Abstract: The invention concerns a surgical implant (1) for correcting the mutual positioning or orientation of the bones of a patient designed to be inserted between at least two bone bodies (2, 3) of said patient, and comprising: a main body (5) extending along a longitudinal axis (X-X?), a plurality of fins (9), each fin (9) being provided with a junction edge (10) connecting said fin (9) to said main body (5), such that said fins (9) protrude from said main body (5) from the respective junction edge (10) thereof, the surgical implant (1) being characterized in that each fin (9) has a sufficient flexibility so that it can be deformed along a direction centripetal and/or parallel to the longitudinal axis (X-X?) under the action of at least one of the bone bodies (2, 3) when said surgical implant (1) is inserted between said bone bodies (2, 3). Surgical implants.

Abstract: An implant suitable for being anchored with the aid of mechanical vibration in an opening provided in bone tissue. The implant is compressible in the direction of a compression axis under local enlargement of a distance between a peripheral implant surface and the compression axis. The implant includes a coupling-in face which serves for coupling a compressing force and the mechanical vibrations into the implant, which coupling-in face is not parallel to the compression axis. The implant also includes a thermoplastic material which, in areas of the local distance enlargement, forms at least a part of the peripheral surface of the implant.

Abstract: Methods and implants to treat anterior cruciate ligament (ACL) injuries are disclosed. The methods involve advancing the insertion of the patellar tendon to the proximal tibia by means of a partial osteotomy and a wedge-shaped cage (30). The wedge-shaped cage is specifically designed to facilitate transfer of not only compressive loads, but also of shear loads due to pull by the patellar tendon at its insertion to the tibial tuberosity. The cage decreases the angle between the patellar tendon and the common tangent plane formed by the condyles of the femur and the condyles of the tibia (sometimes called tibial plateau) and consequently modifies the internal joint force, restoring stability to the joint even if the ACL is ruptured. The methods and implants are applicable to both human and canine patients.

Abstract: A device for closing a hole in a sphenoid bone that acts as a barrier between a sella turcica and a sphenoid sinus is disclosed. The device includes a cap and a stem. The cap is formed of a deformable material. The cap includes a contact surface and an upper surface. The contact surface forms a base of the cap and includes an outer perimeter. The upper surface includes an apex offset from the contact surface. The upper surface extends from the apex to the outer perimeter. The stem extends from the contact surface in a direction opposite the apex.

Abstract: To favorably discharge gas internally present in a device during filling of a bone filling material, a bone treatment system has a shaft that has a flow path which enables a bone filling material to be placed on a space of a radius to flow therethrough, and a filling balloon that communicates with the flow path in a distal portion of the shaft and that is filled with the bone filling material. Furthermore, the bone treatment system includes a gas discharge portion that causes air (gas) inside the flow path to flow in a direction toward a proximal end rather than the filling balloon, when the bone filling material is supplied to the flow path.

Abstract: Provided is a material for preventing bone cement from leaking out from bone during packing of the bone cement into a bone fracture site. The bone cement can be prevented from leaking out from the bone by employing a three-dimensional structure produced from a material containing a polyhydroxyalkanoate, when packing the bone cement into the bone fracture site.

Abstract: A modular femoral prosthesis for use during performance of a hip revision procedure includes a proximal body component, a distal stem component, and a locking bolt. Surgical instruments and methods for use in implanting such a modular femoral prosthesis are disclosed.

Abstract: A plug for plugging a hole of a bone or implant body during injection of an osteoregenerative material comprising, generally, a plug body, the plug body configured to plug a hole of the body to prevent osteoregenerative material from leaking through the hole, and a tail, the tail attached to the plug body for use in removing the plug body from the hole. In one embodiment, the plug body has an insertion cavity on a trailing end thereof for use in inserting the plug into a hole of the body. The plug body preferably has a frustoconical configuration. The plug body is preferably made of a resilient material, such as silicon.

Abstract: A bone repairing kit including a drilling device, a pushing device, a clamping member and a hole saw. An end of a tube body of the drilling device is a knife portion. When the tube body rotates with respect to a femur, a bone column is cut by the knife portion and located in the tube body. The pushing device includes a hollow tube and a push bar. The hollow tube is for receiving the tube body. The push bar is for touching and pushing the bone column in the tube body. The clamping member is for clamping the bone column. The hole saw includes a receiving body and cutting knives. The receiving body has a recess for receiving an end of the bone column. The cutting knives surrounding on an inner wall of the recess are for cutting an edge of the end of the bone column.

Abstract: Implantable devices for the surgical treatment of bone, and particularly to a bone defect at a joint region, and even more particularly at the subchondral bone level of the joint region, are disclosed. The implantable devices may be formed of a bone material, and configured to serve the dual functions of providing mechanical strength and structural integrity to the area to be treated, while also facilitating the dispersal of a flowable material in the same area. Associated delivery tools are also provided.

Abstract: A guide apparatus including a body having a proximal end, a distal end, a hole formed therethrough, and a central axis defined therethrough, and a projection member coupled to the distal end of the body. An outer diameter of the body is larger than an outer diameter of the projection member. Further, the projection member does not obstruct a pathway defined by the hole.

Abstract: A graft attachment apparatus including at least two separately formed filament loops, and a fixation member comprising at least one opening configured to receive the at least two separately formed filament loops. The at least two separately formed filament loops are coupled to the fixation member. Further, each of the at least two separately formed filament loops are continuous loops.

Abstract: Instruments for use with a bone anchoring assembly having plug member are disclosed that allow introduction of the plug member and bone cement or other liquid or pasty material into the bone anchor. The bone anchor includes a shaft having a first end and a second end, a channel extending from the first end to the second end, and a plug member which is insertable into the channel and guidable through the channel for closing the channel at the second end. The bone anchor is suitable for minimally invasive surgery in such a way a guide wire can be guided through the bone anchor and after the bone anchor has been anchored in the bone the plug member is inserted to close the open end of the bone anchor.

Abstract: A bone repairing kit including a drilling device, a pushing device, a clamping member and a hole saw is provided. An end of a tube body of the drilling device is a knife portion. When the tube body rotates with respect to a femur, a bone column is cut by the knife portion and located in the tube body. The pushing device includes a hollow tube and a push bar. The hollow tube is for receiving the tube body. The push bar is for touching and pushing the bone column in the tube body. The clamping member is for clamping the bone column. The hole saw includes a receiving body and cutting knives. The receiving body has a recess for receiving an end of the bone column. The cutting knives surrounding on an inner wall of the recess are for cutting an edge of the end of the bone column.

Abstract: The present embodiments relate to a joint treatment device for improved treatment of a diseased joint. The joint treatment device comprises first and second components, which are coupled to first and second bone portions, respectively, at the joint. The first component and the second component are configured to be coupled together in a first configuration to promote fusion of the joint, and further are configured to be coupled together in a second configuration to promote arthroplasty of the joint. Additionally, a screwdriver is disclosed that may advance the first and second component simultaneously or independently. Further, a joint distraction device is disclosed, which may be used to vary spacing between the first bone portion and the second bone portion at the joint.

Abstract: The present invention relates generally to medical devices and medical methods, in particular, devices and methods useful for stabilizing fractures of long bones. In one embodiment, the present invention is a device comprising a housing having a lumen; a plunger having a proximal portion and a distal portion, where the plunger is disposed within the lumen and is movable relative to the housing; a plurality of blades, where the blades can expand radially from the axis of the housing; and a manipulator functionally connected to the plunger, wherein the manipulator is operable to: move the plunger relative to the housing; expand the blades radially from the axis of the housing; and move the blades about the axis of the plunger.

Abstract: Methods and instruments for treating an osteoporotic vertebral body or for treating a vertebral compression fracture. An exemplary method includes introducing an open knit structure together with a bone cement into a bone wherein the knit structure extends substantially throughout the interior of the cement volume. In one aspect of the invention, the bone cement volumes cures with the filament structure reinforcing the cement. In another aspect of the invention, the open knit structure is configured to direct flows of bone cement to apply forces for reducing a vertebral compression fracture. In another aspect of the invention, the system provides bone cement flows that extend through the knit structure thus allowing the cement to fully interdigitate with the cancellous bone.

Abstract: An implantable segmented intramedullary structure adapted to be received in the intramedullary canal of a bone configurable between a relatively flexible, bent configuration for implantation or extraction and a relatively rigid, straightened configuration for bone treatment. The segmented intramedullary structure comprises a plurality of interconnected segments with a first interface and a complementarily-shaped second interface such that the first interface of a segment cooperatively engages the second interface of an adjacent segment. The segments define a channel for a tensioning member to lock the structure in a compressed configuration.

Abstract: The present invention relates generally to medical devices and medical methods, in particular, devices and methods useful for stabilizing compression fractures of the spine. In one embodiment, the present invention is a device comprising a housing having a lumen; a plunger having a proximal portion and a distal portion, where the plunger is disposed within the lumen and is movable relative to the housing; a plurality of blades, where the blades can expand radially from the axis of the housing; and a manipulator functionally connected to the plunger, wherein the manipulator is operable to: move the plunger relative to the housing; expand the blades radially from the axis of the housing; and move the blades about the axis of the plunger.

Abstract: An internal bone fixation sizing device and methods for using this device during a procedure for repairing a weakened or fractured bone are disclosed herein. A medical device for determining a depth and a diameter of a medullary cavity of a bone includes an outer shaft having a proximal end engaging an activation mechanism, a distal end having a first opening at an upper surface and a second opening at a lower surface, and a longitudinal axis between the proximal end and the distal end, wherein the longitudinal axis of the outer shaft includes a plurality of markers; and an inner shaft having a proximal end engaging the activation mechanism, a distal end terminating in two sizing arms, and a longitudinal axis therebetween, wherein the two sizing arms are able to move from a retracted position to an extended position extending beyond the outer shaft.

Abstract: A method and devices for facilitating fixating and joining of bone fractures utilizing expandable devices that are positioned within the bone and across the fracture site. The stress from the expanded may enhance and expedite bone healing.

Abstract: A cement restrictor for use in surgical procedures such as total hip replacement, for example, includes a pressure transducer and a transmitter electrically coupled to the pressure transducer. The cement restrictor is configured to be placed at a distal end of a pre-drilled bone canal in a patient's femur, for example, such that the pressure transducer may generate an output signal in response to the presence of bone cement injected into the bone canal and around the cement restrictor. The transmitter is configured to transmit this output pressure signal to an external receiver outside the patient's body.

Abstract: A surgical instrument and method are provided for positioning an osteochondral plug within a bone defect site. The instrument includes an elongate shaft, a ribbon, an elongate sleeve and a locking mechanism. The shaft has proximal and distal ends, with the distal end being shaped to contact the osteochondral plug. The ribbon extends along two sides of the shaft and around the distal end, forming a loop that is used to secure the osteochondral plug to the distal end. The sleeve is movably mounted to the shaft for reciprocating relative thereto between retracted and extended positions. The sleeve includes a slot that allows for visualization and cutting of the ribbon. The locking mechanism locks the ribbon in place and thereby controls the size and tension of the loop that surrounds the osteochondral plug, securing it to the distal end of the shaft.

Abstract: The present invention relates to pedicle implements, in particular pedicle implants that involve screws. The present invention includes a handle, a pointy tip, a shaft, a cannula located therethrough and mini protrusions used to prevent toggling. The crux of the present invention is the ability of the user to create an accurate pilot hole via the pointy tip. In addition, the present invention allows the user the ability to insert a pedicle probe through the cannula out through the pointy tip. This allows the user to perform the cannulation portion of the procedure without the use of any thrombatic agents.

Abstract: A surgical instrument and method are provided for positioning an osteochondral plug within a bone defect site. The instrument includes an elongate shaft, a ribbon, an elongate sleeve and a locking mechanism. The shaft has proximal and distal ends, with the distal end being shaped to contact the osteochondral plug. The ribbon extends along two sides of the shaft and around the distal end, forming a loop that is used to secure the osteochondral plug to the distal end. The sleeve is movably mounted to the shaft for reciprocating relative thereto between retracted and extended positions. The sleeve includes a slot that allows for visualization and cutting of the ribbon. The locking mechanism locks the ribbon in place and thereby controls the size and tension of the loop that surrounds the osteochondral plug, securing it to the distal end of the shaft.

Abstract: A method for forming a tunnel in a bone. The method includes forming a first tunnel in the bone, the tunnel having a longitudinal axis, inserting a first drill guide into the first tunnel, supporting a first tunnel-forming device along an axis defining a first offset relative the longitudinal axis of the first tunnel with the first drill guide, and forming a second tunnel alongside the first tunnel with the first tunnel-forming device, the second tunnel communicating with the first tunnel and defining a single elongated opening.

Abstract: A lesion or fistula isolating bag, the bag defining a first chamber having a closeable entrance and a second chamber for application to a lesion or fistula and wherein access to the second chamber is made through the first chamber via a valve, the valve being arranged to inhibit passage of fluid from the second chamber to the first, and to allow said access from the first chamber to the second, the bag further comprising a closure for said closeable entrance.

Abstract: A graft formation and delivery instrument comprising an outer barrel, a piston, and an inner pin. The outer barrel has a center aperture. The piston is seated within the center aperture, has a through bore, and is operable to move within the center aperture. The inner pin is seated within the through bore of the piston and operable to move within the through bore. The outer barrel receives multiple graft components that are contacted by at least one of the piston and the inner pin to assemble a composite graft from the graft components. The instrument is operable to direct the composite graft to a desired implant area and deposit the composite graft at the implant area.

Abstract: A hip stem centralizer and method are provided for positioning a proximal portion of a femoral hip stem component at a desired radial position within an intramedullary canal of a femur. The hip stem centralizer includes a resilient opening that is elastically compressed upon receiving the hip stem to bias the hip stem to a desired position in the intramedullary canal.

Abstract: In a closure device for an opening in a layer of tissue comprising a plurality of wings which provide and/or hold bearing areas on tissue surrounding the opening, the wings are held by means of respective joints for swivelling movement on a base part.

Abstract: The present invention provides a positioner for controlling the position of a femoral hip implant within the intramedullary canal of a femur.

Abstract: A plug for stopping the flow of bone cement in a channel within bone includes an elastomeric inflatable structure protected from bone fragments and sharp edges by a shield extending around the inflatable structure. The shield may be formed as two or more coaxial structures having flexible members extending between opposite ends, with flexible members from an inner such structure curving outward to lie between adjacent flexible members from an outer such structure as the inflatable structure is inflated. The core is also removably connected to an insertion tool, with passageways in the insertion tool and in the core being used to insert a fluid into the inflatable structure. A valve extends as a sleeve around the core, and over the passageway, allowing fluid to flow into the inflatable structure, but preventing it from flowing out of the inflatable structure.

Abstract: Apparatus and methods are disposed for maintaining the proper positioning of a prosthetic implant having proximal and distal ends within a prepared bone cavity during cement injection and curing. First stabilization means, implantable within the bone cavity, minimize lateral movement of the distal end of the implant, while second stabilization means, physically separate from the means for minimizing lateral movement of the distal end of the implant, minimize both the lateral movement of the proximal end of the implant and the rotational movement of the implant overall. In the preferred embodiment, the second stabilization means includes an apertured cap removably securable to the end of a bone having the prepared cavity through which the implant is inserted and held in place.

Abstract: A plug for insertion into a bone canal is disclosed. The plug comprises an elongate central body of substantially constant cross section carrying at least four radially extending flanges of substantially equal shape and size. The flanges form solid, disk-like structures, free of cuts and are axially spaced along the central axis of the body, such that they extend in substantially parallel planes. The plug is made of a copolymer of a polyalkylene glycol terephthalate and an aromatic polyester.

Abstract: Shrouds for use with an implant in order to allow a surgeon to determine when the implant has been inserted into the femoral canal (or other bone as applicable) a proper distance during implantation. Such a shroud is useful to ensure that the patient's limb after prosthesis implantation is the correct length. The shrouds described have a distal surface which, when properly positioned relative to the implant, indicate proper insertion distance, such as by abutting a portion of the femur upon reaching correct insertion distance. The shrouds may contain a cavity which receives all or part of the neck or taper of the implant in order to position the distal surface correctly. The shrouds described can also help determine correct version of the implant, retain cement in the bone canal or cavity during implantation, pressurize the cement, and protect surfaces of the implant during the implantation.

Abstract: A bone plug (61), for blocking of a canal in a bone, has a solid body which by axial compression expands in the radial direction. The height of the body is at most 6 times the average wall thickness of the body. The body (65) is preferably made out of an elastomeric material. For keeping the body (65) axially locked the bone plug comprises a first locking element (67) which is formed by a disc (69) with attached to it a stem (71) provided with saw tooth shaped protrusions (73) which protrudes through an axial opening in the body (65) and a second locking element (75) which is formed by an interrupted ring (77) and an annular plate (79), which are positioned around the stem (71). The ring (77) locks behind one of the protrusions (73) and the annular plate (79) is positioned between the interrupted ring (77) and the body (65). Fixating of the bone plug (61) in the canal is carried out by pushing the interrupted ring (77) along the stem (71) until it locks behind one of the protrusions.

Abstract: The kit for implanting a cementable endoprosthesis includes a fitting instrument and at least two components to be implanted, namely an endoprosthesis shaft and a proximal centering and/or sealing element, the shaft and the fitting instrument being designed to be able to be coupled to each other, and the centering and/or sealing element being designed to be placeable on the shaft and to be displaceable in the direction of extension of the latter, and either the fitting instrument including a limit stop part which forms a limit stop relative to the centering and/or sealing element, or a marking being arranged on the fitting instrument and on the shaft in order to ensure a defined mutual position between the centering and/or sealing element and the shaft.

Abstract: An arthroplasty prosthesis cement restrictor comprises a cylinderlike body having a hexagonal lateral outside cross section. A set of corresponding longitudinal external ridges are disposed along the points of the hexagonal lateral cross section. A spiraling machine-thread is formed in the set of corresponding longitudinal ridges and provides for a threaded positive lock of the cylinderlike body into the walls of a long-bone intramedullary canal. A capped end is disposed at one end of the cylinderlike body and provides for the stoppage of cement injected during arthroplasty into the more distal parts of the intramedullary canal. A number of corresponding longitudinal fenestrations are disposed between the set of corresponding of longitudinal ridges which can be flooded with cement to allow cement contact with the adjacent bone.

Abstract: A device and method for joint replacement surgery, such as total hip replacement surgery, including a bone cement plug which is adaptable to any size bone canal, an insertion tool for deploying the plug in the canal, and a cradle for storing the plug and insertion tool, The bone cement plug comprises a body defined by a series of separable units, each with a flange. The flanges decrease in diameter from the proximal end of the body to the distal end of the body. For smaller canals that cannot receive the large flanges, appropriate units of the plug may be removed, thus eliminating the oversized flanges in favor of the more appropriately sized flanges.

Abstract: A plug for stopping the flow of bone cement in a bone channel, such as the intramedullary bone canal, or a previously prepared channel, includes an actuator and a number of flexible beams extending around the bone plug. The actuator is removably attached to a rod within an insertion tool used to deploy the bone plug at a predetermined location within the channel. Within the tool, the rod is pulled to move the actuator into a position applying a compressive force to act between the ends of each of the flexible beams. This compressive force causes each beam to buckle outward, into contact with the channel. The rod is then released from the actuator, and the tool is withrawn from the channel so that bone cement can be applied to hold a prosthesis in place within the channel in a proximal direction from the bone plug.

Abstract: Surface irregularities are removed from the inner wall of a femur cavity, preferably tapered. A tamp having an opening and a socket is disposed in the cavity. The tamp may be one of a plurality of tamps each having a different length for the opening. A guide, one of a plurality, fits snugly in the opening. The guide has a collar which cooperates with the tamp socket to limit the movement of the guide into the tamp. A working portion of each guide below the intermediate position has a bulbous shape which is tapered in accordance with the femur taper. Bone fragments between the guide working portion and the femur inner wall are packed against the inner wall when the tamp and the guide are driven into the femur cavity. Numerals on the guide adjacent a slot in the tamp indicate the disposition of the guide in the tamp.

Abstract: A plug for stopping the flow of bone cement in a channel within bone includes an elastomeric inflatable structure protected from bone fragments and sharp edges by a shield extending around the inflatable structure. The shield may be formed as two or more coaxial structures having flexible members extending between opposite ends, with flexible members from an inner such structure curving outward to lie between adjacent flexible members from an outer such structure as the inflatable structure is inflated. The core is also removably connected to an insertion tool, with passageways in the insertion tool and in the core being used to insert a fluid into the inflatable structure. A valve extends as a sleeve around the core, and over the passageway, allowing fluid to flow into the inflatable structure, but preventing it from flowing out of the inflatable structure.

Abstract: An apparatus for locating interlocking intramedullary nails comprises a slide device which is disposed at the near end of the nails and is capable of adjustment in various directions. The slide device is provided with a locking structure, a locating rod, or drilling guide sleeve. The relative positions of the near end and the far end threaded holes of the interlocking intramedullary nails of various hole intervals and specifications are adjusted by the slide device in accordance with the body size of a patient under treatment. The drilling position of the drilling guide sleeve can be attained with precision and speed.

Abstract: A plug for stopping the flow of bone cement in a channel within bone, such as the intramedullary bone canal or a previously prepared channel, includes an elastomeric inflatable structure protected from bone fragments and sharp edges by a shield extending around distal and peripheral sides of the inflatable structure. This inflatable structure is preferably formed as a sleeve extending around a core. The shield includes a distal end fastened to the core and a flexible portion expandable with inflation of the inflatable structure. The core is also removably connected to an insertion tool, with passageways in the insertion tool and in the core being used to insert a fluid into the inflatable structure. A valve extends as a sleeve around the core, and over the passageway, allowing fluid to flow into the inflatable structure, but preventing it from flowing out of the inflatable structure.

Abstract: A core for forming a bone cement plug for deployment in a bone canal, the core including a base portion defining a bore having internal teeth therein and extending axially and distally from a proximal end of the base portion. A first leg portion depends from and extends distally from the base portion, the first leg portion having a first protrusion at a distal end thereof extending outwardly from an outside wall of the first leg portion through a first arc, and a second leg portion depends from and extends distally from the base portion, the second leg portion having a second protrusion at a distal end thereof extending outwardly from an outside wall of the second leg portion through a second arc and oppositely to the first arc. The toothed bore of the base portion is adapted to receive an expander member to wedge apart the first and second leg portions to expand the core widthwise to secure the core in the bone canal.

Abstract: A plug for stopping the flow of bone cement in a channel within bone, such as the intramedullary bone canal, forming a channel, or a previously prepared channel, includes an actuator and a number of flexible beams extending around the bone plug. The actuator is removably attached to a rod within an insertion tool used to deploy the bone plug at a predetermined location within the channel. Within the tool, the rod is pulled to move the actuator into a position applying a compressive force to act between the ends of each of the flexible beams. This compressive force causes each beam to buckle outward, into contact with the channel. The rod is then released from the actuator, and the tool is withdrawn from the channel so that bone cement can be applied to hold a prosthesis in place within the channel in a proximal direction from the bone plug.

Abstract: Apparatus and methods are disposed for maintaining the proper positioning of a prosthetic implant having proximal and distal ends within a prepared bone cavity during cement injection and curing. First stabilization means, implantable within the bone cavity, minimize lateral movement of the distal end of the implant, while second stabilization means, physically separate from the means for minimizing lateral movement of the distal end of the implant, minimize both the lateral movement of the proximal end of the implant and the rotational movement of the implant overall. In the preferred embodiment, the second stabilization means includes an apertured cap removably securable to the end of a bone having the prepared cavity through which the implant is inserted and held in place.

Abstract: A prosthesis provided with a stem at least part of which is enclosed in a mantle and which is for insertion in a bone cavity and attachment thereto by cement, said mantle having a wall thickness which is increased towards its proximal end to provide an outwardly projecting proximal balcony and which is dimensioned and adapted to locate the stem in a predetermined position within the cross-sectional area of the bone cavity at or towards the proximal end thereof.

Abstract: An alignable orthopedic prosthesis system includes a prosthesis and an alignment guide. The prosthesis includes a stem having at least one keyed component extending along its outer surface. The alignment guide has an alignment body with a guide surface disposed on an inner portion thereof. The guide surface has a key element formed therein for engageably receiving the keyed component of the prosthesis.

Abstract: The kit for implanting a cementable endoprosthesis comprises a fitting instrument (3) and at least two components to be implanted, namely an endoprosthesis shaft (4) and a proximal centering and/or sealing element (1), the shaft (4) and the fitting instrument (3) being designed to be able to be coupled to each other, and the centering and/or sealing element (1) being designed to be placeable on the shaft (4) and to be displaceable in the direction of extension of the latter, and either the fitting instrument (3) comprising a limit stop part (3e) which forms a limit stop relative to the centering and/or sealing element (1), or a marking (6) being arranged on the fitting instrument (3) and on the shaft (4) in order to ensure a defined mutual position between the centering and/or sealing element (1) and the shaft (4).