Implants/procedures related to tibial tuberosity advancement

A tibial tuberosity advancement (TTA) system is configured to maintaining a tuberosity in an advanced position relative to a tibial body. The TTA system includes an implant, a spacer, and a spacer fixation member.

TECHNICAL FIELD

The present application generally relates to systems, apparatus, and methods for stabilizing a deficient stifle, and more particularly, to systems, apparatus, and methods for performing a tibial tuberosity advancement procedure.

BACKGROUND

Referring toFIG. 1, the knee joint20of quadrupeds, such as dogs and cats, connects the tibia22and the femur24in a pivotal relationship. The knee joint20includes a number of stabilizing tendons and ligaments that supports the joint during anatomical function. For instance, the cranial cruciate ligament (CCL), similar to the anterior cruciate ligament in humans, bears the majority of the animal's weight, and is important to the overall stability of the knee joint20. The CCL is attached to the tibia22and the femur24, and in general prevents or limits sliding of the tibia22forward or cranially relative to the femur24, and further limits internal rotation of the tibia22relative to the femur24as well as hyperextension of the knee joint20. The knee joint20further includes a meniscus26that is disposed between the tibia22and the femur24, and absorbs impact and provides a gliding surface between the femur24and tibial plateau28of the tibia22.

The tibia22includes a tibial body23and a tuberosity30that extends from the tibial body23. The patellar tendon32is anchored between the tuberosity30and the femur24. As illustrated inFIG. 1, a line27extending through the patellar tendon32that is both normal to the patellar tendon and directed toward the tibial plateau28is angularly offset with respect to a line29that lies in the plane generally defined by the tibial plateau28, and intersects the line27at a location between the patellar tendon32and the tibial plateau28. Accordingly, when the CCL is damaged, which is a common injury in canines, the patellar ligament32does not prevent the femur24from travelling along the tibial plateau28due to tibiofemoral sheer forces when weight is applied to the injured knee join20. As a result, damage to the CCL often results in lameness of the affected knee, damage to the meniscus26due to forces applied by the femur24, and degenerative joint diseases. Furthermore, the animal can tend to overcompensate for the injured knee joint20, which can result in rupture of the CCL of the other knee during a weight-bearing anatomical function.

Referring also toFIG. 2, tibial tuberosity advancement (TTA) is a procedure designed to repair a knee joint20that has been affected by a damaged cranial cruciate ligament. Conventional TTAs include the step of performing an osteotomy cut to separate the tibial tuberosity30from the tibial body23, and subsequently advancing the tibial tuberosity30, and thus also the patellar tendon32, cranially to a position spaced from the tibia22so as to define a gap40between the tibial tuberosity30and the tibial body23. For instance, during a TTA, the tibial tuberosity30and the patellar tendon32are typically advanced such that the line27extending through the patellar tendon32that is both normal to the patellar tendon32and directed toward the tibial plateau28is also substantially parallel to, and can be coincident with, the line29that lies in the plane generally defined by the tibial plateau28. Thus, the line27can be substantially parallel to or coincident with the plane defined by the tibial plateau28. In general, the line27is more parallel to, or coincident with, the line29, and thus the plane defined by the tibial plateau28, after the TTA than before the TTA. The tibial tuberosity30is then fixed in the advanced position, which neutralizes the tibiofemoral sheer force when weight is applied to the knee joint20, thereby reducing or altogether bypassing the anatomical function of the CCL.

Thus, with continuing reference toFIG. 2, a conventional TTA system34includes a bone plate36that is connected to the tibia22at one end, and to the advanced tibial tuberosity30at another end so as to provide fixation of the advanced tibial tuberosity30and the tibial body23, and a spacer38in the form of a cage that is separate from the bone plate36and is disposed and connected between the advanced tibial tuberosity30and the tibial body23so as to maintain the gap40between the tibial tuberosity30and the tibial body23against the caudally-directed force of the patellar tendon32.

A number instruments, apparatus, systems, and methods have been developed to conduct TTA procedures in dogs. However, improvements to those instruments and implants are still desired.

SUMMARY

The present disclosure relates to TTA systems for maintaining an advanced tuberosity in an advanced position relative to a tibial body. The advanced position of the tuberosity is spaced cranially and proximally with respect to a first position when the tuberosity is integral with the tibial body. In one embodiment, the TTA system generally includes an implant, a spacer, and a spacer fixation member. The implant includes an implant body that defines a proximal end portion that configured to support the advanced tuberosity in the advanced position, a distal end portion that is configured to be attached to the tibial body, and an intermediate implant portion that extends between the proximal end portion and distal end portion. The intermediate portion is shaped so as to space the proximal end cranially and proximally with respect to the distal end portion an amount, or a distance, sufficient so as to maintain the advanced tuberosity in the advanced position. The spacer is configured and sized to fit within a gap disposed between the advanced tuberosity and the tibial body23when the distal end portion and the proximal end portion are attached to the tibial body23and the advanced tuberosity, respectively. The spacer includes a spacer body, and defines a slot that extends through the spacer body. The spacer fixation member includes a first end portion configured to be attached to the advanced tuberosity, a second end portion that is configured to be attached to the tibial body, and an intermediate fixation portion extending between the first end and the second end. The intermediate fixation portion is configured and sized to be at least partially received in the slot so as to couple the spacer fixation member to the spacer.

The present disclosure further relates to TTA advancement assemblies that are configured to advance a tuberosity from a first position to an advanced position relative to a tibial body after an osteotomy has been made between the tuberosity and the tibial body. In an embodiment, the TTA advancement assembly includes an advancement body that is configured to be coupled to the tibial body, and a distraction arm movably coupled to the advancement body. The distraction arm is configured to be coupled to the tuberosity, and is configured to translate to move along with the tuberosity relative to the tibial body, such that the distraction arm moves a predetermined distance relative to the advancement body. The translation of the distraction arm over the predetermined distance causes the advancement assembly to provide an indication that the tuberosity has advanced from the first position to the advanced position.

In an embodiment, the TTA advancement assembly includes an advancement body that is configured to be coupled to the tibial body; and an angular adjustment member pivotally coupled to the advancement body. The angular adjustment member is configured to pivot relative to the advancement body about a pivot axis, and includes a contact member that is configured to fit in a gap defined by the osteotomy. The angular adjustment member is configured to be pivotally fixed relative to the advancement body such that the advancement body is oriented at a predetermined advancement angle relative to the osteotomy when the contact member is disposed in the osteotomy.

The present disclosure further relates to TTA methods for advancing a tuberosity from a first position to an advanced position relative to a tibial body after an osteotomy has been made between the tuberosity and the tibial body. In an embodiment, the TTA method includes one or more of the following steps: a) coupling an advancement body to the tuberosity via a distraction arm that is movably coupled to the advancement body, the distraction arm configured to translate relative to the advancement body; b) placing a contact member that is coupled to the advancement body in a gap formed during the osteotomy, the gap disposed between the tuberosity and the tibial body; c) moving the distraction arm relative to the advancement body to move the tuberosity between the first position and the advanced position.

DETAILED DESCRIPTION OF THE DRAWINGS

Certain terminology is used in the following description for convenience only and is not limiting. The words “right”, “left”, “lower” and “upper” designate directions in the drawings to which reference is made. The words “medially” and “laterally” refer to directions toward and away from, respectively, a midline extending through a body, for example from a head to a tail of a canine body. The words “proximal” and “distal” refer to directions toward or away from where an appendage is joined to the rest of the body. The words “anterior”, “posterior”, “dorsal”, “ventral” and related words and/or phrases designate preferred positions and orientations in the canine body to which reference is made and are not meant to be limiting. For example “anterior” and “posterior” refer to positions closer to the head and tail, respectively. While “dorsal” and “ventral” refer to positions closer to the spinal column and the belly, respectively. The terminology includes the above-listed words, derivatives thereof and words of similar import. For example, as shown inFIG. 8A, the arrow60may represent the proximal, dorsal, or upward direction. The arrow62may represent the distal, ventral, or downward direction. The arrow64may represent the front, cranial or anterior direction. The arrow66may represent the caudal, rear or posterior direction. The arrow68may represent the lateral or away direction. The arrow70may represent the medial or toward direction.

With reference toFIG. 3, a Tibial Tuberosity Advancement (TTA) system100can be configured to stabilize cranial cruciate ligament-deficient stifles in quadrupeds. In one embodiment, the TTA system100includes an implant104, such as a tibial tuberosity advancement (TTA) implant, for a quadruped. The implant104can be constructed as a bone fixation member106, such as a bone plate108. In the depicted embodiment, the implant104includes an implant body110that includes a proximal end portion112, an opposed distal end portion114, and an intermediate implant portion116disposed between the proximal end portion112and the distal end portion114.

The proximal end portion112of the implant body110can be configured to be attached to the tuberosity30that has been advanced along with the patellar tendon32(shown inFIG. 1) in a direction cranially relative to the tibial body23from a first position to an advanced position. The distal end portion114of the implant body110can be configured to be attached to the tibial body23. It should be appreciated that the patellar tendon32is attached to the tuberosity30at an anatomical attachment location43, and that the tuberosity30can be resected, and thus separated, from the tibial body23at a location caudal of the attachment location43such that the patellar tendon32, including the attachment location43, is advanced along with the separated tuberosity30from the first position to the advanced position. The proximal end portion112, the distal end portion114, and the intermediate implant portion116can collectively be a monolithic structure. Alternatively, proximal end portion112, the distal end portion114, and the intermediate implant portion116can be discrete components that are connected to each other to form the implant body110.

The proximal end portion112can be contoured and configured to conform to a medial surface or lateral surface of the tuberosity30to facilitate attachment of the implant104to the tuberosity30. Moreover, the proximal end portion112includes one or more attachment locations such as fastener holes. In the depicted embodiment, the proximal end portion112of the implant body110includes four fastener holes118a,118b,118c, and118d. However, the proximal end portion112may include more or fewer fastener holes. Irrespective of the specific number of fastener holes, each fastener hole118a,118b,118c, and118dextends through the implant body110, and is configured and sized to receive a fastener120, such as a bone anchor, that is capable of attaching the implant104to the tuberosity30.

Examples of suitable fasteners120include, but are not limited to, bone screws, nails, pins, and any other apparatus that is configured to attach the implant104to the tuberosity30. For instance, the fastener holes118a,118b,118c, and118dcan be threaded holes that are configured to receive a bone screw. Furthermore, the fasteners holes118a,118b,118c, and118dcan be conical thread holes that are configured receive bone screws with a threaded conical head. The insertion of fasteners120through fastener holes118a,118b,118c, and118dcauses the proximal end portion112to be attached to the tuberosity30. The fastener holes118a,118b,118c, and118dmay be spaced apart from one another and substantially aligned along a first longitudinal axis L1that extends substantially parallel to the direction of elongation of the tuberosity30when the implant104is attached to the advanced tuberosity30. In one embodiment the proximal end portion112can be elongate along the longitudinal axis L1.

The distal end portion114can be contoured and configured to conform to a medial surface or a lateral surface of the tibial body23to facilitate attachment of the implant104to the tibial body23. Further, the distal end portion114of the implant body110can include one or more anchor locations such as fastener holes. In the depicted embodiment, the distal end portion114includes a first fastener hole122aand a second fastener hole122b. Each of the fastener holes122aand122bcan be configured and sized to receive a fastener124, such as a bone anchor, capable of attaching the implant104to the tibial body23.

Examples of suitable fasteners124include, but are not limited to, bone screws, nails, pins, and any other apparatus that is configured to attach the implant104to the tibial body23. The insertion of fasteners124through the fastener holes122aand122bcauses the distal end portion114to be attached to the tibial body23. The fastener holes122aand122bmay be spaced apart from one another and substantially aligned along a second longitudinal axis L2. In one embodiment the distal end portion114can be elongate along the second longitudinal axis L2. The second longitudinal axis L2may be angularly offset from the first longitudinal axis L1.

The intermediate implant portion116of the implant body110can be elongated along the second longitudinal axis L2. Alternatively, the intermediate implant portion116may be elongated along an axis that is angularly offset from the second longitudinal axis L2. Although the drawings do not show attachment locations, such as fastener holes, in the intermediate implant portion116, it is envisioned that the intermediate implant portion116may include one or more fastener holes or any other suitable attachment feature. The intermediate implant portion116extends between the proximal end portion112and the distal end portion114and is shaped so as to space the proximal end portion112cranially with respect to the distal end portion114an amount, or a distance, sufficient so as to maintain the tuberosity30in the advanced position.

The TTA system100can further include a spacer102configured to maintain a distance between the tibial body23and the tuberosity30when the tuberosity23is in the advanced position. The spacer102can be configured and sized to at least partially fit in the osteotomy gap40defined between the tibial body23and the advanced tuberosity30. In the depicted embodiment, the spacer102can be configured as a cage126as described in detail below.

Aside from the spacer102, the TTA system100can include a spacer fixation member128that is configured to couple the spacer102to the tibial body23and the advanced tuberosity30, thereby fixing the spacer102in the osteotomy gap40. As discussed in detail below, the spacer fixation member128can be configured as a bone plate130. At least a portion of the bone plate130can be configured and sized to be inserted through the spacer102. The spacer fixation member128includes a body134, which is also referred to as a plate body. The body134of the spacer fixation member128can be elongated, and can define first end portion138, a second end portion140, and an intermediate fixation portion142(shown inFIG. 5A) disposed between the first end portion138and the second end portion140.

The first end portion138can be configured to be attached to the advanced tuberosity30. To this end, the first end portion138can be contoured and configured to conform to a lateral surface or a medial surface of the advanced tuberosity30, and can include one or more attachment locations such as fastener holes132. The fastener holes132can be configured and sized to receive a fastener136, such as a bone anchor, capable of attaching the spacer fixation member128to the advanced tuberosity30. Suitable fasteners136include, but are not limited to, bone screws, nails, pins, or any other fastener136that can attach the first end portion138to the advanced tuberosity30.

The second end portion140of the body134is configured to be attached to the tibial body23. To this end, the second end portion140can be contoured and configured to conform to a lateral surface or a medial surface of the tibial body23, and can include one or more attachment locations such as fastener holes144. In the depicted embodiment, the second end portion140includes only one fastener hole144; however, it is envisioned that the second end portion140can define more than one fastener hole144. The fastener hole144can be configured and sized to receive a fastener136, such as bone anchors. Examples of fasteners136include, but are not limited to, bone screws, nails, pins or any other apparatus that can attach the second end portion140to the tibial body23.

The intermediate fixation portion142is configured to be inserted through an opening, such as a slot, of the spacer102in order to secure the spacer102in the osteotomy gap40when the first end portion138is attached to the advanced tuberosity30and the second end is attached to the tibial body23. In the depicted embodiment, the intermediate fixation portion142can have a substantially planar configuration as described in detail below. The first end portion138, the second end portion140, and the intermediate fixation portion142can be a monolithic structure. Alternatively, the first end portion138, the second end portion140, and the intermediate fixation portion142can be discrete components connected to one another. The intermediate fixation portion142can define a substantially planar configuration that is configured to fit within a slot of the spacer102as discussed below.

With reference toFIGS. 4A-4E, the spacer102can include a spacer body148configured and sized to fit in the osteotomy gap40. The spacer body148can be elongate along a longitudinal direction150, and can define a first longitudinal end152and a second longitudinal end154that is spaced from the first longitudinal end152along the longitudinal direction150. Furthermore, the spacer body148defines a first lateral end156and a second lateral end158that is spaced from the first lateral end156along a lateral direction160. The lateral direction160is substantially perpendicular to the longitudinal direction150.

Specifically, the spacer body148may have a first transverse end164and a second transverse end166that is spaced from the first transverse end164along the transverse direction162. The transverse direction162is substantially perpendicular to the longitudinal direction150and the lateral direction160. In the depicted embodiment, the spacer body148can define a substantially partial wedge shape such that its width increases in the transverse direction162. The width of the spacer body148is defined between the first lateral end156and the second lateral end158. In the depicted embodiment, the spacer body148can define a first width W1at the first transverse end164that is greater than a second width W2at the second transverse end166. The wedge-shape of the spacer body148facilitates insertion and positioning of the spacer102in the osteotomy gap40since the osteotomy gap40has a substantially wedge shape.

The spacer102can further include an opening168that extends through spacer body148from the first longitudinal end152to the second longitudinal end154. Thus, the opening168can be elongate along the longitudinal direction150. The opening168can be constructed as a hole, and is configured to receive bone graft or any other natural or synthetic material capable of promoting bone growth. However, the opening168does not necessarily have to be filled with a bone graft or any other bone growth agent. The opening168provides an open space to permit natural bone growth when the spacer102is disposed in the osteotomy gap40. During natural bone growth, the natural bone can grow and fill at least a portion of the opening168when the spacer102is disposed in the osteotomy gap40.

The spacer102further defines a first slot170that extend through the spacer body148from the first lateral end156to the second lateral end158. Hence, the first slot170can be elongate along the lateral direction160. The first slot170is located closer to the first longitudinal end152than to the second longitudinal end154, and is configured and sized to receive at least a portion of the spacer fixation member128so as to couple the spacer102to the spacer fixation member128. In the depicted embodiment, the first slot170can define a plane that is substantially normal to the longitudinal direction150. The intermediate fixation member142can have a substantially planar configuration so that it is configured to fit within the slot170of the spacer102, thereby coupling the spacer102to the spacer fixation member128.

In addition to the first slot170, the spacer102includes at least one second slot172that extends through the spacer body148from the first lateral end156to the second lateral end158. In the depicted embodiment, the spacer102defines a plurality of second slots172that are spaced from each other along the longitudinal direction150. At least one of the second slots172is located closer to the second longitudinal end154than to the first longitudinal end152. Each of the second slots172defines a plane that is oriented at an oblique angle relative to the longitudinal direction150. In use, the second slots172configured to receive bone graft or any other natural or synthetic material capable of promoting bone growth. The second slots172do not necessarily have to be filled with a bone graft or any other bone growth agent. Rather, the second slots172provide an open space to permit natural bone growth when the spacer102is disposed in the osteotomy gap40.

During natural bone growth, the natural bone can grow and fill at least a portion of the second slots172when the spacer102is disposed in the osteotomy gap40. The second slots172also facilitate cutting the spacer102. As discussed in detail below, the spacer102can be cut to decrease its length174, which is defined by the distance between the first longitudinal end152and the second longitudinal end154along the longitudinal direction150. In operation, the length174of the spacer102may have to be shortened so that the spacer102can properly fit in the osteotomy gap40. For this purpose, each of the second slots172can be configured and sized to receive at least a portion of a cutting tool, such as a saw. In operation, the saw can be inserted through one of the slots172to cut the spacer102, thereby shortening its length174. The spacer102can also be partly or entirely made of a material that can be cut with a cutting tool such as a saw. The spacer102can also include a plurality of tines173. At least some of the tines173are disposed between two slots172. The tines173can have a substantially planer configuration. In the depicted embodiment, the tines173are obliquely angle relative to the longitudinal direction150. The spacer102can be partly or entirely made of any suitable biocompatible material such as polyetheretherketone (PEEK).

With reference toFIGS. 4F-L, the TTA system100can be part of a kit that includes spacers of different sizes. Thus, the kit may include spacers with different lengths, heights, and width. For example, the kit may include spacers102a,102b,102c,102d,102e,102f, and102g. Except for their dimensions, the spacers102a,102b,102c,102d, and102eare substantially similar to the spacer102described above with respect toFIGS. 4A-E. Thus, the spacers102gand102fare substantially similar to the spacer102described above with respect toFIGS. 4A-E; however, due to size restrictions, spacers102gand102fdo not include an opening like the opening168of the spacer102. Moreover, the spacers102gand102fare smaller than the spacer102described above with respect toFIGS. 4A-E.

With reference toFIG. 5A, the spacer fixation member128is configured to couple the spacer102to the tibial body23and the advance tuberosity30in order to secure the spacer102in the osteotomy gap40. In the depicted embodiment, the spacer fixation member128can be configured as the bone plate130, and includes a body134that configured and sized to partially fit within the first slot170of the spacer102. The body134can also be referred to as the plate body. Furthermore, the body134can define the first end portion138, the second end portion140, and the intermediate fixation portion142disposed between the first end portion138and the second end portion140.

The first end portion138can be elongate along a longitudinal axis176, and can configured to be attached to the advanced tuberosity30. To facilitate attachment between the spacer fixation member128and the advanced tuberosity30, the first end portion138can be contoured and configured to conform to a lateral surface or a medial surface of the advanced tuberosity30, and can include one or more attachment locations such as fastener holes132. The fastener holes132can be configured and sized to receive the fastener136as discussed above. In the depicted embodiment, the first end portion138defines a plurality of fastener holes132. The plurality of fastener holes132allows a user to attach the spacer fixation member128to the advanced tuberosity30at different attachment locations along the first end portion138. It is contemplated, however, that the first end portion138may define only one fastener hole132.

The intermediate fixation portion142can be elongate along the longitudinal axis176and can define at least one fastener hole178that is configured to receive a fastener such as a bone anchor. If necessary, the spacer fixation member128can be cut to shorten it, and a fastener can be inserted through the fasteners hole178and into the tibial body23to couple the spacer fixation member128to the tibial body23. As discussed above, at least part of the intermediate fixation portion142can configured to be inserted in the first slot170so as to couple the spacer fixation member128to the spacer102.

The second end portion140can be elongate along a longitudinal axis178that is angularly offset relative to the longitudinal axis176. In an embodiment, the second end portion140can be contoured and configured to conform to a lateral or medial surface of the tibial body23. To facilitate attachment between the spacer fixation member128and the tibial body23, the second end portion140can include one or more attachment locations such as the fastener hole144. In the depicted embodiment, the second end portion140define only one fastener hole144. However, the second end portion140may include more than one fastener hole144. As discussed above, a fastener can be inserted through the fastener hole144and into the tibial body23to couple the spacer fixation member128to the tibial body23.

With reference toFIG. 5B, another embodiment of the spacer fixation member128ais substantially similar to the spacer fixation member128described above with respect toFIG. 5A. However, in this embodiment, the second end portion140aincludes a first section141athat is connected to the intermediate fixation portion142aand elongate along a longitudinal axis177a. The longitudinal axis177amay be substantially perpendicular to the longitudinal axis176a. The second end portion140afurther includes a second section143athat is elongated along a longitudinal axis179a. The longitudinal axis179amay be angularly offset relative to the longitudinal axis177aand the longitudinal axis176a. In operation, the second end portion140aof the spacer fixation member128acan be contoured and configured to conform to a lateral surface or a medial surface of the tibial body23to facilitate the connection of the spacer fixation member128ato that lateral or medial surface.

With reference toFIGS. 6A-6C, a spacer202in accordance with another embodiment can be positioned in the osteotomy gap40to maintain the tuberosity30in the advanced position relative to the tibial body23. The spacer202can include a spacer body248that can be partly or entirely made of a polyetheretherketone (PEEK) or any other suitable material. The spacer body248defines an upper surface203and an opposed lower surface205. The upper surface203is spaced from the lower surface along a transverse direction262. The spacer body248can include a front surface207and an opposed rear surface209. The rear surface209can be spaced from the front surface207along a longitudinal direction250. The spacer body248can define first lateral surface211and a second lateral surface213. The second lateral surface213can be spaced from the first lateral surface211along a lateral direction260.

The spacer202further defines a plurality of slots272that extend into the lower surface of the spacer body248. The slots272can be spaced apart from one another along the lateral direction260. Each of the slots272can be elongate along the transverse direction262. Moreover, each of the slots272can extend through the spacer body248from the front surface207to the rear surface209. When the spacer202is disposed in the osteotomy gap40, the slots272provide an open space to permit bone growth. The slots272also facilitate cutting of the spacer202in order to shorten its length. In addition, any suitable natural or synthetic bone growth material can be disposed in the slots272to promote bone growth when the spacer202is disposed in the osteotomy gap40. The slots272also facilitate cutting of the spacer202. As discussed above, the spacer202may be cut if necessary to properly fit in the osteotomy gap40. For instance, a cutting tool can be inserted through one of the slots272to cut the spacer202, thereby shortening the spacer202along the lateral direction260.

The spacer body248can include a plurality of resilient tines275that are spaced from one another along the lateral direction260. Each resilient tine275is disposed between two slots272. The resilient tines275allows the spacer body248to be compressed along the lateral direction260when the spacer202is disposed in the osteotomy gap40so as to allow at least a portion of the spacer body248to conform to the shape of the osteotomy gap40. The resilient tines275may also have different lengths so as to define an arch-shaped bottom lower surface205. In particular, the resilient tines275may define a concave lower surface205that allows the tines275to be compressed against one another so as to conform to the shape of the osteotomy gap40when the spacer202is disposed in the osteotomy gap40.

The spacer202can further include one or more holes270that into the spacer body248along the lateral direction260. In the depicted embodiment, the holes270extend through the spacer body248from the first lateral surface211to the second lateral surface213along the lateral direction260. When the spacer202is disposed in the osteotomy gap40, the holes270provide an open space to promote bone growth. In addition to the holes270, the spacer202may define one or more ridges273that extend into the upper surface203. In the depicted embodiment, the ridges273can be spaced from one another along the lateral direction260. The ridges273can be elongate along the longitudinal direction250. In operation, the cutting tool, such as a saw, can be inserted in one of the ridges273to cut the spacer202. Thus, the ridges273facilitate cutting of the spacer202. The ridges273also permit the spacer202to flex.

The spacer202can further define at least one fastener hole215that is configured and sized to receive a fastener133. The fastener133can be configured to couple the spacer fixation member128a(or any other spacer fixation member) to the spacer202. In the depicted embodiment, the fastener133is configured as a screw, and the fastener hole215can be a threaded hole. It is envisioned, however, that the fastener133can be configured as a nail, a pin, or any other apparatus configured to couple the spacer fixation member128ato the spacer202. To couple the spacer fixation member128ato the spacer202, the fastener133can be inserted through one of the fastener holes132aof the spacer fixation member128aand into the fastener hole215. As discussed above, the spacer fixation member128acan also be coupled to the advanced tuberosity30and the tibial body23via fasteners.

With reference toFIGS. 7A-B, a spacer302in accordance with another embodiment can be positioned in the osteotomy gap40to maintain the tuberosity30in the advanced position relative to the tibial body23. The spacer302is substantially similar to the spacer202. However, in this embodiment, the resilient tines375have substantially similar or identical lengths and, therefore, do not define a concave lower surface305. Instead, the lower surface205may have a substantially planar configuration. Moreover, the spacer302can further define recesses371, such as partial holes, that extend into the lower surface305. The recesses371can be spaced from one another along the longitudinal direction350. In operation, the recesses371provide an open space to permit bone growth when the spacer302is disposed in the osteotomy gap40.

With reference toFIGS. 8A-C, the TTA system100can also include a TTA advancement assembly400configured to guide the advancement of the tuberosity30relative to the tibial body23. As discussed in detail below, the advancement assembly400can be used to advance the tuberosity30relative to the tibial body23is described in detail below. The advancement assembly400includes an advancement member402that is configured to be coupled to the implant104, which in turn is coupled to the tuberosity30. Specifically, the advancement member402can be coupled to the proximal end portion112of the implant104. In the depicted embodiment, the advancement member402can be coupled to the implant104at the attachment location defined by the fastener hole118a. The implant104can be attached to the tuberosity30and the advancement member402. Therefore, the advancement member402can be manipulated to advance the tuberosity30(via implant104) relative to the tibial body23.

With continuing reference toFIGS. 8A-C, the advancement member402can be configured as a jig403, and can include an advancement body404. The advancement body404can be configured as a jig body or a frame. Regardless of its configuration, the advancement body404defines an attachment location such as a displacement scale hole406that is configured to securely receive a displacement scale408. Thus, the advancement assembly400can include a displacement scale408that can be used to measure the longitudinal displacement of the tuberosity30relative to the tibial body23. The displacement scale408can be removably attached to the advancement body404via the displacement scale hole408.

The displacement scale408includes a body410that includes measurement markings412that can be used to measure the longitudinal displacement of the tuberosity30relative to the tibial body23. In addition to the body410, the displacement scale408includes a connection member414that protrudes from the body410. The connection member414can be configured as a substantially cylindrical body, and can be removably disposed in the displacement scale hole406. The connection member414can include a connection body416and a ring418disposed around the connection body416. The connection body416is configured and sized to be at least partially received in the displacement scale hole406. When the connection member414is at least partially disposed in the displacement scale hole406, the ring418abuts the inner surface of the advancement body404that defines the displacement scale hole406, thereby establishing a friction fit connection between the connection member414and the advancement body404.

The advancement assembly400can further include a longitudinal distraction mechanism419that is configured to move the tuberosity30relative to the tibial body23when the advancement assembly400is coupled to the tuberosity30and the tibial body23. In the depicted embodiment, the distraction mechanism419can include a distraction arm420that is movably coupled to the advancement body404, and an actuator424such as a knob426. In operation, the distraction arm420is configured to move relative to the advancement body404upon actuation of the actuator424. Thus, the actuation of the actuator424causes the distraction arm420to move relative to the advancement body404along a longitudinal distraction axis422. In operation, the movement of the distraction arm420relative to the advancement body404causes the tuberosity30to move relative to the tibial body23when the advancement assembly400is coupled to the to the tuberosity30and the tibial body23.

As discussed above, the actuator424can be configured as a knob426. The knob426can include a knob body428, and can define a threaded hole430that is configured and sized to receive at least a portion of the distraction arm420. The threaded hole430can extend through the knob body428. The distraction arm420can include external threads432that are configured to mate with the inner threads disposed around the threaded hole430such that rotation of the knob426about the distraction arm420causes the distraction arm420to move relative to the knob426along the longitudinal distraction axis422. Hence, the distraction arm420can be configured to move relative to the advancement body404upon rotation of the knob426. While the distraction arm420can move longitudinally relative to the advancement body404, the knob426is fixed longitudinally with respect to the advancement body404.

The advancement member402can include a first attachment prong436and a second attachment prong438that are spaced apart from each other so as to define a knob channel434. The first attachment prong436and the second attachment prong438can protrude from the advancement body404. The knob channel434can be configured and sized to receive the knob426so as to longitudinally fixe the knob426to the advancement member402while allowing the knob426to rotate within the knob channel434. The knob426can be configured to rotate about the longitudinal distraction axis422. The first attachment prong436defines a distraction arm hole440that is configured to receive at least a portion of the distraction arm420. The distraction arm402can slide through the distraction arm hole440. The second attachment prong438can define a distraction arm channel442that is configured and sized to receive at least a portion of the distraction arm420. The distraction arm420can slide through the distraction arm channel442. The second prong438can also define a first stop member444that is configured to abut a second stop member446of the distraction arm420so as to limit the longitudinal movement of the distraction arm420relative to the advancement member402.

The distraction arm420can define a first end448and a second end450, the second end450, as shown in the illustrated embodiment, can in turn define the second stop member446. The first end448can be spaced from the second end450along the longitudinal distraction axis422. The distraction arm420can further define a dill guide hole452that extends through the second end450of the distraction arm420. The drill guide hole452can be configured and sized to receive a drill guide454, which can be configured as a sleeve. The drill guide454can include a drill guide body456that defines a first end460and a second end462spaced apart from each other.

The second end462can define a threaded tip464that is configured and sized to mate with the threaded fastener hole118a(FIG. 3) of the implant404so as to couple the drill guide454to the implant104. The threaded tip464can have a frusto-conical shape. The drill guide454can define a drill guide opening458that extends through the drill guide body456between the first end460and the second end462. The drill guide opening458can be configured and sized to receive a drill bit or a temporary fixation member such as a wire466. The wire466can be a Kirschner wire, and is configured to be inserted through the drill guide opening458and into the tuberosity30so as to couple the advancement assembly400to the tuberosity30when the drill guide454is coupled to the distraction arm420.

The advancement assembly400can further include an angular adjustment mechanism468that is configured to adjust the angular position of the tuberosity30with respect to the tibial body23when the advancement assembly400is coupled to the tibial body23and the tuberosity30. In the depicted embodiment, the angular adjustment mechanism468can include an angular adjustment member470that is movably coupled to the advancement body404. Specifically, the angular adjustment member470is configured to rotate about an attachment location defined along a pivot axis R. In particular, the advancement member402defines an attachment location such as a hole472. The hole472extends through the advancement body404along the pivot axis R, and is configured to receive at least a portion of a rotational actuator474such that the rotational actuator474is configured to rotate about the pivot axis R within the hole472.

The rotational actuator474can be configured as a knob473, and includes an attachment member476that is configured to mate with an attachment member480of the angular adjustment member470so as to couple rotational actuator474to the angular adjustment member470. The attachment member476can be configured as an externally threaded body478, and the attachment member480can be configured as a threaded hole482. The threaded hole482can be configured to mate with the externally threaded body478so as to couple the rotational actuator474to the angular adjustment member470. The angular adjustment member470can be configured as an angular scale.

The angular adjustment member470can also be angularly fixed relative to the angular body404by tightening the rotational actuator474. For example, the rotation of the rotational actuator474about the pivot axis R in a first direction tightens the externally threaded body478in the threaded hole482, thereby angularly fixing the angular adjustment member470with respect to the advancement body404. Conversely, the rotation of the rotational actuator474in a second direction (opposite to the first direction) about the pivot axis R loosens the externally threaded body478disposed in the threaded hole482, thereby allowing the angular adjustment member470to rotate about the pivot axis R with respect to the advancement body404.

The angular adjustment member470includes an angular scale body484that is elongate along a longitudinal direction486. The angular scale body484can have a substantially planar configuration, and defines a first scale end488and a second scale end490. The second scale end490is spaced from the first scale end488along the longitudinal direction486. The threaded hole482can be located at or close to the first scale end488. The angular adjustment member470can further include a contact member494that protrudes from angular scale body484along a lateral direction492. The lateral direction492can be substantially perpendicular to the longitudinal direction486. The contact member494can have a substantially planar configuration, and is configured and sized to be disposed in the osteotomy gap40. The contact member494can be a brace, a blade or any apparatus suitable to contact the tibial tuberosity30, the tibial body23, or both, when positioned in the osteotomy gap40.

The angular adjustment member470can further include angular markings491disposed along the second scale end490. The angular markings491help users determine the angular orientation of the contact member494relative to the advancement body404. In particular, the angular markings491are disposed along an arc, which center is defined by the attachment member480. The angular adjustment member470further includes a plurality of openings or recesses496disposed adjacent the angular markings491. The openings496spaced from one another along an arc, which center is defined by the attachment member480. Each of the openings496is configured and sized to receive a post498that protrudes from the advancement body404in the lateral direction492. The engagement between the post498and each of the openings496allows a user to adjust the angular orientation of the angular adjustment member470at predetermined increments.

The angular adjustment member470further defines an arc-shaped opening499that extends through the angular scale body484along the lateral direction492. The arc-shaped opening499can be elongate along an arc, which center is defined by the attachment member480. In the depicted embodiment, the arc-shaped opening499is configured and sized to receive a temporary fixation member such as a wire497. The wire497can be a Kirschner wire, and is configured to be inserted through the arc-shaped opening499, an opening495of the advancement member402, and into a portion of the tibial body23, such as the tibial diaphysis, so as to couple the advancement assembly400to the tibial body23. As discussed above, the advancement member402defines an opening495that extends through the advancement body404in the lateral direction492. The opening495is substantially aligned with the arc-shaped opening499, and can be configured and sized to receive the wire497. While using the TTA system100, the user, such as a surgeon, may observe its actions along a viewing direction72. Thus, the user's line of sight when using the TTA system100extends along the viewing direction72.

With reference toFIG. 9, the conventional common tangent method can be used to determine longitudinal and angular advancement of the tuberosity30relative to the tibial body23. The common tangent method can be performed by a processor in a computer. Alternatively, the common tangent method can be performed by placing transparent overlays over an x-ray film. An example of the common tangent method includes all or some of the following steps. First, a first circle502is drawn around the articulating surface of the femur24. A second circle504is drawn around the articulating surface of the tibia22.

The first and second circles502and504should touch, for example such that the first and second circles502and504are tangent to each other. Then, a line506is drawn connecting the center508of the first circle502and the center510of the second circle504. Next, a common tangent line CTL is drawn. The line CTL is tangential to the first circle502and the second circle504and perpendicular to the line506. The line CTL represents the slope of the tibial plateau28and the direction of the cranial tibial thrust.

Next, the length of the patellar tendon32(shown inFIG. 1) is measured. The length of the patellar tendon32is defined between the distal pole P of the patella511wherein the patellar tendon32originates and the location in the tuberosity30where the patellar tendon32is inserted. The location where the patellar tendon32inserts into the tuberosity30is referred to in the present disclosure as the insertion point I. The length of the patellar tendon32can then be recorded as distance PI. Then, a line512is drawn from the distal pole P of the patella511to determine the target point T. The line512is perpendicular to the line CTL and has a length that is equal to the distance PI. The target point T is the desired location of the tuberosity30after the TTA procedure has been performed. That is, when the tibial tuberosity30is fixed at the target point T, the tibiofemoral sheer force is neutralized when weight is applied to the knee joint20, thereby reducing or altogether bypassing the anatomical function of the CCL.

Next, the osteotomy line514is identified. The osteotomy line514can be disposed between the Gerdy's Tubercle (i.e., the lateral tubercle of the tibia) to the distal aspect of the tibial tuberosity30. The distance D1from the insertion point I to the most proximal end of the osteotomy line514is measured. A distance D2from the insertion point I to most distal end of the osteotomy line514is measured. Next, a line TI is drawn from the target point T to the insertion point I. The line TI can then be extended to the osteotomy line514. The advancement distance AD from the target point T to the insertion point I is measured. Then, the advancement angle AA is determined by measuring the acute angle between the line TI and the osteotomy line514.

Next, in a computer, the virtual model of the implant104is placed over the virtual representation of the tibia22and femur24to determine the correct size of the implant104. Alternatively, the size of the implant104can be determined by placing an overlay that represents the implant104over a radiograph of the tibia22and the femur24. In this process, the proximal end portion112of the implant104should be parallel to the cranial edge of the tuberosity. Also, in this process, the fastener hole118ashould be placed at a predetermined distance (e.g., from about 1 to 2 millimeters) caudal to the insertion point I along the line TI. The steps described above can be defined as a pre-operative plan.

Upon completion of the pre-operative plan, the osteotomy may be performed. In particular, the osteotomy can be conducted from the distal aspect of the tibial tuberosity in accordance with the pre-operative plan described above. The osteotomy can be made with any suitable cutting tool. However, the osteotomy is stopped at a predetermined distance (e.g., about 3 to 4 millimeters) from the proximal cortex of the tibial tuberosity30.

Referring toFIGS. 8A-9, after partially performing the osteotomy, the drill guide454is at least partially inserted through the dill guide hole452. Then, the second end462of the drill guide452is secured in the fastener hole118aof the implant104as described in detail above. The angular adjustment member470is then rotated relative to the advancement body404such that the post498is aligned with the marking that is equal to the predetermined advancement angle AA. The angular adjustment member470is then fixed relative to the advancement body404by tightening the rotational actuator474in the threaded hole482as described above.

The contact member494is inserted in the osteotomy, and then the blade is moved further into the osteotomy until the distraction arm420is disposed over the insertion point I as determined in the pre-operative planning. The wire466is then inserted through the drill guide454and the fastener hole118a, and into tibial tuberosity30in order to secure the advancement assembly400and the implant104to the tibial tuberosity30. The wire466should be oriented in the lateral direction492. Next, the wire497can be inserted through the opening495and the arc-shaped opening499and into a portion of the tibial body23, such as the tibial diaphysis, in order to secure the advancement assembly400to the tibial body23. The actuator424is actuated to move distraction arm420toward the tibial body23in order to compress the osteotomy until a light resistance is felt. The distraction arm420can be moved toward the tibial body23by turning the knob426in a first direction. At this point, the user should record the starting point of the distraction arm420by noting the location of the first end448of the distraction arm420in relation to the markings412of the displacement scale408. The implant104is then aligned with the cranial aspect of the tibial tuberosity30as determined in the pre-operative plan, and the fastener can be inserted in at least one of the fastener holes118b,118c, or118d, to prevent rotation of the implant104.

Alternatively, the advancement assembly400and the implant104can be coupled to the tibial tuberosity30and the tibial body23by performing the following steps. First, a first drill guide, which can be identical to the drill guide454, is at least partially inserted in the fastener hole118aso as to couple the drill guide454to the implant104. The implant104is then placed on the tibial tuberosity30in accordance with the pre-operative plan. Then, the wire466is inserted through the drill guide454and into the tibial tuberosity30, while leaving the first drill guide454coupled to the implant104and holding the implant104against the tibial tuberosity30. The implant104is rotated so that the proximal end portion112of the implant104is substantially parallel to the cranial edge of the tuberosity.

A second drill guide, which can be identical to the drill guide454, is then inserted through the fastener hole118dso as to couple the second drill guide to the implant104at the fastener hole118d. A drill bit can be inserted through the second drill guide and the fastener hole118dto drill hole into the tibial tuberosity30. A fastener, such as a locking screw, is then inserted in to the drilled hole in the tibial tuberosity30. The angular adjustment member470is then adjusted at the advancement angle AA as predetermined in the pre-operative plan. The knob473is then tightened to fix the angular orientation of the angular adjustment member470with respect to the advancement body404. The first drill guide is then decoupled from the implant104and withdrawn from the animal. Then, the advancement member404is advanced over the wire466such that the wire466is disposed in the drill guide hole452. The distraction arm420can be moved away from the tibial body23so that the contact member494can be inserted in the osteotomy. The contact member494is then inserted in the osteotomy. Next, the wire497can be inserted through the opening495and the arc-shaped opening499and into a portion of the tibial body23such as the tibial diaphysis.

After coupling the advancement assembly400and the implant104to the tibial tuberosity30and the tibial body123, the osteotomy can be completed by cutting all the way through the proximal cortex of the tibial tuberosity30. The distraction arm420is then moved (via the actuator424) away from the tibial body23a distance equal to the advancement distance AD. The displacement scale408can be used to measure the displacement of the distraction arm420. To this end, the user can gradually turn the knob426in a second direction until the first end448of the distraction arm420moves a distance that is substantially equal to the advancement distance AD as measured by the markings412. Thus, the translation of the distraction arm420a predetermined distance (i.e., advancement distance AD) causes the advancement assembly400(for example the displacement scale408) to provide an indication that the tuberosity has advanced from the first position to the advanced position.

Then, the tibial tuberosity30is rotated relative to the tibial body23until its distal end31contact a surface25of the tibial body23that defines a distal end of osteotomy seen inFIG. 9. The fasteners124are then inserted through the fastener holes122aand122band into the tibial body23to couple the distal end portion114of the implant104to the tibial body23. The osteotomy gap40is then measured to determine the appropriate spacer size and spacer fixation member size. The spacer fixation member128is then coupled to the spacer102as described above.

Then, the spacer102is then inserted in the osteotomy gap40to verify that the appropriate size was selected. The advancement assembly400may be withdrawn from the animal to expand the working space. If the proper spacer102was selected, the spacer102is cut (if necessary) so that it conforms to the size of the osteotomy gap40. The spacer102and the spacer fixation member128can then be secured in the osteotomy gap40by inserting the fastener136through the fastener holes132and into the tibial tuberosity30and by inserting another fastener136through the fastener holes144and into the tibial body23. If the advancement assembly400has not been removed from the animal yet, the advancement assembly400can be decoupled from the tibial tuberosity30and the tibial body23and removed from the animal.

The advancement assembly400can be decoupled from the tibial tuberosity30and the tibial body23by removing the wires466and497from the tibial tuberosity30and the tibial body23, respectively. Once decoupled, the advancement assembly400can be removed from the animal. A drill bit can be inserted through the fastener hole118ato create a drill hole that is appropriate for the fastener120. Then, the fastener120can be inserted through the fastener hole118aand into the tibial tuberosity30to secure the implant104to the tibial tuberosity30. Additional fasteners120can be inserted through the fasteners holes118b,118c, and118dand into tibial tuberosity30as deemed necessary for a secure connection between the implant104and the tibial tuberosity30.

Referring toFIGS. 3 and 10A-10I, in another embodiment, the TTA system100can include an alternate embodiment of the implant104(shown inFIG. 3), such as implant604(shown inFIGS. 10A-10H). The implant604can be constructed as a bone fixation member606, such as a bone plate608. In the depicted embodiment, the implant604includes an implant body610that includes a proximal end portion612, an opposed distal end portion614, and an intermediate implant portion616disposed between the proximal end portion612and the distal end portion614. The proximal end portion612of the implant body610can be configured to be attached to the tuberosity30that has been advanced along with the patellar tendon32(shown inFIG. 1) in a direction cranially relative to the tibial body23from a first position to an advanced position. The distal end portion614of the implant body610can be configured to be attached to the tibial body23.

It should be appreciated that the patellar tendon32is attached to the tuberosity30at an anatomical attachment location43, and that the tuberosity30can be resected, and thus separated, from the tibial body23at a location caudal of the attachment location43such that the patellar tendon32, including the attachment location43, is advanced along with the separated tuberosity30from the first position to the advanced position. The proximal end portion612, the distal end portion614, and the intermediate implant portion616can collectively be a monolithic structure. Alternatively, proximal end portion612, the distal end portion614, and the intermediate implant portion616can be discrete components that are connected to each other to form the implant body610.

The proximal end portion612can be contoured and configured to conform to a medial surface or lateral surface of the tuberosity30to facilitate attachment of the implant604to the tuberosity30. Moreover, the proximal end portion612includes one or more attachment locations such as fastener holes. In the depicted embodiment, the proximal end portion612of the implant body610includes four fastener holes618a,618b,618c, and618d. However, the proximal end portion612may include more or fewer fastener holes. Each fastener hole618a,618b,618c, and618dextends through the implant body610, and is configured and sized to receive a fastener120, such as a bone anchor, that is capable of attaching the implant604to the tuberosity30. The fastener holes618a,618b,618c, and618dcan be threaded holes that are configured to receive a bone screw. In another embodiment the fasteners holes618a,618b,618c, and618dcan be conical thread holes that are configured receive bone screws with a threaded or non-threaded conical head.

The insertion of fasteners120through fastener holes618a,618b,618c, and618dcauses the proximal end portion612to be attached to the tuberosity30. The fastener holes618a,618b,618c, and618dmay be spaced apart from one another and substantially aligned along a first longitudinal axis L1′ that extends substantially parallel to the direction of elongation of the tuberosity30when the implant604is attached to the advanced tuberosity30. In one embodiment the proximal end portion112can be elongate along the longitudinal axis L1′.

The distal end portion614can be contoured and configured to conform to a medial surface or a lateral surface of the tibial body23to facilitate attachment of the implant604to the tibial body23. Further, the distal end portion614of the implant body610can include one or more anchor locations such as fastener holes. In the illustrated embodiment, the distal end portion614includes fastener holes622a,622b,622c, and622d. Each of the fastener holes622a,622b,622c, and622dcan be configured and sized to receive a fastener124, such as a bone anchor, capable of attaching the implant604to the tibial body23.

The insertion of fasteners124through the fastener holes622a,622b,622cand622dcauses the distal end portion614to be attached to the tibial body23. The fastener holes622a,622b,622c, and622dmay be spaced apart from one another and substantially aligned along a second longitudinal axis L2′. In one embodiment the distal end portion614can be elongate along the second longitudinal axis L2′. The first longitudinal axis L1′ may be angularly offset from the second longitudinal axis L2′ such that an offset angle OA is defined. The first and second longitudinal axes L1′ and L2′ can be offset such that offset angle OA is between about 170 degrees and about 130 degrees. In another embodiment the first and second longitudinal axes L1′ and L2′ can be offset such that offset angle OA is about 150 degrees. In another embodiment the offset angle OA is about 180 degrees (or 0 degrees) such that the first and second longitudinal axes L1′ and L2′ are parallel or not angularly offset.

The intermediate implant portion616of the implant body610can be substantially curved. Alternatively, the intermediate implant portion616may be substantially straight and elongated along an axis that is either angularly offset from or parallel to the second longitudinal axis L2′. Although the drawings do not show attachment locations, such as fastener holes, in the intermediate implant portion616, it is envisioned that the intermediate implant portion616may include one or more fastener holes or any other suitable attachment feature. The intermediate implant portion616extends between the proximal end portion612and the distal end portion614and is shaped so as to space the proximal end portion612cranially with respect to the distal end portion614an amount, or a distance, sufficient so as to maintain the tuberosity30in the advanced position.

The implant body610can further define a first surface626and a second surface628that is opposite the first surface626. In one embodiment, the first surface626is configured to face a tibial body23and a tuberosity30of a tibia22, and the second surface628is configured to face away from the tibial body23and the tuberosity30, when the implant604is implanted adjacent to a tibia22. In another embodiment, the second surface628is configured to face a tibial body23and a tuberosity30of a tibia22, and the first surface626is configured to face away from the tibial body23and the tuberosity30, when the implant604is implanted adjacent to a tibia22.

The implant body610can define a thickness measured between the first surface626and the second surface628. In one embodiment, the thickness of the plate can be constant along the implant body610, for example as shown inFIG. 3. In another embodiment, the thickness of the implant body610can vary. For example the implant body610can define a proximal portion thickness T1, a distal portion thickness T2, and an intermediate portion thickness T3. As stated above, the proximal portion thickness T1, the distal portion thickness T2, and the intermediate portion thickness T3can all be substantially equal. In another embodiment, the proximal portion thickness T1, the distal portion thickness T2, and the intermediate portion thickness T3can be substantially unequal. For example, the intermediate implant portion616can include a thinned out or necked portion630that defines an intermediate portion thickness T3that is less than at least one (or alternatively, both) of the proximal and distal portion thicknesses T1and T2. The necked portion630and reduced intermediate portion thickness T3can allow for the implant604to be bent or flexed such that first surface626corresponds more closely with the surfaces of the tibial body23and the tuberosity30then if the implant body610had a constant thickness. In another embodiment, each of the proximal portion thickness T1, the distal portion thickness T2, and the intermediate portion thickness T3, can be either greater than, less than, or equal to any of the other portion thicknesses.

In another embodiment the proximal end portion612, the distal end portion614, or both can include a thinned out or necked portion630. The necked portion630of any of the proximal end portion612, the distal end portion614, or the intermediate portion616may only comprise a portion of the respective implant portion such that the respective thickness T1, T2, or T3varies within that implant portion. The necked portion630can include at least one transition632, for example two transitions632, where the thickness of the implant body610changes. As shown in the illustrated embodiment, the transition632can be a radiused surface633resulting in a gradual change in thickness. In another embodiment the transition632can include a step resulting in a sudden change in thickness. In another embodiment, the transition632can include both a radiused surface633and a step surface resulting in a partial gradual change in thickness and a partial sudden change in thickness. In another embodiment the implant body610can include transitions632that are different, for example one transition632with a radiused surface633and another transition632with a step surface.

The implant body610can include a first side surface634and a second side surface636opposite the first side surface634. The first and second side surfaces634and636can each extend between the first surface626and the second surface628in one direction, and between the proximal end portion612and the distal end portion614in another direction. The implant body610can define a width measured between the first side surface634and the second side surface636. In one embodiment, the width of the plate can be constant along the implant body610, for example as shown inFIG. 3. In another embodiment, the width of the implant body610can vary. For example the implant body610can define a proximal portion width W1, a distal portion width W2, and an intermediate portion width W3.

As stated above, the proximal portion width W1, the distal portion width W2, and the intermediate portion width W3can all be substantially equal. In another embodiment, the proximal portion width W1, the distal portion width W2, and the intermediate portion width W3can be substantially unequal. For example, the implant body610can include a neck638between the proximal end portion612and the intermediate implant portion616, such that the width of the implant body610changes along the neck638. As shown in the illustrated embodiment, the width of the implant body transitions along the neck638from the greater intermediate portion width W3down to the smaller proximate portion width W1. In another embodiment, each of the proximal portion width W1, the distal portion width W2, and the intermediate portion width W3, can be either greater than, less than, or equal to any of the other portion widths.

In one embodiment the implant body610can include at least one scalloped portion640. The scalloped portion640can include a peripheral side wall642and a raised surface644. In one embodiment the raised surface644extends out from the first surface626and can be configured to face a tibial body23and a tuberosity30of a tibia22when the implant604is implanted adjacent to a tibia22. In the illustrated embodiment, the distal end portion614includes scalloped portions640a,640b,640c, and640d. In one embodiment the scalloped portion640can include a partial peripheral side wall642dthat does not completely define the outer boundary of the scalloped portion640d.

As shown in the illustrated embodiment, the implant body610can include adjacent scalloped portions640, for example scalloped portions640band640cor scalloped portions640cand640d. The adjacent scalloped portions640can be separated by a gap646that is defined by the facing portions of the peripheral side walls642, for example642band642c. The gap646can extend through an entirety of the width of the respective implant portion (proximal portion width W1, distal portion width W2, intermediate portion width W3) that carries the adjacent scalloped portions640. In an alternative embodiment the gap646can extend only partially through the width of the respective implant portion that carries the adjacent scalloped portions640. The gap646can vary in size along the width of the implant portion that carries the adjacent scalloped portions640. For example, as shown in the illustrated embodiment, the gap646can be wider at the ends of the gap646along the width (adjacent the first and second side walls634and636) and narrower around the middle of the gap646along the width.

The facing portions of the peripheral side walls642band642cof the adjacent scalloped portions640band640ccan include a tapered portion, a substantially parallel portion, or both. In the substantially parallel portion the peripheral side walls642band642cof the adjacent scalloped portions640band640cextend along the width substantially parallel to each other such that the size of the gap646is substantially constant. In the tapered portion the peripheral side walls642band642cof the adjacent scalloped portions640band640cflare away from each other along the width. As shown in the illustrated embodiment, the peripheral side walls642band642cof the adjacent scalloped portions640band640ccan flare away from each other linearly such that a first gap angle648is defined. The first gap angle648can be from about 45 degrees to about 135 degrees, or in another embodiment the first gap angle648can be about 90 degrees. In another embodiment the peripheral side walls642band642cof the adjacent scalloped portions640band640ccan flare away from each other nonlinearly.

In addition to extending along the width of the plate, the gap646can extend along the thickness of the plate, for example the gap646can extend into the first surface626toward the second surface628. In one embodiment the peripheral side walls642band642cof the adjacent scalloped portions640band640cflare away from each other along the thickness of the implant body610. As shown in the illustrated embodiment, the peripheral side walls642band642cof the adjacent scalloped portions640band640ccan flare away from each other linearly such that a second gap angle650is defined. The second gap angle650can be from about 0 degrees to about 60 degrees, or in another embodiment the second gap angle650can be about 30 degrees. In another embodiment the peripheral side walls642band642cof the adjacent scalloped portions640band640ccan flare away from each other nonlinearly along the thickness.

Referring toFIGS. 3 and 11A-11I, in another embodiment, the TTA system100can include another embodiment of the implant104(shown inFIG. 3), such as implant704(shown inFIGS. 11A-11H). The implant704can be constructed as a bone fixation member706, such as a bone plate708. In the depicted embodiment, the implant704includes an implant body710that includes a proximal end portion712, an opposed distal end portion714, and an intermediate implant portion716disposed between the proximal end portion712and the distal end portion714. The proximal end portion712of the implant body710can be configured to be attached to the tuberosity30that has been advanced along with the patellar tendon32(shown inFIG. 1) in a direction cranially relative to the tibial body23from a first position to an advanced position. The distal end portion714of the implant body710can be configured to be attached to the tibial body23.

It should be appreciated that the patellar tendon32is attached to the tuberosity30at an anatomical attachment location43, and that the tuberosity30can be resected, and thus separated, from the tibial body23at a location caudal of the attachment location43such that the patellar tendon32, including the attachment location43, is advanced along with the separated tuberosity30from the first position to the advanced position. The proximal end portion712, the distal end portion714, and the intermediate implant portion716can collectively be a monolithic structure. Alternatively, proximal end portion712, the distal end portion714, and the intermediate implant portion716can be discrete components that are connected to each other to form the implant body710.

The proximal end portion712can be contoured and configured to conform to a medial surface or lateral surface of the tuberosity30to facilitate attachment of the implant704to the tuberosity30. Moreover, the proximal end portion712includes one or more attachment locations such as fastener holes. In the depicted embodiment, the proximal end portion712of the implant body710includes four fastener holes718a,718b,718c, and718d. However, the proximal end portion712may include more or fewer fastener holes. Each fastener hole718a,718b,718c, and718dextends through the implant body710, and is configured and sized to receive a fastener120, such as a bone anchor, that is capable of attaching the implant704to the tuberosity30. The fastener holes718a,718b,718c, and718dcan be threaded holes that are configured to receive a bone screw. In another embodiment the fasteners holes718a,718b,718c, and718dcan be conical thread holes that are configured receive bone screws with a threaded or non-threaded conical head.

The insertion of fasteners120through fastener holes718a,718b,718c, and718dcauses the proximal end portion712to be attached to the tuberosity30. The fastener holes718a,718b,718c, and718dmay be spaced apart from one another and substantially aligned along a first longitudinal axis L1″ that extends substantially parallel to the direction of elongation of the tuberosity30when the implant704is attached to the advanced tuberosity30. In one embodiment the proximal end portion112can be elongate along the longitudinal axis L1″.

The distal end portion714can be contoured and configured to conform to a medial surface or a lateral surface of the tibial body23to facilitate attachment of the implant704to the tibial body23. Further, the distal end portion714of the implant body710can include one or more anchor locations such as fastener holes. In the illustrated embodiment, the distal end portion714includes fastener holes722a,722b,722c, and722d. Each of the fastener holes722a,722b,722c, and722dcan be configured and sized to receive a fastener124, such as a bone anchor, capable of attaching the implant704to the tibial body23.

The insertion of fasteners124through the fastener holes722a,722b,722c, and722dcauses the distal end portion714to be attached to the tibial body23. The fastener holes722a,722b,722c, and722dmay be spaced apart from one another and substantially aligned along a second longitudinal axis L2″. In one embodiment the distal end portion714can be elongate along the second longitudinal axis L2″. The first longitudinal axis L1″ may be angularly offset from the second longitudinal axis L2″ such that an offset angle OA′ is defined. The first and second longitudinal axes L1″ and L2″ can be offset such that offset angle OA′ is between about 180 degrees and about 160 degrees. In another embodiment the first and second longitudinal axes L1″ and L2″ can be offset such that offset angle OA′ is about 170 degrees. In another embodiment the offset angle OA′ is 180 degrees (or 0 degrees) such that the first and second longitudinal axes L1″ and L2″ are parallel or not angularly offset.

The intermediate implant portion716of the implant body710can be substantially curved. Alternatively, the intermediate implant portion716may be substantially straight and elongated along an axis that is either angularly offset from or parallel to the second longitudinal axis L2″. Although the drawings do not show attachment locations, such as fastener holes, in the intermediate implant portion716, it is envisioned that the intermediate implant portion716may include one or more fastener holes or any other suitable attachment feature. The intermediate implant portion716extends between the proximal end portion712and the distal end portion714and is shaped so as to space the proximal end portion712cranially with respect to the distal end portion714an amount, or a distance, sufficient so as to maintain the tuberosity30in the advanced position.

The implant body710can further define a first surface726and a second surface728that is opposite the first surface726. In one embodiment, the first surface726is configured to face a tibial body23and a tuberosity30of a tibia22, and the second surface728is configured to face away from the tibial body23and the tuberosity30, when the implant704is implanted adjacent to a tibia22. In another embodiment, the second surface728is configured to face a tibial body23and a tuberosity30of a tibia22, and the first surface726is configured to face away from the tibial body23and the tuberosity30, when the implant704is implanted adjacent to a tibia22.

The implant body710can define a thickness measured between the first surface726and the second surface728. In one embodiment, the thickness of the plate can be constant along the implant body710, for example as shown inFIG. 3. In another embodiment, the thickness of the implant body710can vary. For example the implant body710can define a proximal portion thickness T1′, a distal portion thickness T2′, and an intermediate portion thickness T3′. As stated above, the proximal portion thickness T1′, the distal portion thickness T2′, and the intermediate portion thickness T3′ can all be substantially equal. In another embodiment, the proximal portion thickness T1′, the distal portion thickness T2′, and the intermediate portion thickness T3′ can be substantially unequal. For example, the intermediate implant portion716can include a thinned out or necked portion730that defines an intermediate portion thickness T3′ that is less than at least one (or alternatively, both) of the proximal and distal portion thicknesses T1′ and T2′. The necked portion730and reduced intermediate portion thickness T3′ can allow for the implant704to be bent or flexed such that first surface726corresponds more closely with the surfaces of the tibial body23and the tuberosity30then if the implant body710had a constant thickness. In another embodiment, each of the proximal portion thickness T1′, the distal portion thickness T2′, and the intermediate portion thickness T3′, can be either greater than, less than, or equal to any of the other portion thicknesses.

In another embodiment the proximal end portion712, the distal end portion714, or both can include a thinned out or necked portion730. The necked portion730of any of the proximal end portion712, the distal end portion714, or the intermediate portion716may only comprise a portion of the respective implant portion such that the respective thickness T1′, T2′, or T3′ varies within that implant portion. The necked portion730can include at least one transition732, for example two transitions732, where the thickness of the implant body710changes. As shown in the illustrated embodiment, the transition732can be a radiused surface733resulting in a gradual change in thickness. In another embodiment the transition732can include a step resulting in a sudden change in thickness. In another embodiment, the transition732can include both a radiused surface733and a step surface resulting in a partial gradual change in thickness and a partial sudden change in thickness. In another embodiment the implant body710can include transitions732that are different, for example one transition732with a radiused surface733and another transition732with a step surface.

The implant body710can include a first side surface734and a second side surface736opposite the first side surface734. The first and second side surfaces734and736can each extend between the first surface726and the second surface728in one direction, and between the proximal end portion712and the distal end portion714in another direction. The implant body710can define a width measured between the first side surface734and the second side surface736. In one embodiment, the width of the plate can be constant along the implant body710, for example as shown inFIG. 3. In another embodiment, the width of the implant body710can vary. For example the implant body710can define a proximal portion width W1′, a distal portion width W2′, and an intermediate portion width W3′.

As stated above, the proximal portion width W1′, the distal portion width W2′, and the intermediate portion width W3′ can all be substantially equal. In another embodiment, the proximal portion width W1′, the distal portion width W2′, and the intermediate portion width W3′ can be substantially unequal. For example, the implant body710can include a neck738between the proximal end portion712and the intermediate implant portion716, such that the width of the implant body710changes along the neck738. As shown in the illustrated embodiment, the width of the implant body transitions along the neck738from the greater intermediate portion width W3′ down to the smaller proximate portion width W1′. In another embodiment, each of the proximal portion width W1′, the distal portion width W2′, and the intermediate portion width W3′, can be either greater than, less than, or equal to any of the other portion widths.

In one embodiment the implant body710can include at least one scalloped portion740. The scalloped portion740can include a peripheral side wall742and a raised surface744. In one embodiment the raised surface744extends out from the first surface726and can be configured to face a tibial body23and a tuberosity30of a tibia22when the implant704is implanted adjacent to a tibia22. In the illustrated embodiment, the distal end portion714includes scalloped portions740a,740b,740c, and740d. In one embodiment the scalloped portion740can include a partial peripheral side wall742dthat does not completely define the outer boundary of the scalloped portion740d.

As shown in the illustrated embodiment, the implant body710can include adjacent scalloped portions740, for example scalloped portions740band740cor scalloped portions740cand740d. The adjacent scalloped portions740can be separated by a gap746that is defined by the facing portions of the peripheral side walls742, for example742band742c. The gap746can extend through an entirety of the width of the respective implant portion (proximal portion width W1′, distal portion width W2′, intermediate portion width W3′) that carries the adjacent scalloped portions740. In an alternative embodiment the gap746can extend only partially through the width of the respective implant portion that carries the adjacent scalloped portions740. The gap746can vary in size along the width of the implant portion that carries the adjacent scalloped portions740. For example, as shown in the illustrated embodiment, the gap746can be wider at the ends of the gap746along the width (adjacent the first and second side walls734and736) and narrower around the middle of the gap746along the width.

The facing portions of the peripheral side walls742band742cof the adjacent scalloped portions740band740ccan include a tapered portion, a substantially parallel portion, or both. In the substantially parallel portion the peripheral side walls742band742cof the adjacent scalloped portions740band740cextend along the width substantially parallel to each other such that the size of the gap746is substantially constant. In the tapered portion the peripheral side walls742band742cof the adjacent scalloped portions740band740cflare away from each other along the width. As shown in the illustrated embodiment, the peripheral side walls742band742cof the adjacent scalloped portions740band740ccan flare away from each other linearly such that a first gap angle748is defined. The first gap angle748can be from about 45 degrees to about 135 degrees, or in another embodiment the first gap angle748can be about 90 degrees. In another embodiment the peripheral side walls742band742cof the adjacent scalloped portions740band740ccan flare away from each other nonlinearly.

In addition to extending along the width of the plate, the gap746can extend along the thickness of the plate, for example the gap746can extend into the first surface726toward the second surface728. In one embodiment the peripheral side walls742band742cof the adjacent scalloped portions740band740cflare away from each other along the thickness of the implant body710. As shown in the illustrated embodiment, the peripheral side walls742band742cof the adjacent scalloped portions740band740ccan flare away from each other linearly such that a second gap angle750is defined. The second gap angle750can be from about 0 degrees to about 45 degrees, or in another embodiment the second gap angle750can be about 10 degrees. In another embodiment the peripheral side walls742band742cof the adjacent scalloped portions740band740ccan flare away from each other nonlinearly along the thickness.

It should be noted that the illustrations and discussions of the embodiments shown in the figures are for exemplary purposes only, and should not be construed limiting the disclosure. One skilled in the art will appreciate that the present disclosure contemplates various embodiments. It should be further appreciated that the features and structures described and illustrated in accordance one embodiment can apply to all embodiments as described herein, unless otherwise indicated. Additionally, it should be understood that the concepts described above with the above-described embodiments may be employed alone or in combination with any of the other embodiments described above.