Patent Description:
Hip replacement is a surgical procedure in which the hip joint is replaced by artificial joint components, also referred to generally as prostheses or implants. Total replacement of the hip joint involves installing an acetabular cup implant in the acetabulum of a patient and installing a prosthetic in the femur of the patient. Joint replacement surgery can also be performed in other joints, such as the shoulder.

For hip replacement surgery, the prosthetic typically includes a femoral stem, which is received in the medullary canal of the femur, and a femoral head having a bearing surface which is received in the acetabulum or acetabular cup implant. The prosthetic typically also includes a femoral neck which extends between a proximal end of the stem and the head.

Successful hip replacement surgery requires correct positioning and alignment of the acetabular cup implant as well as the prosthetic itself. Misalignment and/or the selection of an inappropriately sized acetabular cup implant and/or the prosthetic may result in restricted movement of the prosthetic and/or accelerated wear and tear of the bearing surfaces of the acetabular cup implant and the bearing surface of the head. Various factors are involved in achieving this correct positioning and alignment. At least some of these factors relate to the neck of the prosthetic. These factors may include, for instance, the length of the neck, and an angular orientation (offset) of the neck relative to the stem. Trialling may be used during such orthopaedic procedures in order to help assess the patient's needs.

Trialling can be used during primary or complex primary and revision surgeries. During trialling, the surgeon uses trial components, rather than the actual implants, to help assess whether any changes might be made to bone cuts and/or soft tissues and/or the implants originally planned to be used. It can be more efficient to utilise a bone canal preparation instrument as one of these components.

During a primary hip or shoulder arthroplasty procedure, various sizes of broach or other bone canal preparation instruments may be used to prepare the medullary canal of the femur or humerus. Once the bone canal preparation instrument is inserted into the bone, a trial neck and trial head may also be attached to the bone canal preparation instrument, in order to evaluate whether a prosthetic having a neck and head of that type (e.g. in terms of the size and offset of the neck) would be appropriate for the patient.

Conventionally trial necks are connected to the spigot of the bone canal preparation instrument by the use of an O-ring. The O-ring forms an interference fit or friction fit when it arranged between the spigot and the internal surface of the trial neck.

After the surgeon is satisfied that the chosen combination of bone canal preparation instrument, trial neck and trial head are correctly positioned and aligned, they may be removed and replaced with the implant itself.

Occasionally revision arthroplasty surgery may need to be performed on a patient. In such a revision surgery, the previously implanted prosthesis is surgically removed, and a replacement prosthesis is implanted. In some revision surgeries, all of the components of the previously implanted hip prosthesis, including, for example, the femoral stem, neck component, and the acetabular cup, may be surgically removed. In other revision surgeries, only part of the previously implanted prosthesis may be removed and replaced.

<CIT> describes a trial neck and a method for trialling a neck of an orthopaedic implant in a hip replacement procedure. The method includes inserting a broach into a medullary canal of a femur of a patient. The method also includes connecting a distal end of a trial neck to a proximal end of the broach. The trial neck includes a proximal end connectable to a trial head. The trial neck further includes a body portion extending along a neck axis of the trial neck between the distal end and the proximal end. The trial neck also includes also includes a resilient retaining member configured to engage a surface of the broach when the trial neck is connected to the broach, for inhibiting removal of the trial neck from the broach. The method further includes engaging the resilient retaining member with the surface of the broach.

Aspects of the present invention are set out in the accompanying independent and dependent claims. Combinations of features from the dependent claims may be combined with features of the independent claims as appropriate and not merely as explicitly set out in the claims.

According to a first aspect of this invention there is provided a trial neck for releasable attachment to a bone canal preparation instrument, the trial neck comprising:.

wherein in the clamping configuration, the pair of arms of the elongate neck part are pinched together to cause an inner wall of the bore to urge against the bone canal preparation instrument to retain the proximal end of the bone canal preparation instrument within the bore.

The pinching together of the pair of arms can narrow and/or distort the bore so that it can grip the proximal end of the bone canal preparation instrument to provide a secure attachment of the trial neck to the bone canal preparation instrument.

The clamping mechanism may allow the trial neck to be attached to a bone canal preparation instrument in a variety of orientations e.g. around a longitudinal axis of the bone canal preparation instrument.

The pair of arms may extend from the elongate neck part into the body portion, and the bore for receiving the proximal end of the bone canal preparation instrument may pass through the pair of arms.

The bore may be defined by a bore annulus and the pair of arms may be positioned such that an arm is located on either side of a break in the bore annulus. The break in the bore annulus promotes distortion of the bore when the pair of arms are pinched together.

The pair of arms may comprise a superiorly located arm and an inferiorly located arm.

The trial neck may further include a partially threaded actuator bore which extends through the pair of arms. The partially threaded actuator bore may be arranged such that one of the superior or inferior arm may comprise an unthreaded portion of the actuator bore, and the other of the superior or inferior arm comprises a threaded portion of the actuator bore. The actuator may comprise a threaded actuation member extending within the partially threaded actuator bore. The threaded actuator can provide a convenient way of operating the clamping mechanism. Further, the threaded actuator can allow fine adjustments to be made to the size of the bore for receiving the proximal end of the bone canal preparation instrument.

The actuator bore may extend substantially parallel to the bore for receiving the proximal end of the bone canal preparation instrument.

The elongate neck part may also comprise a proximal end; a distal end; and a neck axis extending between the proximal and distal ends. The actuator bore may extend from the proximal end to the distal end of the elongate neck part such that the actuator bore extends substantially parallel to a neck axis. This can allow the surgeon to have improved accessibility to the actuator bore when the actuator bore extends from the proximal end of the elongate neck part.

The elongate neck part may also comprise a proximal part, a distal part, and a neck axis extending between the proximal and distal parts. The distal part may comprise the pair of arms. The threaded actuator bore and threaded actuation member may be substantially parallel to the neck axis. The proximal part may be detachable from the distal part, wherein attachment of the proximal part onto the distal part causes the pair of arms of the elongate neck part to be pinched together to cause an inner wall of the bore to urge against the bone canal preparation instrument to retain the proximal end of the bone canal preparation instrument within the bore. This can allow the surgeon to have improved accessibility to the actuator bore when the actuator bore extends from the proximal end of the elongate neck part.

The actuator may comprise a trial head having a bore for connection to the trial neck, wherein attachment of the trial head over the proximal end of the elongate neck part causes the pair of arms of the elongate neck part to be pinched together to cause an inner wall of the bore to urge against the bone canal preparation instrument to retain the proximal end of the bone canal preparation instrument within the bore. This can reduce the number of parts needed to form the trial since there is no need for a separate actuation member.

The pair of arms may include a recess for engagement with a corresponding projection inside the bore of the trial head, wherein the recess has a variable depth along its length, and wherein rotation of the projection within the recess causes the pair of arms of the elongate neck part to be pinched together to cause an inner wall of the bore to urge against the bone canal preparation instrument to retain the proximal end of the bone canal preparation instrument within the bore. The recess allows the user to adjust the level of pinching by the arms, and so adjust the size of the bore for receiving the bone canal preparation instrument. This can reduce the number of parts needed to form the trial since there is no need for a separate actuation member. The rotation of projections within the recess is a convenient way of operating the clamping mechanism and using the trial head as the actuator can provide for an easily accessible mechanism for a surgeon.

wherein the proximal part of the elongate neck part is detachable from the distal part, and wherein attachment of the proximal part to the distal part causes the pair of arms to pinch together to cause an inner wall of the bore to urge against the bone canal preparation instrument to retain the proximal end of the bone canal preparation instrument within the bore.

This can provide increased leverage, because the arms are pinched together at the proximal end of the arms.

The pair of arms may be threaded at a proximal end of the distal part for connection to a corresponding thread on an inner wall of the actuator bore of the proximal part. This can provide for a secure connection between the distal and proximal parts.

The proximal end of the distal part may comprise at least one protrusion on an outer surface of the pair of arms. At least one protrusion may extend from an inner wall of the actuator bore. When assembled, a distal surface of the at least one protrusion on the proximal end of the distal part may abut a proximal surface of the at least one protrusion on the proximal part. Attachment of the proximal part to the distal part may cause the pair of arms to pinch together to cause an inner wall of the bore to urge against the bone canal preparation instrument to retain the proximal end of the bone canal preparation instrument within the bore. This mechanism can allow the user to quickly attach the proximal part to the distal part whilst activating the clamping mechanism.

The pair of arms may comprise an anteriorly located arm and a posteriorly located arm.

According to another aspect of the invention, there is provided a surgical kit comprising:.

The surgical kit may further comprise a trial head having a bore for receiving the proximal end of the elongate neck part to releasably attach the trial head to the trial neck. The surgical kit may further comprise a prosthetic stem component.

According to a further aspect of this disclosure, there is provided a method of attaching a trial neck to a bone canal preparation instrument, the trial neck comprising:.

the method comprising:
inserting the proximal end of the bone canal preparation instrument into the bore; and
using the actuator to pinch the pair of arms of the elongate neck part together to cause an inner wall of the bore to urge against the bone canal preparation instrument.

The pinching together of the pair of arms narrows the bore to provide a secure attachment of the trial neck onto the bone canal preparation instrument without the need for the bone canal preparation instrument to be at a specific angle or position. The trial neck can therefore be attached to a bone canal preparation instrument in a variety of orientations.

The pair of arms of the trial neck may extend from the elongate neck part into the body portion. The bore for receiving the proximal end of the bone canal preparation instrument may pass through the pair of arms.

The bore may be defined by a bore annulus and the pair of arms may be positioned such that an arm is located on either side of a break in the bore annulus. The break in the bore annulus promotes distortion of the bore when the pair of arms are pinched together. This allows retention of the proximal end of the reamer by both axial tension and torsional forces.

The break in the bore annulus may be transverse to the bore axis, or may be a longitudinal break, extending the length of the bore (parallel to the bore axis). A transverse break promotes distortion of the bore and provides axial tension against the proximal end of the reamer. A longitudinal break promotes distortion of the bore and provides torsional tension against the proximal end of the reamer. Both the transverse and longitudinal beaks provide a degree of axial tension and torsional forces.

A partially threaded actuator bore may extend through the pair of arms. The partially threaded actuator bore may be arranged such that one of the pair of arms may include a threaded portion of the actuator bore, while the other arm may include an un-threaded portion of the actuator bore. The actuator may comprise a threaded actuation member extending within the threaded actuator bore. The threaded actuator can provide a convenient way of operating the clamping mechanism. Further, the threaded actuator can allow fine adjustments to be made to the size of the bore for receiving the proximal end of the bone canal preparation instrument.

The actuator may comprise a trial head having a bore for connection to the trial neck. The method may further comprise placing the trial head over the proximal end of the elongate neck part to pinch together the pair of arms of the elongate neck part, causing an inner wall of the bore to urge against the bone canal preparation instrument to retain the proximal end of the bone canal preparation instrument within the bore.

The pair of arms may include a recess for engagement with a corresponding projection inside the bore of the trial head. The recess may have a variable depth along its length. The method may further comprise rotating the trial head to rotate the projection within the recess to cause the pair of arms of the elongate neck part to pinch together to cause an inner wall of the bore to urge against the bone canal preparation instrument to retain the proximal end of the bone canal preparation instrument within the bore.

The pair of arms may be threaded at a proximal end of the distal part for connection to a corresponding thread on an inner wall of the actuator bore of the proximal part.

The proximal end of the distal part may comprise at least one protrusion on an outer surface of the pair of arms. At least one protrusion may extend from an inner wall of the actuator bore. The method may further comprise attaching the proximal part to the distal part to position a distal surface of the at least one protrusion on the proximal end of the distal part in abutment with a proximal surface of the at least one protrusion on the proximal part to cause the pair of arms to pinch together to cause an inner wall of the bore to urge against the bone canal preparation instrument to retain the proximal end of the bone canal preparation instrument within the bore.

Embodiments of this disclosure will be described hereinafter, by way of example only, with reference to the accompanying drawings in which like reference signs relate to like elements and in which:.

Embodiments of this disclosure are described in the following with reference to the accompanying drawings.

Referring to <FIG> there is shown a trial neck. The trial neck <NUM> has a body portion <NUM>. The body portion <NUM> includes a bore <NUM>. The bore <NUM> may be a blind bore (closed at its proximal end), although in the embodiments shown in the Figures it is an open bore, which passes completely through the body portion <NUM>. The bore <NUM> can receive the proximal end of a bone canal preparation instrument, for attaching the bone canal preparation instrument to the trial neck <NUM>.

The bone canal preparation instrument may, for example, be a trial stem, or a cutting instrument such as a reamer or a broach. In the following description, the bone canal preparation instrument comprises a reamer <NUM>, but it will be appreciated that in other examples, the bone canal preparation instrument may be one of the other instruments noted above. An exemplary reamer <NUM> is shown in <FIG>.

The reamer <NUM> itself may be in the form of an elongate shaft and may have a cutting surface located distally. The reamer <NUM> has a proximal end located proximally with respect to the cutting surface. The proximal end may be substantially cylindrical, with a circular cross section, although this is not essential. The proximal end may be inserted into the bore <NUM> of the trial neck <NUM> for attaching the reamer <NUM> to the trial neck <NUM>, as will be described in more detail below.

As shown in <FIG>, the trial neck <NUM> also has an elongate neck part <NUM>. The elongate neck part <NUM> extends from the body portion <NUM>. The elongate neck part <NUM> has a proximal end <NUM> and a distal end <NUM> and a neck axis <NUM> which extends between the proximal <NUM> and distal ends <NUM>.

A proximal end <NUM> of the elongate neck part <NUM> may be configured to be attached to a trial head <NUM>. In other examples, the trial head <NUM> may be integral with the trial neck <NUM> (not shown).

The elongate neck part <NUM> includes a pair of arms <NUM> extending from the body portion <NUM>. The pair of arms extend from the elongate neck part <NUM> and around the bore <NUM> to join with the body portion <NUM> such that the bore <NUM> for receiving the proximal end of the reamer <NUM> may pass through the pair of arms <NUM>.

The bore <NUM> is defined by a bore annulus. The bore annulus is broken, such that there is a gap <NUM> in the wall of the bore which may extend the length of the bore <NUM>. The pair of arms are positioned such that one arm is located on either side of a break in the bore annulus. The break in the bore annulus promotes distortion of the bore <NUM> when the pair of arms <NUM> are pinched together.

The trial neck <NUM> comprises a clamping mechanism <NUM> for attaching the proximal end of the reamer <NUM> to the trial neck <NUM>. The clamping mechanism <NUM> is a live spring formed by the body portion <NUM> and the pair of arms <NUM> of the elongate neck part <NUM>. The clamping mechanism <NUM> can be used to lock the proximal end of the reamer <NUM> within the bore <NUM>, so as to prevent movement of the reamer <NUM> with respect to the trial neck <NUM> and/or inadvertent decoupling of the trial neck <NUM> from the reamer <NUM>.

The trial neck <NUM> also comprises an actuator <NUM> for moving the clamping mechanism <NUM> between a clamping configuration and a non-clamping configuration. In the clamping configuration, the pair of arms <NUM> of the elongate neck part <NUM> are pinched together to cause an inner wall <NUM> of the bore <NUM> to urge against the reamer <NUM> to retain the proximal end of the reamer <NUM> within the bore <NUM>.

Specific features of the different embodiments of this disclosure will now be discussed separately and in more detail, in which like features are indicated with like reference numerals.

In the embodiment shown in <FIG>, the pair of arms <NUM> includes a superior arm <NUM> and an inferior arm <NUM>. The pair of arms <NUM> are positioned such that one arm is located on either side of the gap <NUM> in the bore annulus. As shown in <FIG>, the gap <NUM> can be transverse to the bore axis.

As may be appreciated from <FIG>, the actuator <NUM> can be a threaded actuation member which causes the clamping mechanism <NUM> to move into the clamping configuration as the actuator <NUM> is threaded through the actuator bore <NUM>. The actuator bore <NUM> may extend through the pair of arms <NUM>. The actuator bore <NUM> may include a corresponding thread for cooperation with the thread of the actuator <NUM>. The actuator bore <NUM> may be partially threaded and may be arranged such that the inferior arm <NUM> may include a threaded portion of the actuator bore <NUM>, while the superior arm <NUM> may include an unthreaded portion of the actuator bore <NUM>. Alternatively, the superior arm <NUM> may include a threaded portion of the actuator bore <NUM>, while the inferior arm <NUM> may include an unthreaded portion of the actuator bore <NUM>. A proximal end of the actuator <NUM> may comprise a connection feature for connecting a corresponding connection feature of a tool to the actuator <NUM> for actuating the actuator <NUM>.

As shown in <FIG>, the actuator <NUM> may be a screw.

The actuator bore <NUM> may extend substantially parallel to the bore <NUM> for receiving the proximal end of the reamer <NUM>, as shown in <FIG>. Alternatively, the actuator bore <NUM> may extend from the proximal end <NUM> to the distal end <NUM> of the elongate neck part <NUM> such that the actuator bore <NUM> extends substantially parallel to a neck axis <NUM>. This is shown for example in <FIG> and <FIG>. In this embodiment, the proximal part <NUM> of the elongate neck part <NUM> may be detachable from the distal part <NUM>. Alternatively, the elongate neck part <NUM> may be a single piece with the actuator bore <NUM> extending substantially parallel to the neck axis <NUM> in the same way.

In <FIG>, the proximal part <NUM> is shown in connection with the distal part <NUM> via the actuator <NUM>. Rotation of the actuator <NUM> within the actuator bore <NUM> (for example using a tool) can cause the actuator to move back and forth within the actuator bore <NUM>. As the actuator <NUM> is threaded through the partially threaded actuator bore <NUM>, it pulls the inferior arm <NUM> towards the superior arm <NUM> which causes the clamping mechanism <NUM> to move from a non-clamping configuration to a clamping configuration. As previously described, this movement causes the pair of arms <NUM> of the elongate neck part <NUM> to pinch together, causing the inner wall <NUM> of the bore <NUM> to urge against the reamer <NUM> thus retaining the proximal end of the reamer <NUM> within the bore <NUM>. <FIG> shows the proximal part <NUM> and the actuator <NUM> detached from the distal part <NUM> of the elongate neck part <NUM>.

In the embodiments shown in <FIG>, the actuator <NUM> is a trial head <NUM>. The proximal end <NUM> of the elongate neck part <NUM> may include connection feature(s) for connection to complementary features on the trial head <NUM>. The embodiments shown in <FIG> include a superior arm <NUM> and an inferior arm <NUM>. The pair of arms <NUM> are positioned such that one arm is located on either side of the gap <NUM> in the bore annulus. The gap <NUM> is transverse to the bore axis.

The trial head <NUM> of <FIG> includes a trial head bore <NUM> which may have a projection <NUM> located on the inner wall of the bore <NUM>. A corresponding recess <NUM> may be located on the proximal part <NUM> of the elongate neck part <NUM>. In this embodiment, the proximal end <NUM> of the elongate neck part <NUM> may be formed from a superior arm <NUM> and an inferior arm <NUM>. As such each of the superior arm <NUM> and the inferior arm <NUM> may have a projection <NUM> for connection with a corresponding recess <NUM> in the inner bore <NUM> of the trial head <NUM>. Alternatively, the recess <NUM> could be located on the inner wall of the trial head bore <NUM>, and the projection <NUM> could be located on the proximal part <NUM> of the elongate neck part <NUM>. There may be a single projection <NUM> or two or more projections <NUM>.

<FIG> shows the recess <NUM> of the inferior arm <NUM> in more detail.

The effect of the clamping mechanism <NUM> can be seen by comparing <FIG> and <FIG> shows the trial neck <NUM> in the non-clamping configuration, without the trial head <NUM> attached. <FIG> shows the trial neck <NUM> in the clamping configuration, with the trial head <NUM> attached. As the trial head <NUM> is connected to the proximal end <NUM> of the elongate neck part <NUM>, it pinches the inferior arm <NUM> and superior arm <NUM> together, decreasing the space between the arms. This causes the clamping mechanism <NUM> to move from a non-clamping configuration to a clamping configuration because as the arms are pinched together, the movement causes the inner wall <NUM> of the bore <NUM> to deform, reducing the size of the bore <NUM>.

In one embodiment, the trial head <NUM> may be attached to the trial neck <NUM> by pinching together the superior and inferior arms and inserting the proximal end <NUM> of the elongate neck part <NUM> into the trial head bore <NUM> until the projection(s) <NUM> mates with the recess <NUM> to hold the trial head <NUM> in place.

In another embodiment, the recess <NUM> may have a variable depth along its length such that rotation of the projection(s) <NUM> within the recess <NUM> causes the pair of arms <NUM> of the elongate neck part <NUM> to be pinched together to a greater or lesser amount relative to the depth of the recess <NUM>. The projection(s) <NUM> can be rotated within the recess <NUM> by rotating the trial head <NUM> once the projection(s) have mated with the recess <NUM>.

<FIG> shows a different embodiment having an anterior arm <NUM> and a posterior arm <NUM>. As with previously described embodiments, the distal end <NUM> of the pair of arms <NUM> extend around the bore <NUM> to join with the body portion <NUM> such that the bore <NUM> for receiving the proximal end of the reamer <NUM> passes through the pair of arms <NUM>. The pair of arms <NUM> are positioned such that one arm is located on either side of the gap <NUM> in the bore annulus. In this embodiment, the gap <NUM> is a longitudinal gap <NUM>, extending the length of the bore (parallel to the bore axis).

A head attachment portion <NUM>, for attachment to a trial head (not shown) forms the proximal part <NUM> of the elongate neck part <NUM>. The connection of the proximal part <NUM> with the distal part <NUM> causes the clamping mechanism <NUM> to move from a non-clamping configuration to a clamping configuration. As previously described, this movement causes the inner wall <NUM> of the bore <NUM> to urge against the reamer <NUM> thus retaining the proximal end of the reamer <NUM> within the bore <NUM>.

As shown in <FIG>, the proximal end <NUM> of the distal part <NUM> comprises a threaded actuator <NUM> in the form of a head attachment portion <NUM> of the elongate neck part <NUM>. The threaded actuator <NUM> includes threads on the outer surface of the anterior and posterior arms <NUM>, <NUM>. The head attachment portion <NUM> comprises an actuator bore <NUM> at its distal end. The actuator bore may contain a corresponding thread on its inner wall <NUM>, for mating with the threaded actuator <NUM> on the pair of arms <NUM>. The proximal end <NUM> of the distal part <NUM> can be inserted into the actuator bore of the proximal part <NUM>, and rotation of the head attachment portion <NUM> causes the clamping mechanism <NUM> to move from a non-clamping configuration to a clamping configuration due to the engagement of the threaded components.

An alternative embodiment is shown in <FIG>, this embodiment also includes an anterior arm <NUM> and a posterior arm <NUM>. As with previously described embodiments, the distal end <NUM> of the pair of arms <NUM> extend around the bore <NUM> to join with the body portion <NUM> such that the bore <NUM> for receiving the proximal end of the reamer <NUM> may pass through the pair of arms <NUM>. The pair of arms <NUM> and the body portion <NUM> form the distal part <NUM> of the trial neck <NUM>. A head attachment portion <NUM>, for attachment to a trial head (not shown) forms the proximal part <NUM> of the elongate neck part <NUM>.

In the embodiment of <FIG>, the pair of arms <NUM> are positioned such that one arm is located on either side of the gap <NUM>, which extends the length of the bore (parallel to the bore axis).

As shown in <FIG>, the proximal end <NUM> of the distal part <NUM> comprises at least one protrusion <NUM> on an outer surface of the pair of arms <NUM>. The head attachment portion <NUM> comprises an actuator bore <NUM> at its distal end. At least one protrusion <NUM> may also extend from an inner wall <NUM> of the actuator bore <NUM>. When assembled, a distal surface <NUM> of the at least one protrusion <NUM> on the proximal end <NUM> of the distal part <NUM> abuts a proximal surface <NUM> of the at least one protrusion <NUM> on the proximal part <NUM>. As such, attachment of the proximal part <NUM> to the distal part <NUM> causes the pair of arms <NUM> to pinch together to move the clamping mechanism <NUM> from a non-clamping configuration to a clamping configuration. As previously described, this movement causes the inner wall <NUM> of the bore <NUM> to urge against the reamer <NUM> thus retaining the proximal end of the reamer <NUM> within the bore <NUM>.

According to an embodiment of this disclosure, there may be provided a surgical kit comprising a trial neck (for example a trial neck <NUM> of the kind described above) and a reamer <NUM>. The surgical kit may further comprise a trial head <NUM> having a bore <NUM> for receiving the proximal end <NUM> of the elongate neck part <NUM> to releasably attach the trial head <NUM> to the trial neck <NUM>. It is envisaged that the kit may include further components (e.g. one or more differently sized trial necks of the kind described above, one or more different kinds of reamer <NUM>, one or more trial heads, and/or any other components). An exemplary reamer <NUM> is shown in <FIG> and <FIG>. Note that the geometry of the proximal end of the reamer <NUM> illustrates one of many examples which may be used with the neck trial <NUM> of the present disclosure.

<FIG> shows an exemplary femoral stem <NUM> prosthetic component which may be inserted following preparation of the femur using any embodiments listed above.

According to a further embodiment of this disclosure, there may be provided a method of attaching a trial neck (for example a trial neck <NUM> of the kind described above) to a reamer <NUM>, as shown in the flow chart of <FIG>.

The method may include a step <NUM> of inserting the proximal end of a reamer <NUM> into the bore <NUM> of the trial neck <NUM>, as shown in <FIG>.

The method may also include connecting a tool to a connection feature on the actuator <NUM> for actuating the actuator <NUM>. For example, a tool such as a screwdriver may be used when the actuator <NUM> is a screw.

The method may include a step <NUM> of using the actuator <NUM> to pinch the pair of arms <NUM> of the elongate neck part <NUM> together to cause an inner wall <NUM> of the bore <NUM> to urge against the reamer <NUM>.

In a subsequent step <NUM>, the user can check whether the inner wall <NUM> of the bore <NUM> is urged against the reamer <NUM>. It may be necessary to repeat step <NUM> until the actuator has sufficiently pinched together the pair of arms <NUM> enough to urge the inner wall <NUM> of the bore <NUM> against the reamer <NUM> so that the reamer <NUM> is attached to the trial neck <NUM>.

The actuator may comprise a trial head <NUM>. As such, step <NUM> of the method may include placing a trial head <NUM> over the proximal end <NUM> of the elongate neck part <NUM> to pinch together the pair of arms <NUM> of the elongate neck part <NUM>. The method may include rotating the trial head <NUM> to rotate a projection <NUM> within a recess <NUM> to cause the pair of arms <NUM> of the elongate neck part <NUM> to pinch together.

The actuator may comprise a proximal part <NUM>. As such, step <NUM> of the method may include attaching a proximal part <NUM> to a distal part <NUM> to position a distal surface <NUM> of at least one protrusion <NUM> on the proximal end <NUM> of the distal part <NUM> in abutment with a proximal surface <NUM> of at least one protrusion <NUM> on the proximal part <NUM> to cause the pair of arms <NUM> to pinch together.

Accordingly, there has been described a trial neck for hip surgery and a method of attaching a trial neck to a bone canal preparation instrument. The trial neck includes a body portion having a bore for receiving a proximal end of the bone canal preparation instrument. The trial neck also includes an elongate neck part comprising a pair of arms extending from the body portion. The trial neck further includes a clamping mechanism comprising a live spring formed by the body portion and said pair of arms of the elongate neck part and an actuator, for moving the clamping mechanism between a clamping configuration and a non-clamping configuration. In the clamping configuration, the pair of arms of the elongate neck part are pinched together to cause an inner wall of the bore to urge against the bone canal preparation instrument to retain the proximal end of the bone canal preparation instrument within the bore.

Claim 1:
A trial neck (<NUM>) for releasable attachment to a bone canal preparation instrument, the trial neck comprising:
a body portion (<NUM>) having a bore (<NUM>) for receiving a proximal end of the bone canal preparation instrument (<NUM>);
an elongate neck part (<NUM>) comprising a pair of arms (<NUM>) extending from the body portion (<NUM>); and
a clamping mechanism (<NUM>) comprising a live spring formed by the body portion (<NUM>) and said pair of arms (<NUM>) of the elongate neck part; characterised in that the trial neck further comprises
an actuator (<NUM>), for moving the clamping mechanism (<NUM>) between a clamping configuration and a non-clamping configuration,
wherein in the clamping configuration, the pair of arms (<NUM>) of the elongate neck part are pinched together to cause an inner wall (<NUM>) of the bore to urge against the bone canal preparation instrument (<NUM>) to retain the proximal end of the bone canal preparation instrument within the bore (<NUM>).