Patent Description:
A growth plate, also known as the epiphyseal plate or physis, is a growing area of tissue adjacent to the diaphysis at each end of a long bone. The growth plate determines the future length and shape of the mature bone. The plate is found in growing children and adolescents. When growth is complete, the growth plate is replaced by an epiphyseal line of solid bone.

In some children, a growth plate will grow non-uniformly, with growth on one side of the growth plate being faster than on another side, causing an angular or a rotational deformity of the bone. Angular and rotational deformities may be congenital, caused by trauma or result from bone diseases. Rotational malalignment can be congenital, that is, present at birth. Neuromuscular disorders including cerebral palsy can also cause rotational and angular malalignment via abnormal muscle forces acting on the bone. Rotational malalignment can also be idiopathic, that is, of no known cause.

With rotational deformities, the most common current method of treatment involves subjecting the patient to an invasive osteotomy, whereby a region of the bone is cut and rotated to achieve re-alignment, typically about a joint, although in effect any section of the bone can be cut and rotated to achieve correction.

Rotational guided growth has been attempted by the use of non-orthogonal tension band plates (<NPL>). This method causes a torsional moment on the growth plate and effects a rotational deformity of the bones as the plates move from a non-orthogonal to an orthogonal position.

<CIT> discloses a bone alignment implant which includes a first bone fastener with a first bone engager that is adapted for fixation into the metaphyseal bone and a second bone fastener with a second bone engager that is adapted for fixation into the diaphyseal bone. A link connecting the two fasteners spans across the physis. Alternatively, the bone alignment implant is adapted for fixation into the diaphyseal sections of two adjoining vertebral bodies. These implants act as a flexible tethers between the metaphyseal and the diaphyseal sections of bone during bone growth. These implants are designed to adjust and deform during the bone realignment process. When placed on the convex side of the deformity, the implant allows the bone on the concave side of the deformity to grow. During the growth process the bone is then realigned.

According to the present invention, there is provided an orthopaedic device for securing between first and second regions of bone separated by a growth plate, the orthopaedic device comprising: a first portion comprising at least two fixing points to secure to a first fixing location on the first bone region and a base configured to extend from the fixing points, the base including a securing point; a second portion comprising a single fixing point to secure to a second fixing location on the second bone region; the first portion and second portion pivotally coupled to each other around the securing point of the first portion; the first portion when secured to the first fixing location and the second portion when secured to the second fixing location being offset relative to a longitudinal axis of the bone; wherein movement of the first and second portions away from each other in a direction parallel to the longitudinal axis of the bone as it grows causes relative rotation of the first and second bone regions, wherein the at least two fixing points of the first position hold the first portion in said first configuration during growth of the bone.

In some embodiments, movement of the first and second portions away from each other may cause the orthopaedic device to move from a first configuration to a second, extended configuration.

In some embodiments, the first portion may comprise a T-plate or an L-plate.

In some embodiments, the first and second portions may be pivotally coupled by a hinge. The hinge may be a multiaxial hinge, including a ball and socket joint.

In some embodiments, the first portion may comprise a post which interacts with a slot in the second portion to form the hinge. The post may be slidable within the slot such that the distance between the second location and a centre of rotation of the hinge increases as the first and second portions are moved away from each other.

The first and second portions may be pivotally coupled by a flexible link.

The flexible link may comprise one or more of: bands, loops, chains, tapes, strings, ropes, wires or the sutures or forms a continuous loop.

The first portion may comprises a first coupling slot for securing the link to the first portion at the first coupling location. The second portion may comprise a second coupling slot for securing the link to the second portion at the second coupling location. The first or the second coupling slot may be curved. The first or second coupling slot may comprise first open end and a second open end respectively for receiving the link.

<FIG> schematically illustrate a state of the art orthopaedic device <NUM> for use in correcting a rotational abnormality in a femur <NUM> of a subject. <FIG> depicts the device <NUM> at the time of fixing to the femur <NUM>. <FIG> depicts the device <NUM> after a duration of growth of the femur <NUM>. Referring to <FIG>, the device <NUM> comprises a plate <NUM> fixed obliquely across a growth plate <NUM> of the femur <NUM> between a lateral location <NUM> on a distal region <NUM> of the femur <NUM> and a medial location <NUM> on a proximal region <NUM> of the femur <NUM>, the distal and proximal regions <NUM>, <NUM> being separated by the growth plate <NUM>. The plate <NUM> may be fixed to the femur <NUM> using screws or nails (not shown) commonly used for fixation of known orthopaedic implants to bone. Whilst in <FIG> the orthopaedic device <NUM> is shown fixed to the front of the femur <NUM>, in other examples the orthopaedic device <NUM> may be fixed to a lateral or medial side of the femur <NUM>.

As the bone grows in a direction parallel to the longitudinal axis of the femur <NUM>, the device <NUM> (or combination of devices) imparts a torque on the distal region <NUM> of the femur <NUM> relative to the proximal region <NUM> which, in turn, causes the distal region <NUM> to rotate relative to the proximal region <NUM>. This rotation continues during growth of the femur <NUM> until, as shown in <FIG>, the lateral location <NUM> and the medial location <NUM> are substantially aligned with one another in a direction parallel to the longitudinal axis of the femur <NUM>.

The total longitudinal growth BC between the initial position of the device <NUM> shown in <FIG> and the final position of the device shown in <FIG> may be defined as follows: <MAT> where AC = AE. For distances AB = <NUM> and AE = <NUM>, the total longitudinal growth allowed for by the device <NUM> can be calculated using the above formula as <NUM>. With the device causing a total relative rotation of the distal and proximal regions <NUM>, <NUM> of <NUM>°, this gives a rotation of <NUM>° per millimetre of growth.

The prior art orthopaedic device <NUM> therefore has the ability to correct a rotational abnormality across a growth plate. However, the inventors have realised that there are some disadvantages associated with use of this device <NUM>. Specifically, it has been found that the amount of rotation imparted by the device <NUM> per millimetre of growth of the bone <NUM> can lead to strain and even cause damage to the growth plate during longitudinal growth of the bone. Additionally, once the device <NUM> reaches its final position as shown in <FIG>, the bone is inhibited from growing any further in the direction parallel to the longitudinal axis of the bone. In many cases, the device <NUM> must then be removed at or prior to the device <NUM> reaching its final position as shown in <FIG> in order to prevent the device <NUM> from causing long term damage or further bone abnormalities.

Having regard to the drawbacks of the above described orthopaedic device <NUM>, <FIG> show perspective, front and side views of a novel orthopaedic device <NUM> according to an embodiment of the present disclosure. The device comprises a first portion <NUM> and a second portion <NUM> coupled by a loop <NUM>.

The first portion <NUM> is in the shape of a T-plate and comprises a pair of fixing points 208a, 208b located at the top of the T for securing the first portion <NUM> to a first region of bone, and a securing point <NUM> at the base of the T for coupling the flexible link <NUM> thereto. Preferably, as shown best in <FIG>, the first portion <NUM> is contoured to match the surface of the first portion of bone to which the first portion <NUM> is to be secured. In the embodiment shown, the base of the T of the first portion <NUM> is bent away from the surface of the bone to avoid the first portion <NUM> from interfering with the growth plate as will become more evident in <FIG>. In other embodiments, however, the first portion <NUM> and/or the second portion <NUM> may contour closer to the bone to reduce irritation to tissue surrounding the device <NUM>. Preferably, however, the first portion <NUM> and/or the second portion <NUM> are contoured to protect the region between the first and second regions of bone.

The second portion <NUM> comprises a fixing point <NUM> for securing the second portion <NUM> to a second region of bone as well as one or more securing points <NUM> for coupling the flexible link <NUM> to the second portion <NUM>.

The first portion <NUM>, the second portion <NUM> or both may be malleable such that during surgery, a clinician is able to mould the device <NUM> to conform with the bone to which it is to be attached to and to ensure the device <NUM> does not interfere with the growth plate or other tissue around the bone. The first portion <NUM> and/or the second portion <NUM> of the device <NUM> (or any other device described herein) may be manufactured from aluminium, lead or similar malleable material to allow the clinician to mould the device <NUM> during surgery.

The flexible link <NUM> may comprise one or more bands, loops, chains, tapes, strings, ropes, wires or the sutures. The flexible link may be manufactured from stainless steel, polyester, polymer fibre (e.g. SuperCable (RTM)), polyethylene such as ultra-high molecular weight polyethylene (UHMWPE), silk, nylon, polyethylene terephthalate, polytetrafluoroethylene (PTFE), polyurethane, polypropylene, polyvinylidene fluoride, polydioxanone, or any combination thereof. Examples UHMWPE products include Dyneema (RTM) and FiberWire (RTM), FiberWire (RTM) comprising a UHMWPE core with a braided jacket of polyester. The flexible link <NUM> may be continuous, forming a loop between the securing point <NUM> of the first portion <NUM> and the securing point <NUM> of the second portion <NUM>.

<FIG> show the device <NUM> fixed to the femur <NUM> of a subject in a similar manner to the device <NUM> shown in <FIG>. Like parts of the femur <NUM> have been denoted with like numbering. Whilst in <FIG> the device <NUM> is shown fixed to the front of the femur <NUM>, in other embodiments the device <NUM> may be fixed to a lateral or medial side of the femur <NUM>. Where two devices <NUM> are provided, as described below in more detail, the two devices <NUM> may be positioned one on the lateral side and the other on the medial side of the femur <NUM>.

<FIG> shows the configuration of the device <NUM> at the time of fixation to the femur. The first portion <NUM> of the device <NUM> is fixed at a lateral location on the distal portion <NUM> of the femur <NUM> and the second portion is fixed at a medial location on the proximal portion <NUM> of the femur <NUM> across the growth plate <NUM>. The lateral and medial fixation sites are offset relative to the longitudinal axis of the femur <NUM>. The first portion <NUM> is preferably fixed to the femur <NUM> such that it extends across the growth plate <NUM> with the securing point <NUM> situated on other side of the growth plate <NUM> to that the first portion <NUM> is fixed. This prevents the flexible link <NUM> from interfering with the growth plate <NUM>. In other embodiments, the device <NUM> may be attached to the bone such that second portion <NUM> extends across the growth plate <NUM>, for similar reasons.

As the bone grows in a direction parallel to the longitudinal axis of the femur <NUM>, tension in the flexible link <NUM> imparts a torque on the distal region <NUM> of the femur <NUM> relative to the proximal region <NUM> which, in turn, causes the distal region <NUM> to rotate relative to the proximal region <NUM> as shown in <FIG>.

The device <NUM> continues to apply torque during further longitudinal growth of the femur <NUM> until, as shown in <FIG>, the first and second portions <NUM>, <NUM> are substantially aligned with one another in a direction parallel to the longitudinal axis of the femur <NUM>.

It can be seen in this embodiment, as is the case in further embodiments described above, the securing point <NUM> is offset relative to the fixing points 208a, 208b in a direction parallel to the longitudinal axis of the bone and towards the growth plate. The flexible link <NUM> then provides a pivot about the securing point <NUM> which enables the distance between the fixation point on the proximal region <NUM> of the femur <NUM> and the fixation point on the distal region <NUM> of the femur <NUM> to increase during longitudinal growth of the femur <NUM>. In other words, the provision of the pivot enables a greater amount of longitudinal growth per degree of rotation when compared to the oblique plate device <NUM> described with reference to <FIG>, as evidenced by the following calculations.

Referring to <FIG>, the total longitudinal growth of the femur <NUM> - CD - between the initial position shown in <FIG> and the final position shown in <FIG> is as follows where BD = BE: <MAT> Given the following dimensions of the device, AB = <NUM>, BC = <NUM>, AE = <NUM>, BE = <NUM>, and CD = <NUM>, then the original positions of the fixing locations on the distal and proximal regions <NUM>, <NUM> on the femur <NUM> for the device <NUM> are the same as those of the device <NUM> when secured to the femur <NUM>. However, contrary to the device <NUM> shown in <FIG>, the total longitudinal growth provided for by the device <NUM>, as calculated by the above equation, is <NUM> when compared to <NUM> of longitudinal growth allowed by the prior art device <NUM>. With the device imparting a relative total rotation of <NUM>°, this gives a rotation of <NUM>° per millimetre of growth.

Thus, the device <NUM> achieves more elongation per degree of rotation as compared to the prior art device <NUM> shown in <FIG>. Thus, the strain placed on the growth plate by the device <NUM> is reduced when compared to the prior art device <NUM> and the bone <NUM> is able to grow by a greater length before removal of the device <NUM> is required.

In <FIG>, a single orthopaedic device <NUM> is shown as being attached across the growth plate <NUM>. This may be desirable where an angular deformity is present in the bone <NUM> as well as a rotational deformity, such as in conditions of bone dysplasia (e.g. Blunts) and in metabolic conditions (e.g. rickets). In such an embodiment, the rotational torque imparted by the device <NUM> may afford a desired degree of rotation and further also inhibit or slow the growth of the growth plate at one side relative to another side of the growth plate such that the growth plate grows at a slower rate relative to the side opposite to which the device <NUM> is secured.

In some embodiments, however, angular correction may not be desired. In which case, two or more of the devices <NUM> may be secured across the growth plate <NUM>, spaced equally apart from each other around the circumference of the femur <NUM>. The devices <NUM> may then collectively impart a substantially uniform torque around the circumference of the femur <NUM> preventing potentially unwanted angular growth of the bone relative to its longitudinal axis. In such embodiments, the one of the two or more devices <NUM> may be positioned on a lateral side of the femur <NUM>, and another of the two or more devices <NUM> may be positioned on a medial side of the femur <NUM>.

In other embodiments, two or more devices <NUM> may be secured across the growth plate <NUM> until the desired rotational correction is achieved, for example when the first and second portions <NUM>, <NUM> of each device <NUM> are laterally aligned. Then, having achieved the desired rotational correction, one or more of the two or more devices <NUM> may be removed or disabled (e.g. by removing the link between the first and second portions <NUM>, <NUM>) and if desired, a device or devices <NUM> may be left in place to correct an angular deformity, as a clinician sees fit.

<FIG> show side, front and perspective views of another orthopaedic device <NUM> according to an embodiment of the present disclosure, which may be used in a similar manner to the device <NUM> described above.

The device comprises a first portion <NUM> and a second portion <NUM> coupled by a joint <NUM>.

As with the device <NUM> described above, the first portion <NUM> of the device <NUM> is in the shape of a T-plate and comprises a pair of fixing points 308a, 308b located at the top of the T for securing the first portion <NUM> to a first portion of bone. As shown best in <FIG>, the first portion <NUM> is preferably contoured to match the surface of the first portion of bone to which the first portion <NUM> is to be secured. This contour comprises a taper towards the base of the T of the first portion <NUM>. As well as providing a surface for mating with the bone surface, this taper also provides the requisite depth in the first portion <NUM> for elements of the joint <NUM> to be incorporated therein.

The second portion <NUM> comprises a fixing point <NUM> for securing the second portion <NUM> to a second portion of bone as well as one or more securing points <NUM> for coupling the joint <NUM> to the second portion <NUM>.

As mentioned above, the first and second portions <NUM>, <NUM> are coupled by the joint <NUM>. The joint comprises a ball and socket arrangement which acts as a multi-axial hinge to enable the first and second portions <NUM>, <NUM> to move in multiple axes about the joint <NUM>.

In use, the device <NUM> acts in a similar manner to the device <NUM> described above. However, instead of the provision of the flexible link <NUM>, the joint <NUM> provides the pivot between the first and second portions <NUM>, <NUM>. The combination of the first and second portions <NUM>, <NUM> and the joint <NUM> allows the device <NUM> to extend further per degree of rotation as compared to the prior art device <NUM> shown in <FIG>. As such, strain placed on the growth plate during correction is reduced when compared to the prior art device <NUM> and the bone is able to grow by a greater length before removal or disablement of the device <NUM> is required.

<FIG> show a another device <NUM> which is a variation of the device <NUM> shown in <FIG>. The device <NUM> comprises a first portion <NUM> and a second portion <NUM> coupled by a joint <NUM>.

As with the device <NUM> described above, the first portion <NUM> of the device <NUM> is in the shape of a T-plate and comprises a pair of fixing points 508a, 508b located at the top of the T-plate for securing the first portion <NUM> to a first portion of bone. As shown best in <FIG>, the first portion <NUM> is preferably contoured to match the surface of the first portion of bone to which the first portion <NUM> is to be secured. To this end, the first portion <NUM> of the device <NUM> is bent away from the surface of the bone to avoid the first portion <NUM> from interfering with the growth plate <NUM> when secured thereacross.

The joint <NUM>, which couples the first and second portions <NUM>, <NUM> together, comprises a ball and socket arrangement acting as a multi-axial hinge to enable the first and second portions <NUM>, <NUM> to move in multiple axes relative to one another.

In use, the device <NUM> acts in a similar manner to the device <NUM> described above. However, instead of the provision of the joint <NUM> being integrated into the main body of the first portion <NUM>, the joint <NUM> is provided distal to the first portion <NUM>. This allows the distal end of the first portion <NUM> can have a reduced thickness relative to the device <NUM> shown in <FIG>. This in turn may allow the distal end of the first portion <NUM> to be moulded or bent by a surgeon during surgery, for example to better confirm the first portion <NUM> to the bone to which the device <NUM> is mounted.

<FIG> show another orthopaedic device <NUM> which is a further variation of the device <NUM> shown in <FIG>. The device <NUM> comprises a first portion <NUM> and a second portion <NUM> coupled by a joint <NUM>.

As with the device <NUM> described above, the first portion <NUM> of the device <NUM> is in the shape of a T-plate and comprises a pair of fixing points 608a, 608b located at the top of the T-plate for securing the first portion <NUM> to a first portion of bone.

The joint <NUM>, which couples the first and second portions <NUM>, <NUM> together, comprises a post <NUM> integrated into the first portion <NUM> which interacts with a slot <NUM> formed in the second portion <NUM>. The post <NUM> is slidable within the slot <NUM> such that the distance between the fixing point <NUM> and the centre of rotation of the joint <NUM> can increase as the first and second portions <NUM>, <NUM> move away from each other. Thus, the joint <NUM> allows for even more longitudinal extension per degree of rotation than the devices <NUM>, <NUM> and <NUM> shown in the previous figures.

<FIG> show another orthopaedic device <NUM> which is a variation of the device <NUM> shown in <FIG>. The device <NUM> comprises a first portion <NUM> and a second portion <NUM> coupled by a flexible link <NUM>.

The first portion <NUM> is in the shape of an (inverted) L-plate and comprises a pair of fixing points 708a, 708b located at the base of the inverted L for securing the first portion <NUM> to a first region of bone, and a securing point <NUM> at the base of the inverted L for coupling the flexible link <NUM> thereto. As with the device <NUM> shown in <FIG>, first portion <NUM> may be contoured to match the surface of the first portion of bone to which the first portion <NUM> is to be secured. In some embodiments, vertical of the L of the first portion <NUM> may bent away from the surface of the bone to avoid the first portion <NUM> from interfering with the growth plate. In other embodiments, , the first portion <NUM> and/or the second portion <NUM> may contour closer to the bone to reduce irritation to tissue surrounding the device <NUM>. Preferably, the first portion <NUM> and/or the second portion <NUM> are contoured to protect the region between the first and second regions of bone.

As with the device <NUM> of <FIG>, the first portion <NUM>, the second portion <NUM> or both may be malleable such that during surgery, a clinician is able to mould the device <NUM> to conform with the bone to which it is to be attached to and to ensure the device <NUM> does not interfere with the growth plate or other tissue around the bone.

The flexible link <NUM> may comprise one or more bands, loops, chains, tapes, strings, ropes, wires or the sutures and may be manufactured from the same materials as described above in respect of the flexible link <NUM> of the device <NUM> shown in <FIG>. The flexible link <NUM> may also be continuous, forming a loop between the securing point <NUM> of the first portion <NUM> and the securing point <NUM> of the second portion <NUM>.

The L-shaped device <NUM> is anatomically advantageous in that it is able to fit into spaces where other devices might not be able to fit. Additionally, the L-shaped device <NUM> provides less of a footprint, and requires a smaller incision during surgery for insertion under skin and muscle adjacent the bone. Further, the L-shaped device can provide the same rotational offset as the T-shaped device <NUM> but with a smaller footprint.

<FIG> shows another orthopaedic device <NUM> which is a variation of the device <NUM> shown in <FIG>. The device <NUM> comprises a first portion <NUM> and a second portion <NUM> coupled by a flexible link <NUM>.

The first portion <NUM> is in the shape of an isosceles trapezoid or arrow head and comprises a pair of fixing points 808a, 808b located at the base (large parallel side) of the trapezoid for securing the first portion <NUM> to a first region of bone, and a securing point <NUM> located at the short parallel size of the trapezoid (or point of the arrow head) of the first portion for coupling the flexible link <NUM> thereto. As with the device <NUM> shown in <FIG>, first portion <NUM> may be contoured to match the surface of the first portion of bone to which the first portion <NUM> is to be secured. In some embodiments, the narrow portion of the first portion <NUM> where the securing point <NUM> is provided may bent away from the surface of the bone to avoid the first portion <NUM> from interfering with the growth plate. In other embodiments, the first portion <NUM> and/or the second portion <NUM> may contour closer to the bone to reduce irritation to tissue surrounding the device <NUM>. Preferably, the first portion <NUM> and/or the second portion <NUM> are contoured to protect the region between the first and second regions of bone.

The second portion <NUM> comprises a fixing point <NUM> for securing the second portion <NUM> to a second region of bone as well as a securing point <NUM> for coupling the flexible link <NUM> to the second portion <NUM>. The securing point <NUM> of the first portion <NUM> and/or the securing point <NUM> of the second portion <NUM> may each comprise an elongate aperture enabling the flexible link <NUM> to slide along the length of the aperture during relative movement of the first and second portions <NUM>, <NUM>.

The arrow shaped device <NUM> is advantageous in that it provides an indication to a surgeon as to which way the first portion <NUM> is to be mounted relative to the first bone region, i.e. with the arrow pointing towards a growth plate of the bone region.

Like the first portion of the device <NUM> of <FIG>, the first portion <NUM> is in the shape of an isosceles trapezoid or arrow head and comprises a pair of fixing points 908a, 908b located at the base (large parallel side) of the trapezoid for securing the first portion <NUM> to a first region of bone. The first portion <NUM> further comprises a securing slot <NUM> extending from a long edge of the first portion <NUM> towards the point of the arrow head for coupling the flexible link <NUM> thereto. As with the device <NUM> shown in <FIG>, first portion <NUM> may be contoured to match the surface of the first portion of bone to which the first portion <NUM> is to be secured. In some embodiments, the narrow portion of the first portion <NUM> where the securing point <NUM> is provided may bent away from the surface of the bone to avoid the first portion <NUM> from interfering with the growth plate. In other embodiments, the first portion <NUM> and/or the second portion <NUM> may contour closer to the bone to reduce irritation to tissue surrounding the device <NUM>. Preferably, the first portion <NUM> and/or the second portion <NUM> are contoured to protect the region between the first and second regions of bone.

The second portion <NUM> comprises a fixing point <NUM> for securing the second portion <NUM> to a second region of bone as well as a securing slot <NUM> for coupling the flexible link <NUM> to the second portion <NUM>. The securing slot <NUM> of the first portion <NUM> and/or the securing slot of the second portion <NUM> may enable a continuous loop embodiment of the flexible link <NUM> (shown in <FIG>) to be looped therein during surgery, thereby enabling the first and second portions <NUM>, <NUM> to be fitted independently of each other. The securing slot <NUM> in the second portion <NUM> is provided with a kink <NUM> to reduce the likelihood of the flexible link <NUM> falling out of the securing slot <NUM> during relative movement of the first and second portions <NUM>, <NUM> in situ or during movement of tissue over the device <NUM>.

The flexible link <NUM> may comprise one or more bands, loops, chains, tapes, strings, ropes, wires or the sutures and may be manufactured from the same materials as described above in respect of the flexible link <NUM> of the device <NUM> shown in <FIG>. The flexible link <NUM> may also be continuous, forming a loop configured to loop over the securing slot <NUM> of the first portion <NUM> and the securing slot <NUM> of the second portion <NUM>.

Like the first portion of the device <NUM> of <FIG>, the first portion <NUM> is in the shape of an (inverted) L-plate and comprises a pair of fixing points 1008a, 1008b located at a proximate end (base of the inverted L) for securing the first portion <NUM> to a first region of bone. In contrast to the device <NUM>, the device <NUM> comprises a securing mechanism <NUM> at the base of the inverted L for coupling the flexible link <NUM> thereto. The securing mechanism <NUM> comprises an aperture configured to receive the flexible link <NUM> from a distal end of the device <NUM> and a locking pin 1010b configured to lock a portion of the flexible link <NUM> within the aperture. In use, the locking pin 1010b may be pushed into a proximate end of the aperture 1010a as denoted by the black vertical arrow in <FIG> so as to create an interference fit holding the flexible link <NUM> within the aperture 1010a between a surface of the locking pin 1010b and an internal wall of the aperture 1010a.

As with the device <NUM> shown in <FIG>, first portion <NUM> may be contoured to match the surface of the first portion of bone to which the first portion <NUM> is to be secured. In some embodiments, vertical of the T of the first portion <NUM> may bent away from the surface of the bone to avoid the first portion <NUM> from interfering with the growth plate. In other embodiments, the first portion <NUM> and/or the second portion <NUM> may contour closer to the bone to reduce irritation to tissue surrounding the device <NUM>. Preferably, the first portion <NUM> and/or the second portion <NUM> are contoured to protect the region between the first and second regions of bone.

The second portion <NUM> comprises a fixing point <NUM> for securing the second portion <NUM> to a second region of bone as well as a securing mechanism <NUM> for coupling the flexible link <NUM> to the second portion <NUM> in a similar manner to the securing mechanism <NUM> of the first portion <NUM> using a pin or the like (not shown) similar to the locking pin 1010b.

As with the device <NUM> of <FIG>, the first portion <NUM>, the second portion <NUM> of the device <NUM> or both may be malleable such that during surgery, a clinician is able to mould the device <NUM> to conform with the bone to which it is to be attached to and to ensure the device <NUM> does not interfere with the growth plate or other tissue around the bone.

The device <NUM> may be used with a flexible link comprising one or more bands, loops, chains, tapes, strings, ropes, wires or the sutures and may be manufactured from the same materials as described above in respect of the flexible link <NUM> of the device <NUM> shown in <FIG>. The flexible link may also be continuous, forming a loop.

A variation of the device <NUM> shown in <FIG> is shown in <FIG>. An L-shaped device <NUM> is provided comprising a first portion <NUM> and a second portion <NUM> coupled by a flexible link <NUM>, and a pair of fixing points 1108a, 1108b for securing the first portion <NUM> to a first region of bone. In contrast to the device <NUM> of <FIG>, in place of the securing mechanism <NUM>, the device <NUM> a curved securing slot <NUM> is provided in the first portion <NUM> for coupling the flexible link <NUM> thereto. The curved securing slot <NUM> forms an arc which extending through an angular range of rotation enabling the flexible link <NUM> to slide and thus hinge about a point centred at the distal end of the first portion <NUM> of the device <NUM>. The curved securing slop <NUM> may extend through an expected range of rotation of the flexible link <NUM> relative to the first portion <NUM>. The second portion <NUM> may also be provided with a curved securing slot <NUM> similar to the slot <NUM> of the first portion. The second portion <NUM> also comprises a fixing point <NUM> for securing the second portion <NUM> to a second region of bone.

As with the device <NUM> shown in <FIG>, the first portion <NUM> may be contoured to match the surface of the first portion of bone to which the first portion <NUM> is to be secured. In some embodiments, the vertical of the L of the first portion <NUM> may bent away from the surface of the bone to avoid the first portion <NUM> from interfering with the growth plate. In other embodiments, the first portion <NUM> and/or the second portion <NUM> may contour closer to the bone to reduce irritation to tissue surrounding the device <NUM>. Preferably, the first portion <NUM> and/or the second portion <NUM> are contoured to protect the region between the first and second regions of bone.

The first portion <NUM>, the second portion <NUM> or both may be malleable such that during surgery, a clinician is able to mould the device <NUM> to conform with the bone to which it is to be attached to and to ensure the device <NUM> does not interfere with the growth plate or other tissue around the bone.

It will be appreciated that where possible, any of the first portions of the orthopaedic devices described above may be used with any of the second portions of the orthopaedic devices described above. Further any features of any of the device described may be re-arranged in any conceivable arrangement while not departing from the scope of the disclosure.

Use of the orthopaedic devices <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> has been described in relation to correcting rotational deformities across a growth plate of a bone. However, the present disclosure is not limited to such corrections. For example, instead of securing the device <NUM> (or any of the other devices described) across a growth plate, the device <NUM> may equally be used to correct a rotational deformity across a intervertebral disc. <FIG> show the orthopaedic device <NUM> described above with reference to <FIG> attached between a first vertebra <NUM> and a second vertebra <NUM> separated by an intervertebral disc <NUM>. <FIG> shows the device <NUM> at the time of securing to the vertebrae <NUM>, <NUM>. The first portion <NUM> of the device <NUM> is secured at a posterior location on the first vertebra <NUM> and the second portion <NUM> is secured at an anterior location on the second vertebra <NUM>. The anterior and posterior fixation sites are laterally offset relative to the longitudinal axis of the spine.

As the spine grows in a direction parallel to the longitudinal axis of the spine, tension in the flexible link <NUM> imparts a torque on the first vertebra <NUM> relative to the second vertebra <NUM> which in turn causes the first vertebra <NUM> to rotate relative to the second vertebra <NUM> until, as shown in <FIG>, the first and second portions <NUM>, <NUM> are substantially aligned with one another in a direction parallel to the longitudinal axis of the spine.

Each of the other orthopaedic devices <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> described above may be used in a similar manner to the device <NUM> described in <FIG> for rotational correction of the spine as described with reference to <FIG>.

As noted in above with reference to <FIG>, the devices described herein achieve more elongation per degree of rotation as compared to the prior art device <NUM> shown in <FIG>. In addition, the inventors have found that the relative position of implantation of the first and second portions of the devices <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> affects the efficacy of treatment. Specifically, the inventors have identified several variable that can be adjusted to improve the orthopaedic correction provided. These will be described with reference to <FIG> which shows the orthopaedic device <NUM> described above. Using the same notation as that used above with reference to <FIG>, <FIG> shows the initial placement of the first and second portions <NUM>, <NUM> of the device <NUM>.

The angle made between the horizontal and the plane intersecting the rotational centres of the first and second portions <NUM>, <NUM> about which the flexible link <NUM> pivots (points B and E) will be referred to here as the initial device angle (IDA). The inventors have found that the initial device angle can be adjusted to increase the linearity in the rate of corrective rotation of the first and second bone portions. The inventors have also found that the initial distance between the first and second portions <NUM>, <NUM> affects the linearity in the rate of relative rotation of the first and second bone portions. This linearity is dependent on, for example, the distance L between the rotational centres of the first and second portions <NUM>, <NUM> about which the flexible link <NUM> pivots (points B and E). Referring to <FIG>, the inventors have further found that the size of the bone being corrected should also be taken into account when determining the distance between points B and E for initial implantation. Taking the tibia as an example, <FIG> is a transverse view of a distal tibia <NUM>. The distance medial lateral span ML can be used as an indicator of the size of the tibia.

<FIG> is a graph illustrating modelled relative rotation of first and second bone portions (y-axis) over time (x-axis) for different initial device angles of <NUM>°, <NUM>°, <NUM>°, <NUM>°, <NUM>°, and <NUM>°, for the device <NUM> implanted over a tibial growth plate at a distance BE (L) of <NUM> and in a patient with ML of <NUM>. It can be seen that with an IDA of <NUM>°, the rate of rotation of the first and second bone portions changes considerably over time. Further, for the first <NUM> months of implantation of the device <NUM>, the device <NUM> provides less than <NUM>° of corrective rotation. In contrast, implanting the device <NUM> with an IDA of <NUM>° provides a very linear rate of corrective rotation. However, the device <NUM> is limited to providing a total rotation of around <NUM>°. Additionally, the rate of rotation with an IDA of <NUM>° is relatively high which may place too much strain on the growth plate. An IDA of <NUM>° can be seen to provide a relatively linear rate of rotation over a period of about <NUM> months with a total rotational correction of around <NUM>°. As such, preferably the device <NUM> may be implanted with an IDA above <NUM>°, or above <NUM>°, or above <NUM>°, more preferably about <NUM>°. Additionally, the device <NUM> may be implanted with an IDA of below <NUM>°, or below <NUM>°, preferably below <NUM>°. In some embodiments, the IDA may be chosen to be between <NUM>° and <NUM>° or between <NUM>° and <NUM>°, preferably about <NUM>°.

As illustrated in <FIG>, it has also been found that the greater the offset L between the first and second portions <NUM>, <NUM> of the device <NUM>, the more linear the rate of rotation. <FIG> shows relative rotation over time for an IDA of <NUM>° implanted in a patient having an ML of <NUM>. It has been found that a distance L of <NUM> provides a linear rate of rotation over a <NUM> month growth period. Accordingly, in some embodiments, the distance L at which the device <NUM> is implanted may be between <NUM> and <NUM> for example around <NUM>.

It has also been found that the rate of corrective rotation increases with smaller ML distance. This is illustrated in <FIG> which shows the rate of rotation for the device <NUM> implanted with an IDA of <NUM>° and distance L of <NUM> in patients having ML distance of <NUM>, <NUM>, <NUM> and <NUM>.

Having regard for the above, there is a need during surgery to accurately set the IDA and distance L during implantation of the devices described herein. The inventors have devised a surgical guide which enables such accurate positioning and fixing of first and second portions of one or more of the devices <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM> to a patient, e.g. across a growth plate.

<FIG> provide an exemplary surgical guide <NUM> (not claimed) which may be used in conjunction with the device <NUM> described above with reference to <FIG> and <FIG>. The surgical guide <NUM> comprises a mating portion <NUM> configured to mate with the securing slot <NUM> of the device <NUM>, for example by means of a curved tongue (not shown). The surgical guide <NUM> further comprises a guide hole <NUM> separated from the mating portion <NUM> by the distance L chosen for the particular embodiment of the device <NUM>. The mating portion <NUM> may mate with the securing slot <NUM> in only one angular orientation so that the axis intersecting the guide hole <NUM> and the centre of rotation of the slot <NUM> forms and the correct IDA relative to the horizontal. This is denoted best in <FIG> which shows the IDA and distance L with the mating portion matted with the securing slot <NUM>.

During surgery, the first portion <NUM> may be fitted to the first portion of bone. The surgical guide <NUM> may be fitted to the first portion <NUM> and a fixing location identified on the second portion of the bone for fixing of the second portion <NUM> of the device <NUM>. The second portion <NUM> of the device may then be fixe to the second portion <NUM> at the positioned indicated by the surgical guide <NUM> (e.g. the guide hole <NUM>).

It will be appreciated that the length and mating angle of the surgical guide <NUM> may be chosen to enable the first and second portions <NUM>, <NUM> of the device to be fitted at any relative distance and/or angle depending on the requirements of the specific case.

Claim 1:
An orthopaedic device (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) for securing between first and second regions of bone separated by a growth plate, the orthopaedic device comprising:
a first portion (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) comprising at least two fixing points (208a, 208b, 308a, 308b, 508a, 508b, 608a, 608b, 708a, 708b, 808a, 808b, 908a, 908b, 1008a, 1008b, 1108a, 1108b) to secure to a first fixing location on the first bone region in a first configuration and a base configured to extend from the fixing points, the base including a securing point (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>);
a second portion (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) comprising a single fixing point (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>) to secure to a second fixing location on the second bone region;
the first and second portions pivotally coupled to each other around the securing point of the first portion;
the first portion when secured to the first fixing location and the second portion when secured to the second fixing location being offset relative to each other and to a longitudinal axis of the bone;
wherein movement of the first and second portions away from each other in a direction parallel to the longitudinal axis of the bone as it grows causes relative rotation of the first and second bone regions, wherein the at least two fixing points of the first portion hold the first portion in said first configuration during growth of the bone.