Patent Description:
This disclosure is related to systems to facilitate total ankle arthroplasty ("TAA") procedures, and, in particular, patient-specific ankle cutting guide systems.

For patients with damaged or otherwise malformed ankle joints, for example due to arthritis or a bone fracture, TAA, also known as total ankle replacement ("TAR"), is being increasingly performed in lieu of ankle fusion procedures. A TAA procedure may include resecting a portion of the patient's distal tibia and/or a portion of the patient's proximal talus and replacing the resected bone with prosthetic components. The accuracy with which the bone resections are made may play an important role in the success of the entire TAA procedure as well as the correct placement of implant components after the bones are resected. The ability for a surgeon to make accurate cuts may be hampered at least in part due to the small size of the operative area in TAA procedures with relatively little space for visualization and surgical instrumentation. Thus, improvements in apparatus and methods to facilitate TAA procedures are desired. Document <CIT> discloses the closest prior art to the subject-matter of the present invention.

According to one aspect of the disclosure, a device for assisting in performing an ankle arthroplasty on a non-resected bone surface of a tibia includes a posterior surface having a mating surface configured to engage the non-resected bone surface of the tibia in a matching manner on account of a patient-specific nature of the mating surface. The matching manner may register a single relative position of the mating surface relative to the non-resected bone surface of the tibia, and the patient specific nature of the mating surface portion may have been generated in the device prior to the device being brought into contact with the bone surface of the tibia or employed in the arthroplasty. A first guide member may define a transverse cutting instrument guide slot and may have an anterior entrance and a posterior exit. The transverse guide slot may be configured to guide a cutting instrument along a transverse planar guide surface that is substantially orthogonal to a tibial mechanical axis of the tibia when the non-resected tibia surface is engaged to the mating surface in the matching manner. The term "substantially orthogonal" is used because the cut plane may be slightly angled relative to the tibial mechanical axis to accommodate the particular patient's anatomy or to correct a deformity. A second guide member may be coupled to the first guide member. The second guide member may define an angled guide surface angled obliquely to the transverse guide slot. The mating surface may have a first curvature that is curved posteriorly from a central area of the mating surface toward a medial and a lateral edge of the mating surface so that the central area of the mating surface is positioned anterior to the medial and lateral edges of the mating surface.

When in contact with the non-resected bone surface, the first curvature of the mating surface at least partially wraps around the non-resected bone surface in a medial-to-lateral direction. The mating surface may have a second curvature that is curved posteriorly from the central area of the mating surface toward a superior and an inferior edge of the mating surface so that the central area of the mating surface is positioned anterior to the superior and inferior edges of the mating surface. When in contact with the non-resected bone surface, the second curvature of the mating surface at least partially wraps around the non-resected bone surface in a superior-to-inferior direction. The mating surface may include an extension portion that extends both inferior and medial of the first guide member, and medial of the second guide member, and the extension portion may be positioned for contacting a medial malleolus of the patient. The device may include a first cylindrical member defining a first pin hole and a second cylindrical member defining a second pin hole. The first and second pin holes may be sized to receive first and second fastening members therethrough, the first and second cylindrical members positioned superior to the first guide member, although in other embodiments the first and second pin holes may be positioned inferior to the first guide member. The first guide member may define a third pin hole at a medial end of the transverse slot and a fourth pin hole at a lateral end of the transverse slot. The device may include a plurality of openings extending from an anterior surface of the device to the posterior surface of the device so that, when the mating surface is engaged with the non-resected bone surface of the tibia, the tibia is visible through the plurality of openings. The transverse guide slot may be defined between a top wall and a bottom wall, the top and bottom walls each having a plurality of peaks and a plurality of troughs. Each peak of the top wall may be aligned in a superior-to-inferior direction with a corresponding trough in the bottom wall, and each peak of the bottom wall may be aligned in the superior-to-inferior direction with a corresponding trough of the top wall. The first guide member may include a channel extending therethrough for receiving an alignment rod, the channel extending orthogonal to the transverse guide slot. The device may also include a rotational alignment sight. The rotational alignment sight may include a projection and an alignment window. When the device is coupled to the tibia, a desired rotational position of the tibia may be indicated when the projection aligns with the alignment window.

According to a further aspect of the disclosure, a device for assisting in performing an ankle arthroplasty on a non-resected bone surface of a talus includes a paddle member having a first mating surface configured to engage the non-resected bone surface of the talus in a first matching manner on account of a patient-specific nature of the first mating surface. The first matching manner may register a single relative position of the first mating surface relative to the non-resected bone surface of the talus, the patient specific nature of the first mating surface having been generated in the device prior to the device being brought into contact with the bone surface of the talus or employed in the arthroplasty. However, in some embodiments, this paddle member may be omitted. A first guide member may define a transverse cutting instrument guide slot and may have an anterior entrance and a posterior exit, wherein the transverse guide slot is configured to guide a cutting instrument along a transverse planar guide surface that is substantially orthogonal to a tibial mechanical axis of the tibia when the non-resected talus surface is engaged to the mating surface in the first matching manner. Again, the term "substantially orthogonal" is used because the cut plane may be slightly angled relative to the tibial mechanical axis to accommodate the particular patient's anatomy or to correct a deformity. A stabilizer member may have a second mating surface configured to engage the non-resected bone surface of the talus in a second matching manner on account of a patient-specific nature of the second mating surface. The second matching manner may register a single relative position of the second mating surface relative to the non-resected bone surface of the talus, the patient specific nature of the second mating surface having been generated in the device prior to the device being brought into contact with the bone surface of the talus or employed in the arthroplasty. The first guide member may be positioned inferior to the paddle member, and the stabilizer member may be positioned inferior to the first guide member.

The first mating surface of the paddle member may be positioned on a posterior and inferior end of the paddle member. The paddle member may include an angled pin hole extending at an oblique angle to the transverse planar guide surface. The stabilizer member may have a medial wing portion and a lateral wing portion, the second mating surface of the stabilizer member being positioned on the medial and lateral wing portions. The stabilizer member may have a first rail and a second rail each extending in an anterior-to-posterior direction, the second mating surface of the stabilizer member being positioned on inferior surfaces of the first rail and the second rail. The device may include a first cylindrical member defining a first pin hole and a second cylindrical member defining a second pin hole, the first and second pin holes sized to receive first and second fastening members therethrough, the first and second cylindrical members positioned inferior to the first guide member. The first guide member may define a third pin hole at a medial end of the guide slot and a fourth pin hole at a lateral end of the guide slot. The first cylindrical member may be positioned a first distance inferior to the first guide member, and the second cylindrical member may be positioned a second distance inferior to the first guide member, the second distance being greater than the first distance. The first guide member may include a channel extending therethrough for receiving an alignment rod, the channel extending orthogonal to the transverse guide slot. The device may include a first cylindrical member defining a first pin hole and a second cylindrical member defining a second pin hole, the first and second pin holes sized to receive first and second fastening members therethrough, the first and second cylindrical members coupled to the first guide member by an extension member, the extension member including a channel extending therethrough for receiving an alignment rod, the channel extending in an anterior-to-posterior direction parallel to the transverse planar guide surface.

According to another aspect of the disclosure, a device for assisting in performing an ankle arthroplasty on a non-resected bone surface includes a posterior surface having a mating surface configured to engage the non-resected bone surface in a matching manner on account of a patient-specific nature of the mating surface. The matching manner may register a single relative position of the mating surface relative to the non-resected bone surface. The patient specific nature of the mating surface portion may have been generated in the device prior to the device being brought into contact with the bone surface or employed in the arthroplasty. The device may include a cutting instrument guide slot defined by the device and having an anterior entrance and a posterior exit. When the mating surface is engaged to the non-resected bone surface, a center portion of the posterior exit of the guide slot may be positioned a first distance from the non-resected bone surface. The bone surface may be a surface of a tibia, and the guide slot may form a first planar guide surface that is substantially orthogonal to a tibial mechanical axis of the tibia when the non-resected tibia surface is engaged to the mating surface in the matching manner. The device may further define an open viewing window separating the posterior surface into proximal and distal portions. The open viewing window may further separate the posterior surface portion into medial and lateral portions. The device may further include a second planar cutting surface angled obliquely to the guide slot. The anterior entrance of the guide slot may be open at a medial end so that the guide slot freely transitions into the second planar cutting surface. The anterior entrance of the guide slot may be closed at a medial end by a connection portion extending from the planar cutting surface. The device may further include first and second guide holes configured to receive fixation pins through the device, the first and second guide holes each defining axes that are parallel to one another.

According to another embodiment of the disclosure, a device for assisting in performing an ankle arthroplasty on a non-resected bone surface of a tibia includes a posterior surface having a mating surface configured to engage the non-resected bone surface of the tibia in a matching manner on account of a patient-specific nature of the mating surface. The matching manner may register a single relative position of the mating surface relative to the non-resected bone surface of the tibia. The patient specific nature of the mating surface portion may have been generated in the device prior to the device being brought into contact with the bone surface of the tibia or employed in the arthroplasty. A cutting instrument guide slot may be defined by the device and may have an anterior entrance and a posterior exit. The guide slot may form a first planar guide surface that is substantially orthogonal to a tibial mechanical axis of the tibia when the non-resected tibia surface is engaged to the mating surface in the matching manner. A cutting guide member may be adapted to couple to the guide slot, the cutting guide member defining a second planar guide surface angled obliquely to the first planar guide surface. The cutting guide member may be adapted to be hingedly coupled to the guide slot. The cutting guide member may be formed of a metallic material. The cutting guide member may include a hinge portion and a flange portion, the flange portion defining the second planar guide surface. The hinge portion may include a first pin hole extending therethrough. A medial end of the guide slot may define a second pin hole, the first and second pin holes being coaxially aligned when the cutting guide member is coupled to the guide slot.

In the present disclosure, the term proximal generally means closer to the heart and the term distal generally means farther away from the heart. The term posterior means a position towards the rear of the body and the term anterior means a position toward the front of the body. The term superior means a position closer to the head and the term inferior means a position closer to the feet. The term patient-specific as used herein refers to a surface of a device configured to mate with a corresponding anatomical surface in substantially only one position and orientation.

<FIG> illustrates a simplified side view of the bones of the foot and ankle, including the distal tibia <NUM>, the talus <NUM>, and the fibula <NUM>. In one example, the distal tibia <NUM> and proximal talus <NUM> may be arthritic and need replacing, for example with a metal tibial component <NUM> and a metal talar component <NUM>, respectively, with a plastic mobile bearing <NUM> (e.g. ultra-high molecular weight polyethylene) interposed between the metal components. An example of such an implant is shown in <FIG>.

In order to facilitate the surgeon in making accurate resections of the tibia <NUM> and talus <NUM>, resection guides may be used to guide the cutting instrument in a desired fashion. Such cutting guides, described in greater detail below, may be at least partially patient specific. For example, a surgeon may image the patient's tibia <NUM> and talus <NUM> and with the use of specialized software, cutting guides that include bone-contacting surfaces that match (e.g. form a substantial negative of) the topography of the relevant bone may be produced. In this manner, the cutting guides may fit on the corresponding bones in only one (or substantially only one) configuration, helping the surgeon to confirm proper placement. Briefly, computed tomography ("CT") based images may be used to create a 3D model of the patient's anatomy, although other imaging modalities, such as MRI, may be suitable. Other imaging modalities that may be suitable include ultrasound and two-dimensional X-rays that may be morphed into predicted three-dimensional images using statistical shape models, Anatomical alignment can be performed and cutting planes/datum pin placement can be established preoperatively. It should be understood that "datum pin" may refer to a pin that is used in the ankle replacement procedure to place a subsequent instrument called the "datum," with subsequent cut guides being attached to the datum instrument to make chamfer cuts. _Patient specific cutting guides or jigs can then be designed from the established cutting planes and datum axis. With the cutting slots (corresponding to the desired cutting planes) and datum pin holes designed, the patient's anatomy can be used to create a matching surface for the guide to fit into place on one specific patient. A Boolean subtraction can be used to create the matching surface of the patient's anatomy that will align the guide intraoperatively. Alternatively, a matching surface can be "grown" or extrapolated from the patient's anatomy. This grown or extrapolated surface may restrict the cut guide to fit in only one area and orientation on one specific patient creating the intraoperative alignment. The patient-specific bone contacting surfaces of the cutting guides are just one feature of the patient specific cutting guides.

For a typical TAA procedure, two patient-specific cutting guides are designed for each patient, including a tibia guide and a talus guide. One example of a patient-specific tibia guide <NUM> is shown in <FIG>. Tibia guide <NUM> includes an anterior surface <NUM> (<FIG>) and a posterior bone-contacting surface <NUM> (<FIG>). Tibia guide <NUM> is configured to attach to the anterior surface of the patient's tibia <NUM>. The posterior bone-contacting surface <NUM> may be keyed to the geometry of the patient's tibia <NUM> so that tibia guide <NUM> may fit onto the patient's tibia <NUM> in only one position and orientation. In addition, the posterior bone-contacting surface <NUM> may be curved posteriorly from the center toward the medial and lateral edges so that the tibia guide <NUM> at least partially wraps around the tibia <NUM> to increase surface area contact between the tibia guide <NUM> and the tibia <NUM>.

Two pin holes <NUM> and <NUM> extend through both the anterior surface <NUM> and posterior surface <NUM> of the tibia guide <NUM> and are sized and shaped to receive fixation pins, or other suitable fixation means, therethrough to fix the tibia guide <NUM> to the patient's tibia <NUM>. In the illustrated example, pin holes <NUM> and <NUM> are positioned superior to a transverse cutting guide slot <NUM> of the tibia guide <NUM>. Pin hole <NUM> may be positioned on a lateral side of the tibia guide <NUM> and pin hole <NUM> may be positioned on a medial side of the tibia guide <NUM>, with pin holes <NUM> and <NUM> being positioned substantially the same height from cutting guide slot <NUM>. Pin holes <NUM> and <NUM> may be formed in portions of tibia guide <NUM> that extend farther anteriorly than other portions of the anterior surface <NUM> of tibia guide <NUM>, for example in cylindrical or other shaped projections, in order to provide greater surface area for contact between a pin inserted through pin holes <NUM> and <NUM> and tibia guide <NUM>. As is described in greater detail below, pin holes <NUM> and <NUM> may have positions and orientations that correspond to pin hole positions and orientations of a talus guide <NUM> so that the talus guide <NUM> may be slid over the same pins used to hold the tibia guide <NUM> to the patient's tibia <NUM> after the tibia guide <NUM> is removed. Further, pin holes <NUM> and <NUM> may have positions and orientations that correspond to pin hole positions and orientations of a universal, non-patient specific cutting guide so that, during the procedure, the surgeon may choose to switch to a universal cutting guide if he or she so desires.

The cutting guide slot <NUM> may include a first guide portion <NUM> and a second guide portion <NUM>. The first guide portion <NUM> may generally consist of two parallel transverse walls defining a first slot therebetween. This first guide portion <NUM> and corresponding first slot are configured to assist the surgeon in creating a flat transverse cut in the patient's tibia <NUM>. Preferably, the slot <NUM> of the first guide portion <NUM> is substantially planar and, when tibia guide <NUM> is coupled to the tibia <NUM>, the plane of the slot <NUM> is substantially orthogonal to the mechanical axis of the tibia <NUM>. The second guide portion <NUM> may consist of a single wall extending at an oblique angle to the first slot, which may in particular be an obtuse angle. However, in some circumstances it may be suitable for the second guide portion <NUM> to extend perpendicularly relative to the first slot. The second guide portion <NUM> may define a second slot, although in this instance the second slot is generally open because it is bounded on only one side. This second slot may be configured to assist the surgeon in releasing the resected bone from the medial malleolus and/or from the medial side of the tibia, superior to the medial malleolus. The configuration of the first slot being defined by a fully (or nearly fully) enclosed first guide portion <NUM> may facilitate a saw blade or other resection tool being directed in a limited intended manner. The configuration of the second slot being open and bounded only by the second guide portion <NUM> may provide additional freedom of movement that may be necessary for the surgeon to make the cut. Although the second guide portion <NUM> is being illustrated as being open, in other embodiments (including in other tibia guides described herein that include a generally similar second guide portion), the second guide potion <NUM> in some embodiments may be closed (or captured), so that one or both of the cutting slots are enclosed or captured. In addition, it should be understood that tibia guide <NUM> (as well as other tibia guides described herein), need not always be used to resect the medial malleolus, depending on the particular patient and desired surgical procedure.

In addition to defining the first slot, the first guide portion <NUM> may define a first pin hole <NUM> at a first end of the first slot relatively far away from the second guide portion <NUM>. The first guide portion <NUM>, either alone or in combination with the second guide portion <NUM>, may define a second pin hole <NUM> on the opposite side of the first slot from the first pin hole <NUM>. The pin holes <NUM> and <NUM> may be configured to receive pins, similar to as described above in connection with pin holes <NUM> and <NUM>. Pins extending through pin holes <NUM> and <NUM> into the patient's tibia <NUM> may help guide the saw blade, or other cutting tool, as it is inserted through the first and/or second slots and into the patient's tibia <NUM>. In addition, the pins extending through pin holes <NUM> and <NUM> may help protect soft tissue, hard tissue, and portions of the cutting guides from being unintentionally cut or otherwise damaged. Further, it should be noted that pin holes <NUM> and <NUM>, and/or pins extending through these pin holes, may be calibrated with the tibia guide <NUM>, based on information from the prior imaging (e.g. CT scan) so that the pins cannot be over inserted. It should be understood that, for any of the cutting guides described herein, the tool guided by the cutting guide may be any type of saw, including oscillating saws, reciprocating saws, and Precision saws offered by Stryker Corporation.

Still referring to <FIG>, the tibia cutting guide <NUM> may also include two additional pin holes <NUM> and <NUM> inferior to first guide portion <NUM>. Pin holes <NUM> and <NUM> are preferably positioned a distance from second guide portion <NUM> so as to avoid any possible interference with the second cut along the second guide portion <NUM>. Although standard pins may be used with pin holes <NUM> and <NUM> to provide additional attachment security of tibia cutting guide <NUM> to the patient's tibia <NUM>, it is envisioned that threaded pins may be used through pin holes <NUM> and <NUM>. By using threaded pins to help attach the tibia guide <NUM> to the patient's tibia <NUM>, after both tibial cuts are made, pulling the threaded pins may help remove the portion of the patient's tibia <NUM> that has been cut completely free from the remainder of the patient's tibia <NUM>.

The tibia guide <NUM> may also include a window <NUM>. Window <NUM> may facilitate the surgeon in better visualizing the patient's tibia <NUM> and checking proper fitting between the tibia guide <NUM> and the patient's tibia <NUM>. Window <NUM> may generally be defined by a plurality of protruding walls connecting pin hole <NUM> to pin hole <NUM>, and pin holes <NUM> and <NUM> to the superior wall of first guide portion <NUM>. As illustrated, window <NUM> is generally rectangular, although other window shapes may be suitable. Tibia guide <NUM> is illustrated positioned on the tibia <NUM> of a patient, with pins removed for clarity, in <FIG>. It should be noted that pin holes <NUM> and <NUM> may extend along axes that are parallel to one another, pin holes <NUM> and <NUM> may extend along axes that are parallel to one another, and pin holes <NUM>, <NUM> may extend along axes that are parallel to one another.

Now referring to <FIG>, an example of a talus guide <NUM> is illustrated. Talus guide <NUM> includes an anterior surface <NUM> (<FIG>) and a posterior bone-contacting surface <NUM> (<FIG>). Talus guide <NUM> may include an upper portion <NUM> configured to attach to the anterior surface of the patient's tibia <NUM> and a lower portion <NUM> configured to attach to the anterior surface of the patient's talus <NUM>. The posterior bone-contacting surfaces <NUM> of the upper portion <NUM> and lower portion <NUM> may be keyed to the geometry of the patient's tibia <NUM> and talus <NUM>, respectively, so that talus guide <NUM> may fit onto the patient's tibia <NUM> and talus <NUM> in only a single position and orientation. In addition, the posterior bone-contacting surfaces <NUM> may be curved posteriorly from the center toward the medial and lateral edges so that the talus guide <NUM> at least partially wraps around the tibia <NUM> and talus <NUM> to increase surface area contact between the talus guide <NUM> and the tibia <NUM> and talus <NUM>.

Two pin holes <NUM> and <NUM> extend through both the anterior surfaces <NUM> and posterior surfaces <NUM> of the upper portion <NUM> of the talus guide <NUM> and are sized and shaped to receive fixation pins, or other suitable fixation means, therethrough to fix the upper portion <NUM> of the talus guide <NUM> to the patient's tibia <NUM>. In the illustrated example, pin holes <NUM> and <NUM> are positioned superior to a transverse cutting guide slot <NUM> of the talus guide <NUM>. Pin hole <NUM> and may be positioned on a lateral side of the talus guide <NUM> and pin hole <NUM> may be positioned on a medial side of the talus guide <NUM>, with pin holes <NUM> and <NUM> being positioned substantially the same height from transverse slot <NUM>. As best seen in <FIG>, pin holes <NUM> and <NUM> may be formed in portions of talus guide <NUM> that extend farther anteriorly than other portions of the anterior surface <NUM> of talus guide <NUM>, for example in cylindrical or other shaped projections, in order to provide greater surface area for contact between a pin inserted through pin holes <NUM> and <NUM> and talus guide <NUM>. Pin holes <NUM> and <NUM> may have the same size, position, and orientation with respect to one another as pin holes <NUM> and <NUM> of tibia guide <NUM> so that, after use and removal of the tibia guide <NUM>, the pin holes <NUM> and <NUM> of the talus guide <NUM> may be slipped over the pins that were previously used with pin holes <NUM> and <NUM> of the tibia guide <NUM>.

The transverse slot <NUM> may be defined by a guide portion generally consisting of two parallel walls defining the transverse slot <NUM> therebetween. Transverse slot <NUM> may be configured to assist the surgeon in creating a flat transverse cut in the patient's talus <NUM>. The transverse slot <NUM> may be fully enclosed to facilitate a saw blade or other resection tool being directed in a limited intended manner. The parallel walls defining the transverse slot <NUM> may also define a first pin hole <NUM> on a lateral side of the talus guide <NUM> and a second pin hole <NUM> on a medial side of the talus guide <NUM>. The pin holes <NUM> and <NUM> may be configured to receive pins, similar to as described above in connection with pin holes <NUM> and <NUM>. Pins extending through pin holes <NUM> and <NUM> and into the patient's talus <NUM> may help guide the saw blade, or other cutting tool, as it is inserted through the transverse cutting slot <NUM> and into the patient's talus <NUM>. In addition, the pins extending through pin holes <NUM> and <NUM> may help protect soft tissue, hard tissue, and portions of the cutting guide from being unintentionally cut or otherwise damaged.

The talus guide <NUM> may include a protrusion in the form of a tongue or paddle <NUM> extending posteriorly from an area of the talus guide <NUM> between the upper portion <NUM> and lower portion <NUM> and superior to the transverse slot <NUM>. The paddle <NUM> may be configured for insertion between the resected surface of the distal tibia <NUM> and the unresected proximal surface of the talus <NUM>. Paddle <NUM> is preferably sized and shaped to provide additional surface area contact between talus guide <NUM> and the tibia <NUM> and talus <NUM>, which may better support the foot after the tibia <NUM> has been cut. This support may be particularly useful during the step of resecting the talus <NUM> with a blade or other cutting tool through transverse slot <NUM>.

Prior to resecting the talus <NUM>, the patient's foot may be rotated so that the talus <NUM> is in proper contact with the lower portion <NUM> of talus guide <NUM>. Once the talus <NUM> is in the proper position, the surgeon may insert pins through pin holes <NUM> and <NUM> and into the properly positioned talus <NUM>. Pin holes <NUM> and <NUM> are positioned inferiorly of the transverse cutting slot <NUM>. The talus guide <NUM> may also include a window <NUM> similar to window <NUM>. Window <NUM> may facilitate the surgeon in better visualizing proper contact between the talus guide <NUM> and the patient's tibia <NUM> and talus <NUM>. Window <NUM> may generally be defined by a plurality of protruding walls connecting pin hole <NUM> to pin hole <NUM>, and pin holes <NUM> and <NUM> to the superior wall that defines the transverse slot <NUM>. As illustrated, window <NUM> is generally rectangular, although other window shapes may be suitable.

Talus guide <NUM> may further include an angled pin hole <NUM> to guide the datum pin into place so the surgeon can attach the existing datum pin cutting guides. In an exemplary TAA procedure, prior to inserting the datum pin, pins in holes <NUM> and <NUM> are removed, after the talus <NUM> is resected, and the patient's foot is plantar flexed to provide the desired insertion position of the datum pin. After the datum pin is in place, the tibia guide <NUM> and talus guide <NUM> may be discarded and the TAA procedure continued. Talus guide <NUM> is illustrated positioned on the tibia <NUM> and talus <NUM> of a patient, with pins removed for clarity, in <FIG>. Other steps of a TAA procedure that may be used with the cutting guides described herein, including the steps leading up to the use of the guides and the steps following the use of the guides, are provided in <CIT>.

<FIG> illustrates an alternate version of talus guide <NUM>' in which the upper portion of talus guide <NUM>' does not include a patient-specific tibia contacting surface. The remaining components of talus guide <NUM>', including pin holes <NUM>', <NUM>', <NUM>', <NUM>', window <NUM>', angled pin hole <NUM>', transverse slot <NUM>', and the pin holes <NUM>' and <NUM>' at the opposite ends of the transverse slot <NUM>', are identical to the corresponding features of talus guide <NUM>.

<FIG> illustrate a tibia guide <NUM> that is mostly similar to tibia guide <NUM> with certain differences. It should be noted that the illustrated tibia guide <NUM> is for a right foot, whereas the illustrated tibia guide <NUM> is for a left foot. Further, for purposes of illustration, certain portions of tibia guide <NUM> are omitted from view, such as the patient specific surfaces and other surfaces that are not part of the cutting slots or pin holes (e.g. the surfaces corresponding to anterior surface <NUM> and posterior surface <NUM> of tibia guide <NUM> are omitted from the illustration of tibia guide <NUM>). As shown in <FIG>, tibia guide <NUM> includes two superior pin holes <NUM>, <NUM> and two inferior pin holes <NUM>, <NUM> with a first cutting guide portion <NUM> and window <NUM> positioned therebetween. Similar to tibia guide <NUM>, first cutting guide portion <NUM> defines a transverse slot <NUM> with a first pin hole <NUM> and a second pin hole <NUM> at opposite ends of the transverse slot <NUM>. Also similar to tibia guide <NUM>, tibia guide <NUM> includes a second guide portion <NUM> extending obliquely or orthogonally to the transverse cutting slot <NUM> to assist a surgeon in resecting the medial malleolus. The portions of tibia guide <NUM> described above may have the same relative positioning and orientation with respect to the corresponding features of tibia guide <NUM>, with the exception that tibia guide <NUM> is for a right foot whereas tibia guide <NUM> is for a left foot.

There are a number of differences between tibia guide <NUM> and tibia guide <NUM>. For example, whereas the transition from the first cutting guide portion <NUM> to second cutting guide portion <NUM> is completely open in tibia guide <NUM>, the transition from first cutting guide portion <NUM> to second cutting guide portion <NUM> of tibia guide <NUM> is partially closed. In particular, a connecting portion 221a connects first cutting guide portion <NUM> to second cutting guide portion <NUM> so that pin hole <NUM> is fully enclosed at the anterior end of the guide <NUM>. As illustrated, connecting portion 221a does not extend the full anterior to posterior length of the transition between first cutting guide portion <NUM> and second cutting guide portion <NUM>. Although the exact length which connecting portion 221a extends in an anterior to posterior direction along the transition between first cutting guide portion <NUM> and second cutting guide portion <NUM> may be designed as desired by surgeon or other medical personnel, preferably the length is less than one half, more preferably less than one third, and most preferably one fourth or less the anterior to posterior length of the second cutting guide portion <NUM>. With this closed configuration provided by the connection section 221a, additional strength and rigidity is provided to the transition between the first cutting guide portion <NUM> and the second cutting guide portion <NUM>. However, the short length of the connecting portion 221a allows the surgeon to resect a significant portion of the medial malleolus. For example, the portion of the medial malleolus posterior to the connecting portion 221a may be resected by guiding a resecting blade or other cutting tool along second cutting guide portion <NUM>, and guiding a cutting portion of the cutting tool to a position posterior to the connecting portion 221a. If connecting portion 221a extended the entire length of the second cutting guide portion <NUM>, a corresponding portion of the medial malleolus would not be easily accessible and it also could be more likely that the tibia guide <NUM> would be unintentionally cut. It should be understood that after making the transverse cut through cutting slot <NUM> and the medial malleolus cut along second guide portion <NUM>, a small portion of bone may need to be manually resected after the cutting guide is removed to complete the continuity between the two cuts.

Another difference between tibia guide <NUM> and tibia guide <NUM> is that tibia guide <NUM> includes an offset distance between the transverse cutting slot <NUM> and the tibia <NUM> when the tibia guide <NUM> is coupled to the tibia <NUM>. <FIG> illustrates a sectional view of tibia guide <NUM> coupled to tibia <NUM> along a plane orthogonal to the longitudinal axis of the tibia <NUM>. <FIG> illustrates a sectional view of the tibia guide <NUM> coupled to tibia <NUM> along a plane through the longitudinal axis of the tibia <NUM> extending in an anterior-to-posterior direction. For clarity of illustration, most portions of tibia guide <NUM> that do not form any part of transverse cutting slot <NUM> are omitted from <FIG>. As shown in <FIG>, the posterior surfaces of the walls of first guide portion <NUM> that define cutting slot <NUM> are offset a distance D<NUM> from the corresponding surface of the tibia <NUM> when the tibia guide <NUM> is coupled to the tibia <NUM> in an operative condition. In other words, the majority of a center portion of the posterior surface of the first guide portion <NUM> that defines cutting slot <NUM> extends anteriorly a distance of D<NUM> compared to the posterior bone-contacting surfaces of tibia guide <NUM> immediately adjacent the medial and lateral ends of cutting slot <NUM>. This offset distance D<NUM> reduces the amount of debris resulting from the resection blade (or other cutting tool) contacting the tibia guide <NUM> near the point where the blade enters the tibia <NUM>.

<FIG> illustrate a tibia guide <NUM> that is mostly similar to tibia guide <NUM> with one difference. For purposes of illustration, certain portions of tibia guide <NUM> are omitted from view, such as the patient specific surfaces and other surfaces that are not part of the cutting slots or pin holes (e.g. the surfaces corresponding to anterior surface <NUM> and posterior surface <NUM> of tibia guide <NUM> are omitted from the illustration of tibia guide <NUM>). As shown in <FIG>, tibia guide <NUM> includes two superior pin holes <NUM>, <NUM> and two inferior pin holes (omitted from <FIG>) with a first cutting guide portion <NUM> and window <NUM> positioned therebetween. Similar to tibia guide <NUM>, first cutting guide portion <NUM> defines a transverse slot <NUM> with a first pin hole <NUM> and a second pin hole <NUM> at opposite ends of the transverse slot <NUM>.

Tibia guide <NUM> does not include a second cutting guide portion integral with the tibia guide <NUM> as shown in tibia guides <NUM> and <NUM>. Rather, a second guide portion <NUM> is provided separately and is attachable to tibia guide <NUM> via pin hole <NUM>. For example, second guide portion <NUM> may be a metallic hinge type device that may be sterilized and reused for multiple tibia guides <NUM> corresponding to different patients. In particular, and as best shown in <FIG>, second guide portion <NUM> may include a hinge portion 324a and a flange portion 324b. Hinge portion 324a may include a connecting portion that extends into pin hole <NUM> to couple second guide portion <NUM> to tibia guide <NUM>. Preferably, the portion of hinge portion 324a inserted into pin hole <NUM> does not extend a distance greater than connecting portion 321a (see <FIG>). Hinge portion 324a includes a pin hole that is preferably coaxial with pin hole <NUM> when connected to tibia guide <NUM>. With this configuration, a pin may be inserted through both hinge portion 324a and pin hole <NUM> to secure the tibia guide <NUM> to the tibia <NUM>. Alternatively, hinge portion 324a may be coupled to tibia guide <NUM> by a pin inserted through both the hinge portion 324a and pin hole <NUM>, without any portion of hinge portion 324a extending into pin hole <NUM>. Using a second guide portion <NUM> that is separate from tibia guide <NUM> may provide a number of benefits. First, flange 324b, which is intended to guide a saw blade along a cutting path through the medial malleolus, may be positioned at different angles with respect to the transverse cutting slot <NUM> to give additional freedom to the surgeon. Second, because second cutting guide <NUM> is made from a material that is sterilizeable, such as a metal suitable for use in surgery, a single second cutting guide <NUM> may be re-used through multiple procedures, reducing the complexity of designing the remainder of the patient specific tibia guide <NUM> and correspondingly reducing the costs of producing the tibia guide <NUM>. Third, the use of a harder material such as metal may reduce the likelihood that the cutting saw unintentionally cuts into flange portion 324b as the flange portion 324b guides the direction and position of the saw blade.

Although the above-described talus guides provide for a single transverse cut, other talus guides may provide for additional cuts. For example, a two-stage talus guide system may provide for a transverse cut of the proximal talus <NUM> and medial and/or lateral cuts of the talus <NUM>. For example, a first talus guide <NUM> of a two-part talus guide system is illustrated in <FIG>, which may be used after a tibia guide is used to create desired cuts in the distal tibia <NUM>. <FIG> illustrate various views of a tibia <NUM> and talus <NUM> with the first talus guide <NUM> coupled thereto, after tibial cuts have been made but before any talus cuts have been made. First talus guide <NUM> includes an anterior surface <NUM> and a posterior bone-contacting surface (not labelled in the figures). First talus guide <NUM> may include an upper portion <NUM> configured to attach to the anterior surface of the patient's tibia <NUM> and a lower portion <NUM> configured to attach to the anterior surface of the patient's talus <NUM>. The posterior bone-contacting surfaces of the upper portion <NUM> and lower portion <NUM> may be keyed to the geometry of the patient's tibia <NUM> and talus <NUM>, respectively, so that tibia guide <NUM> may fit onto the patient's tibia <NUM> and talus <NUM> in only a single position and orientation.

Two pin holes <NUM> and <NUM> extend through both the anterior surface <NUM> and the posterior surfaces of the upper portion <NUM> of the first talus guide <NUM> and are sized and shaped to receive fixation pins, or other suitable fixation means, therethrough to fix the upper portion <NUM> of the talus guide <NUM> to the patient's tibia <NUM>. Preferably, pin holes <NUM> and <NUM> and positioned to correspond with pin holes of a corresponding tibia guide so that pins previously used to couple a tibia guide to tibia <NUM> can be used without removal to couple the first talus guide <NUM> to the tibia <NUM>. In the illustrated example, pin holes <NUM> and <NUM> are positioned superior to a transverse cutting guide slot <NUM> of the first talus guide <NUM>. Pin hole <NUM> and may be positioned on a lateral side of the first talus guide <NUM> and pin hole <NUM> may be positioned on a medial side of the first talus guide <NUM>, with pin holes <NUM> and <NUM> being positioned substantially the same height from transverse slot <NUM>.

The transverse slot <NUM> may be defined by a guide portion generally consisting of two parallel walls defining the transverse slot <NUM> therebetween. Transverse slot <NUM> may be configured to assist the surgeon in creating a flat transverse cut in the patient's proximal talus <NUM>. The transverse slot <NUM> may be fully enclosed to facilitate a saw blade or other resection tool being directed in a limited intended manner. The parallel walls defining the transverse slot <NUM> may also define a first pin hole <NUM> on a lateral side of the first talus guide <NUM> and a second pin hole <NUM> on a medial side of the first talus guide <NUM>. The pin holes <NUM> and <NUM> may be configured to receive pins, similar to as described above in connection with pin holes <NUM> and <NUM>. Pins extending through pin holes <NUM> and <NUM> and into the patient's talus <NUM> may help guide the saw blade, or other cutting tool, as it is inserted through the transverse cutting slot <NUM> and into the patient's talus <NUM>. In addition, the pins extending through pin holes <NUM> and <NUM> may help protect soft tissue, hard tissue, and portions of the cutting guide from being unintentionally cut or otherwise damaged.

Similar to other talus guides described herein, first talus guide <NUM> may include a protrusion in the form of a tongue or paddle <NUM> extending posteriorly from an area of the first talus guide <NUM> between the upper portion <NUM> and lower portion <NUM> and superior to the transverse slot <NUM> (best shown in <FIG>). The paddle <NUM> may be configured for insertion between the resected surface of the distal tibia <NUM> and the unresected proximal surface of the talus <NUM>. Paddle <NUM> is preferably sized and shaped to provide additional surface area contact between first talus guide <NUM> and the tibia <NUM> and talus <NUM>, which may better support the foot after the tibia <NUM> has been cut.

Prior to resecting the talus <NUM>, the patient's foot may be rotated so that the talus <NUM> is in proper contact with the lower portion <NUM> of first talus guide <NUM>. Once the talus <NUM> is in the proper position, the surgeon may insert pins through pin holes <NUM> and <NUM> and into the properly positioned talus <NUM>. Pin holes <NUM> and <NUM> are positioned inferiorly of the transverse cutting slot <NUM>. The transverse cut in the talus <NUM> may then be made with the guidance of transverse cutting slot <NUM>.

After the first talus guide <NUM> is used to create the transverse cut in the talus <NUM>, the first talus guide <NUM> may be removed. Pins in the bone may also be removed, with the exception of pins previously passing through pin holes <NUM> and <NUM>, which may be left in place. <FIG> illustrates a second talus guide <NUM> for use in creating medial and lateral cuts in the talus <NUM> after the transverse cut is made using the first talus guide <NUM>. <FIG> illustrate the second talus guide <NUM> coupled to the tibia <NUM> and talus <NUM> of the patient after the tibial cuts and the transverse talus cut have been made, but prior to the medial and lateral talus cuts being made. <FIG> illustrate the second talus guide <NUM> coupled to the tibia <NUM> and/or talus <NUM> of the patient after the medial and lateral talus cuts have been made. It should be understood that talus guide <NUM> (as well as other talus guides described herein) may be coupled only to the talus <NUM>, or may be coupled to both the tibia <NUM> and the talus <NUM>.

Second talus guide <NUM> may include a central body portion <NUM>, a lateral body portion <NUM>, and a medial body portion <NUM>. The lateral body portion <NUM> may include a lateral cutting slot <NUM> extending at a slight angle to the mechanical axis of the tibia. The lateral cutting slot <NUM> may be defined by two substantially parallel walls and form a pin hole <NUM> at an inferior end of the lateral cutting slot <NUM>. Similarly, the medial body portion <NUM> may include a medial cutting slot <NUM> extending at a slight angle to the mechanical axis of the tibia. The medial cutting slot <NUM> may be defined by two substantially parallel walls and form a pin hole <NUM> at an inferior end of the medial cutting slot <NUM>. Both the lateral cutting slot <NUM> and the medial cutting slot <NUM> may be bounded at a superior end by a portion of the corresponding lateral body portion <NUM> and medial body portion <NUM>. These superior connections may provide additional stability as a blade or other cutting tool is moved through the lateral cutting slot <NUM> and media cutting slot <NUM>.

Pin holes <NUM> and <NUM> may correspond in size and position to pin holes <NUM> and <NUM> of the first talus guide <NUM>, so that second talus guide <NUM> may be slipped over the pins in the bone previously passing through pin holes <NUM> and <NUM>. In addition, one or both walls of lateral body portion <NUM> and the medial body portion <NUM> may extend superiorly of the central body portion <NUM>, with the superior extensions adapted to fit into the pin holes created in the bone previously from pins passing through pin holes <NUM>. <NUM> of the first talus guide <NUM>. As best seen in <FIG> and <FIG>, second talus guide <NUM> may also include a protrusion <NUM> in the form of a tongue similar in form and purpose to protrusion <NUM>. However, protrusion <NUM> may have flat superior and inferior surfaces, as second talus guide <NUM> is adapted for use after the distal tibia <NUM> has been resected and the proximal talus <NUM> has also been resected. With the protrusion <NUM> inserted between the resected surfaces of the distal tibia <NUM> and proximal talus <NUM>, and with pin holes <NUM> and <NUM> inserted over the pins previously used for the first talus guide <NUM>, a user may guide a cutting blade or other cutting tool through lateral cutting slot <NUM> and medial cutting slot <NUM> to create the medial and lateral cuts of the talus <NUM>, as shown in <FIG>. After the tibial cuts and talus cuts have been made, the ankle arthroplasty procedure may continue and the implant components fixed to the bones as desired.

<FIG> show various views of another example of a patient-specific tibia guide <NUM>, with <FIG> showing the tibia guide coupled to the distal tibia of a patient. However, it should be understood that tibia guide <NUM> shown in <FIG> is for a left ankle, whereas the tibia guide of <FIG> is for a right ankle, which may include identical but mirrored features. Tibia guide <NUM> may have various features similar to other tibia guides described herein, including tibia guide <NUM>. For example, tibia guide <NUM> includes an anterior surface <NUM> and a posterior bone-contacting surface <NUM>. Tibia guide <NUM> is configured to attach to the anterior surface of the patient's tibia <NUM>. The posterior bone-contacting surface <NUM> may be keyed to the geometry of the patient's tibia <NUM> so that tibia guide <NUM> may fit onto the patient's tibia <NUM> in only one (or substantially only one) position and orientation. In addition, the posterior bone-contacting surface <NUM> may be curved posteriorly from the center toward the medial and lateral edges so that the tibia guide <NUM> at least partially wraps around the tibia <NUM> to increase surface area contact between the tibia guide <NUM> and the tibia <NUM> in the medial-to-lateral direction. Still further, the posterior bone-contacting surface <NUM> may be curved posteriorly from the center toward the superior and inferior edges so that the tibia guide <NUM> at least partially wraps around the tibia <NUM> to increase surface area contact between the tibia guide <NUM> and the tibia <NUM> in the superior-to-inferior direction. As in other embodiments described herein, posterior bone-contacting surface <NUM> may include a portion that extends medial of and inferior to the transverse cutting guide for placement on the patient's medial malleolus which may further help stabilize the guide.

Two pin holes <NUM> and <NUM> extend through both the anterior surface <NUM> and posterior surface <NUM> of the tibia guide <NUM> and are sized and shaped to receive fixation pins, or other suitable fixation means, therethrough to fix the tibia guide <NUM> to the patient's tibia <NUM>. In the illustrated example, pin holes <NUM> and <NUM> are positioned superior to a transverse cutting guide slot <NUM> of the tibia guide <NUM>. Pin hole <NUM> may be positioned on a medial side of the tibia guide <NUM> and pin hole <NUM> may be positioned on a lateral side of the tibia guide <NUM>, with pin holes <NUM> and <NUM> being positioned substantially the same height from cutting guide slot <NUM>. In the illustrated embodiment, pin holes <NUM> and <NUM> are positioned just superior of cutting guide slot <NUM>. Pin holes <NUM> and <NUM> may be formed in portions of tibia guide <NUM> that extend farther anteriorly than other portions of the anterior surface <NUM> of tibia guide <NUM>, for example in cylindrical or other shaped projections, in order to provide greater surface area for contact between pins inserted through pin holes <NUM> and <NUM> and tibia guide <NUM>. Pin holes <NUM> and <NUM> may have positions and orientations that correspond to pin hole positions and orientations of a talus guide <NUM> so that the talus guide <NUM> may be slid over the same pins used to hold the tibia guide <NUM> to the patient's tibia <NUM>. Further, pin holes <NUM> and <NUM> may have positions and orientations that correspond to holes in the tibia implant so that, when the holes are drilled out of the tibia <NUM> for implantation of the tibia implant, no holes remain in the bone from use of the tibia guide <NUM> or the talus guide <NUM>.

Tibia guide <NUM> may include two additional pin holes <NUM> and <NUM>. Pin hole <NUM> may be positioned on a medial side of the guide and pin hole <NUM> may be positioned on a lateral side of the guide, with both pin holes <NUM> and <NUM> being positioned near a superior or top end of the guide. Pin holes <NUM> and <NUM> may be defined within cylindrical projections generally similar to pin holes <NUM> and <NUM>. However, pin holes <NUM> and <NUM> may have trajectories that are slightly different from the trajectories of pin holes <NUM> and <NUM>. For example, the trajectories of the pin holes <NUM> and <NUM> may be about five degrees off the trajectories of the pin holes <NUM> and <NUM>. Pin holes <NUM> and <NUM> may be referred to as contingency or "bailout" holes with pin holes <NUM> and <NUM> only intended for use with a universal cutting guide instead of the patient-specific tibia guide <NUM> and talus guide <NUM>. In other words, if a surgeon decides that the tibia guide <NUM> should not be used for any reason, pins may be passed through pin holes <NUM> and <NUM> into the tibia <NUM>, the tibia guide <NUM> may be removed by sliding the guide off the pins, and a traditional universal (i.e. non-patient specific) guide with holes corresponding to the position of pin holes <NUM> and <NUM> may be used to complete the procedure. It should be understood that, even if these "bailout" holes are used, talus guide <NUM> (described in greater detail below) may still be used, or otherwise alternative non-patient specific instruments may be used for resecting the talus <NUM>.

The tibia guide <NUM> may also include one or more visualization windows <NUM>. Windows <NUM> may facilitate the surgeon in better visualizing the patient's tibia <NUM> and checking proper fitting between the tibia guide <NUM> and the patient's tibia <NUM>. In the illustrated embodiment, windows <NUM> may be in the form of a plurality of cut-outs or other apertures in the portion of tibia guide <NUM> contoured to the patient's bone contours, and the cut-outs may extend from the anterior surface <NUM> to the posterior surface <NUM>. In the illustrated embodiment, windows <NUM> include a first group of windows on a lateral side of the tibia guide <NUM> and a second group of windows on the medial side of the tibia guide. The windows <NUM> may include a plurality of hexagonal shaped cut-outs, as well as other shaped cut-outs, such as substantially rectangular cut-outs extending from an area near cutting slot <NUM> to the superior surface of the tibia guide, as well as a plurality of five-sided cut-outs positioned between the hexagonal and rectangular cut-outs. However, it should be understood that other shapes or other groups of shapes may be suitable. In particular, any shaped cut-outs that provide for good visibility while leaving enough structure to maintain structural integrity and rigidity of the tibia guide <NUM> may be suitable in place of the specific embodiment shown.

A cutting guide <NUM> may include a first guide portion <NUM> and a second guide portion <NUM>, which may be substantially similar to the cutting guide slot <NUM> of <FIG>. The first guide portion <NUM> may generally consist of two parallel transverse walls defining a first slot therebetween. This first guide portion <NUM> and corresponding first slot are configured to assist the surgeon in creating a flat transverse cut in the patient's tibia <NUM>. Preferably, the slot of the first guide portion <NUM> is substantially planar and, when tibia guide <NUM> is coupled to the tibia <NUM>, the plane of the slot <NUM> is substantially orthogonal to the mechanical axis of the tibia <NUM>. The second guide portion <NUM> may consist of a single wall extending at an oblique angle to the first slot <NUM>, which may in particular be an obtuse angle. However, in some circumstances it may be suitable for the second guide portion <NUM> to extend perpendicularly relative to the first slot. The second guide portion <NUM> may define a second slot, although in this instance the second slot is generally open because it is bounded on only one side. This second slot may be configured to assist the surgeon in releasing the resected bone from the medial malleolus and/or from the medial side of the tibia, superior to the medial malleolus. The configuration of the first slot being defined by a fully (or nearly fully) enclosed first guide portion <NUM> may facilitate a saw blade or other resection tool being directed in a limited intended manner. The configuration of the second slot being open and bounded only by the second guide portion <NUM> may provide additional freedom of movement that may be necessary for the surgeon to make the cut. Although the first cutting guide portion <NUM> is shown as a slot that is substantially closed, the cutting guide portion may take other forms described above in connection with other embodiments of tibia guides.

In addition to defining the first slot, the first guide portion <NUM> may define a first pin hole <NUM> at a first end of the first slot relatively near the second guide portion <NUM>. The first guide portion <NUM> may define a second pin hole <NUM> on the opposite side of the first slot from the first pin hole <NUM>. The pin holes <NUM> and <NUM> may be configured to receive pins, similar to as described above in connection with pin holes <NUM> and <NUM>. Pins extending through pin holes <NUM> and <NUM> into the patient's tibia <NUM> may help guide the saw blade, or other cutting tool, as it is inserted through the first and/or second slots and into the patient's tibia <NUM>. In addition, the pins extending through pin holes <NUM> and <NUM> may help protect soft tissue, hard tissue, and portions of the cutting guides from being unintentionally cut or otherwise damaged. Further, it should be noted that pin holes <NUM> and <NUM>, and/or pins extending through these pin holes, may be calibrated with the tibia guide <NUM>, based on information from the prior imaging (e.g. CT scan) so that the pins cannot be over inserted.

Tibia guide <NUM> may include an alignment hole <NUM> adapted to receive an alignment rod therethrough. Alignment hole <NUM> is best shown in <FIG>, <FIG>, and <FIG>. Alignment hole <NUM> may extend from the superior end of tibia guide <NUM> and to or through first guide portion <NUM>, and is preferably orthogonal to the transverse cutting slot defined by the first guide portion <NUM>. With this configuration, an alignment rod may be passed through alignment hole <NUM> to check for desired alignment of the tibia guide <NUM> to the tibia <NUM>, as shown in <FIG>. Tibia guide <NUM> may also include one or more fixation blocks, <NUM>, <NUM>, which may be assist in fixation of the tibia guide <NUM> during manufacturing operations.

<FIG> show various views of another example of a patient-specific talus guide <NUM>, with <FIG> showing the talus guide coupled to the talus <NUM> of a patient. However, it should be understood that talus guide <NUM> shown in <FIG> is for a left ankle, whereas the talus guide of <FIG> is for a right ankle, which may include identical but mirrored features. Talus guide <NUM> may have various features similar to other talus guides described herein, including talus guide <NUM> and <NUM>. For example, talus guide <NUM> may include an anterior surface <NUM> and one or more posterior bone-contacting surfaces <NUM> described in greater detail below. Talus guide <NUM> may include an upper portion <NUM> configured to attach to the anterior surface of the patient's tibia <NUM> and a lower portion <NUM> configured to attach to the anterior surface of the patient's talus <NUM>. The posterior bone-contacting surfaces <NUM> of the upper portion <NUM> and lower portion <NUM> may be keyed to the geometry of the patient's tibia <NUM> and talus <NUM>, respectively, so that talus guide <NUM> may fit onto the patient's tibia <NUM> and talus <NUM> in only (or substantially only) a single position and orientation, as described in greater detail below. As with other talus guides described herein, talus guide <NUM> may be coupled to the talus <NUM> only, or to both the tibia <NUM> and the talus <NUM>, with any of the contact areas optionally being patient-specific and configured to fit in only one or substantially only one orientation.

Two pin holes <NUM> and <NUM> may extend through both the anterior surface <NUM> and a posterior surface <NUM> of the upper portion <NUM> of the talus guide <NUM> and are sized and shaped to receive fixation pins, or other suitable fixation means, therethrough to fix the upper portion <NUM> of the talus guide <NUM> to the patient's tibia <NUM>. In the illustrated example, pin holes <NUM> and <NUM> are positioned superior to a transverse cutting guide slot <NUM> of the talus guide <NUM>. Pin hole <NUM> and may be positioned on a medial side of the talus guide <NUM> and pin hole <NUM> may be positioned on a lateral side of the talus guide <NUM>, with pin holes <NUM> and <NUM> being positioned substantially the same height from transverse slot <NUM>. As best seen in <FIG>, pin holes <NUM> and <NUM> may be defined by cylindrical or other shaped projections, in order to provide greater surface area for contact between a pin inserted through pin holes <NUM> and <NUM> and talus guide <NUM>. Pin holes <NUM> and <NUM> may have the same size, position, and orientation with respect to one another as pin holes <NUM> and <NUM> of tibia guide <NUM> so that, after use and removal of the tibia guide <NUM>, the pin holes <NUM> and <NUM> of the talus guide <NUM> may be slipped over the pins that were previously used with pin holes <NUM> and <NUM> of the tibia guide <NUM>.

The transverse slot <NUM> may be defined by a guide portion generally consisting of two parallel walls defining the transverse slot <NUM> therebetween. Transverse slot <NUM> may be configured to assist the surgeon in creating a flat transverse cut in the patient's talus <NUM>. The transverse slot <NUM> may be fully enclosed to facilitate a saw blade or other resection tool being directed in a limited intended manner. The parallel walls defining the transverse slot <NUM> may also define a first pin hole <NUM> on a medial side of the talus guide <NUM> and a second pin hole <NUM> on a lateral side of the talus guide <NUM>. The pin holes <NUM> and <NUM> may be configured to receive pins, similar to as described above in connection with pin holes <NUM> and <NUM>. Pins extending through pin holes <NUM> and <NUM> and into the patient's talus <NUM> may help guide the saw blade, or other cutting tool, as it is inserted through the transverse cutting slot <NUM> and into the patient's talus <NUM>. In addition, the pins extending through pin holes <NUM> and <NUM> may help protect soft tissue, hard tissue, and portions of the cutting guide from being unintentionally cut or otherwise damaged.

The talus guide <NUM> may include a protrusion in the form of a tongue or paddle <NUM> extending posteriorly from an area of the talus guide <NUM> between the upper portion <NUM> and lower portion <NUM> and superior to the transverse slot <NUM>. The paddle <NUM> may be configured for insertion between the resected surface of the distal tibia <NUM> and the unresected proximal surface of the talus <NUM>. Paddle <NUM> is preferably sized and shaped to provide additional surface area contact between talus guide <NUM> and the tibia <NUM> and talus <NUM>, which may better support the foot after the tibia <NUM> has been cut. This support may be particularly useful during the step of resecting the talus <NUM> with a blade or other cutting tool through transverse slot <NUM>. All or some parts of paddle <NUM> may be patient specific in order to match corresponding surfaces of the bone, although in some embodiments the paddle <NUM> need not have any patient specific features. For example, a posterior portion of the inferior side of paddle <NUM> may have a surface contour that matches the contours of the anterior/superior surfaces of the talus dome, which may be best seen in <FIG>. In addition, paddle <NUM> may include an angled pin hole <NUM> (best shown in <FIG>) to guide the datum pin into place so the surgeon can attach the existing datum pin cutting guides. Paddle <NUM> may also help serve as a joint space evaluator to help ensure enough bone was removed from the patient so that the implants will fit on the prepared bone surface, with the height of the paddle <NUM> being based on the patient's anatomy and the amount of bone to be resected. It should be understood that, in some embodiments, the paddle <NUM> may be configured to provide relatively little contact with the bone, and an additional stabilizer (such as stabilizer <NUM> described in greater detail below) may provide most of the desired or necessary contact area (which contact may be patient specific) between the talus guide <NUM> and the patient's bone.

Talus guide <NUM> may include an additional stabilizer <NUM>, which is best shown in the view of <FIG>, which illustrates stabilizer <NUM> as a separate component. It should be understood that talus guide <NUM> is preferably a single unitary piece, and is shown as separate pieces in <FIG> purely for better illustrating certain features of the components, although the stabilizer <NUM> may optionally be fabricated separately from the rest of the talus guide <NUM> and the components may then be coupled together. Stabilizer <NUM> may include a medial wing <NUM> and a lateral wing <NUM> adapted to contact the medial and lateral aspects of the dome of the talus <NUM>. Medial and lateral wings <NUM>, <NUM> may each extend away from a center portion of stabilizer <NUM> and curve posteriorly, with the surfaces preferably including contours that match the contours of the patient's talus <NUM> to help provide better stabilization of the talus guide <NUM> on the talus, as best shown in <FIG>. In addition to medial and lateral wings <NUM>, <NUM>, stabilizer <NUM> may include two posterior rails <NUM>, as best shown in <FIG>. Posterior rails <NUM> may both be relatively thin members protruding from an inferior surface of stabilizer <NUM> and running in an anterior to posterior direction. Some portions of rails <NUM>, including the inferior surfaces, may be contoured to the patient's bone, and in particular to the corresponding contours of the superior aspect of the neck of the talus <NUM>. The contact between rails <NUM> and the superior aspect of the neck of the talus <NUM> may further help stabilize talus guide <NUM> in place, as best shown in <FIG>. In all embodiments of talus guides described herein with a stabilizer <NUM> or similar stabilizer structure, it should be understood that the paddle <NUM> (or similar structure) may be omitted from the talus guide.

As noted above, pin holes <NUM> and <NUM> of talus guide <NUM> may be slid over pins protruding from the tibia <NUM> that were previously engaged with the tibia guide <NUM>. Prior to resecting the talus <NUM>, the patient's foot may be rotated so that the talus <NUM> is in proper contact with the paddle <NUM> and stabilizer <NUM> of talus guide <NUM>. Once the talus <NUM> is in the proper position, the surgeon may insert pins through pin holes <NUM> and <NUM> and into the properly positioned talus <NUM>. Pin holes <NUM> and <NUM> are positioned inferiorly of the transverse cutting slot <NUM>. In addition to pin holes <NUM> and <NUM> being positioned to help attach talus guide <NUM> to the talus <NUM>, the pin holes <NUM> and <NUM> may be positioned to align with the medial and lateral inferior walls of the talus implant so that, when the medial and lateral walls of the talus are prepared to receive the talus implant, there are no holes remaining from pins that were previously inserted through pin holes <NUM> and <NUM>. Other pin holes that are not illustrated in <FIG> may be provided to give a surgeon additional options for attachment, including pin holes on one or both of the medial and lateral wings <NUM>, <NUM> of the stabilizer <NUM>. It should be noted that, similar to tibia guide <NUM>, talus guide <NUM> may include one or more fixation blocks, <NUM>, <NUM>, which may assist in the fixation of the talus guide <NUM> during manufacturing operations.

Talus guide <NUM> may include a first alignment hole <NUM> and a second alignment hole <NUM>, each alignment hole adapted to receive an alignment rod therethrough. Alignment hole <NUM> may include a top opening (best shown in <FIG>) and a bottom opening (<FIG>), the alignment hole <NUM> extending substantially orthogonal to transverse cutting slot <NUM>. Similar to the tibia guide <NUM>, an alignment rod may be passed through alignment hole <NUM> to check for desired alignment of the talus guide <NUM> to the talus <NUM> and/or tibia <NUM>, as shown in <FIG>. Alignment hole <NUM>, best shown in <FIG> and <FIG>, may extend in an anterior-to-posterior direction substantially parallel to the anterior-to-posterior passage within slot <NUM> and may be aligned with the anterior-to-posterior vector of the angled pin hole <NUM>. As shown in <FIG>, an alignment rod may be positioned within alignment hole <NUM> to check the suitability of the alignment of the patient's forefoot.

Tibia guides and talus guides, including those described herein, may be provided to the surgeon or other personnel with physical model bones to assist the surgeon. For example, an accurate three-dimensional physical model of the patient's distal tibia <NUM>' is shown in <FIG>, and may be provided along with a patient specific tibia guide such as tibia guide <NUM>. Similarly, an accurate three-dimensional physical model of the patient's talus <NUM>' may be provided along with a patient specific talus guide such as talus guide <NUM>. These physical models <NUM>' and <NUM>' may be used preoperatively by the surgeon to help explain the surgery to the patients and also to help with additional case planning as may be necessary. The physical models <NUM>' and <NUM>' may also be used intraoperatively as a basis for comparing the fit of the relevant guides <NUM> and <NUM> to the patient's native bone.

<FIG> illustrates a wing accessory <NUM> that may be used with tibia guide <NUM>, or any other tibia guide described herein. Wing accessory <NUM> may include a first portion adapted for insertion into the transverse cutting guide slot <NUM> when the tibia guide <NUM> is coupled to the tibia, but prior to making the transverse resection. It should be understood that the portion of the wing accessory <NUM> inserted into transverse slot <NUM> is not visible in <FIG>. Wing accessory <NUM> may also include a main body <NUM> that is coplanar to the transverse cutting slot <NUM> when the wing accessory <NUM> is inserted in the cutting slot <NUM>. Wing accessory <NUM> may further include an extension member <NUM> extending from the main body <NUM>, the extension member <NUM> also being coplanar with the transverse cutting slot <NUM> when the wing accessory <NUM> is coupled to tibia guide <NUM>. As shown in <FIG>, the extension member <NUM> may be adapted to extend in an anterior to posterior direction adjacent the distal tibia <NUM> when the wing accessory <NUM> is coupled to tibia guide <NUM>. Prior to resecting the tibia <NUM>, the wing accessory <NUM> may be coupled to tibia guide <NUM> and an X-ray or other suitable imaging technique may be used to image the extension member <NUM> relative to the tibia <NUM>, for example using a lateral X-ray as shown in <FIG>. The extension portion <NUM> may readily show the surgeon where the resection in the tibia <NUM> will be located if the transverse cutting slot <NUM> is used, helping the surgeon confirm proper placement. The extension member <NUM> may include a plurality of pins or other protrusions that may be used to indicate distances. For example, each pin or protrusion may be spaced an equal distance from an adjacent pin or protrusion, for example about <NUM> from the center of one pin to the center of the next pin. In addition, each pin may extend an equal distance above and below the extension member <NUM>, for example about <NUM> above and about <NUM> below the extension member <NUM>. Such features may assist the surgeon in determining or confirming relevant distances, such as desired cut distances. It should be understood that the wing accessory may be similarly used with the talus guide <NUM> to determine or confirm relevant cut distances and alignment of the talus guide <NUM> relative to the talus <NUM>. Wing accessory <NUM> may include a hole or other aperture that may assist a user in grasping the wing accessory <NUM>, for example by pulling the wing accessory <NUM> to remove the wing accessory from the cutting guide slot <NUM>.

<FIG> shows an alternative construction of a transverse cutting slot <NUM>' that may be used in place of transverse cutting slot <NUM> of tibia guide <NUM>, or in place of any other transverse cutting slot of any tibia or talus guide described herein. Compared to transverse cutting slot <NUM>, which is substantially planar and bounded by parallel straight walls, transverse cutting slot <NUM>' may be defined by top and bottom walls that are "wavy," where the top wall includes peaks that align with troughs of the bottom wall, and the bottom wall includes peaks that align with troughs of the top wall. With this configuration, as shown in <FIG>, a saw blade or other cutting tool may still be guided to make a substantially planar cut, but the saw blade may only contact the peaks of the top and bottom walls that define the transverse cutting slot <NUM>'. Compared to cutting slot <NUM>, a saw blade through cutting slot <NUM>' may have fewer areas of contact with surfaces of the cutting guide, which may lead to less cutting or damaging of both the saw blade and the walls that define the cutting slot <NUM>'. <FIG> shows a further alternative construction of a transverse cutting slot <NUM>", which may be used in place of any transverse cutting slots described herein. As shown in <FIG>, the structure forming the transverse cutting slot <NUM>'' may include a first pair of anterior and posterior bump-outs or extensions that extend inferiorly from the superior surface of the cutting slot in a medial-to-lateral direction, and a second pair of anterior and posterior bump-outs or extensions that extend superiorly from the inferior surface of the cutting slot in a medial-to-lateral direction. The two anterior bump-outs may be positioned adjacent one another, and the two posterior bump-outs may be positioned adjacent one another, to provide the main points of contact between the saw blade and the structure forming the cutting slot <NUM>". With this configuration, there is little or no contact between the saw blade and the structure that defines the cutting slot <NUM>'' between the anterior and posterior bump-outs, helping to reduce the overall area of contact between the saw blade and the cutting guide. The geometry of the transverse cutting slot <NUM>" shown in <FIG> may be beneficial from a manufacturing standpoint, as it may be simpler to create compared to more complex shapes that achieve a similar goal. It should also be understood that similar bump-outs to those illustrated for the cutting slot in <FIG> may be utilized in any of the apertures described herein that function to receive pins through the apertures.

<FIG> illustrate another embodiment of a patient-specific tibia guide <NUM> that is similar to tibia guide <NUM> in most respects. Tibia guide <NUM> may have various features similar to other tibia guides described herein, including tibia guides <NUM> and <NUM>. For example, tibia guide <NUM> includes an anterior surface <NUM> and a posterior bone-contacting surface <NUM> opposite the anterior surface <NUM>. Tibia guide <NUM> is configured to attach to the anterior surface of the patient's tibia <NUM>. The posterior bone-contacting surface <NUM> may be keyed to the geometry of the patient's tibia <NUM> so that tibia guide <NUM> may fit onto the patient's tibia <NUM> in only one (or substantially only one) position and orientation. In addition, the posterior bone-contacting surface <NUM> may be curved posteriorly from the center toward the medial and lateral edges so that the tibia guide <NUM> at least partially wraps around the tibia <NUM> to increase surface area contact between the tibia guide <NUM> and the tibia <NUM> in the medial-to-lateral direction. Still further, the posterior bone-contacting surface <NUM> may be curved posteriorly from the center toward the superior and inferior edges so that the tibia guide <NUM> at least partially wraps around the tibia <NUM> to increase surface area contact between the tibia guide <NUM> and the tibia <NUM> in the superior-to-inferior direction. As in other embodiments described herein, posterior bone-contacting surface <NUM> may include a portion that extends medial of and inferior to the transverse cutting guide for placement on the patient's medial malleolus which may further help stabilize the guide.

Two pin holes <NUM> and <NUM> extend through both the anterior surface <NUM> and posterior surface <NUM> of the tibia guide <NUM> and are sized and shaped to receive fixation pins, or other suitable fixation means, therethrough to fix the tibia guide <NUM> to the patient's tibia <NUM>. In the illustrated example, pin holes <NUM> and <NUM> are positioned superior to a transverse cutting guide slot <NUM> of the tibia guide <NUM>. Pin hole <NUM> may be positioned on a medial side of the tibia guide <NUM> and pin hole <NUM> may be positioned on a lateral side of the tibia guide <NUM>, with pin holes <NUM> and <NUM> being positioned substantially the same height from cutting guide slot <NUM>. In the illustrated embodiment, pin holes <NUM> and <NUM> are positioned just superior of cutting guide slot <NUM>. Pin holes <NUM> and <NUM> may be formed in cylindrical or other shaped projections, in order to provide greater surface area for contact between pins inserted through pin holes <NUM> and <NUM> and tibia guide <NUM>. Pin holes <NUM> and <NUM> may have positions and orientations that correspond to pin hole positions and orientations of a talus guide <NUM> so that the talus guide <NUM> may be slid over the same pins used to hold the tibia guide <NUM> to the patient's tibia <NUM>. Further, pin holes <NUM> and <NUM> may have positions and orientations that correspond to holes in the tibia implant so that, when the holes are drilled out of the tibia <NUM> for implantation of the tibia implant, no holes remain in the bone from use of the tibia guide <NUM> or the talus guide <NUM>.

Tibia guide <NUM> may include two additional pin holes <NUM> and <NUM>. Pin hole <NUM> may be positioned on a medial side of the guide and pin hole <NUM> may be positioned on a lateral side of the guide, with both pin holes <NUM> and <NUM> being positioned near a superior or top end of the guide. Pin holes <NUM> and <NUM> may be defined within cylindrical projections similar to pin holes <NUM> and <NUM>. Pin holes <NUM> and <NUM> may be referred to as contingency or "bailout" holes with pin holes <NUM> and <NUM> only intended for use with a universal cutting guide instead of the patient-specific tibia guide <NUM> and talus guide <NUM>. In other words, if a surgeon decides that the tibia guide <NUM> should not be used for any reason, pins may be passed through pin holes <NUM> and <NUM> into the tibia <NUM>, the tibia guide <NUM> may be removed by sliding the guide off the pins, and a traditional universal (i.e. non-patient specific) guide with holes corresponding to the position of pin holes <NUM> and <NUM> may be used to complete the procedure.

The tibia guide <NUM> may also include one or more visualization windows <NUM>. Windows <NUM> may facilitate the surgeon in better visualizing the patient's tibia <NUM> and checking proper fitting between the tibia guide <NUM> and the patient's tibia <NUM>. In the illustrated embodiment, windows <NUM> may be in the form of a plurality of cut-outs or other apertures in the portion of tibia guide <NUM> contoured to the patient's bone contours, and the cut-outs may extend from the anterior surface <NUM> to the posterior surface <NUM>. In the illustrated embodiment, may of the windows <NUM> are honey-comb shaped or hexagonal. As illustrated, windows <NUM> include a first group of windows on a lateral side of the tibia guide <NUM> and a second group of windows on the medial side of the tibia guide. The windows <NUM> may include a plurality of hexagonal shaped cut-outs, as well as other shaped cut-outs, such as substantially diamond-shaped cutouts on a superior surface of the tibial cutting guide <NUM>. However, it should be understood that other shapes or other groups of shapes may be suitable. In particular, any shaped cut-outs that provide for good visibility while leaving enough structure to maintain structural integrity and rigidity of the tibia guide <NUM> may be suitable in place of the specific embodiment shown. Further, these diamond-shaped cutouts or lattice structure may be used, where appropriate, as pin holes to receive pins therethrough.

A cutting guide <NUM> may include a first guide portion <NUM> and a second guide portion <NUM>, which may be substantially similar to the cutting guide slot <NUM> of <FIG> and cutting guide slot <NUM> of <FIG>. The first guide portion <NUM> may generally consist of two parallel transverse walls defining a first slot therebetween. This first guide portion <NUM> and corresponding first slot are configured to assist the surgeon in creating a flat transverse cut in the patient's tibia <NUM>. Preferably, the slot of the first guide portion <NUM> is substantially planar and, when tibia guide <NUM> is coupled to the tibia <NUM>, the plane of the slot <NUM> is substantially orthogonal to the mechanical axis of the tibia <NUM>. The second guide portion <NUM> may consist of a single wall extending at an oblique angle to the first slot <NUM>, which may in particular be an obtuse angle. However, in some circumstances it may be suitable for the second guide portion <NUM> to extend perpendicularly relative to the first slot. The second guide portion <NUM> may define a second slot, although in this instance the second slot is generally open because it is bounded on only one side. This second slot may be configured to assist the surgeon in releasing the resected bone from the medial malleolus and/or from the medial side of the tibia, superior to the medial malleolus. The configuration of the first slot being defined by a fully (or nearly fully) enclosed first guide portion <NUM> may facilitate a saw blade or other resection tool being directed in a limited intended manner. The configuration of the second slot being open and bounded only by the second guide portion <NUM> may provide additional freedom of movement that may be necessary for the surgeon to make the cut. Although the first cutting guide portion <NUM> is shown as a slot that is substantially closed, the cutting guide portion may take other forms described above in connection with other embodiments of tibia guides.

Tibia guide <NUM> may include an alignment hole <NUM> adapted to receive an alignment rod therethrough. Alignment hole <NUM> may extend from the superior end of tibia guide <NUM> and to or through first guide portion <NUM>, and is preferably orthogonal to the transverse cutting slot defined by the first guide portion <NUM>. With this configuration, an alignment rod may be passed through alignment hole <NUM> to check for desired alignment of the tibia guide <NUM> to the tibia <NUM>, similar to the embodiment shown in <FIG>. Tibia guide <NUM> may also include one or more fixation blocks, <NUM>, <NUM>, which may be assist in fixation of the tibia guide <NUM> during manufacturing operations. For example, fixation blocks <NUM>, <NUM> may be used to guide a milling machine that creates certain features in the tibia guide <NUM>. In one example, tibia guide <NUM> is additively manufactured, with certain features being milled into the tibia guide <NUM>, and the fixation blocks <NUM>, <NUM> may assist in guiding the milling process.

The main components of tibia guide <NUM> described above are substantially similar to those of tibia guide <NUM> already described. One main difference of tibia guide <NUM> is the inclusion of a rotational alignment sight. In the illustrated embodiment, the rotational alignment sight includes a projection <NUM> extending superiorly from a medial side of the tibia guide <NUM> near pin hole <NUM>. Projection <NUM> may take any suitable shape, including a thin member in the medial-to-lateral direction having a generally triangular shape that narrows in the inferior-to-superior direction. The rotational alignment sight may also include an alignment window <NUM>, which may be define a general "U"-shape profile. As best illustrated in <FIG>, the patient's tibia may be rotated to achieve perfect medial gutter perspective, which may be confirmed by the rotational alignment sight. In particular, <FIG> illustrates a rotational configuration in which the projection is not aligned with the alignment window <NUM>, while <FIG> illustrates a rotational configuration in which the projection is aligned with the alignment window <NUM>. However, it should be understood that other shapes and configurations of the projection <NUM> and alignment window <NUM> may provide similar functionality. For example, a spherical or circular bead and a circular hole may be implemented so that, upon lining up correctly, the spherical or circular bead forms a complete circle with the circular hole. In other embodiments, a single pillar may be provided in a first plane, with a pair of pillars provided in a second plane so that, upon achieving the desired alignment, the single pillar is substantially equidistant between the pair of pillars. Other complementary shapes that provide a visual indication of proper alignment when viewed in a particular orientation with respect to one another may also be suitable for use in this feature.

<FIG> illustrate another embodiment of a patient-specific talus guide <NUM> that is similar to talus guide <NUM> in most respects. Talus guide <NUM> may have various features similar to other talus guides described herein, including talus guides <NUM> and <NUM>. For example, talus guide <NUM> may include an anterior surface <NUM> and one or more posterior bone-contacting surfaces <NUM> described in greater detail below. Talus guide <NUM> may include an upper portion configured to attach to the anterior surface of the patient's tibia <NUM> and a lower portion configured to attach to the anterior surface of the patient's talus <NUM>. The posterior bone-contacting surfaces <NUM> of the upper portion and lower portion may be keyed to the geometry of the patient's tibia <NUM> and talus <NUM>, respectively, so that talus guide <NUM> may fit onto the patient's tibia <NUM> and talus <NUM> in only (or substantially only) a single position and orientation, as described in greater detail below. As with other talus guides described herein, talus guide <NUM> may be coupled to the talus <NUM> only, or to both the tibia <NUM> and the talus <NUM>, with any of the contact areas optionally being patient-specific and configured to fit in only one or substantially only one orientation.

Two pin holes <NUM> and <NUM> may extend through both the anterior surface <NUM> and a posterior surface <NUM> of the upper portion of the talus guide <NUM> and are sized and shaped to receive fixation pins, or other suitable fixation means, therethrough to fix the upper portion of the talus guide <NUM> to the patient's tibia <NUM>. In the illustrated example, pin holes <NUM> and <NUM> are positioned superior to a transverse cutting guide slot <NUM> of the talus guide <NUM>. Pin hole <NUM> and may be positioned on a medial side of the talus guide <NUM> and pin hole <NUM> may be positioned on a lateral side of the talus guide <NUM>, with pin holes <NUM> and <NUM> being positioned substantially the same height from transverse slot <NUM>. Pin holes <NUM> and <NUM> may be defined by cylindrical or other shaped projections, in order to provide greater surface area for contact between a pin inserted through pin holes <NUM> and <NUM>. Pin holes <NUM> and <NUM> may have the same size, position, and orientation with respect to one another as pin holes <NUM> and <NUM> of tibia guide <NUM> so that, after use and removal of the tibia guide <NUM>, the pin holes <NUM> and <NUM> of the talus guide <NUM> may be slipped over the pins that were previously used with pin holes <NUM> and <NUM> of the tibia guide <NUM>.

The talus guide <NUM> may include a protrusion in the form of a tongue or paddle <NUM> extending posteriorly from an area of the talus guide <NUM> between the upper portion and lower portion and superior to the transverse slot <NUM>. The paddle <NUM> may be configured for insertion between the resected surface of the distal tibia <NUM> and the unresected proximal surface of the talus <NUM>. Paddle <NUM> is preferably sized and shaped to provide additional surface area contact between talus guide <NUM> and the tibia <NUM> and talus <NUM>, which may better support the foot after the tibia <NUM> has been cut. This support may be particularly useful during the step of resecting the talus <NUM> with a blade or other cutting tool through transverse slot <NUM>. All or some parts of paddle <NUM> may be patient specific in order to match corresponding surfaces of the bone, although in some embodiments the paddle <NUM> need not have any patient specific features. For example, a posterior portion of the inferior side of paddle <NUM> may have a surface contour that matches the contours of the anterior/superior surfaces of the talus dome, similar to the embodiment shown in <FIG>. In addition, paddle <NUM> may include an angled pin hole <NUM> to guide the datum pin into place so the surgeon can attach the existing datum pin cutting guides. Paddle <NUM> may also help serve as a joint space evaluator to help ensure enough bone was removed from the patient so that the implants will fit on the prepared bone surface, with the height of the paddle <NUM> being based on the patient's anatomy and the amount of bone to be resected. It should be understood that, in some embodiments, the paddle <NUM> may be configured to provide relatively little contact with the bone, and an additional stabilizer (such as a stabilizer including wings <NUM>, <NUM> described in greater detail below) may provide most of the desired or necessary contact area (which contact may be patient specific) between the talus guide <NUM> and the patient's bone. It should be understood that, even while paddle <NUM> is larger in talus guide <NUM> compared to the paddle <NUM>' in talus guide <NUM>', the wings of the stabilizer may provide the primary contact area between the talus guide and the patient's talus in both embodiments.

Talus guide <NUM> may include an additional stabilizer, which is best shown in <FIG>. The additional stabilizer may include a medial wing <NUM> and a lateral wing <NUM> adapted to contact the medial and lateral aspects of the dome of the talus <NUM>. Medial and lateral wings <NUM>, <NUM> may each extend away from a center portion of the stabilizer and curve posteriorly, with the surfaces preferably including contours that match the contours of the patient's talus <NUM> to help provide better stabilization of the talus guide <NUM> on the talus. Although not shown in connection with <FIG>, the stabilizer may include two posterior rails, similar to posterior rails <NUM> of talus guide <NUM> shown in <FIG>.

As noted above, pin holes <NUM> and <NUM> of talus guide <NUM> may be slid over pins protruding from the tibia <NUM> that were previously engaged with the tibia guide <NUM>. Prior to resecting the talus <NUM>, the patient's foot may be rotated so that the talus <NUM> is in proper contact with the paddle <NUM> and the stabilizer of talus guide <NUM>. Once the talus <NUM> is in the proper position, the surgeon may insert pins through pin holes <NUM> and <NUM> and into the properly positioned talus <NUM>. Pin holes <NUM> and <NUM> are positioned inferiorly of the transverse cutting slot <NUM>. It should be noted that, similar to tibia guide <NUM>, talus guide <NUM> may include one or more fixation blocks, <NUM>, <NUM>, which may assist in the fixation of the talus guide <NUM> during manufacturing operations. For example, fixation blocks <NUM>, <NUM> may be used to guide a milling machine that creates certain features in the talus guide <NUM>. In one example, talus guide <NUM> is additively manufactured, with certain features being milled into the talus guide <NUM>, and the fixation blocks <NUM>, <NUM> may assist in guiding the milling process.

Talus guide <NUM> may include a first alignment hole <NUM> and a second alignment hole <NUM>, each alignment hole adapted to receive an alignment rod therethrough. Alignment hole <NUM> may include a top opening and a bottom opening, the alignment hole <NUM> extending substantially orthogonal to transverse cutting slot <NUM>. Similar to the tibia guide <NUM>, an alignment rod may be passed through alignment hole <NUM> to check for desired alignment of the talus guide <NUM> to the talus <NUM> and/or tibia <NUM>, similar to the embodiment shown in <FIG>. Alignment hole <NUM> may extend in an anterior-to-posterior direction substantially parallel to the anterior-to-posterior passage within slot <NUM> and may be aligned with the anterior-to-posterior vector of the angled pin hole <NUM>. Similar to the embodiment shown in <FIG>, an alignment rod may be positioned within alignment hole <NUM> to check the suitability of the alignment of the patient's forefoot.

Although most of the features of talus guide <NUM> described above are similar to corresponding features of talus guide <NUM>, talus guide <NUM> has additional features. For example, as best seen in <FIG> and <FIG>, tongue or paddle <NUM> may include one, two, or more cutouts 1275a or other indicia. In the illustrated embodiment, paddle <NUM> includes two cutouts 1275a which are positioned along an axis that corresponds to the channel that extends along angled pin hole <NUM>. In other words, when the datum pin is passed through the angled pin hole <NUM>, the axis of the datum pin aligns with the cutouts 1275a. Thus, the cutouts 1275a may provide an indication to the user of the trajectory that the datum pin will have, prior to actually being inserted into angled pin hole <NUM>. In other embodiments, the cutouts 1275a may take the form of indicia such as markings or lines on the paddle <NUM>.

Referring to <FIG> and <FIG>, talus guide <NUM> may include an auxiliary pin hole <NUM>. Auxiliary pin hole <NUM> is shown as positioned inferior to cutting guide slot <NUM> and between pin holes <NUM> and <NUM>, closer to pin hole <NUM>. Pin hole <NUM> may be generally similar in structure and function to pin holes <NUM> and <NUM>, providing an option for additional stabilization of the talus guide <NUM> by passing a fixation pin through the auxiliary pin hole <NUM> into the talus <NUM>. In other embodiments the auxiliary pin hole <NUM> may be positioned in other locations, for example closer to pin hole <NUM>, and in further embodiments multiple auxiliary pin holes may be included for additional stabilization options.

<FIG> are top and bottom perspective views, respectively, of a talus guide <NUM>' that is similar or identical to talus guide <NUM> in almost all respects, with the exception of the paddle <NUM>'. Thus, other aspects of the talus guide <NUM>' are not described again here. As is clear from the figures, paddle <NUM>' has a generally similar shape and function as paddle <NUM>, except that paddle <NUM>' has a significantly smaller width in the medial-to-lateral direction compared to paddle <NUM>. With this configuration, paddle <NUM>' may provide a relatively small amount of the overall patient-specific contact between talus guide <NUM>' and the patient's tibia <NUM> and/or talus <NUM>. Rather, the medial wing <NUM>' and lateral wing <NUM>' of the stabilizer of talus guide <NUM>', which may be substantially similar to the medial wing <NUM> and lateral wing <NUM> of talus guide <NUM>, may be the primary patient-specific contact surfaces between the talus guide <NUM>' and the patient's bone.

Claim 1:
A device (<NUM>, <NUM>, <NUM>) for assisting in performing an ankle arthroplasty on a non-resected bone surface of a tibia (<NUM>) comprising:
a posterior surface (<NUM>) having a mating surface configured to engage the non-resected bone surface of the tibia in a matching manner on account of a patient-specific nature of the mating surface, the matching manner registering a single relative position of the mating surface relative to the non-resected bone surface of the tibia, the patient specific nature of the mating surface portion having been generated in the device prior to the device being brought into contact with the bone surface of the tibia or employed in the arthroplasty;
a first guide member (<NUM>) defining a transverse cutting instrument guide slot (<NUM>) and having an anterior entrance and a posterior exit, wherein the transverse guide slot (<NUM>) is configured to guide a cutting instrument along a transverse planar guide surface that is substantially orthogonal to a tibial mechanical axis of the tibia when the non-resected tibia surface is engaged to the mating surface in the matching manner; and
a second guide member (<NUM>) coupled to the first guide member (<NUM>), the second guide member defining an angled guide surface angled obliquely to the transverse guide slot,
wherein the mating surface has a first curvature that is curved posteriorly from a central area of the mating surface toward a medial and a lateral edge of the mating surface so that the central area of the mating surface is positioned anterior to the medial and lateral edges of the mating surface, the device (<NUM>) being characterized in that, when in contact with the non-resected bone surface, the first curvature of the mating surface at least partially wraps around the non-resected bone surface in a medial-to-lateral direction.