US20200054351A1 - Patient-specific acetabular guides and associated instruments - Google Patents

Abstract

A patient-specific acetabular guide can be used for preparing an acetabulum of a patient to receive an acetabular implant. The acetabular guide includes a patient-specific engagement surface designed to be complementary and mateable with a corresponding surface of the patient's pelvic anatomy. The acetabular guide is designed during a pre-operative plan for the patient by a three-dimensional reconstruction of the anatomy of the patient using two-dimensional medical images. The patient-specific engagement surface has a first portion mateable with a portion of the acetabulum of the patient. The acetabular guide includes a guiding element that extends from the acetabular guide opposite to the first portion of engagement surface. The guiding element defines a bore designed to be oriented along an alignment axis for an acetabular implant when the acetabular guide is engaged to the acetabulum.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS
• This application claims the benefit of provisional application 61/446,660, filed Feb. 25, 2011.
• This application is a continuation-in-part of U.S. application Ser. No. 12/973,214, filed Dec. 20, 2010, which is a continuation-in-part of U.S. application Ser. No. 12/955,361 filed Nov. 29, 2010, which is a continuation-in-part of U.S. application Ser. Nos. 12/938,905 and 12/938,913, both filed Nov. 3, 2010, each of which is a continuation-in-part of U.S. application Ser. No. 12/893,306, filed Sep. 29, 2010, which is a continuation-in-part of U.S. application Ser. No. 12/888,005, filed Sep. 22, 2010, which is a continuation-in-part of U.S. application Ser. No. 12/714,023, filed Feb. 26, 2010, which is a continuation-in-part of U.S. application Ser. No. 12/571,969, filed Oct. 1, 2009, which is a continuation-in-part of U.S. application Ser. No. 12/486,992, filed Jun. 18, 2009, and is a continuation-in-part of U.S. application Ser. No. 12/389,901, filed Feb. 20, 2009, which is a continuation-in-part of U.S. application Ser. No. 12/211,407, filed Sep. 16, 2008, which is a continuation-in-part of U.S. application Ser. No. 12/039,849, filed Feb. 29, 2008, which: (1) claims the benefit of U.S. Provisional Application No. 60/953,620, filed on Aug. 2, 2007, U.S. Provisional Application No. 60/947,813, filed on Jul. 3, 2007, U.S. Provisional Application No. 60/911,297, filed on Apr. 12, 2007, and U.S. Provisional Application No. 60/892,349, filed on Mar. 1, 2007; (2) is a continuation-in-part U.S. application Ser. No. 11/756,057, filed on May 31, 2007, now U.S. Pat. No. 8,092,465, issued on Jan. 10, 2012, which claims the benefit of U.S. Provisional Application No. 60/812,694, filed on Jun. 9, 2006; (3) is a continuation-in-part of U.S. application Ser. No. 11/971,390, filed on Jan. 9, 2008, now U.S. Pat. No. 8,070,752, issued on Dec. 6, 2011, which is a continuation-in-part of U.S. application Ser. No. 11/363,548, filed on Feb. 27, 2006, now U.S. Pat. No. 7,780,672, issued on Aug. 24, 2010; and (4) is a continuation-in-part of U.S. application Ser. No. 12/025,414, filed on Feb. 4, 2008, which claims the benefit of U.S. Provisional Application No. 60/953,637, filed on Aug. 2, 2007.
• This application is continuation-in-part of U.S. application Ser. No. 12/872,663, filed on Aug. 31, 2010, which claims the benefit of U.S. Provisional Application No. 61/310,752 filed on Mar. 5, 2010.
• This application is a continuation-in-part of U.S. application Ser. No. 12/483,807, filed on Jun. 12, 2009, which is a continuation-in-part of U.S. application Ser. No. 12/371,096, filed on Feb. 13, 2009, which is a continuation-in-part of U.S. application Ser. No. 12/103,824, filed on Apr. 16, 2008, which claims the benefit of U.S. Provisional Application No. 60/912,178, filed on Apr. 17, 2007.
• This application is also a continuation-in-part of U.S. application Ser. No. 12/103,834, filed on Apr. 16, 2008, now U.S. Pat. No. 7,967,868, issued on Jun. 28, 2011, which claims the benefit of U.S. Provisional Application No. 60/912,178, filed on Apr. 17, 2007.
• This application is also a continuation-in-part of U.S. application Ser. No. 12/486,842, filed on Jun. 18, 2009, which is a continuation-in-part of U.S. application Ser. No. 12/358,664, filed on Mar. 24, 2009.
• The disclosures of the above applications are incorporated herein by reference.
INTRODUCTION
• The present teachings provide a patient-specific acetabular guide and related instruments for preparing an acetabulum to receive an acetabular implant and guiding the implant into the acetabulum of a patient.
SUMMARY
• The present teachings provide various instruments and methods for generally preparing the acetabulum of a patient to receive an acetabular implant, such as, for example, an acetabular cup along an alignment axis. The alignment axis and various patient-specific guides and instruments can be designed during a pre-operative plan using a three-dimensional reconstruction of the patient's relevant anatomy, such as the pelvis or portions thereof, including the acetabular and periacetabular areas of the pelvis. The three-dimensional reconstruction can be based on two-dimensional medical images, including MRI, CT or X-ray scans and prepared using commercially available imaging software.
• The present teachings provide, for example, an acetabular guide that includes a patient-specific engagement surface designed to be complementary and mateable with a corresponding surface of the patient's pelvic anatomy. The acetabular guide is designed during the pre-operative plan for the patient using the three-dimensional reconstruction of the anatomy of the patient. The patient-specific engagement surface has a first portion mateable with a portion of the acetabulum of the patient. The acetabular guide includes a guiding element that extends from the acetabular guide opposite to the first portion of engagement surface. The guiding element defines a bore designed to be oriented along an alignment axis for an acetabular implant when the acetabular guide is engaged to the acetabulum. A drilling element with a stop can be used to drill a pilot hole into the acetabulum along the alignment axis.
• The acetabular guide can be provided in various fitment options in which the patient-specific engagement surface is designed to fit in a unique position relative to the patient anatomy. Each fitment option of the acetabular guide includes a portion that covers a center of the acetabulum for aligning the acetabular implant and additional portions complementary to a portion of the acetabular rim and/or a portion of the transverse acetabular ligament. Each fitment option allows the acetabular guide to have a compact size, extend through the center of the acetabulum for alignment, and include portions that can fit over various anatomic landmarks in a unique position for the patient. The particular fitment option can be selected for each specific patient based on the patient's anatomy, the procedure to be performed and the surgeon's preference and/or technique.
• In other embodiments according to the present teachings, the acetabular guide can include first and second marker elements extending from a portion of the acetabular guide outside the acetabulum of the patient. The marker elements define corresponding first and second bores for guiding first and second marker pins into a bone portion of the patient. A secondary guide can be used with the marker pins to orient an acetabular cup into a predetermined position and orientation. The secondary guide can be designed during the pre-operative plan to include first and second guiding elements complementary to the first and second marker elements of the acetabular guide for receiving the first and second marker pins when the first and second marker pins are attached to the bone portion of the patient.
• The acetabular guide can be used according to the present teachings with a guiding handle support device that can be attached to the pelvis and provides an alignment rod as a reference for the alignment axis. The guiding handle can be removably attached to the guiding element of the acetabular guide along the alignment axis. The support device can include a connector supporting the alignment rod. The connector can be removably engaged with a shaft of the guiding handle. The support device includes rotational and translational mechanisms for orienting the alignment rod parallel to the shaft of the guiding handle and parallel to the alignment axis such that the alignment rod can provide a reference axis for the alignment axis.
• The present teachings also provide a reamer having a guiding pin. The guiding pin of the reamer can be received in the pilot hole that is drilled in the acetabulum through the bore of the guiding element of the acetabular guide. The guiding pin is thus oriented along the alignment axis. In some embodiments, the reamer includes a spring that biases the guiding pin and provides tactile feedback during reaming. In some embodiments, the reamer includes a plurality of removable arcuate blades. The blades can be disposable or replaceable. In some embodiments, each blade is attached to a corresponding supporting element shaped as a spherical section, such that the supporting elements collectively form a surface corresponding to a shape of the acetabular cup.
• The various instruments described above can be used in various combinations reaming the acetabulum and inserting an acetabular implant according to a pre-operative plan. In this regard the present teachings provide methods for reaming and preparing an acetabulum of a patient for an acetabular implant. One method includes engaging an acetabular area of the patient with a complementary surface of a patient-specific acetabular guide, supporting an alignment rod on a support device attached to the patient's pelvis and orienting the alignment rod to be parallel to an alignment axis for inserting the implant. The alignment axis is determined during a preoperative plan of the patient and coinciding with a center axis of a guiding element of the acetabular guide. The method further includes drilling a pilot hole in the acetabulum through a bore of the guiding element along the center axis, removing the acetabular guide, guiding an alignment pin of a reamer in the pilot hole such that the alignment pin is parallel to the alignment rod, and reaming the acetabulum.
• Another method according to the present teachings includes engaging an acetabular area of the patient with a complementary surface of a patient-specific acetabular guide. The acetabular guide is designed during a pre-operative plan from a reconstructed three-dimensional image of the patient's anatomy. The method includes drilling a pilot hole in the acetabulum through a bore of a guiding element of the acetabular guide along a patient-specific alignment axis determined by the guiding bore. The method also includes inserting first and second marker pins into an area outside the acetabulum of the patient through corresponding first and second marker elements of the acetabular guide. The method includes removing the acetabular guide without removing the marker pins, reaming the acetabulum, inserting an acetabular cup in the reamed acetabulum and sliding a secondary guide over the first and second marker pins. The method further includes engaging a planar arcuate surface of the secondary guide to a complementary rim surface of the acetabular cup to align the acetabular cup to a position and orientation determined in the pre-operative plan.
• Another method according to the present teachings includes using an electronic positioner for guiding an acetabular inserter into the acetabulum along a predetermined patient-specific alignment axis. The electronic positioner is capable of indicating a predetermined orientation using one or more orientation sensors. A patient-specific acetabular guide is placed on the acetabulum of the patient in a unique mated position. The acetabular guide has a guiding element oriented along the patient-specific alignment axis. A shaft of the acetabular inserter is inserted into the guiding element of the acetabular guide, such that the shaft of the acetabular inserter is oriented along the alignment axis. The electronic positioner is removably attached to the shaft of the acetabular inserter and is calibrated to indicate the alignment axis. After the acetabular guide is removed and the acetabulum prepared, the acetabular inserter with the acetabular implant can be guided along the alignment axis using feedback from the electronic positioner.
• 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, wherein:
• FIGS. 1-5 illustrate environmental perspective views of various patient-specific acetabular alignment guides according to the present teachings;
• FIG. 6 is an environmental perspective view of various instruments illustrating a method for establishing an acetabular cup insertion axis according to the present teachings;
• FIG. 7 is an environmental perspective view illustrating drilling a pilot hole for guided reaming according to the present teachings;
• FIG. 8A is an environmental perspective view illustrating a reamer for guided reaming according to the present teachings;
• FIG. 8B is a stylized perspective view of a reamer for guided reaming according to the present teachings;
• FIG. 80 is a partially sectioned perspective view of the reamer ofFIG. 8B;
• FIG. 9 is an environmental perspective view illustrating instruments for cup insertion according to the present teachings;
• FIG. 10 is an environmental perspective view of a patient-specific acetabular alignment guide with alignment pins for a secondary guide according to the present teachings;
• FIG. 11 is an environmental perspective view of another patient-specific acetabular alignment guide with alignment pins for a secondary guide according to the present teachings;
• FIG. 12 is an environmental perspective view of the patient-specific acetabular alignment guide ofFIG. 10 illustrating drilling a pilot hole for guided reaming according to the present teachings;
• FIG. 13 is an environmental perspective view of a secondary guide over the alignment pins ofFIG. 10 according to the present teachings;
• FIG. 14 is an environmental perspective view of a patient-specific acetabular alignment guide with an alignment pin and supporting instruments according to the present teachings;
• FIG. 15 is an environmental view of another embodiment of a patient-specific acetabular alignment guide shown with marker pins according to the present teachings;
• FIG. 16 is an environmental view of another embodiment of a secondary guide shown with marker pins according to the present teachings;
• FIG. 17 is an environmental view of another embodiment of a secondary guide shown with marker pins according to the present teachings;
• FIG. 18 is an environmental view illustrating a method of inserting an acetabular cup using the secondary guide ofFIG. 16 according to the present teachings;
• FIG. 19 is an environmental view illustrating another method of inserting an acetabular cup using an acetabular inserter coupled to the secondary guide ofFIG. 16 with an adaptor according to the present teachings;
• FIGS. 20A and 20B are perspective views of a detail of coupling between the acetabular inserter and the adaptor ofFIG. 19;
• FIG. 21 is a perspective view of another embodiment of an adaptor for coupling an acetabular inserter to a secondary guide according to the present teachings;
• FIG. 22 is an environmental perspective view illustrating calibrating an electronic positioner coupled to an acetabular inserter and using a patient-specific alignment guide without marker pins according to the present teachings;
• FIGS. 23A and 23B illustrate an acetabulum before and after reaming, respectively;
• FIG. 24 is an environmental perspective view illustrating inserting an acetabular cup using the calibrated positioner ofFIG. 22 according to the present teachings;
• FIG. 25 is an environmental perspective view illustrating calibrating an electronic positioner coupled to an acetabular inserter and using a patient-specific alignment guide with marker pins according to the present teachings;
• FIGS. 26A and 26B illustrate an acetabulum before and after reaming, respectively, using a secondary guide for alignment during reaming according to the present teachings;
• FIG. 27 is an environmental perspective view illustrating inserting an acetabular cup using the calibrated positioner and secondary guide ofFIG. 25 according to the present teachings;
• FIG. 28 is a perspective view of an electronic positioner coupled to an acetabular inserter/impactor as disclosed in commonly assigned U.S. Patent Publication 2010/0249796; and
• FIG. 29 is a schematic view of the electronic positioner ofFIG. 28.
DESCRIPTION OF VARIOUS EMBODIMENTS
• 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 various patient-specific acetabular alignment guides, secondary guides, reamers, inserters, impactors and other associated instruments for use in orthopedic surgery, such as in joint replacement or revision surgery, for example. The patient-specific alignment guides and associated instruments can be used either with conventional or with patient-specific implant components prepared with computer-assisted image methods.
• As described in commonly assigned U.S. application Ser. No. 11/756,057, filed on May 31, 2007, during a preoperative planning stage, imaging data of the relevant anatomy of a patient can be obtained at a medical facility or doctor's office. The imaging data can include, for example, a detailed scan of a pelvis, hip, knee, ankle or other joint or relevant portion of the patient's anatomy. The imaging data can be obtained using an MRI, CT, and X-Ray, ultrasound or any other imaging system. The imaging data obtained can be used to construct a three-dimensional computer image of the joint or other portion of the anatomy of the patient and prepare an initial pre-operative plan that can include bone or joint preparation, including planning for resections, milling, reaming, broaching, implant selection and fitting, design of patient-specific guide, templates, tools and alignment protocols for the surgical procedure.
• Computer modeling for obtaining three-dimensional computer images of the relevant patient's anatomy can be provided by various CAD programs and/or software available from various vendors or developers, such as, for example, from Materialise USA, Plymouth, Mich. The computer modeling program can be configured and used to plan a preoperative surgical plan, including planning various bone preparation procedures, to select or design/modify implants and design patient-specific guides and tools including patient-specific prosthesis components, and patient-specific tools, including reaming, broaching, milling, drilling or cutting tools, alignment guides, templates and other patient-specific instruments.
• The pre-operative plan can be stored in any computer storage medium, in a computer file form or any other computer or digital representation. The pre-operative plan, in a digital form associated with interactive software, can be made available via a hard medium, a web-based or mobile or cloud service, or a cellular portable device to the surgeon or other medical practitioner, for review. Using the interactive software, the surgeon can review the plan, and manipulate the position of images of various implant components relative to an image of the anatomy. The surgeon can modify the plan and send it to the manufacturer with recommendations or changes. The interactive review process can be repeated until a final, approved plan, is sent to a manufacturing facility for preparing the actual physical components.
• After the surgical plan is approved by the surgeon, patient-specific implants and associated tools, including, for example, alignment guides, cutting/milling/reaming/broaching or other tools for the surgical preparation of the joint or other anatomy portion of the specific patient can be designed using a CAD program or other three-dimensional modeling software, such as the software provided by Materialise, for example, according to the preoperative surgical plan. Patient-specific guides and other instruments can be manufactured by various stereolithography methods, selective laser sintering, fused deposition modeling or other rapid prototyping methods. In some embodiments, computer instructions of tool paths for machining the patient-specific guides and/or implants can be generated and stored in a tool path data file. The tool path data can be provided as input to a CNC mill or other automated machining system, and the tools and implants can be machined from polymer, ceramic, metal or other suitable material depending on the use, and sterilized. The sterilized tools and implants can be shipped to the surgeon or medical facility for use during the surgical procedure.
• Patient-specific implants, guides, templates, tools or portions thereof are defined herein as those constructed by a surgical plan approved by the surgeon using thee-dimensional images of the specific patient's anatomy and made to closely conform and mate substantially as a negative mold or negative surface or inverse or mirror surface of corresponding surface portions of the patient's anatomy, including bone surfaces with or without associated soft tissue, such as articular cartilage, for example, depending on the particular procedure, implant and tool use.
• Patient-specific alignment guides and implants are generally configured to match the anatomy of a specific patient and can fit in only one position on a corresponding surface of the specific patient because anatomic features that are unique to each patient function as landmarks and can guide placement of the alignment guide or implant in only one position without the need of intraoperative navigation, patient marking or other intraoperative guidance. The patient-specific alignment guides are generally configured and manufactured using computer modeling based on the patient's 3-D anatomic image and have an engagement surface that is made to conformingly contact and match as a mirror or negative or inverse surface to a corresponding surface of a three-dimensional image/model of the patient's bone surface (with or without cartilage or other soft tissue), by the computer methods discussed above. The patient-specific alignment guides 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 pins or other fasteners according to a surgeon-approved pre-operative plan. The patient-specific alignment guides can be used in minimally invasive surgery, and also in surgery with multiple minimally-invasive incisions. Various alignment guides and pre-operative planning procedures are disclosed in commonly assigned and co-pending U.S. patent application Ser. No. 11/756,057, filed on May 31, 2007, U.S. patent application Ser. No. 12/211,407, filed Sep. 16, 2008; U.S. patent application Ser. No. 11/971,390, filed on Jan. 9, 2008, U.S. patent application Ser. No. 11/363,548, filed on Feb. 27, 2006; and U.S. patent application Ser. No. 12/025,414, filed Feb. 4, 2008. The disclosures of the above applications are incorporated herein by reference.
• Referring toFIGS. 1-5, the present teachings provide various patient-specific acetabular guides100,200. The acetabular guides100,200 can be used in connection with various other instruments to facilitate guided reaming of anacetabulum82 of apelvis80 of a specific patient and guided insertion and implantation of an acetabular implant or acetabular cup in theacetabulum82. Further, the patient-specific acetabular guides100,200 engage theacetabulum82 of the specific patient in a unique (only one) position and can provide an accurate alignment axis relative to the planned orientation of the acetabular cup280 (shown inFIG. 9, for example). The patient-specific acetabular guides100,200 can also provide secure fitting and rotational stability in a design that is lightweight with minimal size and bulk.
• FIGS. 1-3 illustrate a patient-specific acetabular guide100 having a patient-specific body102, as described below, and a guiding orpilot element104 having anelongated bore106 with a patient-specific alignment axis A for drilling a pilot hole on the acetabulum and/or establishing the alignment axis A for a reamer, implant inserter, impactor or other instruments used in the preparation and implantation procedure. The alignment axis A is configured to be central to the acetabular cup and perpendicular to the acetabular cup's surface when theacetabular guide100 is positioned on theacetabulum82. The alignment axis A helps orient and guide the acetabular implant and various related instruments along a patient-specific orientation established during the pre-operative plan for the patient. Theacetabular guide100 can be provided in various fitment options depending on the planned exposure of theacetabulum82 for the reaming procedure and implantation. Each fitment option of the acetabular guide can generally include a portion that covers a center of the acetabulum for aligning the acetabular implant and additional portions complementary to a portion of the acetabular rim and/or a portion of the transverse acetabular ligament. Each fitment option allows theacetabular guide100 to have a compact size, extend through the center of theacetabulum82 for alignment, and include portions that can fit over various anatomic landmarks in a unique position for the patient. The particular fitment option can be selected for each specific patient based on the patient's anatomy, the procedure to be performed and the surgeon's preference and/or technique.
• Three exemplary fitment options designated100A,100B and100C are illustrated inFIGS. 1-3, respectively. The fitment options can include fitments engaging or registering to various combinations of portions of the acetabulum82, theacetabular rim84 and thetransverse acetabular ligament83. For example, theacetabular guide100 in thefitment option100A may engage a portion of the acetabulum82, a portion of theacetabular rim84 and a portion of thetransverse acetabular ligament83. In thefitment option100B, theacetabular guide100 may engage a portion of theacetabulum82 and a portion of theacetabular rim84. In thefitment option100C, theacetabular guide100 may engage a portion of theacetabulum82 and a portion of thetransverse acetabular ligament83. Further details are discussed below. Either one or several acetabular guides100A,100B,1000 corresponding to different fitment options can be provided to the surgeon for intra-operative flexibility and plan change, according to the surgeon's preference. Theacetabular guide100 can be secured to the patient's bone with bone pins, guide wires or other fasteners.
• The patient-specific body102 of theacetabular guide100 can include aninner portion102a(all fitment options) from which the guiding element extends and which is designed to engage theacetabulum82, anouter portion102bwhich extends from theinner portion102aand is configured to extend over a portion of the rim84 (forfitment options100A and100C) and anouter portion102c(fitment options100A and1000) configured to extend over a portion of the transverse acetabular ligament83 (and adjacent area of the acetabulum82). The patientspecific body102 has an underside three-dimensional engagement surface108 that is custom-made or patient-specific to conform to and mirror (as a negative or inverse or mirror surface) complementary surfaces of various combinations of the acetabulum82,rim84 and/ortransverse acetabular ligament83 or other periacetabular surfaces of thepelvis80 of the specific patient, as described above in connection with the various fitment options. The patientspecific body102 is designed by using a three-dimensional image or model of theacetabulum82 and surrounding pelvic area of the patient, as described above. Theengagement surface108 enables theacetabular guide100 to nest or closely mate relative to the complementarily acetabular surface of the patient. Theacetabular guide100 can be designed to have generally small thickness, such that it can form a lightweight three-dimensional shell from which the guidingelement104 extends opposite to the engagement surface. The guidingelement104 can be formed to be a monolithic or integral portion of theacetabular guide100. Alternatively, the guidingelement104 can be modularly and removably coupled to theacetabular guide100, using, for example, a threaded connection, snap-on connectors or other removable attachments.
• Referring toFIGS. 4 and 5, another patient-specific acetabular guide200 is illustrated with exemplary twofitment options200A and200B. Similarly to theacetabular guide100, theacetabular guide200 also includes a patient-specific body202 and a guiding orpilot element204 having anelongated bore206 with an alignment axis A configured to be central to the acetabular cup and perpendicular to the acetabular cup's surface when theacetabular guide200 is positioned on theacetabulum82. Theacetabular guide200 can include one or more marker elements250 (two are shown in the exemplary embodiments ofFIGS. 4 and 5), each having anelongated bore252 for guiding marker pins260. The marker pins260 can be used for supporting a secondary guide for another preparation method discussed below in reference toFIG. 12. The other features of theacetabular guide200 are similar to that of theacetabular guide100, such that theacetabular guide200 can also be used instead of theacetabular guide100. Theacetabular guide100 can be used for procedures in which themarker elements250 are not utilized, as described below. Theacetabular guide200 can be used for procedures in which themarker elements250 may or may not be utilized, as described below.
• The patient-specific body202 of theacetabular guide200 is generally similar to patient-specific body102 of theacetabular guide100, such that the patient-specific body202 can include aninner portion202afrom which the guiding element extends and which is designed to engage theacetabulum82, and anouter portion202bwhich extends from theinner portion202aand is configured to extend over arim portion84 of theacetabulum82. Theouter portion202bextends sufficiently beyond therim84 to the periacetabular area of pelvis to accommodate themarker elements250. The patientspecific body202 has an underside or bone-engaging three-dimensional engagement surface208 that is custom-made or patient-specific to conform and mirror (as an inverse or negative or mirror surface) complementary surfaces of selected portions of the acetabulum82, therim84 and the transverse acetabular ligament83 (depending on the fitment option) or other periacetabular surfaces of thepelvis80 of the specific patient by using a three-dimensional image or model of the acetabulum and surrounding pelvic area of the patient, as described above. Theengagement surface208 enables theacetabular guide100 to nest or closely mate relative to the complementarily acetabular surface of the patient. Theacetabular guide200 can be designed to have generally small thickness, such that it can form a lightweight three-dimensional shell from which the guidingelement204 andmarker elements250 extend.
• Referring toFIGS. 6-9, a method for reaming and preparing the acetabulum for an implant is described in connection with the patient-specific acetabular guides100. The acetabular guides200 can also be used, although themarker elements250 are not utilized in this method. Referring toFIG. 6, a patient-specific acetabular guide100 (or200) is placed in a unique position on the acetabulum/rim/transverse acetabular ligament depending on the fitment option and associated anatomic landmarks of the patient, as determined in the preoperative plan for the specific patient. Once positioned, the guidingelement104 establishes the alignment axis A for the specific patient. An elongated guiding handle300 can be attached to the guidingelement104 such that the center axis of the guidinghandle300 coincides with the alignment axis A. The guiding handle300 can include a proximalgripping portion302, anelongated shaft304 extending from the grippingportion302 and a couplingdistal portion306 which can be removably coupled to the guidingelement104, such that the guidinghandle300 is aligned along the alignment axis A. The connection can be a slidable or threadable or other connection between thedistal portion306 and the guidingelement104. Thedistal portion306 can include, for example, abore308 for receiving the guidingelement104. The guidingelement104 and thebore308 can be of sufficient length for the guidinghandle300 to be removably yet stably coupled to the guidingelement104 for indicating the alignment axis A without wobbling or other misaligning motion.
• With continuing reference toFIG. 6, a support device or jig oroutrigger400 can be secured on thepelvis80. Thesupport device400 can be used to orient an alignment pin orrod402 along an axis A′ parallel to the alignment axis A. More specifically, thesupport device400 can include a universalrotational adjustment mechanism406 and a pivotable/translational adjustment mechanism408 for removably engaging theshaft304 and aligning thealignment rod402 parallel to theshaft304 and, therefore, parallel to the alignment axis. In the exemplary embodiment ofFIG. 6, thesupport device400 can include aleg410 that can be attached to the bone with a bone fastener (not shown) through ahole412 of a foot orbase414 of theleg410. Thesupport device400 can also include anarm416 that is slidable coupled to theleg410 to allow for translational motion of thearm416 relative to theleg410. Thearm416 can have, for example, anelongated slot418 that slidably receives afastener head420 of afastener422, such as a screw or bolt that is received through adistal flange424 of theleg410. Theflange424 can also pivot relative to thearm416 about an axis B along the axis of theleg410 andfastener422. Thehead420 of thefastener422 can be rotated to lock theflange424 and theleg410 relative to thearm416. The interconnection of thearm416, theleg410 and thefastener422 collectively form the pivotable/translational adjustment mechanism408.
• With continued reference toFIG. 6, thearm416 can be substantially planar and include at a distal end ahousing426 forming a socket428 for aball430 at a distal end of aconnector432. The socket428 and theball430 form a universal (ball) joint of the universalrotational adjustment mechanism406 for rotationally adjusting theconnector432 relative to thearm416. After adjustment, the orientation of theconnector432 can be locked with a fastener436 through thehousing426. Theconnector432 supports thealignment rod402 and includes anengagement surface434 that can contact or engage theshaft304, by a snap-on or other quick connect/disconnect connection. Thesupport device400 can be adjusted using theadjustment mechanisms406,408 described above such that thealignment rod402 along axis A′ is parallel to the alignment axis A of theshaft304. In other words, thealignment rod402 can serve as a marker for the orientation of the alignment axis A to guide reaming and cup insertion procedures as discussed below.
• After thesupport device400 is locked in a position such that the orientation of thealignment rod402 along axis A′ is fixed and parallel to the alignment axis A, the guidinghandle300 is disengaged from theengagement surface434 of theconnector432 and theacetabular guide100 and is removed. Referring toFIG. 7, adrilling element440 can be guided through thebore106 of the guidingelement104 of theacetabular guide100 to drill apilot hole89 in theacetabulum82 along the alignment axis A, as shown inFIG. 8A. Thedrilling element440 can include astop442 at a pre-determined position to prevent over drilling or drilling through the wall of theacetabulum82. The depth of drilling and the location of thestop442 on thedrilling element440 can be determined during the pre-operative plan for the specific patient. Thesupport device400 andalignment rod402 remain attached to the pelvis as shown inFIG. 6, although not fully shown inFIG. 7. After thepilot hole89 is drilled, theacetabular guide100 is removed.
• Referring toFIG. 8A, areamer500 can be guided along the alignment axis A to ream theacetabulum82. Another embodiment of areamer500′ according to the present teachings is illustrated inFIGS. 8B and 8C. Thereamers500 and500′ can be used interchangeably and similar elements will be referenced with the same numerals herein below. The reamer500 (500′) can include a trocar orother guiding pin502 that is sized to fit and be received in thepilot hole89 of theacetabulum82 for stabilizing and guiding the reamer500 (500′) along the alignment axis A, i.e., at a predetermined location and orientation. This guided reaming arrangement enables the surgeon to recreate the preoperative planned position and orientation for reaming theacetabulum82 and implanting the acetabular component. Thealignment rod402 which is supported by thesupport device400 along the axis A′ that is parallel to the alignment axis A can also help to guide the reamer500 (500′).
• The reamer500 (500′) can include a plurality ofcurved reaming blades504 and a supportingshaft506 for a reamer driver or reamer handle. Thecurved blades504 can be attached to a plurality of curved supportingelements508 in the form of spherical leaves or spherical section/portions that collectively define a semi-spherical surface corresponding to the shape and size of the acetabular component to be implanted in the acetabulum after reaming. Theblades504 can be removable and replaceable or disposable. The entire reamer head that includes theblades504 and thesupport element508 can also be disposable. Areamer500 with fourdisposable blades504 is illustrated inFIG. 8A, while thereamer500′ shown inFIGS. 8B and 8C includes only tworeamer blades504. Referring toFIG. 80, the guidingpin502 can be spring biased to provide a tactile feedback during reaming. A spring or other biasingelement510 can be constrained between aproximal end512 of the guidingpin502 and awall514 of the supportingshaft506. A set screw orfastener516 can be used to stabilize the guidingpin502 while allowing slidable movement along the alignment axis during reaming. Thespring510 can surround thefastener516, as shown inFIG. 8C. Specifically, thefastener516 is threaded to ablind bore503 of the guidingpin502 such that thefastener516 and the guiding pin can move together along the alignment axis A by or against the action of thespring510. The embodiments ofFIGS. 8B and 80 also include abase ring518 integrally attached to theshaft506 providing additional stability.
• Referring toFIG. 9, after theacetabulum82 has been reamed, anacetabular inserter550 can be coupled to anacetabular cup280 by anend coupler552 at the distal end of ashaft554 of theacetabular inserter550. As seen inFIG. 9, theshaft554 can be slidably and removably coupled or engaged to theengagement surface434 of theconnector432 of thesupport device400, such that the shaft is oriented and can slide along the alignment axis A for insertion of theacetabular cup280 according to the preoperatively planned position and orientation. In some embodiments, theacetabular inserter550 can include animpact head520 and can be used to impact theacetabular cup280 after implantation.
• Referring toFIGS. 10-13, another method of reaming and preparing theacetabulum82 is illustrated using the acetabular guides200 withfitment options200A and200B, as described above in connection withFIGS. 4 and 5. In this method, markers pins260 are inserted through the correspondingbores252 of themarker elements250 and attached to the bone in locations and orientations parallel to an axis B, as determined during the preoperative plan. The marker pins260 can guide the location of asecondary guide600, shown inFIG. 13, and designed according to the pre-operative plan to be guided by the marker pins260, as discussed below.
• Theacetabular guide200 can be slidably lifted off the marker pins260 and removed, leaving the marker pins260 attached to the bone. Theacetabular cup280 can be inserted using anacetabular inserter550 without the aid of an alignment orientation, although asupport device400 with analignment rod402 can also be used if desired.
• If desired, areamer500,500 with a guidingpin502 can be used to ream theacetabulum82, as discussed above in connection withFIG. 7, although other commercially available reamers can also be used. As was described above in connection withFIG. 7 and the acetabular guides100, apilot hole89 of predetermined length is drilled into the acetabulum82 through the guidingelement204 with adrill element440 until thestop442 of the drilling element reaches the upper surface of the guidingelement204 of theacetabular guide200.
• After theacetabular cup280 is inserted but not impacted, asecondary guide600 havingsecondary marker elements650 withbores652 complementarily corresponding to the orientation and relative location of themarker elements250 of theacetabular guide200 is placed over the marker pins260. Thesecondary guide600 can be designed during the pre-operative plan such that thebores652 are complementary to the location and orientation of themarker elements250 of the acetabular guide. Thesecondary guide600 can includeextender elements604 supporting an arcuate or crescent-shapedplanar flange602 having parallel inferior andsuperior surfaces608,610 designed during the pre-operative plan to be oriented parallel to arim282 of theacetabular cup280, when theacetabular cup280 is positioned in the predetermined position and orientation. The orientation and position of theacetabular cup280 is adjusted using thesecondary guide600, such that the planar flange602 (and the inferior andsuperior surfaces608,610 of the planar flange602) and therim282 are parallel by ascertaining contact and engagement of theplanar flange602 to therim282 of theacetabular cup280 in situ. It is noted that this method does not make use of thesupport device400, although the acetabular guides200 can also be used with the supporting device, at the discretion of the surgeon. Depending on the surgeons preferences, any selected or all the acetabular guides100 (110A,100B,1000) and200 (200A,200B) and the associated instruments including thereamer500,500′, the supportingdevice400, thedrilling element440 with thestop442,alignment rod402, marker pins260 and thesecondary guide600 can be provided in a surgical kit together with theacetabular cup280 and/or additional implants and instruments.
• Referring toFIG. 14, another embodiment of thesupport device400 issupport device700 illustrated with a guidinghandle300′ and anacetabular guide100 for positioning analignment rod402 in the pre-planned orientation A′. Thesupport device700 can be attached to the bone withbone pins703 that pass througharms705. Thearms705 extend slidably from abody707 and can includescale markings709 for measuring distances from thebody707. Thebody707 can include aplanar slot711 through which a firstplanar flange713 can slidably pass there through and locked with a fastener (not shown) after adjustment. The firstplanar flange713 includesarms715 pivotably connected to a secondplanar flange717 along a pivot axis coinciding with a center axis of alocking element719. The lockingelement719 can be used to lock the relative orientations of the first and secondplanar flanges713,717. The secondplanar flange717 can have acurved engagement surface721 for slidably engaging ashaft304′ of the guidinghandle300′. The shaft404′ can include agroove303 that is rotationally keyed to anelement721 extending from the secondplanar flange717. Thesupport device700 can provide pivotable and translational adjustability to align thealignment rod402 parallel to the alignment axis A which is fixed when theshaft304′ is attached to the guidingelement104 of the acetabular guide. Thesupport device700 can be used generally similarly to thesupport device400 to provide a reference axis A′ along the reference oralignment rod402 to guide areamer500 orimplant inserter550.
• Referring toFIG. 15, anotherembodiment200C of a patient-specific acetabular guide200 is illustrated. Similarly to the embodiments illustrated inFIGS. 4 and 5 discussed above, theacetabular guide200C includes a patient-specific body202 and a guiding orpilot element204 having anelongated bore206 with an alignment axis A configured to be central to the acetabular cup and perpendicular to the acetabular cup's surface when theacetabular guide200 is positioned on theacetabulum82. Theacetabular guide200 can include one or more marker elements250 (two are shorn), each having anelongated bore252 for guiding corresponding marker pins260. The marker pins260 can be used for supporting a secondary guide such as discussed below in reference toFIG. 12 above, or a secondary guide shown inFIG. 16.
• The patientspecific body202 ofacetabular guide2000 is similar to thebody202 of theacetabular guide200A or200B ofFIGS. 4 and 5, and includes afirst portion202afrom which the guiding element extends and which is designed to engage theacetabulum82, and asecond portion202bwhich extends from theinner portion202aand is configured to extend over arim portion84 of theacetabulum82. Theouter portion202bextends sufficiently beyond therim84 to the periacetabular area of pelvis to accommodate themarker elements250. The patientspecific body202 has an underside or bone-engaging three-dimensional engagement surface208 that is custom-made or patient-specific to conform to and mirror (as a negative or inverse or mirror surface) complementary surfaces of selected portions of theacetabulum82. In the embodiment ofFIG. 15, the patientspecific body202 includes additionally a third portion202cwhich conforms to and covers at least a portion of theacetabular fossa85 of the acetabulum for providing additional rotational stability. Further, aninferior edge203 of theacetabular guide2000 on the third portion202cis designed during the preoperative plan to be parallel to the shape of thetransverse acetabular ligament83. Theinferior edge203 can provide an additional visual confirmation of correct alignment during positioning of theacetabular guide200C on theacetabulum82 of the patient.
• Referring toFIG. 16, another embodiment of asecondary guide600A is illustrated. Thesecondary guide600A can be used with any of the acetabular guides200 (200A,200B,2000). Thesecondary guide600A can have first and second (secondary)marker elements650 withbores652. Thesecondary guide600 can be designed during the pre-operative plan such that thebores652 are complementary to the location and orientation of themarker elements250 of the acetabular guide. The marker pins260 are secured into the bone through themarker elements250 of theacetabular guide200, as shown, for example, inFIG. 10, and discussed above. Theacetabular guide200 is then lifted off the marker pins260 and thesecondary guide600A is guided and placed over the marker pins260. Thesecondary guide600A is also designed during the preoperative plan for the patient to have a guidingelement670 with alongitudinal bore672 along an axis A′ that is parallel to the alignment axis A for the acetabular implant, when thesecondary guide600A is seated on the acetabulum over the marker pins260, as shown inFIG. 16. Accordingly, analignment pin402 inserted into thebore672 can serve as an indicator of the alignment direction A for reaming the acetabulum and inserting the acetabular cup.
• As discussed above, the alignment axis A is the pre-operatively planned axis for insertion of theacetabular cup280. Although the alignment axis A is shown, for simplicity, to coincide with the center axis of various instruments used for inserting, reaming and impacting theacetabular cup280, it should be appreciated that this designation is adapted to indicate the final positioning of the instrument in the desired alignment. In other words, the alignment axis A and the axis of the instrument used are brought to coincidence by the methods described herein and according to the present teachings.
• In some embodiments of the secondary guide, such as thesecondary guide600B shown inFIG. 17, the guidingelement670 may be placed in an offset position relative to thesecondary marker elements650 to provide better visualization of the acetabulum while guiding a reamer, inserter, impactor or other instrument along the alignment axis A parallel to thealignment pin402.
• Referring toFIGS. 18-20B, theacetabular inserter550 coupled to theacetabular cup280 can be guided along the alignment axis A by thealignment pin402 of thesecondary guide600A (or the offsetsecondary guide600B), as an alternate method that does not use thesupport device400 described above and shown inFIG. 9. In some embodiments, anadaptor680, shown inFIGS. 19-20B, can be optionally used to couple theacetabular inserter550 to thealignment pin402 of thesecondary guide600A, as a further aid to orient theacetabular inserter550 along the alignment axis A. In particular, theadaptor680 includes anarm682, such as a cannulated shaft having alongitudinal bore684 that receives thealignment pin402 when theadaptor680 is placed over thealignment pin402. Accordingly, theshaft682 is aligned along the axis A′ that is defined by the guidingelement670 of thesecondary guide600A. The adaptor is coupled to arotatable collar560 of theacetabular inserter550 and secures theacetabular inserter550 along the alignment axis A parallel to the axis A′ of theshaft682 andalignment pin402. Theadaptor680 can be coupled to thecollar560 with a tongue-in-groove or other keyed connection, as illustrated inFIGS. 20A and 20B. In some embodiments, for example, thecollar560 can include anextension562 forming a keyhole-shapedopening565 with afirst portion564 having a circular cross-section and asecond portion566 having an elongated cross-section. Thekeyhole opening565 receives correspondingly shaped portions of theadaptor680, forming a key685 for thekeyhole opening565 and preventing rotational movement. The key685 has a firstcylindrical element686 received in thefirst portion564 of theopening565 and asecond element688 extending at a right angle from thefirst element686 and received into thesecond portion566 of thekeyhole opening565. Additionally, the key685 and thekeyhole opening565 are angled at an acute angle relative to the alignment axis A and axis A′. Specifically, thefirst portion564 of thekeyhole opening565 and thefirst element686 of the key685 are oriented along the direction of an axis C forming an acute angle β with axes A and A′ as shown inFIGS. 20A and 20B. This skewed orientation facilitates the insertion of the key685 into thekeyhole opening565 and the coupling of theadaptor680 to theacetabular inserter550.
• Referring toFIG. 21, in someembodiments680A, the arm of682 of theadaptor680A can include an external V-shapednotch690 instead of aninternal cannulation684 of theembodiment680 ofFIGS. 20A and 20B, while retaining the key685 for engagement with the keyhole opening565 of theacetabular inserter550. Thenotch690 can receive thealignment pin402 in a semi-constrained arrangement for facilitating engagement and disengagement between theadaptor680A and thealignment pin402.
• Referring toFIGS. 22-29, various methods for preparing the acetabulum for receiving an implant will be discussed in connection with the use of electronic positioners (800,900) or other orientation devices for guiding the surgeon along the alignment axis A during reaming and/or inserting and impacting the acetabular implant into the acetabulum. Any commercially available orientation sensing devices can be used for the electronic positioner800 (FIG. 22) or electronic positioner900 (FIGS. 28 and 29). Various embodiments of theelectronic positioner900 are described in commonly assigned patent publications 2010/0249657, and 2010/0249796, both published on Sep. 30, 2010, and incorporated herein by reference. The electronic positioners can include a number of gyroscopic sensors and/or accelerometers that can measure deviations from a predetermined orientation and maintain or guide a return to that orientation. In the context of the present teachings, the predetermined orientation is the alignment axis A that was discussed above. Further, digital or MEMS gyroscopes of small size and capable of measuring deviation about two or three sin axes can be used, such as, for example, a three-axis, single sensor digital gyroscope (model L3G4200D) available from STMicroelectronics, Carrollton, Tex. It should be appreciated, however, that any combination of orientation sensors capable of identifying an orientation in three-dimensional space, including combinations of gyroscopic sensors (digital, analog, fiber optic or other type), having one or more axes, with other orientation sensors, such as accelerometers, such that the combination can identify deviations from an axis in three-dimensional space. For example, a 3-axis gyroscope (yaw, roll and pitch), or three one-axis gyroscopes, or one 2-axis gyroscope and one accelerometers, or three accelerometers or other combinations of gyroscopes and accelerometers. In some embodiments, the accelerometers can be single or multiple axes accelerometers. Mechanical, piezoelectric, MEMS, analog or digital accelerometers and gyroscope can be used. Additionally, a miniaturized compass, a laser, and/or GPS device may be included with the electronic positioner.
• Referring toFIG. 22, theelectronic positioner800 can include ahousing802 that is removably attachable to a shaft of an inserter, impactor, reamer or other instrument used in connection with the acetabular arthroplasty or other corrective procedure. InFIG. 22, the electronic positioner is shown coupled to theacetabular inserter550. Theelectronic positioner800 can be, for example, keyed to theshaft554, slidably attached to theshaft554 or thecollar560 of theacetabular inserter800 or slip-fit or with a clamp-on or tongue-and-groove or other coupling arrangement. Thehousing802 can include a controller/processor communicably coupled to the orientation sensor/sensors discussed above, and a feedback module. An exemplary block diagram for theelectronic positioner900 ofFIG. 20 is shown inFIG. 29, described below, and can be used for theelectronic positioner800, although the impact sensor and associated modules are optional and can be omitted from the electronic positioner of800.
• Theelectronic positioner800 can include a power or on/offbutton806, a set button/input device808 for setting a pre-determined orientation during calibration and a set of LEDs804 (outer set804) for guiding theshaft554 along the predetermined orientation (i.e., the alignment axis A) by lighting up to indicate a direction. Theelectronic positioner800 can also include anoptional laser device810 capable of providing areference orientation812. Thelaser device810 may be used, for example, with accelerometers that measure in two non parallel directions in a plane perpendicular to thereference orientation812 of the laser. Theelectronic positioner800 can be calibrated using one of the patient-specific acetabular guides described above, such as, for example, theacetabular guide200C, shown inFIG. 22. Theacetabular guide2000 can be positioned at a unique position on the patient's acetabulum, such that the guidingelement204 defines the alignment axis A, as designed during the preoperative plan. Theshaft554 of theacetabular inserter550 can be slidably coupled to the guidingelement204 as described above in reference toFIG. 6, for example, such that the longitudinal axis of theshaft554 coincides with the alignment axis A.
• With theshaft554 of theinserter550 aligned along the alignment axis A, and theelectronic positioner800 coupled thereon, the set button/input device808 can be pressed or otherwise activated to set or identify the alignment axis A as a reference axis, and store its orientation. As theshaft554 is moved, deviations from the reference axis can be calculated by the sensors (see934,FIG. 29) of the electronic positioner, processed by the controller (see946,FIG. 29) of the electronic positioner and feedback provided by theLEDs804 indicating the direction and increment of deviation. For example, the direction of deviation or, alternatively the direction to move to correct the deviation, can be indicated by the direction defined by a lit LED, such as, for example,804brelative to acentral LED804a, which lights up when theshaft554 is correctly aligned along the reference/alignment axis A. In some embodiments, a relative amount or degree of deviation for a given direction of a deviation can be indicated by a change in color of theLEDs804, or by another set of LEDs803 (inner set) that light up at a different fixed color, for example a fixed yellow to a fixed red of the outer set ofLEDS804. It will be appreciated that other types of feedback mechanisms or arrangements with or without LEDS and including visual, audio and vibratory or tactile feedback can be used, as disclosed in patent publications 2010/0249657 and 2010/0249796, referenced above, and further discussed below in reference toFIGS. 28 and 29.
• After theelectronic positioner800 is calibrated, the surgeon may ream the acetabulum82 using a surgeon-selected method or any of the methods discussed above. See, for example,FIG. 8A and associated discussion.FIGS. 23A and 23B illustrate the patient'sacetabulum82 before and after reaming, respectively. After reaming, theacetabular inserter500 with theelectronic positioner800 thereon can be coupled to theacetabular implant280, as shown inFIG. 24, for inserting theacetabular implant280 along the predetermined alignment axis A, as guided by theelectronic positioner800. Feedback from theLEDs804 and/or803 or other feedback mechanism can help guide the surgeon to correct any deviation from the predetermined alignment axis A that coincides with the calibrated reference axis of theelectronic positioner800, as discussed above.
• When using theelectronic positioner800, as described above, marker pins260 and asecondary guide600,600A,600B are not necessary. Depending on the surgeon's preference, when additional guidance is desired, the marker pins260 and thesecondary guide600A (or600 or600B) can be used together with theelectronic positioner800, as illustrated inFIGS. 25-27. The marker pins260 can be inserted, for example, through themarker elements250 of the patient-specific acetabular guide200C, as shown inFIG. 25 during calibration of theelectronic positioner800. After calibration, the patient-specific acetabular guide2000 is lifted off the marker pins260, which are left attached to theacetabulum82 for guiding the placement of thesecondary guide600A (or600B or600), as shown inFIG. 26A. Thealignment pin402 can be used as a reference for the implant alignment axis A. In some embodiments, thealignment pin402 can be used to align a supportingshaft506 of a reamer500 (seeFIG. 8A) parallel to the direction A′ of thealignment pin402 and used during reaming. After reaming, thesecondary guide600A and the marker pins260 can remain attached to the acetabulum, as shown inFIG. 26B, to further guide the surgeon during the insertion of theacetabular cup280. Accordingly, and referring toFIG. 27, thealignment pin402 of thesecondary guide600A can provide an initial reference direction A′ for the surgeon to position theacetabular inserter800 easier and quicker along the alignment direction A, and make smaller corrections in orientation with the help of theLEDs804,803 or other feedback mechanism of theelectronic positioner800.
• Referring toFIGS. 28 and 29, theelectronic positioner900 of the above referenced patent publications 2010/0249657 and 2010/0249796 is briefly described. It will be appreciated that in some embodiments, theelectronic positioner900 can replace theelectronic positioner800 in the methods described above. In other embodiments, theelectronic positioner800 can incorporate all or some of the functions of theelectronic positioner900, while maintaining, for example, the geometry of thehousing802 and the LED feedback arrangement described above in reference toFIG. 22. In some embodiments, theelectronic positioner800 can include a orientation sensor (or sensors)934, but not impactsensors947 and impact feedback, as discussed below. In other embodiments, theelectronic positioner800 may also include theimpact sensor947 and associated feedback mechanisms of theelectronic positioner900.
• As shown inFIGS. 28 and 29, theelectronic positioner900 can include acylindrical housing926 coupled to an acetabular inserter/impactor tool916 having alongitudinal shaft918. Specifically, thehousing926 can include apassage930 that receives theshaft918 and couples thehousing926 to the acetabular inserter/impactor tool916 in a fixed position relative to theshaft918. Thehousing926 can include a seam or hinge or otherlongitudinal separator931 between first andseconds portions932a,932bof thehousing926 for removing thehousing926 from theshaft918. In some embodiments, thehinge931 can operate to secure the first andsecond portions932a,932bin a clam shell design of thehousing926.
• It will be appreciated that thehousing926 can be attached to theshaft918 in any suitable fashion, such as an interference fit, a taper to taper fit between theshaft918 and the inner surface of thepassage930, or other arrangement. In some embodiments, theshaft918 can include a recess (not shown) that receives thehousing926 such that thehousing926 is in a fixed position relative to theshaft918. Further, theelectronic positioner900 can be removably coupled to various commercially available inserter/impactor tools916, such as a RingLoc® Inserter (Part No. S313141) or a Magnum Inserter (Part No. 313131), commercially available from Biomet Manufacturing Corp., of Warsaw, Ind. Theelectronic positioner900 can be similarly coupled to the shaft of theinserter550 orreamer500 or guidinghandle300 or other tool used during the acetabular procedure for guiding along the alignment axis A.
• As shown inFIGS. 28 and 29, theelectronic positioner900 can include one ormore orientation sensors934. Theorientation sensor934 can detect an actual orientation of the longitudinal axis of the inserter/impactor tool916 relative to a reference orientation or reference vector, such as the force of gravity. In some embodiments, theorientation sensor934 can detect acceleration about three separate orthogonal axes (accelerometer sensors) or angular velocity (spin) about one or more orthogonal axes (gyroscopic sensor), as discussed above in reference to theelectronic positioner800.
• The electronic positioner900 (or800) can include anorientation feedback device936. Theorientation feedback device936 can selectively provide an orientation feedback signal when the actual orientation of the inserter/impactor tool916 is substantially equal to a predetermined target orientation, i.e., the alignment axis A discussed above. The feedback signal provided by theorientation feedback device936 can automatically indicate to the surgeon that the inserter/impactor tool916 is in the target orientation, such that the acetabular cup can be properly positioned and implanted for added convenience and accuracy.
• As represented inFIG. 29, theorientation feedback device936 can include anaudible feedback device938 that emits an audible feedback signal. For instance, theaudible feedback device938 can include a speaker that emits a preprogrammed sound when the inserter/impactor tool916 is in the target orientation. Furthermore, theorientation feedback device936 can include avisual feedback device940 that emits a visual feedback signal. For instance, thevisual feedback device940 can include one or more lights, such as LED lights, for emitting a preprogrammed light pattern when the inserter/impactor tool916 is in the target orientation. An embodiment of thevisual feedback device940 is described above in connection with theLEDs804 and803 of theelectronic positioner800. Additionally, theorientation feedback device936 can include a tactile feedback device that selectively emits a tactile feedback signal when the inserter/impactor tool916 is in the target orientation. For instance, thetactile feedback device942 can include a vibration motor that selectively vibrates thehousing926 and the inserter/impactor tool916 when the inserter/impactor tool916 is in the target orientation.
• It will be appreciated that theorientation feedback device936 can provide any suitable feedback signal, including combinations of visual, audible and tactile feedback. Also, it will be appreciated that the feedback signal can be seen, heard, and felt simultaneously, and this redundancy can increase accuracy and convenience.
• The electronic positioner900 (or800) can include acontroller946. Thecontroller946 can include various components, such as a microprocessor, memory, and the like. Thecontroller946 can be in communication with theorientation sensor934 and theorientation feedback device936. Accordingly, thecontroller946 can cause theorientation feedback device936 to selectively provide the respective orientation feedback signal(s) when the actual orientation of the inserter/impactor tool916 detected by theorientation sensor934 is substantially equal to a predetermined target orientation of the inserter/impactor tool916.
• The electronic positioner900 (or800) can include animpact sensor947 to help the surgeon determine more accurately and conveniently when theacetabular cup280 is fully seated in theacetabulum82 of the patient. Theimpact sensor947 can detect an actual impact effect on the inserter/impactor tool916. For instance, theimpact sensor947 can be configured to detect an actual impact force F_ion thehead920 of the inserter/impactor tool916. Theimpact sensor947 can also detect an actual displacement of the inserter/impactor tool916 when the load F_iis applied to thehead920. In addition, theimpact sensor947 can detect an actual acoustic effect of the impact when the load F_iis applied. It will be appreciated that theimpact sensor947 can be configured to detect any suitable effect of applying the load F_i. Theimpact sensor947 can include any suitable component, such as an accelerometer and/or a piezoelectric sensor, for detecting the actual impact effect. It will be appreciated that theorientation sensor934 and theimpact sensor947 can rely, at least in part, on some of the same components, such as a common accelerometer, for the respective functions.
• With continued reference toFIGS. 28 and 29, the electronic positioner900 (or800) can include animpact feedback device948. Generally, theimpact feedback device948 can provide a feedback signal when the actual effect of applying the load F_idetected by theimpact sensor947 substantially matches a predetermined target impact effect. More specifically, the surgeon can predetermine a target impact effect (e.g., a predetermined impact force F_i, an amount of displacement, an acoustic effect, etc.) that correlates to a condition in which theacetabular cup280 is fully seated in theacetabulum82 of the patient. Then, thecontroller946 can cause theimpact feedback device948 to provide the respective feedback signal when the actual impact effect substantially matches the predetermined target impact effect. Thus, theimpact feedback device948 can inform the surgeon that theacetabular cup280 has been fully seated into theacetabulum82 of the patient.
• It will be appreciated that theimpact feedback device948 can include any suitable device, such as anaudible feedback device950, avisual feedback device952, and/or atactile feedback device954. Theaudible feedback device950 can provide an audible feedback signal, and can include a speaker or any other suitable device for providing an audible feedback signal. Thevisual feedback device952 can provide a visual feedback signal, and can include one or more lights, such as LED lights, for providing a visual feedback signal. Also, thetactile feedback device954 can provide a tactile feedback signal and can include a vibration motor that selectively provides a tactile feedback signal.
• In some embodiments, the electronic positioner900 (or800) can include aninput device941 for manually setting the target orientation of the inserter/impactor tool916. More specifically, theinput device941 can include buttons, dials, a display, and other features for setting a target inclination angle, a target anteversion angle, or any other setting for the orientation of the alignment axis A. The input device41 can be integrally coupled to thehousing926, and/or theinput device941 can be separate and remote from thehousing926. For example, as shown inFIG. 28, theinput device941 can include awireless transmitter943, and thehousing926 can include awireless receiver945. Thereceiver945 receives wireless signals from thetransmitter943 to thereby set the target orientation of the alignment axis A. In some embodiments, theinput device941 can include an alphanumeric keypad for manually inputting and setting a particular target orientation. Additional details about of theelectronic positioner900 can be found in patent publications 2010/0249657 and 2010/0249796, referenced above, and are or can be similarly incorporated in theelectronic positioner800.
• Various patient-specific guides, secondary guides, reamers, guide handles, inserters, impactors, support devices, electronic positioners and other instruments can be used in various combinations and based on surgeon preferences or patient and preoperative or intraoperative circumstances for preparing an acetabulum and guiding and implanting an acetabular implant along a preoperatively determined alignment orientation. In this respect, tools and instrumentation providing redundant functionality and of different embodiments may provided to the surgeon in a kit or per surgeon's request. For example, more than one patient specific acetabular guide (100,200) may be provided. Similarly, various support devices (400,700), secondary guides (600,600A,600B), reamers (500,500′), inserters and/or impactors (550,916), adaptors or couplers, electronic positioners (800,900) and other instruments described above can be provided and used in various combinations within the scope of the methods described herein.
• The foregoing discussion discloses and describes merely exemplary arrangements of the present teachings. Furthermore, the mixing and matching of features, elements and/or functions between various embodiments is expressly contemplated herein, so that one of ordinary skill in the art would appreciate from this disclosure that features, elements and/or functions of one embodiment may be incorporated into another embodiment as appropriate, unless described otherwise above. Moreover, many modifications may be made to adapt a particular situation or material to the present teachings without departing from the essential scope thereof. One skilled in the art will readily recognize from such discussion, and from the accompanying drawings and claims, that various changes, modifications and variations can be made therein without departing from the spirit and scope of the present teachings as defined in the following claims.

Claims (1)

What is claimed is:

1. A method for reaming and preparing an acetabulum of a patient for an acetabular implant, the method comprising:

engaging an acetabular area of the patient with a complementary surface of a patient-specific acetabular guide;

supporting an alignment rod on a support device attached to the patient's pelvis;

orienting the alignment rod to be parallel to an alignment axis for inserting the acetabular implant, the alignment axis determined during a preoperative plan of the patient and coinciding with a center axis of a guiding element of the acetabular guide;

drilling a pilot hole in the acetabulum through a bore of the guiding element along the center axis;

removing the acetabular guide;

guiding an alignment pin of a reamer in the pilot hole such that the alignment pin is parallel to the alignment rod; and

reaming the acetabulum.

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