method of claim 14, wherein the resected bone surface is defined by a plurality of intersecting cut planes, wherein the virtual two-dimensional outline of the resected bone surface includes the step of outlining the plurality of intersecting cut planes to obtain a three-dimensional profile of the resected bone surface, the two-dimensional outline of the resected bone surface being based on the virtual three-dimensional contour of the bone surface.
16. The method of claim 13, wherein obtaining the virtual two-dimensional outline of the first prosthesis from the profile of the first prosthesis includes:
- identifying a vertex between a first planar surface of the first prosthesis and a second planar surface of the first prosthesis based on a three-dimensional contour of the one of the plurality of prostheses; and
- wherein the computer is configured to manipulate the first planar surface to be coplanar with the second planar surface and to outline a perimeter of the first planar surface and the second planar surface to create the virtual two-dimensional outline of the first prosthesis.
17. The method of claim 13, wherein comparing the virtual two-dimensional outline of the resected bone surface with the virtual two-dimensional outline of the first prosthesis includes superimposing the virtual two-dimensional outline of the resected bone surface on the virtual two-dimensional outline of the first prosthesis.
Type: Application
Filed: Oct 19, 2016
Publication Date: Feb 9, 2017
Inventors: Mohamed Mahfouz (Knoxville, TN), Brian D. Earl (South Bend, IN)
Application Number: 15/297,576