Abstract:
An anatomical shoulder fixation system comprises a lower portion and an upper portion, the lower portion being a separate part and being coupled to the upper portion adjustably. For example, the relative position of the upper portion to the fixation system is capable of rotating and translating with relation to the lower part, accommodating placement on a shoulder even if displacement of the lesser tuberosity and the greater tuberosity due to fracture or dislocation. Examples include a flexible upper portion coupled to a lower portion or a more rigid upper portion joined to a lower portion, and combinations of these. In both examples, screws may be used to fix the lower portion prior to completing the displacement and fixation of the upper portion. For example, the lower portion may provide structures for attaching sutures, suitable for use with a curved needle shaft and suture.

Description:
CROSS RELATED APPLICATIONS 
     This application claims priority to the filing date of U.S. Provisional Appl. No. 61/801,675, which was filed on Mar. 15, 2013, the specification and drawings of which are hereby incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The field relates to implantable medical devices for orthopedics, especially for shoulder fixation devices and methods. 
     BACKGROUND 
       FIG. 1  illustrates a known fixture for repairing a fracture of a shoulder that uses a plurality of screws, pins and the like to fix a fractured shoulder bone. U.S. Pat. No. 4,463,753 discloses a bone screw for compressing a fracture. Also, it is known how to make the angle of screws adjustable in a one-piece, solid fixation device, such that the angle of the screws may be adjusted relative to the fixation device. None of the known devices are capable of articulated repositioning of an upper and lower portion of the fixation device. 
     SUMMARY 
     An anatomical fixture system and method comprises a lower portion, such as a stem, and an upper portion, such as plate, angled portion or leaf capable of anchoring soft tissues to bone and/or repairing fractures in bone. For example, the anatomical fixture system is used for repairing humeral damage, such as humeral fractures and/or rotator cuff damage caused by torn or severed soft tissues, such as tendons, ligaments and muscles. Screws may be used to fix a lower portion on the bone, and an upper portion may be attached by sutures or screws. 
     In one example, an anatomical fixation system comprises an upper portion coupled with the greater tuberosity and a lower portion coupled with the lesser tuberosity of the humeral head  11 . An arm or wings may be provided. For example the arm or wings may be detachable from the lower portion or the upper portion. A plurality of screws or other fixation devices may be used to secure the lower portion and/or upper portion onto the bone. In one example, a locking mechanism may be provided that adjustably locks the upper portion in relation to the lower portion. For example, the locking mechanism may comprise a bolt capable of coupling the upper portion to the lower portion. For example, the lower portion may be fixed to the bone using one or more screws, and the upper portion may be adjustably coupled to the lower portion by loosely attaching the upper portion to the lower portion with the locking mechanism. Then, the upper portion may be fixed to the humeral head using screws and/or sutures and/or pins as is known in the art. 
     In one example, the locking mechanism is paired with an adjusting mechanism, such that a fractured head may be repositioned by adjusting the position of the upper portion in relation to the lower portion. Then the locking mechanism may be tightened locking the position of the upper portion in relation to the lower portion of the fixture. The locking mechanism may comprise an element that is bioabsorbable, such that the locking mechanism becomes less effective over time, allowing stress to be accommodated by the anatomical fixture system, initially, and by the bone and soft tissues, eventually, when the bioabsorbable element is partially or fully bioabsorbed. By choosing a bioabsorbable polymer, such as polylactides or other known bioabsorbable polymers, and the dimensions of the bioabsorbable element of the locking mechanism, the system may provide for an extended but not indefinite period for the bone to begin to heal before too much stress is transferred from the system back to the bone. Preferably, the load on the bone and soft tissues is gradually transferred until the bone and soft tissues are healed and become capable of bearing the entire load or a substantial portion of the entire load. 
     In one example, cut-outs and channels are formed that avoid anatomical features, such as tendons and blood vessels. In one example, a threaded receptacle and a threaded positioner are capable of matingly threading together, such that one portion of the system is angularly displaceable relative to another portion. For example, one portion may be angularly displaced in a plurality of angular directions including arcuately side-to-side and forward-and-back. In one example, the different portions may be translated along a distance and angularly positioned. In yet another example, one portion may be made of a flexible material or a flexible, elastic material capable of freely conforming to anatomical shapes while providing a tensile or tensile elastic stress from a portion where the flexible material is coupled to a rigid fixation system attached to the bone. For example, a lower portion may be a rigid stem fixed to a bone by screws, and a flexible upper portion, such as a leaf, may be coupled to an anchor of the lower portion. The upper portion may be made of a material that readily deforms, such as mesh or patch made of a film or fabric, but the material may be capable of withstanding substantial tensile stresses. In one example, a leaf may be comprised of a film or mesh reinforced by fibers or filaments extending along a length of the material. As is known in the art, such a material may take up substantial tensile stresses without failure, while remaining thin. In one example, such a material comprises a bioabsorbable material capable of being bioabsorbed over time by a human body, when the material is implanted into the body. Such materials are known in the art to include biological tissues and synthetic tissues. A very early bioabsorbable material known in the art is sutures made of cat gut or other such biological tissues. There are many polymers and copolymers capable of being bioabsorbed and the number increases each year. 
     In one example, a system may be fabricated using 3-D printer technology to provide a custom fit to a patient based on 3-D imaging of the patients humeral bone and imaging of tendons. For example, both the fractured humeral bone and the opposite unfractured humeral bone may be imaged to reconstruct how the system will be formed and adjusted to return the fractured pieces of the humeral bone to a location as close as possible to the anatomical location of the pieces prior to injury. Thus, the system may be anatomically formed to fit the bones and tendons of a particular patients or, alternatively, for a range of patients of similar size and age. 
     In one example, the fixation system may be positioned further up on the humeral head of the bone, providing significant advantages for angling of the screws that fix the system in place. 
     In one example, a rack and pinion gear mechanism is provided for repositioning one portion relative to another portion. For example, a slider and a ball may be adjustably engaged for positioning by the rack and pinion gear prior to locking the upper portion in relation to the lower portion with a locking mechanism. Alternatively, an anchor may be provided on a lower portion that engages a portion of an upper portion, such as a leaf, such that the upper portion may be joined to soft tissues, such as tendons, ligaments and muscle, using sutures. For example, the anchor portion may comprise a material taking the shape of an anchor, and the upper portion may comprise a slot capable of being engaged and retained by the anchor, without using any separate locking mechanism. In this example, the anchor and slot prevent the upper portion from being pulled free of the anchor, at least until the portion of the upper portion around the slot is bioabsorbed, for example. In one example, various fixation points (which are not necessarily shaped as an anchor, may be disposed within the lower portion and/or the upper portion of the system. For example, a channel and post extending across a thickness of the channel may be provided, the post providing a location for a suture to be anchored. A post may be formed along an edge comprising through holes through the thickness of one section and surface undercuts extending from an edge to the through holes and forming connecting channels permitting a curved suture needle to extend through the channel and hole to pull a suture through the hole while the section remains fixed to a bone by screws or other fixation devices. 
     In one example, a greater tuberosity plate is capable of being secured on the greater tuberosity of the humeral bone and comprises a curved inner surface shaped to anatomically fit a humeral head, for example. In another example, a plate comprises an integrally formed extension on one end, angularly extending transversely to a lower portion. For example, the angle may be anatomically arranged at an angle in a range from 40 to 130 degrees to a remaining portion of the integrally formed fixation device. More preferably, the range is 70 to 110 degrees, even more preferably, 80 to 100 degrees. In one example, the extension is perpendicular to another portion of the plate. In another example, a lower portion comprises a stem having an angle corresponding the shape of a humeral bone and humeral greater tuberosity. Typically, the angle is up to 150 degrees with the average humeral neck shaft angle being about 135 degrees. 
     In another example, a system comprises one or more channels extending into an interior surface. An example is shown of channels in a lower portion of a system, but both the lower and upper portion may have channels. The channels may be used as a way of adjusting the stiffness of portions of the lower and upper portions of the system. For example, a plurality of channels may be formed that intersect at junctions and serve a purpose of adjusting the stiffness of the lower portion, allowing the lower portion to bend in such a way that healing and strength of the bone is improved compared to a strictly rigid lower portion. By allowing some of the stress to be transferred to the bone, channels and bioabsorbable materials may help to provide a more natural callous response during healing. 
     In the claims, anchor refers to an anchor-shaped or T-shaped structural element, the structural element taking on the shape of an anchor for the purpose of engaging with another element, and “anchor” does not mean the broader definition of a point for anchoring a suture. This specific definition of an anchor is provided herein intentionally and disclaims any other interpretation of the term “anchor” within the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following drawings are illustrative examples and do not further limit any claims that may eventually issue. 
         FIG. 1  illustrates a prior art solid fixation device. 
         FIG. 2  illustrates the prior art fixation device fixed on a humeral one for fixing a fracture in the humeral bone. 
         FIG. 3  illustrates an example of an anatomical humeral fixation system as used to repair a humeral fracture. 
         FIG. 4  illustrates another angle of the example of an anatomical humeral fixation system. 
         FIG. 5  illustrates another angle of an example without the humerus. 
         FIG. 6  illustrates a cross section through a portion of an anatomical humeral fixation system. 
         FIG. 7  illustrates an example of a lower portion of the fixation system. 
         FIG. 8  illustrates another example of a lower portion of the fixation system having recessed portions for accommodating tendons, such as the bicep tendon. 
         FIGS. 9A-9C  illustrates another example having ( 9 A) a detachable lesser tuberosity wing and ( 9 B) a detachable greater tuberosity wing. 
         FIGS. 10-10C  illustrate a rack and pinion gear for adjusting the position of the upper portion relative to the lower portion. 
         FIG. 11  illustrates a mechanism for adjusting the angle of the upper portion relative to the lower portion with a plurality of angular degrees of freedom. 
         FIG. 12  illustrates another example an anatomical humeral fixation system as used to repair a humeral fracture and/or tears to humeral tendon and/or muscle tissues. 
         FIG. 13  illustrates an opposite view of the system illustrated in  FIG. 12 . 
         FIG. 14  illustrates a side view of the system illustrated in  FIG. 12 . 
         FIG. 15  illustrates a perspective view of the system illustrated in  FIG. 12 . 
         FIG. 16  illustrates another perspective view of the system illustrated in  FIG. 12 . 
         FIG. 17  illustrates a flexible upper portion capable of being coupled with the system of the system illustrated in  FIG. 12 . 
         FIG. 18  illustrates a flexible upper portion coupled with the system illustrated in  FIG. 12 . 
         FIG. 19  illustrates another example of an anatomical humeral fixation system comprising a rotator cuff plate having a portion extending at a transverse angular direction integrally formed with another portion of the system used for fixing the rotator cuff plate to a bone. 
         FIG. 20  illustrates a side view of the example illustrated in  FIG. 19 . 
         FIG. 21  illustrates an enlarged, perspective view of the example illustrated in  FIG. 1   
         FIG. 22  illustrates yet another example of an anatomical humeral fixation system comprising a greater tuberosity plate. 
         FIG. 23  illustrates a perspective view of the example of  FIG. 22 . 
         FIG. 24  illustrates another example of an anatomical humeral fixation system showing channels formed in an interior surface. 
         FIG. 25  illustrates a partial perspective view of one end of the system showing a depth of a channel and junctions where channels intersect. 
     
    
    
     When the same reference characters are used, these labels refer to similar parts in the examples illustrated in the drawings. 
     DETAILED DESCRIPTION 
       FIG. 1  illustrates a prior art fixation device  1  for a humeral fracture having an optional plate-like pin  2  and screws  4 ,  5 ,  6  and pins  3 , 7  for fixing the fixture onto the humeral bone.  FIG. 2  shows how the fixation device is disposed on the humerus. The device  1  must be disposed on the humeral shaft  10  at a location far from the humeral head  11 , and sutures  8  must be used to connect tendons and the like to the fixture  1 . 
     In contrast, an anatomical fixture system  30  and method disposes an upper portion  31  in contact with the greater tuberosity  12  and lesser tuberosity of the humeral head  11  using wings  33 ,  35 . A plurality of screws  37  with locking threads may be inserted through the upper portion  31  and into the bone below the fixture, as is known in the art. A locking mechanism  39  may comprise a bolt capable of coupling the upper portion  31  to the lower portion  32 . For example, the lower portion  32  may be fixed to the bone using one or more screws  38 , and the upper portion may be adjustably coupled to the lower portion by loosely attaching the upper portion  31  to the lower portion  32  with the locking mechanism  39  loosely fit through a slot  34  in the upper portion. Then, the upper portion may be fixed to the humeral head  11  using screws and/or pins as is known in the art. Subsequently, the head  11  may be repositioned by adjusting the position of the upper portion in relation to the lower portion, and then the locking mechanism  39  may be tightened locking the position of the upper portion in relation to the lower portion of the fixture. 
     In  FIG. 4 , a cut-out  36  is illustrated that avoids a tendon disposed on the humeral bone  10 . In addition, a threaded receptacle  41  and a threaded positioner  42  capable of matingly threading into the receptacle are shown. The positioner  42  is an example of a mechanism for adjusting an angle D of the upper portion  31  in relation to the lower portion  32 .  FIG. 5  illustrates some of the displacement A, B and angles C,D that are adjustable using the locking mechanism  39  and the adjusting mechanism positioner  42  of the system together with the slot  34 . 
       FIG. 6  illustrates a cross section along line B of  FIG. 5 , which together illustrate one example of an adjusting mechanism for adjusting the displacement of the upper portion  31  and the lower portion  32  in an up and down direction A. The locking mechanism  39  in this example is threadingly engaged with a slider  71  that is slidingly engaged in a slot  76 . That extends from a slit  74  through at least an upper surface of an engagement portion  82  of the lower portion  32  of the system  30 . The slit  74  provides an opening  84  on the surface of the engagement portion  82  of the lower portion  32 .  FIG. 8  illustrates a recessed portion  86  for the biceps tendon that fits under the anatomically shaped lower surface of the lower portion  32 , for example. In one example, the system may be fabricated using 3-D printer technology to provide a custom fit to a patient based on 3-D imaging of the patients humeral bone and imaging of tendons. For example, both the fractured humeral bone and the opposite unfractured humeral bone may be imaged to reconstruct how the system will be formed and adjusted to return the fractured pieces of the humeral bone to a location as close as possible to the anatomical location of the pieces prior to injury. Contact surfaces  73 ,  75 ,  79 ,  89  may be prepared in a way that causes these surface to be locked in place once the locking mechanism  39  is tightened, such as by fitting a tool into a correspondingly shaped recess  72  in the locking mechanism  39 . 
     Thus, the system may be anatomically formed to fit the bones and tendons of a particular patients or, alternatively, for a range of patients of similar size and age. One advantage is that the upper portion may be positioned further up on the humeral head of the bone. This provides significant advantages for angling of the screws that fix the system in place, especially when the wings  33 ,  35  are used. In one example, as illustrated in  FIGS. 9A-9C , for example, the wings  33 ,  35  are detachable. For example, pins  93 ,  95  may be used to attach the wings  33 ,  35 , respectively. Alternatively, score lines  91  may be provided that allow the wings to be removed by bending the wings with a removal tool, for example. In one example, the wings may be angularly adjustable in an angular direction F. 
     In one example, repositioning of the upper portion relative to the lower portion may be assisted by an adjusting mechanism as illustrated in the exploded view of  FIGS. 10-10C , for example. A tool  100  may be used to rotate a gear  101  by inserting the tool in a recess in the gear, for example. For example, the gear comprise a pinion capable of engaging a rack for translating the rack in direction B compared to the pinion, which is rotated in direction H, for example.  FIG. 10A  illustrates a partial view of the lower portion and how a rack may be integrated into the engagement portion  82  of the lower portion  32 , for example. The cross section  122  illustrates a recess formed for providing the teeth of the rack, as illustrated. The opening  84  shows the slider  71  and a ball  120  adjustably engaged within the slider  71 . A detailed view of an example of a ball  120  shows a threaded recess  121 , which may be capable of being threadingly engaged with the locking mechanism  39 , for example. 
       FIG. 11  illustrates an example of a slider  71  that is comprised of a ball  120  contained in a recess between two halves  151 ,  152  of the slider  71 . These two halves may be joined together by fasteners  161 ,  163 ,  165 ,  153 ,  154  or may be bonded, welded, brazed, fitted, or otherwise joined one to the other. The slider  71  may have a raised surface  145 , which may be used as a guide and/or locking mechanism, by extending slightly above the surface of the lower portion  32 . The locking mechanism  39  may have a tip  135  capable of orienting the ball  121  for proper threading with the mechanism, for example. The threads  139  may be selected to avoid cross threading and stripping, for example. The underside  137  of the head of the locking mechanism  39  may be provided with a locking surface, such as by providing roughness or surface features capable of locking the underside to a corresponding contact surface. 
     The features illustrated in the drawings may be combined and modified to provide for angular and translational displacement of the upper portion in relation to the lower portion of the system giving many degrees of freedom in repositioning the fractured pieces of bone. For example, a rack and pinion gear may be provided to create compression on a fracture in bone during repositioning of the portions of the system, such as up and down direction A, for example. Alternatively, a set screw  68  or other mechanism may be used to adjust the position of the slider in the slit illustrated in  FIG. 6 . Various combinations of the illustrated features are within the scope of the inventions disclosed. 
       FIGS. 12-18  illustrate another example of an anatomical humeral fixation system as used to repair a humeral fracture and/or tears to humeral tendon and/or muscle tissues. The an anatomical humeral fixation system  200  of  FIG. 12  may be used to repair a humeral fracture and/or tears to humeral tendon and/or muscle tissues. An one-piece, integrated structure is shown comprising a stem  230 , an anchor portion  210 , and eyelet  240  and an arm  220 . In the example, the stem comprises a narrow distal end, a widening mid-portion and a flared head portion. Various holes  234  and slots  232  extend through the thickness of the stem  230 . The anchor portion  210  is formed within an aperture  250  of the flared head portion of the stem  230 . The anchor portion  210  comprises an anchor  212  having an elongated portion  252 . The illustration of  FIG. 12  shows an inner surface  236  that faces a bone  10 , when the system is secured to the bone  10  by screws  4 ,  5 ,  6  or other fixation devices, as known in the art. Various fixation points are located within the stem  230  or the arm  220  extending outwardly from the stem  230 . For example, a channel  224  and post  226  may be utilized as a suture anchor, or a post may be formed along an edge by holes  216  and surface undercuts  214  forming connecting channels permitting a curved suture needle to fit under the head portion, even when the stem  230  is already fixed to a bone  10  using screws  3 ,  4 ,  5 . The arm portion  220  may be made detachable from the stem  230  by providing a score line  222  or other weakness that results in a breakaway arm. 
     The opposite surface  237  of the stem is illustrated in  FIG. 13 . A recessed portion  239  allows an end portion  274  or tongue of a mesh or patch, such as the flexible leaf  270  illustrated in  FIGS. 17 and 18 , even when the stem  230  is fixed to a bone  10  with screws  4 ,  5 ,  6 . In the example in  FIG. 17 , a leaf  270  comprises a hole, slit or slot  276  capable of being fit over the anchor  212  of the anchor portion  210 . The leaf  270  of  FIG. 17  comprises an end portion  274  with a slot  276  and a flared end  272  having holes  278  punched or formed within the flared end  272 .  FIG. 18  illustrates an example of how the leaf  270  is coupled with the anchor portion  210 ,  212  of the stem  230 . The arm portion  210  has a curvature, as best shown in  FIGS. 15 and 16 , such that the arm portion  220  anatomically fits a portion of the humeral bone  10 . Also, the stem  230  has a curvature such that the stem  230  anatomically fits a portion of the humeral bone  10 , as best shown in  FIG. 14 . 
       FIGS. 19-21  illustrate another example of an anatomical humeral fixation system comprising a rotator cuff plate  290  having an angled portion  292  with teeth extending from a lower face of the angled portion  292 , and having screw holes at the vertex, on the stem  294  and on the angled portion  292 . The angled portion  292  extends substantially transversely, at a transverse angular direction, such as a right angle, and is integrally formed with a stem  294 . An outer surface  297  faces away from a bone when fixed on the bone. An inner face  296  has a curved surface anatomically shaped for fitting on and over the top of a humeral head. For example, the plate  290  may be fixed on the humeral head by pulling a torn tendon or other soft tissue over the angled portion  292  and biting the teeth into the greater tuberosity of the humeral head at a soft tissue attachment region. A leaf  270  or other flexible mesh or patch may be attached to the anchor portion  210 ,  212  of the plate  290 , and sutures may be used to couple the flared end  272  to the soft tissue. 
     In one example, the material of the leaf  270  and/or the stem  230  is made of a bioabsorbable material, such as a polylactate or other bioabsorbably prepared polymer. Alternatively, the leaf  270  may be a mesh having an elasticity or visco-elasticity that takes up some or all of the load on the soft tissue, initially, and takes up less stress over time, as the leaf  270  stretches over time, such as by creep or visco-elastic/visco-plastic flow. In another example, the stem is made of a permanent solid, such as by 3-D printing from a polymer, capable of being shaped according to an image of a patients bone, such as a CT-scan or other three dimensional scan of a patient&#39;s skeletal and soft tissue structures. In one example, the stem  230  is formed, cast or machined of a biocompatible metal, such as a steel or titanium alloy. 
     In  FIG. 22 , an anatomical humeral fixation system comprises a greater tuberosity plate  300 , capable of being secured on the greater tuberosity of the humeral bone, for example.  FIG. 23  shows a perspective view illustrating, together with  FIG. 22 , some of the same elements of the system illustrated in  FIGS. 12-21 , and having a curved inner surface shaped to anatomically fit a humeral head, for example. 
     In another example,  FIG. 24  shows a stem  230  comprising channels  410  formed in an interior surface  236  of the stem  230 .  FIG. 25  illustrates an example of a depth and cross junctions of the channels  410 . The channels  410  may have branches  412 ,  414 ,  416 ,  417 ,  418 ,  419  extending from junctions  416 , for example. For example, the channels  410  may be provided to accommodate anatomical features or may be provided to weaken certain portions of the stem  230  to provide greater deformability or flexibility of the stem  230 , such that the stem  230  does not remove all of the stress from a bone. By allowing some of the stress to be transferred to the bone, the channels  410  may help to provide a more natural callous response. If combined with a bioabsorbable material, the channels  410  may provide for an engineered transfer of load from the stem  230  to the bone and soft tissues over time. 
     This detailed description provides examples including features and elements of the claims for the purpose of enabling a person having ordinary skill in the art to make and use the inventions recited in the claims. However, these examples are not intended to limit the scope of the claims, directly. Instead, the examples provide features and elements of the claims that, having been disclosed in these descriptions, claims and drawings, may be altered and combined in ways that are known in the art.