Patent Application
20210267770
The present invention relates to systems and methods for correctly positioning an acetabular component in an acetabulum of a patient. Particularly although not exclusively embodiments of the present invention relate to an apparatus for aligning an acetabular component in a desired alignment prior to insertion of the acetabular component in the acetabulum. Also disclosed herein are systems which comprise an apparatus for inserting an acetabular component and a device for locating the acetabular component during the insertion operation. Aptly, the systems and apparatus of embodiments of the present invention may be suitable for use in combination with cemented and non-cemented acetabular components. Aptly, the system and apparatus described herein are for use in total hip replacement surgery.
Hip replacement is a surgical procedure in which the hip joint is replaced by a prosthetic implant. 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. A ball of the prosthetic is received in the acetabular cup implant.
Successful hip replacement surgery requires correct alignment and positioning of the acetabular cup implant. Misalignment of the acetabular component may result in dislocation, undesired wear and tear of the bearing surfaces of the implants and/or restricted movement of the prosthetic within the acetabulum.
Hip replacement surgery sometimes requires the fixation of the acetabular cup implant with cement in the acetabulum. Cement can escape from the acetabulum when the implant is being positioned.
There is a need to provide means to correctly align acetabular components within an acetabulum during surgery and also to avoid displacement of cement in cemented procedures.
Various aspects and embodiments of the present invention are described herein.
In a first aspect of the present invention, there is provided an apparatus for locating an acetabular component in an acetabulum of a patient, the apparatus comprising:
a. a proximal portion;
b. a distal portion; and
c. a connecting portion intermediate the proximal portion and the distal portion, wherein the connecting portion includes:
In certain embodiments, the acetabular component comprises a polar axis and the apparatus serves to orient the polar axis at a prescribed angle of inclination and a prescribed angle of anteversion.
In certain embodiments, when the patient is located in a supine or lateral position on an operating table, the patient having a long axis, the alignment surface is configured to be locatable at a predetermined angle with respect to the long axis of the patient so as to orient the polar axis at the prescribed angle of inclination.
In certain embodiments, the alignment surface comprises a plane and wherein the plane of the alignment surface is generally parallel to the coronal plane of the patient to represent an angle of anteversion of between 10° to 20° e.g. about 15°. In certain embodiments, the first branch portion comprises a first alignment surface configured to align the acetabular component in a first acetabulum of the patient and the second branch portion comprises a further alignment surface configured to align the acetabular component in a further acetabulum of the patient.
In certain embodiments, the apparatus serves to orient the acetabular component along an alignment axis in the acetabulum during surgery, wherein the alignment axis is an axis along which it is desirable to insert an acetabular component into the acetabulum during surgery.
In certain embodiments, the alignment axis extends at an angle of:
In certain embodiments, the alignment guide portion comprises a central region from which the first branch portion and the second branch portion extend at an acute angle to each other, the acute angle being in the range of from about 15° to about 60°. In certain embodiments, the acute angle is about 35° to about 45°. In certain embodiments, the acute angle is about 40°.
In certain embodiments, the first branch portion and the second branch portion are substantially symmetrical about a longitudinal axis of the alignment guide portion. In certain embodiments, the arm portion comprises a longitudinal axis and further wherein the longitudinal axis of the alignment guide portion and the longitudinal axis of the arm portion are generally orthogonal with respect to each other.
In certain embodiments, the proximal portion comprises a handle portion at a proximal end thereof. In certain embodiments, the distal portion comprises an insertion portion at a distal end thereof, wherein the insertion portion comprises a plate portion having a central protrusion.
In certain embodiments, the plate portion is generally circular. In certain embodiments, the central protrusion comprises a conical frustum. In certain embodiments, the apparatus is an integrally formed apparatus.
In certain embodiments, the apparatus further comprises a detachable introducer plate configured to be locatable in an acetabular component.
In certain embodiments, the apparatus is configured to locate a cemented acetabular component in the acetabulum of a patient.
In a further aspect of the present invention, there is provided a method of locating an acetabular component in an acetabulum of a patient, the method comprising:
In certain embodiments, the method further comprises locating a fixation material in the acetabulum of the patient prior to step (c).
In certain embodiments, the method comprises aligning the first branch region or the second branch region such that the plane of the respective alignment surface is generally parallel to the coronal plane of the patient, when the patient is positioned in an extended supine or lateral position. In certain embodiments, the method further comprises aligning the arm portion generally orthogonally to the longitudinal axis of the patient, when the patient is positioned in an extended supine or lateral position.
In certain embodiments, the method further comprises withdrawing the apparatus from the acetabulum once the acetabular component is located in a desired orientation in the acetabulum.
In certain embodiments, the method further comprises, prior to step (c), the steps of:
In a further aspect of the present invention there is provided a kit comprising the apparatus according to the first aspect of the present invention, and at least one acetabular component.
In certain embodiments, the acetabular component is a trial component or an acetabular prothesis. In certain embodiments, the kit further comprises a fixation material e.g. cement.
In a further aspect of the present invention there is provided a device for introducing an acetabular component into an acetabulum of a patient; the device comprising:
In certain embodiments, the at least one slit is configured to enable the upper portion to expand or contract in circumference upon application of pressure.
In certain embodiments, the upper portion comprises at least two slits. In certain embodiments, the upper portion is a truncated cylinder. In certain embodiments, the base portion comprises an outer annular rim portion.
In certain embodiments the device is an introducer plate.
In a further aspect of the present invention, there is provided a system comprising the apparatus according to the first aspect of the present invention and a device according to a further aspect of the present invention, wherein the central protrusion is configured to be locatable in the central aperture of the base portion and the cut-out region of the upper portion.
In a further aspect of the present invention there is provided a system for locating an acetabular component in an acetabulum of a patient, the system comprising:
a) an apparatus for introducing the acetabular component into the acetabulum, the apparatus comprising:
b) a device for supporting an acetabular component during the locating operation, the device comprising a base portion having a central aperture and a radially expandable upper portion having a lower surface which is at least partially connected to the base portion, the upper portion comprising at least one slit and a central cut-out region, wherein the cut-out region of the upper portion and the central aperture of the base portion are at least partially aligned.
In certain embodiments, the device is a device as described herein.
In certain embodiments, the distal portion of the apparatus comprises a plate for mounting the device. Particularly, the plate may comprise a protrusion locatable in the central cut-out position and the central aperture to secure the device to the apparatus. In some embodiments, the system further comprises an acetabular component locatable over the upper portion of the device such that a rim portion of the acetabular component abuts the base portion. The apparatus may be an apparatus according to a first aspect of the present invention or may be an introducer apparatus as described herein. In certain embodiments, the connecting portion comprises a lever element which is connected to the central protrusion.
Also included in the present invention is an apparatus for locating an acetabular component in an acetabulum of a patient, the apparatus comprising a proximal portion; a distal portion; and a connecting portion intermediate the proximal portion and the distal portion, wherein the connecting portion includes an arm portion connected to the distal portion and comprising a longitudinal axis; and an alignment guide portion extending between the distal portion and the arm portion, the alignment guide portion being integrally formed with the proximal portion and the distal portion and comprising a first branch portion and a second branch portion, and wherein the first branch portion and/or the second branch portion provides an alignment surface.
In a yet further aspect of the present invention there is provided an apparatus for introducing an acetabular component into an acetabulum of a patient, the apparatus comprising:
In certain embodiments, the elongate body portion further comprises a drive arm pivotably connected to the lever element and to the securing element. In certain embodiments, the drive arm is housed within the elongate body portion. In certain embodiments, the elongate body portion comprises a cylindrical extension at a distal end thereof. In certain embodiments, a circular base plate is located at the distal end of the elongate body portion which is mounted onto the cylindrical extension.
In certain embodiments, the securing element further comprises a projection which extends towards the elongate body portion. In certain embodiments, the projection is hollow and comprises a bore sized to accommodate a portion of the drive arm. In certain embodiments, the portion of the drive arm is located within a portion of the elongate body portion.
In certain embodiments, the elongate body portion further comprises at least one cut-out portion.
In certain embodiments, the apparatus further comprises a handle element connectable to the elongate body portion. In certain embodiments, the handle portion comprises a hexagonal-shaped end portion. In an embodiment, the handle portion comprises a protrusion which is configured for location in an aperture in an upper surface of the elongate body portion.
In certain embodiments, the protrusion is spring-loaded.
In certain embodiments, the elongate body portion comprises a further aperture on an upper surface thereof.
In certain embodiments, the elongate body portion is arcuate. In certain embodiments, the elongate body portion is substantially straight.
In certain embodiments, the lever element comprises an arcuate portion and a flattened portion, wherein the flattened portion is configured to locate at least partially within a recessed portion of the grippable portion.
In certain embodiments, the lever element comprises a straight portion and a flattened portion wherein the flattened portion is configured to locate at least partially within a recessed portion of the grippable portion.
In a further aspect of the present invention there is provided a system comprising the device as described herein and an Introducer apparatus as described herein.
Embodiments of the present invention will now be described hereinafter, by way of example only, with reference to the accompanying drawings in which:
As used herein, the term “distal” refers to components which are distal with respect to the surgeon or user of the apparatus. The term “proximal” refers to components which are proximal with respect to the surgeon or user of the apparatus. Unless indicated otherwise, like numerals relates to like parts.
Furthermore, the system may comprise an acetabular component 200, 300, 400, 500. The acetabular component may be a component known in the art such as for example a trial prosthesis or an acetabular prosthesis or the like.
As shown in
The apparatus 100 comprises a proximal portion 102 which comprises a grippable handle portion 104. The apparatus further comprises a distal portion 106 which is advanced towards the surgical site in the patient's acetabulum during use. The distal portion and the proximal portion may comprise a longitudinal axis in a common plane.
The apparatus further comprises a connecting portion 108 intermediate the proximal portion and the distal portion. The connecting portion is elongate and may be hollow in certain embodiments. The connecting portion comprises an arm portion 110 which is connected to the distal portion 106. The arm portion comprises a longitudinal axis (A). The connecting portion 108 further comprises an alignment guide portion 112 extending between the proximal portion and the arm portion. Aptly, the alignment guide portion 112 is integrally formed with the proximal portion 102 and the distal portion 106. The alignment guide portion 112 comprises a first branch portion 114 and a second branch portion 116. The alignment guide portion therefore comprises a triangular shaped section as shown in
The alignment guide portion also includes a central portion 118 from which the first branch portion and the second branch portion extend generally symmetrically e.g. at an angle of around 40° from each other. The first branch portion 114 comprises at least one alignment surface 120 which can be used to align the positioning apparatus 100 with the coronal plane of the patient on the operating table. The patient is in the supine or lateral position on the operating table. Particularly and as described below, the plane of the alignment surface 120 of the first branch portion is aligned parallel to the patient's coronal plane in order to align an acetabular component at between 10 to 20° anteversion in the patient's prepared acetabulum. The alignment surface 120 of the first branch portion is used to align an acetabular component in the right hip. The first branch portion 114 may include a visual indicator e.g. “RIGHT” to show the surgeon to use the alignment surface 120 for aligning an acetabular component in the right hip.
The second branch portion also comprises an alignment surface 122. The alignment surface 122 can be used to align an acetabular component in an acetabulum of the patient with between around 10 to 20° anteversion. The plane of the alignment surface 122 of the second branch portion is aligned parallel to the patient's coronal plane in order to align an acetabular component at around e.g. 20° anteversion in the patient's prepared acetabulum. The alignment surface 122 of the second branch portion is used to align an acetabular component in the left hip. The second branch portion 116 may include a visual indicator e.g. “LEFT” to show the surgeon to use the alignment surface 122 for aligning an acetabular component in the left hip.
The first and second branch portions are integrally formed with both the proximal portion i.e. a handle portion, and the distal portion i.e. the insertion end region. As a result, the apparatus of certain embodiments may be easy to use and manufacture. The apparatus as described herein does not contain sharp ends, which may help to reduce injury during surgery. Furthermore, the apparatus of certain embodiments may be sterilised as a single piece and re-used.
The arm portion is generally orthogonal to the alignment guide portion. The arm portion is generally linear and elongate. The arm portion can be used during surgery to align the acetabular component in a correct inclination in the acetabulum. Particularly, the longitudinal axis (A) of the arm portion is aligned at 90° relative to the axis of the patient, when the patient is in the supine or lateral position on an operating table. The alignment of the arm portion orthogonal (i.e. 90°) to the patient's longitudinal axis typically results in the acetabular component being inclined at 45° in the patient's acetabulum.
As shown in
Also shown in
In some embodiments, the protrusion 126 is configured to fit within an aperture of an insertor plate as described herein. In certain embodiments, the apparatus is integrally formed as a unitary body.
Certain embodiments of the present invention provide a device for introducing an acetabular component into an acetabulum of a patient.
The introducer plate comprises a central aperture 9 which is substantially keyhole shaped. A lower portion 11 of the central aperture has a wider diameter than the upper portion 13.
The upper protrusion 5 is generally circular and comprises at least one slit. The illustrated embodiment comprises two slits 15a, 15b. The slits extend from the outer perimeter of the upper protrusion towards but not extended into the central aperture. The slits form at least two wing portions e.g. 17a and 17b as shown in
The inserter plate may be formed from any suitable material including for example plastic. The use of the inserter plate may confer a number of advantages over existing technologies including for example it enables fixation of a non-cemented acetabular component (“cup”) with a strong retention force and good load transmission on the inside of the cup and on the ring when impacting the cup. Additionally, it may enable fixation of a cemented cup with a strong retention force when introducing and aligning the cup and also be completely loose from the cup when releasing the instrument. In addition, the cup may be fully covered to prevent cement inflow. For embodiments in which the introducer plate and system is used to implant a cemented acetabular component, the retention force of the cup on the Introducer Plate is fully controlled by the surgeon's hand. There is little or no movement of the cup when the apparatus is withdrawn from the surgical site. Furthermore, it may provide a loose connection for a cemented cup but fully covers the cup to prevent cement inflow.
In certain embodiments, the introducer plate may comprise one or more visual cues e.g. a notch (not shown) which can be aligned with a corresponding indicator on an acetabular component. In certain embodiments, the geometry of the introducer plate exactly fits into the inner geometry of the cup including the 6° cylindrical cover. The introducer plate covers the rim of an acetabular component. In certain embodiments, the inserter plate can be used with an introducer apparatus described below. In these embodiments, a lever provided by the introducer apparatus can tighten the fit of the introducer plate within the acetabular component.
The central protrusion of the apparatus is designed to allow coupling with the Introducer Plate. The central protrusion of the apparatus is fixed and static unlike the central protrusion of an introducer apparatus described below. When the Introducer Plate is mounted onto the apparatus, the cup has a loose fixation. The outer annular rim of the introducer plate is configured to contact the rim of the acetabular component and thus allows aligning the acetabular prosthesis according to desired angles of inclination and anteversion to the indicated angles.
The central protrusion is passed through the keyhole shaped aperture at its greatest diameter. The Introducer plate is then slid downwardly so that the central protrusion is accommodated in and through the keyhole shaped aperture at its smaller diameter, thus enabling the central protrusion to fit in the middle of the Introducer Plate.
In some embodiments, the introducer plate may be for use with an apparatus for inserting an acetabular component other than the apparatus of the first aspect. For example, the introducer plate may be for use in a system which comprises an apparatus for inserting an acetabular component such as the introducer apparatus 1000 and 1100 shown in
The Introducer apparatus can be used in at least four different configurations. For example in certain embodiments, the Introducer apparatus 1100 may be curved as shown in
An alternative embodiment of an Introducer apparatus 1000 is shown in
As shown in
The inner lever extends from an entry port 1150, shown in
The projection 1210 and the outer surface of the cylindrical distal portion of the drive arm are threaded to enable the cone to be secured to the drive arm.
By pulling the inner-lever in a direction towards a first handle 1125 of the apparatus to the handle, the user pulls the cone toward the Introducer plate causing its “wings” to spread and allows a tight coupling with the acetabular cup placed on it. The first handle 1125 comprises a grippable surface.
The cone of the embodiment shown in
As mentioned above, the Introducer base body can be coupled with an inner-lever for cementless implantation of the acetabular components. In this case the inner-lever is designed to be a self-locking lever, which means that when tightened, it doesn't need to be held and will stay locked even when the user removes their hand from handle. An example of an apparatus comprising a self-locking lever is shown in
The apparatus comprises a plate 1130 to which the cone is fixed. The Inserter plate rests against the plate 1130 when positioned over the cone. Furthermore, the apparatus comprises a fixation point 1140 where the inner-lever is pivotably attached to the Introducer base-body.
In the context of a non-self-locking inner lever as shown in
The inner-lever or drive arm is provided inside the base body via an opening shown in
The self-locking lever is shown in
The self locking lever further comprises an eyelet on the external portion thereof which can be used to release the lever from the handle when required.
In certain embodiments, the introducer plate can be used with an Introducer apparatus as described herein for cemented implantation of an acetabular component. For example, the introducer plate can be coupled with an apparatus which comprises an inner lever which is not a self-locking lever. In this embodiment, the inner-lever needs to be held by a user at an end portion thereof adjacent to the handle portion. The user grips both the end portion 1165 and the handle simultaneously. The end portion and therefore the inner lever will be released (open) when the user removes their hand from the handle. This embodiment is particularly useful when implanting with cement, as the acetabular component must be held still.
Conversely when using a self-locking inner-lever, the release of the shell is only possible by unlocking the self-locking mechanism, an action which causes little shocks which are not desirable for implantation with cement. Thus, a non-self-locking mechanism allows a very smooth and controlled release of the shell without little shocks.
Aptly, when an introducer apparatus is used in the system, the central protrusion or equivalent cone is mobile and when tightened, the cone presses against the Plate which has the effect to spread the wing portions of the introducer plate toward the outside. The wing portions are considered to be the end portions of the upper protrusion. When spreading toward the outside they are moving in direction of the arrows shown in
When an acetabular component is placed on the introducer plate, the spreading of the wing portions creates a pressure on the inner rim of the shell allowing a tight coupling between the Shells and the Plate and thus between the Shells and the Introducer apparatus. When releasing the force on the wing portions, the connection between Cup and Introducer Plate is completely loose. Depending on the used mechanism of moving the cone, either self-locking or full control of applied force by the user can be achieved.
In certain embodiments, the more force is applied on the actuating handle (e.g. a lever), the more the Introducer Plates wings are spread, the more the cup is engaged. If the force on the lever is removed, the cup is completely loose.
In certain embodiments, the introducer apparatus comprises a second handle 1220 that is detachable from the base body 1105. The handle is attachable to the base body generally towards the distal region thereof. The handle comprises a shaft 1225 having a longitudinal axis. The longitudinal axis of the handle shaft provided at an angle of between about 35° and about 70° to a longitudinal axis of the Introducer apparatus. In some embodiments the angle is between about 45° and about 60°.
The handle may comprise a distal end region which includes an end portion 1230 that includes a hexagonal or “Allen”-type wrench portion. The Allen wrench portion is designed to interact with the recess of the cone 1215 described above.
The handle 1220 may be secured to the base body by any suitable fixing means. In the embodiment shown in
The base body further comprises an aperture 1245 on an upper surface thereof. The aperture is sized to accommodate a protrusion 1250 located on the handle. The protrusion 1250 is spring loaded so it can be depressed as the handle is driven into the groove and then located and secured in the aperture. A user may depress the protrusion and pull the handle away from the base body in order to detach the handle from the base body.
The handle also comprises a thickened portion 1255 which provides a stop to limit movement of the handle along the groove of the base body. As shown in
The handle may comprise a flattened end portion 1265 at a proximal end region 1270. The handle 1220 is used by the surgeon to manoeuvre the introducer apparatus during surgery.
In certain embodiments, the base body further comprises a second aperture 1275 located distally from the aperture. The second aperture is provided to enable the groove and the elongate body portion generally to be washed and flushed out thus improving the cleanability of the base body.
The embodiments of
In certain embodiments, the introducer apparatus is also used as an impactor apparatus.
The embodiment shown in
In certain embodiments, there is provided a system comprising a device as described above. The device may also be referred to as an introducer plate. The system may further comprise a positioning apparatus as described herein. The positioning apparatus may also be referred to herein as an introducer.
In certain embodiments, apparatus, devices and methods described herein are for use in surgery to implant a POLARCUP® acetabular component manufactured by Smith & Nephew.
In preparation for the method of hip surgery according to certain embodiments of the present invention, X-rays of the patient's pelvic region may be taken. In certain embodiments, preoperative X-Rays should include an anterior-posterior projection (AP) of the pelvis centered over the symphysis and an AP and lateral projection of the affected hip. Aptly, templating can be done on the affected side, but it is important that the contralateral hip also be templated to verify the size. To ensure a congruent fit, the acetabular component should be medialized to the medial aspect of the acetabulum, as indicated by the teardrop. The center of rotation also should be marked for subsequent reference.
In certain embodiments, the acetabulum of the patient is completely exposed. Approaches may vary between surgeons but in one embodiment, the method first comprises resecting the acetabular labrum. A blunt retractor may be placed anteriorly. After the transverse acetabular ligament is identified, a blunt retractor can be placed around the inferior margin of the acetabulum. Depending on the exposure, a third retractor can be placed posteriorly following the excision of the labrum. Overhanging soft tissue and osteophytes are removed in order to visualize the entire acetabular socket. The acetabulum should be medialized to restore the normal center of hip rotation.
Aptly the surgery is performed with the patient in an extended supine or lateral position. Access to the operative site is based on previously recorded patient data or the preference of the operating surgeon(s).
The joint capsule may be opened and, if necessary, completely resected. Aptly the acetabulum is then exposed to provide a good view and create sufficient space for the reaming instruments. The osteophytes from the edge of the hip joint cup and the acetabular fossa are then removed followed by cleaning of the hip joint cup.
The acetabulum is then prepared with a reamer, avoiding excessive reaming on the periphery to avoid bone loss. Reaming is continued with increasing diameters (in 2 mm steps), taking into consideration the final anteversion and inclination, until the cartilage is completely removed.
For cemented cups, the last reamer size used should be at least two sizes larger than the implanted size (e.g. size 55 mm reamer=size 51 mm implant) which produces a layer of cement of approximately 2 mm all around.
In certain embodiments, the apparatus as described herein is used to align cemented prostheses. Aptly, the device for introducing the prosthesis is placed at the distal end of the apparatus, with the protrusion of the apparatus being positioned through the hole of the device (also referred to herein as “introducer plate”) until the Introducer Plate touches the metal plate of the apparatus. The Introducer Plate is then pressed against the protrusion of the apparatus until a click is heard.
The wing portions of the Introducer Plate are snapped over the protrusion.
The acetabulum is washed out and dried before applying the cement. An acetabular prosthesis of the appropriate size is then placed on the Introducer plate which is in turn attached to the apparatus. In certain embodiments, the prosthesis comprises a notch or other visual indicator which can be aligned with a corresponding visual indicator e.g. a notch located on the Introducer Plate.
The prosthesis can then be placed into the wound, by holding it on the apparatus by hand. In certain embodiments, the combination of the apparatus and introducer plate (device) as described herein allows a loose connection between the introducer plate and the acetabular component but also fully covers the acetabular component to prevent cement inflow.
Furthermore, the introducer plate as described herein (also referred to as a device) enables fixation of an acetabular component for use with cement with a strong retention force when introducing and aligning the prosthesis but is completely loose from the prosthesis when the apparatus is released and withdrawn from the acetabular component when in situ in the surgical site.
The acetabular component is inserted into the acetabulum by placing the 6° cover in a superior posterior position and pressing the acetabular component into the cement. In certain embodiments, the acetabular component is then aligned into 45° inclination and 20° anteversion by using the connection between the Introducer Plate and the acetabular component rim.
20° anteversion: For right hips the first branch portion may be held in parallel to the coronal plane of the patient. Aptly, in certain embodiments the first branch portion comprises a visual indicator to indicate it is for use to align an acetabular component intended to be placed in the right hip of the patient. Aptly, the further branch portion may be provided with a visual indicator to indicate that it is for use to align an acetabular component in a left hip. Aptly, for left hips the branch portion labelled with “left” is used and held parallel to the coronal plane of the patient. For right hips the arm labelled with “right” is used.
45° inclination: in order to align the acetabular component at 45° inclination, the apparatus is held such that the arm portion is at a 90° position to the patients' axis when the patient is in a supine or lateral position on an operating table. Once the surgeon is content that the acetabular component is in the correct position with respect to inclination and anteversion, the cup is then fixed in place by the surgeon. The apparatus is withdrawn from the wound site.
The surgeon then completes the surgery and closes the wound.
In certain embodiments, the acetabular component is an acetabular shell or cup intended for use with a fixation material such as cement. In other embodiments, the acetabular component is a trial prosthesis e.g. a trial acetabular component. In yet further embodiments, the acetabular component may be an acetabular shell. The shell may comprise pegs and/or flanges for example. The acetabular component may be formed from known materials suitable for implants e.g. titanium, stainless steel, chromium, cobalt or alloys thereof.
In certain embodiments, the introducer plate can be used to introduce non-cemented acetabular components in a prepared acetabulum of a patient. For example, a curved or straight introducer apparatus can be used to place the acetabular component into the surgical site. Suitable introducer apparatus are described herein and shown in
As noted above, in certain embodiments, the introducer plate can be used with an Introducer apparatus as described herein for cemented implantation of an acetabular component. For example, the introducer plate can be coupled with an apparatus which comprises an inner lever which is not a self-locking lever. In this embodiment, the inner-lever needs to be held by a user as they grip the handle. The inner lever will be released (open) when the user removes their hand from the handle. When the inner lever is released, this causes retraction of the wing portions of the introducer plate which is located at the distal end of the apparatus. The retraction of the wing portions enables an acetabular component located on the introducer plate to be released.
This embodiment is particularly useful when implanting with cement, as the acetabular component must be held still. When using a self-locking inner-lever, the release of the shell is only possible by unlocking the self-locking mechanism, an action which causes little shocks which are not acceptable for implantation with cement. Thus, a non-self-locking mechanism allows a very smooth and controlled release of the shell without little shocks.
In embodiments in which acetabular components are implanted without cement, the introducer apparatus may comprise a self-locking inner lever as described above. The self-locking inner lever enables an acetabular component which is mounted on the introducer plate which is in turn mounted on the central protrusion of the apparatus to be retained. The user can take their hand away from the handle and still retain the acetabular component on the introducer plate.
Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to” and they are not intended to (and do not) exclude other moieties, additives, components, integers or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.
Features, integers, characteristics or groups described in conjunction with a particular aspect, embodiment or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of the features and/or steps are mutually exclusive. The invention is not restricted to any details of any foregoing embodiments. The invention extends to any novel one, or novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.
The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1810484.4 | Jun 2018 | GB | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2019/066982 | 6/26/2019 | WO | 00 |
