Unit for reaming the surfaces of the articular cartilage and the bone around the joint of the acetabulum and the femoral head

Abstract

The subject of the invention is a unit for reaming the surface of the articular cartilage and the periacetabular bone of the acetabulum and the femoral head during orthopaedic surgery, which is used as a device for preparing the surface of the cartilage and the periacetabular bone for the implantation of an endoprosthesis. The unit is characterized in that it has at least two files (2), the at least two files (2) having an inclined end of a cutting blade (16) and an arcuate shape ending in a spherical pivot (10), the spherical pivot (10) being placed in a guide (11) of a base body 3, while each file (2) is placed in a channel (12) of a shaped body (1), and the body (1) is connected to the drive mechanism (6) of the unit by means of a joint, and the base body (3) is placed on a handle (13), the handle (13) being connected to a shaft (4) by means of a threaded connection (18) having a locking member (8), and the body (1) having a threaded joint (17) connected to the shaft (4).

Description

Technical field

[0001] The subject of the invention is a unit for reaming the surface of the articular cartilage and the periacetabular bone of the acetabulum and the femoral head for use in orthopaedic surgery, which serves as a device for preparing the surface of the cartilage and the periacetabular bone for the implantation of an endoprosthesis. Background art

[0002] Current solutions are based on sets of burrs with graded, fixed diameters, and various devices used during surgery. The disadvantage of these solutions is the large number of elements in the surgical set that are often not used during surgery. The currently used tools do not allow the controlled removal of the cutting products outside the surgical area.

[0003] Units for reaming the inner surface of joints (especially the hip joint) are known and thus: in the US patent description US2006217730, an improved spring-loaded expandable acetabular reamer is described, which includes a certain number of convex reaming segments that are symmetrically paired around the central core of the reamer tool. Another object of the invention is to provide and improve spring-loaded reaming segments that expand faster and require less manipulation by the surgeon and staff, thus minimizing the risk of infection and tissue damage. In addition, introducing a large-sized conventional acetabular reamer with rough and sharp edges through a small surgical incision will undoubtedly cause damage to the incision edge and the surrounding soft tissue, which may ultimately lead to delayed wound healing.

[0004] The US6918914 patent shows an acetabular reamer that includes a reaming head having arcuate segments that are generally symmetrically distributed around a central point. The arcuate segments can extend or retract around the central point to create a recess with a variable size in the acetabular region. The reamer may also include an actuator for selectively extending or retracting the segments such that as the segments expand or retract, the segments remain generally symmetrically distributed around the central point. The segments may also include a cutting surface having a shape corresponding to a portion of a hemispherical surface. In one form, the segments can be configured as narrow symmetric "slices" of a hemispherical surface, which provides an adjustable hemispherical cutting arc, while the US7220264 patent describes a reamer for reaming the acetabulum during minimally invasive surgery. Generally, the reamer (especially the reamer head) can be inserted and removed through a relatively small incision without traumatizing the tissue around the incision. The reamer generally includes a reaming or scraping portion that is substantially aligned along a single meridian of the hemisphere. The reamer also includes a stabilizing portion to help ensure a selected reaming orientation.

[0005] In the US2006264958 / US7608076 patent, the use of a surgical reamer for cutting cartilage and bone tissue is shown. The reamer also includes: a fixed support portion aligned with the drive axis and having at least one radially cutting blade; a pivot portion aligned with the drive axis and pivotable about the axis, the pivot portion supporting at least one radially cutting blade; and a pivot joint, wherein the pivot portion is pivotable towards and away from the fixed portion so as to expand or contract the reamer in corresponding overall dimensions.

[0006] In the US2005203525(A1) patent, an acetabular reamer is described which has a cutting structure rotatable about a longitudinal axis and has a domed housing portion. The housing has an outer surface presenting a plurality of cutting sites and an inner surface for accumulating debris. The tool shape is defined by a pair of first curved portions and a pair of second curved portions, the pair of first curved portions being generated about a first radius and having a center located on the axis, the pair of second curved portions being generated about a center spaced from the axis.

[0007] In the US2006276797(A1) patent, an expanding reamer for reaming or cutting a concave surface is discussed, for example, for reaming the acetabulum to prepare for implanting a prosthetic member (such as an acetabular cup or socket) during hip arthroplasty. The reamer includes a rotating shaft cooperating with a surgical drill or other power source at one end and rotating a reamer head at the other end, and a system adapted to expand one or more blades on the reamer head. In a preferred embodiment, the reamer head includes a plurality of generally circular (preferably substantially flat and parallel) blades, the outer blades of which can expand radially as segments of a cutting sphere to increase the effective diameter of the reamer head. The US2007016211(A1) patent discusses an expanding reamer for reaming or cutting a concave surface, for example, for reaming the acetabulum to prepare for implanting a prosthetic member during hip replacement. The rotating shaft cooperates with a surgical drill or other power source at one end and rotates a reamer head at the other end, and an actuation system expands one or more blades on the reamer head. The reamer head includes one or more cutting blades which act as segments of a cutting sphere, wherein the blades can expand in a direction not parallel to the plane of the respective blade so as to increase the cutting sphere. When the reamer head rotates, the (s) blades form part of an effective cutting sphere which is preferably greater than 180 degrees; this allows for greater flexibility in the placement of the axis of the reamer relative to the surface being reamed (e.g., relative to the axis center of the acetabulum). In the US2011202060(A1) patent, a disposable acetabular reamer is described which is designed to improve tissue removal efficiency. The reamer device includes a reamer cutting housing and a reamer driver interface. The reamer cutting housing has a hemispherical structure having a plurality of spaced ribs which extend from a central region near the apex of the housing. Summary of the Invention

[0008] The essence of the invention is a unit for reaming the articular cartilage and the surface of the bone around the joint of the acetabulum and the femoral head, characterized in that the unit has at least two rasps, the at least two rasps having an inclined end of the cutting blade and an arcuate shape ending in a spherical pivot, the spherical pivot being placed in a guide of the base body, and each rasp being placed in a channel of a shaped body, and the body being connected to the drive mechanism of the unit by means of a joint, and the base body being placed on a handle, the handle being connected to a shaft by means of a threaded connection having a stop, and the body having a threaded joint connected to the shaft.

[0009] It is advantageous in the following cases: the body has a chamber for fixing the reamed bone, and the body has an external support surface for insertion into the acetabulum of the reamed bone and for protecting the bone tissue from damage.

[0010] It is also advantageous in the following cases: each rasp is placed at the same angular distance from a circular plane perpendicular to its longitudinal axis, and the rasp is beveled at an angle β of 40 - 50°, advantageously at 45°.

[0011] It is also advantageous in the following cases: the application angle α of the rasp blade relative to the surface being reamed is in the range of 5 - 15°, advantageously 10°.

[0012] It is particularly advantageous in the following cases: the cutting edge of the rasp has a cutting tongue.

[0013] Furthermore, it is advantageous in the following cases: the rasp is a tubular body or an open element or a partially open element.

[0014] It is advantageous in the following cases: each rasp has an outlet opening of a conduit for cleaning the inside of the rasp.

[0015] The use of the solution proposed in the invention achieves the following technical and practical effects:

[0016] • The possibility of precisely machining the acetabular surface without complete resection, similar to the case of traditional solutions,

[0017] • Reduction of the invasiveness of the surgery,

[0018] • The possibility of using a customized intra-articular prosthesis,

[0019] • The geometry, position and movement of the cutting blade enable the removal of chips outside the surgical area, which ensures a higher sterility and visibility of the area where the surgery is performed,

[0020] • The possibility of obtaining a continuously variable cutting diameter adapted to the diameter of the machined acetabulum,

[0021] • Obtain high machining accuracy,

[0022] • Obtain high surface finish of the machined surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In a non - limiting exemplary embodiment, the subject matter of the present invention is presented in the drawings, in which: Figure 1 A cross - section of the unit for machining the femoral head in the first solution in a plane passing through its axis of rotation is presented, Figure 2 A cross - section of the body of the unit for machining the femoral head in the first solution in a plane passing through its axis of rotation is presented, Figure 3 A cross - section of the unit for machining the acetabulum in the second solution in a plane passing through its axis of rotation is presented, Figure 4 A cross - section of the unit for machining the acetabulum in the second solution in a plane passing through its axis of rotation is presented, Figure 5 A view of the base body is presented, Figure 6 A cross - section of the base body in a plane perpendicular to its longitudinal axis is presented, Figure 7 A view of the base body in a plane passing through its longitudinal axis is presented, Figure 8 A view of the shaft is presented, Figure 9 A partial cross - section is presented, which passes through the base body in a plane passing through the axis of the channel, and the channel carries a blade, Figure 10 A view of the blade partially opened is presented, Figure 11 A view of detail A from Figure 10 is presented, while Figure 12 A placement of the file blade against the machined surface is presented. DETAILED DESCRIPTION

[0024] The unit for machining the outer surface of the joint bone (i.e., the head) has at least two files 2, the at least two files 2 having an inclined end with a cutting blade 16 and an arcuate shape ending in a spherical pivot 10, the spherical pivot 10 being placed in a guide 11 of a base 3. Each file 2 is placed in a channel 12 of a shaped body 1. The body 1 is connected to a drive mechanism 6 of the unit by a joint, while the base 3 is placed on a handle 13 which has a threaded connection 18 with a stop 8 connected to a shaft 4, and the body 1 has a threaded joint 17 connected to the shaft 4. Each file 2 is placed at the same angular distance from a circular plane perpendicular to its longitudinal axis. The files 2 are beveled at an angle β of 45°, and the application angle α of the cutting blade 16 of the files 2 to the machining surface 26 has a value of 10°. The cutting blade 16 of the files 2 has a cutting tongue 19 for breaking up the cutting substance. There is a variant where the files 2 are tubular bodies, there is a variant where the files 2 are open elements, and there is a variant where the files 2 are partially open elements. Each file 2 in the first variant has an outlet opening 23 of a file duct 24 for cleaning the inside of the file 2.

[0025] The drive mechanism 6 is permanently connected to the base 3 by a shaft 4 that transmits rotational drive. The base 3 moves in a reciprocating and rotational manner by a threaded connection 14 to the shaft 4. In the base 3, the files 2 with cutting blades 16 move within ducts 12 of the body 1. Each file 2 moves through a duct 12 which forces it to move only on a specific trajectory. The cutting blade 16 of the files 2 is connected to the base 3 by a movable connection using a spherical pivot 10 and a guide 11, the spherical pivot 10 and the guide 11 ensuring a minimum movement of the cutting blade 16 of the files 2 relative to the base 3 and the body 1.

[0026] The drive mechanism 6 is connected to an external rotary drive. By connecting the drive mechanism 6 to the shaft 4, the rotational movement is transmitted to the entire tool. During operation, the tool rotates about the axis of the shaft 4 - the specified axis of symmetry of the tool. Depending on the angular setting of the cutting blade 16, the movement is clockwise or counterclockwise. The shaft 4 is connected to the body 1 by a threaded connection 18. Both the connection to the body 1 and the drive mechanism 6 have threads that are consistent with the rotational direction of the tool, which prevents possible part disconnection. The base 3 is screwed onto the shaft 4 and it moves on a thread with a high pitch, which ensures a high linear displacement and a low angular displacement. The movement of the base 3 is locked by a stopper 8 - wedge 9 system. After setting the size of the cutting area 25 of the joint by turning the base 3 about the axis of symmetry of the tool using the widened part of the shaft 4 with a notch for easy gripping, the movement of the base 3 is locked by screwing the stopper 8 into the threaded hole 15 located in the base 3. Screwing in the stopper 8 causes the bottom surface of the wedge 9 to be gradually driven into the non-threaded surface of the shaft 4. At a certain point, it becomes impossible to screw in the stopper 8 gradually, which means that the wedge 9 bearing against the surface of the shaft 4 has completely locked the movement of the stopper 8 - base 3 system. To release the movement of the base 3, the stopper 8 should be unscrewed from the base 3. The base 3 moves within the chamber of the body 1, which is limited by two parts of the wall of the body 1 and the cover 5 of the body 1. The cover 5 of the body 1 limits the maximum protrusion of the base 3 and additionally stabilizes the position of the base 3 relative to the axis of symmetry of the tool. The cover 5 of the body 1 is bolted to the body 1 using a set of four mounting bolts 7. The rotational and linear movement of the base 3 relative to the shaft 4 causes the head of the base 3 to press against the spherical end of the cutting blade 16 of the file 2. The end of the cutting blade 16 of the file 2 in the shape of a spherical pivot 10, which is set on a threaded rod and screwed into the body 1, moves within the channel 12 cut in the surface of the head of the base 3. The guide 11 is cut symmetrically or asymmetrically relative to the axis of rotation of the tool - depending on the number of cutting blades 16, etc. The guide 11 limits the movement of the cutting blade 16. Unscrewing the base 3 from the body 1 relative to the shaft 4 causes the cutting blade 16 of the file 2 to slide into the closed chamber of the body 1 at an angle of 45°. Screwing in the base 3 has the opposite effect. The cutting blade 16 of the file 2 slides out, causing the cutting edges to be closer to each other, which results in a decrease in the final diameter of the machined spherical surface. The movement of the cutting blade 16 of the file 2 outside the guide 11 cut in the head of the base 3 occurs within the space limited by the opening 15 in the body 1. The channel 12 ensures the movement of the cutting blade 16 of the file 2 on an arc-shaped trajectory with a defined radius. After determining the appropriate diameter for machining - i.e., the position of the cutting blade 16 of the file 2 and locking the movement of the base 3 using the stopper 8 - the drive mechanism 6 is used to provide the rotational movement from the external drive. The application angle α of the cutting blade 16 of the base 3 has a value of 10°, and the attack angle β has a value of 45°.The chips fall into the conduit 24 of the file 2 and thus fall out through the outlet opening 23 of the conduit 24 for cleaning the interior of the file 2 between the inner chamber 21 and the outer chamber 22 of the body 1. A conduit for a medium 20 (such as water) passes along the shaft 4 through the drive mechanism 6, which enables the medium to be delivered to the interior space of the body 1, thereby diluting the chips and assisting in removing said chips.

[0027] After determining the position (cutting diameter) of the base body 3, the base body 3 is locked using the wedge 9 by screwing in the stop 8, and then the drive is started. Thereafter, the tool is applied to the machined surface, such as the hip joint, and the medium is supplied through the conduit 20 in the drive mechanism 6 by positioning along the shaft 4, and then the surface is cut using the cutting blade 16 of the file 2. The chips and the medium fall out through the outlet opening 23 of the file conduit 24. Larger chips are broken by the cutting tongue 19. After removing a specified amount of material from the hip joint, the position of the base body 3 is corrected by unlocking the clamp of the drive mechanism 6. After making the change, the machined surface (such as the hip joint after removing another layer of hip joint tissue) is inspected, the base body 3 is locked again and the material is removed again until the desired hip joint surface is obtained. The cutting area is limited by the outer edge of the tool.

[0028] The unit for machining the outer surface of a joint bone (i.e., the acetabulum) has at least two files 2, the at least two files 2 having an inclined end of the cutting blade 16 and an arcuate shape ending in a spherical pivot 10, the spherical pivot 10 being placed in the guide 11 of the base body 3. Each file 2 is placed in a channel 12 of the shaped body 1. The body 1 is connected to the drive mechanism 6 of the unit by a joint, while the base body 3 is placed on a shank 13, which shank 13 has a threaded connection 18 with a stop 8 connected to the shaft 4, and the body 1 has a threaded joint 17 connected to the shaft 4. Each file 2 is placed at the same angular distance from a circular plane perpendicular to its longitudinal axis. The files 2 are chamfered at an angle β of 45°, and the application angle α of the cutting blade 16 of the file 2 with respect to the machined surface 26 has a value of 10°. The cutting blade 16 of the file 2 has a cutting tongue 19 for breaking the cut material. There is a solution where the file 2 is a tubular body, there is also a solution where the file 2 is an open element, and there is also a solution where the file 2 is a partially open element. Each file 2 in the first solution has an outlet opening 23 of the file conduit 24 for cleaning the interior of the file 2.

[0029] The drive mechanism 6 is permanently connected to the base body 3 via a shaft 4 that transmits rotational drive. The base body 3 moves in a reciprocating and rotational manner by means of a threaded connection 14 with the shaft 4. In the base body 3, a file 2 with a cutting blade 16 moves within a channel 12 of the body 1. Each file 2 moves through the channel 12, which forces it to move only along a specific trajectory. The cutting blade 16 of the file 2 is connected to the base body 3 using a movable connection via a spherical pivot 10 and a guide 11, which ensures their minimal movement relative to the base body 3 and the body 1.

[0030] The drive mechanism 6 is connected to an external rotary drive. By connecting the drive mechanism 6 to the shaft 4, the rotational movement is transmitted to the entire tool. During operation, the tool rotates about the axis of the shaft 4 - the specified axis of symmetry of the tool. Depending on the angular setting of the cutting blade 16, the movement is clockwise or counterclockwise. The shaft 4 is connected to the body 1 by a threaded connection 18. The connections to both the body 1 and the drive mechanism 6 have threads that are consistent with the rotational direction of the tool, which prevents possible disconnection of parts. The base 3 is screwed onto the shaft 4 and it moves on a thread with a high pitch, which ensures a high linear displacement and a low angular displacement. The movement of the base 3 is locked by a stopper 8 - a wedge 9 system. After setting the dimensions of the cutting area 25 of the joint by rotating the base 3 about the axis of symmetry of the tool using the widened part of the shaft 4 with a notch for easy gripping, the movement of the base 3 is locked by screwing the stopper 8 into the threaded hole 15 located in the base 3. Screwing in the stopper 8 causes the bottom surface of the wedge 9 to gradually drive into the non-threaded surface of the shaft 4. At a certain point, it becomes impossible to gradually screw in the stopper 8, which means that the wedge 9 bearing against the surface of the shaft 4 has completely locked the movement of the system of the stopper 8 and the base 3. To release the movement of the base 3, the stopper 8 should be unscrewed from the base 3. The base 3 moves within the chamber of the body 1, which is limited by two parts of the wall of the body 1 and the cover 5 of the body 1. The cover 5 of the body 1 limits the maximum protrusion of the base 3 and additionally stabilizes the position of the base 3 relative to the axis of symmetry of the tool. The cover 5 of the body 1 is bolted to the body 1 using a set of four mounting bolts 7. The rotational and linear movement of the base 3 relative to the shaft 4 causes the head of the base 3 to press against the spherical end of the cutting blade 16 of the file 2. The end of the cutting blade 16 of the file 2 in the shape of a spherical pivot 10, which is set on a threaded rod and screwed into the body 1, moves within the channel 12 cut in the surface of the head of the base 3. The guide 11 is cut symmetrically or asymmetrically relative to the axis of rotation of the tool - depending on the number of cutting blades 16, etc. The guide 11 limits the movement of the cutting blade 16. Unscrewing the base 3 from the body 1 relative to the shaft 4 causes the cutting blade 16 of the file 2 to slide into the closed chamber of the body 1 at an angle of 45°. Screwing in the base 3 has the opposite effect. The cutting blade 16 of the file 2 slides out, causing the cutting blades 16 to be closer to each other, which results in a decrease in the final diameter of the machined spherical surface 26. The movement of the cutting blade 16 of the file 2 outside the guide 11 cut in the head of the base 3 occurs within the space limited by the opening 15 in the body 1. The channel 12 ensures the movement of the cutting blade 16 of the file 2 on an arc-shaped trajectory with a defined radius. After determining the appropriate diameter for machining - i.e., the position of the cutting blade 16 of the file 2 and locking the movement of the base 3 using the stopper 8 - the drive mechanism 6 is used to provide rotational movement from an external drive. The cutting edge 16 of the file 2 penetrates the material to the set diameter.The application angle α of the cutting surface 25 of the cutting insert 16 of the substrate 3 has a value of 10°, and the chamfer angle β has a value of 45°. The chips fall into the conduit 24 of the file and thus exit through the outlet opening 23 for cleaning the interior of the file between the inner chamber 21 of the body 1 and the support surface 27. A conduit for the medium 20 (such as water) passes along the axis 4 through the drive mechanism 6, which enables the delivery of the medium into the interior space of the body 1, thereby diluting the chips and assisting in removing said chips.

[0031] After determining the position (cutting diameter) of the substrate 3, the substrate 3 is locked using the wedge 9 by screwing in the stopper 8 and then driving is started. Thereafter, the tool is applied to the machined surface, such as the hip joint, and the medium is supplied through the conduit 20 in the drive mechanism 6 by positioning along the axis 4, and then the surface is cut using the cutting insert 16 of the file 2. The chips and the medium exit through the outlet opening 23 of the file conduit 24. Larger pieces of chips are broken by the cutting tongue 19. After removing a specified amount of material from the hip joint, the position of the substrate 3 is corrected by unlocking the clamp of the drive mechanism 6. After making the change, the machined surface (such as the hip joint after removing another layer of hip joint tissue) is inspected, the substrate 3 is locked again and the material is removed again until the desired hip joint surface is obtained. The cutting area is limited externally by the cutting edge of the tool and internally by the support surface 27, thereby protecting the cortical tissue from damage during the cutting process. No cutting process is performed in the area of the support surface 27.

Claims

1. A unit for reaming the surfaces of the articular cartilage and the bone around the joint of the acetabulum and the femoral head, wherein, The unit has at least two rasps (2), the at least two rasps (2) having an inclined end of a cutting blade (16) and an arcuate shape ending in a spherical pivot (10), the spherical pivot (10) being placed in a guide (11) of a base body (3), wherein each rasp (2) is placed in a channel (12) of a shaped body (1), wherein the body (1) is connected to a drive mechanism (6) of the unit by a joint, wherein the base body (3) is placed on a handle (13), the handle (13) being connected to a shaft (4) by a threaded connection (18) having a locking member (8), and the body (1) having a threaded joint (17) connected to the shaft (4), wherein each rasp (2) has an outlet opening (23) of a conduit (24) for cleaning the interior of the rasp (2).

2. The unit according to claim 1, characterized in that, The body (1) has a chamber (22) for placing the head of a machined bone.

3. The unit according to claim 1, characterized in that, The body (1) has an external support surface (27) configured to be inserted into the acetabulum of a reamed bone and to protect the bone tissue from damage.

4. The unit according to claim 1, wherein Each rasp (2) is placed at the same angular distance from a plane perpendicular to the longitudinal axis of the unit.

5. The unit according to claim 1, characterized in that, Each rasp (2) is chamfered at an angle of 40 - 50°.

6. The unit according to claim 5, characterized in that, Each rasp (2) is chamfered at an angle of 45°.

7. The unit according to claim 1, wherein The application angle of each rasp (2) with respect to the reamed surface is in the range of 5 - 15°.

8. The unit according to claim 7, characterized in that, The application angle of each rasp (2) with respect to the reamed surface is 10°.

9. The unit according to claim 1, characterized in that, The cutting edge of each rasp (2) has a cutting tongue (19).

10. The unit according to claim 1, characterized in that, Each rasp (2) is a tubular body.

11. The unit according to claim 1, characterized in that Each rasp (2) is an open element.

12. The unit according to claim 1, wherein Each rasp (2) is a partially open element.

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