Talus formation and implantation method

A process for printing a talus implant comprising the steps of scanning a joint for a damaged talus, and scanning a contralateral joint for a healthy talus. Next, the process includes obtaining dimensions for a talus based upon an initial scan and then obtaining dimensions for a talus based upon the scan of the contralateral joint. Next the process includes inverting the dimensions of the talus in the contralateral joint and then comparing the dimensions of the calculated talus with a pre-set of dimensions in a database. Next the process includes exporting a set of dimensions to a printer to print a talus implant.

BACKGROUND OF THE INVENTION

At least one embodiment of the invention relates to a talus implantation and formation method. A talus bone or ankle bone is one of a group of foot bones known as the tarsus. The tarsus forms the lower part of the ankle joint through its articulations. The talus bone can transmit the entire weight or a substantial portion of the weight of the body to the foot. The talus bone is extensively covered in cartilage. The talus forms part of the talocalcaneonavicular joint along with the calcaneus or heel bone and the navicular. The talus can comprise the following basic parts, the head, the neck and the body.

Talus injuries can be difficult to heal. For example, the talus bone lacks a good blood supply and as such those with a broken talus bone may not be able to walk for many months without crutches. Thus, many patients find a need for a talus implant.

The insertion of a talus implant can start with an incision to the ankle joint such that it involves exposure of the ankle joint and eventual movement or removal of obstruction of the extensor hallucis longus tendon, the anterior tibial artery, the extensor longus muscle. Once the talus bone that is injured is exposed it can be removed from the ankle joint. This talus can be held in place by the syndesmosis and anterior tibiofibular ligament as well as the anterior talofibular ligament and the superficial deltoid ligament. Once a talus bone is removed, a talus implant can be inserted into its place. However, since the talus bone can interact with other bones in different joints there is a need for a talus replacement and/or implant method and system so that a new talus can be accurately created and then implanted in a patient for future use.

SUMMARY OF THE INVENTION

In at least one embodiment of the invention, there is a process for creating a talus and then implanting the created talus into a patient. For example, the process starts with a first step of scanning a joint. Once the joint is scanned such as using a cat scan, a first generic image of a talus is created. This image is a 3-D image that is created from the scan of the talus, wherein the following dimensions are calculated-talar height, talar arc length and talar width. Next the system can determine the alignment dimensions. The alignment dimensions can include the tibiotalar, the talar tilt angle, the talar declination angle, Boehler's angle, and Meary's angle. In addition, the patient's demographic information is input into the system as well. Once the talus has been removed it is examined for damage along with the surrounding area to determine possible interactions for the talus future talus implant. The possible interactions include interactions with neighboring bones as well as the surrounding joint. Depending on the level of damage to the talus the contralateral hindfoot can also be scanned. From this scan the system can invert the dimensions or take the mirror image of the dimensions to then fine tune or create the image of the talus. In at least one embodiment, based upon the above dimensions, the mirror image dimensions and optionally the patient's demographic information, can be used to determine which type of talus to use. For example, this information can be matched with an existing database of previous patients with respect to the dimensions of the prospective talus. Next, the implant is printed. Once the implant is printed it is coated. The coating can be of any suitable coating but in at least one embodiment is a nickel-plated cobalt coating. One process for creating the plating or coating could be through EBM or electron beam melting. Next, the implant is polished. Once the implant has been polished, it is reinserted into the user's body and then the implant can be evaluated for existing interactions. If there are any unexpected interactions, then the talus or the surrounding joint around the talus can be modified to better fit the talus inside of the user's body. Based upon the different interactions with other bones with the talus multiple different paths could be formed.

For example, a first path can be formed where there is no arthritis between the adjacent bones. Thus, a talus can be formed and polished and coated with no further modifications being necessary. Along a second path, there can be discovered arthritis in the subtalar joint wherein a lattice is formed on a bottom surface of the talus. Alternatively, a third path can be formed wherein there is extensive arthritis around a substantial portion of the joints affecting the talus such that there are multiple faces having a lattice structure. In addition, there can be a fourth path for the creation of the talus wherein there is discovery of arthritis of the navicular joint which includes exposure of a face having a lattice to the navicular. A fifth path can include any combination of the above paths to form a hybrid structure of a talus having multiple faces which contain a lattice structure.

Ultimately there can be many different paths for constructing or 3D printing a talus implant or a talus implant with a partial or substantial reconstruction of an ankle joint.

DETAILED DESCRIPTION

FIG.1is a flow chart for the process for creating at least one talus implant and then implanting the talus into a patient's joint. For example, the process starts with step S1wherein a high resolution CT or MRI is taken of an affected patient's talus as well as the contralateral unaffected ankle joint in step S1. Next, in step S2, the raw data is imported into the system such as into a computer100, which could be used to represent any one of first initial computer140, second computer150, or application server130. Upon viewing the scans the scans can be inspected so that the affected ankle joint is inspected for arthritis of the talus or tibial joint, the talus and the navicular joint and the talus and the calcaneus joint. Upon inspection of the joint, a particular path can be selected in step S4. For example, if the patient has no visible or apparent arthritis outside of the failure of the initial talus bone, then a single total talus replacement can be fabricated in for example step S5. This path would be considered the first path to select. Other paths are also possible such as path2wherein there is recognized arthritis of the subtalar joint wherein there can be a design of the total talus with a lattice on the bottom to fuse to the calcaneus bone in step S6. Alternatively, in step S7, path3can comprise recognizing that there is arthritis of the ankle joint, wherein there is a total talus to combine with a commercially available total ankle system. Alternatively, there can be in path4a recognition of arthritis of the navicular joint wherein there is a design of a total talus with a lattice to fuse to the navicular bone in step S8. Alternatively, in step S9there can be some combination of the paths1,2,3, and4in a new path5wherein there is some combination of arthritis to the ankle joint.

Once the path has been selected the contralateral talus (disposed on the opposite unaffected leg) that has been scanned can be mirrored in image and dimensions to the affected side. Once the talus has been mirrored, the scanned talus from the affected side can be removed or separately stored so as to not affect the properly mirrored version in step S10. However, if the contralateral side is not available then the system can use an algorithm to compare the affected talus to the talus available in a pre-set database. The pre-set database can be in the form of a database stored in database server120and reviewed by a processor such as microprocessor102in application server130. The algorithm can include examining the talus based upon dimensions such as an the overall length of the talus (see dimension10ainFIG.2B), the overall width of the talus such as dimension17ainFIG.2B, the height of the talus19aor the length of the neck of the talus14aas well.

Next, the process proceeds to step S12wherein the talus is shaped and sized using the dimensions calculated by either the mirror image of the contralateral talus or via the dimensions of the talus in the database to create a new talus for printing and production. This step involves first creating the base talus and then modifying the talus to fit one of the above affected paths. For example, any one of the paths such as path1listed in step S5, path2listed in step S6, path3listed in step S7or path8listed in step S8.

Next, in step S13the system creates a solid talus by printing the talus via 3D printing. An example of a talus that is created is shown inFIGS.2A-2Bwith the talus being implanted as shown inFIG.2C.

Next, in step S14the talus can be polished to a mirror finish. Next, in step S15as an option, the talus can also be coated with a coating. The coating can be of any suitable coating but in at least one embodiment is a nickel-plated cobalt coating. Next, in step S16the talus can be delivered to the surgery. The talus can be shipped as part of a kit which involves repair of other parts of the ankle joint, or alternatively, it can be shipped alone. Next, in step S17the surgeon can remove the dead talus, and then implant the new talus as shown in step S18. An example of the new talus being implanted is shown inFIG.2C.

FIG.2Ais a side view of a talus implant10which includes a base or body section12a neck section14and a head section15. In addition, there are shown the medial process16the lateral process18and the posterior process20as well. On top of the body section12is an articular surface17for the distal tibia dome. The talus can also have pre-set dimensions wherein there is a pre-set dimension for the neck of the talus as dimension14a. In addition, there is a height of a talus19aas well as a width of the talus17aand the overall length of the talus10acan also be calculated. These dimensions can be taken from an existing talus that is affected and should be removed, or alternatively these dimensions can be taken from a contralateral talus and then derived by taking a mirror image of the talus to create the dimensions of a talus implant. Alternatively, the dimensions of the affected or compromised talus if not entirely destroyed could be compared to dimensions on an existing database to determine from storage in a database the appropriate dimensions to construct or print a talus implant.

FIG.2Cshows the talus10that is implanted into an ankle joint. This talus10is shown positioned between a tibia32, a fibula30, a calcaneus36and a navicular34. The talus implant is therefore created to fit inside of this ankle joint so that the different joints between the talus10and the surrounding bones are created once the talus is implanted into the joint. The aboveFIGS.2A-2Cshow the design and implantation of the talus implant into a joint that is not affected by arthritis. However, after scanning a joint, different types of a talus implant can be created.

For example,FIG.3shows an alternative process for creating a talus implant. With this process steps S1-S4are substantially the same. However if during examination it is decided that path2is the correct path, then there is a design so that it handles the arthritis of the subtalar joint so that a talus is designed with a lattice on the bottom to fuse to the calcaneus in step S6. Thus, in step S6athe ankle joint can be examined so that the talus such as talus10band the calcaneus such as the calcaneus36are examined for interaction. In addition, as described inFIG.1the contralateral talus is mirrored to the affected side and once the dimensions of the contralateral talus are taken in step S10a. Alternatively, since the contralateral talus does not have the specific interactions between the affected talus and the arthritic joint between the talus and the calcaneus, this step of removing the affected talus can be skipped in step S10b. If the contralateral side is not available, then an algorithm is used to compare the affected talus to the talus available in the database such as in database server120in step S11.

Once the talus is shaped, the application server130can used computer software or an algorithm to modify the implant to the affected paths. This includes forming a lattice or mesh for creating interactions on a bottom surface of the talus as shown inFIGS.4A and4Cwhich show both a mesh29and a post21disposed on the underside of the talus10bas described in step s12a. Next, the application server130and/or processing computers140and/or150through an associated microprocessor such as microprocessor102can create the solid talus through 3-D printing in step S13. Next, the talus can optionally be polished to a mirror finish in step S14. However, since the bottom of the talus10bis created with a roughened or lattice or mesh surface structure the bottom surface of the talus such as the mesh29is not polished. Next, in step S15the talus is coated. Next in step S16the talus is delivered to surgery wherein in step S17the dead talus is removed and in step S18the new talus is implanted.

FIG.4Ais a side view of the talus10bwhich includes a base or body section12, a neck14and a head15. There is a lateral process18as well as an under mesh side29with an optional post21. Post21extends down from the under mesh side of the talus. Drill holes23and25are shown extending through the talus, particularly through the neck of the talus and on to the underside of the talus. The mesh29can be formed in any suitable shape but in at least one embodiment it is formed as a lattice structure having repeating honeycomb patterns. These repeating honeycomb patterns are suitable for interactions with other adjacent bone structures. In at least one embodiment shown inFIG.4Athere is a post hole14bin neck14, and a head positioned adjacent to post hole14b. There is also body12which extends down to lateral process18. Disposed adjacent to lateral process18is a post21. Post21is formed with a lattice structure as well. The post21is formed to interact with adjacent bone structure, such that there is inter-lattice bone growth to create a fusion between this structure and the adjacent bone structure. The post21is configured to create subtalar fusion to the calcaneus bone.

FIG.4Dshows the view of the talus installed in an ankle joint. This ankle joint is formed by the fibula30, the tibia32, the calcaneus36and the navicular34all joining around the talus10ato form the ankle joint.

FIG.5is a flow chart of the process for forming an implant based upon the third path outlined inFIG.1. For example, with this process, there is the scanning of the affected area and the contralateral area in step S1. Next, the raw data is imported in step S2. Next, in step S3the affected ankle joint is inspected for arthritis, wherein the area inspected includes the talus, the tibia, the fibula, the navicular joint, and the talus/calcaneus joint for arthritis. Next, in step S4the practitioner can determine which path to follow. In at least one embodiment, such as in any one of the embodiments disclosed inFIGS.1,3,5and7the determination of which path to follow can be formed via a decision by a practitioner selecting the path or via an assistance from a program or algorithm determining that there is arthritis in the joint and then that algorithm determining via an application server such as application server130determining that there is arthritis in at least one joint. Next, in step S7the system determines that there is arthritis in the ankle joint so that there is a total talus design to combine with a commercially available total ankle system. Since there is extensive arthritis to the joint, the system and/or practitioner can examine the entire contralateral ankle joint including the calcaneus, the navicular the tibia and the fibula in step S7a. Next, in step S10the contralateral talus is mirrored to the talus on the affected side. If the sizing and shape of the contralateral talus appears to fit inside of the affected area, then the dimensions of the affected side talus are removed from use in the algorithm to determine the proper size and shape of the talus in step S10. Next, in step S11if the contralateral side is not available then an algorithm is used to compare the dimensions of the affected talus to a talus available in the database. As described above, the algorithm includes taking the dimensions of the talus including the length of the talus, the width of the talus, the length of the neck of the talus, the height of the talus. In addition, some of the additional factors that can be used include the size, weight, bone structure, and gender of the patient to determine the proper sizing of a talus implant for the patient's affected joint.

Next, in step S12bonce the talus is shaped, the system including the application server130can be used to determine the affected paths including the interactions with the calcaneus, the navicular, the tibia, and the fibula. Next, in step S13, the system can create the solid talus through 3-D printing of the talus. Next, in step S14, the talus can be selectively polished. Next, in step S15the talus can be selectively coated. The coating as described above can be a nickel-plated cobalt coating. Next, in step S16, the talus can be delivered to surgery so that it is available for implant. In this case the talus can be delivered together with a total ankle replacement system. In step S17the dead talus can be removed while in step S18the new talus can be implanted.

FIGS.6A-6Cshow the designs that can be implanted into an ankle joint. For example, with this design there is a talus10cwhich has a body section12. There is also shown a lateral process18, a posterior process20, along with a neck14and a post hole14b. As shown inFIG.6Bthere is a first articular surface17cfor the tibia, as well as a second articular surface17dfor the fibula.FIG.6Cshows another view which includes a partial ankle replacement, which includes a tibia post70which replaces an affected tibia. This tibia post70includes a tibia plate72for interaction with the talus implant10c.

The talus implant is shown inFIG.6Cas being positioned adjacent to the fibula30, the navicular34and the calcaneus36. The tibia post70is configured to be screwed into an end of a tibia bone so as to replace a damaged end of a tibia bone.

FIG.7shows another version of the process which was outlined inFIGS.1,3, and5. Steps1-4are the same as in the other flowcharts ofFIGS.1,3, and5. With step S8, the fourth path is chosen, wherein a practitioner or algorithm determines the fourth path for the creation of the talus with respect to an arthritic condition of the navicular joint. Thus, in step S3, the practitioner or system (algorithm on application server130) can examine the interaction of the talus and the navicular bone in the affected area for arthritis. If there is discovered any form of arthritis in this affected area then the fourth path in step S8is chosen. Along with the examination of the joint in the affected area, the contralateral joint is also examined such that the navicular bone, the talus bone and the interaction between the talus bone and the navicular bone is examined in step S8ato determine whether there is any arthritis in the affected joint. Next, in step S10the contralateral talus is mirrored so that the proper dimensions of the talus can be created. If the size and shape of the talus is correctly mirrored and created, then the dimensions of the affected talus are removed from the calculation of the talus to be printed. If however, the contralateral side in step S11is not available then the system such as application server130can use an algorithm to compare the affected talus to a talus available in a database. This calculation is based upon the perceived appropriate dimensions of a talus including its overall length, the length of the neck, its width and its height. Other variables such as the demographic information about the patient can also be used in this determination.

Once the talus is shaped, the system such as application server130can determine in step S12C whether to modify the implant to make the implant more receptable to interacting with a navicular bone positioned adjacent to the implant. The different calculations that can be performed to reshape the talus can be based upon the amount of affected area for interaction with the navicular bone, the shape of the adjacent navicular bone, the strength or mass or density of the adjacent navicular bone as well as the demographics of the patient (age, gender, weight, body mass etc). Next in step S13a solid talus can be created through 3D printing. The talus bone can be created so that it has a mesh surface that interacts with an adjacent navicular bone as well as an adjacent calcaneus bone or an adjacent tibia or fibula bone as well.

Next, in step S14the talus is polished to a mirror finish. Next, the talus is optionally coated in step S15. In step S16the talus is delivered to surgery. During surgery in step S17, the talus is removed, while in step S18the talus is implanted into the patient.

FIGS.8A-8Dshow the different parts of the talus as it is created. For example, there is shown a talus10dwhich has a mesh underside29, a post21a neck14, a post hole14bshown inFIG.8Awhich is a side view of the talus. The mesh, or lattice structure29has an uneven surface and which can extend beyond the outer frame such as body12. This mesh or lattice structure is configured to create interstitial bone growth that leads to fusion to an adjacent bone such as an adjacent calcaneus bone.FIG.8Bis a top view of the talus which includes a first articular surface17cfor interaction with a tibia, and a second articular surface17dfor interaction with a fibula. Screw holes23and25are shown in the neck region14of the talus. There is also a lateral process18shown inFIG.8B.

FIG.8Cshows a side view of the talus which shows the talus implant having a mesh face that therefrom. With this design, there is a screw hole28, a post hole14band a mesh side face29. The mesh side face29is made from a mesh or lattice structure.

With this design there is also an additional face14cwhich is in place of the head15. This additional face14chas a mesh or lattice structure which can be in a honeycomb pattern and which in at least one embodiment extends beyond the outer fame and allows for interstitial bone growth that encourages meshing with an adjacent navicular bone. The openings of the honeycomb pattern can be the same in dimension or vary in their size such as be wider at the outer extremity while narrowing as it moves inward towards the center of the body. In addition, this face includes a screw hole14d. Ultimately, this additional face14cis configured to interact with the navicular such as navicular34and therefore form an interaction with navicular34so that the mesh or lattice structure can selectively bond to the navicular. With any one of the mesh or lattice structures present, a growth chemical, solution, or material can be injected into the lattice structure before implantation so that once the implant is inserted into the body, the lattice interacts with an adjacent bone to promote bone growth into the lattice.

FIG.8Dshows a side perspective view of the talus10cbeing inserted into the ankle joint. In this view, there is a fibula30, a tibia implant70and a tibia plate72shown positioned adjacent to the fibula30. There is also shown the calcaneus36, and the navicular34as well. In addition, in this view there are screw holes23and25which allow for the insertion of screws into the implant and for securing the implant into adjacent areas, particularly into the fibula.

FIG.9is a schematic block diagram of a computer which is used to process the information described above such as the images and dimensions of the existing talus, the mirror image talus and the three (3) dimensionally printed talus. For example, there is a computer100which includes a motherboard101and a microprocessor102which is coupled to the motherboard. In addition, there is a memory104coupled to the motherboard. The memory can be in the form of a RAM memory such as SRAM (Static Ram), DRAM (Dynamic Ram), SDRAM (Synchronous Dynamic Ram), DDR SDRAM (double data rate SDRAM). Any other type of suitable ram can also be used as well. The computer can also have input and output ports (I/O) ports106which can be in the form of serial, USB firewire or any other sort of input or output ports. A TCP/IP port108can also be used which is coupled to a network interface107. A network interface can be in the form of a wireless or wired network interface wherein the network interface is associated with a MAC address as well as a TCP/IP identity on a network. In addition, coupled to the motherboard101is a video processor/video card110which is configured to read any input of video signals and/or process any input of video signals. A mass storage112is also coupled to the hard drive. The mass storage112can be in the form of a hard drive. Furthermore, there is a power supply114which is coupled to the motherboard101as well. This computer can be representative of any one of the computers shown inFIG.10such as any one of database server120, application server130, first initial processing computer140, second initial processing computer150.

FIG.10shows a network layout of a computer network that can be used to carry out the processes shown inFIGS.1,3,5,7, and11. For example, there is a computer network which includes a connection through router or through the internet115. At least one node on this network includes a database server130. There is also an application server which can be in communication with database server130either through the internet115or through a router such as a private network. The first initial processing computer and the second initial processing computers are configured to be coupled to associated scanners such as scanner145and scanner155. These scanners are configured to scan through either a CT scan, MRI or other type of scan an ankle joint of an affected leg as well as an ankle joint of a contralateral leg. The information received into these computers can then be transported into the processing computers140and/or150and then processed and transported over to any one of servers120and130for further information processing.

While the processing and procedures that can be used for creating a talus implant have been shown above, this type of processing can be used to create other implants as well.

FIG.11is a flow chart for the generic process of creating an implant for a joint. For example, an initially injured region is first scanned in step S30. Next, once the region is scanned, the system comprising either a radiologist computer or other physician or medical practitioner can determine which bone(s) primarily need to be replaced in step S31. Next, in step S32the system/practitioner can scan and/or observe the surrounding area. This step can include either nondestructive evaluation through scanning or through actual incision into the joint and visual observation of the joint if necessary. From this additional scan, the system can determine whether adjacent bones which are adjacent to the primarily damaged bone require any additional treatment such as additional implants, caps or other types of surface treatment. Next, in step S34the system can scan the contralateral bone/joint. This scan can be for an uninjured body part on an opposite side of the user's body. For example, if a person injures his or her left index finger such as a broken phalange, the process shown inFIG.11can be applied. For example, the system would first scan the area of injury to determine if a distal, middle or proximal phalange of the left index finger has been damaged. If for example both the distal and the middle phalange of the left index finger have been essentially crushed and/or shattered requiring an implant, then the system can determine in step S31that both the distal and the middle phalange need to be replaced. In step S32, the system can observe the surrounding area such as the proximal phalange to determine if a portion of the proximal phalange has been damaged. If an outer or distal tip of the proximal phalange has been damaged, then in step S33the system can determine that the proximal phalange requires an end treatment requiring a portion of an implant. During this initial scanning phase, the system can obtain dimensions of the damaged bone(s) in the injured region. Next, in step S34the system can scan the contralateral joint/region which in this instance would be a right index finger, particularly the distal, middle and the proximal phalange of the right index finger. From these scanned dimensions, they can be inverted and compared to the affected or injured region. In many cases if the injured region is so damaged that it cannot offer reliable data, only the inverted dimensions of the contralateral bones/joint will be taken. The patient's demographic information and medical history can also be useful to determine whether there should be any additional modifications to the dimensions are necessary. Next, these dimensions can be compared to a pre-set set of dimensions stored in a database in database server120. In this case, the length, and diameter of each of the distal, middle and proximal phalanges of a left index finger would be compared to the existing dimensions taken from the inversion of the dimensions of the contralateral affected area. The best match of the dimensions in the database with the inverted dimensions of the contralateral affected are chosen so that these dimensions can be sent to a processing computer160and eventually onto a printer such as printer170for printing one or more implants.

Thus, this system and process is configured to obtain dimensions of an injured joint, or of the contralateral joint of an injured joint, and then compare these sets of information to information regarding dimensions in a database to determine the best set of dimensions for printing an implant. With greater experience, the database can be populated with many sets of dimensions for different types of patients so that the system can appropriately select the correct set of dimensions for a patient. In addition, the system can provide weighted values of different dimensions to determine which dimension is more indicative of a correct set of dimensions for an implant such as overall length, height, width, and shape. With certain implants length may be more important than height or width. Alternatively, with the case of elongated substantially cylindrical bones such as a phalange, the diameter of a bone may be more important than the length of a bone or vice versa. Furthermore, through pre-set ranges or through previously reported successful implants, the system can determine whether to use the pre-set dimensions of a database or whether to create a new set of dimensions for storage in a database. These new dimensions can be entirely new dimensions which populate a new case for use in the future. For example, if the dimensions of the affected bone or joint area differ by a % amount that is outside of a pre-set range then a new set of dimensions for an implant can be stored in the database rather than having the system rely on an old set of dimensions for use in an implant. This pre-set range can be a difference based upon a pre-set % amount of length, width, height, diameter etc. Some pre-set ranges could be 1%, 0.5%, 2% or any amount of differential up to 3%, 5% or even 10%. Alternatively, the pre-set differences between the measured dimensions and the dimensions that are stored in the database can be based upon a pre-set length, width, height or diameter such as 1 mm, 2 mm or any other type of pre-set dimensions that are set in the system to determine whether there is a suitable match between the measured damaged joint or bone or the inverted dimensions of the contralateral joint or bone and the measurements stored in a database.

Thus, the system is configured to either take a new set of data points for printing an implant or to rely on a library or database of past dimensions for an implant when printing an implant for use in repairing a patient's bone or joint.