Ankle holder for maintaining an ankle and a foot of a patient during a surgical intervention

Abstract

The present invention concerns an ankle holder (200, 200') for maintaining an ankle (A) and a foot (F) of a patient (P) on an operating table, the ankle holder (200, 200') comprisinga base plate (210) configured to be secured to the operating table (140); a holder (220, 220') configured to maintain the ankle (A) and the foot (F) while a surgical zone comprising a malleolar region of the foot remains accessible for surgery, the holder (220, 220') comprising; a body part (221, 221') in connection with the base plate (210) along a longitudinal axis (X), and a supporting part (222, 222') configured to support the foot (F) and the ankle (A) of the patient (P), wherein the supporting part (222, 222') and the body part (221, 221') of the holder (220, 220') are linked to one another by a pivoting arrangement (223, 223'), the holder (220, 220') being configured to adjust the ankle (A) between a plantar flexion position and a dorsiflexion position, by a rotation of the supporting part (222, 222') around a pivoting axis (T) of the pivoting arrangement (223, 223').

Description

ANKLE HOLDER FOR MAINTAINING AN ANKLE AND A FOOT OF A PATIENT DURING A SURGICAL INTERVENTIONFIELD OF INVENTION

[0001] The present invention pertains to the general domain of orthopedic surgeries, more precisely to ankle and foot surgeries, and especially to systems permitting to maintain a member, or part of a member in a determined position to enable surgery, more precisely during a robotized surgery.BACKGROUND OF INVENTION

[0002] The ankle joint can be affected by several diseases, with clinical presentation varying from mild pain or swelling to inability, becoming in some cases a serious problem in daily life activities. Ankle surgery is required to treat pathologic conditions such as arthritis, deformity, fracture, impingement, tendonitis, osteophytes, instability, and tendon tears. Even though low invasive procedures using arthroscopy remains possible in some cases, open surgeries remain the most traditional procedure due to ankle joint anatomical specificities, like small space and tangential view that make arthroscopy more difficult.

[0003] The ankle joint replacements, also known as ankle arthroplasties or total ankle replacement, is a surgery which has been traditionally reserved for patients older 50 years old and with low physical demand, and which involves implanting an implant to help a patient recover full motility of his / her ankle. Such implant comprises at least three distinct parts: a talar component, a tibial component and an insert positioned between the talar component and the tibial component and which allows movements of both components with respect to each other and with respect to said insert. To implement those parts, the bones are prepared beforehand. Especially, cuts are realized on the tibia and on the talus to permit fixation of the different components. Obviously, the precision of those cuts is directly related to the correct positioning of the different components of the implant and, consequently, to the level of motility recovered after the surgery. The word “cut” here is employed largely to designate any kind of machining of the concerned bone.

[0004] Currently, ankle arthroplasty is widespread increasing, and indications are expanding thanks to a steady improvement in prosthetic designs, and the development ofseveral different techniques. However, there is an increasing need to open this surgery to a wider range of patient age, with higher physical demand. In such conditions, known techniques, mostly relying on manual techniques and strongly dependent on surgeons’ know-how, are not satisfying. There is a need to standardize surgical procedure, increase precision in order to provide better outcomes for the patient and reduce short-term and long-term complications.

[0005] Thus, surgeons are now starting to contemplate the option of robotized ankle arthroplasties. Using a robot to assist the surgeon permits improvement of the reliability and accuracy of the cut performed on the bones. Even though this kind of surgery is realized with the aid of optical tracking system, as for instance described in the document US2020 / 0129311, it is still desirable to prevent excessive displacements of the ankle joints during the surgery, and to hold a required position in order to reduce the risk of error when the cuts are realized. It may also be desirable to enable adjustment in the angular position of ankle joint according to surgeon needs.

[0006] These drawbacks are already known relating to knee arthroplasties. Those surgeries have been robotized for several years now and leg-holders particularly adapted to be used to maintain the operated leg of the patients have been developed. Unfortunately, those leg-holders are not adapted to be used for ankle arthroplasties. Most of them allow to choose an angle of the knee and to lock the knee according to the chosen angle, but the position of the ankle cannot be modified. Moreover, those leg-holders are often shaped as boots, thus restraining considerably the accessibility of the ankle for the surgeon. This drawback is limitative during robotized surgeries as the workspace of a robot - meaning the zone accessible by the robot - is often quite restricted. Boots shaped leg holder cannot provide a satisfying solution for ankle surgery as the malleolar and midfoot zone are covered, thus inaccessible for surgeries.

[0007] The present invention aims at solving at least the cited drawbacks by proposing an ankle-holder particularly adapted to be used during ankle surgeries, more precisely during robotized ankle surgery.SUMMARY

[0008] An object of the present invention thus concerns an ankle holder to maintain an ankle and a foot of a patient on an operating table, the ankle holder comprising a base plate configured to be secured to the operating table, a holder configured to maintain the ankle and the foot while a surgical zone comprising a malleolar region of the foot remains accessible for surgery, the holder comprising a body part in connection with the base plate along a longitudinal axis , and a supporting part configured to support the foot and the ankle of the patient, wherein the supporting part and the body part of the holder are linked to one another by a pivoting arrangement, the holder being configured to adjust the ankle between a plantar flexion position and a dorsiflexion position, by a rotation of the supporting part around a pivoting axis of the pivoting arrangement.

[0009] In other words, the ankle older of the invention enables to maintain the foot of the patient during surgery, while surgeons can adjust the position of the device in order to modify the degree of flexion of the ankle from a plantar flexion position to a dorsiflexion position.

[0010] The plantar flexion position describes the extension of the ankle so that the foot points down and away from the leg, while the dorsiflexion position is the flexion of the ankle opposite to plantar flexion position, thus the ankle bends backwards, in order to have the toes pointing toward the shin.

[0011] This allows surgeon to adjust the ankle position in order to perform different surgical steps. The inventions also enable a wide access to the surgical zone, meaning that none of the part of the device are obstructing or creating blindspot around the surgical zone, which comprises the malleolar region.

[0012] The invention can be complemented by one or several of the following features, alone or in combination.

[0013] The ankle holder presents a general L-shape, comprising a first branch comprising a proximal area and a distal area, the first branch extending along a position axis, and a second branch extending along a heel axis orthogonal to the position axis, the position axis and the heel axis joint together at a junction point and the junction point is part of the proximal area.

[0014] In other words, the foot of the patient is placed on the holder in order to be supported by the L-shape ankle holder. The first branch supports the plantar of the foot while the second branch is supporting the back of the heel. This enables the foot to be properly adjusted on the holder and avoids the foot to slide down during surgery.

[0015] The proximal area comprises an aperture configured to receive a heel of the foot. The aperture enables to stabilize the position of the foot on the ankle holder. More advantageously the aperture enables the ankle holder to be compatible with multiple foot sizes as a larger heel can protrude through the opening, without penalizing the support of the ankle by the second branch.

[0016] The second branch is configured to provide a complementary shape that is complementary to a shape of the ankle, the complementary shape is configured to support the ankle when the position of the ankle is adjusted, between a plantar flexion position and a dorsiflexion position

[0017] In other words, the second branch as a shape configured to support the back side of the lower leg, more precisely the back part of the ankle, even more precisely comprising the back part of the heel defined by the shape of the posterior part of the calcaneus being circular and the Achille tendon creating an inward curvature. A branch presenting a complementary shape to the back side of the ankle enables to support the ankle from plantar flexion to dorsiflexion without provoking any blockage of the ankle, nor any unwanted displacement of the general position of the foot. A longitudinal displacement resulting from the ankle position adjustment would be compensated by a knee position adjustment or by a thigh position adjustment, while the ankle is properly maintained.

[0018] The complementary shape has a convex profile, comprising a first portion extending from the junction point, orthogonally to the first branch, and a second portion extending tangentially from the first portion, and bending outwardly from the first branch with a radius comprised between 130 and 270mm, preferably between 170 mm and 220 mm.

[0019] In other words the complementary shape may have two portions, the first portion being configured to support the heel while the second portion being configured to support to the calcaneus tendon, also called Achille tendon. A complementary shape providing at least two portions provide greater support and continuous contact from the heel to thecalcaneous tendon when the position of the ankle is adjusted from a dorsiflexion position to a plantar flexion position. The support provided by the complementary shape is thus continuous and avoid any blockage of the ankle.

[0020] The second branch has a branch height, measured along the heel axis and from the junction point, that is inferior to 13 cm, preferably inferior to 11 cm. In other words, the second branch as a contacting surface along the heel axis inferior to 13 cm. This allows to support the heel up to the Achille tendon without provoking any blockage of the ankle due to the shape of the calf when the ankle is adjusted between a dorsiflexion position to a plantarflexion position.

[0021] The first branch comprises a plantar contacting surface configured to support the foot, and wherein the plantar contacting surface is configured to provide a top access angle to the surgical zone greater than or equal to 90° around the positioning axis and between lateral edges of the plantar contacting surface. In other word, the plantar contacting surface describes an angle greater than or equal to 90° around the positioning axis, from a first lateral edge to a second lateral edge.

[0022] The second branch comprises a heel contacting surface configured to support the foot, notably a back side of the foot. The heel contacting surface is configured to provide a front access to the surgical zone greater than or equal to 90° when measured around the heel axis and between outer edges of the heel contacting surface. In other words, the heel contacting surface describes an angle greater than or equal to 90° around the heel axis, from a first outer edge to a second outer edge. The plantar contacting surface and the heel contacting surface being the only sources of blind spot on the ankle, having the greater top access angle and front access angle maximizes the accessible surgical zone

[0023] The pivoting axis intersects with the pivoting arrangement and is perpendicular to the longitudinal axis. In other words, the pivoting axis is transverse to the pivoting arrangement and perpendicular to the longitudinal axis in order to bend the ankle from a dorsiflexion position to a plantar flexion position.

[0024] The pivoting axis and the longitudinal axis together define a plane parallel to the base plate.

[0025] The pivoting axis passes through the ankle and is perpendicular to the longitudinal axis. In other words, the pivoting axis is transverse to the ankle, following the natural movement of the ankle and perpendicular to the longitudinal axis in order tobend the ankle from a dorsiflexion position to a plantar flexion position. This advantageously enables to move the ankle without stretching the leg during surgery when ankle position adjustment is needed.

[0026] The body part is mobile along a longitudinal axis (X) with respect to the base plate. A body part being displaceable along a base plate enables to adapt the position of the ankle holder according to the length of patient leg and to the position of the patient on the operating table. Advantageously, a body part that is mobile avoids multiple repositioning of the device.

[0027] The base plate comprises a rail extending along the longitudinal axis and wherein the body part of the holder comprises a longitudinal notch configured to engage the rail. Thus, the rail and the longitudinal notch form a runner.

[0028] The holder comprises a locking device configured to lock the position of the body part with respect to the base plate.

[0029] The pivoting arrangement comprises a locking apparatus configured to lock a position of the supporting part with respect to the body part of the holder. Advantageously, the locking apparatus is designed to permit to adjust the position of the holder within a range of position and to lock the supporting part in a required position for surgery with respect to the body part.

[0030] The supporting part comprises a neck configured to receive a strap enabling to hold the foot on the supporting part. Advantageously the neck prevents the strap to slide and improves foot placement on the supporting part. Advantageously the neck is positioned on the distal part of the first branch in order to apply the strap on the foot, more precisely on the forefoot.

[0031] The pivoting axis is at a distance from the base plate configured to avoid electromagnetic perturbation of the electromagnetic field emitted by electromagnetic transmitter. In other words, the pivoting axis is above the base plate at a distance avoiding electromagnetic perturbation of the electromagnetic field emitted by the electromagnetic transmitter in any position of the ankle holder.

[0032] The ankle holder comprises at least one electromagnetic transmitter configured to emit at least one electromagnetic field. Advantageously the electromagnetic transmitter enables the ankle older to be used in robotized surgery using electromagnetic trackers for surgery.

[0033] The electromagnetic transmitter is attached to a flexible element removably secured to the holder. The flexible element is deformable between at least two stable positions. Advantageously, the transmitter follows the movement of the supporting plate.

[0034] The ankle holder, comprises at least one electromagnetic transmitter configured to emit at least one electromagnetic field, and the electromagnetic transmitter is attached to a flexible element removably secured to the holder the flexible element being deformable between at least two stable positions. Advantageously the tracker is removable, enabling proper cleaning of the device without damaging the transmitter.

[0035] The flexible element is configured to be secured to the holder according to, at least, two different attaching sites. In other words, the flexible element can be secured to the holder according to, at least, two different attaching sites. Advantageously the two different attaching sites are formed on opposed positions of the ankle holder, thus ensuring that the transmitter can always be positioned medially with respect to the treated ankle. This enables the device to be used either for left ankle or a right ankle.

[0036] The flexible element is secured to the body part of the holder.

[0037] The ankle holder comprises at least five radio-opaque elements arranged according to a predetermined pattern.

[0038] The radio-opaque elements are embedded in the holder. Advantageously, the radio-opaque elements are embedded within the supporting part of the holder to be as close as possible to the ankle and the foot. Alternatively, the radio-opaque elements could be embedded within the body part of the holder. Alternatively, the radio-opaque elements could be attached, for instance glued to the holder or pressed into such holder.

[0039] The radio-opaque elements are shaped as beads in order to improves position tracking

[0040] The ankle holder comprises an attachment configured to receive a surgical instrument. This attachment is formed on the holder of the ankle holder. For instance, the surgical instrument is a probe comprising a localization sensor. The localization sensor is an electromagnetic receiver configured to receive and measure the electromagnetic field emitted by the electromagnetic transmitter.

[0041] The ankle holder is mainly made of a radiolucent material. Obviously, the radioopaque elements are not made of the radiolucent material.BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 is a general view of a computer-assisted surgery system adapted to be used to perform an ankle arthroplasty on a patient’ s leg;

[0043] Figure 2A and Figure 2B are, respectively, a medial perspective view and a lateral perspective view of an ankle holder according to a first embodiment of the invention, the ankle holder being illustrated with a schematic leg;

[0044] Figure 3 is a general view an ankle illustrating movements from a plantar flexion position to a dorsiflexion position.

[0045] Figures 4 and Figure 5 are, respectively, a medial perspective view and a lateral perspective view of an ankle holder according to a first embodiment of the invention, the ankle holder being illustrated with a schematic leg;

[0046] Figure 6 is the lateral perspective view of the ankle holder according to the first embodiment illustrated without the leg;

[0047] Figure 7 is a rear view of the ankle holder according to the first embodiment;

[0048] Figures 8A to 8C illustrate three different positions of the ankle holder according to the first embodiment of the invention; Figure 8A illustrate the ankle holder in dorsiflexion position, Figure 8B illustrate the ankle holder in an intermediate position, more particularly in a standing position; Figure 8C illustrate the ankle holder in a plantar flexion position.

[0049] Figures 9A and 9B are cross-section views of part of the ankle holder illustrating a pivoting arrangement according to the first embodiment;

[0050] Figure 10 is a schematic and partial section view of the ankle holder according to the first embodiment, illustrating a top surgical angle defining the accessible surgical zone.

[0051] Figures 11A and 11B are cross-section views of part of a body part of the ankle holder according to the first embodiment illustrated in cooperation with a base plate of the ankle holder;

[0052] Figure 12 is a perspective lateral view of the ankle holder according to an alternative first embodiment, illustrated without the leg;

[0053] Figures 13A to 13D are views of the pivoting arrangement according to the alternative first embodiment of the invention, figures 13B and 13D being enlargements of part of figures 13A and 13C.

[0054] Figures 14 is a perspective lateral view of the ankle holder according to a second embodiment;

[0055] Figure 15A and Figure 15B are cross sectional view of the ankle holder of the second embodiment in an intermediate position on figure 15A and on a platar flexion position on figure 15B

[0056] Further details and advantages are described hereunder in relation to the accompanying drawing.DETAILED DESCRIPTION

[0057] Referring to figure 1, a computer -assisted surgery system 100 is illustrated. Such system 100 is particularly adapted to perform an ankle arthroplasty on a patient P lying on an operating table 140 and it comprises a cart 101 from which extends a robotic arm 102 with motorized joints and which is holding a surgical tool 110, the robotic arm 102 being adapted to allow displacements of the surgical tool 110 according to at least six degrees of freedom. The operating table 140 can be equipped with securing means 141, such as clamps commonly used to secure different objects. Advantageously, the robotic arm 102 can further be adapted to permit displacements of the surgical tool 110 along at least one redundant degree of freedom, i.e., a total of at least seven degrees of freedom. The surgical tool 110 is, advantageously, removably held by the robotic arm 102 and it can be changed. For instance, the computer-assisted surgery system 100 can comprise at least one input device - not shown - and at least one processing unit adapted to receive inputs transmitted by the user through the input device and to compute instructions to be sent to motorized joints of the robotic arm so as to displace the surgical tool as commanded by the user, but with safety parameter - not detailed in this document - considered by said processing unit. For instance, the input device can be formed as a joystick or a handle mounted on the robotic arm, near the surgical tool 110. Optionally, the system can comprise a display, illustrated here as mounted on the cart 101.

[0058] The processing unit can, for instance, comprise one or more microprocessors, one or more random access memories (RAM) and / or one or more read-only memories (ROM), one or more calculators, one or more computers and / or one or more computer programs. The computer program(s) comprise code instructions to compute the needed instructions to be sent to the motorized joints of the robotic arm. In addition, theprocessing unit may include other devices and circuitry for performing the functions described herein such as, for example, a hard drive, input / output circuitry, and the like. The input / output circuitry can be adapted to treat digital and / or analog signals.

[0059] The computer-assisted surgery system 100 can be used with an ankle holder 200, schematically represented on figure 1. This ankle holder 200 is designed to maintain the ankle of the patient in a defined position and will be described with more details below.

[0060] The computer-assisted surgery system 100 can be associated with an electromagnetic tracking system. Such an electromagnetic tracking system is for instance partially illustrated on figure 2 and comprises at least two transducers, one of the transducers - also referred to as a transmitter 230 - being configured to emit an electromagnetic field and the other one of the transducers - also referred to as a receiver- to respond to the emitted magnetic field. In a particular arrangement, the electromagnetic tracking system comprises one electromagnetic transmitter arranged near the ankle to be treated, and several receivers respectively implanted in the bones of the concerned ankle. As known by the person of the art, electromagnetic tracking systems are particularly sensitive to the presence of disturbing material, such as metallic tools for instance. One way to avoid the disturbances generated by those disturbing materials is to locate the transmitter as close as possible to the receivers. As represented on figure 2, the ankle holder 200 of the invention is equipped with one electromagnetic transmitter 230, thus permitting to keep the electromagnetic transmitter in close vicinity with the receivers- not shown here - which are to be implanted in the ankle’s bones.

[0061] As illustrated from figures 4 to 15B the ankle holder 200 comprises a base plate 210 extending, mainly, along a longitudinal axis X adapted to be secured to the operating table 140. The ankle holder 200 comprises a holder 220, 220’ that is made of at least two parts articulated with respect to one another and configured to maintain the ankle A and the foot F while a surgical zone comprising a malleolar region of the foot remains accessible for surgery. As illustrated on figures 2A and figure 2B, the malleolar region MAR of the foot F comprises each of the two bony projections of the leg, one on the outside and the other on the inside, which make up the ankle. It corresponds to the end part of the fibula and the end parts of the tibia. The malleolar region MAR also comprises the talus bone. The surgical zone may comprise other foot regions such as the midfoot region MFR. The ankle holder enables to hold the ankle while limiting contacting surfaceswith the foot in order to maximize the surface of interest for surgery, meaning that no parts of the ankle holder are in contact or obstructing or creating blind spots which could hinder the access for surgery.

[0062] The holder 220 comprises a body part 221 and a supporting part 222. The body part 221 may be mobile with respect to the base plate 210 along the longitudinal axis X, as schematically illustrated with the arrow A on figure 2. The supporting part 222 is configured to support the ankle A and the foot F of the patient. The supporting part 222 is linked to the body part 221 by a pivoting arrangement 223 so that the supporting part 222 is mobile with respect to the body part 221 around a positioning axis T perpendicular to the longitudinal axis X. The pivoting arrangement 223 enables the holder 220 to adjust the ankle between a plantar flexion position and a dorsiflexion position, by a rotation of the supporting part 222 around the pivoting axis T of the pivoting arrangement 223.

[0063] According to the illustrated example, the body part 221 is mounted on a rail 211 attached to the base plate 210. According to the illustrated embodiment, the rail 211 and the base plate 210 are made of a single piece. Thus, the rail and the base plate cannot be separated from one another without damaging at least one of the rails 211 or the base plate. The body part 221 comprises a longitudinal notch 224 configured to engage the rail 211. The rail 211 and the longitudinal notch 224 together form a runner. The holder 220 comprises a locking device 260, only partially visible on figure 3, configured to lock a position of the body part 221 with respect to the base plate 210. This locking device 260 will be detailed below with reference to figures 11 A and 1 IB.

[0064] Alternatively, the base plate 210 may be a repositionable adhesive in connection with the body part 221. The base plate 210 may be an auto gripping layer positioned under the body part 221 and configured to secured the ankle holder 200 on the operating table 140. Advantageously, this configuration adapts to any surfaces. More advantageously, this configuration provides a lighter and more compact ankle holder than the precited embodiment. This configuration will be illustrated along the second embodiment of the invention illustrated from figures 14 to 15B.

[0065] As illustrated on figure 3, a plantar flexion position describes the extension of the ankle so that the foot points down and away from the leg, while a dorsiflexion position is the flexion of the ankle opposite to plantar flexion position, thus the ankle bends backwards, in order to have the toes pointing toward the shin. A maximal dorsiflexionposition is obtained by bending the foot backward from a standing position from 20° to 30°. A maximal plantar flexion position is obtained by extending the foot from a standing position from 40° to 50°. The standing position corresponds to a 90° angle formed between the foot F and the leg. In other words, the standing position corresponds to a 90° position angle formed between the positioning axis Y and the longitudinal axis X. The supporting part 222 can be displaced with respect to the body part 221 around the positioning axis T so that the supporting part 222 forms a minimal angle of 40° measured between the longitudinal axis X and the positioning axis Y in an extremal plantar flexion position as disclosed in figure 4. The supporting part 222 can be displaced with respect to the body part 221 around the positioning axis T so that the supporting part 222 form an maximal position angle of 120° measured between the longitudinal axis X and the positioning axis Y in an extremal dorsiflexion position. Advantageously, the supporting part 222 can be adjusted according to multiple intermediate positions within a range of 90° at maximum, more preferably within a range or 80°at maximum. Advantageously, the supporting part 222 can be adjusted according to multiple intermediate positions within a range of 30° at minimum, more preferably within a range or 40° at minimum even more preferably within a range of 50° at minimum. Those multiple positions allow the surgeon to position the ankle of the patient according to a chosen angle facilitating the intervention. The pivoting arrangement 223 thus permits to adjust the foot F and the ankle A of the patient so that the bones or soft tissues to be treated can be easily accessible for the surgeon.

[0066] Figures 4 to 6 are lateral perspective views of the ankle holder 200 illustrated with the leg on figure 4 and figure 5 and without the leg on figure 6, thus making visible the supporting part 222 of the holder 220. Figure 7 provides a rear view of the ankle holder 200. As shown, the supporting part 222 has a general L-shape comprising two branches: a first branch also referenced as the upper branch 222a and the second branch also referenced as the lower branch 222b. The first branch 222a comprises a proximal area 2221a and a distal area 2222a. The first branch 222a extends along a position axis Y, and intends to be in contact with the foot from a plantar contacting surface 223. The second branch 222b extends along a heel axis Z orthogonal to the position axis Y and intends to be in contact with the heel H with a heel contacting surface 224. The positionaxis Y and the heel axis Z join together at a junction point J and the junction point J is part of the proximal area 2221a.

[0067] The proximal area 2221a may comprises an aperture 222c configured to receive a heel of the foot F. The aperture 222c is formed at the junction of said branches 222a, 222b so as to receive part of a heel H of the patient. Especially, the lower branch 222b is thus adapted to support part of the heel, while the upper branch 222a is adapted to support the foot F. The aperture 222c is advantageously shaped to prevent unwanted displacements of the heel and to limit unwanted displacements of the foot.

[0068] As illustrated on figures 9A and figure 9B, the second branch 222b may have a complementary shape that is complementary to the ankle A and configured to support the ankle A when the ankle A is adjusted from a plantar flexion position and a dorsiflexion position. The complementary shape is adapted to the heel H anatomy and provides an adapted support according the position of the ankle holder. Advantageously, the second branch 222b has a convex profile comprising a first portion Pl extending from the junction point J, orthogonally to the first branch 222a, and a second portion P2 extending tangentially from the first portion Pl, and bending outwardly, away from the first branch 222a, with a radius comprised between 130 and 270mm, preferably between 170 mm and 220 mm. Those two portions enable to adapt the support provided to the ankle. The portion Pl provides a greater support in a position from neutral to extremal dorsiflexion. The portion P2 provides a greater support in a position from neutral to extremal plantar flexion.

[0069] The second the branch 222b has a branch height 222bh, measured along the heel axis Z from the junction point J, that is inferior to 13 cm, preferably inferior to 11 cm in order to provide support to the ankle A from the heel H to the lower part of the Achille tendon. Outer edges may protrude outwardly around the leg to provide lateral support. The second branch 222b is in contact with the foot from a heel contacting surface 302.

[0070] As illustrated on figure 10, an access to the surgical zone is provided by limiting the plantar contacting 300 surface of the first branch 222a. Alternatively, the access to the surgical zone is provided by limiting the heel contacting surface 302 of the second branch 222b. A greater access to the surgical zone may be provided by limiting both the plantar contacting surface 300 of the first branch 222a and the heel contacting surface 302 of the second branch 222b.

[0071] The branches may comprise external edges configured to laterally maintain the foot F. The first branch 222a may protrude in the direction of the foot F, covering medial and lateral side of the foot F. The plantar contacting surface 300 may be flat and the lateral edges protruding in direction of the foot describes a top surgical angle 304 greater than or equal to 90° measured around the positioning axis Y and from a first lateral edge 3011 to a second lateral edge 30 Ir. Advantageously the top surgical angle 304 is greater than 100°, more advantageously greater than 110°, even more advantageously greater than 120°. The top surgical angle is preferably greater than 150°. A first lateral edge 3011 being on the lateral side and the second lateral edge 30 Ir being on the medial side of the foot. At maximum, the plantar contacting surface 300 describes a top surgical angle of 180°, so that the supporting part 222 is flat from the first lateral edge 3011 to the second lateral edge 30 Ir, advantageously on the proximal part 2221a of the first branch 222a of the supporting part 222.

[0072] For the same reasons, the second branch 222b may protrude in the direction of the foot F, covering medial and lateral side of the foot. The heel contacting surface 302 describes a front surgical angle 305 greater than or equal to 90° measured around the heel axis Z and from a first outer edge 303 to a second outer edge 303. Advantageously the front surgical angle in greater than 100°, more advantageously greater than 110°, even more advantageously greater than 120°. The front surgical angle is preferably greater than 150°. A first outer edge being on the lateral side and the second outer edge being on the medial side of the foot. At maximum, the heel contacting surface describes a front surgical angle of 180°, so that the supporting part is flat from the first outer edge to the second outer edge.

[0073] The ankle holder 200 also comprises straps - not shown here - used to prevent unwanted displacements of the foot and thus to maintain said foot in position. The symmetric shape of the supporting part 222 of the holder 220 also advantageously permits to use the ankle holder to perform arthroplasty on left ankles as well as on right ankles. The supporting part 222 may comprises a forefoot fixation system 400. As illustrated on figure 7 the forefoot fixation system 400 may be a neck configured to receive a strap enabling to hold the foot F on the supporting part 222, advantageously positioned on the distal part 2222a of the supporting part 222a. Alternatively, the forefoot fixation system 400 comprises a latch as disclosed on figure 15 and 15B configured to receive a strap.Alternatively, the forefoot fixation system 400 is a slipper-like shape configured to receive the forefoot of a patient foot F.

[0074] As illustrated on figure 14 to 15B, the ankle holder 200 may comprises a handle 500, advantageously positioned on the supporting part 222, more preferably positioned on the distal part of the supporting part 222.

[0075] As illustrated on figure 4 to 15B the ankle holder 200 is further equipped with an electromagnetic transmitter 230 configured to emit at least one electromagnetic field. This electromagnetic transmitter 230 is also part of the electromagnetic tracking system evoked above. This electromagnetic transmitter 230 is mounted on a flexible element 225 attached to the holder 220. The flexible element 225 is deformable between at least two stable positions. Advantageously, the flexible element 225 is deformable between several stable positions. Using such a flexible element ensures to be able to position the electromagnetic transmitter 230 as close as possible to the ankle to be treated, and thus to the electromagnetic receivers which are to be implanted in the concerned bones. Obviously, the ankle holder 200 is made of a material compatible with the use of an electromagnetic tracking system, that is to say, a material which does not disturb the electromagnetic field emitted by the electromagnetic transmitter, or cause minimal or unisignificant distorsion of the electromagnetic field. Advantageously, such material is also radiolucent as detailed below.

[0076] The electromagnetic transmitter is at distance from the based plate to avoid electromagnetic perturbation of the electromagnetic field due to the proximity of the ankle holder with the operating table. Thus the ankle holder 200 is configured so that a minimal distance separates the pivoting axis T from the base plate, in order to avoid electromagnetic perturbation of the electromagnetic field emitted by electromagnetic transmitter 230 in any possible positions. Advantageously the distance between the electromagnetic transmitter 230 and the base plate 210 is at least of 8 cm in any position of the supporting plate, from the extremal plantar flexion position and the extremal dorsiflexion position, and is generally comprised between 8cm and 15 cm.

[0077] Especially, the flexible element 225 is mounted on the body part 221 of the holder 220. Advantageously, the body part 221 comprises two attaching sites 226 configured to receive the flexible element 225. Advantageously, these attaching sites 226 allow to use the ankle holder 200 for performing surgeries on left and right ankles while alwaysensuring that the electromagnetic transmitter 230 is positioned medially with respect to the ankle to be treated.

[0078] The ankle holder 200 of the invention further comprises a pattern of radio-opaque elements 240. Especially, the ankle holder 200 comprises at least five radio-opaque elements 240 arranged according to a known pattern. According to the illustrated embodiment, these radio-opaque elements 240 are embedded in the ankle holder 200 and particularly in the holder. These embodiments are also made visible on figures 9A and 9B. In order to be as close as possible to the ankle to be treated, the radio-opaque elements 240 are advantageously embedded in the supporting part of the holder. Alternatively, the radio-opaque elements 240 could be attached, for instance glued to the holder, or pressed into such holder. These radio-opaque elements 240 can for instance be used to generate a 3D model of the ankle to be treated directly in the operating room. Per-operative images can be acquired in the operating room to obtain images of the ankle A to be treated. The radio-opaque elements 240 are advantageously used to compile the obtained images and, thus, to compute the 3D model of the ankle A. These radio-opaque elements 240 can for instance be formed as beads made of a radio-opaque material, as the per-operative images are often acquired using fluoroscopic imaging. To ensure the recognition of these radioopaque elements, the rest of the ankle holder 200 is advantageously made of a radiolucent material.

[0079] As can be particularly seen on figure 7, the ankle holder 200, and particularly its supporting part 222, comprises an attachment 227 here represented as receiving a probe 111 equipped with an electromagnetic receiver 231. Obviously, this attachment 227 could be used to attach any other kind of surgical instrument which could be useful during the surgery. Furthermore, this attachment could alternatively be attached to the displacing part 221 of the holder 220 within the scope of the invention. Figure 7 also makes visible part of a locking apparatus 250 which is part of the pivoting arrangement and configured to lock and unlock the position of the supporting part 222 with respect to the body part 221, as detailed below.

[0080] As illustrated on figures 4 to 12, a first embodiment of the invention describes an ankle holder 200 wherein the supporting part 222 is linked to the body part 221 by a pivoting arrangement 223 so that the supporting part 222 is mobile with respect to the body part 221 around a pivoting axis T perpendicular to the longitudinal axis X. Asshown, the longitudinal axis X and the pivoting axis T together define a plane Pl parallel to the base plate 210. As shown on figures 4 to 12, the pivoting axis T intersects with the pivoting arrangement 223, 223’. Preferably the pivoting axis T is perpendicular to the longitudinal axis X. The first embodiment describes with a body part 221 mobile along the longitudinal axis X in regards to the base plate. However, this feature shall not be seen as a limitative example.

[0081] As illustrated on figures 8 A to 8C, the supporting part 222 can be displaced with respect to the body part 221 around the pivoting axis T and can be locked in two extreme positions being previously defined the extremal plantar flexion position and the extremal dorsiflexion position illustrated on figures 8C and 8A and at least one intermediate position illustrated on figure 8B. Advantageously, the supporting part 222 can be locked in position with respect to the body part 221 according to multiple intermediate positions so as to allow the surgeon to position the ankle of the patient according to a chosen angle facilitating the intervention. The pivoting arrangement 223 thus permits to position the foot F and the ankle A of the patient so that the bones to be treated can be easily accessible for the surgeon. The ankle holder 200 of the invention generally has an open shape permitting easy access to the ankle A of the patient. According to the invention, the supporting part 222 is rotatable with respect to the body part 221 only around the pivoting axis T.

[0082] According to figures 9A and 9B which illustrate cross-section views of part of the holder 220 according, respectively, to a locked position and an unlocked position, the locking apparatus 250 comprises lever 251 configured to engage with a toothed wheel 252 to lock the position. Especially, the lever 251 pivots around an axis T’ parallel to the pivoting axis T evoked above and the toothed wheel 252 is equipped with teeth on a quarter of its perimeter. The lever 251 is further urged to the locked position by an elastic element 253, thus ensuring that the unlocked position is only used voluntarily by the surgeon and / or their assistant. Part of the lever 251 extends on the rear side of the supporting part 222 so as to be accessible for the surgeon or his / her assistant. Using a toothed wheel 252 also permits to define authorized locking positions. Forming the teeth only on part of the perimeter of the wheel further permits to define a maximal angle at which the ankle can be bend. For instance, the supporting part 222 can be displaced from-30° to +50° with respect to a vertical position wherein said supporting part 222 is perpendicular to the base plate 210.

[0083] Figures 11A and 11B are cross-section views of part of the ankle holder 200 illustrating, respectively, a locked position and an unlocked position of the locking device 260 used to lock the position of the body part 221 with respect to the base plate 210. As more visible on figure 2 to 4, the rail 211 of the base plate 210 according to the first embodiment comprises indentations 212 orientated downward, i.e., toward the base plate 210. The locking device 260 comprises a push button 261, that is to say a button 262 associated with an elastic means 263, such as a spring, configured to urge the button 262 upward, i.e., away from the base plate. As illustrated, an abutting element 264 configured to engage with the indentations 212 of the rail 211 is attached to the button 262, on its lower extremity 265. According to the illustrated example, the abutting element 264 is screwed to the lower extremity 265 of the button 262, but obviously the abutting element 264 could be attached to the button by any other known means without departing from the scope of the invention. For instance, the two pieces could be made of a single piece, or the abutting element could be glued on the button within the scope of the invention. Thus, when the push button 261 is urged upward by its elastic means 263, the abutting element 264 is engaged with one of the indentations 212 of the rail 211, thus locking the position of the body part 221 with respect to the base plate 210. If the user of the ankle holder needs to displace the supported ankle, he / she must press on an upper extremity 266 of the push button 262, downward, to disengage the abutting element 264 from the concerned indentation 212. The user can then displace the body part 221 to the desired position and then release the push button 262 so that the abutting element 264 can engage with another indentation 212 of the rail 211.

[0084] Figures 12 to 13B illustrate an alternative of the first embodiment of the ankle holder 200’ for which only the differences are going to be described.

[0085] Figure 12 is a perspective view of the ankle holder 200’ wherein the locking device 260’ is configured to lock the position of the body part 221’ with respect to the base plate 210 and regarding the pivoting arrangement 223’, and especially the locking apparatus 250’ of this pivoting arrangement, used to lock the position of the supporting part 222’ with respect to the body part 221’ . The general shape of the supporting part 222’is also different from the supporting part 222 of the first embodiment, in that the lower branch 222’b is wider than the lower branch of the first embodiment.

[0086] The rail 211’ of the base plate 210 according to an alternative of the first embodiment also differs from the rail of the first embodiment in the orientation of the indentations 212’ which are orientated transversally with respect to the rail 211’. These indentations 212’ are part of the locking device 260’. As shown, the locking device 260’ comprises a push button 261’ arranged on a first side of the body part 210’ while, according to the first embodiment, the equivalent push button was arranged on a top of the body part 221. The internal mechanism is identical to the mechanism described with reference to the first embodiment illustrated on figures 10A and 10B.

[0087] The alternative of the first embodiment also differs from the first embodiment in the design of the pivoting arrangement 223’, and particularly in the design of the locking apparatus 250’ of such pivoting arrangement 223’. As can be seen on figure 12, the lever of the locking apparatus is replaced by a depressible button 251’ arranged on a first side of the supporting part 222’. Figures 13A to 13D illustrate the locking apparatus 250’ according to the alternative ot the first embodiment, figures 13A and 13B illustrating a locked position while figures 13C and 13D illustrate an unlocked position. Figures 13B and 13D are enlarged views of the circled parts represented on, respectively, figure 13A and figure 13C. The depressible button 251’ comprises a button 252’ urged to the locked position illustrated on figure 13A by an elastic element 253’, i.e, towards a first end 254’. A first toothed ring 256’ is attached to a second end 255’ of the button 252’, this first toothed ring 256’ being configured to engaged with a corresponding second toothed ring 257’ attached to the supporting part 222’. The first toothed ring 256’ is further equipped with at least one pin 258’ which connects, in rotation, said first toothed ring 256’ to the supporting part 222. Thus, when the first toothed ring 256’ is rotated, the supporting part 222 rotates with it around the pivoting axis T. A shared advantage of the pivoting arrangement 223, 223’ according to the first embodiment and the alternative of the first embodiment, as well shared by the locking device 260, 260’ according to the first embodiment and the alternative of the first embodiment is that they are easy to use, even when the ankle holder is covered by a sterile drape as might be the case in an operating room.

[0088] As illustrated on figures 14 to 15B, a second embodiment of the invention describes an ankle holder 200 wherein the supporting part 222 is linked to the body part 221 by a pivoting arrangement 223 so that the supporting part 222 is mobile with respect to the body part 221 around a pivoting axis T perpendicular to the longitudinal axis X. The longitudinal axis X and the pivoting axis T together define a plane Pl secant to the base plate 210.

[0089] As shown on figures 15A and 15B, the pivoting axis T passes through the ankle A and is perpendicular to the longitudinal axis X. In other words, the pivoting axis is transverse to the ankle, allowing to follow the natural movement of the ankle and perpendicular to the longitudinal axis in order to bend the ankle from a dorsiflexion position to a plantar flexion position.

[0090] The ankle A has a rotation center. Ideally, the pivoting axis T passes through the ankle A rotation center, being at a distance comprised between 6cm and 15cm .from the base plate. Given the difference in morphology from one patient to another, the distance between the rotation centre of the ankle A and the pivoting axis T, when measured in a plane defined by the longitudinal axis X and the heel axis Z, may vary, but the ankle holder 200 is configured so that the distance is less than 50mm, and even more preferably less than 30mm.

[0091] As previously illustrated on figures 14 to 15B, the supporting part 222 can be displaced with respect to the body part 221 around the pivoting axis T and can be locked in two extreme positions previously defined by the extremal plantar flexion position illustrated on figure 15B and the extremal dorsiflexion position and at least one intermediate position illustrated on figure 15 A. Advantageously, the supporting part 222 can be locked in position with respect to the body part 221 according to multiple intermediate positions so as to allow the surgeon to position the ankle A of the patient according to a chosen angle facilitating the intervention. By limiting the distance between the pivoting axis T and the ankle A rotation center, the second embodiment enables to reduces the stretching of the patient leg and reduces forces applied by the surgeon on the ankle holder 200 when the ankle position is adjusted.

[0092] The ankle holder 200 of the second embodiment comprises a locking apparatus 250 with comprises lever 251 configured to engage with a toothed wheel 252 to lock the position. The toothed wheel of figure 15A and 15B is positioned under the supportingplate, comprising a region under the supporting plate opposite to the contacting surface, comprising the second branch and the first branch. The toothed wheel of figure 15A and 15B is positioned under the heel and behind the heel of the foot of the patient. The toothed wheel comprises a groove engaged in the pivoting arrangement 253 and configured to enables a rotation of the supporting plate around a pivoting axis T passing through the ankle rotation center.

[0093] Especially, the lever 251 is triggered in order to release the toothed wheel and enable the lever 251 pivots around the pivoting axis T. The lever 251 can be triggered by pressure. The lever 251 can be triggered by rotation, the lever 251 can be triggered by pulling. The lever 251 may be triggered by a combination of different precited actions to prevent from undesired release of the device.

[0094] The lever 251 is further urged to the locked position by an elastic element 253, thus ensuring that the unlocked position is only voluntarily used by the surgeon and / or their assistants. The elastic element 253 may be a compression spring or an elastic part. The lever 251 extends on the rear side of the supporting part 222 so as to be accessible for the surgeon or his / her assistant. Using a toothed wheel 252 also permits to define authorized locking positions. Forming the teeth only on part of the perimeter of the wheel further permits to define a maximal angle at which the ankle can be bended. For instance, the supporting part 222 can be displaced from -30° to +50° with respect to a vertical position wherein said supporting part 222 is perpendicular to the base plate 210. The lever 251 may be motorized for an automatic control from an external device or a controller.

[0095] The base plate 210 of the second embodiment has been illustrated as a repositionable adhesive in connection with the body part 221. Alternatively, the body part 221 can be mobile along a the longitudinal axis X with respect to the base plate as illustrated with the first embodiment.

[0096] Obviously, the elements described as “first” or “second” embodiment could be combined within the scope of the invention. For instance, an ankle holder of the invention could comprise the locking device according to the first embodiment, while the pivoting arrangement, and thus the corresponding locking apparatus could be realized according to the second embodiment without departing from the scope of the invention.

Claims

CLAIMS1. Ankle holder (200, 200’) to maintain an ankle (A) and a foot (F) of a patient (P) on an operating table (140), the ankle holder (200, 200’) comprising a base plate (210) configured to be secured to the operating table ( 140) ; a holder (220, 220’) configured to maintain the ankle (A) and the foot (F) while a surgical zone comprising a malleolar region of the foot remains accessible for surgery, the holder (220, 220’) comprising a body part (221, 221’) in connection with the base plate (210) along a longitudinal axis (X), and a supporting part (222, 222’) configured to support the foot (F) and the ankle (A) of the patient (P), wherein the supporting part (222, 222’ ) and the body part (221 , 221’ ) of the holder (220, 220’) are linked to one another by a pivoting arrangement (223, 223’), the holder (220, 220’) being configured to adjust the ankle (A) between a plantar flexion position and a dorsiflexion position, by a rotation of the supporting part (222, 222’) around a pivoting axis (T) of the pivoting arrangement (223, 223’).

2. Ankle holder (200, 200’) according claim 1, wherein the holder (220, 220’) presents a general L-shape, comprising a first branch (222a) comprising a proximal area (2221a) and a distal area (2222a), the first branch (222a) extending along a position axis Y, and a second branch (222b) extending along a heel axis (Z) orthogonal to the position axis (Y), the position axis (Y) and the heel axis (Z) joint together at a junction point (J) and the junction point (J) is part of the proximal area (2221a).

3. Ankle holder (200, 200’) according to claim 2, wherein the proximal area (2221a) comprises an aperture (222c) configured to receive a heel of the foot (F).

4. Ankle holder (200, 200’) according to claim 2 or 3, wherein second the branch (222b) is configured to provide a complementary shape (2221b) that is complementary to a shape of the ankle (A), the complementary shape (2221b) is configured to support the ankle (A) when the position of the ankle (A) is adjusted, between a plantar flexion position and a dorsiflexion position.

5. Ankle holder (200, 200’) according to claim 4, wherein the complementary shape (2221b) has a convex profile comprising:a first portion (Pl) extending from the junction point (J), orthogonally to the first branch (222a), and a second portion (P2) extending tangentially from the first portion (Pl), and bending outwardly from the first branch (222a) with a radius comprised between 130 mm and 270 mm, preferably between 170 mm and 220 mm.

6. Ankle holder (200, 200’) according to claim 4 or 5, wherein the second branch (222b) has a branch height, measured along the heel axis (Z) and from the junction point (J), that is inferior to 13 cm, preferably inferior to 11 cm.

7. Ankle holder (200, 200’) according to claims 2 to 6, wherein the first branch (222a) comprises a plantar contacting surface (300) configured to support the foot (F), and wherein the plantar contacting surface is configured to provide an top access angle (304) to the surgical zone that is greater than or equal to 90° when measured around the positioning axis (Y) and between the outer edges of the plantar contacting surface (300).

8. Ankle holder (200, 200’) according to claims 2 to 7, wherein the second branch (222b) comprises a heel contacting surface (302) configured to support the foot, and wherein the heel contacting surface is configured to provide a front access angle (305) to the surgical zone that is greater than or equal to 90° when measured around the heel axis (Z) and between the outer edges of the heel contacting surface (302).

9. Ankle holder (200, 200’) according to claim 1 to 8, wherein the pivoting axis (T) intersects with the pivoting arrangement (223, 223’) and is perpendicular to the longitudinal axis (X).

10. Ankle holder (200, 200’) according to claim 1 to 9, wherein the pivoting axis (T), passes through the ankle (A) and is perpendicular to the longitudinal axis (X).

11. Ankle holder (200, 200’) according to any of the preceding claims, wherein the pivoting arrangement (223, 223’) comprises a locking apparatus (250, 250’) configured to lock a position of the supporting part (222, 222’) with respect to the body part (221, 221’) of the holder (220, 220’).

12. Ankle holder (200, 200’) according to any of the preceding claims, wherein the body part (221) is mobile along the longitudinal axis (X) with respect to the base plate.

13. Ankle holder (200, 200’) according to any of the preceding claims, comprising at least one electromagnetic transmitter (230) configured to emit at least one electromagnetic field, and the electromagnetic transmitter (230) is attached to a flexible element (225) removably secured to the holder (220, 220’), the flexible element (225) being deformable between at least two stable positions.

14. Ankle holder (200, 200’) according to claims 13, wherein the flexible element (225) is configured to be secured to the holder (220, 220’) according to, at least, two different attaching sites (226).

15. Ankle holder (200, 200’) according to claims 13 or 14, wherein the flexible element (225) is secured to the body part (221, 221’) of the holder (220, 220’).

16. Ankle holder (200, 200’) according to claims 13 to 15, wherein the pivoting axis (T) is at a distance from the base plate configured to avoid electromagnetic perturbation of the electromagnetic field emitted by electromagnetic transmitter (230).

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