Abstract:
A surgical fastener system for acromioclavicular (AC) joint dislocations, includes a first fastener having an elongate body, and an inner pair of openings centered on the long axis of the body. A closed loop stitch passes through the openings, and the length of the stitch corresponds to the depth of a passage defined between the top of a first hole bored through a patient&#39;s clavicle, and the bottom of a second hole bored through the coracoid in axial alignment with the first hole. A second fastener has an elongate body arranged to slide under a portion of the loop stitch that protrudes from the top of the hole in the clavicle, after the first fastener is set beneath the coracoid and the stitch is pulled upward through the passage. In an alternate embodiment, the second fastener also has an inner pair of openings for passing and engaging the loop stitch.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority under 35 U.S.C. § 119(e) of U.S. Provisional Patent Application No. 61/001,818 filed Nov. 5, 2007, entitled “Double Endobutton Technique for Repair of Complete Acromioclavicular Joint Dislocations”, which is incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention concerns surgical devices for repairing bone fractures or dislocations. 
         [0004]    2. Discussion of the Known Art 
         [0005]    Traumatic separation of the acromioclavicular (AC) joint is common, particularly among athletes. Complete rupture of the coracoclavicular ligament is common in the more severe grades of injury (type 3 or greater). Although surgical techniques for repairing or reconstructing the ligament have evolved over the last several decades, a gold standard has not yet emerged. 
         [0006]    The proper course of initial treatment of an acute type 3 separation of the AC joint remains controversial. Although studies have demonstrated successful outcomes with nonoperative treatment, others have noted poor outcomes in over 40% of patients. Many of these patients have subsequent surgical treatment for ongoing symptoms of both pain and/or weakness. Long-term follow-up has shown residual symptoms in most patients treated nonoperatively. This has led to a commonly accepted recommendation of surgical treatment in high-level athletes or high-demand manual laborers. But even among patients with lower demand levels, a recent study has shown a poor outcome in 20% of non-athletes, and an additional 15% of patients reported significant symptoms of weakness. 
         [0007]    The weight of the arm places a constant deforming force on a surgical fixation construct during biologic healing. In the acute setting, there is a robust healing response after ligament rupture, and additional grafting may not be necessary as long as the initial fixation can remain stable during the healing process. In the chronic setting, it is necessary to add biologic graft material to the fixation construct to ensure long-term stability and function. During the healing process, graft material is likely to weaken and stretch during the course of revascularization. Thus, when a fixation device is used in conjunction with a graft, it is at risk for implant failure if the graft deforms and stretches. 
         [0008]    Surgical treatment has shown higher success rates in recent studies, but many of the techniques have become associated with significant implant related complications. Failure to establish a treatment with a reproducible outcome and a consistently low complication rate has therefore led most sports medicine specialists to continue to recommend non-operative management for the initial treatment of type 3 AC joint separations. For example, in a recent survey of over 500 members of the American Orthopaedic Society for Sports Medicine, more than 80% of respondents preferred non-operative treatment for initial management. 
         [0009]    Prior techniques using various forms of hardware fixation, such as the Bosworth screw, have fallen out of favor because of hardware failures and the need for a second procedure to remove the hardware. The Weaver-Dunn procedure, first described in 1972, avoids the use of metallic implants and continues to be popular notwithstanding an originally reported failure rate of 28% in a small series of 15 patients. Attempts to improve the original Weaver-Dunn technique have involved various methods of non-metallic fixation to stabilize the AC joint. Notwithstanding the success of these methods, implant-related problems including infection, soft tissue reactivity, and fractures have been identified. These implant-related problems have led to development of purely biologic constructs that use allograft or autograft to reconstruct the coracoclavicular complex. 
         [0010]    Biomechanical studies have yielded techniques for re-creating the native anatomy more accurately, and finding materials that can tolerate cyclic loading without deformation or failure. The ultimate strength, stiffness, and load elongation curves of the native complex have been measured against various repair constructs, and testing has been performed with both simple load to failure modes as well as response to cyclical loading to simulate postoperative conditions. Traditional procedures like Weaver-Dunn have been shown to be much weaker and more compliant than the native ligament, thereby explaining the frequently observed high failure rate of that procedure. A common modification involves stabilizing the joint by placing a cerclage material around the base of the coracoid and through a hole in the clavicle. Thick, robust materials such as polidioxanone bands or large tendon grafts have shown comparable strength relative to the native complex; however, their load-elongation curves indicate lower stiffness in most of the tested materials. Significantly, cerclage techniques have also been found to be non-anatomical as the fixation method drags the distal clavicle anteriorly. One study showed that even when the drill hole is placed within 2 mm of the anterior edge of the clavicle, the clavicle is pulled anteriorly. This malreduction is likely to lead to abnormal forces placed on the construct, weakening the construct with time as cyclical forces act on it constantly during the healing process. 
         [0011]    Fixation placed in anatomically correct positions should improve implant stability and response to cyclical loads. Techniques have been described that achieve stability by placing grafts or fixation devices through anatomically placed boles in the clavicle and coracoid. An ideal procedure would use a fixation construct that not only restores the normal biomechanics of the ligament complex, but also maintains reduction throughout the biologic healing process. 
         [0012]    U.S. Pat. No. 5,645,588 (Jul. 8, 1997), incorporated by reference, shows a graft attachment device for use arthroscopically to reconstruct the anterior cruciate ligament (ACL) in the knee. The device has a rectangular, bar-shaped body of stainless steel or equivalent biocompatible material, 4 mm in width and 12 mm in length. A first pair of 0.062 inch diameter openings are formed near the opposite long ends of the device body, and a second pair of 0.78 inch diameter openings are formed along the long direction of the device body between the first pair of openings. A patellar tendon graft is linked to the device by two sutures both of which pass through the second pair of openings in the device, and the free ends of each suture are tied so that sutures form closed loops. Each one of a second pair of sutures passes through a corresponding one of the first pair of openings, and the free ends of the second pair are threaded through a slot at the end of a pin instrument that has been inserted though passages formed in the femur and the tibia. The device, together with the graft which is linked to the device, are pulled through the passages by the pin instrument until the device emerges from a passage at the upper femoral cortex. The device is then rotated and seated against the femoral cortex. See also U.S. Pat. No. 6,533,802 (Mar. 18, 2003), and U.S. Pat. No. 5,041,129 (Aug. 20, 1991), both of which are incorporated by reference. 
       SUMMARY OF THE INVENTION 
       [0013]    According to the invention, a surgical fastener system for treatment of acromioclavicular (AC) joint dislocations, includes a first fastener including an elongate body having an outer pair of openings formed in the vicinity of opposite ends of the body, and an inner pair of openings formed between the outer pair. A portion of a closed loop stitch passes through the inner pair of openings, and the loop stitch has a length that corresponds to a measured depth of a passage defined between a top opening of a first hole bored through a patient&#39;s clavicle, and a bottom opening of a second hole bored through the coracoid in axial alignment with the first hole. A second fastener includes an elongate body having at least an outer pair of openings formed in the vicinity of opposite ends of the body. The body of the second fastener is dimensioned and arranged to be slid through a portion of the closed loop stitch that protrudes from the top opening of the first hole in the clavicle, after the first fastener is set beneath the coracoid and the loop stitch is pulled upward through the passage between the top opening of the first hole and the bottom opening of the second hole. 
         [0014]    According to another aspect of the invention, the body of the second fastener also has an inner pair of openings for passing and engaging the loop stitch. 
         [0015]    For a better understanding of the invention, reference is made to the following description taken in conjunction with the accompanying drawing and the appended claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0016]    In the drawing: 
           [0017]      FIG. 1  shows an acromioclavicular joint being prepared for treatment with the inventive fastener system; 
           [0018]      FIG. 2  shows a first fastener arranged with a lop stitch according to one embodiment of the inventive system; 
           [0019]      FIG. 3  shows the fastener in  FIG. 2  inserted through holes that are bored in the clavicle and the coracoid in the joint in  FIG. 1 ; 
           [0020]      FIG. 4  shows the loop stitch pulled upward through the bored holes after the first fastener is set beneath the coracoid, and a second fastener is slid through a portion of the stitch that protrudes atop the clavicle; 
           [0021]      FIG. 5  shows the second fastener set in place atop the clavicle; 
           [0022]      FIG. 6  shows the loop stitch locked in place about the body of the second fastener, and a suture tied to the clavicle through another hole bored in the clavicle; 
           [0023]      FIG. 7  shows another embodiment of the inventive fastener system, wherein the bodies of first and second fasteners are linked by a common closed loop stitch; 
           [0024]      FIGS. 8 and 9  show the fasteners in  FIG. 7  aligned for entry into and through the holes bored in the clavicle and the coracoid; 
           [0025]      FIG. 10  shows a first one of the fasteners in  FIG. 7  set beneath the coracoid; 
           [0026]      FIG. 11  shows the second fastener in  FIG. 7  being withdrawn from the hole in the clavicle after the first fastener is set beneath the coracoid; and 
           [0027]      FIG. 12  shows the second fastener set in place atop the clavicle. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0028]      FIGS. 1 to 6  illustrate a surgical procedure for treatment of an AC joint dislocation, using a first embodiment of a fastener system according to the invention. In  FIG. 1 , a 2-inch incision is made from the palpable base of the tip of the coracoid  12 , to the anterior edge of the distal clavicle  14 . Medial and lateral skin flaps are developed. The deltoid is split in line with its fibers, and the coracoid  12  is identified and cleared off all the way to the base. The medial and the lateral edges of the coracoid  12  at the base are clearly identified. 
         [0029]    The clavicle  14  is manually reduced, and while the reduction is being held, a drill tip guide wire  16  is drilled into the top of the clavicle  14  approximately 3 cm medial to the AC joint  18 , and midway between the anterior and the posterior border of the clavicle. The drill hole should be directly over the base of the coracoid  12 , and the drill wire  16  should be aimed slightly anteriorly. After drilling through the clavicle  14 , the wire  16  should be easily visualized in between the clavicle and the coracoid  16 . Once the tip of the wire  16  is confirmed to be entering the coracoid  12  well centered between the medial and the lateral edges, it as then drilled all the way through and out the base. 
         [0030]    A 4.5 mm dia. drill  22  is guided over the drill guide wire  16  to bore a first hole  24  through the clavicle  14 , and another hole  26  (see  FIG. 2 ) through the coracoid  12  in alignment with the clavicle hole  24 . With the clavicle  14  well reduced, a depth gauge (not shown) is used to measure the length of a passage from the top opening of the bore hole  24  in the clavicle, to the bottom opening of the bore hole  26  in the coracoid. A 2.5 millimeter dia. drill hole  28  is bored in the clavicle  14 , one cm lateral to the top of hole  24 . 
         [0031]    A fastener  50  arranged according to the invention is shown in  FIG. 2 . The fastener  50  includes a sturdy elongate body  52  formed of surgical steel or an equivalent medically safe material. The fastener body  52  may measure, e.g., approx. 4 mm wide by 12 mm long. An outer pair of openings  54   a,    54   b  are formed near the opposite short side ends of the fastener body  52 , and an inner pair of openings  56   a,    56   b  are centered on the long axis of the body  52  between the outer pair of openings  54   a,    54   b.  An endless or closed loop stitch  58  engages the fastener  50  by passing through inner openings  56   a,    56   b  in the fastener body  52 . The stitch  58  may be formed, for example, by tying the ends of a suture strand together to form a loop whose length corresponds to that measured by the depth gauge noted above. The fastener body  52  with the closed loop stitch  58  may also be obtained from Smith &amp; Nephew, Inc., of Memphis, Tenn. under the mark EndoButton®, or from ConMed of Largo, Fla. under the mark “XO Button”. 
         [0032]    As seen in  FIG. 2 , two number 5 Ethibond (or similar) sutures  60 ,  62  are placed through the outer pair of openings  54   a,    54   b  in the body  52  of the fastener  50 . A third suture  64  is passed through the apex of the loop suture  58  of the fastener  50 . The suture  64  is preferably well marked so it can be used to identify the loop suture  58  through which it passes. 
         [0033]    The fastener  50  with its associated sutures  60 ,  62 ,  64  are vertically oriented and urged through the top of the clavicle  14  through the hole  24 , using a 3.2-mm smooth cylindrical plunger  70 . The fastener  50  is visualized in the space between clavicle  14  and coracoid  12 , and it is pushed further to enter the coracoid hole  26  until the fastener “pops” out from the underside of the coracoid  12  as seen in  FIG. 4 . Then, by pulling the loop stitch  58  upward via the suture  64 , the fastener  50  assumes the horizontal position in  FIG. 4  to lock onto the underside of the coracoid  12 . A pair of tails of one of the remaining sutures, e.g., suture  62 , are pulled out of the interval between the coracoid  12  and the clavicle  14 . This leaves the tails of one suture, e.g., suture  60  that is looped to the fastener body  52 , available to exit from the top of the hole  24  in the clavicle  14  as shown in  FIG. 3 . With firm downward pressure on the clavicle  14  to maintain maximum reduction, the loop stitch  58  is pulled up through the hole  24 . With a very firm upward pull on the loop stitch  58 , the upper tip of the loop stitch will then protrude from the top of the clavicular hole  24 . 
         [0034]    In  FIG. 4 , a second button fastener body  152  which may be similar or identical in form to the fastener body  52  in  FIG. 2 , is held with a suture holder  70  and slid horizontally through the protruding loop of the stitch  58  until the body  152  is centered under the loop. It is preferred that the fastener body  152  be held with its long edge facing the clavicle  14 , rather than lie flat against the bone. The suture tails  60  exiting the hole  24  at the top of the clavicle, are passed through a pair of openings formed near the opposite ends of the body  152 . If the body  152  is formed with inner and outer pairs of openings like the fastener body  52 , it is preferred to pass the suture tails  60  through the outer pair of openings as shown in  FIG. 4 . 
         [0035]    The button fastener body  152  is turned with the suture holder  70  so it lies flat on the clavicle  14 , so that the suture tails  60  exit upward from the openings in the body  152  as shown in  FIG. 5 . Suture  64  is withdrawn, and the suture tails  60  are tied across the top of the loop stitch  58  as shown in  FIG. 6 . This locks the stitch  58  in place and completes the reconstruction of the conoid portion of the coracoclavicular ligament. The suture tails  62  that were brought out of the coracoclavicular space are retrieved. One of the tails  62  is passed through the  2 . 5  mm drill hole  28  from beneath the clavicle  14 , and the ends of the suture tails are tied at or near the top of the hole  28 . This recreates the trapezoid portion of the coracoclavicular ligament. 
         [0036]    A fastener device  200  according to the invention is shown in  FIG. 7 . The device  200  includes two fastener bodies  252   a,    252   b  each of which may be similar or identical in form to the fastener body  52  in  FIG. 2 . The fastener bodies  252   a,    252   b  are linked by one endless or continuous loop  258  which passes through pairs of openings  256   a,    256   b  formed in each of the bodies. Like the fastener body  52  in the first embodiment, at least the body  252   b  at the top of  FIG. 7  also has an outer pair of openings  254   a,    254   b  formed near the opposite ends of the body. 
         [0037]    Using the fastener device  200  of  FIG. 7 , the surgical procedure described above can be modified by threading two sutures  210 ,  212  through the outer openings  254   a,    254   b  at opposite ends of the fastener body  252   b  at the top of  FIG. 7 . As depicted in  FIGS. 8 and 9  the two fastener bodies  252   a,    252   b  are oriented vertically in line with one another, and body  252   a  at the bottom of the loop  258  is fully inserted into the top of the hole  24  in the clavicle  14 . Fastener body  252   b  is then inserted into the top of the hole  24  and urged downward with a plunger or other suitable tool so that the leading end of the body  252   b  advances the body  252   a  downward through the hole  24  to enter the top of the opening  26  at the top of the coracoid  12 . The body  252   a  is then advanced further through the opening  26  until it fully exits the opening at the underside of the coracoid  12 . Then, by pulling the sutures  210 ,  212  on the fastener body  252   b  upward, the fastener body  252   a  assumes a horizontal position in  FIG. 10  to lock onto the underside of the coracoid  12 . 
         [0038]    When the joint is fully reduced as depicted in  FIG. 11  the sutures  210 ,  212  are pulled upward until the fastener body  252   b  exits the clavicular hole  24  as shown in the figure. Then by pulling upward on the suture  212  as represented in  FIG. 12 , the fastener body  252   a  is swivelled horizontally to lie flat on the surface of the clavicle  14  and thereby lock the joint reduction in place. 
         [0039]    The fastener device  200  of  FIG. 7  has an advantage over the fastener  50  of  FIG. 2 , by eliminating those steps in  FIGS. 4 ,  5  and  6  wherein a second, free fastener body  152  is needed to be inserted through the top of the loop  58 , and the suture  60  is tied so as to lock the fastener body  152  in place on the surface of the clavicle  14 . 
         [0040]    Fasteners as disclosed herein have been used successfully in cases of chronic type 3 or 4 AC separations. The fasteners are set in an anatomically correct fashion to reproduce the course of the conoid portion of the coracoclavicular ligament. The strength and stiffness of the fasteners have been proven to exceed the native ligament complex by approximately 40%. Deforming forces due to the weight of the arm are distributed along the surfaces of the fasteners rather than the suture material itself which passes through the openings in the fasteners, thereby minimizing the chance of a soft tissue reaction to the suture material. The sutures  62 , which may be threaded through openings in the fastener bodies, can be used to recreate the course of the trapezoid component of the coracoclavicular ligament and add stability in the anteroposterior plane. 
         [0041]    In addition, the required drill holes are relatively small (e.g., approx. 4 mm or less), allowing the implant to be used either as a stand-alone device or in conjunction with other biologic implants to improve long-term stability. Forming the suture material in a continuous loop eliminates problems of knot slippage associated with other types of suture fixation. The procedure is straightforward and requires only a small incision with minimal soft tissue dissection. 
         [0042]    The inventive fasteners  50 ,  200  allow a knotless fixation to be obtained for repair and/or reconstruction of the shoulder coracoclavicular ligament, with reliable and predictable results. The fasteners are inserted through holes bored in the clavicle and the coracoid to reproduce the normal course of the conoid portion of the coracoclavicular ligament. The fasteners may be used alone or in conjunction with a variety of biologic materials depending on whether surgery is being performed in an acute or a chronic setting. 
         [0043]    While the foregoing represents preferred embodiments of the invention, it will be understood by those skilled in the art that various modifications and changes may be made without departing from the spirit and scope of the invention, and that the invention includes all such modifications and changes as come within the bounds of the following claims.