Surgical support for providing knee torsion

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.

BACKGROUND OF THE INVENTION

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.

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.

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

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.

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's inferior/superior axis generally aligned with an axis of the table. The positioning unit has a soleplate for receiving the patient's foot of the leg when the patient'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.

It is thus a feature of at least one embodiment of the invention to support the patient's leg during arthroscopic surgery by stabilizing opposite ends of the knee joint, i.e., above the patient'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.

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.

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's compartments. The varus/valgus stresses on the foot or ankle may be applied independently from the flexion/extension of the foot or ankle.

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.

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's leg according to the dimensions of the leg and to permit varying degrees of flexion and extension of the knee joint.

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.

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.

The soleplate comprises a pivot point including a lock and back plate to provide a forward force on the patient's foot. A calf support may receive the patient's calf of the leg when the foot of the patient is received by the soleplate and restraining the calf against free angulation.

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.

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.

It is thus a feature of at least one embodiment of the invention to provide adequate plantar flexion and dorsi flexion at the patient's ankle.

A foundation may be mounted to the surgical table and provide connectors for selectively and releasably retaining the mounting plate therebetween the connectors.

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.

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's inferior/superior axis is generally aligned with an axis of the table; positioning the patient's foot of the leg when the patient'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.

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's inferior/superior axis generally aligned with an axis of the table. The positioning unit has a foot bridal for receiving the patient's foot of the leg when the patient'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's thigh underneath the knee and cooperating with the foot bridal to provide a tensile force on the leg of the patient.

It is thus a feature of at least one embodiment of the invention to stretch the patient'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.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now toFIG. 1, a knee torsion system10may work in conjunction with a standard surgery table12of the type providing a generally horizontal table top surface14. Proximal and distal mounting plates16aand16bmay be fixed with respect to the table top surface14through underlying base plates17positioned below a surgical drape18to attach directly to the table12as disclosed in the above referenced application.

A rigid rail20may extend between the mounting plates16to attach to the proximal mounting plates16aat a pivot joint22allowing the rail20to pivot with respect to the mounting plates16aabout a vertical axis24normal to the table top surface14. The rigid rail20attaches to the distal mounting plates16bthrough an arcuate track26having a constant radius about axis24and lying generally in a plane parallel to the table top surface14and fixed with respect to the distal mounting plates16b. A lock mechanism28allows the distal end of the rail20to lock at regular detent positions30on the arcuate track26so that the angle at which the rail20pivots about the axis24with respect to the table12may 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.

A slide32may fit on the rail20to slide along the length of the rail20between the pivot joint22and the arcuate track26. The slide32may be locked into any location along the rail20by means of a manual lock element (not shown). A foot stirrup34may be pivotally attached to the top of the slide32at a horizontal pivot37that also allows removal of the foot stirrup34and the locking of the foot stirrup34in an angle about the horizontal pivot37, for example, as described in the above referenced application with respect toFIG. 8. The foot stirrup34may also include a soleplate35supporting a sole of the patient's foot and a calf support39supporting the patient's calf. It will be appreciated that by adjustment of the angle of the rail20and the location of the slide32, a knee36of the patient may be positioned above the axis24at a desired angulation.

Referring now also toFIG. 3, the rail20extends away from the slide32past the pivot joint22to a cantilevered arm portion40that supports an upwardly extending restraint arm42that may be positioned either to the inside or outside of the patient's thigh above the knee36. It will be appreciated that by angulation of the rail20about the axis24, countervailing forces may be applied to a patient's leg above and below the knee36to provide torsion of the desired direction and amount on the knee joint itself.

This knee torsion system10is 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.

Referring now toFIG. 4, in an alternative embodiment, the rail20may be attached to a horizontally extending mounting plate50that may be attached to a foundation52with the latter attached to the table12by a standard table clamping system54. The rail20will extend generally along an axis of the table12from the head to the foot of the table12without rotation as is provided in the first embodiment.

As before, a foot stirrup34may support the foot and leg of a patient56lying face upward on the table surface14. The foot stirrup34attaches to a slide32that may be adjusted along the rail20and thus along the table axis58extending between the foot and head of the table12. As will be discussed in more detail below, the foot stirrup34may also be adjusted in angulation60, such as generally changes the dorsiflexion and plantar flexion of the foot and, separately, the internal or external rotation62of foot.

The rail20may support not only the slide32but also a thigh support mounting plate64that may abut the upper surface of the table12(separated from the table12by a surgical drape) extending laterally from the rail20. The thigh support mounting plate64attaches to the rail20by means of a slide66receiving the rail20allowing the thigh support mounting plate64to be adjustable along axis58with release of a clamp68on the slide66. The clamp68, for example, may operate a threaded element which may tighten against the rail20.

The upper surface of the thigh support mounting plate64provides for a series of vertically oriented and laterally spaced bores70that may receive corresponding downwardly extending pins (not shown) in a lateral thigh support post72. The lateral thigh support post72extends upward from the thigh support mounting plate64and then angles slightly in the superior direction of the patient along axis58to abut one side of the patient's thigh74when the patient's knee is bent and their foot is received within the foot stirrup34. Construction of the lateral thigh support post72is described, for example, in U.S. provisional application 62/256351, filed Nov. 17, 2015, hereby incorporated by reference.

The different bores70permit placement of the lateral thigh support post72at different lateral distances from the rail20to complement its motion along the rail20by means of slide66. Different shapes of lateral thigh support posts including different angulations and heights may be provided to accommodate a wide variety of different surgical requirements.

Referring now toFIGS. 5, 6 and 7, the lower surface of the calf support39of the foot stirrup34may be fixed to an upper swivel coupling76(for example, by weld or machine screws or the like), the upper swivel coupling76allowing swivel rotation62of the foot stirrup34about an axis77. The lower surface of the upper swivel coupling76in turn provides a socket78that may receive a scalloped detent wheel80coaxially therein when the upper swivel coupling76is in a first rotational alignment about axis77with alignment as shown. The key detent wheel80provides a tooth perimeter82interrupted at a front edge by a radially extending key tab84. In the alignment as shown, the key tab84may be received within a corresponding key opening86in the upper swivel coupling76while the scalloped detent wheel80is received in a cylindrical socket communicating with the key opening86.

Rotation of the upper swivel coupling76away from the alignment position, as shown, causes the key tab84to be captured by a retention ridge90in the upper swivel coupling76passing below the tab84and preventing upward removal of the upper swivel coupling76except in the alignment as shown.

As shown best inFIG. 7, a locking knob92may attach to a threaded shaft94received by a corresponding threaded hole in the upper swivel coupling76, the threaded hole passing generally along a radial axis perpendicular to axis77with respect to the keyed detent wheel80. The tip of the threaded shaft94, when the locking knob92is tightened, may be received within a scallop of the scalloped detent wheel80blocking the rotation between the upper swivel coupling76and the detent wheel80when desired.

The detent wheel80may be fixed to a lower swivel coupling98with respect to which the upper swivel coupling76may swivel about axis77.

Extending downward from the lower swivel coupling98at opposed edges along a common lower edge are tabs100which support between them a hinge pin102extending generally longitudinally and perpendicular to the extent of the rail20shown inFIG. 4. This hinge pin102may be received within an upwardly open longitudinal slot104in slider block106. The slider block106may receive the rail20to slide therealong in the manner of slide32. An adjustment knob110may be provided on the side of the slider block106providing a locking screw (not shown) that may serve to lock the sliding block106in a particular location along the rail20.

Referring also toFIGS. 8 and 9, one vertical wall of the slot104in the upper surface of the slider block106may be removed in part to receive an end124of a quick release handle120. The opposite end of the quick release handle120extends generally along the axis58where it may be easily manipulated by the user. The quick release handle120is mounted to pivot about a laterally extending pivot pin122extending through sidewalls of the block106and through an end of the pivot handle120.

The end124roughly approximates the missing wall of the slot104and may be moved by moving pivot handle120to permit receipt of the hinge pin102and capture of the hinge pin102in the slot104until released by movement of the handle120.

In this regard, as shown inFIG. 8, when handle120is elevated, the end124becomes substantially vertical and continuous with the walls of the slot104to permit reception of the hinge pin102in the slot104. As shown inFIG. 9, when the handle120is dropped, a lower portion126of the end124of the handle120projects into the slot104to prevent the hinge pin102from escaping. Upward motion of the hinge pin102strikes this lower portion126further locking it against the proper direction of rotation needed to release the hinge pin102.

It will be appreciated that the motion of the foot stirrup34in angulation60is provided by rotation of the hinge pin102in the slot104while swiveling of rotation62is provided by rotation of the upper swivel coupling76with respect to the lower swivel coupling98. Extension of the foot along the rail20is provided by sliding of the block106.

Referring now toFIGS. 4 and 10, the foundation52may be separated from the mounting plate50, the latter attached to the rail20, by a sterile drape18. In this regard, the foundation52may provide horizontally opposed retention hooks130aand130bthat may be separated slightly to admit the mounting plate50therebetween, and then the retention hooks130aand130bclosed together to firmly grip the mounting plate50through the sterile drape18.

The retention hook130bmay be mounted on a first plate portion132battached to the foundation52fixedly and thus fixed with respect to the table12. A guide bar134may extend horizontally from plate132a, plate132aholding hook130a, to be received in a corresponding channel136in the plate132b. Engagement of the guide bar134and channel136allows the plates132aand132bto move freely toward and away from each other.

Plate132aalso includes spring bars138and139attached to and extending from the plate132aparallel to and on either side of guide bar134beneath the plate130. These spring bars138and139attached to a plate stop141. When the plates132aand132bare positioned together, firmly holding the mounting plate50in the hooks130aand130b, the plate stop141extends beyond the leftmost edge of plate132band is biased upward by the spring bars138and139to engage the left outer surface of plate132bpreventing separation of the plates132aand132bto firmly hold the mounting plate50. The plates132aand132bmay be separated by pressing downward on the plate stop141with flexure of the spring bars138and139, allowing the plate stop141to pass beneath the plate132bwith separation of the plates132aand132bto release the mounting plate50.

Referring now toFIGS. 12 and 13, the present invention including the rail20, the mounting plate50, and the slide32may also be used for other procedures such as ankle arthroscopy in which a flexible foot bridal140attached to the patient's foot may be connected in tension by cord142to the slide32, the cord142tensioned by tension adjuster144. In this case, the lateral thigh support post72may be replaced with a leg support post150extending upward from the table surface14and having a knee support arm152extending laterally over the surface14of the table12to support the lower portion of the patient's thigh74beneath the knee. An upper distal end of the leg support post150may include sockets154for holding surgical tools and the lower proximal end of the leg support post150may have downwardly extending pins156to be received within bores70of the thigh support mounting plate64shown inFIG. 1.

Referring now toFIGS. 4 and 14, a tension strap160may be attached between the lower side of the soleplate35of the foot stirrup34and a second slide162similar to slide32but positioned on the inferior end of rail20. The lower end of the tension strap160may provide for a stirrup162having a crossbar164fitting within the slot of the slide162similar to slot104of slide32and retained therein by corresponding handle120. A turnbuckle adjustment166joins the stirrup162with a clevis joint168that may releasably attached to a loop (not shown) on the bottom of the soleplate35. By tensioning the turnbuckle166, upward pressure from the calf support39may be applied to the patient's lower leg effected through a pivot point of hinge pin similar to hinge pin102shown inFIG. 5.