Patent ID: 12193944

DETAILED DESCRIPTION OF THE INVENTION

All publications, patents, patent applications and other references mentioned herein are hereby incorporated by reference in their entireties for all purposes as if each individual publication, patent or patent application were specifically and individually indicated to be incorporated by reference and the content thereof recited in full.

Where used herein and unless specifically indicated otherwise, the following terms are intended to have the following meanings in addition to any broader (or narrower) meanings the terms might enjoy in the art:

Unless otherwise required by context, the use herein of the singular is to be read to include the plural and vice versa. The term “a” or “an” used in relation to an entity is to be read to refer to one or more of that entity. As such, the terms “a” (or “an”), “one or more,” and “at least one” are used interchangeably herein.

As used herein, the term “comprise,” or variations thereof such as “comprises” or “comprising,” are to be read to indicate the inclusion of any recited integer (e.g. a feature, element, characteristic, property, method/process step or limitation) or group of integers (e.g. features, element, characteristics, properties, method/process steps or limitations) but not the exclusion of any other integer or group of integers. Thus, as used herein the term “comprising” is inclusive or open-ended and does not exclude additional, unrecited integers or method/process steps.

In the context of treatment and effective amounts as defined above, the term subject (which is to be read to include “individual”, “animal”, “patient” or “mammal” where context permits) defines any subject, particularly a mammalian subject, for whom treatment is indicated. Mammalian subjects include, but are not limited to, humans, domestic animals, farm animals, zoo animals, sport animals, pet animals such as dogs, cats, guinea pigs, rabbits, rats, mice, horses, cattle, cows; primates such as apes, monkeys, orangutans, and chimpanzees; canids such as dogs and wolves; felids such as cats, lions, and tigers; equids such as horses, donkeys, and zebras; food animals such as cows, pigs, and sheep; ungulates such as deer and giraffes; and rodents such as mice, rats, hamsters and guinea pigs. In preferred embodiments, the subject is a human.

As used herein, the term “C-shaped profile” means that the plate has a curved profile configured to curve around at least two surfaces of a bone, for example a dorsal and medial side/surface, and provides peripheral laterally-opposed surfaces for screw-receiving holes that are sufficiently laterally spaced apart across the plate to allow fixing screws fix the plate to the bone at or close to an orthogonal configuration (for example the screws may be at 80° to 100° to each other when fixed to the bone, but preferably are disposed at a 90°-90° orientation. The C-shaped profile can extend along the full length of the fusion plate and particularly along the full length of the dorsal and medial sides. The C-shaped profile may be an arc shape configured to extend from 80° to 120° around a bone, 90° to 100°. The plate may include a hemi-spherical arc section. The plate may include lateral sections that are not curved in profile.

As used herein, the term “orthogonal fixing screw configuration” means that the at least two holes at each end of the plate are sufficiently laterally spaced apart such that the fixing screws engage the bone at or close to an orthogonal configuration (at about 80° to about 100°). Ideally the at least two holes are positioned to provide the fixing screws at a 90°-90° orientation.

As used herein, the term “monoblock” as applied to a plate means that the plate is formed in one piece, generally by casting or moulding. It is distinct from plates that are formed in multiple parts and assembled or contoured after formation.

EXEMPLIFICATION

The invention will now be described with reference to specific Examples. These are merely exemplary and for illustrative purposes only: they are not intended to be limiting in any way to the scope of the monopoly claimed or to the invention described. These examples constitute the best mode currently contemplated for practicing the invention.

Referring to the drawings, and initially toFIGS.1to4, there is illustrated a fusion plate of the invention, indicated generally by the reference numeral1, and in this case a fusion plate for MetaTarsoPhalangeal joint (MTPJ) of the big toe. The plate1is shown attached to a first bone (metatarsal)2and a second bone (proximal phalanx)3and spanning the MTPJ4. The plate has a thickness of 1 mm and a length of 4 cm and comprises a proximal end7, distal end8, and a C-shaped cross-sectional profile along its length providing a dorsal side or surface9and medial side or surface10. Holes11for fixing screws12are provided along the dorsal surface9of the plate (FIG.1) and along the medial surface10of the plate (FIG.4). The C-shaped profile of the plate allows the holes on the dorsal and medial sides9,10of the plate1to be sufficiently laterally spaced apart such that when fixing screws12are applied to fix the plate1to the bone, the screws on each side9,10of the plate1engage the bone at approximately 90° to each other. This provides significant stability. In addition, the dorsal and medial holes11are longitudinally staggered, which allows the use of screws12that extend almost fully into and across the bone. This is illustrated in the sectional views ofFIGS.2and3which show a sectional view of the fusion plate in-situ and a fixing screw12A attaching the dorsal surface9of the plate1to the dorsal surface of the metatarsal (FIG.2) and a fixing screw12B attaching the medial surface10of the plate1to the medial surface of the metatarsal. The holes11on the dorsal and medial surface9,10of the plate1do not need to be staggered, but providing staggered holes11allows the use of screws12that are sufficiently long to extend into across most of the bone.

The plate ofFIGS.1to3is shown attached to a MetaTarsoPhalangeal joint (MTPJ) of the big toe of a right foot, and inFIG.4it is shown attached to the same joint of a left foot. In this embodiment, the fusion plate1is cranked intermediate its ends by about 10°, providing for 10° of dorsoflexion. The plate1does not have to be cranked, and may be neutral or provide a different degree of dorsoflexion, depending on the patient. Generally, a surgeon will know in advance of the surgery whether a dorsoflexion fusion plate1is required, and the degree of dorsoflexion that is required.

In the embodiment shown, the fusion plate1has seven dorsal holes11and seven proximal holes11, but it will be appreciated that fewer holes11may be required depending on the joint being treated and the health of the joint. Generally each end of the plate1requires at least two or three holes11, including at least one on each laterally opposed surface of the plate1.

FIG.5shows a perspective view of a fusion plate20according to the invention showing the C-shaped profile of the plate and a central hemi-spherical section21and lateral flat sections22.

FIGS.6to8show the use of the plate to fuse a MetaTarsoPhalangeal joint (MTPJ) of the big toe in patients with different clinical requirements. InFIG.6, the plate has 10° of dorsoflexion. InFIGS.7and10, the plate20is neutral (no dorsoflexion) and is affixed to bone that has been surgically resected due to the patient presenting with a bunion deformity (Hallux valgus). The bunion deformity inFIG.7is less severe, meaning that only a small part25A of the medial eminence of the metatarsal has had to be resected, whereas inFIG.8a larger section of the medial eminence25B has had to be resected. In both cases, resection is performed prior to the plating procedure, and the medial eminence is resected so as to conform to the shape of the proximal end of the C-shaped profile of the fusion plate.

FIGS.9to21show a third embodiment of a meta-tarsal joint fusion plate of the invention generally indicated by the reference numeral30which is broadly similar to the embodiments described inFIGS.1to8and like numerals indicate like parts. Accordingly, the fusion plate30is made up of an elongate plate31with a generally C-shaped cross-sectional profile having a proximal end7and a distal end8together defining a dorsal side9and a medial side10. The C-shaped profile is pronounced at and particularly extends along the full length of the dorsal and medial sides9,10so that the fusion plate30effectively curves around at least two surfaces of a bone2,3. The dorsal and medial sides9,10of the proximal and distal ends7,8are provided with holes11for receiving screws which have been omitted for clarity.

However, in the present embodiment, elongate plate31is shaped and contoured to define a bridging intermediate section40between the proximal end7and the distal end8at the location of the meta-tarsal joint4. The intermediate section40is contiguous with the proximal end7and the distal end8and serves as an articulatable joint or bridge50between the proximal end7and the distal end8so that the fusion plate30can be cranked or flexed about the articulatable joint50as desired by a surgeon in accordance with dorsoflexional requirements.

The elongate plate31is further shaped and configured to define a grafting recess or access window60for facilitating post-fusion plate attachment bone grafting. In the present embodiment, the grafting access window60is located in the medial side10of the fusion plate30between the proximal end7and the distal end8. More particularly, the grafting access window60is a three sided grafting access window60defined by the proximal end7, the distal end8and the intermediate section40so that grafting access window60is positioned at the meta-tarsal joint4in use (see in particularFIGS.13,18and19). In the present embodiment, the articulatable bridge50is shaped to be raised or convex as indicated by the reference numeral70with respect to the elongate plate31so that the grafting access window has a generally inverted U-shape and the articulatable bridge50meets the proximal end7and the distal end8at angles of about 92°. The access window60also facilitates ease of access to and prevents obstruction of the bones2,3during hallux valgus fusion procedures.

The proximal end7of the fusion plate30of the invention is further provided with a compression mechanism80for compressing first and second bones2,3to be fused in a longitudinal direction (see in particularFIGS.15,19and20). In the present embodiment, the compression mechanism80is made up of an elongate compression slot90for receiving a screw on the dorsal side9of the proximal end7of the elongate plate31and an interfragmentary screw hole100for receiving an interfragmentary screw on the distal end8of the elongate plate31. The interfragmentary screw hole100is located in a downwardly inclined guide channel110defined in the dorsal side9of the proximal end so that the interfragmentary screw is correctly guided into bone at an offset angle as shown particularly inFIG.19. In the present embodiment, the guide channel110is formed by an inclined open bore-like extrusion120formed on the dorsal side10.

In the present embodiment, the fusion plate30is described as being provided with the intermediate section40, the grafting access window60and the compression mechanism80. However, as will be appreciated by those skilled in the art, in other embodiments of the invention, the fusion plate30can be provided with these features singly or in any combination as required e.g. a fusion plate30with a compression mechanism80only, an intermediate section40only or a grafting access window60only or any combination of the aforementioned features as required.

In use, the fusion plate30is placed at a meta-tarsal joint4as previously described with the intermediate section40and the grafting access window60positioned at the meta-tarsal joint4as shown in the drawings. If required, the fusion plate30can be flexed as required by the surgeon about the articulatable bride50in accordance with the degree of dorsoflexion required. It should be noted that prior to placement of the fusion plate30, it may be necessary to remove bone material from the second bone3to receive the extrusion120.

Prior to fully tightening screws in the holes11on the proximal and distal ends7,8and a compression screw inserted through the compression slot90, an interfragmentary screw is inserted through the guide channel110to extend between and compress the first and second bones2,3during which the compression screw can slide in the compression slot90in accordance with bone movement. The screws are then tightened to hold the fusion plate30in position.

If bone grafting (whether paste or segmental) is being performed, the dorsal and medial sides9,10hold the bones2,3in position while the bone graft can be placed between the bones2,3as required. Accordingly, in contradistinction with the prior art where bone graft must be placed between bones prior to placing a fusion plate at the joint, the access window60of the fusion plate30of the invention facilitates placement of the bone graft post-fusion plate attachment thus providing for a more anatomic graft and osteotomy.

While numerous orthopaedic plating systems exist for MTPJ fusion the fusion plate of the invention offers a number of unique features which confer an advantage over other plating techniques.1. Greater stiffness in bending: The C-shaped profile of the fusion plate provides optimal fixation and bending resistance where bone contact and bone quality is suboptimal2. Low profile: It is low profile (0.5-1.5 mm) which reduces soft tissue and extensor tendon irritation, and reduces the need for removal.3. Multiplanar fixation: In poor quality bone, where compression/lag screw insertion is not achievable, the locking multi-axial fixation provides stability.4. Severe valgus correction/stability where bone contact is limited: In the setting of hallux valgus correction, and an increased intermetatarsal angle, where the proximal phalanx is translated laterally the fusion plate of the invention can bridge areas of limited contact to offer stable fixation. The fusion plate of the invention offers low profile stabilization in orthogonal planes and provides contoured plates configured to wrap around the dorsal and medial surfaces of the opposing metatarsal and proximal phalanx during the correction of valgus deviation and resection of the prominent medial eminence. In brief the fusion plate of the invention permits translation of the proximal phalanx and stable fixation where bone contact is minimal. It also enables contouring or sculpting of the medial border to address medial prominence.5. The fusion plate can be easily shaped as required through dorsoflexion.6. Bone grafting can be performed through the bone graft access window thus providing for post-fusion plate attachment to provide for a more anatomic graft and osteotomy.

EQUIVALENTS

The foregoing description details presently preferred embodiments of the present invention. Numerous modifications and variations in practice thereof are expected to occur to those skilled in the art upon consideration of these descriptions. Those modifications and variations are intended to be encompassed within the claims appended hereto.