Assembly and kit for reaming an orthopaedic joint and method of assembling a reamer for said use

Abstract

A system for reaming a bone, comprising: a base comprising a connector adapted to couple the base to a driver and a support surface; a first reaming member comprising: a first seating surface shaped to seat the first reaming member over the support surface; a first reaming surface adapted to ream a bone to a first diameter; and a first attachment mechanism attaching the first reaming member to the base; a second reaming member comprising: a second seating surface shaped to seat the second reaming member over the support surface; a second reaming surface adapted to ream a bone to a second diameter; and a second attachment mechanism attaching the second reaming member to the base; wherein the second diameter is greater than the first diameter.

Description

TECHNICAL FIELD

[0001] The present invention relates to an assembly for reaming an orthopaedic joint, a kit for reaming an orthopaedic joint, a method of assembling a reamer for reaming an orthopaedic joint, and a method of preparing a reamer for use in an orthopaedic joint procedure. BACKGROUND

[0002] Human and animal bodies have various joints, such as ankles, knees, hips, shoulders, and elbows. Joints are formed at the intersection of two or more skeletal bones. Many joints allow movement between the two or more bones. Between body joints that allow motion, cartilage is typically found.

[0003] Cartilage provides lubrication for movement and absorbs some of the forces experienced by the joint. Cartilage can wear over time, causing the bones that make up the joint to come into contact with each other, resulting in pain and decreased joint function.

[0004] Another cause of joint damage is arthrosis. Arthrosis, such as arthritis, is a disease of the joint that can cause conditions such as pain, stiffness, and swelling.

[0005] The hip joint is one of the joints that can experience degeneration or disease. The hip joint is a ball-and-socket arrangement formed at the intersection of the femoral head of the femur and the acetabulum of the pelvis. The femoral head, as the ball of the joint, and the acetabulum, as the socket of the joint, are covered with cartilage to allow articulation of the femur relative to the pelvis. Other commonly affected joints include those of the spine, knee, shoulder, elbow, carpus, metacarpus, and phalanges of the hand.

[0006] One option to treat a damaged joint is to replace the degenerated or diseased portion of the joint with a prosthesis. A commonly used prosthesis is a total joint prosthesis. A total joint prosthesis is used to replace a natural joint part or natural joint portion with an artificial joint. For example, in a total hip replacement procedure, a natural hip joint can be treated with a total hip replacement prosthesis. The total hip replacement prosthesis includes an artificial femoral portion and an artificial acetabular portion.

[0007] During a surgical procedure to replace a joint, the joint is prepared to receive its corresponding portion using specialized instruments. One such instrument is a reamer. A reamer is an instrument used to remove the portion of the bone to be replaced and can be used to shape the bone to receive the appropriate prosthetic component.

[0008] In a total hip arthroplasty, a reamer can be used to prepare the acetabulum of a recipient to receive a replacement cup prosthesis. Acetabular reamers are typically hemispherical and are used to prepare a correspondingly shaped cavity in the acetabulum.

[0009] To prepare the cavity, a reamer can be connected to a power tool that is used to rotate the reamer. The rotating reamer engages the acetabulum and prepares the hemi-spherical cavity.

[0010] The diameter of the reamed cavity is determined by the size of the replacement cup prosthesis to be implanted.

[0011] For a hip replacement procedure, the diameter of the reamed cavity of the acetabulum can be planned. To reach the planned diameter, the physician can begin preparing the acetabulum with a reamer having a smaller diameter than the planned diameter. The physician can incrementally increase to the planned diameter using reamers of increasing diameter. In a typical procedure, a smaller diameter reamer will be removed and replaced with a larger diameter reamer. The physician will then engage the larger diameter reamer with the acetabulum to ream the cavity to the larger diameter.

[0012] Known reamers include those disclosed in various patents and patent applications. For example, PCT Publication No. WO 2007 / 097749 Al discloses a disposable acetabular reamer and method of making the same. The disclosed disposable acetabular reamer has cutter blades molded into the surface of a support. The cutter blades are formed from a single flat sheet of metal material having a series of teeth formed thereon that protrude above the surface of the support such that when the acetabular reamer is rotated, the teeth contact the surface of the acetabulum to ream the bone.

[0013] Another known reamer is disclosed in U.S. Patent Application Serial No. 14 / 746,386, published as U.S. Publication No. US 2015 / 0366568 Al. The disclosed disposable cutter acetabular reamer includes a support frame having a plurality of radially extending struts to which a cutting housing is removably connected. The frame serves as a universal support structure that provides increased mechanical support and stability to which various embodiments of the cutting housing can be connected to remove bone and tissue.

[0014] Yet another known reamer is disclosed in U.S. Patent Application Serial No. 13 / 741,211, now U.S. Patent No. 9,101,368. The disclosed reamer has a cutting tool having a cutting surface on a first side of the cutting tool and an attachment member on a second side of the cutting tool. The cutting surface can have a cutting edge having varying properties along the cutting tool.

[0015] Yet another known reamer is disclosed in U.S. Patent Application No. 858,934 (now U.S. Patent No. 5,299,893). The disclosed reamer is a disposable cutter having a plurality of cutting edges. The cutter has a bore adjacent the cutting edges. The cutter defines an axis of rotation. The cutter is engaged to a transparent bowl. The bowl is concentric with the axis of rotation. The bowl has a bottom tool driver opening concentric with the axis of rotation. SUMMARY

[0016] According to a first aspect of the present invention, an assembly is provided. The assembly includes a base, a first reaming member, and a second reaming member. The base has a connector adapted to couple the base to a driver and a support surface. The first reaming member includes a first seating surface shaped to seat the first reaming member above the support surface. The first reaming member includes a first reaming surface adapted to ream bone to a first diameter. The first reaming member includes a first attachment mechanism to attach the first reaming member to the base. The second reaming member includes a second seating surface shaped to seat the second reaming member above the first reaming surface. The second reaming member includes a second reaming surface adapted to ream bone to a second diameter. The second reaming member includes a second attachment mechanism to attach the second reaming member to the base. The second diameter is greater than the first diameter.

[0017] Preferably, the first reaming member and the second reaming member can be releasably attached to the base.

[0018] Preferably, the second reaming surface can be separated from the first reaming surface by a predetermined thickness, thereby increasing the second diameter relative to the first diameter.

[0019] Preferably, the support surface can have an outer shape and the first seating surface has an inner shape that matches the outer shape. The outer shape can be hemispherical and the inner surface has a curvature that conforms to the outer shape.

[0020] Preferably, the base can have a first recess extending into the support surface. The first reaming member can have a first prong and a second recess. The second reaming member can have a second prong. The first recess can be configured to receive the first prong to attach the first reaming member to the base. The second recess can be configured to receive the second prong to attach the second reaming member to the base.

[0021] Preferably, the second reaming member can be positioned above the first reaming member and attached to the first reaming member by the second attachment mechanism in order to attach the second reaming member to the base. Preferably, the base can include a base coupling, the first attachment mechanism and the second attachment mechanism being couplable to the base coupling. Preferably, the first attachment mechanism and the second attachment mechanism are independently couplable to the base coupling.

[0022] According to a second aspect of the application, there is provided a kit having a base, a first reaming member, and a second reaming member. The base can have a connector adapted to couple the base to a driver and a support surface. The first reaming member can have a first seating surface, a first reaming surface, and a first attachment mechanism. The first seating surface can be shaped to seat the first reaming member above the support surface. The first reaming surface can be adapted to ream bone to a first diameter. The first attachment mechanism can be configurable to attach the first reaming member to the base. The second reaming member can have a second seating surface, a second reaming surface, and a second attachment mechanism. The second seating surface can be shaped to seat the second reaming member above the first reaming surface. The second reaming surface can be adapted to ream bone to a second diameter. The second attachment mechanism can be configurable to attach the second reaming member to the base. The second diameter can be greater than the first diameter.

[0023] According to a third aspect of the application, there is provided a method of assembling a reaming drill. The method can comprise the steps of:

[0024] providing a base, the base including a connector adapted to couple the base to a driver and an outer surface defining a support surface;

[0025] providing a first reaming member, the first reaming member having:

[0026] a first inner surface shaped to seat the first reaming member on the support surface; a first outer surface adapted to ream bone; and

[0027] a first attachment mechanism attaching the first reaming member to the base;

[0028] engaging the first inner surface with the support surface;

[0029] attaching the first reaming member to the base with the first attachment mechanism;

[0030] providing a second reaming member, the second reaming member having:

[0031] a second inner surface shaped to seat the second reaming member on the first outer surface;

[0032] a second outer surface adapted to ream bone;

[0033] a second attachment mechanism configurable to attach the second reaming member to the

[0034] a base;

[0035] engaging the second inner surface with the first outer surface; and

[0036] attaching the second reaming member to the base with the second attachment mechanism.

[0037] According to a fourth aspect of the application, there is provided a surgical method. The method can comprise the steps of:

[0038] providing a base comprising a connector adapted to couple the base to a driver and an outer surface defining a support surface;

[0039] providing a first reaming member having:

[0040] a first inner surface shaped to seat the first reaming member on the support surface; a first outer surface adapted to ream bone to a first diameter;

[0041] a first diameter; and

[0042] a first attachment mechanism attaching the first reaming member to the base;

[0043] engaging the first inner surface with the support surface;

[0044] attaching the first reaming member to the base with the first attachment mechanism;

[0045] reaming bone to the first diameter;

[0046] providing a second reaming member having:

[0047] a second inner surface shaped to seat the second reaming member

[0048] on the first outer surface;

[0049] a second outer surface adapted to ream bone to a second diameter greater than the first diameter; and

[0050] a second attachment mechanism attaching the second reaming member to the base;

[0051] engaging the second inner surface with the first outer surface;

[0052] attaching the second reaming member to the base with the second attachment; and reaming bone to the second diameter. BRIEF DESCRIPTION OF DRAWINGS

[0053] For a more complete understanding of the present application, and for further

[0054] Figure 1 shows a cross-sectional side view of a reamer assembly of a first embodiment of the present application;

[0055] Figure 2 shows Figure 1 shows an exploded cross-sectional side view of a reamer assembly;

[0056] Figure 3 shows a cross-sectional side view of a reamer assembly of a second embodiment of the present application;

[0057] Figure 4 shows Figure 3 shows an exploded cross-sectional side view of a reamer assembly;

[0058] Figure 5 shows Figure 3 shows an expanded view of portion X showing a coupling for coupling a reaming member to Figure 3 shows a connection feature of a base of a reamer assembly;

[0059] Figure 6 shows Figure 3 shows a perspective view of a base of a reamer assembly;

[0060] Figure 7 shows Figure 3 shows a perspective view of a portion of a reamer assembly;

[0061] Figure 8 shows Figure 3 shows a perspective view of a reamer assembly;

[0062] Figure 9 shows an exploded front view of a reaming assembly of a third embodiment of the present application;

[0063] Figure 10A shows Figure 9 shows a cross-sectional view of a side of a reaming assembly;

[0064] Figure 10B showsFigure 9 a cross-sectional view of another side of the reaming assembly shown;

[0065] Figure 11 a side view of a reaming assembly showing a fourth embodiment of the invention;

[0066] Figure 12 a perspective view of a reamer assembly showing Figure 11 a perspective view of a base of the reaming assembly shown;

[0067] Figure 13 a perspective view of a reamer assembly showing Figure 11 a perspective view of a reamer assembly showing

[0068] Figure 14 a perspective view of a reamer assembly showing Figure 10A and Figure 10B a series of front views of reamer members of different sizes positioned on a base of the reamer assembly shown;

[0069] Figure 15 a perspective view of a reamer assembly showing Figure 10A and Figure 10B an exemplary reamer drill driver of the reamer assembly; and

[0070] Figure 16 another exemplary reamer drill driver is shown. DETAILED DESCRIPTION

[0071] The invention is a reamer drill. A portion of the reamer drill has a generally hemispherical shape shaped to conform to the shape of, for example, a hip joint prosthesis. The exemplary reamer drill is intended to prepare and refine the inner surface of a pelvic acetabular cup known as the acetabulum to receive a cup portion of a hip joint prosthesis.

[0072] The reamer drill includes a base to which a reamer member is coupled. The reamer member includes a cutting feature that is capable of engaging, for example, an acetabulum to remove and prepare bone for receiving a replacement cup.

[0073] The reamer drill includes a plurality of reamer members. A first reamer member of the plurality of reamer members has a first diameter. A second reamer member of the plurality of reamer members has a second diameter that is greater than the first diameter. During a surgical procedure, the first reamer member is coupled to the base and used to ream the acetabulum to the first diameter. Thereafter, the second reamer member is coupled to the base and used to ream the acetabulum to the second, larger diameter.

[0074] The base of the reamer drill is a common base to which each of the plurality of reamer members is coupleable. The base provides a support structure to which the reamer members are coupled.

[0075] The support structure is a common structure that provides support to the first reamer member and each successive reamer member.

[0076] In certain embodiments, a first reaming member having a first outer diameter is positioned above the base. A second reaming member having a second, larger outer diameter is positioned above the first reaming member, and so on, for a third reaming member, a fourth reaming member, a fifth reaming member, etc. In this way, support is provided to each reaming member having an incremental diameter by the nested stack of reaming members already coupled to the base.

[0077] In other embodiments, a first reaming member having a first outer diameter is coupled to the base and used for reaming. The first reaming member is removed from the base and a second reaming member having a second, larger outer diameter is coupled to the base. In this way, support is provided to each reaming member by the base.

[0078] As will be appreciated by those of ordinary skill in the art, other alternative embodiments are certainly possible. However, it will be appreciated that the base is a common base that is capable of reaming coupled to a reamer driver, while reaming members having incremental diameters are coupled to the common base, thereby increasing the efficiency of the procedure of preparing a hemispherical cavity in a bone.

[0079] Figure 1 A first embodiment of the present invention is shown. The first embodiment is a reamer 1 for reaming a bone, such as an acetabulum. The reamer 1 has a base 10 and a plurality of reaming members 25. The plurality of reaming members 25 are capable of being coupled to the base 10 to form an assembly, which is interchangeably referred to herein as the reamer 1 or the reaming assembly 1.

[0080] The base 10 has a connector surface 12 in which a connector 14 is defined. The connector 14 can be configured to receive a conventional reamer coupling, or it can be configured to receive a Figure 15 The coupling 201 of the driver 200 shown, or Figure 16 The coupling 301 of the driver 300 shown. The driver 200 is for applying rotational motion to the reamer 1 in use.

[0081] The base 10 has a support surface 16. The support surface 16 has an outer shape. The outer shape is selected to provide a seating surface that supports the plurality of reaming members 25 in use.

[0082] The connector surface 12 is substantially planar. The connector surface 12 has a circular outer periphery 18. The connector surface 12 has a midpoint Ml. The connector surface 12 has a radius RB measured as a straight line extending from the midpoint Ml to the outer periphery 18 of the connector surface 12.

[0083] Reference is made to Figure 1The shape of the support surface 16 is hemispherical. Of course, this shape is merely exemplary and other support surface shapes are of course possible without departing from the scope of the invention.

[0084] The support surface 16 provides overall support and rigidity to each reaming member 25 arranged on the base. The support surface 16 is a hemispherical dome extending from the outer periphery 18 to the pole 20. The radius of the hemispherical dome is the same as the radius RB of the connector surface. The radius RB is measured as a straight line extending from the midpoint Ml to the outer edge of the support surface 16.

[0085] The pole 20 is located on the axis A. The axis A passes through the midpoint Ml and extends perpendicular to the connector surface 12. The channel 22 extends through the support surface 16 from the pole 20 to the connector surface 12 parallel to the axis A. The channel 22 has a recess 24 in the middle.

[0086] Each reaming member 26 of the plurality of reaming members 25 has a seating surface 28, a reaming surface 30, and an attachment mechanism 32.

[0087] The seating surface 28 is a portion of the reaming member 26 arranged above the underlying support surface.

[0088] The reaming surface 30 is a portion of the reaming member 26 that engages with the acetabulum for preparing the bone to receive the implant. The reaming surface 30 has a cutter 31 arranged to remove bone and other tissue in the process of preparing the bone for receiving the implant.

[0089] The attachment mechanism 32 is a portion of the reaming member 26 that is used to attach the reaming member 26 to the base 10.

[0090] A first reaming member 26 of the plurality of reaming members 25 to be connected to the base 10 is positioned on the support surface 16. Here, the seating surface 28 is positioned on the support surface 16.

[0091] The attachment mechanism 32 is a protrusion extending from a pole 34 of the reaming member 26. The attachment mechanism 32 is arranged to engage with the channel 22. A hook 36 is defined at the end of the protrusion forming the attachment mechanism 32. The hook 36 engages the recess 24 to couple the reaming member to the base 10.

[0092] The channel 22 and the recess 24 in combination with the attachment mechanism 32 form a lock for coupling each reaming member 25 to the base 10.

[0093] Reference is made to Figure 2Each successive reaming member 26A, 26B, 26C, 26D is stacked on top of the reaming member already positioned on the base 10. For example, the first reaming member 26A is positioned on the base 10, the second reaming member 26B is positioned above the first reaming member 26A, and so on, the third reaming member 26C and the fourth reaming member 26D.

[0094] A portion of the first reaming member 26A is positioned on the support surface 16. This portion positioned on the base is the seating surface 28A of the first reaming member 26A. Subsequent reaming members positioned on the reaming assembly 1 are positioned above the reaming surface 30A covering the cutter 31A of the first reaming member 26A. In this way, the reaming surface 30A becomes a support surface on which the seating surface of the subsequent reaming member is seated.

[0095] In Figure 2 In the first embodiment shown, each successive reaming member 26A, 26B, 26C, 26D is positioned above the reaming member previously coupled to the reaming assembly 1. For example, the seating surface 28B of the second reaming member 26B is positioned on the reaming surface 30A of the first reaming member 26A. Each successive reaming member increases the diameter dimension of the reaming assembly 1 by a predetermined amount. The predetermined amount can be in the range of 0.5mm to 2mm. In one preferred embodiment, the predetermined amount is 1mm. With this capability, the reaming assembly 1 can be used to effectively ream a cavity of increasing diameter dimension without the need to remove the reaming assembly 1 from the driving instrument until the operator has reamed the cavity to the desired size.

[0096] Figure 2 The reaming assembly 1 is shown with four reaming members. As will be appreciated by those skilled in the art, any number of reaming members can be positioned above the reaming member already positioned on the base 10 and coupled to the base to form the reaming assembly 1 for reaming a cavity of a desired size.

[0097] In use, the first reaming member 26A is connected to the base 10 to form a reaming drill 1 having a first diameter. The reaming drill 1 is connected to a driver. The reaming drill 1 can be configured to couple to a conventional reaming drill coupling, or it can be configured to receive a coupling of the driver. Figure 15 The coupling 201 of the driver 200 shown, or Figure 16 The coupling 301 of the driver 300 shown.

[0098] The reamer 1 is then engaged with the acetabulum and driven to prepare the acetabulum to a first reaming diameter. The reamer 1 is removed and the acetabulum is visually assessed. If the acetabulum is to be reamed to a wider diameter, a second reaming member 26B is attached to the reamer 1. Since the reamer 1 is already connected to the driver 200, 300, the reamer 1 can be used to ream the cavity to a second, larger reaming diameter. This process is repeated to incrementally ream the diameter until the physician or other operator has determined that the reamed cavity has the desired reaming diameter.

[0099] The base 10 is made of a plastic material. Suitable plastic materials include polyacrylamide. For example, the base 10 can be made in the form of polyacrylamide sold under the trade name IXEF. Of course, the base 10 can be made of other suitable materials.

[0100] The base is made using plastic injection molding. Of course, any other suitable manufacturing technique can be used to manufacture the base 10.

[0101] Each reaming member 26A, 26B, 26C, 26D is made of a metal material. Suitable metals include stainless steel. For example, each reaming member 26A, 26B, 26C, 26D can be made of 17-4PH type stainless steel. Of course, the base 10 can be made of other suitable materials.

[0102] The reaming members 26A, 26B, 26C, 26D are manufactured using metal injection molding. Of course, any other suitable manufacturing technique can be used to manufacture the reamer members 26A, 26B, 26C, 26D.

[0103] Figure 3 A reaming assembly 2 of a second embodiment of the present application is shown. The reaming assembly 2 has a base 60 and a plurality of reaming members 75. The plurality of reaming members 75 are couplable to the base 60 to form the reaming assembly 2. Similar to the first embodiment, the reaming members 75 are stacked on top of each other to form a reamer assembly having an increasing diameter size.

[0104] The base 60 has a connector surface 62 in which a connector 64 is defined. The connector 64 is configured to receive a coupling 201 of a driver. The driver can be a conventional driver, Figure 15 the illustrated driver 200, or Figure 16 the illustrated reamer 300, or any other suitable driver. The driver is used to apply rotational motion to the reamer 2 in use.

[0105] The base 60 has a support surface 66. The support surface 66 has a generally flat surface. The base 60 has an outer periphery 68 that defines a circular edge of the base 60. The connector surface 62 and the support surface 66 are spaced apart by the outer periphery 68.

[0106] A post 69 is located on the support surface 66. The post 69 is a shaft extending from a base where it is located on the support surface 66 to an apex 70. The post 69 is located on an axis B that passes through the midpoint M2 and extends perpendicularly from the connector surface 66.

[0107] A channel 72 extends from the apex 70 towards the support surface 66 parallel to the axis B.

[0108] A channel 73 is located in a central region of the post 69. The channel 73 intersects the channel 72. An opening 74 is formed where the channel 73 intersects the channel 72.

[0109] With reference to Figure 4 Each reaming member 76A, 76B, 76C of the plurality of reaming members 75 has an inner surface 78, an outer reaming surface 80, and an attachment mechanism 82. The reaming surface has a plurality of cutters 81 arranged for preparing bone to receive an implant.

[0110] Each reaming member 76A, 76B, 76C has a hemispherical shape with a pole 84 extending to an equator 85.

[0111] The inner surface 78 is the portion of the reaming member 76A, 76B, 76C facing the support surface 66 when the reaming member 76A, 76B, 76C is arranged on the reaming assembly 2.

[0112] The reaming surface 30 is the portion of the reaming member 76A, 76B, 76C that engages with the acetabulum for preparing bone to receive an implant.

[0113] The attachment mechanism 82 is the portion of the reaming member 76A, 76B, 76C that is used to attach the reaming member 76A, 76B, 76C to the base 60. The attachment mechanism 82 is a protrusion extending from the pole 84 of the reaming member 76A, 76B, 76C. The attachment mechanism 82 is resilient.

[0114] The attachment mechanism 82 is configured to engage the channel 72 to couple the reaming member 76A, 76B, 76C to the base 60.

[0115] The channel 72 and the opening 74 in combination with the attachment mechanism 82 form a lock for coupling each reaming member 25 to the base 10. The lock is latching.

[0116] With reference to Figure 5 The hook 86 is defined at the end of the protrusion forming the attachment mechanism 82. The hook 86 is able to engage the opening 74 to couple the reaming member to the base 10.

[0117] The attachment mechanism 82 is spring biased toward a position in which the hook 86 can engage the opening 74. Engagement of the hook 86 with the opening 74 couples the reaming members 76A, 76B, 76C to the base 60.

[0118] Referring to Figure 6 , the post 69 includes a plurality of channels 72. The plurality of channels 72 extend into the post 69 from the apex 70. The post includes six channels 72, each having an opening 74A, 74B, 74C, 74D, 74E, 74F on the surface forming the apex 70. Each opening 74A, 74B, 74C, 74D, 74E, 74F and corresponding channel 72 is square in shape.

[0119] The openings 74A, 74B, 74C, 74D, 74E, 74F are spaced around the apex 70. The openings 74A, 74B, 74C, 74D, 74E, 74F are equidistant from one another.

[0120] The post 69 has a central axis CA. Each opening 74A, 74B, 74C, 74D, 74E, 74F and corresponding channel 72 is equidistant from one another and from the central axis CA.

[0121] The openings 74A, 74B, 74C, 74D, 74E, 74F and their corresponding channels 72 form pairs. The pairs are formed by openings on opposite sides of the post 69 relative to the central axis CA. A first pair is formed by openings 74A, 74D. A second pair is formed by openings 74B, 74E. A third pair is formed by openings 74C, 74F.

[0122] Each pair is arranged to receive and retain an attachment mechanism 82 of a reaming drill member 75 of the plurality of reaming drill members 76A, 76B, 76C.

[0123] The base 60 includes a plurality of recesses 67. Each recess 67 is arranged to receive a reaming drill member 75 and to minimize deformation of the reaming drill member 75 during a reaming procedure.

[0124] Referring to Figure 7 , the support surface 66 includes a plurality of recesses 67A, 67B, 67C. Each recess 67A, 67B, 67C is circular in shape. Each recess 67A, 67B, 67C is arranged to receive an equator 85A, 85B, 85C of a respective reaming drill member 76A, 76B, 76C. Each recess 67A, 67B, 67C has a width selected to receive its respective equator 85A, 85B, 85C. The width is selected so that the equator fits tightly into the recess.

[0125] Each recess 67A, 67B, 67C has a diameter. Each recess 67A, 67B, 67C has a diameter of the equator 85A, 85B, 85C of its respective reamer member 76A, 76B, 76C selected to be received.

[0126] The first reamer member 76A is a first reamer member of a plurality of reamer members 75 to be connected to the base 10. The first reamer member 76A has the smallest diameter when compared to the second reamer member 76B and the third reamer member 76C. The second reamer member 76B has a diameter that is greater than the first reamer member 76A and less than the third reamer member 76C. The third reamer member 76C has the largest diameter.

[0127] The diameter of the reaming assembly increases with each successive reamer member 76A, 76B, 76C being placed over the underlying reamer member. The final diameter of the largest reamer member corresponds to the total diameter of the cavity to be prepared in the bone, for example. The final diameter can be 36 mm, for example. The diameter of the reamer members can increase in increments of 2 mm until the final diameter is reached. For example, the reamer member 76A can have a diameter of 32 mm, the reamer member 76B can have a diameter of 34 mm, and the reamer member 76C can have a diameter of 36 mm. In another example, the final diameter can be 62 mm. In this example, the reamer member 76A can have a diameter of 58 mm, the reamer member 76B can have a diameter of 60 mm, and the reamer member 76C can have a diameter of 62 mm. As will be appreciated by those skilled in the art, the final reaming diameter and the increments can of course vary. As will be appreciated by those skilled in the art, the diameters of the recesses and equators vary to correspond to the diameters of the reamer members 76A, 76B, 76C.

[0128] While the second embodiment has been described as having three remaining members, those skilled in the art will of course appreciate that any number of reamer members is of course possible within the scope of the present invention.

[0129] With reference to Figure 4 , in the first configuration, the first reamer member 76A is coupled to the base 60 and is used to ream a cavity in the bone of the first dimension. In the second configuration, the second reamer member 76B is coupled to the base 60 and is used to ream a cavity in the bone of the second dimension.

[0130] In the third configuration, with reference to Figure 8 , the third reamer member 76C is coupled to the base 60 to form the reaming assembly 2 having the third diameter. In the third configuration, the reaming assembly 2 is used to ream the cavity having the third dimension using the plurality of cutters 81C.

[0131] The materials for the second embodiment correspond to the materials for the first embodiment.

[0132] Figure 9 A reaming assembly 3 of a third embodiment of the invention is shown. The reaming assembly 3 has a base 110 and a plurality of reaming members 125. The plurality of reaming members 125 are coupleable to the base 110 to form the reaming assembly 3. Similar to the first and second embodiments, the reaming members 125 are stacked on top of each other to form a reamer assembly with increasing diameter sizes.

[0133] The reaming assembly 3 is substantially the same as the reaming assembly of the first embodiment, except for the attachment mechanism.

[0134] In the third embodiment, the reaming assembly 3 has a base 110 to which the attachment mechanism 132 of the reaming members 125 is coupled.

[0135] The base 110 has an edge 117 that is defined at the intersection of its substantially hemispherical support surface 116 and its substantially planar connector surface 112.

[0136] The base 110 has first and second openings 119 located on either side of the support surface 116. The openings 119 are substantially semicircular in shape.

[0137] The reaming members 125 have a pole 134 that extends to an equator 135. The equator 135 defines a peripheral base of the reaming members 125. The attachment mechanism 132 has a first protrusion 132A and a second protrusion 132B that extend from the equator 135. Each protrusion 132A, 132B is resilient. Each protrusion 132A, 132B has a hook 136. The hooks 136 are arranged to engage the edge 117 to couple the reaming members 125 to the base 110.

[0138] The edge 117 in combination with the attachment mechanism 132 forms a lock for coupling the reaming members 125 to the base 110.

[0139] The third embodiment also has features for minimizing rotation of the reaming members 125 relative to the base 110. The channels 119 of the base and the first and second notches 138 arranged on either side of the reaming members 125 provide anti-rotation features.

[0140] With reference to Figure 10A and Figure 10B the reaming assembly 3 is assembled. Figure 10A A first side of the reaming assembly 3 is shown, with the first notch 138A arranged first opening 119A. Figure 10BThe opposite second side of the reaming assembly 3 is shown, with the second recess 138B disposing the second opening 119B. In operation, as the recesses 138A, 138B are positioned through the openings 119A, 119B, rotation of the reamer assembly 3 about the axis C causes the recesses 138A, 138B to abut the sidewalls defining the openings 119A, 119B to minimize rotation of the reaming member or reaming member 125 coupled to the base 110.

[0141] Figure 11 A fourth embodiment of the invention is shown. The fourth embodiment is a reamer assembly 4 for reaming a bone, such as an acetabulum. The reamer assembly 4 has a base 160 and a plurality of reaming members 175. The plurality of reaming members 175 are couplable to the base 160 to form an assembly, which can be referred to herein interchangeably as the reamer 4 or the reaming assembly 4.

[0142] The base 160 has a connector surface 162 in which a connector 164 is located. The connector 164 can be configured to receive a driver coupling. The driver coupling can be a conventional reamer coupling, or it can be Figure 15 the coupling 201 of the driver 200 shown, Figure 16 the coupling 301 of the driver 300 shown in or any other suitable driver coupling. The drivers 200, 300 are for applying rotational motion to the reamer 1 in use.

[0143] The base 160 has a support surface 166. The support surface 166 has an outer shape. The outer shape is selected to provide a seating surface that supports the plurality of reaming members 175 in use.

[0144] The support surface 166 extends from an outer periphery 168 to a pole 170. The pole 170 is located on an axis D about which the reamer assembly 4 is rotated by the reamer driver 200, 300.

[0145] The support surface 166 provides overall support and rigidity to each reaming member 175 disposed on the base. The support surface 166 is a hemispherical dome. Of course, this shape is merely exemplary and other support surface shapes are certainly possible without departing from the scope of the invention.

[0146] With reference to Figure 12 the support surface 166 has a groove 172. The groove 172 extends longitudinally from the pole 170 to the outer periphery 168. In a preferred embodiment, the pole 170 is the midpoint of the groove 172. The groove 172 extends away from the pole 170 towards opposite sides of the outer periphery 168 in two longitudinal directions.

[0147] The recess 172 terminates adjacent the outer perimeter at a step 173. The step 173 has a counterbore member coupling 174. The counterbore member coupling 174 has a slot 174A and a button 174B. The slot 174A is arranged to receive a portion of a counterbore member 175 to couple the counterbore member 175 to the body 160. First and second teeth 174C and 174D are arranged on laterally opposite sides of the slot 174A.

[0148] The button 174B can be depressed to release the counterbore member 175 from the slot 174A.

[0149] The recess 172 is sized to receive the counterbore member 175 with a close fit. The close fit minimizes rotation of the remaining member 175 relative to the base 160.

[0150] The recess 172 has a width of approximately 20% of the diameter of the selected counterbore member 175. For example, where the counterbore assembly 4 has a diameter of 36 mm, the recess has a width of 7.2 mm. For example, where the counterbore assembly 4 has a diameter of 63 mm, the recess has a width of 12.3 mm.

[0151] The recess has a depth of 1.2 mm. These dimensions are selected to provide a close fit with the counterbore member 175.

[0152] The base 160 has a set of alignment rollers 186.

[0153] Referring to Figure 11 The set of alignment rollers 186 includes a first alignment roller 186A and a second alignment roller 186B. The alignment rollers are located on opposite sides of the base 160. In use, the set of alignment rollers 186 acts to align the counterbore head assembly 4 with a cavity being counterbored.

[0154] Referring to Figure 11 The counterbore member 175 is engageable with the base 160 to form the counterbore assembly 4.

[0155] Figure 13 The counterbore member 175 is shown. The counterbore member 175 is similar to a curved band. The counterbore member 175 is shaped to match the shape of the recess 172. The width of the counterbore member 175 corresponds to the width of the recess 172 as described above. The shape and width are selected to enable a close fit to be formed between the counterbore member 175 and the recess 172.

[0156] The counterbore member 175 has a seating surface 178, a counterboring surface 180 and an attachment mechanism 182.

[0157] The seating surface 178 is configured to be disposed above the underlying support surface 166. The reaming surface 180 is part of the reaming member 175 that engages the acetabulum for preparing the bone to receive the implant. The reaming surface 180 has cutters 181 disposed to remove bone and other tissue in the process of preparing the bone to receive the implant.

[0158] The seating surface 178, the reaming surface 180, and the attachment mechanism 182 of the reaming member 175 form a body of the reaming member in which the cutters 181 are disposed.

[0159] The reaming drill member coupling 174 and the attachment mechanism 182 form a lock for attaching the reaming member 175 to the base 160.

[0160] The attachment mechanism 182 has a first protrusion 182A and a second protrusion 182B. The first and second protrusions extend from opposite ends of the reaming member 175.

[0161] Each protrusion 182A, 182B has a first hook 184A and a second hook 184B.

[0162] Figure 14 A plurality of reaming assemblies 4 is shown. The plurality of reaming assemblies 4 has a common base 160 on which reaming members 175 of a plurality of reaming members 176A, 176B, 176C, 176D are disposed.

[0163] The plurality of reaming members 176A, 176B, 176C, 176D have different heights H1, H2, H3, H4.

[0164] The first reaming member 176A has a height H1.

[0165] The second reaming member 176B has a height H2.

[0166] The third reaming member 176C has a height H3.

[0167] The fourth reaming member 176D has a height H4.

[0168] The heights H1, H2, H3, H4 increase consecutively. For example, the height H1 is less than the height H2, the height H2 is less than the height H3, and the height H3 is less than the height H4.

[0169] The height can be increased in increments of 0.5mm. In one example, the reaming assembly 4 can be used to ream a cavity having a final diameter of 32mm. The reaming members can start at 30mm and increase in increments of 0.5mm. In another example, the final diameter can be 62mm. In this example, the reaming members can start at a reaming diameter of 60mm. As will be appreciated by those skilled in the art, the final reaming diameter and increments can of course vary.

[0170] The variability of the heights H1, H2, H3, H4 enables the operator to successively increase the radius of the reaming assembly 4. The successive increase in the radius enables the operator to prepare the cavity in the bone in stages. For example, in a first stage, a first reaming drill assembly 4A having a first reaming member 176A disposed on the common base 160 defines a reaming assembly 4 having a first radius R1. The operator can use this first reaming drill assembly 4A to ream a cavity having a first diameter D1. In a second stage, a second reaming drill assembly 4B having a second reaming member 176B disposed on the common base 160 defines a reaming drill assembly 4 having a second radius R2. The operator can use this second reaming drill assembly 4B to ream a cavity having a second diameter greater than the first diameter. This process of successively increasing the radius of the reaming drill assembly 4 in stages is repeated using a third reaming drill assembly 4C, a fourth reaming drill assembly 4D, and other reaming drill assemblies that increase the radius until the operator has prepared the cavity in the bone at the desired diameter.

[0171] For ease of reference, the radii R1, R2, R3, R4 have been depicted by imaginary dashed lines shown by Figure 14

[0172] To form the assemblies 4A, 4B, 4C, 4D, the respective reaming members 176A, 176B, 176C, 176D are coupled to the base 160 by engaging the respective attachment mechanisms 182 with the reaming drill member coupling 174.

[0173] Referring to Figure 15 , the reaming drill 4 is configured to be used by being connected to a reaming drill driver. The reaming drill 4 is coupled to the driver for use in a reaming process. During the reaming process, the reaming drill 4 is engaged with a portion of the bone to be reamed. The reaming drill driver to which the reaming drill 4 is coupled is activated to cause the reaming drill 4 to rotate. The rotating reaming drill 4 is pressed against the bone to form the cavity.

[0174] In a first stage, the base 160 of the reaming drill 4 is coupled to the coupler 201 of the example reaming drill 200.

[0175] The operator, knowing the final radius of the cavity to be formed in the bone, selects a reaming member 175 having a radius that is less than the final radius. For example, the operator can select the reaming member 176A.​

[0176] The operator then attaches the reaming member 175 to the base 160 to form the first starter reaming drill 4.

[0177] A reamer 4, with a radius smaller than the final radius, engages with a portion of the hole to be reamed in the bone. A reamer actuator 200 is activated to rotate the reamer 4. The rotating reamer 4 is pressed against the bone to form an initiator cavity. The radius of the initiator cavity is smaller than the final radius.

[0178] After the starter cavity is formed, the operator removes the in-situ reaming member 175. The operator then selects a reaming member with an increased radius and attaches it to the base 160.

[0179] The operator repeats this process until a cavity of the desired depth and radius is formed in the bone.

[0180] The reaming members 176A, 176B, 176C, and 176D are connected to the base 160 using a first protrusion 182A and a second protrusion 182B. The protrusions 182A and 182B are pushed into a slot 174A located on either side of the base 160. The reaming members 176A, 176B, 176C, and 176D are pushed or pressed until their hooks 184A and 184B are engaged by the teeth 174C and 174D. With the teeth 174C and 174D engaged with the hooks 184A and 184B, one of the combinations 4A, 4B, 4C, and 4D is formed, and this combination can be used by the operator for the aforementioned reaming purpose.

[0181] After reaming has been performed, and the operator intends to ream a cavity with a larger diameter, the button 174B on either side of the base 160 can be pressed to remove the reaming members 176A, 176B, 176C, and 176D currently attached to the base 160. Pressing button 174B releases hooks 184A and 184B from the corresponding teeth 174C and 174D, allowing the reaming members 176A, 176B, 176C, and 176D to be removed from the base by the operator.

[0182] exist Figures 11 to 14 In the exemplary embodiment shown, the base 160 is made of a plastic material. Suitable plastic materials include polyacrylamide. For example, the base 160 may be made of polyacrylamide sold under the trade name IXEF. Of course, the base 160 may be made of other suitable materials.

[0183] The bodies 178, 180, 182 of the reaming member 175 are made of a plastic material. Suitable plastic materials include polyacrylamide. For example, the reaming member 175 can be made in the form of polyacrylamide sold under the trade name IXEF. Of course, the reaming member 175 can be made of other suitable materials.

[0184] The cutters 181 are made of a metallic material. Suitable metals include stainless steel. For example, each reaming member 26A, 26B, 26C, 26D can be made of 17-4 PH type stainless steel. Of course, the cutters 181 can be made of other suitable materials.

[0185] The bases 160 and the bodies 178, 180, 182 of the reaming member 175 are manufactured using plastic injection molding. The cutters 181 are manufactured by stamping the cutters out of a sheet of metal, thereby sharpening the edges to form blades. The cutters 181 are then arranged and secured to desired locations in the bodies 178, 180, 182 of the reaming member 175.

[0186] Note that all papers and documents submitted with this application, including any provisional application(s) from which this application claims priority, as well as any papers and documents submitted prior to or with this specification, are hereby incorporated by reference in their entirety as if fully set forth herein.

[0187] All features disclosed in this specification, including any accompanying claims, abstract, and drawings, and any method or process disclosed herein can be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive.

[0188] Unless otherwise defined, all features disclosed in this specification (including any accompanying claims, abstract, and drawings) can be replaced by alternative features serving the same, equivalent or similar purpose, so that each disclosed feature is only an example of a generic series of equivalent or similar features.

[0189] The application is not restricted to the details of the foregoing embodiments. The application extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract, and drawings), or to the steps of any method or process so disclosed.

[0190] While the preferred embodiments of the application have been illustrated and described, it will be understood by those skilled in the art that changes can be made without departing from the scope of the application as defined by the claims.

[0191] In this specification, the term "comprise", "comprises", "comprising" or similar terms, where used in this specification, are intended to mean that the system, method, or apparatus includes the stated element but not other elements not specifically stated. Thus, for example, the term "comprising" is used in this specification to mean that the system, method, or apparatus includes the stated element but not other elements not specifically stated.

[0192] The reference in this specification to any prior publication is not, and should not be taken to be, an acknowledgment or admission that the prior publication forms part of the common general knowledge in the field of endeavour in any country in the world.

[0193] It will of course be understood that this description has been given by way of example only and that modifications and variations can be made by those skilled in the art without departing from the scope of the application defined in the claims.

Claims

1. An assembly for reaming a bone, comprising: a base including a connector adapted to couple the base to a driver and a first support surface; a first reaming member including: a first seating surface shaped to seat the first reaming member over the first support surface; a first reaming surface adapted to ream a bone to a first diameter; and a first attachment mechanism attaching the first reaming member to the base; wherein the first reaming surface provides a second support surface; a second reaming member including: a second seating surface shaped to seat the second reaming member over the second support surface; a second reaming surface adapted to ream a bone to a second diameter; and a second attachment mechanism attaching the second reaming member to the base; wherein the second diameter is greater than the first diameter.

2. The assembly of claim 1, wherein the first reaming member and the second reaming member are releasably attachable to the base.

3. The assembly of claim 1 or claim 2, wherein the second reaming surface is separated from the first reaming surface by a predetermined thickness, thereby increasing the second diameter relative to the first diameter.

4. The assembly of claim 1 or claim 2, wherein the first support surface has an outer shape and the first seating surface has an inner shape that matches the outer shape.

5. The assembly of claim 4, wherein the outer shape is hemispherical and the first seating surface has a curvature that conforms to the outer shape.

6. The assembly of claim 1 or claim 2, wherein the base includes a first recess extending into the first support surface, the first reaming member includes a first prong and a second recess, and the second reaming member includes a second prong; wherein the first recess is configured to receive the first prong to attach the first reaming member to the base; and wherein the second recess is configured to receive the second prong to attach the second reaming member to the base.

7. The assembly of claim 1 or claim 2, wherein the second reaming member positioned over the first reaming member is attached to the first reaming member by the second attachment mechanism to attach the second reaming member to the base.

8. A kit, comprising: a base including a connector adapted to couple the base to a driver and a support surface; a first reaming member including: a first seating surface shaped to seat the first reaming member over the support surface; a first reaming surface adapted to ream a bone to a first diameter; and a first attachment mechanism configurable to attach the first reaming member to the base; and a second reaming member including: a second seating surface shaped to seat the second reaming member over the support surface; a second reaming surface adapted to ream a bone to a second diameter; and a second attachment mechanism configurable to attach the second reaming member to the base. a second reaming member comprising: a second seating surface shaped to seat the second reaming member over the first reaming surface; a second reaming surface adapted to ream bone to a second diameter; and a second attachment mechanism configurable to attach the second reaming member to the base; wherein the second diameter is greater than the first diameter.

9. A method of assembling a reamer, comprising: providing a base comprising a connector adapted to couple the base to a driver and an outer surface defining a support surface; providing a first reaming member comprising: a first inner surface shaped to seat the first reaming member on the support surface; a first outer surface adapted to ream bone; and a first attachment mechanism attaching the first reaming member to the base; engaging the first inner surface with the support surface; attaching the first reaming member to the base with the attachment mechanism; providing a second reaming member comprising: a second inner surface shaped to seat the second reaming member on the first outer surface; a second outer surface adapted to ream bone; and a second attachment mechanism attaching the second reaming member to the base; engaging the second inner surface with the first outer surface; and attaching the second reaming member to the base with the second attachment mechanism.

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