US20100198224A1 - Prosthesis and Implementation System - Google Patents

Abstract

A prosthesis for replacing a selected portion of the anatomy is disclosed. Also disclosed is an exemplary method and apparatus for performing a procedure. The procedure can be minimally or less invasive.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application is a divisional of U.S. patent application Ser. No. 11/444,268 filed on May 31, 2006. The entire disclosure of the above application is incorporated herein by reference.
FIELD
• The present disclosure relates generally to a method and apparatus for performing an orthopedic procedure, and particularly to a method and apparatus and prosthesis for a distal femoral procedure.
BACKGROUND
• The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
• Generally, portions of the anatomy, such as a human anatomy, include bony portions that can articulate relative to one another in joints. At the joints, the articulations provide movement of the various bony portions relative to one another to allow for movement of the anatomy and mobility thereof. For example, a femur can articulate with a tibia at a knee joint to allow for movement of the legs of an anatomy.
• The natural anatomy generally allows for substantially smooth and pain free articulation at the various joints in the anatomy. For various reasons, such as injury, disease, and for other reasons, the articulations may become damaged or painful. The damaged articulations, in certain circumstances, can be replaced to substantially return the anatomy to its natural articulation.
• To perform a procedure to allow for natural articulation to replace a damaged joint, it may be desirable to substantially minimize the amount of intrusion of the soft tissue surrounding the joint. Such reduced invasive procedure can be desirable to achieve various results. Therefore, it is desirable to provide a prosthesis and system allowing for implantation of a prosthesis in a substantially less invasive manner.
SUMMARY
• A method and apparatus is disclosed for performing a procedure on a portion of the anatomy, for example, in a knee including a distal femoral portion, to prepare a portion of the anatomy for an implantation. The preparation of the distal femur, for example, can include resecting various portions of the distal femur to prepare it for implantation of a prosthesis. Also disclosed is a prosthesis that is provided to interconnect with the prepared portions of the anatomy, such as the distal femoral portion, in a selected manner.
• The method and apparatus for preparing the distal femur can be used in a substantially less invasive or minimally invasive procedure to reduce trauma to soft tissue surrounding the distal femur. Also natural and/or healthy bone can be conserved during implantation. Likewise, alternative instruments and methods can be used for preparing an anatomy for implantation. For example, a posterior chamfer resection can be avoided with selected milling systems and techniques disclosed herein.
• The prosthesis can also be provided to interconnect with the distal femur after preparation of the distal femur in a less invasive manner. The prosthesis can be provided to interconnect with the femur in a substantially complete contact with the femur to allow for an efficient transfer of forces through the prosthesis to the femur.
• According to various embodiments a prosthesis for positioning in a selected portion of an anatomy is disclosed. The prosthesis can include a first portion defining a substantially planar surface operable to fixedly engage a first surface of the anatomy. The prosthesis can also include a second portion defining a curved surface operable to engage a second surface of the anatomy. The prosthesis can be formed from one or more pieces.
• According to various embodiments a system for positioning a prosthesis relative to a selected portion of an anatomy is disclosed. The system can include a mill operable to mill the anatomy and a mill guide operable to guide the mill relative to the anatomy. A mill guide placement system can also be provided to assist in a positioning of the mill guide. Further, an alignment instrument operable to align at least one of the mill guide, the mill guide placement system, or combinations thereof relative to the anatomy can be provided and used.
• According to various embodiments, a method of positioning a prosthesis relative to a bone in an anatomy is disclosed. The method can include forming a first curved surface on a first portion of the bone and forming a planar surface on the bone. An implant can be positioned to mate, in a selected manner, with the first curved surface and the planar surface.
• Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
DRAWINGS
• The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
• FIG. 1 is an exploded plan of view of an instrument assembly according to various embodiments;
• FIG. 2 is a perspective view of a guide block according to various embodiments;
• FIG. 3A is a perspective back view of a prosthesis according to various embodiments;
• FIG. 3B is a perspective top view of a prosthesis according to various embodiments;
• FIG. 3C is a cross-section view alongline3C-3C fromFIG. 3B;
• FIG. 3D is a cross-section view alongline3D-3D fromFIG. 3B;
• FIG. 4 is a perspective back view of a prosthesis according to various embodiments;
• FIG. 5 is a perspective top view of an alignment instrument according to various embodiments;
• FIG. 6A is a perspective front view of a sizing instrument according to various embodiments;
• FIG. 6B is a top plan view of an AP sizer according to various embodiments;
• FIG. 6C is a perspective view of an AP sizer associated with a stylus and an alignment tool;
• FIG. 7 is an environmental view of a portion of an anatomy and a guiding instrument;
• FIG. 8 is an environmental view of an alignment instrument of various embodiments;
• FIG. 9 is an environmental view of a sizing instrument and a section instrument according to various embodiments;
• FIG. 10 is an environmental view of a guide block and a saw blade according to various embodiments;
• FIG. 11A is an environmental view of an alignment instrument according to various embodiments;
• FIG. 11B is an environmental view of an alignment instrument in a knee while in extension;
• FIG. 12 is an environmental view of a guide instrument relative to an anatomy;
• FIG. 13ais an environmental view of a resection guide and a resection instrument relative to an anatomy. According to various embodiments;
• FIG. 13bis an environmental view of a resection instrument relative to an anatomy according to various embodiments;
• FIG. 14 is an environmental view of a resection instrument relative to a portion of the anatomy according to various embodiments;
• FIG. 15 is an environmental view of a resection instrument and resection guide relative to an anatomy according to various embodiments;
• FIG. 16 is an environmental view of a prosthesis positioned relative to a selected portion of an anatomy; and
• FIG. 17 is a prosthesis according to various embodiments.
DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS
• The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate like or corresponding parts and features.
• With reference toFIG. 1, a milling apparatus orsystem10, can include a spigot ormill guide portion12, amill portion14, and a drill motor ordriver16. The drill motor ordriver16 can be any appropriate driver such as pneumatic, electric, air powered, manual powered, or the like. Thedrill motor16 can be any commonly used drill motor for a surgical procedure that is able to be sterilized, re-used, or single use. Themill portion14 can be any appropriate mill, such as the mill used with the Oxford® Unicompartmental Knee™ provided by Biomet, Inc. of Warsaw, Ind. Themill14 can be provided to interconnect with thedrill motor16 in any appropriate manner such as with a chuck, a quick connect, or the like. Themill14 generally provides for milling a selected portion of the anatomy, such as a distal portion of the femur, described further herein. Nevertheless, themill14 usually can be formed to provide a selected mill surface, such as a substantially convex milled surface on the femur or bone portion milled with themill14. Therefore, themill14 can include a concave milling surface or tooth structure. A plurality of cutting teeth18 can be provided on themill14 to mill or resect a selected bone portion in an appropriate manner. It will be understood, however, that themill14 can be formed in any appropriate manner to achieve a selected result. For example, the mill can be provided to form a flat surface on the distal femur, a concave surface on the distal femur, or any other appropriate shape or cross-section. One skilled in the art will understand that mills can be formed in different and appropriate shapes to provide a shaped milled surface.
• Also, thespigot12 can include various portions to interconnect with selected portions of the anatomy. For example, aninsertion end20 can be inserted into a selected portion of the anatomy, such as a distal portion of the femur, a stop area ormember22 can ensure that a selectedguide portion24 extends from the selected bony portion, such as the femur. Also a plurality ofspigots12 can be provided, each having a different length distal end. The different lengths can assist in selections on amount of bone to resect.
• The millingassembly10 can be provided in any appropriate manner for a selected procedure. It will be understood that the millingassembly10 can be provided with each and every piece, also, various pieces can be reusable, or single use. Further, themill14 can be provided in a plurality of sizes depending upon a selected procedure, patient, or the like. Further, theguide12 can be provided in various different sizes, lengths, diameters, etc., for different procedures or different patients.
• With reference toFIG. 2, a guiding block or cuttingblock30 is illustrated. Theguide block30 can be any appropriate guide block such as the guide block disclosed in U.S. patent application Ser. No. 11/337,861, filed on Jan. 23, 2006, commonly assigned, and incorporated herein by reference. Briefly, theguide block assembly30 can include a bone engagement portion, such as afirst pin32 and asecond pin34, arail36 and a cuttingguide block38.
• The cuttingblock assembly30 can be interconnected with any appropriate bone apportion, such as a distal portion of a femur. When interconnected with the distal portion of a femur, the cuttingguide block38 can be used to make various cuts. For example, the cuttingguide block38 can include afirst guide slot40 to form an anterior cut on a femur. The cuttingguide block38 can also include a second guide slot orsurface42 to form a posterior cut and theguide lock38 can include athird guide slot44 to form an anterior chamfer cut. The various guide slots40-44 can be used to resect a bone, such as the femur, to interconnect with a selected portion. It will be understood, however, that theguide block38 can also include various other guide passages or slots, such as to form a posterior chamfer cut, medial or lateral cuts, or any appropriate portion.
• Further, theguide block38 can be formed to move relative to thetract36 as is taught in the previously incorporated application. The cuttingblock38 can define anarticulation portion46 which articulates with a portion of therail36 to allow thecutting block38 to slide relative to therail36. The cuttingblock38 can then be formed at any appropriate size, such as about three centimeters to about six centimeters in width, or any other appropriate size. The cuttingblock assembly30 can be interconnected with a bone portion in any appropriate manner, such as those described further herein. Also, the various slots40-44, can be used to guide instruments, such as a saw blade, relative to a portion to which theguide assembly30 is attached.
• With reference toFIGS. 3A to 3D, aprosthesis60 is illustrated. Theprosthesis60 can be any appropriate prosthesis, such as a distal femoral prosthesis. Theprosthesis60 is exemplary illustrated as a distal femoral prosthesis, but the various features and portions thereof can be incorporated on any selected implant assemblies. Also, theprosthesis60 is exemplary a cruciate retaining prosthesis, but it can also be a posterior stabilized, constrated, or any combination thereof.
• Theprosthesis60 can include various portions to replace or mimic the distal femoral portion. For example, theprosthesis60 can include afirst condyle portion62 and asecond condyle portion64. Thecondyle portions62,64 can replace the medial and lateral condyles of a distal portion of a femur. It will be understood that thecondyle62,64 can be any appropriate condyle portion such as the medial or lateral condyle portion, and is exemplary listed here only.
• Thecondyle portions62,64 can interconnect and be formed as a single piece with apatellar tract portion66. Thepatellar tract portion66 can allow a place for articulation of a patella, either natural or prosthetic patella, once theprosthesis60 is implanted onto the distal femoral portion. Thecondyle62,64 andpatellar tract66 can generally define an exterior portion of theprosthesis60. The exterior portion of the prosthesis can be substantially curved, either continuously or discontinuously, to replace a distal femoral portion. Further, it will be understood that theprosthesis60 can define an opening orpassage68 between the twocondyles62,64. Alternatively, according to various embodiments, theprosthesis60 can define a substantially solid portion between thecondyle62,64 for various reasons, such as a particular patient, a particular application, or the like. Also theprosthesis60 can be formed from many pieces and be interconnected prior to implantation, during implantation, or at any appropriate time.
• Theprosthesis60 can further define a bone contacting orinterior surface70. Theinterior surface70 can be substantially smooth, can be porous, or any combination thereof. It will be understood that a porous portion, such as a porous coating, can be applied to theinterior surface70 of theprosthesis60 to allow for bone ingrowth, adhesive adhesion, or the like. Regardless, theinterior surface70 can include various portions.
• A first portion of the interior70 can be a substantiallyanterior surface72. The anterior surface can be substantially flat and formed an angle relative to asecond portion74. Theanterior surface72 can be provided to contact an anterior portion of a distal femur, as illustrated herein. Thesecond surface74 can be a portion that is operable to contact an anterior chamfer portion, such as an anterior chamfer cut, formed on a distal femur. Thefirst surface72 and thesecond surface74 can be formed at any appropriate angle relative to one another, and can depend upon an anatomy of the patient, a characteristic of the prosthesis, or any appropriate reason. A third surface can be a substantiallyposterior surface76aand76B. The posterior surfaces76a,76b, can be provided as two surfaces, as illustrated here when thespace68 is formed or it can be a substantially single surface that is continuous along the width of theprosthesis60. Nevertheless, the posterior surfaces76a,76bcan be formed to contact a posterior portion of the femur as illustrated herein.
• The interior surface of a substantial portion of the condyle,62,64 can be substantially curved. A firstcurved surface78 can be formed opposite thefirst condyle62 and a secondcurved surface80 can be formed opposite thesecond condyle64. The curved surfaces78,80 can be curved relative to the other surfaces of theinterior portion70 of theprosthesis60. Thecurved surface80 is exemplary illustrated inFIGS. 3C and 3D, butcurved surface78 can be similarly illustrated.
• The firstcurved surface78 can include a substantially anterior to posterior curvature that includes afirst radius78ithat can be used to form anarc78i′. Asecond radius78iican define a second medial tolateral arc78ii′. The two arcs78i′ and78ii′ can define two curved surfaces or two radii that define thecurved surface78. The curved surface of78 can contact a selected portion of the anatomy, such as a prepared distal femur, as discussed further herein.
• The secondcurved surface80 can include similar portions. For example, afirst radius80ican define anarc80i′ similar to thearc78i′. Also, asecond radius80iican define asecond arc80ii′ that is similar to thesecond arc78ii′. As discussed above, thecurved surface80 is exemplary illustrated in detail inFIGS. 3C and 3D butcurved surface78 can be understood to be similar tocurved surface80.
• The curved surfaces78,80 can be formed on theprosthesis60 in any appropriate manner, such as by milling, casting, or any other appropriate formation procedure. Further, the various other surfaces defined by theinterior70 of theprosthesis60 can be formed in any appropriate manner such as milling or casting.
• As discussed above, theprosthesis60 can be interconnected with a portion of the anatomy, such as the distal portion of the femur, in any appropriate manner. Further, theprosthesis60 can define afirst projection84 and asecond projection86. Theprojections84,86 can project into a selected portion of the anatomy, such as a distal portion of the femur, to assist in interconnecting theprosthesis60 with the anatomy. Theprojections84,86 can be formed in any appropriate manner and can be formed as a single piece with theprosthesis60, formed separately and integrated therewith, or provided in any appropriate manner. Theprojections84,86 can also include a substantially smooth or porous surface, or combinations thereof. As discussed above, a porous surface can assist with bone ingrowth, adhesive adhesion, or any other appropriate purpose.
• With reference toFIG. 4, aprosthesis90, according to various embodiments, is illustrated. Theprosthesis90 can include portions substantially similar to theprosthesis60. Therefore theprosthesis90 can include an exterior surface that defines a first condyle andsecond condyles92,94 substantially similar to the first andsecond condyles62,64 of theprosthesis60. Also theprosthesis90 can define apatellar tract96 similar to thepatellar tract66 in theprosthesis60. An internal surface of theprosthesis90 can also include a first substantiallyplanar section98 and a second substantiallyplanar section100. Athird section102aand102bcan include a posterior portion similar to theposterior portions76a,76bof theprosthesis60.
• Theinterior surface97 can include portions that are dissimilar on an interior portion opposite thecondyles92,94. For example, the interior surface opposite thefirst condyle92 can includes substantially planar sections, such as a distalplanar section104 and a posterior chamferplanar section106. The distalinternal section104 can be placed at an angle relative to theposterior chamfer section106 in a manner substantially similar to prosthesis generally available, just as the Ascent® prosthesis provided by Biomet, Inc. of Warsaw, Ind.
• The interior surface opposite thesecond condyle94, however, can be curved similar to the curvature of the interior portions of theprosthesis60. Therefore, the interior surface opposite thesecond condyle94 can include afirst radius108ithat defines anarc108i′ in a generally medial to lateral direction. Also, as discussed above, the curved surface of the interior of thecondyle94 can be similar to thecurved surface80 illustrated inFIGS. 3C and 3D. A second arc108iican define a second radius108ii′ in a generally anterior to posterior direction. Therefore, the interior surface opposite thesecond condyle94 can be curved substantially similar to thecurvature78,80 of theprosthesis60. Further, a projection or post110 can extend from the second surface opposite thesecond condyle94 and can also optionally be provided to extend from the distalplanar portion104.
• It will be understood that theprosthesis90, according to various embodiments, can include an interior surface that includes both a curved portion and a substantially planar portion. Theprosthesis90 need not include a substantially symmetrical interior surfaces. The interior of theprosthesis90 can be based upon the process of forming the distal femoral portion or any appropriate bony portion. Theprosthesis90 can be provided for a formation of a distal femur that can have a substantially curved facing portion for one condyle and a planar portion for a second condyle.
• Distal femoral prostheses, such as theprosthesis60 and theprosthesis90 can be implanted according to any appropriate method and with the assistance of any appropriate instruments. For example, the bone portion, such as a distal portion of the femur, can be resected or prepared according to a plurality of steps, such as milling. To ensure that the several steps are appropriately aligned for positioning the prosthesis relative to the femur, various instruments can be used to assist the procedures. It will be understood that the instruments and method described herein are merely exemplary.
• With reference toFIG. 5, analignment tool120 is illustrated. Thealignment tool120 can be any appropriate alignment tool, including that illustrated inFIG. 5 and described in currently pending U.S. patent application Ser. No. 11/______ (attorney reference 5490-000473), concurrently filed and incorporated herein by reference. Thealignment tool120 can be used to ensure that appropriate resections cut in one bone are aligned relative to one another and/or aligned to portions of adjacent bones.
• Briefly, thealignment tool120 can include agraspable portion122 andextension arm124 and a spacer portion oralignment portion126. Thealignment portion126 can include aconnection mechanism128 to interconnect with a connection mechanism of aspacer member130. Thespacer member130 can include a plurality of spacer members of different heights, or other appropriate dimensions, to be interconnected with thealignment portion126. Thespacer members130 can be interconnected, such as with a snap fit, to theconnection mechanism128 of thealignment portion126. As discussed herein, thealignment portion126 can include thespacers130 to assist in assuring appropriate alignment or spacing between various portions of the bone.
• Theextension arm124 can include a passage or define apassage132 through which an alignment rod can pass. As discussed herein, an alignment rod can be used to ensure appropriate alignment of the various bones relative to one another when various resections are aligned relative to one another with thealignment portion126.
• With reference toFIG. 6A, asizer140 is illustrated. Thesizer140 can be used to select or obtain an appropriate size for an implant member to be positioned relative to a selected bone. Thesizer140 can be an anterior posterior (AP) sizer. This can ensure that the anterior to posterior distance of the second bone, such as the femur, is appropriate.
• TheAP sizer140 can include two general portions, including afirst guide portion142 and asecond base portion144. Thebase portion144 can include afirst side146 that includes a selected dimension that is larger than asecond side148. The first side relative to the second side can allow it to rest upon a selected instrument, such as thealignment guide120 to reference relative to thealignment guide120. From a lower orbottom surface150 of the second side to alower bottom surface152 of the first side can be any appropriate dimension such as adimension154. Thedimension154 can be any appropriate dimension such as about 2 mm to about 10 mm. Regardless, thedimension154 can generally allow thesizer140 to rest upon theguide120 regardless of the differential between thevarious spacer members130 are interconnected with thealignment surface126. In this way, the referencing for theguide portion142 can be from the lower side of thealignment instrument120.
• Thebase portion144 can interconnect with theguide portion142 in a rotational manner so that the taller side can contact the lowest portion of thealignment tray126. Thebase portion144 can define abore156 which can rotationally receive aspindle158 of theguide portion142. This can allow theguide portion142 to rotate relative to thebase portion144. It will be understood that any appropriate mechanism will be used or provided to interconnect or selectively lock thebase portion144 relative to theguide portion142. For example, a quick release mechanism can be provided which can include a member biased in a selected direction by a spring that can selectively engage and disengage to interconnect thebase portion144 relative to a selected orientation of theguide portion142.
• Theguide portion142 can include any appropriate portions. For example, theguide portion142 can include or define afirst passage162 and asecond guide passage164. Theguide passages162,164 can be used to guide a selected instrument, such as a drill point, relative to a selected portion, such as a portion of a bone. Theguide passages162,164 can be any appropriate size or dimension relative to one another to achieve a selected result.
• Theguide portion142 can also include a scale marking166 to allow for determining of a selected dimension. As is generally understood in the art, astylus member168 can be used to contact a selected portion, such as a portion of a bone, to move anindicator170 relative to thescale166. This can assist in the selection of an apparatus, such as a selected size of a prosthesis for implantation relative to the bone to which the sizingmember140 is used.
• The various instruments and prosthesis discussed above can be used according to any appropriate method of implantation or if any appropriate instrument set. The exemplary method discussed herein is only to provide an exemplary method of using and implanting the various prostheses and tools.
• According to various embodiments, theAP sizer140 can be provided to include various portions. With reference toFIGS. 6B and 6C, anAP sizer140′ is illustrated according to various embodiments. Thesizer140′ can be substantially similar to thesizer140, illustrated inFIG. 6A, and identical portions or substantially similar portions thereto will not be described in detail here. Briefly, thesizer140′ can include thefirst guide portion142′ and thebase portion144′ substantially similar to thefirst guide portion142 andbase portion144 discussed above. For example, the base144′ can include a first side that is longer or larger than a second side and thefirst alignment portion142′ can include ascale166′ that can be used in the sizing procedure. Similarly, thestylus168 can be provided with thesizer140′ to assist in performing a procedure.
• As discussed above, theguide portion142 can include guidepassages162,164 that can be used to form holes in a bone, such as a distal portion of the femur. Thesizer140′ can includealignment members162′ and164′ that can be substantially similar to theguide passages162,164 but can be adjustable. Theguide passages162′ and164′ can include abone contacting portion162a′ and164a′, respectively, and a non-bone contacting ordistal portion162b′ and164b′.
• Thebone contacting portions162a′ and164a′ can contact the condyles of the femur and assist in aligning thesizer140′ relative to the femur. As discussed further herein, the procedure can include determining an extension gap between the tibia and the femur. If there is a difference between the medial and lateral sides of the femur relative to the tibia in the extension gap, then theguide members162′ and164′ can be appropriately set. For example, with particular reference toFIG. 6B, and assuming that the sizer is positioned relative to a left leg, themedial guide member164′ can be positioned a distance M away from thefirst alignment portion142′ further than thelateral guide member162′. Therefore, the medial extension gap is greater than the lateral extension gap. Thealignment member164′ can be moved so that thebone engaging portion164′aengages the bone of the femur in an appropriate manner. This can help ensure that the holes that are being drilled with the alignment or guidebodies162′,164′ are substantially parallel to the mechanical axis of the femur and based upon the difference in the extension gaps.
• Thealignment members162′,164′ can be moved in any appropriate manner. For example, thealignment members162′,164′ can include external threads while the body portion of thefirst alignment member142′ includes internal threads to allow for themembers162′,164′ to be rotated to achieve an appropriate movement of theguide member162′,164′. Further, a ratcheting system, a lock system, aspacer clip165′, or the like, can be positioned to assist in holding the selectedguide member162′,164′ in an appropriate position relative to thefirst guide body142′.
• Further, theguide members162′,164′ can include pin holes167′ or a plurality thereof, to assist in holding theguide members162′,164′, relative to the condyles of the femur. It will be understood that this can help assist the maintaining of the position of thesizer140′ relative to the femur, and to the positioning of theguide members162′,164′ relative to the femur. It will be understood, as illustrated particularly inFIG. 6C, that thesizer140′ can be used with thealignment member120 as discussed further herein. Therefore, it will be understood that the sizers,140,140′ can be provided according to various embodiments to achieve a selected result. Further, thesizer140′ can be used in any appropriate manner, such as that discussed relative and with thesizer140.
• With reference toFIG. 7, a portion of an anatomy, such as aknee portion200 is illustrated. The knee portion can generally include afemur202 and atibia204, adistal portion206 of the femur can include afirst condyle208 and asecond condyle210. The first andsecond condyles208,210 can be any appropriate condyles, such as a medial and lateral condyle. As illustrated here, thefirst condyle208 is a medial condyle while thesecond condyle210 is a lateral condyle. Although the following exemplary discussion can relate to a medial lateral condyle, it will be understood that the various instruments and prostheses can be used for any appropriate procedure and the first and second condyles can also be a lateral and medial condyle respectively.
• Thetibia204 can include a proximal portion of thetibia212 that can be resected according to any appropriate method. Also, theknee200 is generally surrounded bysoft tissue214. The soft tissue can include adipose tissue, muscle, connective tissue, or any appropriate tissue. Thesoft tissue214 can be entered by forming anincision216 in the soft tissue. Theincision216 in thesoft tissue214 can allow access to the bones, such as thefemur202 and thetibia204 to perform a procedure relative thereto.
• Thetibia204 can be resected in any appropriate manner such as milling or cutting. For example, anexternal rod220 can be interconnected with aguide member222 to perform a resection of theproximal tibia212. Theguide member222 can be interconnected with therod220 in any appropriate manner. Further, therod220 can be interconnected with a selected instrument or a portion of the anatomy, such as with an ankle clamp. It will be understood that therod220 and theguide220 can be used according to any appropriate method, such as those generally known in the art.
• With reference toFIG. 8, once thetibia204 has been resected, at least in the first instance, thealignment instruments120 can be positioned between thetibia204 and thefemur202 when theknee200 is in extension. Thealignment tool120 can be positioned between the femur and thetibia202,204 to ensure an appropriate distance or soft tissue tension between the two bones. It will be understood that thespacer members130 can be positioned relative to thealignment tray126 to ensure an appropriate contact between thefemur202 and thealignment tool120 when it is positioned between the two bones. It will be understood that if thealignment tray126 cannot be positioned between thetibia204 and thefemur202, a further amount of thetibia204 can be resected. Nevertheless, thespacers130 can ensure, after an initial resection of thetibia204, that thealignment tool120 can contact both of the condyles of thefemur202 and the resected portion of thetibia204.
• With thealignment tool120 positioned between thefemur202 and thetibia204, a varus/valgus alignment rod230 can be inserted through thepassage132 defined by thealignment tool120. If the varus/valgus alignment rod230 aligns or passes through afemoral head232, generally formed at an proximal end of thefemur202, an appropriate varus/valgus angle has been achieved. It will be understood, however, that if the varus/valgus alignment rod230 does not intersect or become aligned with thefemoral head232, that various soft tissue releases can be performed to achieve the appropriate alignment of thefemur202 and thetibia204. It will be understood that soft tissue releases can be performed in any manner, such as those generally understood in the art.
• Once the appropriate varus/valgus alignment has been achieved, theknee200 can be moved into flexion, wherein the tibia is positioned at an angle relative to thefemur202. With the knee in flexion, as illustrated inFIG. 9, thealignment tool120 can be re-positioned relative to thefemur202 and thetibia204. With the knee in flexion and thealignment tool120 positioned on the resected proximal portion of thetibia204, thealignment tool120, in particular thealignment surface126, is operable to contact a posterior portion of thefirst condyle208pand the posterior portion of thesecond condyle210p. It will be understood that if thealignment surface126 cannot fit between theposterior condyles208p210pin a resected surface of thetibia204, that further resection of thetibia204 can be performed. Further, as discussed above, various of the spacer blocks130 can be interconnected with thealignment tray126 to ensure a proper fit of thealignment tool120 relative to thefemur202 and thetibia204. Any appropriate height or dimension of the spacer blocks130 can be achieved by interconnecting a selected one of the spacer blocks with thealignment tray126. Therefore, a greater or lesser alignment block can be used to achieve an appropriate contact. Generally, a user can select the pressure or the firmness of contact between the various bone portions and thealignment tray126 or the selectedspacers130.
• Once the appropriate contact has been achieved between thealignment instrument120 and thefemur202 and thetibia204, thesizer140 can be placed relative to thealignment instrument120. It will be understood that thesizer140 can be positioned relative to thealignment instrument120 in any appropriate manner. For example, a connecting mechanism, including a lock, a magnet, or the like, can assist in holding the sizinginstrument140 relative to thealignment instrument120. Further, thebase144 of the sizinginstrument140 can contact the various portions of thealignment tray126 and anyspacers130 that may be present. Nevertheless, the taller orlarger side146 of the base144 contacts the lowest side of thealignment instrument120 so that references can always be taken off the lowest side. It will be understood, however, that reference can be taken relative to any appropriate portion of thealignment tool126 and that referencing from the lower side of thealignment tool120 is merely exemplary.
• Once the sizinginstrument140 has contacted thealignment tray126, thestylus168 can contact the selected portion of thefemur202, such as a proximal anterior surface thereof. Thestylus168 can contact the anterior surface of thefemur202 so that themarker170 is positioned relative to thescale166 to assist in selecting appropriate prosthesis size. The appropriate size can be determined based upon thescale166 and can be any appropriate size. It will be understood that theprostheses60,90 can be provided in a plurality of sizes and can be provided in a kit, including a plurality of sizes, to be selected based upon thesizer140. Nevertheless, it will be understood that any appropriate mechanism or method can be used to select the appropriate size of the prosthesis, such as user experience, other measuring or sizing tools.
• Further, the guide holes162,164 can be used to assist in formingbores240 within thecondyles208,210 of thefemur202. Any appropriate tool, such as adrill point230 interconnected with adrill motor232 can be used to form the bores in thefemur202. Thedrill point230 can be guided through the guide bores162,164 to form thebores240 within thefemur202 and appropriate positions relative to theposterior surfaces208p,210pofcondyles208,210. Once the bores are formed in thefemur202, thealignment apparatus120 and thesizer apparatus140 can be removed from theknee200.
• Once thealignment120 and thesizer instrument140 are removed, the three-in-onecutting block30 can be positioned relative to thefemur202. The holding pegs32 can be positioned within the formed bores240 in thefemur202. A resection tool, such asreciprocating saw blade242 can be powered by asaw motor244 to form a selected resection of thecondyles208,210. For example, theguide slot42 can be used to form a posterior resection of thecondyles208,210. The resection can be substantially parallel to theguide slot42 and formed as a substantially flat surface on the posterior portion of thefemur202 relative to thecondyles208,210. It will be understood, however, that any appropriate resected surface can be formed on thefemur202. Further, it will be understood that theguide portion38 of theguide assembly30 can move relative to therail36 according to any appropriate mechanism. Various mechanisms and guide portions are described in currently pending and commonly assigned U.S. patent application Ser. No. 11/337,861 (Attorney Docket No. 5490-000306/CPD), filed on Jan. 23, 2006, and incorporated herein by reference. Once the posterior cut is formed with theguide assembly30, thealignment tool120 can be used to determine a flexion gap of theknee200.
• With reference toFIG. 11A, once the posterior resection of thefemur202 is completed, a cut spacer ordistal cut spacer250 can be interconnected with thealignment tray126 in any appropriate manner. Generally, thecut spacer250 can be interconnected with thealignment tray126 on a bottom portion thereof to allow for the connection of thespacers130 to a top portion of thetray126 if required. Nevertheless, thecut spacer250 is connected with thealignment tray126 to mimic the amount of bone or portion resected due to the resection of the posterior portion of thefemur202.
• The cuttingblock30 is used to resect a selected amount of the posterior portion of thefemur202. Therefore, thecut spacer250 can mimic the amount of bone removed and ensure that an appropriate gap is formed between thefemur202 and thetibia204. Thevarious spacers130 can also be added to thealignment tray126 if the selected contact between thefemur202 and thealignment tray126 is not achieved. In any case, the spacing between thetibia204 and thefemur202 can be determined with thealignment tool120. Further, the amount can be noted for use later on. This spacing is generally obtained while thefemur202 is in flexion relative to thetibia204, as opposed to the extension gap obtained earlier prior to the resection of the femur and immediately after the resection of thetibia204.
• If any of thespacers130 were required prior to the posterior resection of thefemur202, the smallest spacer size would be interconnected with thealignment tray126 on both sides relative to bothcondyles208,210 during the flexion gap measurement. If no spacer were used on one side relative to one of thecondyles208,210, then no spaces would be used relative to thealignment tray126 when determining the flexion gap. It will be understood that the flexion gap can generally be determined once the posterior resection of thecondyles208p,210phas occurred.
• Also, in addition to the earlier extension gap determination, the extension gap can be re-determined as illustrated inFIG. 11B. With theknee200 in extension, thealignment tray126, without thecut spacer250, can be reinserted between the femur and the tibia where theknee200 is in extension. Thespacers130 can be interconnected with thealignment tray126, if necessary, to provide a tight fit between thetibia204 and thefemur202 with thealignment tool120. The gap in extension can thus be determined.
• The extension gap can then be subtracted from the flexion gap to determine a length for thespigot12. Thespigot12 can include a length or guide portion that is substantially equal to the difference between the extension gap and the flexion gap to ensure that only an appropriate amount of thefemur202 is resected. It will be understood that thespigot12 can be provided in appropriate sizes, such as in about 2 mm differences, to ensure that the amount resected with themill14 is an appropriate amount guided by thespigot12. Nevertheless, once the difference in gap is determined, the appropriate spigot can be determined. Also, it will be understood, that the difference between thecondyles208,210 can be the same or not be the same; therefore, thespigot12 used for each of thecondyles208,210 can be different.
• With reference toFIG. 12, once the appropriate spigots are determined, they can be inserted into thebores240 defined in thecondyles208,210. Any appropriate instrument or tool, such as thehammer270, can be used to insert thespigots12 into thecondyles208,210. It will be understood that different size spigots can be used, such as afirst spigot12aand a second spigot12b. Therefore, thefemur202 can be resected in the appropriate manner with themill14 illustrated inFIG. 13, to achieve a selected amount of resection of thefemur202.
• Further, it will be understood, that themill14 can provide a substantially spherical surface on thecondyles208,210. The spherical or curved surface on thecondyles208,210 can mate with any appropriate implant, such as theprosthesis60, or theprosthesis90. Although the resection can be any appropriate shape.
• In addition to providing thespigot12a,12bto guide themill14 relative to each of thecondyles208,210, a second mechanism can, alternatively or in addition, be used to resect a second or adjacent condyle. For example, with reference toFIG. 14, aresection guide300 can be positioned relative to thebore240 formed in one of the condyles, such as thecondyle208. Theresection guide300 can include a guide slot to guide asaw blade302 relative to thesecond condyle210. Thesaw blade302 can be powered by any appropriate instrument, such as asaw motor304. Thesaw motor304 can move thesaw302 in a substantially reciprocating or vibrating fashion. Therefore, thesaw blade302 can cut thesecond condyle210 relative to thebore240 formed in thefirst condyle208. Thefirst condyle208 can be first resected with themill14 or thesecond condyle210 can be resected prior to the resection of thefirst condyle208.
• According to various embodiments, thesaw guide300 can be positioned relative to the milledsurface304 of thefirst condyle208 so that thesaw guide300 is positioned at the resected surface or depth of thefirst condyle208. Therefore, thesaw302 can be moved relative to thesecond condyle210 to form a resection that is substantially aligned with theresection304 of thefirst condyle208. This can allow for thefemur202 to be resected in a manner that is appropriate to position a prosthesis, such as theprosthesis90. It will be understood that thecut surface304 formed with themill14 can be curved in a selected manner while the surface of thesecond condyle210 resected with the saw can be substantially flat. Therefore, theprosthesis90 that includes both a flat distal portion and a substantial curved distal portion which can mate with the resected portions of thefemur202 resected with the mill and the saw blade. It will be understood, however, that the femur, including thecondyles208,210 can be resected in any appropriate manner.
• Once the initial resection of the distal portion of thecondyles208,210 is completed, the various guides, such as thespigot12 or thesaw guide300 can be removed. Previous extraneous portions of bone can be removed in any appropriate manner, such as with a Rongeur, an ostephyte chisel, or any other appropriate tool. It is understood by one skilled in the art that the resected surface of thefemur202 can be prepared in any appropriate manner to allow for implantation of a prosthesis, such as theprosthesis60 or theprosthesis90.
• Once the resection guides are removed, thecut spacer250 can be reconnected or connected with thealignment tool120 and positioned between thefemur202 and thetibia204 with theknee200 in extension. This can be done to ensure that an appropriate extension gap is created prior to positioning the implant or prosthesis portions or trial prosthesis portions into theknee200. If the appropriate extension gap has not been achieved, as determined by any appropriate means such as thealignment tool120, additional material from the bone, such as thefemur202, can be resected. This can be repeated until an appropriate amount of thefemur202 has been resected to achieve an appropriate gap.
• Once the appropriate extension gap has been achieved, the resection guide or cuttingblock30 can be reconnected with thefemur202 with use of thebores240 as illustrated inFIG. 15. The cuttingguide30 can be used to form an anterior resection of thefemur202 and an anterior chamfer cut of thefemur202. It will be understood, by one skilled in the art, that these cuts may be typical for resecting thefemur202 to allow for implantation of a selected distal femoral prosthesis. Any appropriate tool can be used to form the resection, such as thesaw blade242 and thesaw motor244. A user, such as a surgeon, can use thesaw242 and sawmotor244 to resect portions of thefemur202 using the cuttingguide30. As discussed above, the cuttingguide30 can move relative to thefemur202 on the rail, as illustrated inFIG. 15.
• Once the final portions of the femur are resected with theguide30, the implant, such as theimplant60 or theimplant90, or any other appropriate prosthesis or implant can be positioned relative to the resected portion of thefemur202 as illustrated inFIG. 16. As discussed above, the prosthesis can include various portions such as smooth surfaces, roughened surfaces, porous coated surfaces, or the like to allow or assist with fixation of theprosthesis60,90 relative to thefemur202. Also, other prosthesis members can be positioned, such as atibial member310 and abearing312. These can be any appropriate portions such as those generally known in the art. Though any prosthesis members may be used, such as more bearing members or no bearing members.
• Therefore, a user, such as a surgeon, can decide to use an adhesive such as bone cement (e.g. polymethylmethylacrylate) or any appropriate material. Alternatively, a user can decide to implant the prosthesis using no adhesive to allow for bone ingrowth over a selected period of time. Further, the various prostheses can first be trials positioned relative to the resected portions of thefemur202 and thetibia204. The trials can ensure an appropriate fit of the prosthesis relative to the resected portions of the femur and the tibia. The trialing can also determine whether additional resection may be necessary to achieve an appropriate fit. Nevertheless, the use of the various instruments, such as thesizer140, can assist in ensuring the appropriate size selection for the prosthesis. As discussed above, the kits or a kit can include a plurality of the prosthesis members of different sizes, including heights, thicknesses, widths, and the like to achieve an appropriate fit with the femur of the patient.
• Further, one skilled in the art will understand that the use of the various prosthesis, instruments, and the like, can allow for theincision216 can be about 2 cm to about 10 cm, such as about 4 cm to about 8 cm. Theincision216 can be formed by a user according to any appropriate purpose, such as achieving appropriate visualization of the internal anatomy, including thefemur202 and thetibia204 or minimizing trauma to a patient. Nevertheless, themill14 can be passed and operated through substantially small incision, such as that generally known in the art such as the procedure and use for the Oxford® Unicompartmental Knee Implant™ instrumentation provided by Biomet, Inc. of Warsaw, Ind. The procedure here, however, can allow for positioning to complete distal femoral prosthesis. This can generally be assisted by resecting only a selected one of thecondyles208,210 at a time. The instrumentation allows for guiding a selected resection instrument relative to a single one of thecondyles208,210, if selected. Nevertheless, the resections of both of thecondyles208,210 can be substantially aligned or achieved in an appropriate manner by allowing the selected resections to be formed relative to one another in a substantially aligned manner. Therefore, thecondyles208,210 can be resected separately and still be substantially aligned for use of implantation of a selected prosthesis.
• As discussed above, various prosthesis members can be provided according to various embodiments. For example, with reference toFIG. 17, a posterior stabilized (PS) knee implant or a substantially constrained or hinged knee prosthesis can be provided. Although a PS stabilized knee or a constrained knee can provide for greater stability in a knee prosthesis, the prostheses can include various features as discussed above.
• With reference toFIG. 17, a distalfemoral prosthesis350 is illustrated. Theprosthesis350 can include the portions that are substantially similar to theprosthesis60 and similar numerals are used to reference the similar portions. For example, theprosthesis350 can include a first curvedinterior surface78 and a second curvedinterior surface80. The curvedinterior surfaces78,80 can be substantially similar to the curved surfaces discussed above in relation to theprosthesis60 including the various arcs, radii, and curvatures as illustrated inFIGS. 3A-3D. Further, anexterior surface66, such as a patella track, can be provided.
• Although the interior portion of theprosthesis350 can include various planar portions, such as an anteriorplanar portion72, an anterior chamferplanar portion74, and posteriorplanar portions76a,76b, in conjunction with thecurved surfaces78,80; it can also include an internal structure, such as a stabilizingstructure352. The stabilizingstructure352 can include any appropriate posterior stabilizing structure, such as those generally known in the art including those provided in the Maxim® knee prosthesis provided by Biomet, Inc. of Warsaw, Ind. The stabilizing structure can be a posterior stabilizingbox352 that can cooperate with aposterior stabilizing post354 of anappropriate tibial component356. Thetibial component356 can include atibial tray358 that is able to engage a selected anatomical portion, such as thetibia204. A stem orboss360 can be provided to engage thetibia204 in a selected manner, such as to reduce rotation of thetibial component356 after implantation. It will be understood that various methods and apparatuses can be used to implant, fix, etc., thetibial component356 relative to thetibia204.
• Abearing component362 can incorporate theposterior stabilizing post354 or theposterior stabilizing post354 can be provided separate from thebearing component362 as a single member with thetibial tray358, or in any appropriate combination. Nevertheless, one skilled in the art will understand that theposterior stabilizing post354 can interconnect with the stabilizingbox352, also known as anintercondylar box352, to assist in stabilizing thefemur202 relative to thetibia204 after implantation of theprosthesis350.
• Further, theprosthesis350 can include various components, such as an intramedullary post or stem364 to assist in interconnection or fixation of the prosthesis relative to thefemur202. It will be understood that any other appropriate portions, such as theprojections84,86, can also be provided to assist in fixation of theprosthesis350 relative to thefemur202. It is further understood that theintramedullary stem364 is merely exemplary and can be provided or not provided in various fashions, such as a modular stem.
• In addition, theintercondylar box352, or other appropriate structure, can provide apassage370 that can interconnect with apin371 or other axle of a hingedstem372 of atibial component374. It will be understood that either of thetibial component356 or thetibial component374 can be provided in various combinations with theprosthesis350 according to the decision by a user, the physical aspects of the patient, or in any selected combination to achieve a selected result. It will be understood that theprosthesis350 can include any appropriate portions to allow for interconnection with thetibial prosthesis356 or thetibial prosthesis374.
• Thetibial prosthesis374, however, can also generally include a bearingportion376 that can be provided relative to atibial tray378 that can include a boss or astem380 that can be interconnected with thetibia204. Again, it is understood by one skilled in the art that the method and implantation process of thetibial stem374 such as the OSS™ Orthopaedic Salvage System knee provided by Biomet, Inc. of Warsaw, Ind.
• Therefore, it will be understood that theprosthesis350, that can include one or two curved surfaces to contact a selected portion of the anatomy, such as the femur. While theprostheses60,90, can generally understood to be cruciate retaining prostheses, other types such as a posterior stabilized or constrained knee prosthesis, such as theprosthesis350, can be provided to interconnect with thefemur202. These various types of knee prostheses can also include fixed or floating bearing members or no bearing members. Also, the prostheses can be primary or revision prostheses. One skilled in the art will understand that the selection of the appropriate prosthesis can be made by a user for implantation relative to a patient. Nevertheless, the various curved or flat surfaces can be provided in any appropriate combination for any appropriate prosthesis type for implantation into an anatomy.

Claims (6)

1. A system for positioning a prosthesis relative to a selected portion of an anatomy, comprising:

a mill operable to mill the anatomy;

a first mill guide operable to guide the mill relative to the anatomy;

a second mill guide operable to guide the mill relative to the anatomy;

a mill guide placement system operable to assist in a positioning of the first mill guide and the second mill guide; and

an alignment instrument operable to align at least one of the first mill guide, the second mill guide, the mill guide placement system, or combinations thereof relative to the anatomy.

2. The system ofclaim 1 wherein the mill guide placement system is operable to assist in positioning the first mill guide relative to the second mill guide relative to the anatomy.

3. The system ofclaim 2, further comprising:

a bore forming apparatus;

wherein the bore forming apparatus is operable to form a bore guided by the mill guide placement system and the first mill guide placement system and the first mill guide or the second mill guide are operable to engage the bores to be positioned relative to the anatomy.

4. The system ofclaim 1, wherein the mill guide placement system includes a medial alignment member and a lateral alignment member positionable relative to a medial portion of a bone and at a lateral portion of the anatomy.

5. The system ofclaim 4, wherein the medial alignment member is moveable relative to the lateral alignment member to allow the medial and the lateral alignment members to contact the medial-lateral portions of the anatomy at a selected point.

6. The system ofclaim 5, wherein the medial and lateral guide members are operable to be positioned relative to the medial-lateral portions of the anatomy to allow the mill guide to be positioned substantially parallel to a mechanical axis of the anatomy.

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