Patent Publication Number: US-9839436-B2

Title: Patient-specific glenoid depth control

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part of U.S. patent application Ser. No. 14/295,021 filed on Jun. 3, 2014. The entire disclosure of the above application is incorporated herein by reference. 
    
    
     INTRODUCTION 
     In shoulder arthroplasty various guides and instruments are used to determine an alignment axis and guide an implant for anatomic or reverse shoulder arthroplasty. The present teachings provide various patient-specific and other instruments for use in shoulder arthroplasty. 
     SUMMARY 
     The present teachings provide various patient-specific instruments for anatomic and reverse shoulder arthroplasty. 
     Specifically, the present teachings provide a system for reaming a bone, including a patient-specific guiding wire configured to be attached to the bone, and a tubular depth guide configured to cover at least a portion of the patient-specific guiding wire. The tubular depth guide includes a first end configured to abut the bone, a second end opposite the first end, and has a patient-specific length. The system also includes a reaming device including an elongate recess therein that extends between a reaming tool of the reaming device and an interior of the reaming device, and a depth control window formed in an exterior surface of the reaming device, wherein the elongate recess is configured to receive each of the guiding wire and depth guide therein, and during reaming of the bone, the depth control window is configured to provide visual access to the second end of the tubular depth guide to determine whether a patient-specific reaming depth has been reached. 
     The present teachings also provide a method for reaming a bone, including attaching a guiding wire to the bone, and covering at least a portion of the guiding wire with a tubular depth guide. The tubular depth guide includes patient-specific length extending between a first end configured to abut the bone and a second end opposite the first end. The method also includes reaming the bone with a reaming device. The reaming device includes an elongate recess therein that is configured to receive each of the guiding wire and depth guide therein and extends between a reaming tool of the reaming device and an interior of the reaming device, and the reaming device including a depth control window formed in an exterior surface of the reaming device. Lastly, the method includes viewing the second end of the tubular depth guide through the depth control window to determine whether a patient-specific reaming depth has been reached. 
     The present teachings also provide a method for reaming a glenoid for an arthroplasty, including positioning a patient-specific glenoid guide proximate the glenoid, the glenoid guide including a first primary drill guide extending along a first axis and a second primary drill guide extending along a second axis; selecting one of the first and second axes for orienting a guiding wire, and positioning a guiding wire in the glenoid that extends along the selected axis; positioning a tubular depth guide over the guiding wire such that a first end of the depth guide abuts the bone and the guiding wire extends outward from a second of the depth guide; positioning a reaming device over the guiding wire, and reaming the glenoid along the selected axis, the reaming device including an elongate recess therein that is configured to receive each of the guiding wire and depth guide therein and extends between a reaming tool of the reaming device and an interior of the reaming device, and the reaming device including a depth control window formed in an exterior surface of the reaming device; and viewing the second end of the tubular depth guide through the depth control window to determine whether a patient-specific reaming depth has been reached 
     Further areas of applicability of the present teachings will become apparent from the description provided hereinafter. 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 teachings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present teachings will become more fully understood from the detailed description and the accompanying drawings. 
         FIG. 1  is an exploded view of a prior art implant for reverse shoulder arthroplasty; 
         FIG. 2  is an environmental view of the prior art implant of  FIG. 1 ; 
         FIG. 3A  is an environmental view illustrating a guiding pin used during reaming in reverse shoulder arthroplasty; 
         FIG. 3B  is an environmental view illustrating a guiding pin after reaming in reverse shoulder arthroplasty; 
         FIG. 4  is a perspective view of a prior art implant for anatomic shoulder arthroplasty; 
         FIG. 5  is perspective bottom view of a patient-specific glenoid guide for reverse and anatomic shoulder arthroplasty according to the present teachings; 
         FIG. 6  is a perspective view of a glenoid including a guiding pin and a depth guide used during reaming of the glenoid; 
         FIG. 7  is a perspective view of the depth guide illustrated in  FIG. 6 ; 
         FIG. 8  is a cross-sectional view of a reamer during reaming of the glenoid with the guiding pin and depth guide illustrated in  FIG. 6  received therein; 
         FIG. 8A  is a close-up of  FIG. 8  illustrating a portion of the reamer with the guiding pin and depth guide received therein; and 
         FIGS. 9-11  illustrate perspective views of the reamer according to a principle of the present disclosure. 
     
    
    
     Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings 
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is in no way intended to limit the present teachings, applications, or uses. 
     The present teachings generally provide patient-specific surgical instruments that include, for example, alignment guides, drill guides, and other tools for use in shoulder joint replacement, shoulder resurfacing procedures and other procedures related to the shoulder joint or the various bones of the shoulder joint, including the glenoid face or cavity of the scapula, the humeral head and adjacent shoulder bones. The present teachings can be applied to anatomic shoulder replacement and reverse shoulder replacement. The patient-specific instruments can be used either with conventional implant components or with patient-specific implant components and/or bone grafts that are prepared using computer-assisted image methods according to the present teachings. Computer modeling for obtaining three-dimensional images of the patient&#39;s anatomy using medical scans of the patient&#39;s anatomy (such as MRI, CT, ultrasound, X-rays, PET, etc.), the patient-specific prosthesis components and the patient-specific guides, templates and other instruments, can be prepared using various commercially available CAD programs and/or software available, for example, by Object Research Systems or ORS, Montreal, Canada. 
     The patient-specific instruments and any associated patient-specific implants and bone grafts can be generally designed and manufactured based on computer modeling of the patient&#39;s 3-D anatomic image generated from medical image scans including, for example, X-rays, MRI, CT, PET, ultrasound or other medical scans. The patient-specific instruments can have a three-dimensional engagement surface that is complementary and made to substantially mate and match in only one position (i.e., as a substantially negative or mirror or inverse surface) with a three-dimensional bone surface with or without associated soft tissues, which is reconstructed as a 3-D image via the aforementioned CAD or software. Very small irregularities need not be incorporated in the three-dimensional engagement surface. The patient-specific instruments can include custom-made guiding formations, such as, for example, guiding bores or cannulated guiding posts or cannulated guiding extensions or receptacles that can be used for supporting or guiding other instruments, such as drill guides, reamers, cutters, cutting guides and cutting blocks or for inserting guiding pins, K-wire, or other fasteners according to a surgeon-approved pre-operative plan. 
     In various embodiments, the patient-specific instruments of the present teachings can also include one or more patient-specific tubular guides for receiving and guiding a tool, such as a drill or pin or guide wire at corresponding patient-specific insertion points and orientations relative to a selected anatomic or reverse axis for the specific patient. The patient-specific instruments can include guiding or orientation formations and features for guiding the implantation of patient-specific or off-the-shelf implants associated with the surgical procedure. The geometry, shape and orientation of the various features of the patient-specific instruments, as well as various patient-specific implants and bone grafts, if used, can be determined during the pre-operative planning stage of the procedure in connection with the computer-assisted modeling of the patient&#39;s anatomy. During the pre-operative planning stage, patient-specific instruments, custom, semi-custom or non-custom implants and other non-custom tools, can be selected and the patient-specific components can be manufactured for a specific-patient with input from a surgeon or other professional associated with the surgical procedure. 
     Referring to  FIGS. 1-2 , a prior art reverse shoulder implant  10  is illustrated. The reverse shoulder implant  10  includes a humeral stem  12 , a humeral tray  14 , a humeral bearing  16 , a glenosphere  18  and a baseplate  20  having a plate portion  22  and a central boss  24 . The humeral stem  12  is implanted in the humeral bone  26  and has a proximal end  28  coupled via a Morse taper connection to a male taper  30  extending from a plate  32  of the humeral tray  14 . The glenosphere  18  can be modular and include a head  34  articulating with the bearing  16  and an offset double-taper component  36 . The double-taper component  36  has a first tapered portion  38  coupled to a corresponding tapered opening  40  of the head  34  and a second tapered portion  42  coupled to the central boss  24  of the glenoid baseplate  20 . A central screw  44  passes through the baseplate  20  into the glenoid face  46  of the patient&#39;s scapula. Peripheral screws  48  are used to lock the baseplate  20  in the glenoid face  46 . 
       FIG. 3A  illustrates using a guiding pin  50  to guide reaming of the glenoid face  46  in reverse shoulder arthroplasty using a reaming device  52 .  FIG. 3B  illustrates the guiding pin  50  through a hole  54  drilled through the glenoid face  46 . The guiding pin  50  is used to guide placement of a reverse or anatomic implant, as discussed below. 
     Referring to  FIG. 4 , a prior art anatomic shoulder implant  56  is illustrated. The anatomic shoulder implant  56  includes a humeral stem  58 , a glenosphere  60  and a bearing  62  with peripheral pegs  64  and a removable or non-removable central peg  66 . 
     Referring to  FIG. 5 , an exemplary patient-specific glenoid guide  68  is illustrated. Patient-specific guide  68  and operation thereof is fully described in U.S. patent application Ser. No. 13/653,868 filed Oct. 17, 2012, the entire disclosure of which is hereby incorporated by reference. The patient-specific glenoid guide  68  is configured to guide a guiding pin (such as the guiding pin  50  shown in  FIGS. 3A and 3B ) and provide an implant alignment orientation for reverse as well as anatomic shoulder arthroplasty at the surgeon&#39;s discretion. 
     The glenoid guide  68  has an upper (or outer) surface  70  and a lower (or inner) or anatomy-engaging and patient-specific surface  72  that references (substantially as a negative or inverse or mirror) the glenoid face  46  and may include all or a portion of the labrum, i.e., the peripheral cartilaginous structure that encircles and deepens the glenoid face  46 . Alternatively, the labrum can be completely removed such that the patient-specific glenoid surface  72  references and mirrors only the bone surface of the glenoid cavity or glenoid face  46 . Optionally, the glenoid guide  68  can include a peripheral portion or peripheral lip  74  with a corresponding patient-specific peripheral surface  76  that engages a corresponding peripheral surface or glenoid rim around the scapula of the patient. A first (or anatomic) elongated tubular drill guide  78  can extend from the upper surface  70  of the glenoid guide  68  at a specific location and along a first axis A that is determined and designed according to the pre-operative plan of the patient to define a patient-specific anatomic alignment axis and insertion point for a guiding pin  50 . 
     A second (or reverse) elongated tubular drill guide  80  can extend from the upper surface  70  of the glenoid guide along a second axis B that is determined and designed according to the pre-operative plan of the patient to define a patient-specific reverse alignment axis and insertion point for a guiding pin  50 . The reverse alignment axis B can have a predetermined inferior tilt relative to the anatomic alignment axis A, such as, for example, a ten-degree inferior tilt. The first and second drill guides  78 ,  80  define corresponding elongated bores for guiding a drill bit and/or inserting an alignment pin or guiding pin  50 . Each drill guide  78 ,  80  can include elongated openings or viewing windows  82  therethrough. The anatomic drill guide  78  and the reverse drill guide  80  can include corresponding visual and/or tactile markings  84 ,  86  indicating their corresponding functions for easy identification and to avoid confusion. The markings can be, for example, elevated lettering using the words ANATOMIC for marking  84  and REVERSE for marking  86 . Additionally, marking  88  can be provided with other patient-specific information, such as, for example, patient identification, procedure, etc. 
     Referring to  FIGS. 3A, 3B, and 4 , the glenoid guide  68  can be used for anatomic or reverse arthroplasty to drill a hole  54  into the glenoid face  46  through the anatomic or reverse drill guides  78 ,  80  and insert a guiding pin or other K-wire  50 . The guiding pin  50  can be used to guide the predetermined alignment of the bearing  62  in the glenoid face  46  for implantation in anatomic arthroplasty. Alternatively, the guiding pin  50  can be used to guide the reaming and boring of the glenoid face  46  necessary before the predetermined alignment and implantation of the baseplate  20  shown in  FIG. 2  in the glenoid face  46  for reverse arthroplasty. 
     Once guiding pin  50  has been inserted into glenoid  46 , reaming device  52  can be used to ream glenoid  46  to form hole  54  in the glenoid  46 . It is important to control reaming depth so that bearing  62  or baseplate  20  can be properly fitted with hole  54 . In addition, it is important to control reaming depth so that the bone can be preserved, and so that joint tension can be more accurately controlled. Accordingly, a patient-specific depth guide  90  that prevents reaming device  52  from reaming glenoid  46  to too great a depth can be used. 
     As best shown in  FIGS. 6 and 7 , depth guide  90  can be formed from a hollow tube  91  including a length L, a width W (outer diameter), and an inner diameter ID. Depth guide  90  can be formed from materials such as titanium, CoCr or steel. Alternatively, depth guide  90  can be formed from polymeric materials such as polyethylene, polypropylene, polystyrene, nylon, and polyether ether ketone (PEEK). Inner diameter ID is selected to receive guiding wire  50  snugly therein. Accordingly, after guiding pin  50  has been inserted into glenoid  46  and before reaming has begun, depth guide  90  can be placed over guiding wire  50  and moved to abut glenoid  46 . 
     Depth guide  90  includes a first end  92  configured to abut glenoid  46 , and a second end  94  configured to abut a surface within reamer  52 . First end  92  may be patient-specific such that first end  92  is contoured to mate with the patient-specific contours of glenoid face  46 . In other words, first end  92  that abuts glenoid face  46  may be a negative surface of a portion of the glenoid face  46  that the first end  92  contacts such that first end  92  will only mate with the glenoid face  46  in a single position. Regardless, depth guide  90  is preferably tubular or cylindrical in shape, but any shape may be used without departing from the scope of the present teachings so long as depth guide  90  may be received within reaming device  52 . An outer surface  93  of depth guide  90  may be smooth, or may be formed to include apertures (not shown) that reduce the amount of material required to form depth guide  90 . 
     Referring to  FIGS. 8 and 8A , it can be seen that reaming device  52  includes an elongate recess  96  that extends from reaming tool  97  into an interior of a handle  99  of reaming device  52 . Elongate recess  96  is configured to receive guiding wire  50  and depth guide  90  therein. In addition, it can be seen that recess  96  includes a reduced diameter section  98  that defines a shoulder  100 . Second end  94  of depth guide  90  abuts shoulder  100  during reaming of glenoid  46 , and prevents reaming device  52  from reaming too great a depth into glenoid  46 . Accordingly, depth guide  90  of the present teachings acts to provide a physical stop for glenoid reaming. More specifically, as reaming device  52  begins cutting into glenoid  46 , second end  94  of depth guide  90  will be spaced apart from shoulder  100 . Once reaming device  52  has cut to the patient-specific depth, however, second end  94  of depth guide  90  will abut shoulder  100  and prevent reaming device  52  from cutting or reaming any further. 
     Depth guide  90  can be patient-specific such that a depth of reaming can be determined preoperatively. In this regard, the length L of depth guide  90  can be determined preoperatively to control reaming depth. Because reaming device  52  includes shoulder  100 , reaming device  52  is made to reference the patient-specific depth guide  90  such that the cutting depth of the reaming device  52  is limited to the patient-specific depth for both anatomic and reverse glenoid reaming. It should be understood, however, that after the reaming depth has been reached and reaming device  52  is removed from guiding wire  50 , the surgeon may inspect hole  54  formed by reaming device  52 . If the surgeon determines that the patient-specific depth is not satisfactory for accommodating the seize of the selected implant, depth guide  90  may be removed from guiding wire  50 . Reaming device  52  may then be aligned with guiding wire  50  without depth guide  90 , and reaming restarted to the depth desired by the surgeon intraoperatively. 
     In another embodiment, a plurality or kit of depth guides  90  having different lengths may be formed preoperatively. If during the course of reaming it is determined that a selected depth guide  90  prevents reaming to an adequate depth, the depth guide  90  may be removed and replaced by another depth guide having a shorter length. In this manner, the reaming depth can still be controlled to prevent over-reaming the glenoid  46 . 
     In addition to using depth guide  90  to patient-specifically control reaming depth, reaming device  52  may also be patient-specific. More specifically, as best shown in  FIG. 9 , reaming device  52  may include a visual depth control window  102  that provides visual access to an interior of reaming device  52  such that depth guide  90  may be visually inspected during reaming. Depth control window  102  is an elongated aperture  104  formed in an exterior surface  106  of reaming device  52 . Although not required by the present disclosure, depth control window  102  may include a first window  108  and a second window  110 , with the first and second windows  108  and  110  being separated by a rib  112 . 
     Rib  112  may separate first and second windows  108  and  110  at a patient-specific location that corresponds to the patient-specific reaming depth provided by depth guide  90 . In this regard, the location of rib  112  may correspond to the location of shoulder  100  within reaming device  52 . Alternatively, reaming device  52  may not include shoulder  100  and rib  112  will correspond to the above-noted patient-specific reaming depth provided by depth guide  90  such that when end  94  of depth guide  90  reaches rib  112 , the surgeon will visually determine that the patient-specific reaming depth has been reached. Accordingly, depth control window  102  may be configured pre-operatively according to a specific patient such that a position of rib  112  and, therefore, the depth control window  102  is patient-specific. 
     As can be seen in  FIG. 10 , end  94  of depth guide  90  is visible in depth control window  102 , but has not yet reached rib  112 . Thus, the surgeon will be aware that the patient-specific reaming depth has not yet been reached. Now referring to  FIG. 11 , it can be seen that end  94  of depth guide  90  has reached rib  112 . Thus, the surgeon will be visually aware that the patient-specific reaming depth has been reached. As noted above, the visual indication provided by rib  112  may be in lieu of or in addition to the physical indication provided by contact between depth guide  90  and shoulder  100 . 
     In addition to depth control window  102 , reaming device  52  may also include visual markings or notches  114  formed in exterior surface  106 . Notches  114  correspond to various reaming depths that are less than or greater than the patient-specific reaming depth indicated by rib  112  or depth guide  90 . For example, notches  114  may include a first notch  114   a  that represents a reaming depth that is four millimeters less than that indicated by rib  112 , a second notch  114   b  may represent a reaming depth that is two millimeters less than that indicated by rib  112 , a third notch  114   c  may represent a reaming depth that is two millimeters greater than that indicated by rib  112 , and a fourth notch  114   d  may indicate a reaming depth that is four millimeters greater than that indicated by rib  112 . It should be understood, however, that notches  114  can indicate reaming depths different than the two millimeter increments noted above (e.g., any increment of one to ten millimeters is contemplated). Moreover, it should be understood that notches  114  may represent different lengths such as micrometers, nanometers, or any other length desired. 
     As set forth above, the present disclosure provides a patient-specific reaming system for preparing a shoulder for either an anatomic or reverse arthroplasty. The system includes a depth guide  90  having a patient-specific length that corresponds to a reaming depth that is determined pre-operatively. In addition, depth guide  90  may have an end  92  that abuts the glenoid face  46  that is patient-specific such that the depth guide  90  mates with the glenoid face  46  in only a single position. Further, the patient-specific depth guide  90  may be used in conjunction with a patient-specific reaming device  52 . In this regard, the patient-specific reaming device  52  includes a patient-specific depth control window  102  having a rib  112  that corresponds to the patient-specific depth provided by depth guide  90  such that when an end  94  of the depth guide  90  reaches the rib  112 , the surgeon will be visually aware that the patient-specific reaming depth has been reached. In addition, rib  112  may correspond to a shoulder  100  within reaming device  52  such that when end  94  abuts shoulder  100 , a physical indication will be provided to the surgeon in addition to the visual indication provided by rib  112  that the patient-specific reaming depth has been reached. 
     The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure. 
     Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.