Implant, drill guide, modular system

Abstract

Implant for use in tibial plateau leveling osteotomy (TPLO) surgery, particularly for a dog or cat, wherein the implant (10) is attached to the tibial body, particularly to a medial surface (58) of the tibia (20), and to the tibial head (44) after circular segment-shaped incision and rotation of a caudal fragment (46) by screws (62a, 62b) through screw holes (64a, 64b) extending along a screw hole axis (a, a1, a2, a3) from a medial surface (12) to a lateral surface (14), comprising a proximal head section (24), a cranial section (28) and a caudal process (26).

Description

[0001] The invention relates to an implant for use in TPLO (Tibial Plateau Leveling Osteotomy) surgery, a drill guide that guides and positions a drill on the tibia, and a modular system comprising such an implant.

[0002] Tibial Plateau Leveling Osteotomy (TPLO) is a specialized orthopedic procedure used to treat cranial cruciate ligament (CCL) injuries in dogs, similar to anterior cruciate ligament (ACL) injuries in humans. The CCL plays a crucial role in stabilizing the knee joint, and a complete or partial tear can lead to pain, lameness, and long-term joint problems such as osteoarthritis.

[0003] The TPLO procedure aims to reshape the dynamics of the dog's knee so that the torn or weakened ligament is no longer needed to stabilize the joint under load. This is achieved by making a circular incision in the tibia and rotating the upper segment, known as the tibial plateau, until its angle to the rest of the tibia is altered. The tibial plateau includes the lateral and medial tibial condyles. The repositioned tibial plateau is then stabilized with an implant and screws to allow the bone to heal in its new configuration.

[0004] WO 2022 / 182987 A1 shows an orthopedic spacer arrangement with a bone plate and a spacer for TPLO.

[0005] US 2021 021 27 38 describes a TPLO plate for stabilizing the knee joint in animals after injuries to the cranial cruciate ligament.

[0006] US 11,317,953 describes a TPLO bone plate that includes one or more suture loops to improve the rotational stability of the joint or bone and to facilitate the reattachment of soft tissue to the plate at anatomical locations.

[0007] The object of the invention is to improve the state of the art in TPLO with regard to the reattachment and stabilization of the detached segment of the tibial head to the tibia.

[0008] This problem is solved by an implant for use in TPLO (Tibial Plateau Leveling Osteotomy) surgery, particularly for a dog or cat, according to claim 1. The implant can be attached to the tibial body, particularly to a medial surface of the tibia, and to the tibial head after a circular segment-shaped sectioning and rotation of a caudal fragment using screws through screw holes extending along a screw hole axis from a medial surface to a lateral surface. The sectioning is performed with a circular saw blade having a radius. The sectioned caudal fragment of the tibial head comprises at least the lateral and medial tibial condyles, preferably the entire tibial plateau.

[0009] The implant includes: - a proximal head section that can be attached to the caudal fragment, - a cranial process is provided in a distal and / or cranial direction on a cranial side of the head section, - A caudal process extending distally is provided on the caudal side of the head section.

[0010] The cranial extension of the implant can be attached to a medial-cranial surface of the tibial body and / or a medial-cranial surface of an uncut cranial tibial head fragment. The caudal extension of the implant can be attached to a medial surface of the tibial body.

[0011] This implant provides improved stability and reattachment of the severed and rotated caudal fragment, leading to better healing in the animal. Patients have been shown to recover more quickly from TPLO when an implant according to this invention is used compared to conventional implants. Because two processes are incorporated, the overall length of the implant in the proximal-distal direction is shorter than with conventional TPLO implants, thus requiring a smaller incision and minimizing disruption to surrounding tissue.

[0012] Preferably, both the caudal and cranial processes are provided on the proximal head section, with the two processes being spaced apart from each other. Furthermore, the implant is preferably U-shaped, V-shaped, or hook-shaped, with the two arms formed by the processes.

[0013] The cut can be made with saw blades of varying radii. Ideally, the implant is matched to the radius. An implant can be provided for each saw blade and radius. A specific method for planning the TPLO surgery can be used, in which the saw blade size is selected before the operation, followed by the corresponding implant. There can be nine saw blade radii available, e.g., 10, 12, 15, 18, 20, 21, 27, 30, and 33 mm, with the implants potentially having a laser marking corresponding to the planned cut radius. Furthermore, it is advantageous to have right-handed implants for the right knee and left-handed implants for the left knee.

[0014] The head section can have an arc-shaped configuration enclosing an angle of approximately 180° and comprising a first and a second end section, with the cranial process adjoining the first end section and the caudal process adjoining the second end section. The end sections may extend to the tibial incision line if the implant is attached to the tibia.

[0015] It is conceivable that the caudal process has a first section that connects to the head portion and runs at least largely parallel to the cranial process. This allows for better adaptation to the anatomy of the tibia. However, it may not run parallel; for example, the cranial process may extend further cranially depending on the patient's anatomical characteristics.

[0016] It is advantageous if the caudal process has a second section adjoining the first section, the second section being located away from the proximal head section, the first and second sections lying along different straight lines, on a circular path, and / or forming an obtuse angle. The obtuse angle is advantageously in the range of 100° to 140°.

[0017] It has proven advantageous if the caudal process has a greater distal extension than the cranial process.

[0018] It is conceivable that the implant is manufactured using 3D printing and that at least two screw holes are provided with a teardrop-shaped thread arrangement with a single tip, the tips of all holes pointing in the same distal direction. The thread arrangement can be designed as a true thread or, preferably, as a thread arrangement consisting of largely parallel thread elements.

[0019] A circular marking with a radius that is largely equal to the radius of the circular segment-like cut is provided on a medial surface of the implant. Such a marking can be located between the head section and the processes or on the processes themselves.

[0020] Advantageously, the implant has at least one screw hole each in the head section, the caudal process, and the cranial process. Furthermore, it is advantageous if at least one screw hole is provided in the head section, and at least one of these screw holes is threaded.

[0021] Furthermore, it is conceivable that at least one screw hole is provided in the cranial process and / or the caudal process, with at least one screw hole being equipped with a threaded or ramped arrangement. Additionally, three screw holes may be provided in the head section, three screw holes in the caudal process, and two screw holes in the cranial process. Alternatively, three screw holes in the head section, two screw holes in the caudal process, and one screw hole in the cranial process with a threaded arrangement may be provided.

[0022] It has proven advantageous to have a screw hole in the cranial process and / or a screw hole in the caudal process equipped with a ramp arrangement.

[0023] Furthermore, it is advantageous if each ramp arrangement is provided with an inclination extending along an axis of inclination, wherein the axis of inclination is directed towards an anatomical center point located at an anatomical point of the center of the circular segment-like cut with which the tibial head is cut, the axis of inclination intersecting at this anatomical center point.

[0024] The ramps are advantageously designed such that when a screw is inserted into the screw hole with the ramp and tightened, the screw head, brought into contact by the tightening, exerts a force with a force direction through the anatomical center or along a central axis directed medially to laterally through the anatomical center. This results in better compression of the caudal fragment on the tibia and thus in improved fixation and rehabilitation.

[0025] The head section can include a cranial screw hole, a caudal screw hole, and a proximal screw hole located between the cranial and caudal screw holes. The axis of the cranial screw hole forms an angle with the sagittal plane in the proximal-distal direction of 97°–87°, preferably 92°. The axis of the proximal screw hole forms an angle with the sagittal plane in the proximal-distal direction of 89°–79°, preferably 84°. The axis of the caudal screw hole forms an angle with the sagittal plane in the proximal-distal direction of 92°–82°, preferably 87°. These angles, commonly referred to as the vertical direction (proximal-distal direction), provide better fixation of the screws to the tibia and reduce the risk of tibial bone avulsion.Furthermore, these angles largely ensure that the screws do not penetrate the joint surfaces and are fixed in areas of the tibia with largely sufficient bone substance.

[0026] The head section can include a cranial screw hole, a caudal screw hole, and a proximal screw hole located between the cranial and caudal screw holes. The axis of the cranial screw hole forms an angle with the sagittal plane in a caudal-cranial direction of 91°–105°, preferably 96° or 100°. The axis of the proximal screw hole forms an angle with the sagittal plane in a caudal-cranial direction of 88°–98°, preferably 93°. The axis of the caudal screw hole forms an angle with the sagittal plane in a caudal-cranial direction of 82°–67°, preferably 77° or 72°. These angles, commonly referred to as the horizontal direction (caudal-cranial direction), provide better fixation of the screws to the tibia and reduce the risk of tibial bone avulsion.Furthermore, these angles largely ensure that the screws do not penetrate the joint surfaces and are fixed in areas of the tibia with largely sufficient bone substance.

[0027] Advantageously, the shape of the lateral surface is organically structured, corresponding to the tibia to which it is to be attached. This means the implant does not need to be bent into the desired shape to fit well on the medial surface of the tibia.

[0028] A drill guide for guiding and positioning a drill bit when drilling into the tibia also solves the problem of the invention. The bore is provided for fastening the implant according to the invention with a non-locking screw through one of the screw holes, which are equipped with a ramp arrangement. The drill guide comprises: - a bolt with a threaded section and a section for fastening in a threaded screw hole, which is provided near the screw hole with a ramp arrangement, and - a drill guide piece with a section attachable to the bolt for guiding a drill, wherein the drill is guided perpendicular to the screw hole with the ramp arrangement when the drill guide is attached to the bolt.

[0029] The mounting section is preferably round, so that the drill guide piece can be attached omnidirectionally to the S mounting section.

[0030] The drill guide makes drilling screw holes safer for the patient and improves recovery.

[0031] A modular system also solves the problem of the invention. The modular system comprises a plurality of implants according to the invention. The modular system can also include a drill guide according to the invention. The multiple implants can differ in size for the dog breed on which the operation is to be performed and / or in the saw blade radius used to remove the tibial plateau. Furthermore, it is advantageous if the modular system provides right-handed implants for the right knee joint and left-handed implants for the left knee joint.

[0032] A combination of several of the aforementioned features results in a highly advantageous implant. With its two projections, the implant allows for both craniodistal and distal compression simultaneously. Due to its geometry, the implant is shorter than currently available implants on the market. This allows the implant to better counteract rotational forces and enables effective craniodistal compression. Its highly anatomical design, laser marking, and availability of a plate for each blade size are further advantages.

[0033] The overall geometry of the implant makes it much more robust, stable, and shorter compared to the state of the art for the same type of implant used in TPLO surgery. The implant allows for two compressions in different directions, instead of one in previous implants: the first compression is craniodistal (cranial) and the second is proximodistal (distal). Another advantage of this implant is that the screws can be widely spaced, minimizing the plowing effect because the lever arm opposing the forces is large. This also minimizes the risk of screw pullout.

[0034] With the implant, drill guide and modular system, the TPLO operation can be advantageously improved in a wide variety of dog breeds, from a small dog breed like a Chihuahua to a large dog breed like a Spanish Bulldog.

[0035] Further details and advantageous embodiments of the invention can be found in the following description, which provides further description and explanation of exemplary embodiments of the invention.

[0036] They show: Fig. 1 and Fig. 2: An implant from different perspectives; Fig. 3: a circular saw blade that cuts through the tibial head; Fig. 4: the implant according to Fig. 1 and Fig. 2, positioned on the according to Fig. 3 cut tibial head and tibial body; Fig. 5: a drill guide attached to the implant according to Fig. 4 is attached and a drill is inserted into it; Fig. 6: the implant according to Fig. 4 and Fig. 5, which is partially attached to the tibia body and the cut tibia head; Fig. 7 and Fig. 8: the implant with a schematic section and the anatomical center of the section from different perspectives; Fig. 9: Angles of the screw hole axes to the sagittal plane from a caudal perspective; and Fig. 10: The angles of the screw hole axes to the sagittal plane form a proximal perspective.

[0037] An implant 10 for use in TPLO surgery (Tibial Plateau Leveling Osteotomy) is in Fig. 1 and Fig. 2 shown from different perspectives. Fig. Figure 1 shows implant 10 from a medial perspective and Fig. Figure 2 shows the implant from a more cranial-proximal perspective compared to Fig. 2. This particular embodiment is intended for the right knee joint of a dog, but all the following descriptions are also applicable to a left-sided embodiment of the implant 10. Embodiments for other animals are also possible. The implant 10 has a flat shape with a medial surface 12 and a lateral surface 14, the lateral surface being Fig. 9 and Fig. 10 is better represented.

[0038] In Fig. 1 and Fig. Figure 2 shows a coordinate system for better orientation of the implant 10, with the directions proximal pr, distal di, cranial cr, caudal ca, lateral la, and medial me. The orientation of Fig. 1 also applies to the following Fig. 4 and the orientation of Fig. 2 applies to the Fig. 3, Fig. 5 and Fig. 6, wherein the Fig. Figures 3 to 6 show a right-sided knee joint 16 with the femur 18 and the tibia 20. Fig. Figure 4 also shows the fibula 22.

[0039] Based on the Fig. 1 and Fig. Section 2 describes the general shape of the implant 10. The implant 10 consists of a proximal head section 24, a cranial process 26, and a caudal process 28. The cranial process 26 and the caudal process 28 are separate and connected by the head section 24. A possible imaginary boundary 30, represented by a dashed line, indicates the area where the head section 24 ends and the processes 26 and 28 begin.

[0040] The head section 24 has an arc-shaped configuration enclosing an angle of approximately 180° and comprising a first end section 32 and a second end section 34, with the cranial process 28 adjoining the first end section 32 and the caudal process 26 adjoining the second end section 34. The caudal process 26 has a first section 36 adjoining the head section 24 and running at least largely parallel to the cranial process 28. Furthermore, the caudal process 26 has a second section 38 adjoining the first section 36 and extending away from the proximal head section 24, with the first section 36 and the second section 38 forming an obtuse angle α. The first section 36 and the second section 38 also form a circular path, as the overall shape of the implant 10 is organic.It can be seen that the caudal process 26 has a greater distal extension than the cranial process 28.

[0041] Furthermore, the implant can be described as U- or V-shaped or hook-shaped, with the two separate legs being formed by the processes 26, 28.

[0042] The implant 10 has several screw holes 64a, 64b, each extending along a screw hole axis a from the medial surface 12 to the lateral surface 14; the configuration of the different screw hole axes is described below with reference to the Fig. 9 and Fig. 10 explained.

[0043] Fig. Figure 3 shows the knee joint 16 with a circular saw blade 40 having a radius r between the cutting line c and its central axis m from a medial perspective. Normally, in TPLO surgery, access is gained from the medial side. Using the saw blade 40, a circular cut 42 is made in the tibial head 44 to separate a caudal fragment 46 from the tibial head 44, which includes the tibial condyle plateau 48 with the medial tibial condyle 50 and the lateral tibial condyle 52. The cut 42 separates the tibial head 44 into the caudal fragment 46 and an uncut cranial tibial head fragment 54. The cut 42 has the same radius r as that of the circular saw blade 40 used.

[0044] The incision 42 can be made with saw blades 40 of various radii. The implant 10 used later is matched to the radius. One implant 10 can be provided per saw blade 40 and corresponding radius r in a set or set of saw blades. This can be a special method for planning the TPLO operation, in which the saw blade size (radius r) and the corresponding implant 10 are selected before the TPLO operation.

[0045] There can be nine saw blade radii r, for example, but not limited to, the radius r can be 10, 12, 15, 18, 20, 21, 27, 30, and 33 mm, as these radii have proven suitable for the most common dog breeds. The implants 10 can be marked with a laser marking corresponding to the radius r of the planned cut 42.

[0046] Furthermore, it is advantageous if right hand implants 10 are intended for the right knee joint 16 and left hand implants 10 for the left knee joint 16. The right-sided implants 10 are in the Fig. 1, Fig. 2, Fig. 4, Fig. 5, Fig. 6, Fig. 9 and Fig. 10 are shown. The left-sided implants 10 are in the Fig. 7 and Fig. 8 shown.

[0047] Fig. Figure 4 shows the tibia 20 with a gap 56 between the caudal fragment 46 and the cranial fragment 52, where the cut 42 according to Fig. 3 was carried out. The cut 42 lies on the circular cutting line c with its center on the central axis m with radius r. The circle c has the same radius r as that of the circular saw blade 40.

[0048] The caudal fragment 46 is rotated about its center point m in the caudal direction by an angle β. The implant 10 is roughly positioned on the medial surface 58 of the tibia 20, with its lateral surface 14 at least partially touching the tibia. The implant 10 is not yet fixed to the tibia 20. It can be seen that the implant 10 is not yet in its final position, as a marking 60 on the implant 10's medial surface 12, which corresponds to the radius r, is not yet fully positioned on the section 42. In addition to the marking 60, the radius r can be written on the implant in millimeters.

[0049] The Fig. 5 and Fig. Figure 6 shows the attachment of the implant 10 to the tibia with screws 62a, 62b through the screw holes 64a, 64b. Various locking screws 62a and non-locking screws 62b are provided for this attachment. Corresponding screw holes 64a, 64b are provided for the screws 62a, 62b, with screw holes 64a having a threaded arrangement 66 for the locking screws 62a and screw holes 64b having a ramp arrangement 68 for the non-locking screws 62b. The various screw holes 64a, 64b are also shown in the other figures of the implant 10, in particular in the Fig. 1 and Fig. 2.

[0050] In the embodiment according to the Fig. Figures 1, 2, 4-10 state that the implant 10 has three screw holes 64a with a threaded arrangement 66 in the head section 24. One screw hole 64a is provided at a distal point of the cranial process 28 and two screw holes 64a in the caudal process 26, with one screw hole 64a being provided at a distal point of the first section 36 and one at a distal point of the second section 38. It is preferred that the screw holes 64a with a threaded arrangement 66 are conical.

[0051] Regarding the screw holes 64b with the ramp arrangement 68, one screw hole 64b is provided in the caudal extension 26 and one in the cranial extension 28. The screw hole 64b of the caudal extension 26 is located in the first section 36.

[0052] In this embodiment, which is best described in the Fig. 1 and Fig. As shown in Figure 2, each screw hole 64b is connected to the nearest screw hole 64a by a ramp arrangement 68 and a thread arrangement 66, such that the two screw holes 64a and 64b form a figure-eight opening. Screw hole 62a is located distal to screw hole 64b.

[0053] However, other configurations of the screw holes 64a, 64b are also conceivable, for example, only two or four screw holes 64a in section 24, more than one screw hole 64b in each of the processes 26, 28, and more screw holes 62a in the processes 26, 28. In addition, other positions of the screw holes 64a, 64b are also possible, depending on the anatomical conditions for the desired TPLO.

[0054] In Fig. Furthermore, a K-wire 70 is inserted into a K-wire hole 72 in the caudal process 26 through the implant 10 into the tibia 20 to stabilize and hold the implant 10 in position, even if it is not fully fixed to the tibia 20 by screws 62a, 62b. A second K-wire hole 74 is provided in the head section 24. Additional K-wire holes may also be provided in the implant 10.

[0055] To secure the implant 10, three locking screws 62a are first inserted into the designated screw holes 64a after a hole has been drilled into the caudal fragment 46. The screws 62a are each tightened until the locking head is inserted into the threaded assembly 66, which securely fastens the implant 10 to the caudal fragment 46.

[0056] After the head section 24 of the implant 10 has been secured by tightening the three screws 62a in the head section 24, the holes for the non-head-locking screws 62b are drilled into the tibia 20. To drill suitable holes, a drill guide 76 is used to guide and position a drill 78.

[0057] The drill guide 76 consists of a bolt 80 with a threaded section 82 and a mounting section 84, and a drill guide piece 86 with a guide section 88 for the drill 78. The bolt 80 is screwed into the screw hole 62a with its threaded assembly 66 of the cranial extension 28 with its threaded section 82. The drill guide piece 86 is attached to the mounting section 84. The mounting section 84 is round, so that the drill guide piece 86 can be attached to the bolt 80 in any direction. The drill guide piece 86 can be attached to and removed from the bolt 80 by means of a clip-type section 90. The section 88 is shaped like a cylindrical hole with a diameter corresponding to the diameter of the drill 78 used, passing through the entire drill guide piece 86.The drill guide 76 is designed such that the guide section 88 aligns with the screw hole axis a of the respective screw hole 64b, thus aligning the drill bit 78 with the screw hole axis a. This makes drilling the holes for the non-locking screws 62b easier and safer, since it is not possible to permanently attach a drill guide to the screw holes 64b using the ramp arrangement 68.

[0058] An additional section for the drill guide 92 can be provided in the bolt 80, which guides the drill 78 when drilling the holes for the head locking screws 62a into the tibia 20. It is conceivable to provide several bolts 80 and / or drill guide pieces 86 for guiding drills 78 with different diameters.

[0059] Furthermore, the bolt 80 and the drill guide piece 86 can be one piece.

[0060] In Fig. Figure 6 shows the knee joint 16 with the implant 10 after the screws 62a, 62b were tightened. In particular, the non-head-locking screw 62b was inserted into the screw hole 64b of the cranial process 28 and tightened, resulting in compression of the caudal fragment 46 on the tibia 20 along the incision 42, with the gap 56 ( Fig. 4) is no longer available.

[0061] The compression results from tightening the non-head-locking screw 62b in the screw hole 64b against the ramp assembly 68. The ramp assembly 68 is provided with an inclination 94, which extends along an inclination axis sa ( Fig. 7, Fig. 8) in a proximal direction. When you tighten screw 64b, the head of screw 64b presses against the ramp section 68 and slides down the inclination 94, thereby moving the implant 10 with the attachable caudal fragment 46 in a distal or distal-cranial direction. This movement continues until the screw head comes to rest at a proximal end of screw hole 64b, because the screw holes 64b are slotted. The movement of the implant 10, and thus also of the attachable caudal fragment 46, results in a force f along the respective inclination axis sa of the screw holes 64b.

[0062] The operating principle of the compression of the screw holes 64b with the ramp arrangement 68 and the non-head-locking screws 62a is explained by means of the Fig. 7 and Fig. Figure 8 is better explained, as the bone structure of the knee joint 16 is not shown there. The section line c in the medial-lateral direction, the central axis m, and the implant 10 are each shown. Furthermore, the anatomical center point p of section 42 within the joint 16 is shown. Here it can be seen that the forces f run along the axes sa, with the inclination axes sa intersecting at the anatomical center point p. Therefore, each of the forces f acts on the anatomical center point p. The inclination axes sa are preferably arranged such that they are not coplanar to each other, and consequently, neither are the forces f. Fig. 8 is a plane parallel to the anatomical sagittal plane added as a reference for the alignment of the implant 10.

[0063] In the Fig. 9 and Fig. Figure 10 shows another aspect of the implant 10. In order to improve the attachment of the head section 24 to the caudal fragment 46, which leads to better compression of the caudal fragment 46 on the tibia 20, the axes of the three screw holes 64a provided in the head section 24 are arranged at certain angles to the sagittal plane or a plane parallel to the sagittal plane.

[0064] Fig. Figure 9 shows the implant from a caudal-cranial perspective, with the respective screw hole axes a1, a2, a3 shown for all screw holes 62a provided in the head section 24. The screw hole axis a1 of the cranial screw hole 64a forms an angle γ1 of 92° with the sagittal plane in the distal direction of the cranial screw hole axis, whereby the angle γ1 can be in the range of 97–87°. The screw hole axis a2 of the proximal screw hole 64a forms an angle γ2 of 84° with the plane st in the distal direction, whereby the angle γ2 can be in the range of 89–79°. The screw hole axis a3 of the caudal screw hole 64a forms an angle γ3 of 87° with the plane st in the distal direction, whereby the angle γ3 can be in the range of 92-82°.

[0065] Fig.Figure 10 shows the implant from a proximal-distal perspective. The respective screw hole axes a1, a2, and a3 are shown for all screw holes 62a provided in the head section 24. The screw hole axis a1 of the cranial screw hole 64a forms an angle γ4 with the plane st in the cranial direction of 96° or 100°, with the angle potentially ranging from 91° to 105°. The screw hole axis a2 of the proximal screw hole 64a forms an angle γ5 with the plane st in the cranial direction of 93°, with the angle potentially ranging from 88° to 98°. The screw hole axis a3 of the caudal screw hole 64a forms an angle γ6 with the plane st in the distal direction, wherein the caudal screw hole axis forms an angle with the sagittal plane in the plane st in the cranial direction of 77° or 72°, the angle being able to be in the range of 82-67°.

[0066] With the angles γ1, γ2, γ3, γ4, γ5, γ6, which include the aforementioned values ​​or ranges, a favorable fixation of the implant 10 can be ensured.

[0067] The implant 10 can be manufactured using rapid prototyping, particularly by 3D printing with a biocompatible metal such as titanium. For improved quality, the threaded arrangements 66 in the screw holes 64a can consist of several superimposed parallel elements resembling a thread, but without the usual thread pitch. Furthermore, for improved manufacturability, the screw holes 64a with this threaded arrangement 66 are teardrop-shaped with a tip 96, the tips 96 of all holes pointing in the same distal direction.

[0068] Overall, TPLO surgery can be improved with an implant 10 and a drill guide 76 or a modular system of several implants 10. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] WO 2022 / 182987 A1

[0004] US 2021 021 27 38

[0005] US 11,317,953

[0006]

Claims

[1] Implant (10) for use in tibial plateau leveling osteotomy (TPLO) surgery, particularly for a dog or cat, wherein the implant (10) can be attached to the tibial body, particularly to a medial surface (58) of the tibia (20), and to the tibial head (44) after circular segment detachment and rotation of a caudal fragment (46) by means of screws (62a, 62b) through screw holes (64a, 64b) extending along a screw hole axis (a, a1, a2, a3) from a medial surface (12) to a lateral surface (14), comprising: - a proximal head section (24) that can be attached to the caudal fragment (46), - a cranial extension (28) is provided in a distal and / or cranial direction on a cranial side of the head part (24), - a caudal process (26) is provided in a distal direction on a caudal side of the head section (24), wherein the cranial process (28) can be attached to a medial-cranial surface of the tibial body and / or a medial-cranial surface of an undetached cranial tibial head fragment, wherein the caudal process (26) can be attached to a medial surface of the tibial body. [2] Implant (10) according to claim 1, wherein the head section (24) is arc-shaped, encloses an angle of about 180° and has a first end section (32) and a second end section (34), wherein the cranial extension (28) connects to the first end section (32) and the caudal extension (26) connects to the second end section (34). [3] Implant (10) according to claim 2, wherein the caudal extension (26) has a first section (36) which connects to the head section (24) and runs at least largely parallel to the cranial extension (28). [4] Implant (10) according to claim 3, wherein the caudal extension (26) has a second section (38) which adjoins the first section (36) and is spaced apart from the proximal head section (24), wherein the first section (36) and the second section (38) are arranged along different straight lines, lie on a circular path and / or enclose an obtuse angle (α). [5] Implant (10) according to any of the preceding claims, wherein the caudal extension (26) has a greater distal extension than the cranial extension (28). [6] Implant (10) according to one of the preceding claims, wherein the implant (10) is manufactured using 3D printing and wherein at least two screw holes with a threaded arrangement (66) are provided and have a teardrop shape with a tip (96), wherein the tips (96) of all screw holes (64a) point in the same distal direction. [7] Implant (10) according to one of the preceding claims, wherein a circular marking (60) with a radius (r) is provided on a medial surface (12) of the implant (10), wherein the radius (r) is the same as the radius (r) of the circular segment-like cut (42). [8] Implant (10) according to any of the preceding claims, comprising at least one screw hole (64a, 64b) in each of the head sections (24), the caudal process (26) and the cranial process (28). [9] Implant (10) according to one of the preceding claims, wherein at least one screw hole (64a, 64b) is provided on the head section (24), wherein at least one screw hole (64a) is provided with a threaded arrangement (66). [10] Implant (10) according to one of the preceding claims, wherein at least one screw hole (64a, 64b) is provided in the cranial extension (28) and / or in the caudal extension (26), wherein at least one screw hole (64a, 64b) is provided with a threaded arrangement (66) or a ramp arrangement (68). [11] Implant (10) according to one of the preceding claims, wherein a screw hole (64b) is provided in the cranial process (28) and / or a screw hole (64b) is provided in the caudal process (26) with a ramp arrangement (68). [12] Implant (10) according to claim 10 or 11, wherein each ramp arrangement (68) is provided with an inclination (94) extending along an inclination axis (sa), wherein the inclination axis (sa) is directed towards an anatomical center point (p) located at an anatomical point of the center of the circular segment-like cut (42) with which the tibial head (44) is cut, wherein the inclination axis (sa) intersects at this anatomical center point (p). [13] Implant (10) according to claim 11, wherein the inclinations (94) of the ramps (68) are designed such that when a screw (62b) is inserted into the screw hole (64b) with the ramp (68) and tightened, a screw head of the screw (62b) brought into contact by tightening exerts a force (f) with a force direction through the anatomical center (p) or through a central axis (m) directed from medial to lateral through the anatomical center (p). [14] Implant (10) according to one of the preceding claims, wherein in the head section (24) a cranial screw hole (64a), a caudal screw hole (64a) and a proximal screw hole (64a) are provided between the cranial and the caudal screw hole (64a), wherein the axis (a1) of the cranial screw hole forms an angle (γ1) with the sagittal plane (st) in a proximal-distal direction in the range of 97-87° and preferably 92°, wherein the proximal screw hole axis (a3) ​​forms an angle (γ2) with the sagittal plane (st) in the proximal-distal direction in the range of 89-79° and preferably 84°, wherein the caudal screw hole axis (a3) ​​forms an angle (γ3) with the sagittal plane (st) in the proximal-distal direction in the range of 92-82° and preferably 87°. [15] Implant (10) according to one of the preceding claims, wherein a cranial screw hole (64a), a caudal screw hole (64a) and a proximal screw hole (64a) are provided between the cranial and caudal screw holes (64a) in the head section (24), wherein the axis (a1) of the cranial screw hole forms an angle (γ4) with the sagittal plane (st) in a caudal-cranial direction in the range of 91-105° and preferably 96° or 100°, wherein the axis of the proximal screw hole (a2) forms an angle (γ5) with the sagittal plane (st) in a caudal-cranial direction in the range of 88-98° and preferably 93°, wherein the caudal screw hole axis (a3) ​​forms an angle (γ6) with the sagittal plane (st) in a caudal-cranial direction in the range of 82-67° and preferably 77° or 72°. [16] Drill guide (76) for guiding and positioning a drill (78) during drilling on the tibia (20) for fixing the implant (10) according to one of claims 10 to 15 with a non-head-locking screw (62b) through one of the screw holes (64b) provided with a ramp arrangement (68), comprising a bolt (80) with a threaded section (82) and a fastening section (84) for screwing into a screw hole (64a) provided with a thread arrangement (66) located near the screw hole (64b) with ramp arrangement (68), and a drill guide piece (86) with a guide section (88) for a drill (78) attachable to the bolt (80), wherein the drill (78) is guided perpendicular to the screw hole (64b) with the ramp arrangement (68) when the drill guide piece (86) is attached to the Bolt (80) is attached. [17] Modular system with a plurality of implants (10) according to at least one of claims 1 to 15. [18] Modular system according to claim 17, comprising a drill guide (76) according to claim 16.

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