WO2013177675A1

WO2013177675A1 - Post-manufacturing inspection of machined object

Info

Publication number: WO2013177675A1
Application number: PCT/CA2013/000521
Authority: WO
Inventors: Florent Miquel; Philippe MYRAND-LAPOINTE; Jean Robichaud; Gabriel ROBICHAUD
Original assignee: Laboratoires Bodycad Inc.
Priority date: 2012-05-29
Filing date: 2013-05-29
Publication date: 2013-12-05

Abstract

There is provided a system and method for manufacturing and inspecting a machined object having an object surface adapted to matingly engage an articular surface of a bone. A digital representation of the bone comprising a virtual articular surface representative of the articular surface is received. A digital representation of the machined object comprising a virtual object surface representative of the object surface is received. The virtual object surface is coupled to the virtual articular surface. The machined object is approved if the coupled virtual object surface and virtual articular surface are matingly engaged. Physical testing of the machined object comprises machining the digital representation of the bone into a machined bone comprising a machined articular surface representative of the articular surface. The object surface if coupled to the machined articular surface and the machined object is approved if the coupled object surface and machined surface are matingly engaged.

Description

POST-MANUFACTURING INSPECTION OF MACHINED OBJECT

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This patent application claims priority of US provisional Application Serial No. 61/652,425, filed on May 29, 2012.

TECHNICAL FIELD

[0002] The present invention relates to the field of computer-aided machining and more particularly, to methods for post-manufacturing inspection of a machined object.

BACKGROUND OF THE ART

[0003] Prostheses may be used to replace missing body parts or repair damaged articular joints. Each patient's anatomy being different, it may be desirable to design patient-specific prostheses, which are adapted to fit each patient's unique anatomical features, thus increasing the outcome of the surgery procedure.

[0004] For this purpose, prosthetic components are usually pre-operatively designed and once machined surgically implanted in the patient's body on the basis of the pre-operative planning. Despite such planning, prosthetic components may be implanted in a less than optimal biomechanical position relative to the patient's anatomy. As a result, pain may be caused to the patient and premature wear or even failure of the prosthetic components may occur.

[0005] There is therefore a need for improved methods for inspecting an object, such as a prosthesis, following a manufacturing thereof.

SUMMARY

[0006] In accordance with the present application, there is provided a computer- implemented method for inspecting a machined object having a first object surface adapted to matingly engage a first articular surface of a first bone, the method comprising executing on a processor program code for receiving a first digital bone representation, the first digital bone representation a digital representation of the first bone and comprising a first virtual articular surface representative of the first articular surface, receiving a digital object representation, the digital object representation a digital representation of the machined object and comprising a first virtual object surface representative of the first object surface, coupling the first virtual object surface to the first virtual articular surface, approving the machined object if the coupled first virtual object surface and first virtual articular surface are matingly engaged, and rejecting the machined object otherwise.

[0007] Still further in accordance with the present application, subsequent to rejecting the machined object, receiving correction data indicative of at least one correction to be applied to at least one parameter of an original design of the machined object to generate a modified design to be used for creating a new machined object.

[0008] Still further in accordance with the present application, receiving a design value of at least one first dimension, the design value defined in an original design of the machined object, measuring the at least one first dimension in the digital object representation, comparing the measured at least one first dimension to the design value, and approving the machined object if the measured at least one first dimension is within a first predetermined tolerance of the design value.

[0009] Still further in accordance with the present application, measuring at least one second dimension of the digital object representation, measuring the at least one second dimension of the first digital bone representation, comparing the measured at least one second dimension of the digital object representation to the measured at least one second dimension of the first digital bone representation, and approving the machined object if the measured at least one second dimension of the first digital bone representation is within a second predetermined tolerance of the measured at least one second dimension of the digital object representation. [0010] Still further in accordance with the present application, the at least one first dimension and the at least one second dimension are selected from the group consisting of a length, a width, and a curvature.

[0011] Still further in accordance with the present application, measuring at least one third dimension indicative of a position of the digital object representation relative to the first digital bone representation, comparing the measured at least one third dimension to a threshold, and approving the machined object if the at least one third dimension is below the threshold.

[0012] Still further in accordance with the present application, measuring the at least one third dimension comprises measuring a spacing between the first virtual object surface and the first virtual articular surface.

[0013] Still further in accordance with the present application, receiving the first digital bone representation comprises receiving at least one anatomical direction of the first bone and further wherein measuring the at least one third dimension comprises measuring an alignment of the digital object representation relative to the at least one anatomical direction.

[0014] Still further in accordance with the present application, receiving the digital object representation comprises receiving a digital representation of at least one attachment means provided with the machined object, the at least one attachment means adapted to be received in at least one aperture formed in the first bone for retaining the machined object in place relative to the first bone, and receiving the first digital bone representation comprises receiving a digital representation of the at least one aperture, and further comprising approving the machined object if the digital representation of the at least one fixation is received in the digital representation of the at least one aperture when the first virtual object surface is coupled to the first virtual articular surface.

[0015] Still further in accordance with the present application, the received digital object representation comprises a second virtual object surface representative of a second object surface opposite the first object surface, and further comprising receiving a second digital bone representation, the second digital bone representation a digital representation of a second bone and comprising a second virtual articular surface representative of a second articular surface of the second bone, the second articular surface adapted to matingly engage the second object surface, coupling the second virtual object surface to the second virtual articular surface, approving the machined object if the coupled second virtual object surface and second virtual articular surface are matingly engaged, and rejecting the machined object otherwise.

[0016] Still further in accordance with the present application, positioning, with the second virtual object surface coupled to the second virtual articular surface, the digital representation of the machined object at an angle relative to the at least one anatomical direction and approving the machined object if the coupled second virtual object surface and second virtual articular surface are matingly engaged with the digital representation of the machined object so positioned.

[0017] Still further in accordance with the present application, receiving the digital object representation comprises receiving a digital representation of a machined object created using patient-specific modeling.

[0018] Further in accordance with the present application, there is provided a system for inspecting a machined object having a first object surface adapted to matingly engage a first articular surface of a first bone, the system comprising a memory, a processor, and at least one application stored in the memory and executable by the processor for receiving a first digital bone representation, the first digital bone representation a digital representation of the first bone and comprising a first virtual articular surface representative of the first articular surface, receiving a digital object representation, the digital object representation a digital representation of the machined object and comprising a first virtual object surface representative of the first object surface, coupling the first virtual object surface to the first virtual articular surface, approving the machined object if the first coupled virtual object surface and first virtual articular surface are matingly engaged, and rejecting the machined object otherwise.

[0019] Still further in accordance with the present application, the at least one application is executable by the processor for receiving, subsequent to rejecting the machined object, correction data indicative of at least one correction to be applied to at least one parameter of an original design of the machined object to generate a modified design to be used for creating a new machined object.

[0020] Still further in accordance with the present application, the at least one application is executable by the processor for receiving a design value of at least one first dimension, the design value defined in an original design of the machined object, measuring the at least one first dimension in the digital object representation, comparing the measured at least one first dimension to the design value, and approving the machined object if the measured at least one first dimension is within a first predetermined tolerance of the design value.

[0021] Still further in accordance with the present application, the at least one application is executable by the processor for measuring at least one second dimension of the digital object representation, measuring the at least one second dimension of the first digital bone representation, comparing the measured at least one second dimension of the digital object representation to the measured at least one second dimension of the first digital bone representation, and approving the machined object if the measured at least one second dimension of the first digital bone representation is within a second predetermined tolerance of the measured at least one second dimension of the digital object representation.

[0022] Still further in accordance with the present application, the at least one application is executable by the processor for measuring at least one third dimension indicative of a position of the digital object representation relative to the first digital bone representation, comparing the measured at least one third dimension to a threshold, and approving the machined object if the at least one third dimension is below the threshold.

[0023] Still further in accordance with the present application, the at least one application is executable by the processor for measuring the at least one third dimension comprising measuring a spacing between the first virtual object surface and the first virtual articular surface. [0024] Still further in accordance with the present application, the at least one application is executable by the processor for receiving the first digital bone representation comprising receiving at least one anatomical direction of the first bone and further wherein the at least one application is executable by the processor for measuring the at least one third dimension comprising measuring an alignment of the digital object representation relative to the at least one anatomical direction.

[0025] Still further in accordance with the present application, the at least one application is executable by the processor for receiving the digital object representation comprising receiving a digital representation of at least one attachment means provided with the machined object, the at least one attachment means adapted to be received in at least one aperture formed in the first bone for retaining the machined object in place relative to the first bone, for receiving the first digital bone representation comprising receiving a digital representation of the at least one aperture, and for approving the machined object if the digital representation of the at least one fixation is received in the digital representation of the at least one aperture when the first virtual object surface is coupled to the first virtual articular surface.

[0026] Still further in accordance with the present application, the at least one application is executable by the processor for receiving the digital object representation comprising a second virtual object surface representative of a second object surface opposite the first object surface, for receiving a second digital bone representation, the second digital bone representation a digital representation of a second bone and comprising a second virtual articular surface representative of a second articular surface of the second bone, the second articular surface adapted to matingly engage the second object surface, for coupling the second virtual object surface to the second virtual articular surface, for approving the machined object if the coupled second virtual object surface and second virtual articular surface are matingly engaged, and for rejecting the machined object otherwise. [0027] Still further in accordance with the present application, the at least one application is executable by the processor for positioning, with the second virtual object surface coupled to the second virtual articular surface, the digital representation of the machined object at an angle relative to the at least one anatomical direction and for approving the machined object if the coupled second virtual object surface and second virtual articular surface are matingly engaged with the digital representation of the machined object so positioned.

[0028] Further in accordance with the present application, there is provided a method for inspecting a machined object having a first object surface adapted to matingly engage a first articular surface of a first bone, the method comprising receiving a first digital bone representation, the first digital bone representation a digital representation of the first bone and comprising a first virtual articular surface representative of the first articular surface, and at least one of virtually inspecting the object, the virtual inspection comprising receiving a digital object representation, the digital object representation a digital representation of the machined object and comprising a first virtual object surface representative of the first object surface, coupling the first virtual object surface to the first virtual articular surface, approving the machined object if the coupled first virtual object surface and first virtual articular surface are matingly engaged, and rejecting the machined object otherwise, and physically inspecting the object, the physical inspection comprising machining the first digital bone representation into a first machined bone comprising a first machined articular surface representative of the first articular surface, coupling the first object surface to the first machined articular surface, approving the machined object if the coupled first object surface and first machined articular surface are matingly engaged; and rejecting the machined object otherwise.

[0029] Still further in accordance with the present application, the received digital object representation comprises a second virtual object surface representative of a second object surface opposite the first object surface, and further comprising receiving a second digital bone representation, the second digital bone representation a digital representation of a second bone and comprising a second virtual articular surface representative of a second articular surface of the second bone, the second articular surface adapted to matingly engage the second object surface.

[0030] Still further in accordance with the present application, virtually inspecting the object comprises coupling the second virtual object surface to the second virtual articular surface, approving the machined object if the coupled second virtual object surface and second virtual articular surface are matingly engaged, and rejecting the machined object otherwise and physically inspecting the object comprises machining the second digital bone representation into a second machined bone comprising a second machined articular surface representative of the second articular surface, coupling the second object surface to the second machined articular surface, approving the machined object if the coupled second object surface and second machined articular surface are matingly engaged, and rejecting the machined object otherwise.

[0031] Further in accordance with the present application, there is provided a computer readable medium having stored thereon program code executable by a processor for inspecting a machined object having a first object surface adapted to matingly engage a first articular surface of a first bone, the program code executable for receiving a first digital bone representation, the first digital bone representation a digital representation of the first bone, and comprising a first virtual articular surface representative of the first articular surface, receiving a digital object representation, the digital object representation a digital representation of the machined object and comprising a first virtual object surface representative of the first object surface, coupling the first virtual object surface to the first virtual articular surface, approving the machined object if the coupled first virtual object surface and first virtual articular surface are matingly engaged, and rejecting the machined object otherwise.

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Further features and advantages of the present invention will become apparent from the following detailed description, taken in combination with the appended drawings, in which: [0033] Figure 1 a is a flowchart of a method for manufacturing a prosthesis and inspecting the machined prosthesis post-fabrication, in accordance with an illustrative embodiment of the present invention;

[0034] Figure 1 b is a flowchart of the manufacturing step of Figure a;

[0035] Figure 1 c is a flowchart of the testing step of Figure 1 a;

[0036] Figure 1d is a flowchart of the virtual testing step of Figure 1 c;

[0037] Figure 1 e is a flowchart of the physical testing step of Figure 1 c;

[0038] Figure 2 is a schematic diagram of a computer system for manufacturing a prosthesis and inspecting the machined prosthesis post-fabrication, in accordance with an illustrative embodiment of the present invention;

[0039] Figure 3a is a schematic diagram of an application running on the processor of Figure 2;

[0040] Figure 3b is a schematic diagram of the prosthesis design module of Figure 3a;

[0041] Figure 3c is a schematic diagram of the prosthesis validation module of Figure 3a;

[0042] Figure 4a is a screen capture of a user interface for virtually testing a machined prosthesis post-fabrication, in accordance with a first illustrative embodiment of the present invention;

[0043] Figure 4b is a screen capture of a user interface for virtually testing the attachment of the prosthesis of Figure 4a to a bone;

[0044] Figure 4c is a screen capture of a user interface for virtually testing the mating of the surface of the prosthesis of Figure 4a with an articular bone surface; and [0045] Figure 5 is a perspective view of a prosthesis physically tested on a machined bone model, in accordance with a first illustrative embodiment of the present invention.

[0046] It will be noted that throughout the appended drawings, like features are identified by like reference numerals.

DETAILED DESCRIPTION

[0047] Referring to Figure 1a, a computer-aided method 100 for manufacturing a patient-specific object and inspecting the manufactured object post-fabrication will now be described. It should be understood that, although the description below refers to the manufacturing of a patient-specific prosthesis, other patient- specific objects, such as cutting blocks, surgical tools, or the like, which may interact or be mated with the patient's anatomical structures during a surgical procedure, may apply.

[0048] The method 100 comprises obtaining at step 102 images of anatomical structures, which refers to acquiring image data of the anatomical region of the patient's body where the prosthesis is to be implanted. Such anatomical region may for example comprise the hip, knee, and ankle regions when total knee replacement surgery is concerned. Although the method 100 is described herein with reference to a knee, it should be understood that the method 100 may apply to other articular joints, such as an elbow, shoulder, wrist, or hip. It should also be understood that the method may apply to prostheses other than articular joint repair prostheses.

[0049] The images may be obtained from scans generated using Magnetic Resonance Imaging (MRI), Computed Tomography (CT), ultrasound, x-ray technology, optical coherence tomography, or the like. Such images may be provided by a user, such as a medical technician, a surgeon, or a treating physician, via a suitable communication means to a computer system (not shown) adapted to process the method 100. For this purpose, the user may electronically provide the scans of the patient's anatomy to the computer system via electronic mail, a Picture Archiving and Communication System (PACS) server, a website, or the like. The captured images may further be provided in various known formats, such as Digital Imaging and Communications in Medicine (DICOM), for handling, storing, printing, and transmitting information via PACS. Other exemplary formats are GE SIGNA Horizon LX, Siemens Magnatom Vision, SMIS MRD/SUR, and GE MR SIGNA 3/5 formats.

[0050] Once the images of the patient's anatomy have been obtained at step 102, they may be processed and segmented at step 104. Indeed, as images may be acquired along one or more planes throughout the body part, such as sagittal, coronal, and transverse, as well as multiple orientations, the data may be combined or merged during processing. Image segmentation may further be performed in order to extract from the images information related to the patient's damaged knee joint, such as the mechanical leg axis or the size of the tibial plateau and femoral head. A virtual two-dimensional (2D) representation of the damaged knee joint may then be created from the segmented images. A virtual three dimensional (3D) bone model of the patient's damaged knee joint may also be provided. The selection of the type of bone model to be generated, namely 2D or 3D, is illustratively made according to user preferences, such as technical capabilities associated with a device the user employs to interact with the computer system.

[0051] Using such a virtual 3D bone model as well as additional design parameters and patient-related information, which may be provided by the user, a patient-specific prosthesis adapted to fit the patient's unique anatomy may be virtually designed at step 106 using patient-specific modeling. Using such modeling, the patient-specific prosthesis (or other suitable patient-specific object) can be created so as to comprise one or more surfaces adapted to interact or be precisely mated with one or more surfaces of the patient's unique anatomical structures. The patient-related information may comprise a name, age, weight, and gender of the patient. The design parameters may comprise the manner, in which the mechanical leg axis may be computed. The mechanical axis refers to the angle formed between a line drawn from the center of the femoral head to the medial tibial spine and a line drawn from the medial tibial spine and the center of the ankle joint. It is desirable to specify the mechanical axis, and more particularly the reference points to be used for computation thereof, as proper geometric alignment of prosthesis components relative to the mechanical axis affects prosthesis performance. Misalignment may indeed result in undesirable wear and even failure of the prosthesis.

[0052] Other design parameters may comprise, but are not limited to, total varus/valgus alignment, minimum knee flexion, and minimum knee extension, which may be specified in degrees. Moreover, parameters related to the prosthesis type, such as the material, model, shape, surface rugosity, and attachment mechanism thereof may be provided. For example, unicomparmental or bilateral prostheses may be used. Also, the prosthesis material may comprise any material suitable for biocompatibility, such as a metal alloy, titanium, medical grade stainless steel, tantalum, cobalt-chrome, and ceramics. Although parameters related to the prosthesis may be specified by the user, such parameters may also be selected without any user input on the basis of information from published case studies, guidelines, trade magazines, articles, and the like. The prosthesis shape and size best-suited to the patient's anatomy may for example be chosen according to results of wear and fatigue tests performed for various types of prostheses and presented in a medical journal.

[0053] The priority level of the above-mentioned parameters may further be user-specified. For example, the user may specify, on a scale from 0 to 100, that, in decreasing order of priority, it is desired during the design process to minimize the amount of resected bone, respect the mechanical leg axis, varus/valgus alignment, minimum knee flexion, and minimum knee extension.

[0054] Once the information has been received, a virtual prosthesis, which meets the specified design parameters and is adapted to the patient under consideration may be designed by drawing a contour thereof. The designed virtual prosthesis may then be submitted electronically to the user for approval (step 108) over a suitable communications means, such as the Internet. For example, the design may be sent by email or presented to the user on a webpage. Other means of submitting the design may apply as will be apparent to a person skilled in the art.

[0055] Once the user receives the design, the latter may be approved or rejected (step 110). For this purpose, the user may be presented with a virtual 2D and/or 3D representation of the knee joint with the designed prosthesis coupled to a bone. Ligaments and cartilage as well as proposed bone cuts may also be illustrated on the 2D and/or 3D representation. Using such a representation, the user may verify whether the design parameters have been satisfied. For example, the user may verify the varus/valgus alignment, the degree of extension and flexion allowed by the proposed prosthesis design, and visualize the mechanical axis passing through the bones. If the design is rejected, the user may provide additional comments, corrections, as well as any other information useful for modifying the design to meet the desired criteria. For example, the user may adjust the contour of the designed prosthesis or correct the mechanical axis parameters. The user may further be prevented to effect corrections, which are contrary to design parameters. The method 100 may then return to the design step 106 and this iterative process may be repeated as long as the virtual prosthesis design has not been approved by the user.

[0056] Once the design is approved, it may be sent for manufacturing (step 112). Computer-aided machining (CAM) may be used for performing free-form machining of the prosthesis. For this purpose, machining parameters related for example to the prosthesis material, cutting tools, and cutting operations, may be defined. A machining trajectory used for producing the prosthesis may then be generated. A simulation may also be performed to enable accurate planning of the machining process. A computer numerical control (CNC) code specifying the tool paths as well as any additional information useful for avoiding machine collisions may then be generated and sent to the machining tool over a suitable communication link.

[0057] Referring to Figure 1b, the manufacturing step 114 illustratively comprises machining the prosthesis according to the virtual design (step 18) using a suitable device, such as a milling machine, a rapid prototyping machine, or the like. It may also be desirable (step 120) to manufacture for testing purposes the 3D bone model created at step 104 from segmented images of the patient's anatomical structures. In this case, the 3D model may be manufactured at step 122 by casting, molding, rapid prototyping, or any other suitable method.

[0058] Referring to Figure 1c, once the prosthesis, and potentially the 3D bone model, have been machined, the next step 116 illustratively comprises testing the prosthesis. The testing phase may comprise virtually testing (step 124) and/or physically testing (step 126) the manufactured prosthesis. The method then assesses whether the prosthesis passed the testing phase (step 128). If so, the prosthesis may be shipped at step 130 to the user for implantation in the patient's knee (step 30). Otherwise, the prosthesis is rejected at step 132 and the method 100 may either end or return to the design step 06 for adjusting the design and machining a new prosthesis according to corrections submitted during the testing phase.

[0059] Referring now to Figure 1d, virtually testing the prosthesis 124 may comprise scanning or otherwise digitizing the manufactured prosthesis at step 134 using a suitable capturing device, such as a radiograph or a 3D scanner. Once the prosthesis has been scanned, a 2D and/or 3D virtual representation thereof may be generated according to the pre-defined user parameters. The virtual representation of the prosthesis may then be compared to the original virtual prosthesis design obtained at step 106. If a 3D representation of the prosthesis is generated, the latter may be tested against the virtual 3D bone model obtained at step 104. Dimensional testing (step 136) may therefore be effected to ensure that the manufactured prosthesis may be precisely fitted on the bone once implanted. For example, this may be done by measuring the dimensions, e.g. the length, width, curvature, or the like, of the scanned prosthesis and comparing the measured dimensions against the dimensions defined in the original prosthesis design. If the dimensions do not match, this may indicate a flaw in the manufacturing process 4. It should be understood that the measured dimensions need not be equal to the dimensions of the original prosthesis design. Indeed, the manufactured prosthesis may pass the virtual test and be accepted so long as the measured dimensions are within a predetermined tolerance of the dimensions defined in the prosthesis design. The measured dimensions may also be compared to the dimensions of the virtual bone model in order to evaluate whether the machined prosthesis may be properly fitted on the patient's bones. For instance, it can be determined that the machined prosthesis may be fitted on the patient's bones if the measured dimension(s) (e.g. width) match, e.g. are within a predetermined tolerance of, the dimension(s) of the virtual bone model.

[0060] The virtual testing may also comprise assessing whether the scanned prosthesis may be properly coupled to the virtual 3D bone model (step 138). For this purpose, a scanned femoral component of the scanned prosthesis may be virtually positioned on the virtual 3D femur model for ensuring that the femoral component may be properly secured to the bone model using attachment mechanisms, such as pegs, provided on the prosthesis. It should be understood that the 3D bone model may comprise virtual representations of other anatomical structures, such as the fibula and patella. The scanned prosthesis, once positioned on the supporting virtual bone, may be mated with the articular joint surface of the virtual 3D bone model to further verify whether the machined prosthesis may be properly mated at the patient's articular joint. For instance, the scanned femoral component may be virtually positioned on the virtual 3D femur model and, when in place, mated with the articular surface of the virtual 3D tibial model. This allows to virtually verify that the machined femoral component may be matingly engaged with the articular surface of the patient's tibia to enable proper operation of the knee joint during physical activity.

[0061] Parameters, such as the spacing and alignment between the scanned prosthesis and the virtual 3D bone model, may be measured to quantify the virtual testing results. For example, a spacing between an inner surface of the scanned femoral component and an outer surface of the virtual femur may be measured. It will be apparent to a person skilled in the art that other dimensional testing methods may apply. In addition, although the femoral component of the prosthesis has been described to illustrate the testing phase, it should be understood that similar testing may be performed having regards to a tibial component of the prosthesis.

[0062] Referring now to Figure 1e, physically testing the prosthesis 126 may comprise assessing at step 138 whether the virtual 3D bone model created at step 104 has been manufactured at step 122 (illustrated in Figure 1b). If the virtual 3D bone model has not been manufactured, the method 100 may return to the step 124 of virtually testing the prosthesis described above. Otherwise, the machined prosthesis may be tested on the machined 3D bone model at step 140. Illustratively, non-destructive testing is performed in order to prevent damaging the patient-specific prosthesis. Such testing may imply fitting the machined prosthesis components on the machined 3D bone model to assess the dimensional (step 139) and coupling (step 140) parameters described above with regards to virtually testing the prosthesis. For example, if both the patient's femur and tibia have been machined and the machined prosthesis comprises a femoral component, the latter may be positioned on the machined femur for ensuring that the prosthesis may be properly mounted to the patient's femur during surgery. The machined femoral component, when in place on the machined femur, may also be mated with the articular surface of the machined tibia in order to evaluate proper fit prior to surgically implanting the prosthesis in the patient's body. If the prosthesis has been designed and machined with a textured inner and/or outer surface as a design parameter, the physical testing step 126 may further comprise assessing the rugosity of the prosthesis surface (step 141) using any suitable means, such as a digital roughness tester or the like. It should be understood that other suitable non-destructive testing methods may be used to evaluate whether the machined prosthesis meets design parameters. It should also be understood that virtual testing and physical testing may be performed separately of in combination to more thoroughly inspect the prosthesis.

[0063] Referring to Figure 2, there is illustrated a system 200 for manufacturing a prosthesis and inspecting the prosthesis post-manufacture. One or more server(s) are provided remotely and accessible via a network 210, such as the Internet, a cellular network, or others known to those skilled in the art. For example, a series of servers corresponding to a web server, an application server, and a database server may be used. These servers are all represented by server 202 in Figure 2. The server 202 may be accessed by a user, such as a medical professional, using a client device 214, such as a computer, a personal digital assistant (PDA), a smartphone, or the like, adapted to communicate with the server 202 via the network 210.

[0064] The server 202 may comprise, amongst other things, a plurality of applications 208a ... 208n running on a processor 206 coupled to a memory 202. It should be understood that while the applications 208a ... 208n presented herein are illustrated and described as separate entities, they may be combined or separated in a variety of ways.

[0065] One or more databases 212 may be integrated directly into the memory 204 or may be provided separately therefrom and remotely from the server 202 (as illustrated). In the case of a remote access to the databases 212, access may occur via any type of network 210, as indicated above. The various databases 212 described herein may be provided as collections of data or information organized for rapid search and retrieval by a computer. The databases 212 may be structured to facilitate storage, retrieval, modification, and deletion of data in conjunction with various data-processing operations. The databases 212 may consist of a file or sets of files that can be broken down into records, each of which consists of one or more fields. Database information may be retrieved through queries using keywords and sorting commands, in order to rapidly search, rearrange, group, and select the field. The databases 212 may be any organization of data on a data storage medium, such as one or more servers.

[0066] In one embodiment, the databases 212 are secure web servers and Hypertext Transport Protocol Secure (HTTPS) capable of supporting Transport Layer Security (TLS), which is a protocol used for access to the data. Communications to and from the secure web servers may be secured using Secure Sockets Layer (SSL). Identity verification of a user may be performed using usernames and passwords for all users. Various levels of access rights may be provided to multiple levels of users.

[0067] Alternatively, any known communication protocols that enable devices within a computer network to exchange information may be used. Examples of protocols are as follows: IP (Internet Protocol), UDP (User Datagram Protocol), TCP (Transmission Control Protocol), DHCP (Dynamic Host Configuration Protocol), HTTP (Hypertext Transfer Protocol), FTP (File Transfer Protocol), Telnet (Telnet Remote Protocol), SSH (Secure Shell Remote Protocol).

[0068] The memory 204 accessible by the processor 206 may receive and store data. The memory 204 may be a main memory, such as a high speed Random Access Memory (RAM), or an auxiliary storage unit, such as a hard disk, flash memory, or a magnetic tape drive. The memory 204 may be any other type of memory, such as a Read-Only Memory (ROM), Erasable Programmable Readonly Memory (EPROM), or optical storage media such as a videodisc and a compact disc.

[0069] The processor 206 may access the memory 204 to retrieve data. The processor 206 may be any device that can perform operations on data. Examples are a central processing unit (CPU), a front-end processor, a microprocessor, a graphics processing unit (GPU/VPU), a physics processing unit (PPU), a digital signal processor, and a network processor. The applications 208a ... 208n are coupled to the processor 206 and configured to perform various tasks as explained below in more detail. An output may be transmitted to the client device 214.

[0070] Figure 3a is an exemplary embodiment of an application 208a running on the processor 206. Images of anatomical structures of the patient's damaged knee joint are illustratively received by a prosthesis design module 216 as per the method 100 illustrated in Figure 1a. It should be understood that although the images may be sent from the client device 214 to the processor 206 through the network 210, the images may also be transferred to the processor 206 using a suitable device known to those skilled in the art, such as a CD, DVD, USB key, or the like, having the images stored thereon. The prosthesis design module 216 may then produce an output, which is transmitted to a machining module 218 whose output may in turn be sent to a machining tool as part of a CAM process. A prosthesis validation module 220 may further be provided, which takes as input scanned data of the machined prosthesis and identifies in an output whether the machined prosthesis is accepted or rejected. The prosthesis validation module 220 may further output results of the testing processed as per the method 100 of Figure 1a.

[0071] Figure 3b illustrates the prosthesis design module 216 in more detail. The prosthesis design module 216 illustratively comprises an image receiving module 222, an image segmentation module 224, a virtual design module 226, and a design approval module 228. The image receiving module 222 illustratively receives the anatomical images as an input and sends the received images to the image segmentation module 224, which segments the received images to create a virtual 3D bone model as per the method 100 of Figure 1a. The virtual 3D bone model may then be sent to the virtual design module 226 along with design parameters, such as prosthesis type, mechanical axis, minimum knee flexion and extension, varus/valgus alignment, and patient- related information, such as age, gender, and weight, which may be provided by the user.

[0072] The output of the virtual design module 226 is illustratively the virtual design of a prosthesis adapted to the virtual 3D bone model and meeting the additional design parameters. This output may then be sent to the design approval module 228, which either approves or rejects the design by evaluating whether design parameters are satisfied. If the design is rejected, the latter may be sent back to the virtual design module 226 for adjusting design parameters and generating a new design for approval. Otherwise, the approved design may be sent to the machining module 218 for manufacturing the prosthesis using CAM or any other suitable machining process. The virtual 3D bone model may also be sent from the virtual design module 226 to the design approval module 228 and subsequently to the machining module 218 for manufacturing the 3D bone model if desired. [0073] Figure 3c illustrates the prosthesis validation module 220 in more detail. The prosthesis validation module 220 illustratively comprises at least a dimensional test module 230 and a coupling test module 232. Other nondestructive test modules may also be provided. At least one of the dimensional test module 230 and the coupling test module 232 may be used to virtually test the machined prosthesis. For this purpose, the dimensional test module 230 and/or the coupling test module 232 may receive as input scanned data of the machined prosthesis. Upon receiving this data, the dimensional test module 230 and/or coupling test module 232 may test the prosthesis and either accept or reject the latter. For example, prosthesis dimensions may be measured by the dimensional test module 320 and/or proper attachment of the prosthesis to the bones or mating of the prosthesis surface to bone articular surface may be assessed by the coupling test module 232 as per the virtual testing step 124 of the method 100 of Figure 1a. An output representative of the results of the testing effected by the test modules 230 and/or 232 may be provided. If various test modules, as in 230 and 232, are in use, such an output may for example specify which test module accepted or rejected the prosthesis. In this manner, it may be possible to specifically identify such a test module and accordingly which test the prosthesis failed. This may prove useful when it is desired to adjust the design parameters for machining a new prosthesis for the same patient.

[0074] Referring to Figure 4a, during virtual testing of the prosthesis, the user may be presented on a user interface, e.g. a web interface 300, with the scanned data of the machined prosthesis, such as a femoral component 302, along with the virtual 3D bone model of the femur 304 and tibia 306. It should be understood that 3D models of other anatomical structures, such as the fibula and patella (not shown), may also be provided for testing purposes. In this manner, the user may measure the length, width, curvature, and other suitable dimensions, of the virtual femoral component 302 and compare the measured dimensions to the dimensions of the virtual femur 304 and tibia 306. The user may therefore assess whether the femoral component 302 may be precisely fitted on the bones. Such measurements may be performed using graphical tools, such as a virtual ruler 308 and a virtual protractor 310 presented to the user on the web interface 300. It should be understood that other virtual tools known to those skilled in the art to be suitable for estimating bone and prosthesis dimensions, may be presented. In order to facilitate user interaction and manipulation of the virtual objects, such as the femoral component 302, femur 304, and tibia 306, graphical tools, including but not limited to a zoom tool 311 , a rotation tool 313, and a "drag-and-drop" tool 315, may also be presented to the user on the web interface 300. Moreover, the user may adjust the level of transparency of the virtual objects in order to more readily visualize different parts thereof.

[0075] A comments section 312 may further be provided to enable the user to enter test results, such as measurement discrepancies or other inaccuracies. For example, the user may specify in the comments section 312 that the curvature of the virtual femoral component 302, as measured using the virtual protractor 310, does not conform to the curvature of the virtual femur 304. The user may also measure, using the virtual ruler 308, a spacing between the inner surface 316 (see Figure 4b) of the virtual femoral component 302 and the articular surface 318 (see Figure 4c) of the virtual femur 304. If such a spacing is above a predetermined threshold, it may be determined that the femoral component 302 failed the virtual test and, as such, that the machined femoral component (not shown) should be rejected. Corrections to the prosthesis design may also be suggested. The entered information, which may further be flagged using an option 314, such as a flag, push-button, or the like, may then be used to adjust the design for subsequent machining of a new prosthesis.

[0076] Referring to Figure 4b, the user may further virtually position the virtual femoral component 302 on the virtual femur 304 to ensure that the femoral component 302 is adapted to be properly fitted thereon. For this purpose, fixations or other attachment mechanisms, such as virtual pegs 317, which may be a representation of the real pegs provided on the machined femoral component, may be shown on the virtual femoral component 302. Virtual representations of corresponding apertures (not shown), which may be drilled in the femur during surgery to receive the femoral component, may also be represented on the virtual femur 304. Using the graphical tools provided on the web interface 300, the user may then attempt to position the virtual pegs 317 into the virtual apertures. Indeed, as discussed above, the user may use the zoom tool 311 , rotation tool 313, and/or "drag-and-drop" tool 315 to manipulate the virtual objects. The user may also adjust the level of transparency thereof, for example by making the virtual femur 304 transparent, as illustrated in Figure 4b, to enable visualization of the features of the virtual femoral component 302, such as the virtual pegs 317, when positioning the latter on the virtual femur 304. If the attempt to mount the virtual femoral component 302 on the virtual femur 304 fails, it may be determined that the machined femoral component may not be properly fitted on the patient's femur during surgery, and, as such, that the prosthesis should be rejected.

[0077] Referring to Figure 4c, with the virtual femoral component 302 in place on the virtual femur 304, the user may further virtually mate the outer surface 320 of the virtual femoral component 302 with the articular surface 322 of the virtual tibia 306 using the graphical tools provided on the web interface 300. For example, the user may mate both surfaces 320 and 322 along the cranial- caudal direction A. The user may also position the virtual femur 304 having thereon the virtual femoral component 302 in a direction angled relative to the cranial-caudal direction A. In this manner, it may be verified whether the surface of the femoral component 302 may be properly fitted to the articular surface of the patient's tibia as represented by the virtual 3D bone model. Proper operation of the knee joint with the prosthesis in place may thus be verified. For example, if the outer surface 320 of the virtual femoral component 302 fails to matingly engage the articular surface 322 of the virtual tibia 306 when the virtual femur 304 having thereon the virtual femoral component 302 is in a direction parallel or angled relative to the cranial-caudal direction 302, it may be determined that the machined femoral component may not be properly mated with the patient's tibia, and, as such, that the prosthesis should be rejected.

[0078] It should be understood that at least one of the above virtual tests may be performed to validate the prosthesis. Moreover, although the virtual testing has been illustrated as being effected on a 3D representation of the virtual objects, 2D representations may be used as well. Also, as discussed above, any test results, comments, and/or corrections may be entered in the comments section 312 and/or flagged using the option 314.

[0079] Referring to Figure 5, during physical testing of the prosthesis, the user may position the machined femoral component 400 on the machined femur 402 to ensure that the prosthesis may be properly mounted to the patient's bone during surgery. For this purpose, the user may assess whether the femoral component 400 may be securely mounted on the machined femur 402 using attachment mechanisms (not shown) machined in the femoral component 400. Once the femoral component 400 is in place on the femur 402, the articular surface 404 of the femoral component 400 may further be mated with the articular surface 406 of the machined tibia 408 in order to evaluate whether both surfaces 404, 406 may be properly engaged prior to surgically placing the prosthesis in the patient's body.

[0080] As with virtual testing, physical testing may further comprise flexing the femur 402, with the femoral component 400 placed thereon, relative to the femur 402 at the articular joint, such that a longitudinal axis X of the femur 402 is at an angle relative to a longitudinal axis Y of the tibia 408. Such a test may evaluate proper mating of the articular surfaces 404 and 406 during flexing of the knee joint as should be the case during the patient's normal walking, running, or other activities. If the articular surface 406 of the femoral component 400 has been designed and machined to be textured, the physical testing phase may further comprise assessing the rugosity of the surface 406 using any suitable means. It should also be understood that at least one of the above physical tests may be performed to validate the machined prosthesis.

[0081] It should also be understood that the virtual and physical tests may be performed separately or in combination. Although the virtual and physical testing phases have been illustrated with reference to the femoral component 400 and the virtual representation thereof 302, it will be apparent that such testing may also be performed with respect to the tibial component 4 0. [0082] If the machined prosthesis passes the virtual and/or physical tests, the prosthesis may then be shipped to the user who requested manufacturing thereof. Otherwise, the design phase may be started over taking into account the user's comments, if any, in order to manufacture a new prosthesis for the same patient.

[0083] Using the testing approach described herein, proper fit of the prosthesis components may therefore be evaluated prior to surgically implanting the latter in the patient's body. As a result, misalignment and less than optimal implantation of the prosthesis relative to the patient's anatomy may be reduced. This, in turn, may improve the outcome of the surgery.

[0084] While illustrated in the block diagrams as groups of discrete components communicating with each other via distinct data signal connections, it will be understood by those skilled in the art that the present embodiments are provided by a combination of hardware and software components, with some components being implemented by a given function or operation of a hardware or software system, and many of the data paths illustrated being implemented by data communication within a computer application or operating system. The structure illustrated is thus provided for efficiency of teaching the present embodiment. It should be noted that the present invention can be carried out as a method, can be embodied in a system, and/or a computer readable medium. The embodiments of the invention described above are intended to be exemplary only. The scope of the invention is therefore intended to be limited solely by the scope of the appended claims.

Claims

CLAIMS:

1. A computer-implemented method for inspecting a machined object having a first object surface adapted to matingly engage a first articular surface of a first bone, the method comprising executing on a processor program code for:

receiving a first digital bone representation, the first digital bone representation a digital representation of the first bone and comprising a first virtual articular surface representative of the first articular surface;

receiving a digital object representation, the digital object representation a digital representation of the machined object and comprising a first virtual object surface representative of the first object surface;

coupling the first virtual object surface to the first virtual articular surface; approving the machined object if the coupled first virtual object surface and first virtual articular surface are matingly engaged; and

rejecting the machined object otherwise.

2. The method of claim 1 , further comprising, subsequent to rejecting the machined object, receiving correction data indicative of at least one correction to be applied to at least one parameter of an original design of the machined object to generate a modified design to be used for creating a new machined object.

3. The method of claim 1 or 2, further comprising receiving a design value of at least one first dimension, the design value defined in an original design of the machined object, measuring the at least one first dimension in the digital object representation, comparing the measured at least one first dimension to the design value, and approving the machined object if the measured at least one first dimension is within a first predetermined tolerance of the design value.

4. The method of any one of claims 1 to 3, further comprising measuring at least one second dimension of the digital object representation, measuring the at least one second dimension of the first digital bone representation, comparing the measured at least one second dimension of the digital object representation to the measured at least one second dimension of the first digital bone representation, and approving the machined object if the measured at least one second dimension of the first digital bone representation is within a second predetermined tolerance of the measured at least one second dimension of the digital object representation.

5. The method of claim 3 or 4, wherein the at least one first dimension and the at least one second dimension are selected from the group consisting of a length, a width, and a curvature.

6. The method of claim 5, further comprising measuring at least one third dimension indicative of a position of the digital object representation relative to the first digital bone representation, comparing the measured at least one third dimension to a threshold, and approving the machined object if the at least one third dimension is below the threshold.

7. The method of claim 6, wherein measuring the at least one third dimension comprises measuring a spacing between the first virtual object surface and the first virtual articular surface.

8. The method of claim 6 or 7, wherein receiving the first digital bone representation comprises receiving at least one anatomical direction of the first bone and further wherein measuring the at least one third dimension comprises measuring an alignment of the digital object representation relative to the at least one anatomical direction.

9. The method of any one of claims 1 to 8, wherein receiving the digital object representation comprises receiving a digital representation of at least one attachment means provided with the machined object, the at least one attachment means adapted to be received in at least one aperture formed in the first bone for retaining the machined object in place relative to the first bone, and receiving the first digital bone representation comprises receiving a digital representation of the at least one aperture, and further comprising approving the machined object if the digital representation of the at least one fixation is received in the digital representation of the at least one aperture when the first virtual object surface is coupled to the first virtual articular surface.

10. The method of claim 8 or 9, wherein the received digital object representation comprises a second virtual object surface representative of a second object surface opposite the first object surface, and further comprising receiving a second digital bone representation, the second digital bone representation a digital representation of a second bone and comprising a second virtual articular surface representative of a second articular surface of the second bone, the second articular surface adapted to matingly engage the second object surface, coupling the second virtual object surface to the second virtual articular surface, approving the machined object if the coupled second virtual object surface and second virtual articular surface are matingly engaged, and rejecting the machined object otherwise.

11. The method of claim 10, further comprising positioning, with the second virtual object surface coupled to the second virtual articular surface, the digital representation of the machined object at an angle relative to the at least one anatomical direction and approving the machined object if the coupled second virtual object surface and second virtual articular surface are matingly engaged with the digital representation of the machined object so positioned.

12. The method of any one of claims 1 to 1 , wherein receiving the digital object representation comprises receiving a digital representation of a machined object created using patient-specific modeling.

13. A system for inspecting a machined object having a first object surface adapted to matingly engage a first articular surface of a first bone, the system comprising:

a memory;

a processor; and at least one application stored in the memory and executable by the processor for receiving a first digital bone representation, the first digital bone representation a digital representation of the first bone and comprising a first virtual articular surface representative of the first articular surface, receiving a digital object representation, the digital object representation a digital representation of the machined object and comprising a first virtual object surface representative of the first object surface, coupling the first virtual object surface to the first virtual articular surface, approving the machined object if the first coupled virtual object surface and first virtual articular surface are matingly engaged, and rejecting the machined object otherwise.

14. The system of claim 13, wherein the at least one application is executable by the processor for receiving, subsequent to rejecting the machined object, correction data indicative of at least one correction to be applied to at least one parameter of an original design of the machined object to generate a modified design to be used for creating a new machined object.

15. The system of claim 13 or 14, wherein the at least one application is executable by the processor for receiving a design value of at least one first dimension, the design value defined in an original design of the machined object, measuring the at least one first dimension in the digital object representation, comparing the measured at least one first dimension to the design value, and approving the machined object if the measured at least one first dimension is within a first predetermined tolerance of the design value.

16. The system of any one of claims 13 to 15, wherein the at least one application is executable by the processor for measuring at least one second dimension of the digital object representation, measuring the at least one second dimension of the first digital bone representation, comparing the measured at least one second dimension of the digital object representation to the measured at least one second dimension of the first digital bone representation, and approving the machined object if the measured at least one second dimension of the first digital bone representation is within a second predetermined tolerance of the measured at least one second dimension of the digital object representation.

17. The system of claim 15 or 16, wherein the at least one application is executable by the processor for measuring at least one third dimension indicative of a position of the digital object representation relative to the first digital bone representation, comparing the measured at least one third dimension to a threshold, and approving the machined object if the at least one third dimension is below the threshold.

18. The system of claim 17, wherein the at least one application is executable by the processor for measuring the at least one third dimension comprising measuring a spacing between the first virtual object surface and the first virtual articular surface.

19. The system of claim 17 or 18, wherein the at least one application is executable by the processor for receiving the first digital bone representation comprising receiving at least one anatomical direction of the first bone and further wherein the at least one application is executable by the processor for measuring the at least one third dimension comprising measuring an alignment of the digital object representation relative to the at least one anatomical direction.

20. The system of any one of claims 13 to 19, wherein the at least one application is executable by the processor for receiving the digital object representation comprising receiving a digital representation of at least one attachment means provided with the machined object, the at least one attachment means adapted to be received in at least one aperture formed in the first bone for retaining the machined object in place relative to the first bone, for receiving the first digital bone representation comprising receiving a digital representation of the at least one aperture, and for approving the machined object if the digital representation of the at least one fixation is received in the digital representation of the at least one aperture when the first virtual object surface is coupled to the first virtual articular surface.

21. The method of claim 19 or 20, wherein the at least one application is executable by the processor for receiving the digital object representation comprising a second virtual object surface representative of a second object surface opposite the first object surface, for receiving a second digital bone representation, the second digital bone representation a digital representation of a second bone and comprising a second virtual articular surface representative of a second articular surface of the second bone, the second articular surface adapted to matingly engage the second object surface, for coupling the second virtual object surface to the second virtual articular surface, for approving the machined object if the coupled second virtual object surface and second virtual articular surface are matingly engaged, and for rejecting the machined object otherwise.

22. The method of claim 21 , wherein the at least one application is executable by the processor for positioning, with the second virtual object surface coupled to the second virtual articular surface, the digital representation of the machined object at an angle relative to the at least one anatomical direction and for approving the machined object if the coupled second virtual object surface and second virtual articular surface are matingly engaged with the digital representation of the machined object so positioned.

23. A method for inspecting a machined object having a first object surface adapted to matingly engage a first articular surface of a first bone, the method comprising:

receiving a first digital bone representation, the first digital bone representation a digital representation of the first bone and comprising a first virtual articular surface representative of the first articular surface; and

at least one of

virtually inspecting the object, the virtual inspection comprising receiving a digital object representation, the digital object representation a digital representation of the machined object and comprising a first virtual object surface representative of the first object surface;

coupling the first virtual object surface to the first virtual articular surface;

approving the machined object if the coupled first virtual object surface and first virtual articular surface are matingly engaged; and

rejecting the machined object otherwise; and

physically inspecting the object, the physical inspection comprising

machining the first digital bone representation into a first machined bone comprising a first machined articular surface representative of the first articular surface;

coupling the first object surface to the first machined articular surface;

approving the machined object if the coupled first object surface and first machined articular surface are matingly engaged; and

rejecting the machined object otherwise.

24. The method of claim 23, wherein the received digital object representation comprises a second virtual object surface representative of a second object surface opposite the first object surface, and further comprising receiving a second digital bone representation, the second digital bone representation a digital representation of a second bone and comprising a second virtual articular surface representative of a second articular surface of the second bone, the second articular surface adapted to matingly engage the second object surface.

25. The method of claim 24, wherein virtually inspecting the object comprises coupling the second virtual object surface to the second virtual articular surface, approving the machined object if the coupled second virtual object surface and second virtual articular surface are matingly engaged, and rejecting the machined object otherwise and physically inspecting the object comprises machining the second digital bone representation into a second machined bone comprising a second machined articular surface representative of the second articular surface, coupling the second object surface to the second machined articular surface, approving the machined object if the coupled second object surface and second machined articular surface are matingly engaged, and rejecting the machined object otherwise.

26. A computer readable medium having stored thereon program code executable by a processor for inspecting a machined object having a first object surface adapted to matingly engage a first articular surface of a first bone, the program code executable for:

receiving a first digital bone representation, the first digital bone representation a digital representation of the first bone, and comprising a first virtual articular surface representative of the first articular surface;

rejecting the machined object otherwise.