Abstract:
The present invention provides a fixture that may be releasably attached to the operating table to apply two countervailing forces to the leg on opposite sides of the knee. These forces permit the application of a precise and stable torque to the knee joint. In one embodiment, the fixture may be repositioned and fixed with respect to the operating table through the surgical drape without penetration of the surgical drape.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of U.S. provisional application 62/136,810 filed Mar. 23, 2015 and US provisional application 62/300,436 filed Feb. 26, 2016, both of which are hereby incorporated in their entireties by reference. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    — 
       BACKGROUND OF THE INVENTION 
       [0003]    The present invention relates to a surgical support system for supporting a patient during surgery and in particular to a support system that can be attached to and adjusted with respect to the operating table to provide torsion to the knee joint. 
         [0004]    During knee surgeries and procedures it is often necessary to apply torsional forces to the knee in order to open or stress the lateral or medial sides of the joint. For example, during arthroscopic surgeries, controlled manipulation of the joint is necessary to allow viewing by an arthroscope and access to the compartments of the knee for repair. When the knee is extended, the lateral and medial gutters may be exposed. When the knee is flexed, the notch and groove of the femur may be exposed. When varus medial and valgus lateral stresses are applied to the knee, the meniscus may be exposed. The type and degree of stress placed on the knee varies during the course of surgery. 
         [0005]    As standard practice, these forces are applied manually by grasping the foot or ankle and pushing or pulling the foot or ankle in a direction perpendicular to the normal extent of the leg and with the knee held fixed by a post by a hand placed aside the knee. This process is inconsistent, unstable, and usually requires a second person to apply the force. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention provides a fixture that may be releasably attached to the operating table to apply two countervailing forces to the leg on opposite sides of the knee. These forces permit the application of a precise and stable torque to the knee joint. In one embodiment, the fixture may be repositioned and fixed with respect to the operating table through the surgical drape without penetration of the surgical drape using the techniques described in co-pending application Ser. No. 14/255,131 filed Apr. 17, 2014, and hereby incorporated by reference.  
         [0007]    Specifically, the invention provides a surgical leg positioning unit for positioning a leg of a human patient with the patient lying supine on an upper surface of a surgical table and the patient&#39;s inferior/superior axis generally aligned with an axis of the table. The positioning unit has a soleplate for receiving the patient&#39;s foot of the leg when the patient&#39;s knee of the leg is bent and extending upward from the table and restraining the foot against free angulation; a resistive post positioned to abut a lateral side of a thigh of the leg of the patient and cooperating with the soleplate to provide a lateral torsion on the thigh of the patient; and a support frame adjustably receiving and retaining the soleplate and the resistive post to control a longitudinal separation between the soleplate and the resistive post along the axis of the table controlling a bending of the knee and a lateral displacement of the resistive post across the axis of the table controlling a torsion on the knee. 
         [0008]    It is thus a feature of at least one embodiment of the invention to support the patient&#39;s leg during arthroscopic surgery by stabilizing opposite ends of the knee joint, i.e., above the patient&#39;s knee and at the foot or ankle, in order to apply a precise and stable torque to the knee joint without extraneous movement of the leg. 
         [0009]    A first swivel joint permits the soleplate to rotate horizontally about a second axis perpendicular to the upper surface of the surgical table. A first pivot joint permits rotation of the soleplate at an angle with respect to the table about a third axis parallel to the upper surface of the surgical table. A second swivel joint permits the rail to rotate horizontally about a fourth axis perpendicular to the upper surface of the tabletop. 
         [0010]    It is thus a feature of at least one embodiment of the invention to twist the foot or ankle to apply varus/valgus stresses in varying degrees of flexion/extension to permit examination of the knee&#39;s compartments. The varus/valgus stresses on the foot or ankle may be applied independently from the flexion/extension of the foot or ankle. 
         [0011]    The support frame has a rail extending along a length of the upper surface of the surgical table and a slide constrained against rotation along the second and third axes coupled to the soleplate and engaging the rail to permit sliding of the soleplate horizontally along the rail. A slide constrained against rotation along the second and third axes is coupled to the resistive post and engages the rail to permit sliding of the resistive post horizontally along the rail. Relative positions of the soleplate and resistive post may be independently adjustable along the rail.  
         [0012]    It is thus a feature of at least one embodiment of the invention to allow repositioning of the soleplate and/or the resistive post along the patient&#39;s leg according to the dimensions of the leg and to permit varying degrees of flexion and extension of the knee joint. 
         [0013]    A post mounting plate may adjustably receive and retain the resistive post to control a position of the resistive post along a fifth axis normal to the rail. The post mounting plate may provide a plurality of laterally spaced bores selectively receiving correspondingly shaped pins of the resistive post at laterally spaced locations from the rail. A cross section of the bores and correspondingly shaped pins may be vesica piscis shaped. 
         [0014]    It is thus a feature of at least one embodiment of the invention to allow removable and selective adjustment of the resistive post outward along a transverse plane of the body for varying degrees of abduction of the leg. The post mounting plate may allow insertion of a variety of different resistive posts (e.g., different sizes and shapes) for a variety of purposes. 
         [0015]    The soleplate comprises a pivot point including a lock and back plate to provide a forward force on the patient&#39;s foot. A calf support may receive the patient&#39;s calf of the leg when the foot of the patient is received by the soleplate and restraining the calf against free angulation. 
         [0016]    It is thus a feature of at least one embodiment of the invention to prevent further flexion of the knee by supporting the foot at a fixed angle of flexion/extension. 
         [0017]    A strap may be attached at a lower side of the soleplate on a first end and the rail at an opposite second end and control a tensive force on the patient foot in a downward direction. 
         [0018]    It is thus a feature of at least one embodiment of the invention to provide adequate plantar flexion and dorsi flexion at the patient&#39;s ankle. 
         [0019]    A foundation may be mounted to the surgical table and provide connectors for selectively and releasably retaining the mounting plate therebetween the connectors. 
         [0020]    It is thus a feature of at least one embodiment of the invention to allow the mounting plate to be removeably installed to the surgical table so that a sterile sheet may be positioned between the mounting plate and the table without penetration, thus providing a sterile shield. 
         [0021]    The invention also provides a method of positioning a leg of a human patient after surgery with the patient lying supine on an upper surface of a surgical table, comprising the steps of: positioning the patient on the upper surface of the surgical table so that the patient&#39;s inferior/superior axis is generally aligned with an axis of the table; positioning the patient&#39;s foot  of the leg when the patient&#39;s knee of the leg is bent and extending upward from the table into a soleplate restraining the foot against free angulation; bending a knee of the patient so that a lateral side of a thigh of the leg of the patient abuts a resistive post cooperating with the soleplate to provide a lateral torsion on the thigh of the patient; and adjusting a longitudinal separation between the soleplate and the resistive post along a support frame adjustably receiving and retaining the soleplate and resistive post along an axis of the table controlling a bending of the knee and a lateral displacement of the resistive post across the axis of the table controlling a torsion on the knee. 
         [0022]    In an alternative embodiment, the invention provides a surgical leg positioning unit for positioning a leg of a human patient with the patient lying supine on an upper surface of a surgical table and the patient&#39;s inferior/superior axis generally aligned with an axis of the table. The positioning unit has a foot bridal for receiving the patient&#39;s foot of the leg when the patient&#39;s knee of the leg is bent and extending upward from the table and tensioned away from an attachment point of the leg; a cord attached between the foot bridal and the upper surface of the surgical table providing a downward tensile force on the foot bridal; and a resistive post extending laterally over the upper surface of the surgical table and positioned to abut the lower portion of the patient&#39;s thigh underneath the knee and cooperating with the foot bridal to provide a tensile force on the leg of the patient. 
         [0023]    It is thus a feature of at least one embodiment of the invention to stretch the patient&#39;s leg in a direction of the normal extent of the leg in order to open up the ankle joint during ankle arthroscopy for improved visualization. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0024]      FIG. 1  is a perspective view of a first embodiment of the fixture of the present invention as attached to a surgical table through a surgical drape prior to positioning of the patient; 
           [0025]      FIG. 2  is a figure similar to that of  FIG. 1  showing the patient&#39;s leg position on the fixture; 
           [0026]      FIG. 3  is a side elevational and top plan view of the fixture showing the patient leg in phantom as positioned on the fixture;  
           [0027]      FIG. 4  is a perspective view in fragment of a second embodiment of the fixture of the present invention; 
           [0028]      FIG. 5  is an exploded diagram of a foot stirrup of the second embodiment having a mounting providing angulation and rotation of the ankle and lower leg; 
           [0029]      FIG. 6  is a fragmentary partial cross-section of the rotation mechanism of the mounting of  FIG. 5 ; 
           [0030]      FIG. 7  is a top view of the rotation mechanism of  FIG. 6  in partial cutaway; 
           [0031]      FIGS. 8 and 9  are vertical cross-sections through a mounting showing the steps of release and engagement of the foot stirrup; 
           [0032]      FIG. 10  is a side elevational view of a table mount for receiving the present invention through a sterile field defined by a polymer sheet; 
           [0033]      FIG. 11  is a top plan view in partial fragment of the table mount showing a mechanism for allowing snap engagement of the mount to the fixture; 
           [0034]      FIG. 12  is a perspective elevational view of the fixture of the present invention used for ankle arthroscopy; 
           [0035]      FIG. 13  is a perspective view of the lake support used in the ankle arthroscopic system of  FIG. 12 ; and 
           [0036]      FIG. 14  is a view of a stabilizer harness used on the foot support of  FIG. 4 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Embodiment 1 
       [0037]    Referring now to  FIG. 1 , a knee torsion system  10  may work in conjunction with a standard surgery table  12  of the type providing a generally horizontal table top surface  14 . Proximal and distal mounting plates  16   a  and  16   b  may be fixed with respect to the table top surface  14  through underlying base plates  17  positioned below a surgical drape  18  to attach directly to the table  12  as disclosed in the above referenced application. 
         [0038]    A rigid rail  20  may extend between the mounting plates  16  to attach to the proximal mounting plates  16   a  at a pivot joint  22  allowing the rail  20  to pivot with respect to the mounting plates  16   a  about a vertical axis  24  normal to the table top surface  14 . The rigid rail  20  attaches to the distal mounting plates  16   b  through an arcuate track  26  having a constant radius about axis  24  and lying generally in a plane parallel to the table top surface  14  and fixed with respect to the  distal mounting plates  16   b . A lock mechanism  28  allows the distal end of the rail  20  to lock at regular detent positions  30  on the arcuate track  26  so that the angle at which the rail  20  pivots about the axis  24  with respect to the table  12  may be changed. The angular range of rotation will typically be 20 degrees and may be, for example, 30 degrees. The lock mechanism may automatically lock at any detent position and may be manually unlocked to allow for further rotation. 
         [0039]    A slide  32  may fit on the rail  20  to slide along the length of the rail  20  between the pivot joint  22  and the arcuate track  26 . The slide  32  may be locked into any location along the rail  20  by means of a manual lock element (not shown). A foot stirrup  34  may be pivotally attached to the top of the slide  32  at a horizontal pivot  37  that also allows removal of the foot stirrup  34  and the locking of the foot stirrup  34  in an angle about the horizontal pivot  37 , for example, as described in the above referenced application with respect to  FIG. 8 . The foot stirrup  34  may also include a soleplate  35  supporting a sole of the patient&#39;s foot and a calf support  39  supporting the patient&#39;s calf. It will be appreciated that by adjustment of the angle of the rail  20  and the location of the slide  32 , a knee  36  of the patient may be positioned above the axis  24  at a desired angulation. 
         [0040]    Referring now also to  FIG. 3 , the rail  20  extends away from the slide  32  past the pivot joint  22  to a cantilevered arm portion  40  that supports an upwardly extending restraint arm  42  that may be positioned either to the inside or outside of the patient&#39;s thigh above the knee  36 . It will be appreciated that by angulation of the rail  20  about the axis  24 , countervailing forces may be applied to a patient&#39;s leg above and below the knee  36  to provide torsion of the desired direction and amount on the knee joint itself. 
         [0041]    This knee torsion system  10  is superior to the current practice in four ways. 1. It does not require a second person to apply the torsional force. 2. Due to the leverage of the rail, the force is easily applied with one hand. 3. The force stays in place until purposefully relieved via the interlocking portions of the main rail and arcuate track. This leaves the surgeon with both hands available to perform the procedure. 4. The fixed position of the rail eliminates movement of the patient caused by a third person applying force manually.  
       Embodiment 2 
       [0042]    Referring now to  FIG. 4 , in an alternative embodiment, the rail  20  may be attached to a horizontally extending mounting plate  50  that may be attached to a foundation  52  with the latter attached to the table  12  by a standard table clamping system  54 . The rail  20  will extend generally along an axis of the table  12  from the head to the foot of the table  12  without rotation as is provided in the first embodiment. 
         [0043]    As before, a foot stirrup  34  may support the foot and leg of a patient  56  lying face upward on the table surface  14 . The foot stirrup  34  attaches to a slide  32  that may be adjusted along the rail  20  and thus along the table axis  58  extending between the foot and head of the table  12 . As will be discussed in more detail below, the foot stirrup  34  may also be adjusted in angulation  60 , such as generally changes the dorsiflexion and plantar flexion of the foot and, separately, the internal or external rotation  62  of foot. 
         [0044]    The rail  20  may support not only the slide  32  but also a thigh support mounting plate  64  that may abut the upper surface of the table  12  (separated from the table  12  by a surgical drape) extending laterally from the rail  20 . The thigh support mounting plate  64  attaches to the rail  20  by means of a slide  66  receiving the rail  20  allowing the thigh support mounting plate  64  to be adjustable along axis  58  with release of a clamp  68  on the slide  66 . The clamp  68 , for example, may operate a threaded element which may tighten against the rail  20 . 
         [0045]    The upper surface of the thigh support mounting plate  64  provides for a series of vertically oriented and laterally spaced bores  70  that may receive corresponding downwardly extending pins (not shown) in a lateral thigh support post  72 . The lateral thigh support post  72  extends upward from the thigh support mounting plate  64  and then angles slightly in the superior direction of the patient along axis  58  to abut one side of the patient&#39;s thigh  74  when the patient&#39;s knee is bent and their foot is received within the foot stirrup  34 . Construction of the lateral thigh support post  72  is described, for example, in U.S. provisional application 62/256351, under docket 3127.001, filed Nov. 17, 2015, hereby incorporated by reference. 
         [0046]    The different bores  70  permit placement of the lateral thigh support post  72  at different lateral distances from the rail  20  to complement its motion along the rail  20  by means of slide  66 . Different shapes of lateral thigh support posts including different angulations and heights may be provided to accommodate a wide variety of different surgical requirements.  
         [0047]    Referring now to  FIGS. 5, 6 and 7 , the lower surface of the calf support  39  of the foot stirrup  34  may be fixed to an upper swivel coupling  76  (for example, by weld or machine screws or the like), the upper swivel coupling  76  allowing swivel rotation  62  of the foot stirrup  34  about an axis  77 . The lower surface of the upper swivel coupling  76  in turn provides a socket  78  that may receive a scalloped detent wheel  80  coaxially therein when the upper swivel coupling  76  is in a first rotational alignment about axis  77  with alignment as shown. The key detent wheel  80  provides a tooth perimeter  82  interrupted at a front edge by a radially extending key tab  84 . In the alignment as shown, the key tab  84  may be received within a corresponding key opening  86  in the upper swivel coupling  76  while the scalloped detent wheel  80  is received in a cylindrical socket communicating with the key opening  86 . 
         [0048]    Rotation of the upper swivel coupling  76  away from the alignment position, as shown, causes the key tab  84  to be captured by a retention ridge  90  in the upper swivel coupling  76  passing below the tab  84  and preventing upward removal of the upper swivel coupling  76  except in the alignment as shown. 
         [0049]    As shown best in  FIG. 7 , a locking knob  92  may attach to a threaded shaft  94  received by a corresponding threaded hole in the upper swivel coupling  76 , the threaded hole passing generally along a radial axis perpendicular to axis  77  with respect to the keyed detent wheel  80 . The tip of the threaded shaft  94 , when the locking knob  92  is tightened, may be received within a scallop of the scalloped detent wheel  80  blocking the rotation between the upper swivel coupling  76  and the detent wheel  80  when desired. 
         [0050]    The detent wheel  80  may be fixed to a lower swivel coupling  98  with respect to which the upper swivel coupling  76  may swivel about axis  77 . 
         [0051]    Extending downward from the lower swivel coupling  98  at opposed edges along a common lower edge are tabs  100  which support between them a hinge pin  102  extending generally longitudinally and perpendicular to the extent of the rail  20  shown in  FIG. 4 . This hinge pin  102  may be received within an upwardly open longitudinal slot  104  in slider block  106 . The slider block  106  may receive the rail  20  to slide therealong in the manner of slide  32 . An adjustment knob  110  may be provided on the side of the slider block  106  providing a locking screw (not shown) that may serve to lock the sliding block  106  in a particular location along the rail  20 .  
         [0052]    Referring also to  FIGS. 8 and 9 , one vertical wall of the slot  104  in the upper surface of the slider block  106  may be removed in part to receive an end  124  of a quick release handle  120 . The opposite end of the quick release handle  120  extends generally along the axis  58  where it may be easily manipulated by the user. The quick release handle  120  is mounted to pivot about a laterally extending pivot pin  122  extending through sidewalls of the block  106  and through an end of the pivot handle  120 . 
         [0053]    The end  124  roughly approximates the missing wall of the slot  104  and may be moved by moving pivot handle  120  to permit receipt of the hinge pin  102  and capture of the hinge pin  102  in the slot  104  until released by movement of the handle  120 . 
         [0054]    In this regard, as shown in  FIG. 8 , when handle  120  is elevated, the end  124  becomes substantially vertical and continuous with the walls of the slot  104  to permit reception of the hinge pin  102  in the slot  104 . As shown in  FIG. 9 , when the handle  120  is dropped, a lower portion  126  of the end  124  of the handle  120  projects into the slot  104  to prevent the hinge pin  102  from escaping. Upward motion of the hinge pin  102  strikes this lower portion  126  further locking it against the proper direction of rotation needed to release the hinge pin  102 . 
         [0055]    It will be appreciated that the motion of the foot stirrup  34  in angulation  60  is provided by rotation of the hinge pin  102  in the slot  104  while swiveling of rotation  62  is provided by rotation of the upper swivel coupling  76  with respect to the lower swivel coupling  98 . Extension of the foot along the rail  20  is provided by sliding of the block  106 . 
         [0056]    Referring now to  FIGS. 4 and 10 , the foundation  52  may be separated from the mounting plate  50 , the latter attached to the rail  20 , by a sterile drape  18 . In this regard, the foundation  52  may provide horizontally opposed retention hooks  130   a  and  130   b  that may be separated slightly to admit the mounting plate  50  therebetween, and then the retention hooks  130   a  and  130   b  closed together to firmly grip the mounting plate  50  through the sterile drape  18 . 
         [0057]    The retention hook  130   b  may be mounted on a first plate portion  132   b  attached to the foundation  52  fixedly and thus fixed with respect to the table  12 . A guide bar  134  may extend horizontally from plate  132   a , plate  132   a  holding hook  130   a , to be received in a corresponding channel  136  in the plate  132   b . Engagement of the guide bar  134  and channel  136  allows the plates  132   a  and  132   b  to move freely toward and away from each other.  
         [0058]    Plate  132   a  also includes spring bars  138  and  139  attached to and extending from the plate  132   a  parallel to and on either side of guide bar  134  beneath the plate  130 . These spring bars  138  and  139  attached to a plate stop  141 . When the plates  132   a  and  132   b  are positioned together, firmly holding the mounting plate  50  in the hooks  130   a  and  130   b , the plate stop  141  extends beyond the leftmost edge of plate  132   b  and is biased upward by the spring bars  138  and  139  to engage the left outer surface of plate  132   b  preventing separation of the plates  132   a  and  132   b  to firmly hold the mounting plate  50 . The plates  132   a  and  132   b  may be separated by pressing downward on the plate stop  141  with flexure of the spring bars  138  and  139 , allowing the plate stop  141  to pass beneath the plate  132   b  with separation of the plates  132   a  and  132   b  to release the mounting plate  50 . 
         [0059]    Referring now to  FIGS. 12 and 13 , the present invention including the rail  20 , the mounting plate  50 , and the slide  32  may also be used for other procedures such as ankle arthroscopy in which a flexible foot bridal  140  attached to the patient&#39;s foot may be connected in tension by cord  142  to the slide  32 , the cord  142  tensioned by tension adjuster  144 . In this case, the lateral thigh support post  72  may be replaced with a leg support post  150  extending upward from the table surface  14  and having a knee support arm  152  extending laterally over the surface  14  of the table  12  to support the lower portion of the patient&#39;s thigh  74  beneath the knee. An upper distal end of the leg support post  150  may include sockets  154  for holding surgical tools and the lower proximal end of the leg support post  150  may have downwardly extending pins  156  to be received within bores  70  of the thigh support mounting plate  64  shown in  FIG. 1 . 
         [0060]    Referring now to  FIGS. 4 and 14 , a tension strap  160  may be attached between the lower side of the soleplate  35  of the foot stirrup  34  and a second slide  162  similar to slide  32  but positioned on the inferior end of rail  20 . The lower end of the tension strap  160  may provide for a stirrup  162  having a crossbar  164  fitting within the slot of the slide  162  similar to slot  104  of slide  32  and retained therein by corresponding handle  120 . A turnbuckle adjustment  166  joins the stirrup  162  with a clevis joint  168  that may releasably attached to a loop (not shown) on the bottom of the soleplate  35 . By tensioning the turnbuckle  166 , upward pressure from the calf support  39  may be applied to the patient&#39;s lower leg effected through a pivot point of hinge pin similar to hinge pin  102  shown in  FIG. 5 .  
         [0061]    Certain terminology is used herein for purposes of reference only, and thus is not intended to be limiting. For example, terms such as “upper”, “lower”, “above”, and “below” refer to directions in the drawings to which reference is made. Terms such as “front”, “back”, “rear”, “bottom” and “side”, describe the orientation of portions of the component within a consistent but arbitrary frame of reference which is made clear by reference to the text and the associated drawings describing the component under discussion. Such terminology may include the words specifically mentioned above, derivatives thereof, and words of similar import. Similarly, the terms “first”, “second” and other such numerical terms referring to structures do not imply a sequence or order unless clearly indicated by the context. 
         [0062]    When introducing elements or features of the present disclosure and the exemplary embodiments, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of such elements or features. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements or features other than those specifically noted. It is further to be understood that the method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed. 
         [0063]    It is specifically intended that the present invention not be limited to the embodiments and illustrations contained herein and the claims should be understood to include modified forms of those embodiments including portions of the embodiments and combinations of elements of different embodiments as come within the scope of the following claims. All of the publications described herein, including patents and non-patent publications, are hereby incorporated herein by reference in their entireties.