Abstract:
A suture anchor for securing a suture to a bone, comprising a tubular housing for disposition in a hole in a bone, the tubular housing being configured for selective expansion; and an expander for expanding the tubular housing; whereby when a suture is disposed between the tubular housing and a wall of the hole, and the tubular housing is expanded, the tubular housing will bind the suture to the bone.

Description:
REFERENCE TO PRIOR PATENT APPLICATION  
       [0001]     This patent application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/650,759, filed Feb. 7, 2005 by Joseph H. Sklar for KNOTLESS SUTURE ANCHOR (Attorney&#39;s Docket No. SKLAR-32A PROV), which patent application is hereby incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION  
       [0002]     This invention relates to surgical devices in general, and more particularly to suture anchors of the sort adapted to anchor a piece of conventional suture in bone.  
       BACKGROUND OF THE INVENTION  
       [0003]     Numerous devices are currently available to attach objects to bone. More particularly, screws, staples, cement and sutures have all been used to attach soft tissue (e.g., ligaments, tendons, muscles, etc.), bone and inanimate objects (e.g., prostheses) to bone.  
         [0004]     In certain situations it is desirable to anchor a piece of conventional suture in the bone, so that the suture can be used to attach the desired object (e.g., a ligament or prosthesis) to the bone. This is traditionally accomplished by forming a hole in the host bone and then positioning a suture anchor in the hole, with the suture anchor securing the suture to the host bone.  
         [0005]     Traditionally, suture anchors have anchored one end of the suture in bone, with the free end of the suture engaging the tissue, and then the suture is knotted so as to hold the tissue in place. Unfortunately, however, it can be difficult and/or inconvenient to knot the suture when access to the surgical site is limited, e.g., as in the case of an arthroscopic procedure.  
         [0006]     As a result, one object of the present invention is to provide a new and improved suture anchor which can be used to attach an object to bone without requiring that a knot be tied.  
         [0007]     And another object of the present invention is to provide a new and improved suture anchor which is easy and convenient to use and which provides significant holding strength.  
       SUMMARY OF THE INVENTION  
       [0008]     These and other objects of the present invention are achieved through the provision and use of a novel suture anchor which preferably comprises a sheath or outer expandable member (hereinafter sometimes referred to collectively as a “sheath”) capable of assuming two different configurations, (i) a first configuration having a reduced cross-sectional diameter, and (ii) a second configuration having an enlarged cross-sectional diameter. The sheath or member is positioned in the bone tunnel while in its first, reduced configuration, with the suture positioned between the sheath and the wall of the bone tunnel, and then the sheath is transitioned into its second, expanded configuration, so that the suture is captured between the wall of the bone tunnel and the wall of the expanded sheath. By properly attaching the suture to the object which is to be captured to the bone, and by properly positioning the suture vis-à-vis the sheath before the sheath is secured in the bone tunnel, an object can be secured to the bone without tying any knots. An expansion screw or mandrel or pin or other element may be used to expand the sheath or member when it is in the bone tunnel.  
         [0009]     Still other objects and features of the present invention will be disclosed or rendered obvious by the following description of the preferred embodiments of the invention. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     These and other objects and features of the present invention will be more fully disclosed or rendered obvious by the following detailed description of the preferred embodiments of the invention, which should be read in conjunction with the accompanying drawings wherein:  
         [0011]      FIGS. 1-6  show a preferred embodiment of the present invention;  
         [0012]      FIG. 7  illustrates one way of securing an object to a bone;  
         [0013]      FIGS. 8 and 9  show additional aspects of the present invention;  
         [0014]      FIGS. 10-13  show another preferred embodiment of the present invention;  
         [0015]      FIGS. 14-18  show another preferred embodiment of the present invention;  
         [0016]      FIGS. 19-23  show another preferred embodiment of the present invention; and  
         [0017]      FIGS. 24-26  show another preferred embodiment of the present invention. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0018]     Looking first at  FIGS. 1 and 2 , there is shown an object  5  (e.g., a rotator cuff) which is to be secured to a bone  10 . In accordance with the present invention, this is accomplished through the use of a suture  15  and a novel suture anchor assembly  20 . Suture anchor assembly  20  in turn comprises a sheath  25  and an expansion screw  30 .  
         [0019]     Sheath  25  is formed out of a flexible or expandable material and is capable of assuming two different configurations, (i) a first configuration ( FIGS. 1 and 2 ) having a reduced cross-sectional diameter, and (ii) a second configuration ( FIGS. 3 and 4 ) having an enlarged cross-sectional diameter. Preferably sheath  25  has a pair of diametrically-opposing side grooves  35  ( FIG. 2 ) running the length of sheath  25 , and a bottom groove  40  spanning the diameter of sheath  25  at the bottom end of the sheath. Side grooves  35  and bottom groove  40  together form a seat for suture  15  so that the suture can be controlled during insertion into the bone tunnel. As shown in  FIG. 3 , bottom groove  40  may be u-shaped to capture sutures.  
         [0020]     Sheath  25  may be formed out of plastic or absorbable material.  
         [0021]     In use, a bone tunnel  45  ( FIG. 1 ) is formed in the host bone, suture anchor assembly  20  is positioned in the state shown in  FIGS. 1, 2  and  5 , suture  15  is passed through the object  5  (e.g., a rotator cuff) which is to be attached to the bone  10 , the two free ends of the suture are placed parallel to one another and tensioned so as to pull object  5  into position relative to bone  10  and then, while tension is maintained on the suture, driver  50  is used to maneuver suture anchor assembly  20  so that sheath  25  is inserted into bone tunnel  45 , with suture  15  seated in side grooves  35  and bottom groove  40  ( FIGS. 1, 2  and  6 ). As shown in  FIG. 6 , suture  15  may be tensioned at point  52 . Driver  50  is used to advance expansion screw  30  into sheath  25 , whereby to expand sheath  25  into its second, expanded state ( FIGS. 3 and 4 ) and thereby secure suture  15  to the wall of bone tunnel  45 . In this way object  5  may be secured to bone  10  without the necessity of tying knots in suture  15 . If desired, several such arrangements ( FIG. 7 ) may be used to secure object  5  to bone  10 . Also, sheath  25  prevents screw  30  from damaging or twisting suture  15  during insertion.  
         [0022]      FIGS. 8 and 9  show additional aspects of the present invention.  
         [0023]     These may include:  
         [0024]     (1) Anti-rotation of sheath: vertically ribbed;  
         [0025]     (2) Quicker screw insertion: high pitch of screw threads;  
         [0026]     (3) Tunnel dilation for soft bone: decreased slippage;  
         [0027]     (4) Slot in sheath: edge of tunnel abrasion reduction; and  
         [0028]     (5) Sheath thicker at tip: increased diameter at bottom of tunnel.  
         [0029]     If desired, fins or tabs or other elements (not shown) may be added to the body of sheath  25  so as to help hold sheath  25  against rotation in bone tunnel  45  while expansion screw  30  is deployed. In the case of a pin or mandrel, the desirability for anti-rotation tabs may be obviated or reduced.  
         [0030]     And expansion screw  30  can have a high pitch rate so as to facilitate quick insertion of the screw into sheath  25 .  
         [0031]     Furthermore, if desired, bone tunnel  45  can be formed using a bone tunnel dilator (not shown) so as to compact the host bone and thereby form a more stable wall for the bone tunnel, whereby to enhance fixation.  
         [0032]     Also, a slot (not shown) can be formed in the outer wall of sheath  25 , so as to provide a space to accommodate the suture: this can help reduce suture abrasion, particularly at the top end of the bone tunnel.  
         [0033]     And sheath  25  can be formed with a thicker wall at the top end of the device, so as to assist fixation.  
         [0034]     Also, suture  15  can have an repeating pattern of expansions, can be made especially coarse or can carry a sleeve, etc. about a portion of its length so as to increase its effective diameter and thereby facilitate gripping by sheath  25 .  
         [0035]     And sheath  25  can include ribbing or roughening along a portion of its exterior so as to facilitate gripping of suture  15 .  
         [0036]     Looking next at  FIGS. 10-13 , in another preferred form of the invention, the bottom end of sheath  25  is formed with a pair of projections or posts  60 . In this arrangement, suture  15  may be placed between posts  60  and then the sheath rotated so as to help wrap suture  15  about the sheath, whereby to help hold suture  15  more stable relative to sheath  25  during insertion into bone tunnel  45 .  
         [0037]     As shown in  FIGS. 14-18 , it is also possible to form sheath  25  with one or more fracture lines (or break points)  65  along its length, so that the bottom end of the sheath may expand outwardly when expansion screw  30  is advanced into sheath  25 . Furthermore, the side walls of sheath  25  may include longitudinal channels  70  for receiving suture  15 ; channels  70  help seat suture  15  to the sheath during insertion of the sheath into the bone tunnel and then, when expansion screw  30  is advanced into the interior of sheath  25 , channels  70  collapse so as to help secure suture  15  to sheath  25  and reduce the dependence by the device upon the interference fit between the expanded sheath and the bone tunnel wall for securing the suture against slippage. Channels  70  are thinner walled to allow crimping when screw is inserted.  
         [0038]     Looking next at  FIGS. 19-22 , it is also possible to form sheath  25  so that its channels  70  include a living hinge  75 ; as a result, when expansion screw  30  expands sheath  25 , suture  15  is captured between the closing elements located on either side of living hinge  75 , achieving the same end result as mentioned in the paragraph immediately above, i.e., capturing the sutures within the sheath itself.  
         [0039]     And looking next at  FIGS. 24-26 , it will be seen that it is also possible to form sheath  25  with a relatively rigid body and helical threads  80 , so that it effectively forms a hollow screw, and to form screw  30  with a diametrical hole  85 . With this construction, sheath (or hollow screw)  25  is set in the bone tunnel, the suture  15  is passed through screw hole  85  and tensioned, and then screw  30  is advanced into sheath (or hollow screw)  25  so as to capture suture  15  to sheath (or hollow screw)  25 . Thus sheath (or hollow screw)  25  is first placed in the bone and then effectively serves as a seat for receiving screw  30 , with the screw  30  capturing the suture to the sheath (or hollow screw)  25 . Alternatively, the suture may be wrapped around a smooth bore portion of the screw  30 , whose threads would be distal, and may be tightened onto sheath (or hollow screw)  25 , thus securing the suture against slippage.