Abstract:
A kit for use in orthopaedic surgery. The kit includes a plurality of heads, at least two of the plurality of heads having a different diameter. Each of the plurality of heads includes a female taper. The kit further includes a plurality of sleeves, at least two of the plurality of sleeves having a different size. Each of the plurality of sleeves has a male taper. An extractor tool is also included and has a handle and a plurality of tips, each of the plurality of tips including a flexible portion.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    Priority is claimed to the following application: U.S. patent application Ser. No. 11/931,495 entitled, “TAPER SLEEVE EXTRACTOR” filed on Oct. 31, 2007, by David W. Daniels, et al (Docket No. DEP5978USNP), which is herein incorporated by reference in its entirety. 
     
    
     TECHNICAL FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to the field of orthopaedics, and more particularly, to an implant for use in arthroplasty. 
       BACKGROUND OF THE INVENTION 
       [0003]    Patients who suffer from the pain and immobility caused by osteoarthritis and rheumatoid arthritis have an option of joint replacement surgery. Joint replacement surgery is quite common and enables many individuals to function properly when it would not be otherwise possible to do so. Artificial joints are usually comprised of metal, ceramic and/or plastic components that are fixed to existing bone. 
         [0004]    Such joint replacement surgery is otherwise known as joint arthroplasty. Joint arthroplasty is a well-known surgical procedure by which a diseased and/or damaged joint is replaced with a prosthetic joint. In a typical total joint arthroplasty, the ends or distal portions of the bones adjacent to the joint are resected or a portion of the distal part of the bone is removed and the artificial joint is secured thereto. 
         [0005]    There are known to exist many designs and methods for manufacturing implantable articles, such as bone prostheses. Such bone prostheses include components of artificial joints such as elbows, hips, knees and shoulders. 
         [0006]    Currently in total hip arthroplasty, a major critical concern is the instability of the joint. Instability is associated with dislocation. Dislocation is particularly a problem in total hip arthroplasty. 
         [0007]    Factors related to dislocation include surgical technique, implant design, implant positioning and patient related factors. In total hip arthroplasty, implant systems address this concern by offering a series of products with a range of lateral offsets, neck offsets, head offsets and leg lengths. The combination of these four factors affects the laxity of the soft tissue. By optimizing the biomechanics, the surgeon can provide a patient a stable hip that is more resistant to dislocation. 
         [0008]    In the case of a damaged hip joint, replacement involves resection of the proximal femur and implantation of the femoral component of an orthopaedic joint, which includes a stem part that can be received in the intramedullary canal, and a head part with a convex bearing surface. The patient&#39;s acetabulum is prepared to receive the acetabular component of the joint prosthesis, which provides a concave bearing surface to articulate with the bearing surface on the femoral component. Frequently, bone cement is used to affix the components of the prosthesis within their respective prepared bone cavities. 
         [0009]    When the condition of the femoral bone tissue is generally good, it can be desirable to retain much of the proximal femur. Techniques have been developed in which the femoral head is fitted within a hollow resurfacing shell. The resurfacing shell has a convex outer surface that is highly polished which enables it to act against the hollow bearing surface of an acetabular component. Such techniques are referred to as Articular Surface Replacement (ASR) techniques. They have the advantage that the quantity of bone that has to be removed from the head of the bone is only small. A tool which can be used to prepare the head in this way is disclosed in International patent application no. GB03/04303. 
         [0010]    In some ASR kits, there are a large number of femoral heads that can fit on various stem tapers with the use of sleeves. The sleeves have an inner and an outer taper. The inner taper engages with the stem and the outer taper engages with the head. The sleeves also provide various neck offsets to allow for neck length adjustments. Once the surgeon assembles the head and sleeve, it is difficult to disassemble them because of the taper. However, surgeons may sometimes need to do so to achieve better range of motion or a different neck offset. If the surgeon cannot easily remove the sleeve from the head, the surgeon must open another head and sleeve, which leads to waste. 
         [0011]    Therefore, there is a need for an instrument that allows the surgeon to remove the sleeve from the head without ruining either the head or the sleeve. 
         [0012]    The present invention is directed to alleviate at least some of the problems with the prior art. 
       SUMMARY OF THE INVENTION 
       [0013]    According to one embodiment of the present invention, an extractor for extracting a first component used in an orthopaedic implant from a second component used in an orthopaedic implant is provided. The extractor includes a handle and an extractor tip. The extractor tip has a proximal end and a distal end. The proximal end connects to the handle and the distal end includes a flexible portion adapted to engage the first component. 
         [0014]    According to another embodiment of the present invention, a kit for use in orthopaedic surgery is provided. The kit includes a plurality of heads. At least two of the plurality of heads have a different diameter. Each of the plurality of heads include a female taper. The kit also includes a plurality of sleeves, at least two of the plurality of sleeves having a different size. Each of the plurality of sleeves having a male taper. The kit also includes an extractor tool. The extractor tool includes a handle and a plurality of tips. Each of the plurality of tips includes a flexible portion. 
         [0015]    According to yet another embodiment of the present invention, a method for removing a first orthopaedic component from a second orthopaedic component is provided. The first and second orthopaedic components are joined via a taper lock. The method includes providing an extractor tool having a handle and an extractor tip that has a flexible portion. The flexible portion is inserted through a bore in the first component. The flexible portion snaps open, and a force is exerted against the handle of the extractor tool, thereby loosening the taper between the first and second components. The first component is held in place while the second component falls away, thereby removing the first component from the second component. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]    For a more complete understanding of the present invention and the advantages thereof, reference is now made to the following description taken in connection with the accompanying drawings, in which: 
           [0017]      FIG. 1  is a perspective view of a orthopaedic implant including a head, a sleeve, and a stem according to one embodiment of the present invention; 
           [0018]      FIG. 2  is a cross-sectional view of a head and sleeve engaged in the head according to one embodiment of the present invention; 
           [0019]      FIG. 3  is a plan view of an extractor tool according to one embodiment of the present invention; 
           [0020]      FIG. 4   a  is a cross-sectional view of the handle; 
           [0021]      FIG. 4   b  is a cross-sectional view of the extractor tip of  FIG. 3 ; 
           [0022]      FIG. 5  is a perspective view of the handle of  FIG. 3 ; 
           [0023]      FIG. 6  is an exploded view of the handle of  FIG. 3 ; 
           [0024]      FIG. 7  is a perspective view of the extractor tip of  FIG. 3 ; 
           [0025]      FIG. 8  is a cross-sectional view of an extractor tip according to one embodiment of the present invention inserted into an orthopaedic implant; 
           [0026]      FIG. 9  is a flow chart illustrating the use of the extractor tool according to one embodiment of the present invention; and 
           [0027]      FIG. 10  is a plan view of a kit according to one embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0028]    Embodiments of the present invention and the advantages thereof are best understood by referring to the following descriptions and drawings, wherein like numerals are used for like and corresponding parts of the drawings. 
         [0029]    Referring now to  FIG. 1 , an implant  10  is illustrated. The implant  10  includes a head  12 , a sleeve  14 , and a stem  16 . The stem  16  includes a tapered portion  18 . The tapered portion  18  includes a male taper  20  that matches an internal female taper  22  on the sleeve  14  ( FIG. 2 ). In other words, the taper angle of the internal female taper  22  of the sleeve  14  matches the taper angle of the male taper  20  of the stem  16 . The sleeve  14  also includes an external male taper  24  that matches a female taper  26  of the head  12  ( FIG. 2 ). In other words, the taper angle of the external male taper  24  of the sleeve  14  matches the taper angle of the female taper  26  of the head  12 . 
         [0030]    In assembling the head  12 , sleeve  14 , and stem  16 , the surgeon would insert the sleeve  14  into the head  12  and lock the sleeve  14  and the head  12  via the tapers  24 ,  26 . However, if the surgeon would need to remove the sleeve  14  from the head  12 , the tapers  24 ,  26  are difficult, if not impossible, to disengage without the use of a tool. 
         [0031]    Turning now to  FIG. 3 , an extractor tool  30  is shown. The extractor tool  30  includes a handle  32  and an extractor tip  34 . The handle  32  includes a proximal end  36  and a distal end  38 . The handle  32  includes a gripping portion  39 . The proximal end  36  includes an impaction mechanism  40 . As shown in  FIG. 6 , the impaction mechanism  40  includes a plate  41   a  and a shaft  41   b . During use of the tool, the plate  41   a  would be struck by the surgeon using a tool. As shown in  FIGS. 4 and 5 , the shaft  41   b  extends through the length of the handle  32 . When the handle  32  is connected to the extractor tip  34 , the shaft  41   b  will extend into the extractor tip  34 , as shown in  FIG. 3 . 
         [0032]    The distal end  38  is connected to the extractor tip  34 . A locking mechanism  42  on the handle  32  is used to connect the extractor tip  34  to the handle  32 . As shown in the cross-section view of the tool  30  in  FIG. 4   a  the locking mechanism  42  is a spring-loaded button including a button  44 , an opening  46 , a button housing  47 , and a spring  48 . As shown in  FIG. 4   a , the locking mechanism  42  engages a recess  50  in the extractor tip  34 . The locking mechanism  42  thus holds the extractor tip  34  in a predetermined location. If the user should wish to remove the extractor tip  34 , the user presses on the button  44  and releases the extractor tip. When the button  44  is not being activated, the spring  48  exerts a force upward, locking the extractor tip  34  in place. The individual pieces of the locking mechanism  42  are shown in greater detail in the exploded view of the handle  32  in  FIG. 6 . Although the illustrated locking mechanism is a button utilizing a spring, other known locking mechanisms may be used. For example, the extractor tip  34  could be threaded on or could have a post/slot locking mechanism. 
         [0033]    As shown in  FIGS. 3 ,  4   a  and  4   b , the extractor tip  34  includes a proximal end  51   a  and a distal end  51   b . At the distal end  51   b , the extractor tip  34  includes a flexible portion, which in this embodiment includes a plurality of spaced apart legs  52 . Each leg  52  extends generally parallel to a longitudinal axis of the extractor tip  34 . Distal to the legs  52 , each leg  52  includes a foot  54  that extends generally tranverse to the longitudinal axis  55 . 
         [0034]    Turning now to  FIG. 7 , the extractor tip  34 , and specifically, the legs  52  and feet  54 , will be shown in greater detail. As shown in this embodiment, there are four legs  52  and four feet  54 . Because of the space between each of the legs  52 , the legs are somewhat flexible and can move when a force is applied against them. Although the illustrated embodiment shows four legs and four feet, it should be understood that the number of legs and feet could be varied. 
         [0035]    Turning now to  FIG. 8 , the extractor tool  30  is shown inserted into a head  12  and sleeve  14  that have been locked together. As shown, there is a small gap  56  between the top of the sleeve  14  and the inner portion of the head  12 . When the extractor tip  34  is inserted into the sleeve  14 , the feet  54  push into the gap  56  and then expand to grasp a top end of the sleeve  14 . The impaction mechanism  40  can then be struck by a hammer or other tool, creating a vibration that travels the length of the tool  30  to the feet  54 . The vibration at the feet  54  causes the tapers  24 ,  26  of the head  12  and sleeve  14  to be disengaged, allowing the surgeon to remove the sleeve  14  from the head  12 . 
         [0036]    The extractor tip  34  may be made of a sterilizable metal such as stainless steel. Other metals such as aluminums or radels may also be used. The gripping portion  39  of the handle  32  may be made of radel, aluminums, rubber, while the locking mechanism  42 , impaction mechanism  40  and strike plate are all made of a sterilizable metal such as stainless steel. In some embodiments the extractor tool  30  may be disposable and all of the parts, except for the shaft  41   b  may be made of a disposable plastic such as polyethylene or radel. 
         [0037]    Turning now to  FIG. 9 , a flow chart is illustrated that describes the use of the extractor tool  30  according to one embodiment of the invention. The surgeon assembles the extractor tool  30  by pushing down the button  44  (s 100 ) while inserting the extractor tip  34  into the opening  46  at step s 102 . Once the extractor tip  34  is in place, the surgeon releases the button  44 , locking the extractor tip  34  to the handle  32  at step s 104 . The surgeon then pushes the extractor tool  30  against the head  12 , thereby inserting the feet  54  of the extractor tip  34  through the internal female taper  22  of the sleeve  14  and into the gap  56  (s 106 ). Once the feet  54  reach the gap  56  they are no longer under compression, so the feet  54  snap open into the gap  56 . Once the impact force is applied, the feet  54  serve as a holding device to keep the sleeve  14  attached to the extractor tip  34  when the head falls away (step s 108 ). Next, at step s 110 , the surgeon taps the impaction plate  41   a  with a hammer or other tool (or by hand), creating a force that travels through the handle  32  and into the extractor tool  34 . The force sends a vibration through the tapers, thereby disengaging the taper between the external male taper  24  of the sleeve  14  from the female taper  26  of the head  12 . The head will fall off the extractor tip, leaving the sleeve still attached at step s 112 . 
         [0038]    Turning now to  FIG. 10 , a kit  200  according to one embodiment of the present invention is shown. The kit includes a plurality of heads  212 , a plurality of sleeves  214 , a plurality of stems  216 , and an extractor tool  230 . The extractor tool  230  includes a handle  232  and a plurality of extractor tips  234 . The diameters of the plurality of heads  212  are different. The heads  212  also include a female taper  226  and the taper angle of these female tapers  226  may also vary. The plurality of sleeves  214  each include an internal female taper  222  and an external male taper  224 . The sleeves  214  may vary in size (e.g., length, width, etc. . . . ) as well as in taper angle. The tapers of the stems  216  may also vary. 
         [0039]    The extractor tips  234  each include a flexible end having a plurality of legs  252 , each of the legs  252  having a foot  254 . The extractor tips  234  may also vary in length and in width. Because the length of the sleeves  214  may vary, the length of the legs  254  on the various extractor tips  234  may vary to fit in the selected sleeve. Also, because the taper angles of the female taper  226  of the head  212  may vary, the size of the feet  254  and/or the diameter of the extractor tip  234  may also vary. The extractor tips  234  may also vary the number of both the legs  252  and the feet  254 . 
         [0040]    In use, the surgeon would select one of the plurality of heads  212  and one of the plurality of sleeves  214  and assemble them for use. Should the surgeon need to disassemble the sleeve  214  and the head  212 , the surgeon would then select an extractor tip  234  from the plurality of tips  234 . The selected extractor tip would have the appropriate length and width to fit into the sleeve  214 . The surgeon would then lock the selected extractor tip  234  into the handle and proceed as described in reference to  FIG. 9 . 
         [0041]    Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions, and alterations can be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.