DESC:FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(Section 10 and Rule 13)

1. TITLE OF THE INVENTION:
TIBIAL PROSTHESIS

2. APPLICANT:
Meril Corporation (I) Private Limited, an Indian company of the address Survey No. 135/139, Muktanand Marg, Bilakhia House, Pardi, Vapi, Valsad-396191 Gujarat, India.

The following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF INVENTION
[1] The present disclosure relates to a medical prosthesis. More particularly, the present disclosure relates to a tibial prosthesis.
BACKGROUND OF INVENTION
[2] Knee replacement surgery, also known as knee arthroplasty, is a medical procedure aimed at relieving pain and restoring function in severely damaged knee joints. This procedure is typically considered when conservative treatments like medication and physiotherapy no longer provide adequate relief from pain and immobility caused by conditions, such as, osteoarthritis, rheumatoid arthritis, or traumatic injury.
[3] Knee arthroplasty encompasses two types of surgery i.e., total knee replacement and unicompartmental knee replacement. Total knee replacement involves replacing the entire knee joint with prosthetic components such as, for example, a femoral component, a tibial component, a patellar component and a liner. On the other hand, unicompartmental knee replacement, also known as partial knee replacement, targets replacing only affected portion of knee joint. For example, if one side of the tibial joint is affected, the affected part is replaced with prosthetic components such as, for example, a tibial prosthesis having a tibial component and a tibial liner.
[4] In unicompartmental knee arthroplasty, upon implementation, the tibial component acts as a natural tibial joint and the tibial liner act as a cushion between the tibial component and other natural joints and/or prosthesis joints. The tibial liner is coupled with the tibial component. It is critical that the tibial liner remains in place and provides a smooth articulating surface for other natural joints and/or prosthesis joint.
[5] Various tibial liners and tibial components are currently available; however, conventional tibial liners heavily suffer from problems, such as, dislocation, wear and premature failure, etc. due to improper or loose coupling and/or locking with the tibial components. This may lead to a revision surgery, which not only increases the patient’s trauma but also their medical costs.
[6] Thus, there arises a need for a tibial prosthesis that overcomes the problems associated with the conventional prosthesis.
SUMMARY OF INVENTION
[7] The present invention relates to a tibial prosthesis. In an embodiment, the tibial prosthesis includes a tibial component and a tibial liner. The tibial component includes a wall, provided along a periphery of a base of the tibial component and defining a cavity, and a plurality of slots provided on an inner surface of the wall. The tibial liner includes a top portion and a bottom portion. The bottom portion is configured to fit within the cavity of the tibial component. The bottom portion includes a plurality of tabs. Each of the plurality of tabs of the tibial liner is configured to fit within a corresponding slot of the plurality of slots of the tibial component, thereby locking the tibial liner with the tibial component.
[8] The foregoing features and other features as well as the advantages of the invention will become more apparent from the following detailed description, which proceed with reference to the accompanying figures.
BRIEF DESCRIPTION OF DRAWINGS
[9] The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the apportioned drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the disclosure is not limited to specific methods and instrumentality disclosed herein. Moreover, those in the art will understand that the drawings are not to scale.
[10] Fig. 1A depicts an exploded view of a tibial prosthesis 100, in accordance with an embodiment of the present disclosure.
[11] Fig. 1B depicts a cross sectional view of the tibial prosthesis 100, in accordance with an embodiment of the present disclosure.
[12] Figs. 2A-2B depict perspective views of a tibial component 110 of the tibial prosthesis 100, in accordance with an embodiment of the present disclosure.
[13] Figs. 3A-3C depict perspective views of a tibial liner 130 of the tibial prosthesis 100, in accordance with an embodiment of the present disclosure.
[14] Fig. 3D depicts a bottom-view of the tibial liner 130 of the tibial prosthesis 100, in accordance with an embodiment of the present disclosure.
DETAILED DESCRIPTION OF THE DRAWINGS
[15] Prior to describing the invention in detail, definitions of certain words or phrases used throughout this patent document will be defined: the terms “include” and “comprise”, as well as derivatives thereof, mean inclusion without limitation; the term “or” is inclusive, meaning and/or; the phrases “coupled with” and “associated therewith”, as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have a property of, or the like. Definitions of certain words and phrases are provided throughout this patent document, and those of ordinary skill in the art will understand that such definitions apply in many, if not most, instances to prior as well as future uses of such defined words and phrases.
[16] Reference throughout this specification to “one embodiment,” “an embodiment,” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in one embodiment,” “in an embodiment,” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment, but mean “one or more but not all embodiments” unless expressly specified otherwise. The terms “including,” “comprising,” “having,” and variations thereof mean “including but not limited to” unless expressly specified otherwise. An enumerated listing of items does not imply that any or all of the items are mutually exclusive and/or mutually inclusive, unless expressly specified otherwise. The terms “a,” “an,” and “the” also refer to “one or more” unless expressly specified otherwise.
[17] Although the operations of exemplary embodiments of the disclosed method may be described in a particular, sequential order for convenient presentation, it should be understood that the disclosed embodiments can encompass an order of operations other than the particular, sequential order disclosed. For example, operations described sequentially may in some cases be rearranged or performed concurrently. Further, descriptions and disclosures provided in association with one particular embodiment are not limited to that embodiment, and may be applied to any embodiment disclosed herein. Moreover, for the sake of simplicity, the attached figures may not show the various ways in which the disclosed system, method, and apparatus can be used in combination with other systems, methods, and apparatuses.
[18] Furthermore, the described features, advantages, and characteristics of the embodiments may be combined in any suitable manner. One skilled in the relevant art will recognize that the embodiments may be practiced without one or more of the specific features or advantages of a particular embodiment. In other instances, additional features and advantages may be recognized in certain embodiments that may not be present in all embodiments. These features and advantages of the embodiments will become more fully apparent from the following description and apportioned claims, or may be learned by the practice of embodiments as set forth hereinafter.
[19] The present disclosure discloses a tibial prosthesis. The tibial prosthesis of present disclosure includes a tibial component and a tibial liner. The tibial component is securely coupled with the tibial liner using a locking mechanism. In an embodiment, the locking mechanism includes one or more slots provided on the tibial component and one or more tabs provided on the tibial liner. Each slot of the one or more slots is configured to receive a corresponding tab of the one or more tabs, thereby forming a secure locking between the tibial component and the tibial liner. The proposed locking mechanism prevents loosening of the coupling between the tibial component and the tibial liner. Consequently, the proposed tibial prosthesis avoids dislocation of the tibial liner from the tibial component. This minimizes the failure chances of the tibial prosthesis and improves patient outcome.
[20] Referring to figures, Fig. 1A depicts an exploded view of a tibial prosthesis 100 and Fig. 1B depicts a cross sectional view of the tibial prosthesis 100, according to an embodiment of the present disclosure. The tibial prosthesis 100 is used to replace a damaged or diseased tibial joint during a partial knee replacement surgery. In an embodiment, the tibial prosthesis 100 is used to replace/repair injuries in one half of the tibial joint. The tibial prosthesis 100 mimics the structure and function of the natural tibial joint, allowing or improved mobility and reduced pain. Though the present disclosure has been explained in the context of the partial knee replacement surgery, the teachings of the present disclosure can be applied to a tibial prosthesis in a total knee replacement surgery and the same is within the scope of the present disclosure.
[21] The tibial prosthesis 100 includes a tibial component 110 and a tibial liner 130. In an embodiment, the tibial component 110 is coupled to the tibial liner 130 with the help of snap fit locking between the tibial component 110 and the tibial liner 130. The tibial prosthesis 100 includes an anterior end 100a, a posterior end 100b, a medial end 100c and a lateral end 100d. The anterior end 100a, the posterior end 100b, the medial end 100c and the lateral end 100d of the tibial prosthesis 100 are designed to align towards the anterior, posterior, medial, and lateral sides of the tibia, respectively.
[22] It should be understood that the tibial component 110 and the tibial liner 130 illustrated herein are merely exemplary and teachings of the present disclosure can be extended to any suitable tibial components and tibial liners and the same is within the scope of the present disclosure.
[23] Figs. 2A and 2B depict the tibial component 110, according to an embodiment of the present disclosure. The tibial component 110 replaces the damaged or diseased portion of the tibia (shinbone) in patients suffering from severe knee arthritis or injury. In an embodiment, the tibial component 110 is used to replace one half of the natural tibial joint.
[24] In an embodiment, the tibial component 110 has a D-shape, though it may have any other suitable shape. The tibial component 110 includes a base 111a and a wall 120 provided along a periphery of the base 111a. The wall 120 defines a cavity 111. The cavity 111 is configured to receive a portion of the tibial liner 130 (explained later). The wall 120 may include a predefined shape and predefined dimensions, determining the shape of the cavity 111. The shape of the cavity 111 may vary depending upon the portion of the tibial liner 130 that is to be received by the cavity 111. In an embodiment, the cavity 111 is D shaped, though it may have any other suitable shape (e.g., elliptical, square, circular, rectangular, hexagonal, etc.).
[25] The wall 120 of the tibial component 110 includes an inner surface 115. The inner surface 115 of the wall 120 may have a uniform or a non-uniform structure. In an embodiment, the inner surface 115 of the wall 120 includes a plurality of slots. Each slot of the plurality of slots is configured to mate with a corresponding portion of the tibial liner 130 to form a firm locking between the tibial component 110 and the tibial liner 130 as explained later.
[26] In an embodiment, the tibial component 110 includes a first slot 115a and a second slot 115b provided on the inner surface 115 of the wall 120. In an embodiment, the first slot 115a and the second slot 115b are provided on the inner surface 115 of the wall 120 towards the anterior end 100a and the posterior end 100b of the tibial prosthesis 100, respectively.
[27] The first slot 115a and the second slot 115b may have a pre-defined shape, such as, without limitation, rectangular, trapezoidal, circular or semi-circular with flat or angled surface, cylindrical, T-shaped, planar with tight clearance, etc. In an embodiment, the first slot 115a has a rectangular shape. The first slot 115a is configured to receive a corresponding portion of the tibial liner 130 and form an interference locking between the tibial component 110 and the tibial liner 130 at the anterior end 100a of the tibial prosthesis 100, as explained later. In an embodiment, the second slot 115b has a dovetail structure. The dovetail structure of the second slot 115b is configured to mate with a corresponding dovetail structure of the tibial liner 130 to form a dovetail joint between the tibial component 110 and the tibial liner 130 at the posterior end 100b of the tibial prosthesis 100, as explained later. In an embodiment, the first slot 115a and the second slot 115b are provided on opposite sides of the cavity 111 for a more stable fit.
[28] In an embodiment, the tibial component 110 includes one or more chamfered face 117 (hereinafter, chamfered face 117). The chamfered face 117 may be provided on an interior edge of the wall 120 (i.e., an edge of the wall 120 towards the inner surface 115) of the tibial component 110. The chamfered face 117 may be provided at one of: the anterior end 100a or posterior end 100b of the tibial prosthesis 100. In an exemplary embodiment, the tibial component 110 includes one chamfered face 117 provided on the top surface of the wall 120 at the anterior end 100a of the tibial prosthesis 100. The chamfered face 117 provided on the tibial component 110 enables easy coupling of the tibial liner 130 with the tibial component 110, described later.
[29] Additionally, or optionally, the tibial component 110 may include one or more cut-outs configured to receive a corresponding portion of the tibial liner 130. In the depicted embodiment, the wall 120 of the tibial component 110 is provided with two cut-outs, namely, a first cut-out 113a and a second cut-out 113b. The cut-outs (113a, 113b) may be provided towards one of: the anterior end 100a or the posterior end 100b. In an exemplary embodiment, the first cut-out 113a and the second cut-out 113b are provided on the wall 120 of the tibial component 110 towards the anterior end 100a of the tibial prosthesis 100. The first cut-out 113a and the second cut-out 113b may be provided on opposite sides of the wall 120 and may be aligned with each other. For example, the first cut-out 113a is provided on a straight section of the wall 120 and the second cut-out 113b is provided on a D-shaped section of the wall 120. In an embodiment, the cut-outs (113a, 113b) have a rectangular shape, though they may have any other suitable shape. The cut-outs (113a, 113b) enable the surgeon to extract (or unlock) the tibial liner 130 using a medical instrument during revision surgeries as needed. The cut-outs (113a, 113b) may have the same or different shapes and dimensions.
[30] In an embodiment, the tibial component 110 is provided with a keel 119. The keel 119 integrally extends from a bottom surface (not shown) of the tibial component 110. Alternatively or in addition, the tibial component 110 may include one or more pegs (not shown), for example, two pegs, integrally coupled to (e.g., extruded from) the bottom surface of the tibial component 110. The keel 119 and the one or more pegs ensures a secured coupling of the tibial component 110 with the tibia, preventing dislocation/de-attachments of the tibial component 110 from the tibia. The keel 119 may have any suitable shape based upon the requirements. In an embodiment, the keel 119 is C shaped. The one or more pegs may have any suitable shape, such as, without limitation, cylindrical, cuboidal, tapered, frustum, hour-glass, etc.
[31] The dimensions of the tibial component 110 may vary according to or based upon the anatomy of the patient and/or of the patient population in consideration. The tibial component 110 may be made of a biocompatible material including, but not limited to, cobalt-chromium (Co-Cr), titanium, stainless steel, etc. In an embodiment, the tibial component 110 is made of cobalt-chromium (Co-Cr).
[32] Figs. 3A – 3D depict the tibial liner 130, according to an embodiment of the present disclosure. The tibial liner 130 replaces the natural cartilage tissues and provides an articulating surface to a femoral component of the knee prosthesis. The tibial liner 130 facilitates smooth movement within the joint, mimicking the natural gliding motion of a healthy knee cartilage. In an embodiment, the tibial liner 130 is used to replace one half of the natural tibial joint.
[33] In an embodiment, the tibial liner 130 has a D-shape, though it may have any other suitable shape. The tibial liner 130 includes a top surface 130a, and a bottom surface 130b. The top surface 130a of the tibial liner 130 is configured to articulate with the femoral condyles and/or the femoral component of the knee prosthesis. The bottom surface 130b mates with the base 111a of the tibial component 110.
[34] In an embodiment, the tibial liner 130 includes a top portion 131 and a bottom portion 133. The bottom portion 133 of the tibial liner 130 is configured to fit within the cavity 111 of the tibial component 110. The bottom portion 133 is shaped according to the shape of the cavity 111 such that the bottom portion 133 fits in the cavity 111 snugly and an outer edge of the bottom portion 133 mates with inner surface 115 of the wall 120. In an embodiment, the outer edge of the bottom portion 133 includes a carved section 133a carved in a shape corresponding to the shape of the inner surface 115 of the wall 120. The carved section 133a (shown in Fig. 3C) mates with the inner surface 115 of the wall 120.
[35] The bottom portion 133 includes a plurality of tabs provided on the outer edge of the bottom portion 133. Each of the plurality of tabs is configured to fit within a corresponding slot of the plurality of slots of the tibial component 110, thereby locking the tibial liner 130 with the tibial component 110. In an embodiment, the bottom portion 133 includes a first tab 131a and a second tab 131b.
[36] The first tab 131a is configured to fit within the first slot 115a of the tibial component 110. In an embodiment, the first tab 131a is positioned towards the anterior end 100a of the tibial prosthesis 100. The first tab 131a has a shape corresponding to the structure of the first slot 115a. In an embodiment, the first tab 131a has a rectangular shape with curved edges corresponding to the structure of the first slot 115a.
[37] The second tab 131b is configured to fit within the second slot 115b of the tibial component 110. In an embodiment, the second tab 131b is positioned towards the posterior end 100b of the tibial prosthesis 100. The second tab 131b may have a structure corresponding to the structure of the second slot 115b. In an embodiment, the second tab 131b has a dovetail structure complementary corresponding to the dovetail structure of the second slot 115b such that when the second tab 131b and the second slot 115b mate, they form a dovetail joint.
[38] Optionally, the outer edge includes one or more non-carved sections. Each of the one or more non-carved sections corresponds to a respective one of the one or more cut-outs in the wall 120 of the tibial component 110. Each non-carved section is configured to seat within the corresponding cut-out and aligns with an outer surface of the wall 120. In an embodiment, the outer edge of the bottom portion 133 includes a first non-carved section 133b1 and a second non-carved section 133b2 corresponding to the first cut-out 113a and the second cut-out 113b, respectively.
[39] The first non-carved section 133b1 sits within the first cut-out 113a and aligns with an outer surface of the wall 120. Similarly, the second non-carved section 133b2 sits within the second cut-out 113b and aligns with the outer surface of the wall 120.
[40] According to an embodiment, the bottom portion 133 includes a recess 133c towards the anterior end 100a. The recess 133c extends from the medial end 100c to the lateral end 100d of the tibial prosthesis 100, thus dividing the bottom portion 133 into two sections, namely, a first section 134a and a second section 134b. The first section 134a is positioned towards the anterior end 100a of the tibial prosthesis 100 and the second section 134b is positioned towards the posterior end 100b of the tibial prosthesis 100. In this case, the first section 134a has the first tab 131a and the second section 134b has the second tab 131b. The recess 133c forms an undulating surface 133d at the second section 134b of the bottom portion 133. The recess 133c provides space for the first tab 131a to bend towards the undulating surface 133d during the coupling of the tibial liner 130 with tibial component 110, which has been explained later.
[41] The dimensions of the tibial liner 130 may vary according to or based upon the anatomy of the patient and/or of patient population in consideration. The tibial liner 130 may be made of a biocompatible material including, but not limited to, Ultra-High Molecular Weight Polyethylene (UHMWPE) including vitamin E, high cross-linked polyethylene (HXLPE), ceramic, etc. In an embodiment, the tibial liner 130 is made of Ultra-High Molecular Weight Polyethylene (UHMWPE).
[42] An embodiment of coupling the tibial liner 130 with the tibial component 110 is now explained. The tibial liner 130 is aligned with and disposed over the tibial component 110. In an embodiment, the bottom portion 133 of the tibial liner 130 aligns with the cavity 111. The top surface 130a of the tibial liner 130 is then impacted (e.g., using a mallet). As a result, the bottom portion 133 of the tibial liner 130 moves into the cavity 111 of the tibial component 110. As the bottom portion 133 of the tibial liner 130 moves downwards, the second tab 131b of the tibial liner 130 mates with the second slot 115b of the tibial component 110, thus forming a dovetail joint towards the posterior end 100b of the tibial prosthesis 100. Upon alignment between the second tab 131b and the second slot 115b, the tibial liner 130 is to be pressed downwards at the anterior end 100a of the tibial prosthesis 100. When the tibial liner 130 is pressed, the first tab 131a interacts with the chamfered face 117 and slides over it. Upon gliding, the first tab 131a bends within the recess 133c, towards the undulating surface 133d. When the tibial liner 130 is pressed further, the first tab 131a seats within the first slot 115a, in the wall 120 of the tibial component 110 and a surface 134c of the second section 134b (shown in Fig 3B) mates with a section 117a of the inner surface 115 (i.e., a portion between the first slot 115a and the chamfered face 117,as shown in Fig. 2B), thus creating an interference lock between the tibial liner 130 and the tibial component 110, towards the anterior end 100a of the tibial prosthesis 100, thereby securely locking the tibial component 110 and the tibial liner 130 together. The locking mechanism helps to prevent any relative movement between the tibial liner 130 and the tibial component 110. The tibial component 110 and the tibial liner 130 are securely locked which eliminates any chances of dislocation or loosening.
[43] The present disclosure provides several advantages. For example, unlike the conventional prosthesis which are more prone to dislocation and loosening of the conventional tibial liner from the conventional tibial component, the proposed locking mechanism securely couples the tibial liner with the tibial component. The interference lock formed by the locking mechanism ensures a firm locking of the tibial liner with the tibial components. This prevents dislocation and loosening. This reduces the chances of failure and increases the life of the proposed tibial prosthesis. This improves the overall patient outcome.
[44] The scope of the invention is only limited by the appended patent claims. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the teachings of the present invention is/are used. ,CLAIMS:WE CLAIM
1. A tibial prosthesis (100) comprising:
a. a tibial component (110) comprising:
i. a wall (120) provided along a periphery of a base (111a) of the tibial component (110), the wall (120) defining a cavity (111); and
ii. a plurality of slots provided on an inner surface (115) of the wall (120); and
b. a tibial liner (130) comprising a top portion (131) and a bottom portion (133) configured to fit within the cavity (111), the bottom portion (133) comprising a plurality of tabs provided on an outer edge of the bottom portion (133), each of the plurality of tabs is configured to fit within a corresponding slot of the plurality of slots of the tibial component (110), thereby locking the tibial liner (130) with the tibial component (110).
2. The tibial prosthesis (100) as claimed in claim 1, wherein:
a. the plurality of slots of the tibial component (110) comprises:
i. a first slot (115a) provided towards an anterior end (100a) of the tibial prosthesis (100); and
ii. a second slot (115b) provided towards a posterior end (100b) of the tibial prosthesis (100); and
b. the plurality of tabs of the tibial liner (130) comprises:
i. a first tab (131a) configured to fit within the first slot (115a); and
ii. a second tab (131b) configured to fit within the second slot (115b).
3. The tibial prosthesis (100) as claimed in claim 2, wherein the first tab (131a) and the first slot (115a) have a rectangular shape, forming an interference lock therebetween.
4. The tibial prosthesis (100) as claimed in claim 2, wherein the second tab (131b) and the second slot (115b) have complementary dovetail structures, forming a dovetail joint therebetween.
5. The tibial prothesis (100) as claimed in claim 2, wherein the bottom portion (133) of the tibial component (110) comprises a recess (133c) provided towards the anterior end (100a) of the tibial prosthesis (100) and extending between a lateral end (100d) and a medial end (100c) of the tibial prosthesis (100), the recess (133c) dividing the bottom portion (133) into a first section (134a) having the first tab (131a) and a second section (134b) having the second tab (131b).
6. The tibial prosthesis (100) as claimed in claim 1, wherein the base (111a) of the tibial component (110) mates with a bottom surface (130b) of the tibial liner (130).
7. The tibial prosthesis (100) as claimed in claim 1, wherein the outer edge of the bottom portion (133) of the tibial liner (130) comprises a carved section (133a) configured to mate with the inner surface (115) of the wall (120).
8. The tibial prosthesis (100) as claimed in claim 1, wherein the wall (120) of the tibial component (110) comprises one or more cut-outs (113a, 113b), each cut-out (113a, 113b) is configured to receive a corresponding non-carved section (133b1, 133b2) of the tibial liner (130).
9. The tibial prosthesis (100) as claimed in claim 8, wherein the outer edge of the bottom portion (133) of the tibial liner (130) comprises one or more non-carved sections (133b1, 133b2), each non-carved section (133b1, 133b2) configured to seat within a respective cut-out (113a, 113b) and align with an outer surface of the wall (120).
10. The tibial prosthesis (100) as claimed in claim 8, wherein the one or more cut-outs comprises a first cut-out (113a) and a second cut-out (113b) provided opposite to each other towards the anterior end (100a) of the tibial prosthesis (100).
11. The tibial prosthesis (100) as claimed in claim 1, wherein the tibial component (110) is provided with at least one of: a keel (119) or one or more pegs.
12. The tibial prosthesis (100) as claimed in claim 1, wherein the tibial liner (130) comprises a top surface (130a) configured to articulate with one of: a femoral condyle or a femoral component of a knee prosthesis.
13. The tibial prosthesis (100) as claimed in claim 1, wherein the wall (120) includes one or more chamfered faces (117) on an interior edge of the wall (120).