Improved milling cutter for orthopedic surgery, especially for knee, pelvis or ankle surgery

Abstract

The present invention relates to an orthopedic surgical instrument, in particular a milling cutter, comprising an inner rod (2) extending along its longitudinal axis (XX) and having an attachment end (7) for a motorized member, a tubular envelope (5) enclosing the inner rod (2), an operating head (15) at a rod end (8) opposite the attachment end (7), and a horizontal universal joint (10) between the rod end (8) of the operating head and a tool (9) so that the tool (9) extends along an axis (YY) angled relative to the longitudinal axis (XX). The milling cutter according to the present invention improves the precision of hole placement in surgical procedures involving difficult-to-access anatomies, such as the knee, pelvis, and ankle.

Description

[Technical Field]

[0001] The present invention refers to orthopedic surgical instruments, and more particularly to improved milling cutters that can be used in knee, pelvic or ankle surgery, and references to these specific applications are made to simplify the description but should not represent a limitation of the applicant's rights.

[0002] More specifically, the present invention refers to an instrument for performing incisions or milling on the human tibia in preparation for other surgical steps performed on portions of the tibia where access is very limited. However, the disclosed instrument can be used in other types of surgical procedures, such as, for example, surgery on the acetabular cup of the pelvis or procedures on the ankle. [Background technology]

[0003] It is known that aging, disease or sporting activities can cause the knee joint surfaces to deteriorate and lead to pathology.

[0004] Similarly, other bones may become deformed over time or develop pathologies that must be treated surgically with appropriate instruments.

[0005] For example, in the case of the knee, it has become common to perform surgery by removing the condyles and replacing these bony structures with prosthetic implants, and the articular surface of the patella can be replaced, taking great care not to contact or cut the tendons connected to the patella.

[0006] A relatively common operation, with several surgical strategies in this branch of technology, is the replacement of the posterior or medial side of the patella adjacent to the femoral condyle by the implantation of a prosthetic device. For this purpose, the posterior surface of the patella is resected to create a flat surface onto which the prosthesis can be attached.

[0007] FIG. 1 shows a schematic side view of a single compartment surgical procedure, e.g., milling, in which the distal portion of the femur and the proximal portion of the tibia, relevant to knee articulation, can be seen.

[0008] The drawings show schematically the locations of the femur and tibia that can typically be reached during a single compartment procedure, and it can be seen that the femur covers a portion of the tibia, making access particularly difficult. Essentially, the incision area is much smaller than the area available for the entire prosthetic procedure.

[0009] Furthermore, although the ligaments and soft tissues are generally in good condition, this means that the femur cannot be moved as much, and certainly not as much as in the entire prosthetic procedure, due to the retention of both the (anterior and posterior) cruciate ligaments and the patella not being displaced.

[0010] All this, specifically due to the proximity of the distal part of the femur, preparation of the proximal part of the tibia cannot be performed for the reasons mentioned above, but must be performed in the front-superior mode, i.e., in a position that is not comfortable for positioning the instruments.

[0011] For example, preparation of the tibia for implantation of stabilizing elements such as unicompartmental plates, pins, etc. is typically performed with the tip of a milling cutter positioned in an oblique orientation, which involves the removal of larger amounts of bone that is filled with bone cement.

[0012] Figure 2 shows a schematic diagram illustrating this situation, where a 9 mm milling cutter tip is used to create a seat for the stabilizing element that is only 6.2 mm in diameter.

[0013] This solution has two obvious drawbacks: Increased removal of bone tissue; The cement's airtightness is surprisingly poor, since it is optimal when the thickness around the pin is limited to about 1 mm. On the contrary, the cement distribution is not uniform, and adhesion is poor at thicknesses ranging from 0.5 mm to 2.5 mm.

[0014] For example, as described in EP 1 410 763 or EP 2 954 860, the tip of a milling cutter is attached to one end of a surgical instrument. Universal joint There are technical solutions that allow the working axis of the milling cutter to be angled, but these solutions are structurally complex and are not suitable for knee surgery.

[0015] The object of the present invention is to devise an orthopaedic surgical instrument, in particular an improved milling cutter, having structural and functional properties such as those that overcome the reported drawbacks of prior art solutions.

[0016] Another object of the invention is to devise an instrument that allows the preparation of the operating table above the knee in an axis with anterior access in order to avoid interference with the distal part of the femur.

[0017] A further object of the present invention is to prevent the surgeon from relying solely on his manual and visual abilities to handle the instrument, but to allow him to operate it in a comfortable and practical way, taking advantage of the configuration of the instrument itself.

[0018] It is yet another object of the present invention to provide an instrument that is easy to handle and use by an orthopedic surgeon and that does not obstruct the surgeon's view during surgery.

[0019] Finally, the device of the present invention must be easy to disassemble and reassemble to ensure cleaning, sanitization, and reuse of the device. Summary of the Invention

[0020] The solution underlying the present invention is to devise a milling cutter that has an operating head that is angled relative to the longitudinal axis of the instrument, but that has a particularly simple and functional overall structure.

[0021] The above listed objects are achieved by an orthopaedic surgical instrument, and more particularly by an improved milling cutter, the orthopaedic surgical instrument comprising: an inner rod extending along its longitudinal axis (XX) and having an end for attachment to an electrically powered member; a tubular envelope encasing the inner rod; an operating head at the rod end opposite the mounting end; Between the rod end of the operating head and the tool Universal joint whereby the tool extends along an axis (YY) angled relative to the longitudinal axis (XX), Universal joint And, it is equipped with.

[0022] Preferably, the tubular envelope is made up of two overlapping half shells covered by a handle.

[0023] Furthermore, the inner rod is idle relative to the tubular envelope so that it can be rotated under the action of the powered member while the surgeon holds the instrument.

[0024] At least one pair of bushings are provided mounted in an idle manner on opposite portions of the inner rod for supporting the tubular envelope.

[0025] The bushing is made of a low friction synthetic material, such as PEEK.

[0026] Furthermore, the end of one of the two half shells is connected to the operating head. Universal joint Such a receiving seat has an annular portion having an axis corresponding to the angular axis (YY) mentioned above.

[0027] An optional anti-rotation element, for example an anti-rotation protruding notch, is provided on at least one of the two half shells to hold a handle that encases both half shells of the tubular envelope.

[0028] lastly, Universal joint It should be noted that the has one part that corresponds to the rod end of the operating head and another part, e.g., a tip for drilling or milling.

[0029] Selected embodiments will now be described in detail with reference to the drawings. From this disclosure, it will be apparent to those skilled in the art of orthopedic surgery that the following description of preferred embodiments is provided for purposes of illustration only and not for purposes of limiting the invention, which is defined by the appended claims. [Brief explanation of the drawings]

[0030] [Figure 1] 1A-1C show schematic partial and lateral views of articulation during orthopaedic surgery using orthopaedic surgical instruments made according to the prior art. [Figure 2] 2 shows a side and partial schematic view of the working end of the orthopaedic surgical instrument of FIG. 1 in more detail, always according to the prior art; [Figure 3] 1 shows a prospective schematic of an orthopedic surgical instrument made in accordance with the present invention. [Figure 4] 3 shows another possible schematic diagram of the device of FIG. 2, showing its major components. [Figure 5] 4 shows a schematic side view of the components of the device of FIG. 3. [Figure 6] 4 shows a schematic side view of another component of the device of FIG. 3. [Figure 7] 7 shows a schematic side cross-sectional view of part of the component of FIG. 6 on a vertical plane. [Figure 8] 1 shows a prospective schematic view of an orthopaedic surgical instrument of the present invention in an assembled state. [Figure 9] 1 shows a schematic partial and lateral view of articulation associated with an orthopaedic surgical procedure using an orthopaedic surgical instrument made in accordance with the present invention. [Figure 10] 1 shows a schematic side view of another example embodiment of a device according to the invention, in particular for use in the hip joint region; [Figure 11] 11 shows a schematic side cross-sectional view of the device of FIG. 10 taken along line AA. [Figure 12] 1 shows a schematic cross-sectional view on a vertical plane of an example of the application of the instrument according to the invention in a surgical procedure for articulation of the ankle. [Figure 13] 1 shows a schematic cross-sectional view on a vertical plane of an example of the application of the instrument according to the invention in a surgical procedure for articulation of the ankle. DETAILED DESCRIPTION OF THE INVENTION

[0031] With reference to the accompanying drawings, an improved milling cutter that can be used in orthopedic surgery, and more particularly in knee, pelvis, and ankle surgery, is generally and generally designated 1. The following description will be made with reference to these particular fields of application, which is intended solely to simplify the description and does not represent a limitation on the applicant's rights.

[0032] The milling cutter 1 comprises an elongated body having an inner rod 2 covered by a tubular, preferably cylindrical, envelope 5 formed by first and second half shells 3, 6, and a handle 4 enclosing most of the tubular envelope 5.

[0033] The two half shells 3 , 6 are connected to each other as two shells to form a tubular envelope 5 .

[0034] The handle 4 overlaps the tubular body 5 over at least two-thirds of its extension.

[0035] The inner rod 2 extends along a main and longitudinal axis XX and has an end 7 shaped and configured as a quick coupling attachment for a powered member, for example the spindle of a drill (not shown).

[0036] The opposite end 8 of the rod 2 is kinematically connected and articulated to an operating head 15 of a milling cutter 1 which carries, for example, a drilling tool tip 9 .

[0037] Advantageously, the inner rod 2 is idle relative to the tubular envelope 5 and the handle 4. In other words, the rod 2 can be rotated by coupling with a motorized member while the orthopedic handle is held firmly in the surgeon's hand.

[0038] At least one pair of bushings 11, 12 are provided and attached to both ends of the inner rod 2 to allow the juxtaposition and attachment of the half shells 3 and 6 to form a tubular envelope 5 which is later covered by the handle 4.

[0039] The first bushing 11, defined as proximal, is located at the shaped end 7 and is freely movable along the rod 2 up to a predetermined distance from the end 7 defined by a spacer 13.

[0040] The other bushing 12 , defined as the distal one, is always located on the same rod 2 near the end 8 connected to the operating head 15 .

[0041] The bushings are allowed to slide freely along the rod 2 until the envelope 5 consists of two half shells 3, 6, at which point they are received in respective molded seats 20, 21 of the envelope 5.

[0042] In a preferred but not exclusive embodiment, the two proximal and distal bushings 11 and 12 are made of a synthetic material, for example PEEK, to reduce the friction of the rotation of the rod 2 and to ensure the correct functioning of the cutter.

[0043] All of the above-mentioned parts that make up the milling cutter 1 are easily detachable and separable from one another to facilitate their cleaning.

[0044] Advantageously, according to the invention, there is provided between the rod end 8 of the operating head 15 and the tool 9, such that the tool 9 can extend along an axis YY which is angled relative to the longitudinal axis XX of the milling cutter 1. Universal joint 10 is provided.

[0045] Furthermore, the operating head 15 Universal joint A receiving seat 18 is provided for receiving the 10.

[0046] This receiving seat 18 is substantially oriented so that the axis YY of the tool tip 9 is oriented in a predetermined angular range "α" relative to the extension axis XX of the rod 2 of the milling cutter 1. Universal joint 10, for example, the angled body of the open guide capsule that houses the joint.

[0047] This receiving seat 18 is integrally formed at the distal end of only one of the two half shells 3, 6 of the tubular envelope 5 encasing the rod 2. More specifically: Universal joint A receiving seat 18 for accommodating 10 is obtained at the end of the half shell 6, as also shown in FIGS.

[0048] The receiving seat 18 has an axis corresponding to the angled axis YY and has an annular portion 19 which corresponds to a guide for the angular orientation of the tool tip 9. Such annular portion has a diameter slightly larger than that of the tool tip 9.

[0049] This possible displacement of the single half-shell therefore makes it possible to change the inclination of the angle “α” between the axis XX of the two rods 2 and the orientation of the YY of the tool tip 9 .

[0050] Always at the distal end of such half-shell 6, integral with the receiving seat 18, a shield appendage 17 and the final configuration of the distal end of the tubular envelope 5 are obtained.

[0051] The other half-shell 3 has a distal end 16 which is partly pointed and conforms to an appendage 17 of the other half-shell.

[0052] At least one of the half shells 3, 6 is also provided with an anti-rotation element, for example an outwardly projecting notch 14, in order to perform an anti-rotation function and to hold the handle 4 in place once the handle 4 enveloping the half shells 3, 6 of the tubular envelope 5 is attached. The notch 14 is preferably obtained on the half shell 6 which also has an integrally formed receiving seat 18, intended to be inserted into a corresponding slot on the inside of the handle 4.

[0053] Each half shell 3,6 is provided with a recess 20,21 for receiving the associated bushing portion 11 or 12.

[0054] Finally, the rod 2 and the tip 9 are connected. Universal joint It will be noted that tool tip 10 has a portion corresponding to end 8 of rod 2 and another portion connected to said tool 9. The portion associated with end 8 of rod 2 may be integrally formed with such end, while the other portion may have a thread or quick attachment for removable attachment of tool tip 9.

[0055] The milling cutter 1 according to the invention achieves its predetermined objectives and obtains various advantages, one of which is given by the fact that it allows the processing of holes whose tip axis is inclined at a certain angle relative to the transmission axis of the power rod 2.

[0056] This tool tip angle "α" is particularly advantageous in the operating room to facilitate access to the surgical area and avoid contact of the instrument with the anatomical area.

[0057] The milling cutter according to the present invention improves the accuracy of hole location in surgical procedures involving anatomy that is difficult to access and may or may not be used with the guide instrument 21 seen, for example, in FIG. 9.

[0058] The angled body of the receiving seat 18 determines the angle of inclination between the tip 9 and the axis XX of the rod 2. This angle "α" can be changed by substituting the component 18, i.e. by substituting all half shells 6 of the envelope 5 that form the component 18.

[0059] To use the milling cutter 1 according to the invention, it is sufficient to attach the end 7 of the angled milling cutter 1 to an electric element, for example the spindle of a drill.

[0060] The surgeon can firmly hold the handle on the drill and the handle 4 of the angled milling cutter 1. The hole can be made with or without a guide element.

[0061] 10 and 11, there is shown a further example embodiment of an instrument according to the present invention, configured for surgery in the hip region, particularly for drilling holes for bone screws. Such screws often have an angled access method created by the surgeon requiring angled or flexible instruments to achieve the desired orientation for the screw.

[0062] The device of Figures 10 and 11 is designated by the numeral 1', and in relation thereto cooperating parts having the same structure and function as in the previous embodiment and in detail are designated by the same reference numerals.

[0063] The cup or test cup connected to the instrument that is the object of the invention is shown in the figures. The arrangement of the holes 26 in the cup 25 is such as to make access particularly difficult. It allows tilting of the tip 9 along an axis YY that is angled with respect to the axis XX of the instrument 1'. Universal jointThanks to the tool 1 ′ equipped with 10 it is possible to reach and place the tips 9 in all the holes of the cup 25 .

[0064] 12 and 13 show further examples of application of the instrument 1 of the invention for surgery on the ankle joint, in particular on the distal part of the tibia, and on the talus, respectively.

[0065] Also in these cases, as in the example of FIG. 11, a specific guide element 27 is used to drill a hole with a milling cutter 1 which is used for the subsequent insertion of a bone pin.

[0066] From the drawings it is clear how the configuration of the angled milling cutter 1 allows easier access to the area to be milled, significantly reducing the time required for preparation for surgery or a subsequent orthopedic surgery.

[0067] In understanding the scope of the present invention, the term "comprising" and its derivatives as used herein are intended as open-ended terms that specify the presence of specified features, elements, components, groups, integers, and / or steps, but do not exclude the presence of other unspecified features, elements, components, groups, integers, and / or steps. This also applies to words with similar meanings, such as the terms "including" and "having" and their derivatives. Furthermore, the terms "part," "section," "portion," "member," or "element," when used in the singular, can have the dual meaning of a single part or multiple parts, unless specifically stated otherwise.

[0068] The terms "first" and "second" or "half" may be used herein to describe various components, but it is understood that these components should not be limited by these terms. These terms are used only to distinguish one component from another.

[0069] While only selected embodiments have been chosen to illustrate the invention, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made herein without departing from the scope of the invention as defined in the appended claims.

Claims

1. 1. An orthopedic surgical instrument comprising: an inner rod (2) extending along its longitudinal axis (X-X) and having an end (7) for attachment to an electrically powered member; a tubular envelope (5) enclosing said inner rod (2); an operating head (15) at the rod end (8) opposite said mounting end (7); a universal joint (10) of the operating head (15) between the rod end (8) and a tool (9), whereby the tool (9) extends along an axis (Y-Y) angled relative to the longitudinal axis (X-X); The tubular envelope (5) is made up of two overlapping half shells (3, 6) covered by a handle (4), at least one of the half shells (6) having an anti-rotation element for holding the handle (4) encasing both half shells (3, 6), An orthopedic surgical instrument, wherein the anti-rotation element is an anti-rotation protruding notch (14) for holding the handle (4) encasing both half shells (3, 6) of the tubular envelope (5).

2. 2. An orthopaedic surgical instrument according to claim 1, wherein the inner rod (2) is free-wheeling relative to the tubular envelope (5).

3. 2. An orthopaedic surgical instrument according to claim 1, comprising at least one pair of bushings (11, 12) attached in an idle manner to opposite ends of the inner rod (2) for supporting the tubular envelope (5).

4. An orthopaedic surgical instrument according to claim 3, wherein the bushings (11, 12) are made of synthetic material.

5. 2. The orthopedic surgical instrument according to claim 1, wherein the tubular envelope (5) is made up of two half shells (3, 6), one of which (6) is provided at one end with a receiving seat (18) for accommodating the universal joint (10) of the operating head (15).

6. The orthopaedic surgical instrument of claim 5, wherein the receiving seat (18) has an annular portion (19) having an axis corresponding to the angled axis (Y-Y).

7. The orthopaedic surgical instrument of claim 1 , wherein the universal joint (10) has one portion corresponding to the rod end (8) and another portion removably connected to the tool (9).

8. 2. An orthopaedic surgical instrument according to claim 1, wherein the mounting end (7) is shaped as a quick coupling attachment for the spindle of the powered member.

Images