Independent surgical screw placement system with aiming jig

Abstract

The independent surgical screw placement system utilizes a targeting jig. [Solution] The aiming jig has components and features that can be appropriately adjusted to prevent independent or off-plate screws from intersecting the nominal trajectories of other joint screws that secure the surgical plate to the foot in the relevant surgery. The aiming jig has a telescopic arm that can be adjusted to various potential trajectories for independent surgical screws until a desired trajectory for such independent screw is determined.

Description

Technical Field

[0001] The present disclosure generally relates to systems and devices associated with orthopedic procedures, and more particularly to a system for positioning screws associated with surgical plates related to such surgical procedures.

Background Art

[0002] In various surgical procedures related to foot joints, including the Lisfranc joint and the first tarsometatarsal (TMT) joint, independent screws or extra-plate screws, which are disposed outside the associated plates and their associated joint screws, are often utilized. One of the challenges in positioning such independent screws outside the associated plates involves avoiding the joint screws that are to be, or already have been, disposed through the associated plates. It would be desirable to have a surgical system and related method for improving the placement of independent screws in connection with orthopedic surgery.

Summary of the Invention

[0003] In one suitable embodiment, the present disclosure relates to an independent surgical screw placement system for surgical procedures in foot joints and the like. The system first includes a suitable surgical plate sized to extend over the joint in question, such as a foot joint. Thus, the surgical plate has an upper surface and a lower surface, and a plurality of screw holes positioned to enable the plate to be fixed to adjacent bone, joint, or combinations thereof by the plate or joint screws.

[0004] Multiple articular screws are advanceable into the aforementioned screw holes for fixation to the ankle joint at the corresponding articular location. In this disclosure, the articular screws define their respective nominal trajectories at the ankle joint, and the system is characterized to allow independent surgical screws to be positioned outside the plate and without intersecting the nominal trajectories of the articular screws. The desired positioning of the independent screws is achieved with the assistance of a aiming fixture, which is removablely fixed to the plate.

[0005] In certain embodiments, the independent surgical screw placement system utilizes a connector located between the aforementioned plate and the aiming fixture. This connector may be equipped with features for keying or adjusting the angular orientation of the aiming fixture relative to the plate, for the purpose of later assisting in the desired non-interfering placement of the independent surgical screws. For example, certain embodiments may have the connector in the form of a pilot pin that can mate with opposing pilot holes. Once the pilot pin and pilot hole are mated, the screwable connection can be operated to secure the aiming fixture to the plate.

[0006] In further embodiments, the aiming fixture includes an arm. One end of the arm is located near the plate. The arm extends upward from this first end, i.e., upward from the plate, and then extends either centrally or laterally, depending on the desired trajectory for an independent screw, to terminate at a second end. Thus, the second end of the arm is spaced apart from the plate. The housing is fixed to the second end of the aiming fixture. A screwable connector portion of the connector is located at the first end opposite the arm, for part of its purpose.

[0007] The aiming fixture is characterized by being adjustable by the user to create a user-determined trajectory for an independent screw, preferably a trajectory that does not intersect with the nominal trajectory of any jointed screw. To this end, the arm may include first and second telescopic sections that can be selectively moved and adjusted to position the housing at an angle selected by the user relative to the plate. Such an angle selected by the user is one of the parameters of the user-determined trajectory of the independent screw.

[0008] In a further embodiment, the housing includes three housing apertures, each housing aperture extending between opposing proximal and distal sides. The proximal side is accessible by the surgeon or other user, while the distal side is movably positioned in close proximity to the joint being operated on, such as one of the ankle joints.

[0009] The k-wire tube is also part of the surgical placement system described above and can be placed in any one of the apertures of the housing. Each aperture has its own central axis and is oriented to define an intersection point corresponding to the distal end of an independent screw that can be potentially inserted along a user-determined trajectory. [Brief explanation of the drawing]

[0010] The embodiments described above and their features will be better understood by referring to the description and drawings herein. [Figure 1] This is a perspective view of an independent surgical screw placement system shown for an ankle joint undergoing a surgical procedure. [Figure 2] This is a partial side view showing multiple articular screws within the ankle joint and their corresponding nominal trajectories, as well as independent screws that avoid such nominal trajectories. [Figure 3] This is a partially exploded perspective view of an embodiment of an independent surgical screw placement system. [Figure 4] Figure 3 is a further exploded view of the independent surgical screw placement system. [Figure 5]This is a perspective view of a portion of the independent surgical screw placement system shown in Figures 3 and 4, cut along line 5-5 in Figure 4. [Figure 6] Figures 3 to 5 show an enlarged perspective view of one of the components of the arm of the independent surgical screw placement system. [Modes for carrying out the invention]

[0011] Referring to Figures 1 to 6, in one suitable embodiment of the present disclosure, the independent surgical screw placement system 21 is generally suitable for use in conjunction with a variety of orthopedic surgical procedures, and for surgical procedures related to the foot. In the embodiments illustrated herein, the system 21 is shown for the ankle joint j, in conjunction with surgical procedures related to the ankle joint, such as repair of Lisfranc injury. The system 21 can be used for any number of other procedures involving surgical plates, whether for the foot or for other locations, for example, with the Rapidus procedure.

[0012] In the embodiments shown in Figures 1 and 2, the surgical plate 23 is sized to cover and extend over the ankle joint j, and the plate 23 has an upper surface 25 and a lower surface 27 formed thereon, which are operably connectable to the ankle joint j. The plate 23 has a plurality of screw holes 29 extending through the surfaces 25 and 27 at spaced-apart locations on the plate 23. As shown in Figure 2, a plurality of articular screws 31 are fitted to be received within the screw holes 29 and fixed to the ankle joint j at the corresponding articular locations. The screw holes 29 and screws 31 define a nominal trajectory n, which means that the articular screws 31 extend through the associated screw holes 29 along a trajectory within a standard deviation. Thus, the articular screws 31 advance into the ankle joint j through the screw holes 29 in trajectories that may include various trajectories through the ankle joint j, since they may vary from being strictly perpendicular to the plate 23, and all of these trajectories are considered nominal insofar as they pass through the screw holes 29.

[0013] The surgical screw placement system 21 utilizes a aiming fixture 23, which is removablely fixed to a plate 23 and adapted to be oriented to allow the advancement of an independent screw or a screw 35 outside the plate. The aiming fixture 23 can be adjusted to a user-selectable orientation that does not intersect the nominal trajectory n of the articular screw 31. The aiming fixture 33 can be removablely fixed to the plate 23 in any number of suitable ways before or during a surgical procedure. In the illustrated embodiment, a connector 37 for such purposes is disposed between the plate 23 and the fixture 33. The connector 37 is keyed to allow the user to adjust one of the orientation parameters of the aiming fixture 33. Further parameters of the orientation of the aiming fixture 33, as well as the orientation of the user-selectable trajectory for the independent screw 35, will be described later in this specification.

[0014] The connector 37 utilizes a pilot pin 39 that can be mated with the opposing pilot hole 41 and is secured by a screwable connector 43. In this way, the aiming jig 33 is fixed when the pilot pin 39 and the pilot hole 41 are mated.

[0015] The aiming jig 33 includes an arm 45 having a first end located close to the plate 23, the arm 45 extending from the plate 23 to a second end on which the housing 47 is disposed. A screwable connector 43 is located at the first end of the arm 45 and is connected to the plate 23.

[0016] The arm 45 includes two nesting telescopic sections 49, 51 that vary the overall length of the arm 45 and adjust potential trajectories for independent screws 35 that can be selected by a surgeon or other medical professional. The first nesting telescopic section 49 includes a rail 53 having a defined slot 55 inside. The second nesting telescopic section 51 includes a tongue 57. The tongue 57 is selectively slidable and engageable with a retaining clip 59 formed in the slot 55 of the first nesting telescopic section 49. Buttons 61 are appropriately interconnected between the first nesting telescopic section 49 and the second nesting telescopic section 51 to allow selective nesting of the sections relative to each other and to adjust such sections in the desired extension or retraction using corresponding lengths related to various positions of the retaining clip 59.

[0017] The user-selectable trajectory i of the independent screw 35 can be characterized by a plurality of angular parameters relative to the surgical plate 23. One such angular parameter is a user-selectable angle, which can be generated by selectively moving the nesting telescopic arm portions 49, 51 relative to each other and thereby adjusting them. One such user-selectable angle is shown as an angle Ω relative to the plate 23 (Figure 1). In one suitable embodiment, a user-operable button 61 may be spring-biased to a first position that engages with one of the selected retainers 59, thereby adjusting the nesting telescopic portions 49, 51 relative to each other, including a tongue portion 57 relative to the rail 53. To adjust the user-selectable trajectory i for the independent screw 37 to a new angular trajectory, the button 61 can be actuated to overcome any spring bias, so that the appropriate engaging portion of the button 61 disengages from the previously engaged retaining arm 59, and allows the nesting telescopic portions 49, 51 to nest and extend inward or outward relative to each other, thereby establishing another user-selectable angle Ω with a different angular value relative to the plate 23. The process of adjusting the user-selectable trajectory for the independent screw 35, which includes adjusting the parameter of the user-selected angle Ω formed by the arm 45 relative to the plate 23, can be repeated until the user selects an angular trajectory i and the corresponding selectable angle Ω that avoids intersecting the nominal trajectory n of the articulated screw 31. In the illustrated embodiment, the nesting telescopic portions 49, 51 are in the form of arcs or arched portions. When the arm 45 is connected to the plate 23, such arched portions extend centrally from the connector 37.

[0018] The housing 47 has a distal and a proximal side; that is, the distal side is positioned opposite and movably close to the foot f and ankle j undergoing the relevant surgical procedure. The proximal side is located opposite the distal side, as shown in the figure, and is therefore accessible by the user during the relevant procedure. The housing 47 forms within it at least one housing aperture 63 extending through the proximal and distal sides. In the illustrated embodiment, there are three housing apertures 63 configured for further user-selectable adjustments, as will be described later.

[0019] The aiming fixture 33 includes a appropriately sized k-wire tube 65 that can be received through one or more housing apertures 63 and selectively removed therefrom after the associated operation is completed. Thus, the k-wire tube 71 is sized to have a longitudinally extending k-wire bore 67 that can receive an appropriately sized k-wire. Thus, the k-wire tube 65 can be selectively slid by a user, such as a surgeon, in both the proximal and distal directions relative to the housing 47 to a desired position.

[0020] The aiming jig 33 includes a locking mechanism 69 for adjusting such user-selectable positions of the k-wire tube 65 to desired positions. In the illustrated embodiment, the locking mechanism 69 utilizes a longitudinally extending notch 71 (FIG. 5) formed on the outer surface of the k-wire tube 65. The notch 71 interfaces with a shoulder 73 defined within the k-wire bore 67. The notch 71 and the shoulder 73 are selectively engaged or disengaged by interference fit by a user-accessible handle 75 connected to the k-wire tube 65. Rotation of the handle 75 causes rotation of the notch 71 relative to the shoulder 73 within the k-wire bore 67. The rotated position of the handle 75 can be made observable to the user by providing a handle portion 76 such as an indicator, lever, or tail (as shown) on the handle 75, or by forming the handle of the handle portion, or by appropriate markings indicating the locked or unlocked position of the k-wire tube 65 within the housing aperture 63.

[0021] As seen in FIG. 5, the three apertures 63 of the housing 47 have respective central longitudinal axes K1, K2, K3 that are angled relative to each other to define an off-axis point c that is distally spaced from the housing 47. The arm 45 and its telescoping nested portions 49, 51 allow the housing 47 to be positioned relative to the ankle joint j such that, after insertion into the ankle joint j as a result of a corresponding surgical procedure, the off-axis point c corresponds to the distal end 87 of the independent screw 37.

[0022] In one suitable embodiment as shown in FIGS. 1-3, the surgical plate 23 includes, for example, a dorsal plate 89 adapted to be fixed to and extend over the first tarsometatarsal (TMT) joint in relation to a Lisfranc injury repair procedure. The dorsal plate 89 has a distal surface that may be presented to the ankle joint j during the associated surgical procedure, and a proximal surface on the opposite side of the distal surface, which is adapted to face away from, i.e., upwardly, from the ankle joint j when fixed to the ankle joint j.

[0023] When the surgical screw placement system 21 is adapted for such (TMT) or Lisfranc procedures, the aiming jig 33 is configured such that the housing 47 is positioned approximately at a distance spaced from the central side of the ankle joint j. Such a position enables the aiming jig 33 to have one or more user-selectable trajectories originating from the central side of the ankle joint j, and for this reason, at least one such available trajectory can be selected such that it does not intersect the nominal trajectory n of the articular screw 31.

[0024] For the dorsal plate 89, a plurality of screw holes 29 extend forward from the rear edge portion of the dorsal plate 89. The aiming jig 33 can be removably fixed at at least one location on the dorsal plate 89, behind at least one of the screw holes 29 that extend forward.

[0025] The arm 45 of the aiming jig 33 is formed with an arm tube 77 located at the end of the arm 45 proximate to the dorsal plate 89. The strut shaft 79 is received movably within the arm tube 77. The arm tube 77 and the strut shaft 79 have respective proximal and distal ends that extend coaxially about the longitudinal arm tube axis L.

[0026] The screw-in connection part 43 is disposed and formed at the above-mentioned distal end of the strut shaft 79 and includes a threaded shaft 81 that extends axially and distally therefrom. The mating of the threaded shaft 81 is a corresponding threaded bore 83 formed at a suitable location on the dorsal plate 89, such as a location behind the plurality of screw holes 29. The threaded shaft 81 and the threaded bore 83 together form the screw-in connection part 43.

[0027] The pilot pin 39 is positioned on the distal end of the arm tube 77 and, like the threaded shaft 81, extends longitudinally and distally, but extending from the arm tube 77. A pilot hole 41 is formed on the surface of the dorsal plate 89 at a corresponding location to receive the pilot pin 39 internally, such a corresponding location is adjacent to the threaded bore 83 of the screwable connection portion 43. As shown in the figure, the pilot pin 41 and the threaded shaft 81 extend parallel to each other, so that the arm tube 77 extends substantially perpendicularly from the dorsal plate 89 and is fixed to the dorsal plate. When the portions 49, 51 of the arm 45 are connected to the dorsal plate 89, they extend radially and arc-shaped outward from the longitudinal axis L of the arm tube 77. Therefore, the relative positions of the threaded holes 83 and the pilot holes 41 on the dorsal plate 89 determine the angular orientation Ω of the arm 45 of the aiming jig 33 relative to the plate 89.

[0028] The system 21 further comprises a user-operable support handle 85 connected to the proximal end of the support shaft 79, so that the threaded shaft 81 of the support shaft 79 can be rotated and thus screwed into a threaded bore 83 formed in the back plate 89. The telescopic extension portion 49 of the arm 45 includes a first arched portion 91, and the rail 53 and slot 55 extend over such arched portion 91. The telescopic extension portion 51 of the arm 45 includes a corresponding second arched portion 92, and the tongue 57 and user-operable button 61 are located on such second arched portion 92. Such arrangement allows the arm 45 to be adjusted over a range of angular positions with respect to the reference plane R of the back plate 89. In one suitable embodiment, the slot 55 extends sufficiently so that the range of angular positions can be selected from 60° to 120° with respect to the reference plane R of the back plate 89.

[0029] The operation of the independent surgical screw placement system 21 is evident from the above description in relation to any number of relevant workflows and surgical procedures, including surgical plates on anatomical joints such as the TMT and other ankle joints. In one suitable workflow, the process for inserting an independent surgical screw into the ankle outside of the plate involves adjusting a first location spaced apart from the upper surface of the surgical plate using the adjustable features of the independent surgical screw placement system 21. The adjusted location is located outside the boundary zone, which is defined as the outer edge of the surgical plate. The first location is adjusted to define a first angular orientation relative to the plate. This first angular orientation corresponds to a first potential trajectory, or, considering the three available housing apertures 63, to a set of three trajectories having a common intersection point c, and such trajectories or sets of trajectories are available for use for inserting independent screws outside the plate.

[0030] However, if it is determined that such a first potential trajectory or set of trajectories does not necessarily avoid the nominal trajectories of all articulated screws, such a first location is adjusted by appropriate operation of the aiming fixture 33 to adjust a second location. This second location is also spaced away from the upper surface of the plate and outside the boundary zone defined by the plate, defining a second angular orientation with respect to such a plate.

[0031] Therefore, the second angular orientation corresponds to a second potential trajectory (or, in the case of multiple housing apertures 63, a set of trajectories) of an independent screw for insertion from the outside of the plate. It is then determined whether such a second potential trajectory (or multiple trajectories) constitutes an available trajectory, which means a trajectory that avoids all nominal trajectories of the articulated screw.

[0032] The aforementioned adjustments for different spaced locations with corresponding angular orientations can be repeated until it is determined that one of the potential trajectories constitutes an actually usable trajectory (i.e., a trajectory that avoids the nominal trajectory of the articular screw). Once such a determination of the usable trajectory has been made, the following steps may then be carried out: first, the k-wire is advanced into the ankle joint along the usable trajectory and then removed therefrom. The drill can then be advanced along the path defined by the previously inserted k-wire to form a bore sized to receive the independent screw therein. After the drill has formed a bore of the appropriate size, the independent screw can be advanced into the bore along the usable trajectory.

[0033] As described above, the three housing apertures 63 of the housing 47 make further angular orientations available, and thus provide additional trajectory options when the independent screw searches for the optimal available trajectory that avoids the nominal trajectory for all articular screws. For example, at any adjustable position of the housing 47, the angular orientation of the k-wire tube shaft 65 can be adjusted between one of three different angles by inserting the tube shaft 65 into one of the selected housing apertures 63 (Figure 5). Each of the three different angular orientations shares a common intersection point corresponding to the distal end of the independent screw 35 upon insertion, but at least one of the three such positions can avoid the nominal trajectory of the articular screw, in contrast to another angular orientation of the housing aperture 63 that does not. The handle 75 of the k-wire tube shaft 65 can be used to lock the k-wire tube within the housing aperture 63, and similarly, the bore 67 of the k-wire tube shaft 65 can be moved to a surgical proximity position adjacent to the tissue of the ankle joint being operated on.

[0034] The k-wire tube shaft 65 and its bore 67 are sized to allow the proximal and distal movement of the k-wire and drill along a selected trajectory. However, once the k-wire tube shaft is selected and adjusted for the position of the housing 47, which is adjusted by the aiming fixture 33, the tube shaft 65 and bore 67 prevent the movement of the k-wire and drill from deviating from the available trajectory.

[0035] After the insertion and drilling of the k-wire, the k-wire tube shaft may be removed from one of the corresponding housing apertures 63, and the independent screw 35 may be inserted through such a housing aperture and advanced into the joint outside the plate on a trajectory that avoids intersecting the nominal trajectory of the articular screw.

[0036] Among the advantages of the independent screw placement system 21 and its aiming fixture 33 is that they enhance and optimize the independent or off-plate screw placement for other joint screws associated with surgical plates, particularly plates associated with the Lisfranc or Rapidus procedure.

[0037] A related advantage is that the adjustability of the components of the aiming jig 33 allows surgeons or other practitioners to take into account variability in the patient's anatomical structure.

[0038] It will be further understood that various modifications in the details, materials, and arrangement of the components disclosed herein can be made by those skilled in the art without departing from the spirit and scope of this disclosure. Furthermore, those skilled in the art will understand that the exemplary and disclosed embodiments and their variations are not limiting. It will also be understood that one or more features may be omitted from one or more other alternative embodiments without departing from the scope of this disclosure as set forth in the claims attached to this application.

Claims

1. An independent surgical screw placement system for surgical procedures on the ankle joint, A surgical plate sized to cover and extend over the ankle joint, having a plurality of screw holes extending through the plate on its upper and lower surfaces and at spaced intervals on the plate, A plurality of articular screws, each receiving into the screw hole and adapted to be fixed to the ankle joint at the corresponding joint location, comprising a plurality of articular screws defining their respective nominal trajectories within the ankle joint, A system comprising: an aiming fixture that is removablely fixed to the plate, and is adapted to be adjustable to a user-selectable trajectory for the independent screw that does not intersect the nominal trajectory of the articulated screw.

2. The system according to claim 1, further comprising a connector disposed between the plate and the aiming jig, wherein the connector is keyed to adjust the angular orientation of the aiming jig relative to the plate.

3. The system according to claim 2, wherein the connector comprises a pilot pin that can be fitted into opposing pilot holes, and a screwable connector that can operate to fix the aiming jig to the plate when the pilot pin and the pilot hole are fitted together.

4. The aiming jig includes an arm having a first end located on the plate, the arm extending from the plate to a second end, and the second end terminating within a housing. The screwable connection portion of the connector is disposed at the first end of the arm, The user-selectable trajectory of the independent screw is characterized by a plurality of angular parameters relative to the plate, The system according to claim 1, wherein the arm includes first and second nesting extension portions, the nesting extension portions being located between the first end and the second end of the arm and extending therefrom, the nesting extension portions being selectively movable and adjustable to position the housing at a user-selectable angle relative to the plate, the user-selectable angle constituting one of the parameters of the user-selectable trajectory of the independent screw.

5. The first nesting extension portion comprises a longitudinally extending rail having a longitudinally extending slot defined inside, and the second nesting extension portion defines a tongue portion that slidably receives within the slot. The rail has a plurality of stoppers defined adjacent to the slot and spaced apart in the longitudinal direction, The system according to claim 4, wherein the tongue includes a user-operable button, the button having a first position for engaging one of the selected stoppers for adjusting the rail and the tongue relative to each other, and the button having a second position for disengaging from the stoppers for the nesting extension portions to nest and extend relative to each other.

6. The system according to claim 5, wherein the nesting expandable portion comprises an arc-shaped portion extending from the connector toward the center.

7. The housing comprises a distal side and a proximal side, wherein the distal side is positioned to face and be movably close to the foot associated with the ankle joint when the procedure is performed, and the proximal side is positioned to be accessible to the user during the procedure. The housing further comprises at least one housing aperture extending through the side, The system according to claim 4, wherein the aiming fixture further comprises a k-wire tube that is removablely receivable through the housing aperture, the k-wire tube having a longitudinally extending k-wire bore sized to receive a k-wire.

8. The k-wire tube is selectively slidable in the proximal and distal directions relative to the housing to a desired position. The system according to claim 7, wherein the aiming jig includes a locking mechanism for adjusting the k wire tube to the desired position.

9. The locking mechanism comprises a longitudinally extending notch defined within the outer surface of the k wire tube, and the locking mechanism further comprises a shoulder defined within the k wire bore and a handle disposed at the proximal end of the k wire tube, wherein the handle is connected to the k wire tube such that rotation of the handle causes rotation of the notch within the bore relative to the shoulder. The system according to claim 8, wherein sufficient rotation of the handle relative to the shoulder portion selectively locks and unlocks the k-wire tube at the desired position, and the handle further includes a portion that indicates whether the corresponding k-wire tube is in the locked position or the unlocked position.

10. The system according to claim 7, further comprising three of the housing apertures, each of which has its own central axis, the axes being angled relative to one another to define an intersection point distally separated from the housing, and the housing being installable relative to the foot of the ankle joint after being inserted into the ankle joint during the procedure, such that the intersection point corresponds to the distal end of the independent screw.

11. The surgical plate comprises a dorsal plate, which is fixed to a first tarsometatarsal joint in connection with a Lisfranc injury repair procedure and is fitted to extend over and cover the first tarsometatarsal joint, the dorsal plate having a distal surface that can be brought toward the ankle joint during the procedure, and a proximal surface opposite to the distal surface and fitted to face away from the ankle joint when fixed to the ankle joint, The system according to claim 4, wherein the aiming fixture is adapted to position the housing above the central side of the ankle joint, and the aiming fixture is adapted to have the user-selectable trajectory starting from the central side.

12. The system according to claim 11, wherein the screw holes extend forward, and the aiming jig can be detachably fixed to at least one location on the back plate behind at least one of the screw holes.

13. The arm of the aiming jig comprises an arm tube at the first end of the arm and a support shaft movably received within the arm tube. The arm tube and the support shaft each have a proximal and distal end, and are coaxial with respect to the longitudinal axis of the arm tube. The screwable connection portion comprises a threaded shaft disposed at the distal end of the support shaft and extending longitudinally from the distal end of the support shaft, and the screwable connection portion further comprises a corresponding threaded bore formed in the back plate at a location behind a plurality of the threaded holes. The pilot pin is disposed on the distal end of the arm tube and extends longitudinally and distally from the arm tube. The pilot hole is formed on the proximal surface of the back plate adjacent to the threaded bore of the screwable connection portion. The pilot pin and the threaded shaft extend parallel to each other, so that when the arm tube is fixed to the dorsal plate, it extends perpendicularly from the proximal surface of the dorsal plate. When the telescopic extension portion of the arm is connected to the plate, it extends radially and outward in an arc shape from the longitudinal axis of the arm tube. The system according to claim 12, wherein the relative location of the threaded bore in the back plate and the pilot hole in the back plate determines the angular orientation of the arm of the aiming fixture with respect to the plate.

14. The system according to claim 13, further comprising a user-operable support handle connected to the proximal end of the support shaft, for screwing the threaded support of the support shaft into the threaded bore of the plate.

15. The rail and the slot are located on one of the arched portions, and the tongue and the user-operable button are located on the other of the arched portions such that the second end of the arm retracts and contracts through a range of positions angled with respect to the reference plane of the plate, The system according to claim 6, wherein the slot extends sufficiently so that the angled position range extends from 60° to 120° with respect to the reference plane associated with the plate.

16. A process for inserting independent surgical screws into ankle joints outside a plate, wherein the plate has an upper and lower surface having screw holes extending through the plate in spaced-out locations covering a surgical area, the plate has articular screws extending through the screw holes for fixing the plate to the ankle joint, the articular screws defining respective nominal trajectories within the ankle joint, the surgical area having an outer edge, the outer edge defining a boundary zone extending outward from the upper surface of the plate and spreading into the same space as the outer edge, and the process is, Adjust a first location spaced apart from the upper surface of the plate and located outside the boundary zone, and define a first angular orientation relative to the plate, which corresponds to a first potential trajectory of the independent screw for insertion outside the plate, Determining whether the first potential trajectory constitutes a first available trajectory by avoiding all of the nominal trajectories of the articular screw, If the first potential trajectory does not necessarily avoid all of the nominal trajectories of the articular screw, adjust the first spaced location to adjust the second location spaced from the upper surface of the plate, located outside the boundary zone, and define the second angular orientation relative to the plate, which corresponds to the second potential trajectory of the independent screw for insertion outside the plate. Determining whether the second potential trajectory constitutes a second available trajectory by avoiding all of the nominal trajectories of the articular screw, If it is determined that one of the potential trajectories constitutes the available trajectory, The steps include advancing the k-wire into the ankle joint along the available trajectory, and then removing the k-wire from the ankle joint, The steps include advancing the drill into the ankle joint along the available trajectory to form a bore sized to receive the independent screw into the ankle joint, and then removing the drill, A process comprising the steps of: advancing the independent screw into the bore along the available track to insert the independent screw out of the plate.

17. A step of determining the intersection point in the ankle joint corresponding to the endpoint of the independent screw to be inserted, If the second potential trajectory is not determined to constitute an available trajectory, the steps include rotating the second angular orientation to a different angle with respect to the intersection point in order to define a third angular orientation which corresponds to a third potential trajectory for inserting the independent screw outside the plate, The process according to claim 16, further comprising the step of determining whether the third potential trajectory avoids all of the nominal trajectories of the articular screw.

18. The step of rotating the second angular orientation includes selecting a potential rotational position relative to the intersection point from three rotational positions available at the first and second locations relative to the intersection point, The steps include determining whether the selected potential rotational position constitutes an available trajectory by avoiding all of the nominal trajectories of the articulated screw, If so, the process according to claim 17, comprising the step of adjusting the available trajectory for subsequent insertion of the independent screw.

19. The process according to claim 16, wherein during the step of advancing the k-wire, the k-wire is physically prevented from moving away from the available trajectory, thereby maintaining the resulting pilot hole that forms the k-wire within the nominal range.

20. The process according to claim 16, further comprising the step of adjusting the spaced portion of the ankle joint toward the foot to define an adjacent portion that is movably close to the tissue adjacent to the ankle joint.

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