Abstract:
An elongated drill and suture guide is inserted through a posterior portal during arthroscopic surgery to repair a Bankart lesion of a human shoulder. The drill and suture guide has a linear longitudinal bore for a drill pin effective to bore through the glenoid rim of the shoulder joint. With the drill and suture guide held stationary, the drill pin is removed and a suture passer is inserted through the bore of the guide and through the hole in the glenoid rim, then through the detached glenoid labrum which may be held by a tissue grasper in the anatomically correct location by way of an anterior portal. The suture is manipulated and tied conventionally to secure the glenoid labrum in approximately its anatomically correct position, whereupon the drill and suture guide is reinserted for repeating the procedure at another location along the lesion.

Description:
FIELD OF THE INVENTION 
     The present invention relates to the general field of orthopedic instrumentation. More specifically, the present invention relates to an instrument and method for repairing a detachment of connective tissue between the ball and socket of the shoulder joint along the anterior (front) and inferior (lower) margin of the glenoid cavity. Such detachment is commonly known as a Bankart lesion. 
     BACKGROUND OF THE INVENTION 
     The human shoulder articulates about a loose fitting ball-and-socket joint which allows extremely free movement of the arm relative to the trunk. The ball is formed on the head of the humerus (the upper arm bone), and the socket is formed by the shallow, laterally opening glenoid cavity of the scapula (the flat triangular bone in the back of the shoulder). The depth of the socket is increased by a circumferential ring of fibrocartilage, the glenoid labrum, to which the head of the humerus is attached by an encircling mass of connective tissue called the articular capsule. Such capsule includes ligaments and tendons, for example. 
     There is little area of contact between the ball of the humerus and the glenoid cavity at any time. There always is a considerable part of the ball in contact with the articular capsule. The loose connection allows the articulating surfaces of the bones to be separated substantially. The joint is dependent for its integrity on the surrounding muscles. The joint is so loosely constructed that it is frequently dislocated, particularly by athletes participating in throwing or racquet sports. 
     There is greater superior (upper) and posterior (rearward) support for the shoulder joint so that it invariably dislocates in an anterior (forward) and inferior (downward) direction. The result is avulsion of the glenoid labrum from the anterior and inferior margins of the glenoid cavity, known as a Bankart lesion. A Bankart lesion can be detected by measuring the range of motion and verifying anterior instability of the shoulder joint. 
     Nonoperative treatment of anterior shoulder instability is rarely successful, but surgical repair almost always restores stability to the glenohumeral joint. Open shoulder surgery involves spreading the muscles overlying the anterior side of the joint and severing some of the connective tissue to provide access to the anterior glenoid rim. Typically, frayed tissue is resected and all tissue remnants attached to the anterior glenoid rim are debrided. The exposed bone is abraded. In one technique, intersecting holes are drilled in the anterior and lateral faces of the glenoid adjacent to the rim for sutures which secure the detached labrum firmly to the glenoid at two or three locations. Over time the labrum reattaches. 
     Arthroscopic surgery also is performed for repairing a Bankart lesion. Preparation of the glenoid rim to reduce it to a raw bleeding surface is essentially the same as for open surgery, but different techniques for securing the labrum to the glenoid area are used. In one technique, one or more staples are used to connect the glenoid labrum to the anterior side of the scapular neck medially of the glenoid cavity. In another technique, the labrum is impaled with a rivet which then is driven into the scapular neck. In another technique, blind bores are drilled adjacent to the anterior glenoid rim for specially designed suture anchors. In another technique, a hole is drilled through the scapular neck for suture material or for pins or screws to which suture material can be attached. 
     Often, full glenohumeral motion and, in the case of an athlete, performance are sacrificed for the stability restored by surgery. It is believed that one reason for inadequate stability, decreased motion and decreased performance is that the glenoid labrum is not secured at the anatomically correct location by use of known instruments and procedures. In some of the known techniques the labrum is secured to a single location such as an anchor member in the anterior side of the scapular neck, and in other known procedures the labrum is attached at two or three locations along only the anterior portion of the glenoid rim. Nevertheless, dislocation of the shoulder joint will tear the glenoid labrum from the inferior rim, as well as the anterior rim. Access to the inferior glenoid rim is limited, particularly during arthroscopic surgery. There is no known arthroscopic system that allows securing the labrum directly to the inferior glenoid rim, in addition to securing it along the anterior rim, so that the labrum will reattach in the correct position. 
     SUMMARY OF THE INVENTION 
     The present invention provides a system for repair of Bankart lesions to correct anterior shoulder instability. The system uses a novel orthopedic instrument in the form of an elongated drill and suture guide which may be inserted during arthroscopic surgery such that a recess on the distal end of the guide fits over the glenoid rim in the area of the lesion. Unlike traditional arthroscopic shoulder surgery in which access to the glenoid rim is from the front, the instrument is inserted through a posterior portal and then between the ball of the humerus and the glenoid cavity so that access to both the anterior and inferior glenoid rim is possible. the instrument has a linear longitudinal bore opening into the distal recess for a drill pin effective to bore through the glenoid rim by bridging across the recess. With the instrument held stationarily, the drill pin is removed and a suture passer is inserted through the bore of the instrument and through the hole in the glenoid rim, then through the detached glenoid labrum which may be held by a tissue grasper in the anatomically correct location by way of an anterior portal. Alternatively, a hooked suture guide is used to penetrate the labrum at the desired location and convey suture material from the suture passer through the labrum. Thereafter, the suture is manipulated and tied conventionally to secure the glenoid labrum in approximately its anatomically correct position, whereupon the drill and suture guide is reinserted for repeating the procedure at another location along the lesion. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein: 
     FIG. 1 is a top perspective of instruments used in a system for repairing Bankart lesions in accordance with the present invention including a conventional drill pin, a conventional suture passer, and a novel drill and suture guide for the conventional pin and passer. 
     FIG. 2 is a side elevation of the drill and suture guide of FIG. 1. 
     FIG. 3 is a bottom plan of the drill and suture guide of FIG. 1. 
     FIG. 4 is a proximate end elevation of the drill and suture guide of FIG. 1. 
     FIG. 5 is an enlarged bottom perspective of the distal end portion of the drill and suture guide of FIG. 1. 
     FIG. 6 is a transverse section along line 6--6 of FIG. 3. 
     FIG. 7 is a somewhat diagrammatic perspective of a shoulder joint during arthroscopic surgery looking generally medially and posteriorly toward the glenoid cavity with the humerus and other body parts deleted; FIG. 8 is an enlarged perspective looking generally medially and superiorly of such joint illustrating one step of the system in accordance with the present invention; and FIG. 9 is a perspective of such joint corresponding to FIG. 8 but illustrating another step of such system. 
     FIG. 10 (on the drawing sheet with FIG. 7) is an enlarged longitudinal section of the distal end portion of the suture passer shown in FIG. 1. 
     FIG. 11 is a top perspective of a novel suture guide that can be used in the system of the present invention. 
     FIG. 12 is a perspective corresponding to FIG. 7 illustrating use of the suture guide of FIG. 11. 
     FIG. 13 is an enlarged detail of the distal end portion of the suture guide of FIG. 11 during use, with parts broken away and parts shown in section. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The system in accordance with the present invention is used to repair a Bankart lesion, i.e., to secure the fibrocartilage periphery known as the glenoid labrum to the glenoid rim at approximately the anatomically correct location after the labrum has been torn from the rim by dislocation of the shoulder joint. Instruments used in the system in accordance with the present invention are shown in FIG. 1 and include a novel drill and suture guide 10 having a longitudinally extending bore for receiving a conventional drill pin 11 or a novel suture passer 12. Pin 11 has a sharpened distal end 13 and a proximate end (not shown) for fitting in the chuck of a conventional drill. 
     Suture passer 12 has a longitudinal bore communicating with a side port 14 adjacent to the solid pointed distal end 15 of the suture passer. The other end of the bore opens through the proximate end of the passer. The proximate end portion 16 is enlarged and has a knurled surface for ease in manipulation of the passer. The enlarged proximate end portion 16 has a longitudinally extending flattened portion 17 registered axially with the side port 14 so that the user always knows the direction of opening of the side port. 
     The drill pin 11 and suture passer 12, except for the enlarged proximate end portion 16 of the suture passer, are of a diameter small enough to pass through the bore of the drill and suture guide 10. 
     With reference to FIGS. 2 through 6, the drill and suture guide 10 in accordance with the present invention is an elongated shaft having a proximate handle end portion 20 which preferably is knurled and includes a short radially extending tab 21 for ease in holding and manipulating the instrument. From the tab forward, the maximum diameter of the shaft is sufficiently small so as to fit through a standard arthroscopic sleeve, preferably no greater than about 5 to 6 mm. For use in the present invention, the shaft can be about seven inches long. 
     Except for the radially extending tab 21, the shaft is substantially cylindrical throughout the major portion of its length, from the proximate end portion 20 toward the distal or working end portion 22. However, as seen in FIG. 1 and FIG. 2, the upper surface of the distal end portion of the instrument is flattened and curved gradually upward from the cylindrical proximate and central portions of the shaft. As seen in FIG. 6, the flattened distal top surface 23 also is preferably slightly concave in cross section. 
     The distal tip of the instrument is formed by a short flange 24 inclined downward from the top of the shaft. Just proximate to the flange, the end of the instrument is beveled to form an upward inclined surface 25 facing the downward inclined surface 26 of the flange 24. Such surfaces meet at an abrupt corner 27 extending transversely of the instrument. Preferably, the beveled surface 25 makes a small acute angle of about 30 relative to the center line of the instrument, whereas the inner surface of the flange makes a greater acute angle of about 40 to 45 relative to the center line of the instrument. Consequently, the angle between the planar facing surfaces is obtuse, preferably about 110°. In the preferred embodiment, the flange 24 is about 4 mm long and about 2 mm thick, so that the lower tip of the flange is positioned at or slightly below the center line of the shaft of the instrument. 
     The shaft of the drill and suture guide has a linear through bore 30, which preferably is about 2 mm in diameter. Bore 30 extends obliquely relative to the center line of the instrument, starting at a location offset upward from the center of the instrument at the distal end, as seen in FIG. 4, and ending at a location offset downward from the center line of the instrument as seen in FIG. 5 and FIG. 6. The distal end of bore 30 opens closely adjacent to the bottom of the beveled surface 25. The axis of the bore traverses the recess defined by the facing surfaces 25 and 26 and passes just beneath the bottom tip of the flange 24. As seen in FIG. 5, the bottom tip of flange 24 can have a central notch 31, so as not to interfere with extension of the drill pin or suture passer through the bore 30 and across and beyond the recess. 
     FIG. 7 illustrates the anatomy in the area of a Bankart lesion repairable by use of the system in accordance with the present invention. The scapular side of the shoulder joint is illustrated as viewed in a medial direction with the humerus and other adjacent tissue deleted. The shallow glenoid cavity 40 is normally encircled by the articular capsule 41 of connective tissue attached at the margin of the cavity by the glenoid labrum 42. In the case of shoulder dislocation, a Bankart lesion results where the labrum is torn from the anterior rim 43 and inferior rim 44. 
     For arthroscopic viewing of the affected area, a generally downward-directed portal is opened just anterior to the supraspinatus tendon for a conventional cannula 45. Another anterior portal is opened for a cannula 46 passing just above the upper border of the subscapularis tendon, lateral to the middle glenohumeral ligament. Cannula 46 provides access to the area of the lesion for conventional instruments, such as a tissue grasper 47. A posterior portal is opened for a generally forward-directed cannula 48 at a location just inferior to the postero-lateral corner of the acromion 49. The forwarded-directed cannula 48 provides access to the affected area by the drill and suture guide 10 in accordance with the present invention. 
     As is conventional, frayed tissue obscuring arthroscopic viewing of the labrum and glenoid rim is resected. All tissue remnants attached to the glenoid rim in the area of the tear are debrided so that the bone of the rim is exposed adjacent to the separated labrum. A burr and/or rasp is used to abrade the inner and outer margins of the glenoid rim. The resection, debriding and abrading all are under direct arthroscopic visualization and can be accomplished by access through the posterior portal as well as through the anterior portals. 
     Next, the drill and suture guide 10 is inserted through the posterior portal and is positioned with its distal flange 24 hooked over the raw bony surface of the inferior glenoid rim. The beveled distal surface of the instrument through which its bore opens is placed flat against the rim, which helps to stabilize the instrument. In addition, the flattened and preferably concave upper surface 23 is engaged by the adjacent ball of the humerus which presses against the top of the instrument and helps to maintain it stably in position. If the distal end portion of the upper surface of the instrument were cylindrical, as is the majority of the shaft, localized pressure would be applied against the articular cartilage of the humeral ball which could damage the cartilage and dislodge the instrument. 
     With reference to FIG. 8, with the drill and suture guide 10 held firmly in position as described above, a section of the separated labrum is grasped and held against the glenoid rim in approximately the anatomically correct position. The drill pin 11 is inserted through the bore of guide 10. Conventional external drilling equipment is used to rotate and advance the drill pin linearly through the margin of the bone from inside the glenoid cavity to the anterior side of the bone just below the rim. The drill pin passes just below the bottom of the flange 24 through its central notch, as represented in FIG. 5. 
     The drill pin 11 is removed and, without changing the position of the guide 10, the suture passer 12 is inserted through the bore of the guide so as to pass through the newly-drilled hole in the glenoid rim. Suture material 52 is threaded through the bore of the passer so that an end of the suture material projects from the side port 14 as seen in FIG. 9. With reference to FIG. 10, the tip 50 of the suture passer 12 is solid and pointed, and the bore 51 of the suture passer curves gradually outward to the side port 14 which is of a length substantially greater than the diameter of the straight portion of the bore for free passage of the end of the suture material through the side port. Such suture end can be grasped by an appropriate implement fed through the inferior anterior portal, whereupon the suture passer and guide 10 can be retracted from the posterior portal. If the appropriate part of the labrum cannot be penetrated by the suture passer, a conventional suture hook can be used. A grasping implement then is inserted through the posterior portal to retrieve the loose end of suture material and bring it to the exterior of the posterior cannula for tying of a conventional fisherman&#39;s knot (slip knot) which then is advanced back through the posterior portal by a conventional knot pusher and tightened to secure the labrum in the approximate anatomically correct position. 
     It can be difficult to suture the labrum at the desired location using the instruments described above. An alternative is to use a special suture guide of the type illustrated in FIG. 11 with a conventional suture passer of the type having an exit port in its distal end in line with the bore of the suture passer. The special suture guide 60 has an elongated central shank 61 extending from an angular handle 62 forming the proximate end portion of the guide. The shank leads to a pig-tailed distal end portion 63, including at least one full generally helical loop 64. The pig-tailed portion of the guide has a central bore opening at the distal end 65, and extending proximally through the helical loop to a circumferential outlet port 66. 
     The apertured distal end 65 of the pig-tailed suture guide 60 is sharpened. The distal end portion and central shank of the guide are of a maximum diameter no greater than about 6 mm so that they can be fitted through the anterior inferior cannula 46 as illustrated in FIG. 12. Such sharpened distal end can be manipulated to penetrate the labrum at the desired anatomically correct location with the aperture of the distal end exposed adjacent to the straight suture passer 12&#39;. As illustrated in FIG. 13, the suture passer 12&#39; and pig-tailed suture guide 60 are positioned such that the distal end portion of the suture passer is received in the distal end 65 of the suture guide. The labrum and connective capsular tissue attached to it are hooked in the loop 64 of the helix of the guide. Suture material 52 then can be passed through the straight bore of the passer 12&#39; into the curved bore of the guide 60 such that the suture material is conveyed through the labrum and out through the circumferential port 66 of the guide. The guide then is removed from the inferior anterior cannula, leaving the inner end portion of the suture material exposed for grasping implements. The suture material is brought to the exterior of the posterior cannula for tying, knot-pushing and tightening, as described above. 
     With reference to FIG. 7, regardless of the suturing system used, the procedure of securing the separated labrum to the prepared raw bony surface of the glenoid rim is repeated at higher locations all the way up to and including the anterior portion 43 of the rim, as represented in broken lines in FIG. 7. Consequently, substantially the full extent of the labrum can be secured at the anatomically correct position. In comparison, previous arthroscopic repair techniques rely on access to the glenoid cavity from the front and do not secure the separated labrum directly to the inferior rim 44. Some techniques are more anatomically correct than others, such as those which secure the labrum at several locations along the length of the anterior rim with implantable anchors as compared to those which secure the labrum only to one or two locations in the scapular neck medially of the glenoid cavity. Nevertheless, no prior method is known which allows direct securing of the inferior portion of the labrum to the inferior glenoid rim and, more particularly, securing the inferior labrum by suturing without staples, screws or anchoring members of metal or other foreign material. When the labrum cartilage reattaches to the glenoid rim, the glenohumeral connective tissue in the anatomically correct position, including ligaments and tendons, should reduce the chance of recurrent instability in addition to permitting a more natural range of motion and performance close to that experienced prior to dislocation of the shoulder. 
     While the preferred embodiment of the invention has been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.