Patent Description:
Modular implants that are adaptable to a patient have been a success for replacing synovial joints. Such a replacement may become necessary due to arthritis or trauma. The modularity of these implants allows for highly customized joint replacements at reasonable costs.

<CIT> discloses a surgical tool for inserting and removing a joint head prosthesis, particularly for a hip.

<CIT> discloses an impactor/extractor holder for a femoral trial and/or a knee implant to hold and guide those items onto the resected end of a femur.

<CIT> discloses an implant for resurfacing a joint and a driver for the implant. The inserter attaches to the head of the implant and is designed to facilitate the handling and insertion of an implant at a surgical site.

<CIT> discloses an instrument for use in removal of a prosthetic implant for use in performing arthroplasty.

<CIT> discloses a vertebral body replacement device includes a body member and a central rod member having two threaded portions and configured to be operatively associated with the body member.

Nonetheless, the stability and reliability of the connection between implant components of these modular joint implants is crucial for their longevity. In this respect, a common technique for connecting implant components is the use of a tapered connection, which causes a friction fit between components. This type of connection is particularly employed for compressive forces since these forces cause self-locking of this type of connection. An exemplary application of a tapered connection is in a joint implant. A joint implant typically comprises a stem for anchoring the implant within the bone tissue of a bone adjacent to a joint to be replaced. After implantation of the stem, an implant component including a joint surface may be attached to the stem. This attachment is mostly achieved using above-noted tapered connection.

Although these tapered connections have been proven as an effective way to connect implant components to each other, this effectiveness also renders it difficult to adjust the orientation of an implant component or replace such a component by another one, once it has been assembled. In other words, having established the friction fit within the tapered connection, it is necessary for an adjustment or removal to pull the implant components apart from each other along an axial direction of the tapered connection. This is typically achieved using a hammer-like tool that applies an impulse to a component attached to the stem for loosening the tapered connection. As a result, there is a risk of affecting the connection between the implant's stem and the bone tissue of a patient.

Thus, it was an objective to provide an implantation tool for assembling components of a joint implant, in particular components that are attachable to each other by a friction fit.

It has also been an objective to provide an implantation tool that allows for an adjustment of the orientation of implant components relative to each other or for a replacement of an implant component after assembly, while preventing an effect on the anchorage of the implant's stem within the bone tissue of a patient.

The present disclosure addresses these objectives by providing a tool according to claim <NUM>, an implantation set according to claim <NUM> and comprising such a tool, an assembly method according to claim <NUM> using such a tool and a disassembly method according to claim <NUM> using such a tool.

A tool for assembling and disassembling a first implant component and a second implant component is provided. The tool comprises a proximal end, a distal end, and a longitudinal axis. It further comprises an elongated force transmission structure for transmitting a force in a direction along the longitudinal axis, wherein the force transmission structure includes a proximally facing contact surface. The tool also comprises two elongated retaining elements, wherein each retaining element has a distally facing retaining surface at a proximal end thereof, and an actuation mechanism. The actuation mechanism is operable to move the retaining elements between a standby position and a retaining position, wherein in the retaining position the proximal ends of the retaining elements are closer to each other than in the standby position. A further actuation of the actuation mechanism after assuming the retaining position causes a relative movement of the contact surface in relation to the retaining surfaces in a proximal direction.

The elongated force transmission structure allows for transmitting a force, in particular caused by an impact force applied to the distal end with a tool (e. a hammer) from the distal end to the proximal end of the force transmission structure (i. to the first implant component).

In other words, the force transmission structure serves as an intermediate means to transmit and direct an impact force to the first implant component for assembling the first implant component to the second implant component.

Consequently, the elongated force transmission structure is able to protect the first component from direct contact with the impact tool by guiding and directing the impact force to the first component. This prevents the first component from being damaged by the impact force during fixation of the first implant component to the second implant component that may otherwise be caused by a more direct and less controlled application of the impact force.

The retaining elements are for retaining the first implant component during assembly and disassembly of this component to and from the second component. In the standby position, the elongated retaining elements are positioned relative to each other for receiving the first implant component. In particular, the retaining elements are positioned for placing the first implant component on their distally facing retaining surfaces.

Then, the actuation mechanism is configured to move the retaining elements to the retaining position for retaining the first implant component. In the retaining position, the first implant component preferably rests on the distally facing retaining surface and in between the retaining elements. The retaining elements allow for easy handling of the first implant component during assembly and disassembly.

During disassembly, the relative movement of the contact surface of the force transmission structure in relation to the retaining surfaces of the elongated retaining elements may be used for a pull-off movement of the first implant component in relation to the second implant component.

More specifically, the contact surface of the force transmission structure may be in contact with the second implant component. In this state, the further actuation of the actuation mechanism may cause a movement of the contact surface in the proximal direction so that the distally facing retaining surfaces move distally in relation to the contact surface. As a result, the first implant component also moves distally so that a connection, in particular a friction fit (e. by a tapered connection), between the first implant component and the second implant component is released.

Thus, the further actuation of the actuation mechanism facilitates the disassembly of the first and second implant components without affecting the fixation of the implant to the bone tissue of a patient.

The actuation mechanism is particularly configured to convert a translational movement into a rotational movement of the retaining elements and, when the rotational movement of the retaining elements is blocked, to transfer the translational movement to the retaining elements for causing the relative movement of the distally facing retaining surfaces in relation to the contact surface in a distal direction.

In particular, the translational movement is a translational movement (preferably in the direction of the longitudinal axis) relative to the elongated force transmission structure and its proximally facing contact surface. The actuation mechanism then converts this translational movement to a rotational movement of the retaining elements so that the proximal ends of the retaining elements rotate towards each other for assuming the retaining position.

If this rotational movement of the elongated retaining elements is blocked, the conversion of the translational movement to the rotational movement is stopped. Instead, the translational movement is directly transferred to the elongated retaining elements causing above-noted relative movement to the contact surface in the distal direction. In other words, the translational movement after the rotational movement is blocked corresponds to the further actuation.

Blocking of the rotational movement is particularly caused by the first implant component being present in between the proximal retaining elements and on the distally facing retaining surfaces. As a result, sides of the retaining elements facing each other may get in contact with the first implant component and block the rotational movement. Nonetheless, any blockage of the rotation may cause the transferal of the translational movement to the retaining elements.

As a result of the actuation mechanism being configured like this, an operator does not have to switch actuation modes since the actuation mechanism is configured as described above.

Preferably, the retaining elements are configured to perform at their proximal ends a gripping motion towards each other to assume the retaining position and a release motion away from each other to assume the standby position.

The gripping motion allows for capturing the first implant component between the elongated retaining elements and the contact surface of the force transmission structure. In the retaining position, the retaining surfaces of the retaining elements prevent a movement of the first implant component in a proximal direction, whereas the contact surface prevents a movement of the first implant component in a distal direction.

Accordingly, the release motion allows to release the first implant component from the tool after assembly or disassembly. This configuration of the retaining elements provides for a secure and easy handling of the first implant component during assembly and disassembly.

The tool may further comprise a base member, wherein the retaining elements are each pivotable about a rotation axis having a fixed position on the base member.

This configuration not only allows for a defined movement of the retaining elements relative to the contact surface of the force transmission structure and the first implant component but also for a predetermined movement of the retaining elements relative to each other.

It is particularly preferred that the actuation mechanism further comprises an actuation member, wherein the actuation member is arranged between distal ends of the retaining elements and includes a distally tapered portion. The distal ends of the retaining elements are in contact with a slanted surface of the distally tapered portion.

This configuration including an actuation member presents a way to guide the distal ends of the retaining elements away from and towards each other. More specifically, a movement of the actuation member in the distal direction relative to the retaining elements causes the distal ends of the retaining elements to move along the slanted surface to a wider section of the actuation member's distally tapered portion, which results in an increased distance between these distal ends and vice versa.

If used in combination with the retaining elements having above-noted rotation axis at the base member, the distal movement of the actuation member causes a movement of the retaining elements towards the retaining position (i. towards each other), whereas a proximal movement of the actuation member causes a movement of the retaining elements towards the standby position (i. away from each other).

The actuation member of this configuration provides a simple and effective mechanism to transform a longitudinal movement into a rotational movement of the two elongated retaining elements. Further, it allows for adjusting the transmission ratio between the longitudinal and rotational movement making it easier for a user to apply the force needed.

As a result of the above, the actuation member is preferably movable relative to the base member along the longitudinal axis. Guided by the contact of the distal ends of the retaining elements with the slanted surface, a movement of the tapered portion relative to the base member distally pushes the distal ends of the retaining elements away from each other and the proximal ends of the retaining elements towards each other.

Further, the actuation mechanism may further comprise a biasing means, wherein the biasing means is arranged between the base member and the actuation member and biases the base member and the actuation member away from each other along the longitudinal axis.

This preferably results in the retaining elements being biased towards the retaining position. This bias also causes the elongated retaining elements of the tool to always assume a defined position relative to each other and relative to the contact surface of the force transmission structure, in particular since the bias keeps the retaining elements and the base member (in particular the slanted surface) in contact. Thus, there is no slack within the mechanisms of the tool when being handled. Having a bias towards the retaining position also prevents the first implant component from accidentally being released from the tool.

The force transmission structure is preferably arranged between the retaining elements and comprises a transmission rod, the transmission rod may have a through hole extending between the distal and proximal ends of the transmission rod for inserting a fastening tool.

Accordingly, the tool comprising the two elongated retaining elements and the interposed force transmission structure may generally have a symmetrical configuration. This allows for a balanced force application during assembly and disassembly of the first and second implant components.

In particular, the transmission rod extends along the longitudinal axis of the tool. The possibility to insert a fastening tool has the advantage that fastening of the implant components is possible without removing the tool for assembly and disassembly.

Preferably, the transmission rod is in a threaded engagement with the actuation member so that a rotation of the transmission rod relative to the actuation member causes a movement of the actuation member along the longitudinal axis relative to transmission rod and in particular relative to the distal ends of the retaining elements.

Consequently, the transmission rod allows a user to easily rotate the transmission rod (preferably at its distal end), which in turn results in a relative movement between the transmission rod and the actuation member in a longitudinal direction. This relative movement of the actuation member particularly causes the retaining elements to move between the standby position and the retaining position.

The threaded engagement of the transmission rod and the actuation member also has the advantage that it allows for a transmission ratio enabling a precise, easy, and controlled movement of the retaining elements as well as assembly and disassembly of the implant components.

It should be noted that the base member particularly has a central through hole for guiding the transmission rod so that the transmission rod may move along and rotate freely relative to this through hole.

The force transmission structure further preferably comprises an adapter including the contact surface at a proximal end of the adapter and a rod coupling portion at a distal end of the adapter, wherein the rod coupling portion preferably allows for a relative rotation between the adapter and the transmission rod about the longitudinal axis.

Employing an adapter at the proximal end of the transmission rod allows for adaptation of the contact surface to the distal surface of the first implant component. This has the advantage of enhancing the support of the tool. Further, the adapter may prevent a rotation during actuation of the transmission rod by a user.

The enhanced support for the force transmission structure by the adapter at the proximal end of the transmission rod particularly provides a basis for the relative movements from the transmission rod to the actuation member, from the actuation member to the retaining elements and from the retaining elements relative to the first implant component.

The adapter is preferably an assembly adapter for being in contact with the first joint implant component and/or a disassembly adapter for being in contact with the second joint implant component.

When being configured as an assembly adapter, the contact surface of the adapter is preferably in contact with a distal surface, in particular a joint surface, of the first implant component for supporting the tool.

When being configured as a disassembly adapter, the support surface of the adapter is in contact with a distal surface of the second implant component, for example via a through hole through the first implant component, and acts as a support for the tool during disassembly. In this case, the actuation of the tool causes a relative movement between the distally facing retaining surfaces of the retaining elements and the contact surface of the transmission rod (and in particular of the adapter) so that the first implant component and the second implant component move away from each other.

The disclosure further provides an implantation set comprising a tool configured as described above, a first implant component, and a second implant component. The first implant component includes a first connecting portion formed at a proximal end thereof and a through hole with a screw seat for an assembly screw. The through hole extends between the proximal end and a distal end of the first implant component, wherein the first implant component preferably comprises a joint surface at the distal end. The second implant component includes a second connecting portion formed at a distal end thereof and a threaded hole for receiving the assembly screw.

Consequently, this implantation set provides above described advantages resulting in an easy assembly and disassembly of the first and second implant components.

Preferably, the through hole of the first implant component at the screw seat is threaded and even more preferably in the opposite direction in relation to the threaded hole of the second implant component for capturing the assembly screw and serving as a screw seat during fixation. This greatly facilitates handling of the first implant component together with the assembly screw by enabling a pre-assembly of these components.

As a result of this configuration, the assembly screw preferably has an outer thread on the circumferential surface of the assembly screw's head, an outer thread at the opposite end of the assembly screw, and an intermediate section in between, wherein the intermediate section has a smaller diameter than the base diameter of each of these outer threads.

Preferably, one of the first connecting portion and the second connecting portion comprises a male taper and the other one of the first connecting portion and the second connecting portion comprises a female taper.

Such a tapered connection provides for a reliable and releasable connection between implant components. The angle of the tapered connection is also preferably configured to be self-locking.

The present disclosure further discloses a method for preparing a first implant component for assembly to a second implant component using a tool, in particular a tool that is configured as described above. The tool comprises an actuation mechanism, two elongated retaining elements, and a force transmission structure. The method comprises a step of placing the first implant component between proximal ends and onto distally facing retaining surfaces of the retaining elements, wherein the retaining elements are in a standby position for receiving the first implant component. By actuating the actuation mechanism of the tool, the retaining elements assume a retaining position caused by the retaining elements moving closer to each other and by moving the force transmission structure so that a proximally facing contact surface at the proximal end of the force transmission structure abuts the first implant component.

Accordingly, the method allows to securely and easily handle the first implant component prior to entering the implantation site and assembly to the second implant component.

The present disclosure also provides a method for disassembling a first implant component and a second implant component using a tool, in particular a tool configured as described above. The tool includes an actuation mechanism, two elongated retaining elements, and a force transmission structure, and may comprise the step of loosening an assembly screw that fastens the first implant component to the second implant component. The first implant component is placed between proximal ends and onto distally facing retaining surfaces of the retaining elements, wherein the retaining elements are in a standby position for receiving the first implant component. Then, the actuation mechanism of the tool is actuated for assuming a retaining position by moving the retaining elements closer to each other and by moving the force transmission structure proximally to abut the head of the assembly screw with a proximally facing contact surface at the proximal end of the force transmission structure. After the retaining elements assumed the retaining position, actuating the actuation mechanism continues for moving the retaining elements distally in order to pull the first implant component away from the second implant component.

This method is particularly directed at a connection between implant components that is based on a friction fit.

Disassembling the first implant component and the second implant component advantageously releases the two implant components from each other in a controlled and defined way without exerting an impact force on the patient that may adversely affect the interface formed between the bone tissue and the implant. In other words, this method achieves disassembly of the implant components without the need for an impact tool such as a hammer to release the implant components from each other.

In this way, surgery is performed more gently, which supports a faster recovery of the patient. Also, the implant may be more easily adapted to an anatomic environment (e. properties of tendons and muscles) that has changed over time due to aging of the patient. If needed, the replacement of worn implant components, in particular joint surfaces, is facilitated, which significantly increases the lifetime of the implant.

In the following, exemplary configurations of tools for assembling and disassembling implant components according to the present disclosure are described under reference to the attached drawings that illustrate preferred embodiments of these tools.

<FIG> illustrates an exemplary embodiment of the tool <NUM> for assembling and disassembling implant components. The tool <NUM> may, for example, be used for an implantation or revision of an implant component. However, the skilled person appreciates that the assembly and disassembly of implant components may also take place outside of a patient's body.

The tool <NUM> has a distal end <NUM> and a proximal end <NUM> at opposite ends of the tool's longitudinal axis L. When being used during an implantation or revision of an implant component, the distal end <NUM> is directed away from whereas the proximal end <NUM> is directed towards the patient's body.

Further, the tool <NUM> includes a force transmission structure <NUM> for transmitting an assembly force (in particular a compressive force or an impact force for causing a friction fit) along the longitudinal axis L of the tool <NUM>, a retaining mechanism <NUM> for retaining a first implant component <NUM> (see <FIG>), and an actuation mechanism <NUM> for actuating the retaining mechanism <NUM>.

The force transmission structure <NUM> extends from the distal end <NUM> towards the proximal end <NUM> of the tool <NUM> and includes a transmission rod <NUM> for transferring a force along the longitudinal axis between the proximal and distal ends of the force transmission structure <NUM>. The transmission rod <NUM> is preferably integrally formed.

At the distal end <NUM>, the force transmission structure <NUM> and in particular the transmission rod <NUM> may have an impact face <NUM> for exerting an impact force to the force transmission structure <NUM> that is then transmitted to the proximal end of this structure, where it can be applied to an implant component. An impact force is typically applied during assembly of a first implant component <NUM> and a second implant component <NUM> for fixing these implant components to each other (see <FIG>).

At the proximal end, the transmission rod <NUM> may have a contact surface (not shown in this embodiment) for being in contact with an implant component <NUM> or <NUM> during assembly or disassembly.

Nonetheless, the proximal end preferably includes a rod coupling portion <NUM>. This rod coupling portion <NUM> serves for mounting an assembly adapter <NUM> (see <FIG>, <FIG>) or a disassembly adapter <NUM> (see <FIG>, <FIG>).

The adapters <NUM> and <NUM> and the rod coupling portion <NUM> are preferably configured for an assembly using a snap-fit. Nonetheless, this skilled person will appreciate that other means may be used, such as a friction fit or an insertion of one of the rod coupling portion and the adapter into the other one of the rod coupling portion and the adapter, as long as a compressive force can be applied via the transmission rod <NUM> and either one of the adapters <NUM>, <NUM>.

Further, the connection between the transmission rod <NUM> and the adapters <NUM>, <NUM> preferably allows for a relative rotation about the longitudinal axis L.

Extending from its proximal to its distal end, the transmission rod <NUM> may also comprise a through hole <NUM> for a fastening tool <NUM> (see <FIG>). The fastening tool <NUM> may, for example, be used for fastening and unfastening the first implant component <NUM> and the second implant component <NUM> via an assembly screw <NUM> for preventing an unintended loosening of these components (i. to secure them to each other).

Turning to the interaction of the retaining mechanism <NUM> and the actuation mechanism <NUM>, the actuation mechanism <NUM> is for actuating the retaining mechanism <NUM>. By actuating the retaining mechanism <NUM>, the retaining elements <NUM> are able to retain and to release a first implant component <NUM>.

As shown in the figures, the retaining mechanism <NUM> comprises two retaining elements <NUM>. However, the retaining mechanism <NUM> may also comprise more than two retaining elements <NUM>, such as three, four or five retaining elements <NUM>.

The retaining elements <NUM> are elongated and are arranged along the longitudinal axis L with the transmission rod <NUM> located in between.

At their proximal ends, the retaining elements <NUM> are configured to retain an implant component. An implant component <NUM> may be retained between proximal retaining sections <NUM> of the retaining elements <NUM>. These proximal retaining sections <NUM> may enter corresponding retaining recesses <NUM> of the implant component <NUM> so as to retain the implant component <NUM> between these proximal retaining sections <NUM>. The engagement of the proximal retaining sections <NUM> also prevents a rotation of the implant component <NUM> about the longitudinal axis L relative to the tool <NUM>.

The elongated retaining elements <NUM> include distally facing retaining surfaces <NUM> at their proximal ends. In a retaining position, these distally facing retaining surfaces <NUM> prevent a proximal movement of the implant component <NUM> in relation to the tool <NUM>.

As illustrated in the figures, the proximal retaining sections <NUM> of the retaining elements <NUM> may also be formed to extend at a distance along a part of (e. the distally facing) outer contour of a retained implant component <NUM> (first implant component). This configuration limits a movement of the implant component <NUM> in a distal direction, which particularly helps when mounting the first implant component <NUM> to the tool <NUM>.

However, in the retaining position, it is the contact surface <NUM> of the elongated force transmission structure <NUM> that prevents a movement of the implant component <NUM> in the distal direction. More specifically, the implant component <NUM> is retained in the proximal-distal direction between the distally facing retaining surfaces <NUM> and the proximally facing contact surface <NUM>.

Between their proximal and distal ends, the retaining elements <NUM> are pivotably supported about rotation axes <NUM> (see for example <FIG>) by a base member <NUM>. Preferably, the rotation axes <NUM> are located more distally along the retaining elements <NUM>. As illustrated in the figures, the rotation axes <NUM> particularly extend perpendicular to and are arranged symmetrically and at a distance to the longitudinal axis L of the tool <NUM>. However, different configurations are also envisaged such as using one rotation axis <NUM> for the retaining elements <NUM>.

Each of the retaining elements <NUM> includes at its distal end a gliding surface <NUM> facing in a direction towards the longitudinal axis L. As will be explained in the following, these gliding surfaces <NUM> interact with the actuation mechanism <NUM> in order to move (in particular pivot about the rotations axes <NUM>) the retaining elements between a standby position and a retaining position in order to mount and unmount an implant component <NUM> at the proximal retaining section <NUM> of the retaining elements <NUM>.

Turning to the actuation mechanism <NUM>, the actuation mechanism <NUM> comprises an actuation member <NUM>. The actuation member <NUM> includes a distally tapered portion <NUM> formed with a slanted actuation surface <NUM> to be in contact with the gliding surface <NUM> of each retaining element <NUM>. In the exemplary embodiment of the figures, the slanted actuation surface <NUM> comprises two slanted actuation surfaces on opposite sides relative to the longitudinal axis L for interacting with the gliding surfaces <NUM> of the retaining elements <NUM>, respectively. In other words, the slanted actuation surfaces <NUM> are arranged at an angle to the longitudinal axis L and particularly face in a distal direction.

As a result of this configuration, a movement of the actuation member <NUM> and, thus, its slanted actuation surfaces <NUM> along the longitudinal axis L and relative to the base member <NUM> of the retaining mechanism <NUM> causes a movement of the distal ends with the gliding surfaces <NUM> of the retaining elements <NUM> in a perpendicular direction to the longitudinal axis L while rotating about the rotation axes <NUM>.

More specifically, a movement of the actuation member <NUM> in the distal direction causes the distal ends of the retaining elements <NUM> to move away from each other due to the contact of the gliding surfaces <NUM> with the slanted actuation surfaces <NUM> of the actuation member's distally tapered portion <NUM> (cf.

Due to the pivotal support of the retaining elements <NUM> at the base member <NUM>, this movement of the distal ends of the retaining elements <NUM> causes the proximal retaining sections <NUM> to move towards each other. In other words, this movement causes the proximal retaining sections <NUM> to switch between the standby position and the retaining position.

Accordingly, a movement of the actuation member <NUM> in the proximal direction allows for the proximal retaining sections <NUM> to move from the retaining position to the standby position and to release the implant component <NUM> (cf.

As illustrated in <FIG>, the actuation mechanism <NUM> may further include a biasing means <NUM> (e.g. a spring). The biasing means <NUM> is arranged and acts between the base member <NUM> and the actuation member <NUM>. It preferably biases the base member <NUM> and the actuation member <NUM> away from each other along the longitudinal axis L and, thus, towards the retaining position of the retaining elements <NUM>. This has the advantage that the tool <NUM> does not move unintentionally between the retaining position and the standby position.

An operator preferably actuates the actuation mechanism <NUM> via a rotation of the transmission rod <NUM>. More specifically, the transmission rod <NUM> preferably comprises an actuation thread <NUM> that engages an actuation thread <NUM> of the actuation member <NUM>. Consequently, turning the transmission rod <NUM> about the longitudinal axis L while holding the actuation member <NUM> in position (for example using a grip portion <NUM> of the actuation member <NUM>) causes a relative translational movement between the actuation member <NUM> and the transmission rod <NUM> along the longitudinal axis L. For operating the transmission rod <NUM>, the distal end of the transmission rod <NUM> may include an operating section <NUM> such as a knob and/or a recess/through hole for inserting a lever arm.

The operation of the tool <NUM> for assembling and disassembling the implant components <NUM> and <NUM> will now be described under reference to <FIG>.

<FIG>, <FIG> illustrate the process of assembling a first implant component <NUM> to a second implant component <NUM> using a tool <NUM> according to the present disclosure.

<FIG> depicts the tool <NUM> in a standby position for receiving a first implant component <NUM>. In the standby position, the proximal retaining sections <NUM> of the retaining elements <NUM> are at a distance from each other perpendicular to the longitudinal axis L. In this state, the first implant component can preferably pass by the distal ends of the retaining elements <NUM> in a distal direction until being in contact with the contact surface <NUM> of the force transmission structure <NUM>.

Although shown in <FIG>, the second implant component <NUM> is not necessarily present when mounting the first implant component <NUM> to the tool <NUM> in the standby position but may be added later during an assembly of the first implant component <NUM> to the second implant component <NUM> (e. the second implant component <NUM> may already be implanted).

In the exemplary embodiment of <FIG>, the contact surface <NUM> is formed at the proximal end of an assembly adapter <NUM>. As described above, the assembly adapter <NUM> is attached to the proximal end of the transmission rod <NUM> and is in particular rotatable relative to the transmission rod <NUM> about the longitudinal axis L. The contact surface <NUM> is preferably formed so as to correspond to the distally facing surface of the first implant component <NUM> the contact surface <NUM> abuts to.

The assembly adapter <NUM> shown in <FIG> is particularly adapted to a distally facing surface of the implant component <NUM> (e. joint surface) that is symmetrical about the longitudinal axis L in the contact area with the contact surface <NUM>.

In contrast, the assembly adapter <NUM> shown in <FIG> has a contact surface <NUM> configured to be in contact with a distally facing surface of the first implant component <NUM> that is asymmetrical in relation to the longitudinal axis L. In this case, the assembly adapter <NUM> preferably comprises a collar 23a that fits into the aperture of the through hole <NUM> of the first implant component <NUM>. The fit of the collar 23a is adapted to prevent the adapter <NUM> from slipping sideways relative to the longitudinal axis due to the asymmetrical surface <NUM> of the first implant component <NUM>.

In this respect, the adapter <NUM> and the retaining elements <NUM> may also comprise an interacting nose-recess configuration for preventing the adapter <NUM> to rotate about the longitudinal axis L, at least in the retaining position and in particular in case of an asymmetrical surface as described above.

<FIG> shows an example of such a nose-recess configuration. Here, the adapter <NUM> includes a recess 23b and the retaining element <NUM> includes a nose <NUM>. As illustrated in <FIG> with adapter <NUM> in cross-section, the nose <NUM> protrudes into the recess 23b (here formed as a longitudinal groove) when the adapter <NUM> is assembled to the proximal end of the transmission rod <NUM>. In this example, the nose <NUM> is interacting with the recess 23b in both the standby position and the retaining position.

As shown in the figures, the implant components <NUM>, <NUM> to be assembled are preferably joint implant components. Thus, the distally facing surface <NUM> of the first implant component <NUM> is preferably the joint surface of the joint implant. In particular in this case, it is advantageous to adapt the contact surface <NUM> of the assembly adapter <NUM> in order to enhance the distribution of loads, in particular impact loads, during assembly of the first implant component <NUM> to the second implant component <NUM>.

Likewise, the relative rotation that is allowed between the transmission rod <NUM> and the assembly adapter <NUM> prevents a relative rotation between the contact surface <NUM> of the assembly adapter <NUM> and the joint surface of the first implant component <NUM>. As described above, such a rotation may also be prevented by a nose-recess configuration between the adapter <NUM> and the retaining elements <NUM>.

Preferably, the assembly adapter <NUM> is made of a polymer for preventing the distally facing surface <NUM> of the first implant component <NUM> to be damaged. An assembly adapter <NUM> made of a polymer also has the advantage that a relative rotation between the assembly adapter <NUM> and the first implant component <NUM> is unlikely to have an adverse effect on the distally facing surface of the first implant component <NUM>.

Once the first implant component <NUM> is moved distally beyond the proximal ends of the retaining elements <NUM> and abuts the contact surface <NUM> of the assembly adapter <NUM>, a user may rotate the transmission rod <NUM> about the longitudinal axis L in order to cause a movement of the actuation member <NUM> in the distal direction relative to the transmission rod <NUM> due to the threaded engagement of the actuation threads <NUM>, <NUM>.

As described above, this in turn results in the gliding surfaces <NUM> of the retaining elements <NUM> gliding proximally along the slanted actuation surfaces <NUM> of the actuation members distally tapered portion <NUM> so that the distal ends of the retaining elements <NUM> move away from each other in a direction perpendicular to the longitudinal axis L. Accordingly, the proximal ends of the a retaining elements <NUM> move towards each other due to the pivotal support of the retaining elements <NUM> about the rotation axes <NUM> of the base member <NUM>. This movement of the retaining elements' proximal ends makes the proximal retaining sections <NUM> close around a section of the first implant component <NUM>.

At the end of this movement, the distally facing retaining surfaces <NUM> of the retaining elements <NUM> are facing and support a proximally facing surface of the first implant component <NUM>, and the tool <NUM> has assumed its retaining position (see <FIG>). As shown in <FIG>, the first implant component <NUM> is now retained between the distally facing retaining surfaces <NUM> of the retaining elements <NUM> and the proximally facing contact surface <NUM> of the assembly adapter <NUM>. The clamping force exerted between the distally facing retaining surfaces <NUM> and the contact surface <NUM> is adjusted by turning the transmission rod <NUM>.

Consequently, the tool <NUM> is configured to move from the standby position to the retaining position so that the proximal retaining sections <NUM> of the retaining elements <NUM> enclose the first implant component <NUM> before the contact surface <NUM> and the distally facing retaining surfaces <NUM> exert a clamping force to the first implant component <NUM>.

In particular the threaded engagement between the transmission rod <NUM> and the actuation member <NUM>, the interaction between the slanted actuation surfaces <NUM> of the distally tapered portion <NUM> and the gliding surfaces <NUM> of the retaining elements <NUM>, the location of the rotation axes <NUM> along the retaining elements <NUM> and/or the distance between the contact surface <NUM> and the distally facing retaining surfaces <NUM> along the longitudinal axis L may be configured to enhance this functionality of the tool <NUM> by adjusting the transmission ratios between these components of the tool <NUM>.

As already mentioned above, the first implant component <NUM> may also comprise a retaining recess <NUM> for receiving a proximal retaining section <NUM> of a retaining element <NUM>. This prevents an unintended rotation of the first implant component <NUM> relative to the tool <NUM>.

Further, releasing the first implant component <NUM> from the tool <NUM> may be achieved by actuating the tool <NUM> in the reverse direction.

The first implant component <NUM> includes a first connecting portion <NUM> and the second implant component <NUM> includes a corresponding second connecting portion <NUM> for attaching the first implant component <NUM> and the second implant component <NUM> to each other. Preferably, the connecting portions <NUM> and <NUM> are configured as a tapered connection, in particular a self-locking tapered connection.

In particular in case of a tapered connection, the first implant component <NUM> and the second implant component <NUM> are assembled to each other using an impact force applied to the impact face <NUM> of the force transmission structure <NUM> and transmitted via the transmission rod <NUM> and the assembly adapter <NUM> to the first implant component <NUM>. As a result, the first implant component <NUM> moves towards the second implant component <NUM>.

After mounting the first implant component <NUM> to the second implant component <NUM>, the implant components are preferably secured to each other using an assembly screw <NUM>. As shown in <FIG>, the assembly screw <NUM> is preferably fastened using a fastening tool <NUM> that is inserted into the through hole <NUM> of the force transmission structure <NUM> (i.e. the transmission rod <NUM> and the assembly adapter <NUM>) and engages the head of the assembly screw <NUM>. Thus, the implant components <NUM>, <NUM> may be secured to each other more easily due to being guided by the tool <NUM>.

For securing the first implant component <NUM> to the second implant component <NUM> by an assembly screw <NUM>, the first implant component <NUM> comprises a through hole <NUM>. The through hole <NUM> includes a screw seat 3a for engaging the head 9a of the assembly screw <NUM>.

At a proximal portion 9b, the assembly screw <NUM> includes an outer thread for engaging and inner thread of a threaded hole <NUM> included in the second implant component <NUM>. The through hole <NUM> as well as the threaded hole <NUM> (e. a through hole with a threaded portion) are extending through the respective implant component <NUM>, <NUM> in a proximal-distal direction (in particular along the longitudinal axis L).

For securing the first and second implant components <NUM>, <NUM>, the assembly screw <NUM> is fastened by its threaded engagement with the threaded hole <NUM> of the second implant component <NUM> until the head 9a of the assembly screw <NUM> interacts with the screw seat 3a of the through hole <NUM> of the first implant component <NUM>. This secures the first implant component <NUM> to the second implant component <NUM> against unintended loosening.

Preferably, the screw seat 3a is formed by and at a distal end of an inner thread within the through hole <NUM> of the first implant component <NUM>. The inner thread of the through hole <NUM> is even more preferably formed in an opposite direction in relation to the thread of the threaded hole <NUM> of the second implant component <NUM> (i. right hand thread and left hand thread or vice versa).

As described above, the head 9a of the assembly screw <NUM> may have an outer thread for engaging the inner thread of the through hole <NUM>. Accordingly, the assembly screw <NUM> may be preassembled to the first implant <NUM> component by screwing the assembly screw <NUM> past the inner thread of the through hole <NUM>.

Since the inner thread of the through hole <NUM> is formed in the opposite direction relative to the threaded hole <NUM> and the outer thread at the proximal end of the assembly screw <NUM>, the head of the assembly screw <NUM> does not engage the inner thread of the through hole <NUM> so that the inner thread of the through hole <NUM> acts as a screw seat 3a.

As will be explained in the following under reference to <FIG>, the assembly screw <NUM> further allows for an easy disassembly of the first and second implant components <NUM> and <NUM>.

Before disassembly, the assembly screw <NUM> is unfastened, preferably until it disengages the threaded hole <NUM> of the second implant component <NUM>. In this state, the assembly screw <NUM> rests proximally in relation to the second connecting portion at the distal end of the threaded hole <NUM> (i. the threaded hole <NUM> acts as a screw seat for the threaded tip portion 9b of the assembly screw <NUM>).

For disassembly, the tool <NUM> engages the first implant component <NUM> as described above by a user turning the transmission rod <NUM> of the force transmission structure <NUM>. In contrast to an assembly using an assembly adapter <NUM>, for disassembly a disassembly adapter <NUM> is employed.

As illustrated in <FIG>, the disassembly adapter <NUM> is also mounted to the proximal end of the transmission rod <NUM>. In contrast to the assembly adapter <NUM> described above, the contact surface <NUM> of the disassembly adapter <NUM> does not interact with the first implant component but instead with the head 9a of the assembly screw <NUM> and via the proximal portion 9b of the assembly screw <NUM> with the second implant component <NUM>.

In particular, the contact surface <NUM> of the disassembly adapter <NUM> abuts the head of the assembly screw <NUM> that has previously been unscrewed from the threaded hole <NUM> of the second implant component <NUM>. Thus, in the retaining position, the first implant component <NUM> is clamped between the distally facing retaining surfaces <NUM> of the retaining elements <NUM> and the assembly screw <NUM>. As a result, the clamping force acts on the first connecting portion <NUM> of the first implant component <NUM> and the second connecting portion <NUM> of the second implant component <NUM> as a force separating these two implant components.

This interaction is used for disassembling the first implant component <NUM> from the second implant component <NUM>, i.e. for releasing the connection between the first connecting portion <NUM> and the second connecting portion <NUM>. This is achieved by actuating (i. turning) the transmission rod <NUM> further after the retaining position has been assumed so that the actuation member <NUM> moves further distally.

As can be appreciated from <FIG>, the further movement of the actuation member <NUM> in the distal direction causes the retaining elements <NUM> to move in the same direction. More specifically, since the proximal retaining sections <NUM> of the retaining elements <NUM> are prevented from moving further towards each other due to the first implant component <NUM> being interposed between the proximal retaining sections <NUM>, the gliding surfaces <NUM> are not able to continue their movement along the slanted actuation surface <NUM> of the actuation member's distally tapered portion <NUM>. Consequently, the retaining elements <NUM> and the base member <NUM> start moving distally relative to the transmission rod <NUM>. For this relative movement, the through hole in the base member <NUM> is configured to let the transmission rod <NUM> move and rotate freely, as has been previously described above.

This movement of the retaining elements <NUM> in a distal direction results in a pull-off motion of the first implant component <NUM> caused by the contact of the first implant component with the distally facing retaining surfaces <NUM>. Accordingly, disassembly of the first implant component <NUM> from the second implant component <NUM> is caused by a defined and controlled movement instead of an impact force.

Claim 1:
A tool (<NUM>) for assembling and disassembling a first implant component (<NUM>) and a second implant component (<NUM>), the tool comprising:
a proximal end (<NUM>), a distal end (<NUM>), and a longitudinal axis;
an elongated force transmission structure (<NUM>) for transmitting a force in a direction along the longitudinal axis (L), the force transmission structure including a proximally facing contact surface (<NUM>);
two elongated retaining elements (<NUM>), each retaining element having a distally facing retaining surface (<NUM>) at a proximal end thereof; and
an actuation mechanism (<NUM>), wherein the actuation mechanism is operable to move the retaining elements between a standby position and a retaining position, wherein in the retaining position the proximal ends of the retaining elements are closer to each other than in the standby position; and
wherein the actuation mechanism (<NUM>) further comprises an actuation member (<NUM>), the actuation member being arranged between distal ends of the retaining elements (<NUM>); and
characterized in that the actuation member includes a distally tapered portion (<NUM>), wherein the distal ends of the retaining elements are in contact with a slanted surface (<NUM>) of the distally tapered portion, such that a further actuation of the actuation mechanism (<NUM>) after assuming the retaining position causes a relative movement of the distally facing retaining surfaces (<NUM>) in relation to the contact surface (<NUM>) in a distal direction.