Abstract:
Instruments for use in resecting, reshaping, and preparing the end of a bone to receive an implant. The instruments may be equipped with indicator devices in the form of light-emitting devices to project an indicator onto the bone. Examples of such instruments may be a cut guide equipped with a built-in cut plane indicator device and a cut plane indicator device for use with existing cut guides. The cut plane indicator device may provide a visual indication or cue on a surface of the bone indicating where the cut plane of the cut guide will intersect the bone.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit under Title 35, U.S.C. §119(e) of U.S. Provisional Patent Application Ser. No. 60/783,244, entitled CUT PLANE INDICATOR DEVICE FOR USE WITH A CUT GUIDE, filed Mar. 17, 2006, the disclosure of which is hereby expressly incorporated herein by reference. 
    
    
     BACKGROUND 
     The present disclosure relates to guide instruments for use in preparing the surface of a bone to receive an implant and, more particularly, to a light-emitting device for indicating a location on the bone surface. 
     Orthopaedic procedures for the replacement of all, or a portion of, a patient&#39;s joint typically require resecting and/or reshaping of the ends of the bones of the joint. For instance, total knee replacement procedures typically involve resecting the distal end of the femur and the proximal end of the tibia prior to implanting the prosthetic components. 
     Guide instruments, such as cut guides, for example, have been developed to guide a resection instrument, such as a saw, for example, in making cuts on the femur and the tibia. Conventional cut guides are often in the form of blocks having slots therein for receiving and guiding the saw. In use, the block is positioned against the bone with the help of positioning and alignment equipment. Once the cut block is properly positioned, the resection instrument is inserted through the cut slot of the block and into the bone. 
     SUMMARY 
     The present disclosure provides instruments for use in resecting, reshaping, and preparing the end of a bone to receive an implant. The instruments may be equipped with indicator devices in the form of light-emitting devices to project an indicator onto the bone. Examples of such instruments may be a cut guide equipped with a built-in cut plane indicator device and a cut plane indicator device for use with existing cut guides. The cut plane indicator device may provide a visual indication or cue on a surface of the bone indicating where the cut plane of the cut guide will intersect the bone. 
     In one form, the present disclosure provides a guidance system for guiding a surgical procedure performed on an anatomical structure, the guidance system including a surgical guide instrument including at least one guide surface, the at least one guide surface extending along a guide direction; and a light-emitting device securable to the guide instrument in a secured position such that an output of the light-emitting device is projected along the guide direction. 
     In another form thereof, the present disclosure provides a guidance system for guiding a surgical procedure performed on an anatomical structure, the guidance system including guidance means for guiding a surgical instrument relative to a guide direction; and indication means for providing an indicator on the anatomical structure corresponding to the guide direction. 
     In yet another form thereof, the present disclosure provides a method of performing an orthopaedic surgical procedure on an anatomical structure, including providing a guide instrument including at least one guide surface, the at least one guide surface extending along a guide direction; providing a light-emitting device associated with the guide instrument; and projecting an indicator from the light-emitting device onto the anatomical structure corresponding to the guide direction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above mentioned and other features of this disclosure, and the manner of attaining them, will become more apparent and will be better understood by reference to the following description of embodiments of the disclosure taken in conjunction with the accompanying drawings, wherein: 
         FIG. 1  is a perspective view of a cut guide and cut plane indicator device according to one embodiment of the present disclosure; 
         FIG. 2  is another perspective view of the cut guide and cut plane indicator device of  FIG. 1 ; 
         FIG. 3  is an exploded view of the cut guide and cut plane indicator device of  FIG. 1 ; 
         FIG. 4  is an end view of the cut guide of  FIG. 1 ; 
         FIG. 5  is a side view of the cut guide of  FIG. 4 ; 
         FIG. 6  is another perspective view of the cut guide of  FIG. 4 ; 
         FIG. 7  is a perspective view of the cut plane indicator device of  FIG. 1 ; 
         FIG. 8  is another perspective view of the cut plane indicator device of  FIG. 7 ; 
         FIG. 9  is another perspective view of the cut guide and cut plane indicator device of  FIG. 1 ; 
         FIG. 10  is a perspective view of the cut guide and cut plane indicator device positioned to guide a first cut of a femur during a knee arthroplasty procedure; 
         FIG. 11  is another perspective view of the cut guide and cut plane indicator device positioned to guide a second cut of a femur during a knee arthroplasty procedure; 
         FIG. 12  is a perspective view of another cut guide with which the cut plane indicator device of  FIG. 7  may be used; and 
         FIG. 13  is a perspective view of a drill guide. 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. Although the drawings represent embodiments of the present disclosure, the drawings are not necessarily to scale and certain features may be exaggerated in order to better illustrate and explain the present disclosure. Although the exemplifications set out herein illustrate embodiments of the disclosure, the embodiments disclosed below are not intended to be exhaustive or to be construed as limiting the scope of the disclosure to the precise forms disclosed. 
     DETAILED DESCRIPTION 
     Referring to  FIGS. 1-9 , an assembly of cut guide  10  and cut plane indicator device  26  according to one embodiment of the present disclosure will now be described. As illustrated in  FIGS. 1-6 , cut guide  10  generally includes adapter portion  12  and cut block  16  extending outwardly from adapter portion  12 . Cut guide  10  may be operably coupled to a computer assisted surgery (CAS) system, for example, a robotic surgical system or haptic device, such as the BRIGIT system (Bone Resection Instrument Guidance System by Intelligent Telemanipulator), available from Zimmer, Inc. of Warsaw, Ind., and described in U.S. patent application Ser. No. 11/610,728, entitled AN IMAGELESS ROBOTIZED DEVICE AND METHOD FOR SURGICAL TOOL GUIDANCE, filed Dec. 14, 2006, assigned to the assignee of the present application, the disclosure of which is hereby expressly incorporated herein by reference. Accordingly, adapter portion  12  may be configured to be coupled to the BRIGIT system and may include fastener receiving holes  14  through which fasteners (not shown) may extend to secure cut guide  10  to an arm of the BRIGIT system device. Alternatively, cut guide  10  may be adapted and configured to couple with any image-guided system, any imageless CAS system, any non-robotic system, or any robotic system. Moreover, cut guide  10  may be in the form of a more traditional, manually operated cut guide, such as cut guide  110  illustrated in  FIG. 12  and discussed below, or in the form of the cut guides disclosed in U.S. Patent Application Publication No. 2004/0153066, entitled APPARATUS FOR KNEE SURGERY AND METHODS OF USE, filed on Feb. 3, 2003, assigned to the assignee of the present application, the disclosure of which is hereby expressly incorporated herein by reference. 
     Referring to  FIGS. 1-6 , cut guide  10  may include a plurality of cut guide slots  18 ,  18   a - 18   d  extending through cut block  16  at various angles. Each of cut guide slots  18 ,  18   a - 18   d  extends along and defines a cut guide plane, which is exemplified with respect to cut guide slot  18  as cut guide plane P ( FIGS. 1 ,  3 , and  6 ). Cut guide slots  18 ,  18   a - 18   d  are configured to receive therethrough a cutting or resection instrument, such as a saw, and to guide the cutting instrument along cut guide plane P. Alternatively, any surface of cut guide  10  may provide a cutting guide, such as the top surface of cut guide  10 , for example, to define cut guide plane P. 
     Referring now to  FIGS. 1-3  and  7 - 9 , cut plane indicator device  26  generally includes body  28 , laser or light-emitting indicator source  30  disposed within body  28 , and paddles or tabs  32  extending outwardly from body  28 . Body  28  defines a battery compartment (not shown) accessible by battery compartment door  38 . The battery compartment may house a battery (not shown), which is operably coupled to laser  30  to provide power thereto. Alternatively, laser  30  may be electrically coupled to the CAS system, such as by a power wire/cord, thereby deriving power from the CAS system. Cut plane indicator device  26  also includes on/off switch  34  which couples the power source to laser  30  and controls the flow of power to laser  30 . As illustrated and described in further detail below, laser  30  may be a line-producing laser adapted to project a line  40  ( FIGS. 10 and 11 ) onto a surface. Laser  30  produces a beam of light (not shown) and includes a lens (not shown), which is adapted to refract the laser beam to produce laser output  36 . Laser output  36  projects line  40  ( FIGS. 10 and 11 ) onto a surface located distant from laser  30 . In one form, laser output  36  is generally fan-shaped such that line  40  produced on a distant surface generally extends across a wide portion of the surface to ensure that line  40  provides sufficient guidance during a surgical procedure. Laser  30  may be any suitable line-producing laser that does not cause biological damage to the surface on which line  40  is projected. In one embodiment, laser  30  may include output  36  having two perpendicular lines  40 . The two perpendicular lines may provide a resection line, e.g., a horizontal line, and an alignment line, e.g., a vertical line, such that the alignment line aligns with a mechanical axis of a bone, for example. Laser  30  may include any one of a plurality of lenses which are adapted to refract the laser beam to produce laser output  36 . For example, one exemplary lens may provide output  36  with reference lines. In another exemplary embodiment, a lens may provide extreme dimensional limits of a proposed prosthesis, i.e., a medial-lateral dimension and an anterior-posterior dimension of the prosthesis, such that a surgeon may preoperatively assess the suitability of the prosthesis. In other embodiments, a lens may provide a circle output, a square output, or an outline of a proposed prosthesis. In an exemplary embodiment, the lenses of laser  30  are modular such that a first lens may be interchanged with a second lens. 
     Referring still to  FIGS. 1-3  and  7 - 9 , paddles  32  extend from body  28  and are aligned with output  36  projected by laser  30 . Paddles  32  are configured to fit within cut slots  18 ,  18   a - 18   d  to securely attach cut plane indicator  26  to cut guide  10 . When paddles  32  are received in one of slots  18 ,  18   a - 18   d , laser  30  is aligned with the cut plane of that slot. For instance, as illustrated in  FIG. 1 , when paddles  32  are positioned in cut slot  18 , laser  30  and output  36  projected by laser  30  are aligned along cut plane P of cut guide slot  18 . Accordingly, laser  30  projects output  36  through slot  18  along cut plane P. 
     Referring now to FIGS.  3  and  10 - 11 , operation of the cut guide  10 /cut plane indicator device  26  assembly will now be described. Cut guide  10  and cut plane indicator device  26  cooperate to facilitate the resection of the surface of a bone in preparation to receive a prosthetic implant. For instance, cut guide  10  and cut plane indicator device  26  may be used to prepare the bones of the knee joint during a knee arthroplasty procedure. 
     As shown in  FIGS. 10 and 11 , the knee joint generally includes tibia T and femur F. Femur F has distal end F d , posterior side F p  and anterior side F a , each of which may require cutting during the procedure in order to prepare femur F to receive the pre-selected implant. To make the cut of posterior side F p , the CAS system to which cut guide  10  may be attached moves cut guide  10  into position such that cut guide  10  is spaced from distal end F d  of femur F but cut plane P of cut slot  18  is properly positioned in the pre-determined cut plane to guide the cut of posterior side F p . The CAS system may use any known methods for determining and effecting the proper placement of cut plane P. Such methods may include first performing known preliminary-operation (pre-op) planning procedures to determine the appropriate size of implant. Pre-op procedures may include obtaining measurements of and/or producing a 3-dimensional model of the patient&#39;s femur from CT scans, x-rays, or other known methods. The CAS surgery methods may also employ a haptic device or probe, which touches femur F and obtains coordinates from which a 3-dimensional representation of femur F can be created. The CAS system may use parameters for the pre-selected implant and the coordinates of femur F to calculate the cut planes of the cuts to be made to femur F. Some of these pre-op procedures are described in U.S. patent application Ser. No. 11/610,728, entitled AN IMAGELESS ROBOTIZED DEVICE AND METHOD FOR SURGICAL TOOL GUIDANCE, incorporated by reference above. 
     Cut plane indicator device  26  may be coupled to cut guide  10  by inserting paddles  32  into cut slot  18 , as illustrated in  FIG. 3 . As shown in  FIG. 10 , laser  30  projects output  36  through slot  18  along cut plane P and onto distal end F d  of femur F to produce cut plane indicator line  40 . Cut plane indicator line  40  provides the surgeon with a visual indication or cue indicating the location of the cut of posterior side F p  of femur F. At this point, the surgeon can decide whether the depth, angle, and position of cut plane P and/or the initial implant size selection are appropriate. If appropriate, the surgeon may proceed to cut posterior side F p  of femur F by disengaging cut plane indicator device  26  from cut guide  10  and instructing the CAS system to move cut guide  10  closer to and/or against distal end F d  of femur F while maintaining cut plane P in the same orientation relative to femur F. The CAS system may be adapted to fix cut guide  10  to move in a single plane; therefore, the movement of cut guide  10  closer to distal end F d  of femur F is directed only along cut plane P. Once cut guide  10  is in position, the surgeon may insert the cutting instrument through slot  18  and into femur F to cut posterior side F p  along cut plane P. Alternatively, the surgeon may leave cut plane indicator device  26  engaged with cut guide  10  and may use laser line  40  as a guide to free-hand cut posterior side F p  of femur F. The surgeon may also inspect the accuracy of the resulting cut surface by projecting laser output  36  across the cut surface. Laser output  36  would then reveal and indicate any areas lying above the cut plane that may have been missed by the saw. 
     Turning now to  FIG. 11 , cut plane indicator device  26  may be similarly used to verify the angle, position and depth of cut plane P when making a cut of distal end F d  of femur F. The CAS system moves cut block  16  into a position such that cut block  16  is spaced from femur F but cut plane P is properly positioned on a pre-determined cut plane to guide the cut of distal end F d . In this position, laser  30  ( FIG. 10 ) of cut plane indicator device  26  projects line  40  onto anterior surface F a  of femur F. Line  40  provides the surgeon with a visual indication or cue indicating the location of the cut on anterior surface F a . From viewing line  40 , the surgeon can decide whether the depth, angle, and position of cut plane P are appropriate. If cut plane P is appropriate, line  40  may then be used to guide the surgeon in making a free-hand cut of distal end F d  if so desired. Otherwise, cut plane indicator device  26  may be removed from cut block  16 , cut block  16  may be moved closer to femur F, and cut slot  18  ( FIG. 10 ) can be used to guide the saw in making the cut of F d . This procedure may be repeated for all of the necessary cuts of femur F. 
     It should be understood that cut plane indicator device  26  may be used with alternative existing cut guides and cut blocks, including those designed to be used manually rather than with a CAS system. For instance,  FIG. 12  illustrates known femoral finishing guide  110 , such as the NEXGEN Femoral Finishing Guide, available from Zimmer, Inc. of Warsaw, Ind., for example, which includes cut block  116  and a plurality of cut guide slots  118   a - 118   c  extending through cut block  116 . Referring to  FIGS. 7-8  and  12 , paddles  32  of cut plane indicator device  26  may be inserted into any one of slots  118   a - 118   c  in a manner similar to that described above with respect to cut guide  10 . In this position, laser output  36  projected by laser  30  extends through the slot and projects a line along the plane of the slot. Other examples of femoral cut guides with which cut plane indicator device  26  may be used include those guides disclosed in U.S. Patent Application Publication No. 2004/0153066, incorporated by reference above; and U.S. Patent Application Publication No. 2006/0200158, entitled APPARATUSES AND METHODS FOR ARTHROPLASTIC SURGERY, filed on Jan. 27, 2006, assigned to the assignee of the present application, the disclosure of which is hereby expressly incorporated herein by reference. 
     The examples above illustrate cut plane indicator device  26  being used with femoral cut guides. However, it should be understood that the use of cut plane indicator device  26  is not limited to this particular use. Rather, cut plane indicator device  26  may be used with any cut guide, including tibial cut guides such as, for example, those disclosed in U.S. Patent Application Publication No. 2006/0200158, incorporated by reference above; and U.S. patent application Ser. No. 11/343,849, entitled TIBIAL CUT GUIDE ASSEMBLY HAVING ROTATABLE CUT GUIDE BODY, filed on Jan. 31, 2006, assigned to the assignee of the present application, the disclosure of which is hereby expressly incorporated herein by reference. As noted, cut plane indicator device  26  may be adapted for use with any cut guide and, therefore, is also not limited to use with cut guides for knee arthroplasty. Moreover, indicator device  26  may also be adapted to be used with a drill guide. For example, laser  30  of indicator device  26  may be a point laser such that, when oriented to have a laser output extend through a drill guide, the laser output provides a reference point on an anatomical structure which may be used to guide a surgeon during a drilling procedure.  FIG. 13  shows an exemplary drill guide  50  including drill guide throughbores  52  through which a laser may be oriented to project an output aligned along drill axis  54  onto an anatomical structure. 
     In one method for surgery on an anatomical structure according to an exemplary embodiment of the present disclosure, cut guide  10  may be attached to a robotic device, such as the BRIGIT system via adapter portion  12 . The BRIGIT system may be used to obtain a plurality of landmarks on the anatomical structure to provide guidance, such as a frame of reference relative to the patient, for the BRIGIT system. The robotic device may then be switched to a free state in which a user, such as a surgeon, may freely manipulate an arm of the device to which cut guide  10  is attached and manually position cut guide  10 , with cut plane indicator device  26  attached thereto, proximate the anatomical structure. Indicator source  30  of device  26  provides an indicator on the anatomical structure which identifies the location and/or depth of alteration to be accomplished with the current position of cut guide  10 , i.e., indicator source  30  provides an initial alignment of cut guide  10  relative to the anatomical structure. The surgeon manually may initially position cut guide  10  based on prior experience or knowledge, similar to positioning methods for conventional cut guides. An alignment rod may be positioned substantially perpendicular to cut guide  10  and aligned with a femoral head and an ankle in an exemplary embodiment wherein the anatomical structure is a femur. The alignment rod may be substantially similar to the alignment rod described in U.S. Pat. No. 7,094,241, entitled METHOD AND APPARATUS FOR ACHIEVING CORRECT LIMB ALIGNMENT IN UNICONDYLAR KNEE ARTHROPLASTY, issued Aug. 22, 2006, assigned to the assignee of the present disclosure, the disclosure of which is hereby expressly incorporated herein by reference. Aligning the alignment rod with the femoral head and the ankle provides an indication to the surgeon that the cut guide  10  is correctly positioned. Cut guide  10  may be manually rotated until such alignment is achieved. The robotic device then is instructed to hold the current position of cut guide  10  and the alignment rod may be removed. The robotic device may then be used by the surgeon to provide small adjustments for such factors as varus/valgus, resection level, and flexion/extension adjustment. The surgeon may then use the robotic device to lock cut guide  10  into a final position after which the resection may be completed, as described above. 
     The embodiments illustrated and described above show cut plane indicator device  26  as a separate device removable from the cut block and usable with a variety of different cut blocks. The present disclosure also contemplates an embodiment wherein the cut plane indicator device is built into the cut block. In this case, the cut plane indicator device would include a laser housed within an opening in the cut block and aligned along the cut plane of a slot of the cut block. 
     In one embodiment, laser  30  of indicator device  26  may be used as a device used for overall limb alignment. For example, a surgeon or other user may use indicator device  26  as a leg alignment device. The surgeon may position laser  30  proximate a hip joint of a patient and orient output  36  of laser  30  to assess whether a femoral head, a knee joint, and an ankle joint of the patient are properly aligned. 
     While this disclosure has been described as having exemplary designs, the present disclosure may be further modified within the spirit and scope of this disclosure. This application is therefore intended to cover any variations, uses, or adaptations of the disclosure using its general principles. Further, this application is intended to cover such departures from the present disclosure as come within known or customary practice in the art to which this disclosure pertains.