U.S. patent application number 15/208342 was filed with the patent office on 2017-04-06 for devices and methods for knee replacement.
The applicant listed for this patent is Bullseye Hip Replacement, LLC. Invention is credited to Benjamin A. Gillman, Michael Gillman.
Application Number | 20170095293 15/208342 |
Document ID | / |
Family ID | 54397012 |
Filed Date | 2017-04-06 |
United States Patent
Application |
20170095293 |
Kind Code |
A1 |
Gillman; Michael ; et
al. |
April 6, 2017 |
DEVICES AND METHODS FOR KNEE REPLACEMENT
Abstract
A device for use in joint replacement surgery is disclosed, the
device may comprise a patient-specific jig having a body formed
using three dimensional data corresponding to a first resection
surface of a bone of a patient according to a preoperative plan.
The body may also include a first bone facing surface configured to
match the first resection surface of the bone of the patient
according to the three dimensional data and an alignment perimeter
sized and shaped to match a perimeter of the resection surface of
the bone of the patient according to the three dimensional
data.
Inventors: |
Gillman; Michael; (Laguna
Beach, CA) ; Gillman; Benjamin A.; (Laguna Beach,
CA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Bullseye Hip Replacement, LLC |
Las Vegas |
NV |
US |
|
|
Family ID: |
54397012 |
Appl. No.: |
15/208342 |
Filed: |
July 12, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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14521031 |
Oct 22, 2014 |
9414846 |
|
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15208342 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 2017/568 20130101;
A61B 17/155 20130101; A61B 17/158 20130101; A61B 2034/108 20160201;
A61B 17/154 20130101; A61B 17/1767 20130101; G05B 19/4097 20130101;
A61B 34/10 20160201; A61B 2017/00526 20130101; G05B 2219/35012
20130101; A61B 17/1764 20130101; A61B 17/157 20130101 |
International
Class: |
A61B 34/10 20060101
A61B034/10; A61B 17/17 20060101 A61B017/17; G05B 19/4097 20060101
G05B019/4097; A61B 17/15 20060101 A61B017/15 |
Claims
1-20. (canceled)
21. A device for use in joint replacement surgery, the device
comprising: a jig having a shape corresponding to three dimensional
data of a shape of a first resected planar surface of a bone and a
shape of a second resected planar surface of the bone; the jig
including first and second bone facing planar surfaces, the first
bone facing planar surface shaped to match the shape of the first
resected planar surface and the second bone facing planar surface
shaped to match the shape of the second resected planar surface; at
least a portion of an outer perimeter of the patient-specific jig
surrounding the first and second bone facing planar surfaces sized
and shaped to match three dimensional data of a shape of a
non-resected perimeter of the resected planar surfaces of the bone;
and a plurality of alignment members extending from the outer
perimeter, the plurality of alignment members configured to mate
with a respective portion of three dimensional data of non-resected
bone adjacent the non-resected perimeter.
22. The device for use in joint replacement surgery of claim 21,
further comprising: guide holes passing through the jig, the guide
holes having an opening at the first bone facing planar surface and
positioned and shaped according to a preoperative plan and a final
installation position of a prosthesis.
23. The device for use in joint replacement surgery of claim 2
wherein: the guide holes include guide surfaces orientated
according to the preoperative plan and the final installation
position of the prosthesis.
24. The device for use in joint replacement surgery of claim 1,
further comprising: the first bone facing planar surface having a
first edge and the second bone facing surface having a second edge,
the first bone facing planar surface and second bone facing surface
having different orientations and meeting at the first and second
edges.
25. The device for use in joint replacement surgery of claim 21,
wherein: each of the plurality of alignment members configured to
align with a respective one of a plurality of points of bone
adjacent the resected planar surface according to the three
dimensional data of the bone structure of the patient.
26. The device for use in joint replacement surgery of claim 21
wherein the jig is configured to be positioned against a resected
planar surface of a femur.
27. The device for use in joint replacement surgery of claim 21
wherein the jig is configured to be positioned against a resected
planar surface of a tibia.
28. The device for use in joint replacement surgery of claim 21
wherein the jig is configured to be positioned against a resected
planar surface of a patella.
29. The device for use in joint replacement surgery of claim 26
wherein the jig includes a guide surface adjacent the posterior of
an intercondylar fossa of the three dimensional data of the bone
structure of the patient, the guide surface orientated to guide
removal of a portion of the intercondylar fossa of the patient
according to the preoperative plan.
30. A method of fabricating a device for use in joint replacement
surgery, the method comprising: generating, by a computer
processor, a bone surface image from three dimensional data of the
bone; generating, by a computer processor, a bone resection image
based on an installation position of a prosthesis relative to the
bone surface image, the bone resection image including a perimeter
of a first resection surface of the bone surface image; generating,
by a computer processor, a jig image proximate the bone resection
image, the jig image depicting a device according to claim 21; and
generating, by a computer processor, machine control data from the
jig image such that the machine control data is capable of use in
forming the device of claim 21.
31. The method for use in joint replacement surgery of claim 30,
further comprising: generating a prosthesis image in an
installation position superimposed on the bone surface image before
the generating the bone resection image.
32. The method for use in joint replacement surgery of claim 30
wherein generating a bone resection image includes generating a
bone surface image of at least a portion of a femur.
33. The method for use in joint replacement surgery of claim 30
wherein generating a bone resection image includes generating a
bone surface image of at least a portion of a tibia.
34. The method for use in joint replacement surgery of claim 32
wherein generating a bone resection image includes generating a
bone surface image of at least a portion of a tibia.
35. The method for use in joint replacement surgery of claim 34
wherein generating a bone resection image includes generating a
bone surface image of at least a portion of a patella.
36. The method for use in joint replacement surgery of claim 30,
further comprising: generating, by a computer processor, guide
holes passing through the jig image, the guide holes having an
opening at the first bone facing planar surface and positioned and
shaped according to a preoperative plan and the installation
position of the prosthesis.
37. The method for use in joint replacement surgery of claim 31,
wherein: the guide holes include guide surfaces orientated
according to the preoperative plan and the final installation
position of the prosthesis.
38. The method for use in joint replacement surgery of claim 30,
wherein: the first bone facing planar surface has a first edge and
the second bone facing surface has a second edge, the first bone
facing planar surface and second bone facing surface having
different orientations and meeting at the first and second
edges.
39. The method for use in joint replacement surgery of claim 30,
wherein: each of the plurality of alignment members is configured
to align with a respective one of a plurality of points of bone
adjacent the resected planar surface according to the three
dimensional data of the bone structure of the patient.
40. The method for use in joint replacement surgery of claim 32
wherein: the jig image includes a guide surface adjacent the
posterior of an intercondylar fossa of the three dimensional data
of the bone structure of the patient, the guide surface orientated
to guide removal of a portion of the intercondylar fossa of the
patient according to the preoperative plan.
Description
BACKGROUND
[0001] Technical Field
[0002] The present disclosure relates to devices and methods for
the replacement of joints, and more particularly, to
patient-specific knee replacement devices, including methods of
manufacturing and using such devices for achieving accurate
resection of patient bones and accurate placement of prosthetics
based on computer generated imaging of a patient.
[0003] Background of the Invention
[0004] One known method of treating knee and other joints with
arthritis and other medical conditions is to replace surfaces of
articulating joints with prosthetic devices through surgical
procedures. It is critical that such prosthetic devices are
accurately designed and manufactured and that they are installed
correctly so that they relieve pain and provide an effective
treatment method for such ailments. An orthopedic surgeon
performing such joint replacement on a patient seeks to ensure,
through surgery, adequate placement of the prosthetic and proper
reconstruction of the joint being replaced. A particular patient's
bone structure symmetry is one important consideration that a
surgeon must consider when performing joint replacement surgery.
Additionally, malposition of joint replacement prosthetics can
result in untoward pain or premature wear of the bearing surfaces,
which may require additional surgeries to correct. Improperly sized
prosthetic components that are tool large or too small may also
cause pain, loosening of prostheses or accelerated wear. Repairing
improperly sized prosthetic components may require additional
surgeries.
[0005] In the case of a knee, the condition of the patient's joint
may require a partial or total replacement. A partial knee
replacement may involve removing the joint surfaces of one or more
of the femur, tibia, or patella bones in the medial, lateral, or
patellofemoral compartments. A partial knee replacement may include
replacing one or more surfaces of the upper tibia, the shin bone,
and the lower femur, including the articular surface, the medial
condyle, or the lateral condyle. A partial knee replacement may
also include removing and replacing the inner or underside surface
of the patella, also called the knee cap. A total knee replacement
typically involves removal and replacement of the lower surface or
distal portion of the femur, including the medial and lateral
condyles; replacement of the upper surface or proximal portion of
the tibia, including the medial and lateral condyles; and
replacement of the inner or underside surface of the patella.
[0006] In total knee replacement, the removed bone and anatomy is
typically replaced with a prosthesis. The removed parts of the
femur are replaced with a femoral component, the removed parts of
the tibia are replaced with a tibial component, and the surface of
the patella is replaced with a patellar component. A polymer spacer
is usually placed between the femoral and tibial components as an
articulating surface to facilitate smooth movement between the
surfaces of the components.
[0007] One concern during the bone removal stage of a knee
replacement surgery is that the surgeon may not make the correct
cuts to the bones which may result in malaligned prosthesis and a
poorly functioning knee replacement. Therefore, accurate removal
and resurfacing of the knee bones is an important part of a knee
replacement surgery. Surgeons may use cutting guides and cutting
blocks to assist in the cutting or sectioning of the knee
bones.
[0008] Another concern is that a surgeon may place a final
prosthetic that is either too small or too large for a patient's
bone. Both improper bone cuts and improper sized implants may lead
to untoward pain, early wear, or early loosening of prostheses that
may result in a secondary unnecessary surgery.
[0009] With the assistance of computer generated data derived from
CT, MRI, or other scans, such as X-rays, surgeons can more
effectively determine proper alignment and positioning of the knee
prosthetics in a patient through 3D modeling and rendering. Some
surgeons use guides or generic extramedullary or intramedullary
cutting guides during surgery in an attempt to properly place the
prosthetics; however, accuracy and simplicity of existing devices
and methods remain limited due to a variety of factors.
BRIEF SUMMARY
[0010] A device for use in joint replacement surgery is disclosed,
the device may comprise a patient-specific jig having a body formed
using three dimensional data corresponding to a first resection
surface of a bone of a patient according to a preoperative plan.
The body may also include a first bone facing surface configured to
match the first resection surface of the bone of the patient
according to the three dimensional data and an alignment perimeter
sized and shaped to match a perimeter of the resection surface of
the bone of the patient according to the three dimensional
data.
[0011] A method for use in joint replacement surgery is disclosed.
The method may include generating a bone surface image from three
dimensional image data from the bone structure of a patient. The
method may also include generating a bone resection image based on
a final installation position of a prosthesis and the three
dimensional image data from the bone structure of a patient and
generating a patient specific resection jig image superimposed
proximate the bone resection image. Machine control data from the
patient specific resection jig image may also be generated.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0012] FIG. 1 depicts a method according to one or more embodiments
disclosed herein;
[0013] FIG. 2 depicts a system according to one or more embodiments
disclosed herein;
[0014] FIG. 3 depicts a method according to one or more embodiments
disclosed herein;
[0015] FIG. 4 depicts a knee joint and the bones associated
therewith;
[0016] FIG. 5 depicts a sectioned femur and a sectioned tibia
according on one or more embodiments disclosed herein;
[0017] FIG. 6 depicts a sectioned patella according on one or more
embodiments disclosed herein;
[0018] FIG. 7 depicts patient-specific jigs for knee replacement
installed on the bones of the knee according to one or more
embodiments disclosed herein;
[0019] FIG. 8 depicts a patient-specific patella jig installed
according to one or more embodiments disclosed herein;
[0020] FIG. 9 depicts a sectioned knee bones according to one or
more embodiments disclosed herein;
[0021] FIG. 10 depicts patient-specific jigs for knee replacement
according to one or more embodiments disclosed herein;
[0022] FIG. 11 depicts sectioned knee bones and patient-specific
jigs according to one or more embodiments disclosed herein;
[0023] FIG. 12 depicts sectioned knee bones according to one or
more embodiments disclosed herein.
DETAILED DESCRIPTION
[0024] The present disclosure pertains to patient-specific knee
replacement devices and methods of designing, manufacturing, and
using such devices for achieving accurate component or prosthesis
sizing and placement during knee replacement surgery based on
computer generated imaging of a particular patient. When an
orthopedic surgeon recommends knee replacement surgery for a
particular patient, a variety of images may be obtained utilizing
CT, MRI, and other scans, such as x-rays, to generate 3D modeling
of the patient's bone structure, particularly the femur, the tibia,
and then patella. From such 3D models, the surgeon may determine
the specific, final size, geometry, location, and orientation of
the femoral component, tibial component, and patellar components to
be secured to the patient's bones during surgery. Surgeons may
select the prosthetics from a number of standard sizes and shapes
or may use patient-specific prosthetics.
[0025] Once the final size, geometry, location, and orientation of
the prosthetics are determined, the surgeon may create one or more
patient-specific jigs to be installed on the patient's knee bones
during the surgery to confirm accurate removal and preparation of
the patient's bones. The patient-specific jigs may also include
features such as guide holes or apertures for guiding additional
bone preparation procedures. These patient-specific jigs may
conform to the shape of a properly prepared bone such that, during
surgery, if the jig does not properly engage with the prepared bone
structure of the patient, the surgeon knows that additional primary
bone preparation may be necessary to prepare the bones for accurate
placement of the prosthetics in the patient.
[0026] A femoral patient-specific jig may be designed and
manufactured based on a patient-specific distal femur end. The
patient-specific jig can be developed as either physical components
via a prototyping machine or visual representations in a 3D
modeling software program based upon the 3D images of the
patient.
[0027] The methods and systems disclosed herein are based at least
in part on pre-operating (pre-operative) imaging and at least in
part on orthopedic surgical procedures based upon the pre-operative
methods and systems. As is understood in the art, pre-operative
imaging has a number of different purposes and generally is
performed to help guide the surgeon during the surgical procedure,
allow for patient-specific tools, or implants to be formed, and
etc. The present disclosure may be part of a system for designing
and constructing one or more patient-specific jigs for use in an
orthopedic surgical procedure in which knee replacement components
are prepared, orientated, and implanted. The referenced systems and
methods are now described with reference to the accompanying
drawings, in which one or more illustrated embodiments or
arrangements of the systems and methods are shown in accordance to
one or more embodiments disclosed herein. Aspects of the present
systems and methods can take the form of an entirely hardware
embodiment, an entirely software embodiment (including firmware,
resident software, micro-code, etc.), or an embodiment combining
software and hardware. One of skill in the art can appreciate that
a software process can be transformed into an equivalent hardware
structure, and a hardware structure can itself be transformed into
an equivalent software process. Thus, the selection of a hardware
implementation versus a software implementation is one of design
choice and left to the implementer.
[0028] FIG. 1 is a flow diagram illustrating a method pertaining to
pre-operative imaging and planning according to aspects of the
present disclosure. FIG. 2 shows a system for carrying out the
methods of the present disclosure, such as that described with
reference to FIG. 1. FIG. 2 shows a simplified system 210 of
devices that may be used to carry out the methods of the present
disclosure. The system 210 comprises a computing system 212 coupled
to an imaging system 214. The imaging system 214 captures patient
image data and transfers the data to the computing system 212. The
computing system 212 processes such data and transmits the data to
a display device 216 for display of images and other data. An input
device 218 receives input from a computer or an operator (such as a
surgeon) and transmits inputted information to the computing system
212 for processing. Such input devices 218 are well known in the
art and will not be described in greater detail. The imaging system
214 may include a bone imaging machine for forming
three-dimensional image data from a bone structure of a patient.
The computing system 212 may include a patient-specific device
generator for processing and generating images, and a
patient-specific device converter for generating design control
data. A manufacturing machine 220 receives the control data from
the computing system 212 for making patient-specific jigs.
[0029] In FIG. 1, a method 100 according to an embodiment may start
at block 102. At block 102, a bone imaging machine generates a bone
surface image from three-dimensional image data from the bone
structure, such as the bones of the knee, of a patient. The bone
surface image may include at least a portion of one or more of the
femur, patella, tibia, and fibula. At block 104, a patient-specific
device generator generates one or more prosthesis images
superimposed on the bone surface image. The prosthesis image is
positioned in its final, implanted position and orientation,
regardless of the state of the patient's bone in the bone surface
image. A mating surface of the prosthesis image may determine the
surface of the resectioned knee bones of the patient. For example,
by placing the prosthesis image in the final, implanted position
and orientation, a surgeon may determine the final shape and
orientation of the resectioned knee bone, for example, the femur,
such that a prosthesis may be installed on the patient's
resectioned femur in the correct, final, implanted position and
orientation. The jigs created from the present disclosure may be
designed to confirm proper resectioning of the knee bones during a
knee replacement procedure.
[0030] At block 106, the patient-specific device generator
generates a bone resection image. The bone resection image may
include images of the bone surfaces on which a prosthesis is
installed. The resection image may be generated according to the
installation position of the prosthesis.
[0031] At block 108, the patient-specific device generator
generates a patient-specific jig image superimposed proximate the
bone resection image and the bone surface image. The
patient-specific device generator may use the bone surface image
and bone resection image to create a patient-specific device with
anatomic engagement members that have an engagement surface that
corresponds to, matches, or is the negative contour of the
patient's anatomy.
[0032] At block 110, a patient-specific device converter generates
control data from the patient-specific jig image. The control data
may be in the form of a machine readable file, such as a g-code
file, for controlling a manufacturing machine. The control data may
be used by a machine during a manufacturing process to create
physical patient-specific jigs by additive or subtractive
machining, such as fused deposition modeling, stereolithography, or
other methods. At block 112, the manufacturing device creates a
physical patient-specific jig.
[0033] As discussed above, FIG. 2 shows one embodiment of the
system 210 for carrying out the methods of FIG. 1 according to some
aspects of the present disclosure. The computing system 212 may
include instructions in the form of computer software for
automatically generating images of prosthesis implants in final
installation positions and patient-specific jigs on the bone
structure images. In some aspects, it may be necessary for the
surgeon during preoperative planning to input information into the
input device 218 for creating or altering jig images or prostheses
images for a particular patient based on the surgeon's
understanding of the particular bone structure of the patient as
displayed on the display device 216.
[0034] FIG. 3 is a flow diagram of a method pertaining to operative
surgery according to aspects of the present disclosure. The method
of FIG. 3 may be carried out by a surgeon, by a machine, or by
both. Moreover, the process may utilize some or all of the devices
discussed with reference to FIGS. 1 and 2 during surgery, such as
viewing the preoperative images displayed on the display device
while operating on a patient.
[0035] FIG. 3 shows a method 300 according to an embodiment
disclosed herein. The method 300 may be carried out using a
patient-specific jigs, such as, for example, the patient-specific
jigs shown in FIGS. 7, 8, 10, and 11. The method may start at block
302 with the resectioning of the knee bone. In full or total knee
replacement procedures patients have their femur, tibia, and
patella bones resectioned to accept a prosthetic. The resection
process may include cutting, milling or any other method to prepare
the surface of the bones to accept a prosthetic.
[0036] At block 304, a surgeon or machine may place a
patient-specific resection jig adjacent the bone of the joint of
the patient, the patient-specific resection jig formed according to
a resection image of the bone of the patient and three-dimensional
image data from the bone structure of a patient. Placing the
patient-specific resection jig may include aligning an alignment
surface with a resectioned surface of the bone or aligning an
anatomic alignment member of the patient-specific jig to a
corresponding preselected area adjacent or peripheral the
resectioned bone portion of the patient. For example, a surgeon may
position the patient-specific resection jig on the resectioned
surface of the patient's bone and align, but possibly not engage,
the various alignment members of the patient-specific resection jig
with anatomical features adjacent the resectioned surfaces of a
patient. The surgeon may also attempt to align the bone facing
surfaces and a periphery of the patient-specific resection jig with
the resection surface of the patient's bone and periphery thereof.
By positioning the jig in such a manner, the surgeon may evaluate
the initial resection cuts and determine whether adjustments should
be made to the initial resection cuts before attempting to drill or
otherwise create the prosthesis mounting holes or placing the
prosthesis in its final or predetermined installation position. If
the patient specific jig is too large or too small, the surgeon may
confirm that too little or too much bone has been removed or that
the previous cuts were made improperly.
[0037] At block 306, a surgeon or machine may attempt to engage an
anatomical alignment member of the patient-specific jig
corresponding to preselected areas adjacent to or on the periphery
of the resectioned surface of the bone of the patient. At block
308, a surgeon or machine may determine whether the alignment
members are engaged with the preselected contact points adjacent or
peripheral the resectioned bone of the joint of the patient. The
surgeon or a machine may also determine whether the bone facing
surfaces and periphery of the patient-specific resection jig are
engaged with or aligned with the resectioned surface of the bone of
the patient and the periphery thereof. If the patient-specific
resection jig is properly aligned and engaged with the bone, then
the surgeon or machine may determine that the resection portion of
the surgery is complete and may use the patient-specific jig as a
guide for accurately conducting additional or final machining of
the bone prior to placing a prosthesis. If the patient-specific
resection jig is not properly aligned or engaged with the bone, the
surgeon or machine may evaluate the misalignment or disengagement
and determine how to adjust or account for the improperly
resectioned bone surfaces. For example, a misalignment of one side
of the patient-specific resection jig may indicate that the
resection was cut at an incorrect angle. As an additional example,
a patient specific jig that has a perimeter larger or smaller than
the perimeter of a resection surface of the bone may convey that
too littler or too much bone was removed and allow for a surgeon to
consider changing the intraoperative plan.
[0038] In some embodiments, a surgeon may remove additional bone
with a saw or other device and revise the initial bone cuts by
cutting more bone. In other instances, a surgeon may accept the
suboptimal bone cut or cuts and place additional bone cement in the
area, augment the prosthesis to correct for the incorrect cut, or
otherwise proceed to complete the planned surgical procedure.
[0039] If the resection was incorrectly performed and the
patient-specific resection jig does not align or engage properly
with the patient's bone, then the decision at block 308 may proceed
to block 310.
[0040] At block 310, the patient-specific resection jig is removed
from the bone of the joint of the patient. Here, the surgeon or a
machine may remove the jig from the patient and proceed to block
312.
[0041] At block 312, the surgeon or a machine may modify the
resection of the bone of the joint of the patient. In full or total
knee replacement procedures a surgeon may perform additional bone
removal or resection procedures on the femur, tibia, or patella
bones to correct the previous resection attempts. The additional
resection process may include cutting, milling or any other method
to prepare the surface of the bones to accept a prosthetic. The
actions performed at block 312 may be similar to the actions
performed early at block 302. These actions may include, for
example, positioning a resection guide at the patient's joint to
aid in performing the resection or bone removal procedures.
[0042] The method may then proceed back to block 306, as shown in
FIG. 3, where a surgeon or machine may again attempt to engage an
anatomical alignment member of the patient-specific jig
corresponding to preselected areas adjacent to or on the periphery
of the resectioned surface of the bone of the patient. In some
embodiments, the method may proceed from block 312 back to block
304 where the surgeon or machine may again place a patient-specific
resection jig adjacent the bone of the joint of the patient, the
patient-specific resection jig formed according to a resection
image of the bone of the patient and three-dimensional image data
from the bone structure of a patient before proceeding again to
block 306 and eventually to block 308.
[0043] At block 308, the surgeon or machine evaluates the resection
and preparation of the bone for receiving a prosthesis. The
alignment and engagement of the patient-specific resection jig is
evaluated. If the alignment members of the patient-specific
resection jig engage with the preselected contact points or areas
adjacent or peripheral the bone of the joint of the patient, then
the procedure may proceed to block 314.
[0044] At block 314, a surgeon or machine conducts additional bone
and joint preparation actions. In some embodiments, a
patient-specific resection jig may include guide holes for creating
lug holes in a patient's bone, such as the femur, for mounting a
prosthetic, guides or guide surfaces to assist in cutting the
intercondylar notch area of the femur for posterior cruciate
substituting knee replacement techniques, and guide holes for
creating a cavity for receiving a stem of the tibial prosthesis.
The surgeon or machine may use drills, mills, saws, broaches, or
other tools when undertaking the additional preparatory actions at
block 314.
[0045] At block 316, a surgeon or machine installs the prosthesis.
One or more prostheses may be installed, including a femoral
prosthesis, tibular prosthesis, or patellar prosthesis.
[0046] FIG. 4 shows a knee joint 400 and the bones associated with
the knee joint. The knee joint includes four bones, the femur 410,
the tibia 440, the fibula 490, and the patella 475. In knees most
partial and full knee replacement surgeries of one or more of the
femur 410, the tibia 440 and the patella 475 are modified while the
fibula is usually not directly modified during the surgery. The
lower or distal end of the femur 410 includes lateral (outer)
femoral condyle 422 and medial (inner) femoral condyle 420. The
femoral condyle 420, 422 are weight bearing projections that ride
on the meniscus, not shown, of the knee. The meniscus is located
between the lower end of the femur 410 and the upper end of the
tibia 440 and acts to reduce friction in and load on the knee. The
intercondylar fossa 435 is the depression at the end of the femur
410 between the femoral condyle 420, 422. The posterior cruciate
ligament (PCL) and the anterior cruciate ligament (ACL), not shown,
attach to the femur 410 in the intercondylar fossa 435. The femur
also includes the patellar groove or surface 436. The patellar
groove 436 is located on the front of the femur 410 and behind the
patella 475. The patella 475 rides in the patellar groove 436 as
the knee joint 400 bends and straightens.
[0047] The tibia 440 includes a medial tibia condyle 460 and a
lateral tibia condyle 462. The tibia condyles 460, 462 bear the
forces imparted by the corresponding femoral condyles 420, 422. The
tibia 440 also includes an intercondylar eminence 466, located
between the tibia condyles 460, 462. The ACL and PCL attach to the
tibia 440 in front of and behind the intercondylar eminence
466.
[0048] FIG. 5 shows a resectioned knee joint 400 with the patella
omitted for clarity. FIG. 5 shows an example of what a knee may
typically look like after the initial resectioning of the femur 410
and tibia 440 according to a preoperative plan by either
traditional techniques using extramedullary or intramedullary
guides or other known techniques. This is how a knee may look, for
example, after the resection procedure at block 302 of the method
300. The femur 410 and tibia 440 show a resection according to a
total knee replacement where the patient has their femur, tibia,
and patella bones resectioned to accept a prosthetic. The resection
process may include cutting, milling or any other method to prepare
the surface of the bones to accept a prosthetic.
[0049] The femur 410 includes five resectioned surfaces, the
anterior resectioned surface 424, anterior-distal resectioned
surface 425, the distal resectioned surface 426, the
posterior-distal resectioned surface 427, and the posterior
resectioned surface 428. Each resectioned surface 424, 425, 426,
427, 428 is bounded by an edge. For example, a perimeter 429
delineates the boundary between the resectioned surfaces 424, 425,
426, 427, 428 and the unmodified bone of the femur, while vertices
430, 431, 432, 433 form the edges between adjacent resectioned
surfaces 424, 425, 426, 427, 428. The posterior portion of the
intercondylar fossa 435 is also visible in this view.
[0050] Although depicted at having five resectioned surfaces, in
some embodiment the femur 410 may have more than five resectioned
surfaces or less than five resectioned surfaces.
[0051] During the resectioning of the femur 410 in a total knee
replacement, a surgeon or machine removes at least a portion of,
and in many cases all of the medial condyle 420, lateral femoral
condyle 422, the patellar groove 436, and the intercondylar fossa
435 to prepare the femur 410 to accept a femoral prosthesis or
implant. In a partial knee replacement, a smaller portion of the
femur 410 is removed, for example, only the medial or lateral
condyle of the lower end of the femur 410 is resectioned.
[0052] While resectioning the femur may involve a number or cuts to
create several resectioned surfaces 424, 425, 426, 427, 428, the
tibia 440 may only include a single resectioned surface 470
surrounded by a perimeter 472 to accept a tibia prosthesis or
implant. The resectioning of the tibia 440 for total knee
replacement may include removing the upper surface of the tibia
440, including the medial tibia condyle 460, the lateral tibia
condyle 462, and the intercondylar eminence 466. In a partial knee
replacement, a smaller portion of the tibia 440 is removed. For
example, only the medial or lateral half of the upper end of the
tibia 440 is resectioned.
[0053] FIG. 6 shows the posterior view of the patella 475 after
resection. The resectioned surface 476 of the patella 475 is
surrounded by an edge 477 between the resectioned surface 476 of
the bone and the unmodified portion of the patella 475. Although
depicted as substantially round, in some embodiments the shape of
the resectioned surface 476 of the patella 475 is not round.
Indeed, the shape of the resectioned surface 476 of the patella 475
differs from patient to patient, as does the resectioned surfaces
of the femur 410 and tibia 440.
[0054] After the surgeon or machine resections the bones a surgeon
may insert a patient-specific resection jig into the patient. A
patient-specific resection jig, such as the patient-specific
femoral resection jig 600 shown in FIG. 7 may be designed and
manufactured based on a patient femur 410 and the preoperatively
planned resection surfaces 424, 425, 426, 427, 428 made to the
femur 410. The patient-specific femoral resection jig 600 aids in
verifying the resection cuts made to the femur 410 and in preparing
the femur 410 to accept a prostheses in PCL preserving knee
replacement procedures. The patient-specific femoral resection jig
600 can be developed as either a physical component via a
prototyping machine or visual representations in a 3D modeling
software program based upon the 3D images of the patient.
[0055] The patient-specific femoral resection jig 600 includes a
body that is shaped to conform to the shape of the resectioned
femur 410. For example, the body of the patient-specific femoral
resection jig 600 includes a bone facing side 640 that includes one
or more bone facing surfaces 641, 642, 643, 644, 645. Each of the
bone facing surfaces 641, 642, 643, 644, 645 are shaped to match a
corresponding resection surface 424, 425, 426, 427, 428, based on
the preoperative planning. If the surgeon performed the resection
procedure correctly, as determined by the preoperative plan, then
each of the bone facing surfaces 641, 642, 643, 644, 645 should
match or contact the corresponding resection surface. For example,
the first bone facing surface 641 should match or contact the
resection surface 424. One or more of the bone facing surfaces 641,
642, 643, 644, 645 may have an orientation or angle different than
the orientation or angle of another bone facing surface 641, 642,
643, 644, 645.
[0056] If the surgeon performed the resection procedure and did not
make the resection cuts in accordance with the preoperative plan,
then the bone facing surfaces 641, 642, 643, 644, 645 may not match
the corresponding resection surfaces 424, 425, 426, 427, 428 or
there may be a size mismatch between the bone facing surfaces of
the patient-specific jig and the and the patient's resectioned
bone. When this happens, the patient-specific femoral resection jig
600 may indicate information to the surgeon regarding the resection
surfaces. For example, if the resection cut for the first resection
surface 424 did not remove enough of the femur 410, then the bone
facing surfaces 641 may contact the first resection surface 424,
but this contact may prevent the other bone facing surfaces 642,
643, 644, 645 from contacting or otherwise aligning with their
corresponding resection surfaces 425, 426, 427, 428.
[0057] Similarly, if the resection cut for the first resection
surface 424 removed too much of the femur 410, then the bone facing
surfaces 641 may not contact the first resection surface 424,
while, if the rest of the resection cuts were correctly made, then
the other bone facing surfaces 642, 643, 644, 645 may still contact
or otherwise align with their corresponding resection surfaces 425,
426, 427, 428.
[0058] The patient-specific femoral resection jig 600 may also
include a perimeter alignment feature, such as the alignment
perimeter 610. As shown in FIG. 5, the resectioned surfaces 424,
425, 426, 427, 428 are bounded by a perimeter 429. The perimeter
429 is created during the resectioning process and may be
determined during preoperative planning based on the patient's
particular bone geometry and the location, depth, and orientation
of each of the resection surfaces that the surgeon plans to make to
the femur 410.
[0059] The shape of the alignment perimeter 610 may also be
determined during preoperative planning. The shape of the alignment
perimeter 610 matches the shape of the perimeter 429 of a properly
resectioned femur 410 according to the preoperative plan. During a
knee replacement procedure, a surgeon or machine may place the
patient-specific femoral resection jig 600 against the femur 410
and attempt to align the alignment perimeter 610 with the perimeter
429 of the resectioned surfaces 424, 425, 426, 427, 428. If the
alignment perimeter 610 does not align with the perimeter 429 of
the resectioned surfaces 424, 425, 426, 427, 428, then the surgeon
knows that they may need to perform remedial work on the
resectioned surfaces 424, 425, 426, 427, 428, or otherwise account
for the resectioned surfaces 424, 425, 426, 427, 428 not matching
the preoperative plan.
[0060] In some embodiments, the surgeon may perform additional
resection cuts on the femur 410 to correct the resection surfaces
so that the surfaces match the preoperative plan. To help the
surgeon, the position and misalignment of the alignment perimeter
610 may indicate information to the surgeon or machine regarding
the resectioned surfaces 424, 425, 426, 427, 428. For example, if
the alignment perimeter 610 is outside the perimeter 429 of the
resectioned surfaces 424, 425, 426, 427, 428, then the surgeon or
machine may determine that the resection cut removed too much bone
and the surgeon or machine may determine that shims should be added
to the prosthesis to account for the excess bone removal. If the
alignment perimeter 610 is inside the perimeter 429 of the
resectioned surfaces 424, 425, 426, 427, 428, the surgeon or
machine may determine that the resection cut removed too little
bone and the surgeon or machine may determine that additional
resection cuts should be made to the femur 410.
[0061] The patient-specific femoral resection jig 600 may also
include one or more alignment members, such as the alignment
members 620 extending from a periphery of the body of the
patient-specific femoral resection jig 600. The alignment members
620 include an alignment surface 622 that conforms or matches the
anatomic surface structure of the bone of the patient. For example,
one or more alignment members 620 may align or engage with a point
or area on the distal end of the femur 410 or adjacent the
resection surface according to the three dimensional data of the
bone structure of the patient. The alignment surface 622 may
include a surface shape or contours that match the surface shape or
contours of the anatomic structure with which the alignment member
620 aligns.
[0062] The shape and contours of the alignment surface 622 may be
determined based upon the 3-D modeling images of the patient, a
combination of two-dimensional radiographic images of the patient,
or a combination of three-dimensional and two-dimensional images of
a patient. The shape of the alignment surface 622 may also be
referred to as a negative of the anatomic structure with which the
alignment surface 622 aligns or engages. It is a negative because,
for example, a protrusion on the distal end of the femur 410 would
correspond to a depression on the alignment surface 622 while a
depression on the distal end of the femur 410 would correspond to a
protrusion on the alignment surface 622. Although depicted as
having four alignment members, each with a single alignment
surface, in some embodiments, a patient-specific femoral resection
jig may have more or less than four alignment members and each may
have more than one alignment surface. In some embodiments, a
patient-specific femoral resection jig may have no alignment
members.
[0063] The alignment members 620 and the alignment surfaces 622 may
also provide information to the surgeon regarding the resection of
the bone of the patient. For example, the alignment members 620 and
the alignment surfaces 622 provide information to the surgeon
regarding whether the bone has been properly or improperly
resectioned. For example if any one of the alignment members 620 or
the alignment surfaces 622 associated with the alignment members
620 is not making contact with the patient's bone, the surgeon may
decide to perform a different resection, reposition the
patient-specific femoral resection jig 600, or accept the
imperfection and proceed with further surgery.
[0064] In PCL preserving knee replacement procedures, the
patient-specific femoral resection jig 600 may include guides for
creating features for mounting a prosthesis to the femur 410. For
example, the patient-specific femoral resection jig 600 includes
guide holes 630. The guide holes 630 are positioned and shaped
according to the preoperative plan and the final installation
position of the prosthesis and aid in guiding a surgical tool for
creating mounting holes or cavities.
[0065] In addition to being in the correct position and shape for
the proper placement of the mounting holes or cavities, the guides
may include a surface guide to aid in creating the cavity or hole
at the correct angle. For example, if the surface guides 631 are
perpendicular to the resectioned surface 643, then they can guide a
tool in a perpendicular direction into the femur 410 to create the
cavity or hole. By using guides that have other angles with respect
to the resectioned surface, a surgeon or machine can create
cavities or holes at other angles.
[0066] FIG. 7 also depicts a patient-specific tibia resection jig
700 designed and manufactured based on a patient tibia 440 and the
preoperatively planned resection surface 470 made to the tibia 440.
The patient-specific tibia resection jig 700 aids in verifying the
resection cut made to the tibia 440 and in preparing the tibia 440
to accept a prostheses. The patient-specific tibia resection jig
700 can be developed as either a physical component via a
prototyping machine or as visual representations in a 3D modeling
software program based upon the 3D images of the patient.
[0067] The patient-specific tibia resection jig 700 includes a body
that is shaped to conform to the shape of the resectioned tibia
440. For example, the body of the patient-specific tibia resection
jig 700 includes a bone facing side defined by at least one bone
facing surface 720. The bone facing surface 720 is shaped to match
a corresponding resection surface 470 of the tibia 440 based on the
preoperative plan. Although the patient-specific tibia resection
jig 700 shown in FIG. 7 includes a single bone facing surface 720,
in some embodiments, the body of the patient-specific tibia
resection jig 700 may contain more than one bone facing surface
720. If the surgeon performed the resection procedure correctly,
then the bone facing surface 720 should match or contact the
corresponding resection surface 470.
[0068] If the surgeon performed the resection procedure and did not
make the resection cut in accordance with the preoperative plan,
then the bone facing surface 720 may not match the corresponding
resection surface 470. When this happens, the patient-specific
tibia resection jig 700 may indicate information to the surgeon
regarding the resection surfaces. For example, if the resection cut
for the resection surface 470 is not flat or in a single plane,
then the bone facing surface 720 may contact a portion of the
resection surface 470, but not contact other portions of the of the
resection surface 470. In such a situation, the patient-specific
tibia resection jig 700 may indicate to the surgeon the locations
on the resection surface 470 of the tibia 440 where additional bone
material should be removed such that the resection surface 470 may
match the surface prescribed in the preoperative plan.
[0069] The patient-specific tibia resection jig 700 may also
include a perimeter alignment feature, such as the alignment
perimeter 710. The resectioned surface 470 is bounded by a
perimeter 472. The perimeter 472 is created during the resectioning
process and may be determined during preoperative planning based on
the patient's particular bone geometry and the location, depth, and
orientation of the resection surface 470 of the tibia 440.
[0070] The shape of the alignment perimeter 710 may also be
determined during preoperative planning. The shape of the alignment
perimeter 710 matches the shape of the perimeter 472 of a properly
resectioned tibia 440 according to the preoperative plan. During a
knee replacement procedure, a surgeon or machine may place the
patient-specific tibia resection jig 700 against the tibia 440 and
attempt to align the alignment perimeter 710 with the perimeter 472
of the resectioned surface 470. If the alignment perimeter 710 does
not align with the perimeter 472 of the resectioned surface 470,
then the surgeon knows that they may need to perform additional
remedial work on the resectioned surface 470, or to otherwise
account for the resectioned surfaces 470 not matching the
preoperative plan.
[0071] In some embodiments, the surgeon may perform additional
resection cuts on the tibia 440 to correct the resection surface
470 so that the surface matches the preoperative plan. To help the
surgeon, the position and misalignment of the alignment perimeter
710 may indicate information to the surgeon or machine regarding
the resectioned surface 470. For example, if the alignment
perimeter 710 is inside the perimeter 472 of the resectioned
surface 470, then the surgeon or machine may determine that the
resection cut removed an inadequate amount of bone and more bone
may need to be removed. If the alignment perimeter 710 is outside
the perimeter 472 of the resectioned surface 470, then the surgeon
or machine may determine that too much bone was resected and the
surgeon or machine may use an augmented prosthesis, additional
cement, determine that additional resection cuts should be made, or
use other methods to make accommodations for the incorrect
resection.
[0072] The alignment perimeter 710 may also indicate that the
resection surface 470 was cut at an incorrect angle. For example, a
portion of the alignment perimeter 710 on a first side of the
patient-specific tibia resection jig 700 may align with the outside
the perimeter 472 of the resectioned surface 470, but a second side
of the patient-specific tibia resection jig 700 may not align with
the outside the perimeter 472 of the resectioned surface 470. This
type of partial alignment may indicate that the resection of the
tibia 440 was performed at an angle other than that prescribed in
the preoperative plan.
[0073] The patient-specific tibia resection jig 700 may also
include one or more alignment members, such as the alignment
members 730 extending from a periphery of the body of the
patient-specific tibia resection jig 700. The alignment members 730
include an alignment surface 732 that conforms or matches the
anatomic surface structure of the bone of the patient. For example,
one or more alignment members 730 may align or engage with a point
or area on the proximal end of the tibia 440 or adjacent the
resection surface to the three dimensional data of the bone
structure of the patient. The alignment surface 732 may include a
surface shape or contours that match the surface shape or contours
of the anatomic structure with which the alignment member 730
aligns.
[0074] The shape and contours of the alignment surface 732 may be
determined based upon the 3-D modeling images of the patient, a
combination of two-dimensional radiographic images of the patient,
or a combination of three-dimensional and two-dimensional images of
a patient. The shape of the alignment surface 732 may also be
referred to as a negative of the anatomic structure with which the
alignment surface 732 aligns or engages.
[0075] The alignment members 730 and the alignment surfaces 732 may
also provide information to the surgeon regarding the resection of
the bone of the patient. For example, the alignment members 730 and
the alignment surfaces 732 provide information to the surgeon
regarding whether the bone has been properly or improperly
resectioned. For example if any one of the alignment members 730 or
the alignment surfaces 732 associated with the alignment members
730 is not making contact with the patient's bone, the surgeon may
decide to perform a different resection, reposition the
patient-specific tibia resection jig 700, or accept the
imperfection and proceed with further surgery.
[0076] Although depicted as having four alignment members, each
with a single alignment surface, in some embodiments, the
patient-specific tibia resection jig 700 may have more or less than
four alignment members 730 and each may have more than one
alignment surface 732. In some embodiments, the patient-specific
tibia resection jig 700 may have no alignment members 730.
[0077] The patient-specific tibia resection jig 700 may include
guides for creating features for mounting a prosthesis to the tibia
440. For example, the patient-specific tibia resection jig 700
includes guide hole 740. The guide hole 740 is positioned and
shaped according to the preoperative plan and aids in guiding a
surgical tool for creating mounting holes or cavities for attaching
the tibial component to the tibia 440 in a final installation
position. The guide hole 740 may include a primary guide 744 and
secondary guides 742, 746. The primary guide 744 may aid in guiding
a tool for creating a hole or cavity for receiving the main body of
the tibial component's mounting stem while the secondary guides
742, 746 aid in creating a hole or cavity for receiving the
stabilizing extension members of the tibial component.
[0078] In addition to being in the correct position and shape for
the proper placement of the mounting holes of cavities, the guides
may include a surface guide to aid in creating the cavity or hole
at the correct angle. For example, if the surface guide 747 is
perpendicular to the resectioned surface 470, then the surface
guide 747 can guide a tool in a perpendicular direction into the
tibia 440 to create the cavity or hole. By using guides that have
other angles with respect to the resectioned surface, a surgeon or
machine can create cavities or holes at other angles.
[0079] FIG. 8 depicts a patient-specific patella resection jig 800
designed and manufactured based on a patient patella 475 and the
preoperatively planned resection surface 476 made to the patella
475. The patient-specific patella resection jig 800 aids in
verifying the resection cut made to the patella 475 and in
preparing the patella 475 to accept a prostheses. The
patient-specific patella resection jig 800 can be developed as
either a physical component via a prototyping machine or as visual
representations in a 3D modeling software program based upon the 3D
images of the patient.
[0080] The patient-specific patella resection jig 800 includes a
body 840 that is shaped to conform to the shape of the resectioned
patella 475. For example, the body 840 of the patient-specific
patella resection jig 800 includes a bone facing side defined by at
least one bone facing surface 830. The bone facing surface 830 is
shaped to match a corresponding resection surface 476 of the
patella 475 based on the preoperative plan. Although the
patient-specific patella resection jig 800 shown in FIG. 8 includes
a single bone facing surface 830, in some embodiments, the body 840
of the patient-specific patella resection jig 800 may contain more
than one bone facing surface 830. If the surgeon performed the
resection procedure correctly, then the bone facing surface 830
should match or contact the corresponding resection surface
476.
[0081] As with the tibia and femur resection procedures and jigs,
if the surgeon performed the resection procedure and did not make
the resection cut in accordance with the preoperative plan, then
the bone facing surface 830 of the patient-specific resection jig
800 may not match the corresponding resection surface 476 of the
patella 475. When this happens, the patient-specific patella
resection jig 800 may indicate information to the surgeon regarding
the resection surface. For example, if the resection cut for the
resection surface 476 is not flat or in a single plane, then the
bone facing surface 830 may contact a portion of the resection
surface 476, but not contact other portions of the resection
surface 476. In such a situation, the patient-specific patella
resection jig 800 may indicate to the surgeon the locations on the
resection surface 476 of the patella 475 where additional bone
material should be removed such that the resection surface 476 may
match the surface prescribed in the preoperative plan or where
additional cement may be used to compensate for an incorrect
resection.
[0082] The patient-specific patella resection jig 800 may also
include a perimeter alignment feature, such as the alignment
perimeter 850. The resectioned surface 476 is bounded by a
perimeter 477. The perimeter 477 is created during the resectioning
process and may be determined during preoperative planning based on
the patient's particular bone geometry and the location, depth, and
orientation of the resection surface 476 of the patella 475.
[0083] The shape of the alignment perimeter 850 may also be
determined during preoperative planning. The shape of the alignment
perimeter 850 matches the shape of the perimeter 477 of a properly
resectioned patella 475 according to the preoperative plan. During
a knee replacement procedure, a surgeon or machine may place the
patient-specific patella resection jig 800 against the patella 475
and attempt to align the alignment perimeter 850 with the perimeter
477 of the resectioned surface 476. If the alignment perimeter 850
does not align with the perimeter 477 of the resectioned surface
476, then the surgeon knows that they may need additional remedial
work on the resectioned surface 476, or to otherwise account for
the resectioned surface 476 not matching the preoperative plan, for
example, as described above with respect to the femur 410 and tibia
440. A size mismatch of the patella jig to the cut patella may
indicate that either too much bone or not enough bone has been
removed.
[0084] The patient-specific patella resection jig 800 may also
include one or more alignment members, such as the alignment
members 820 extending from a periphery of the body of the
patient-specific patella resection jig 800. The alignment members
820 include an alignment surface 822 that conforms or matches the
anatomic surface structure of the bone of the patient. For example,
one or more alignment members 820 may align or engage with a point
or area adjacent to the resection surface 476 of the patella 475 to
the three dimensional data of the bone structure of the patient.
The alignment surface 822 may include a surface shape or contours
that match the surface shape or contours of the anatomic structure
with which the alignment member 820 aligns.
[0085] The alignment members 820 and the alignment surfaces 822 may
also provide information to the surgeon regarding the resection of
the bone of the patient. For example, the alignment members 820 and
the alignment surfaces 822 provide information to the surgeon
regarding whether the bone has been properly or improperly
resectioned. For example if any one of the alignment members 820 or
the alignment surfaces 822 associated with the alignment members
820 is not making contact with the patient's bone, the surgeon may
decide to perform a different resection, reposition the
patient-specific patella resection jig 800, or accept the
imperfection and proceed with further surgery.
[0086] The shape and contours of the alignment surface 822 may be
determined based upon the 3-D modeling images of the patient, a
combination of two-dimensional radiographic images of the patient,
or a combination of three-dimensional and two-dimensional images of
a patient. The shape of the alignment surface 822 may also be
referred to as a negative of the anatomic structure with which the
alignment surface 822 aligns or engages.
[0087] Although depicted as having three alignment members 820,
each with a single alignment surface, in some embodiments, the
patient-specific patella resection jig 800 may have more or less
than three alignment members 820 and each may have more than one
alignment surface 822. In some embodiments, the patient-specific
patella resection jig 800 may have no alignment members 820.
[0088] The patient-specific patella resection jig 800 may include
guides for creating features for mounting a prosthesis to the
patella 475. For example, the patient-specific patella resection
jig 800 includes three guide holes 810. The guide holes 810 are
positioned and shaped according to the preoperative plan and aid in
guiding a surgical tool for creating mounting holes or cavities for
attaching the patella component to the patella 475 according to the
preoperative plan. In some embodiments, the patient-specific
patella resection jig 800 may include more or fewer guide holes
810. Various surgical tools may be used to further machine the
patella for acceptance of a final prosthesis or prior to placing a
final prosthesis.
[0089] In addition to being in the correct position and shape for
the proper placement of the mounting holes or cavities, the guides
may include a guiding surface 812 to aid in creating the cavity or
hole at the correct angle. For example, if the guiding surface 812
is perpendicular to the resectioned surface 476, then the guiding
surface 812 can guide a tool in a perpendicular direction into the
patella 475 to create the cavity or hole. By using guides that have
other angles with respect to the resectioned surface, a surgeon or
machine can create cavities or holes at other angles.
[0090] FIG. 9 depicts an embodiment of a knee joint 400 after
resectioning the ends of the femur 410 and tibia 440, creating the
mounting cavities 412, 414, 442 for the femoral and tibia
components in a PCL preserving knee replacement procedure. As shown
in FIG. 9, the posterior portion of intercondylar fossa 435 remains
intact which preserves PCL attachment to the femur 410. FIG. 9
shows how the femur 410 and the tibia 440 would look during a knee
replacement procedure before installation of the femoral and tibia
components.
[0091] The patient-specific femoral resection jig 900, shown as
engaged with the femur 907 of the knee joint 905 in FIG. 10, is an
embodiment of a jig used in PCL sacrificing knee replacement
procedures. The patient-specific femoral resection jig 900 aids in
verifying the resection cut made to the femur 907 and in preparing
the femur 907 to accept a prostheses. The patient-specific femoral
resection jig 900 can be developed as either a physical component
via a prototyping machine or as visual representations in a 3D
modeling software program based upon the 3D images of the
patient.
[0092] The patient-specific removal resection jig 900 includes a
body that is shaped to conform to the shape of the resectioned
femur 907. For example, the body of the patient-specific removal
resection jig 900 includes a bone facing side defined by at least
one bone facing surface 940. The bone facing surface 940 is shaped
to match a corresponding resection surface of the femur 907 based
on the preoperative plan. If the surgeon performed the resection
procedure correctly, the bone facing surface 940 should match or
contact the corresponding resection surface.
[0093] If the surgeon performed the resection procedure and did not
make the resection cut in accordance with the preoperative plan,
the bone facing surface 940 of the patient-specific femoral
resection jig 900 may not match the corresponding resection surface
of the femur 907. When this happens, the patient-specific femoral
resection jig 900 may indicate information to the surgeon regarding
the resection surface. For example, the patient-specific femoral
resection jig 900 may indicate to the surgeon the locations on the
resection surface of the femur 907 where bone material should be
removed such that the resection surface may match the surface
prescribed in the preoperative plan. In some embodiments, the
patient-specific femoral resection jig 900 may indicate that too
little or too much bone was removed during resection or that the
resection cut was made at an incorrect angle. By attempting to
align the bone facing surface 940 with the resectioned surface of
the femur 907, the patient-specific femoral resection jig 900 may
indicate to the surgeon how the surface was missectioned and may
aid the surgeon in determining appropriate corrective actions to
fix or account for the incorrectly sectioned femur 907. In some
embodiments, the surgeon may accept the imperfection and proceed
with surgery. In some embodiments, the surgeon may augment the
prosthesis or add additional cement to account for the
imperfection, or in some embodiments proceed in another manner.
[0094] The patient-specific femoral resection jig 900 may also
include a perimeter alignment feature, such as the alignment
perimeter 910. The resectioned surface of the femur 907 is bounded
by a perimeter 908. The perimeter 908 is created during the
resectioning process and may be determined during preoperative
planning based on the patient's particular bone geometry and the
location, depth, and orientation of the resection surface of the
femur 907.
[0095] The shape of the alignment perimeter 910 may also be
determined during preoperative planning. The shape of the alignment
perimeter 910 matches the shape of the perimeter 908 of a properly
resectioned femur bone 907 according to the preoperative plan.
During a knee replacement procedure, a surgeon or machine may place
the patient-specific femur resection jig 900 against the femur 907
and attempt to align the alignment perimeter 910 with the perimeter
908 of the resectioned femur 907. If the alignment perimeter 910
does not align with the perimeter 908 of the resectioned femur 907,
the surgeon knows that they may need to perform remedial work on
the resectioned surface, or to otherwise account for the
resectioned surface not matching the preoperative plan.
[0096] The patient-specific femur resection jig 900 may also
include one or more alignment members, such as the alignment
members 920 extending from a periphery of the body of the
patient-specific femoral resection jig 900. The alignment members
920 include an alignment surface 922 that conforms to or matches
the anatomic surface structure of the bone of the patient. For
example, one or more alignment members 920 may align or engage with
a point or area adjacent to the resection surface of the femur 907
to the three dimensional data of the bone structure of the patient.
The alignment surface 922 may include a surface shape or contours
that match the surface shape or contours of the anatomic structure
with which the alignment member 920 aligns.
[0097] The shape and contours of the alignment surface 922 may be
determined based upon the 3-D modeling images of the patient, a
combination of two-dimensional radiographic images of the patient,
or a combination of three-dimensional and two-dimensional images of
a patient. The shape of the alignment surface 922 may also be
referred to as a negative of the anatomic structure with which the
alignment surface 922 aligns or engages.
[0098] Although depicted as having four alignment members 920, each
with a single alignment surface, in some embodiments, the
patient-specific femoral resection jig 900 may have more or less
than four alignment members 920 and each may have more than one
alignment surface 922. In some embodiments, the patient-specific
femoral resection jig 900 may have no alignment members 920.
[0099] The patient-specific femoral resection jig 900 may include
guides for creating features for mounting a prosthesis to the femur
907 or for removing the posterior portion of the intercondylar
fossa 935. For example, the patient-specific femoral resection jig
900 includes an intercondylar fossa removal guide 950 with at least
one intercondylar fossa removal guide surface 952. The guide
surface 952 is positioned and shaped according to the preoperative
plan and aids in guiding a surgical tool for removing the posterior
portion of the intercondylar fossa 935. During the knee replacement
procedure, a surgeon may guide a cutting blade or tool using the
intercondylar fossa removal guide 950 and intercondylar fossa
removal guide surface 952.
[0100] FIG. 11 depicts an embodiment of a knee joint 905 and femur
907 after the removal of the posterior of the intercondylar fossa.
The notch 936 created by the removal of the posterior of the
intercondylar fossa using the guide surface 952 is shown. In the
depicted embodiment, the surface 937 of the notch 936 aligns with
the guide surface 952 because the surgeon used the guide surface
952 when removing the posterior of the intercondylar fossa form the
femur 907.
[0101] FIG. 12 shows the knee joint 905, after a successful
resection of the femur 907 and the tibia 909 and creation of the
notch 936 and mounting cavity 442 in a knee replacement performed
using the posterior cruciate ligament substituting/sacrificing
technique. As shown, the femur 907 and the tibia 909 are prepared
to accept a femoral component and tibia component.
[0102] The various embodiments described above can be combined to
provide further embodiments. All of the U.S. patents, U.S. patent
application publications, U.S. patent applications, foreign
patents, foreign patent applications and non-patent publications
referred to in this specification and/or listed in the Application
Data Sheet are incorporated herein by reference, in their entirety.
Aspects of the embodiments can be modified, if necessary to employ
concepts of the various patents, applications and publications to
provide yet further embodiments.
[0103] These and other changes can be made to the embodiments in
light of the above-detailed description. In general, in the
following claims, the terms used should not be construed to limit
the claims to the specific embodiments disclosed in the
specification and the claims, but should be construed to include
all possible embodiments along with the full scope of equivalents
to which such claims are entitled. Accordingly, the claims are not
limited by the disclosure.
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