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, namely, 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] Additionally, conventional tibial liners are impacted over the tibial component to create a proper fit between the two. However, impacting involves several risks, such as, damage to tibial liners, improper alignment, tissue damage, implant fracture, loosening, etc.
[7] Thus, there arises a need for a tibial prosthesis that overcomes the problems associated with the conventional prosthesis.
SUMMARY OF INVENTION
[8] Particular embodiments of the present disclosure are described herein below with reference to the accompanying drawings; however, it is to be understood that the disclosed embodiments are mere examples of the disclosure, which may be embodied in various forms. Well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure.
[9] The present disclosure relates to a tibial prosthesis. In an embodiment, the tibial prosthesis includes a tibial component, a tibial liner and a locking member. In an embodiment, the tibial component includes a wall provided along a periphery of a base of the tibial component. The wall defines a cavity. A first hole extends from an outer surface of the wall into the cavity. The tibial liner includes a protrusion provided on a bottom surface. The protrusion is configured to reside within the cavity of the tibial component. The protrusion includes a second hole aligned with the first hole of the tibial component. The locking member includes a first portion and a second portion. The first portion and the second portion are configured to be disposed within the first hole of the tibial component and the second hole of the tibial liner, respectively, thereby locking the tibial liner with the tibial component.
BRIEF DESCRIPTION OF DRAWINGS
[10] 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.
[11] Fig. 1a depicts a cross sectional view of a tibial prosthesis 100, in accordance with an embodiment of the present disclosure.
[12] Fig. 1b depicts an exploded view of the tibial prosthesis 100, in accordance with an embodiment of the present disclosure.
[13] Fig. 2a depicts a perspective view of a tibial component 110 of the tibial prosthesis 100, in accordance with an embodiment of the present disclosure.
[14] Fig. 2b – Fig. 2c depict perspective top views of the tibial component 110 of the tibial prosthesis 100, according to an embodiment of the present disclosure.
[15] Fig. 2d depicts a perspective bottom view of the tibial component 110 of the tibial prosthesis 100, according to an embodiment of the present disclosure.
[16] Fig. 3 depicts a perspective view of a locking member 120 of the tibial prosthesis 100, in accordance with an embodiment of the present disclosure.
[17] Fig. 4a depicts a perspective view of a tibial liner 130 of the tibial prosthesis 100, in accordance with an embodiment of the present disclosure.
[18] Fig. 4b depicts a perspective bottom view of the tibial liner 130 from an anterior end 100a of the tibial prosthesis 100, according to an embodiment of the present disclosure.
[19] Fig. 4c depicts a perspective bottom view of the tibial liner 130 from a posterior end 100b of the tibial prosthesis 100, according to an embodiment of the present disclosure.
DETAILED DESCRIPTION
[20] 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.
[21] 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.
[22] 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.
[23] 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.
[24] The present disclosure discloses a tibial prosthesis. The tibial prosthesis of present disclosure includes a tibial component, a locking member and a tibial liner. The tibial component is securely coupled with the tibial liner using the locking member. This 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. Also, the proposed tibial liner need not to be impacted like conventional tibial prosthesis while coupling with the tibial component. The proposed tibial liner can be placed within the tibial component and can be locked using the locking member. This minimizes the failure chances of the tibial prosthesis due to the impacting and improves patient outcome.
[25] Referring to figures, Fig. 1a depicts a cross sectional view of an assembled tibial prosthesis 100 and Fig. 1b depicts an exploded 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.
[26] 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.
[27] The tibial prosthesis 100 includes a tibial component 110, at least one locking member 120 and a tibial liner 130. The tibial component 110 is coupled to the tibial liner 130 with the help of the at least locking member 120. The present disclosure has been explained with the tibial prosthesis 100 having one locking member 120. It should not be considered as limiting, and the tibial prosthesis 100 may have more than one locking member 120. The tibial prosthesis 100 includes an anterior end 100a and a posterior end 100b. The anterior end 100a and the posterior end 100b of the tibial prosthesis 100 are designed to align towards the anterior side and posterior side of the tibial bone, respectively.
[28] 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.
[29] Figs. 2a – 2d depict various views of 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.
[30] 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 110a provided along a periphery of the base 111a. In an embodiment, the wall 110a includes a chamfered face 110b having a chamfered cut towards the anterior end 100a of the tibial prosthesis 100. The chamfered cut helps to enhance the engagement between the tibial component 110 and the tibial liner 130, ensuring stability and reducing the risk of movement or misalignment during usage. In another embodiment, the wall 110a may not have the chamfered face 110b.
[31] The wall 110a of the tibial component 110 defines a cavity 111. The cavity 111 is configured to receive a portion of the tibial liner 130 (explained later). The wall 110a includes a predefined shape and predefined dimensions. The predefined dimensions and 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 has a D-shape, though it may have any other desired shape (e.g., elliptical, square, rectangular, hexagonal, etc.).
[32] The wall 110a includes an inner surface 115. The inner surface 115 of the wall 110a may be sculpted asymmetrically and have a plurality of sides. In an exemplary embodiment, the inner surface 115 includes six sides namely, a first wall side 115a, a second wall side 115b, a third wall side 115c, a fourth wall side 115d, a fifth wall side 115e and a sixth wall side 115f. In an exemplary embodiment, the inner surface 115 has a non-uniform structure, though it may have a uniform structure.
[33] In an embodiment, the second wall side 115b and the third wall side 115c are provided towards the posterior end 100b of the tibial prosthesis 100. The fifth wall side 115e and the sixth wall side 115f are provided towards the anterior end 100a of the tibial prosthesis 100. In an embodiment, the structural geometries of the first wall side 115a, the second wall side 115b, the third wall side 115c, the fourth wall side 115d, the fifth wall side 115e and the sixth wall side 115f are asymmetric with respect to each together, thus forming the non-uniform structure. The asymmetric geometry of the wall 110a provides an effective locking between the tibial component 110 and the tibial liner 130, which has been explained later.
[34] The wall 110a may include one or more first dovetail structures provided on the inner surface 115 of the wall 110a. In an embodiment, the wall 110a includes one first dovetail structure provided towards the posterior end 100b of the tibial prosthesis 100.
[35] In an embodiment, the first wall side 115a includes a straight portion followed by a curved portion. The curved portion of the first wall side 115a is followed by the second wall side 115b. The second wall side 115b includes a straight portion followed by a curved portion. The curved portion of the second wall side 115b is followed by the third wall side 115c. The third wall side 115c includes a slanted portion followed by a curved portion. At least a portion of one or more of the first wall side 115a, the second wall side 115b, the third wall side 115c are angled at a predefined angel with respect to the base 111a of the tibial component 110 to form the first dovetail structure. In an embodiment, at least a portion of one or more of: the first wall side 115a, the second wall side 115b or the third wall side 115c are angled relative to the base 111a of the tibial component 110 to form the first dovetail structure. For example, the curved portion of the first wall side 115a, the straight and curved portions of the second wall side 115b and the slanted and curved portion of the third wall side 115c, towards the posterior end 100b, are carved angularly relative to the base 111a of the tibial component 110 at the predefined angle, thus forming the first dovetail structure. The predefined angle may vary depending upon the portion of the tibial liner 130 received by the cavity 111. The first dovetail structure helps in providing a secure coupling between the tibial component 110 and the tibial liner 130.
[36] The curved portion of the third wall side 115c is followed by the fourth wall side 115d. The fourth wall side 115d includes a straight portion followed by a curved portion. The curved portion of the fourth wall side 115d is followed by the fifth wall side 115e. The fifth wall side 115e includes a straight portion followed by a curved portion. The curved portion of the fifth wall side 115e is followed by the sixth wall side 115f. The sixth wall side 115f includes a straight portion followed by a curved portion. The curved portion of the sixth wall side 115f is followed by the straight portion of the first wall side 115a.
[37] The first wall side 115a, the second wall side 115b, the third wall side 115c, the fourth wall side 115d, the fifth wall side 115e and the sixth wall side 115f are configured to mate with a corresponding portion provided on the tibial liner 130, which has been explained later.
[38] The tibial component 110 includes at least one first hole 113 provided towards an anterior end 100a of the tibial prosthesis 100. In an embodiment, the first hole 113 is provided on the sixth wall side 115f of the wall 110a (e.g., on the chamfered face 110b of the wall 110a) and extends from an outer surface of wall 110a into the cavity 111. In other words, the first hole 113 is a through-hole. The first hole 113 is configured to engage with or receive a portion of the locking member 120 (explained later). Though in the depicted embodiment, the tibial component 110 includes one first hole 113, the tibial component 110 may be provided with more than one first hole 113, each configured receive a portion of a respective locking member 120.
[39] In an exemplary embodiment, the diameter of the first hole 113 corresponds to the diameter of the locking member 120 (explained later). At least a partial length of an inner surface of the first hole 113 includes first internal threads (not shown). In an exemplary embodiment, the first internal threads are provided for an entire length of the inner surface of the first hole 113. The internal threads provide additional stability and allow the locking member 120 to be securely anchored within the tibial component 110, reducing the risk of loosening over time.
[40] In an embodiment, the tibial component 110 includes one or more pegs (for example, pegs 117a and 117b) and/or a keel 117c integrally extending from a bottom surface 110c of the tibial component 110 as shown in Fig 2c. The one or more pegs (the pegs 117a and 117b) and the keel 117c ensure a secured coupling of the tibial component 110 with the tibial bone, which prevents dislocation/de-attachments of the tibial component 110 from the tibial bone. The one or more pegs (e.g., the pegs 117a and 117b) and the keel 117c may have any suitable shape based upon the requirements. In an embodiment, the pegs 117a and 117b are hour-glass shaped protrusions for improved cement interlock. The pegs (117a, 117b) provide rotational stability to the tibial component 110. In an embodiment, the keel 117c has a fish fin-like shape with a smooth surface. The smooth surface of the keel 117c prevents damages to the surrounding tissues post-implantation.
[41] The bottom surface 110c of the tibial component 110 includes a plurality of the sections 117d as shown in Fig. 2d. The sections 117d are spread across at least a portion of the bottom surface 110c of the tibial component 110. In an exemplary embodiment, the tibial component 110 is provided with five sections 117d spread across the entire bottom surface 110c of tibial component 110.The sections 117d help in enhancing the coupling between the tibial component 110 and the tibia, thereby improving fixation and stability post- implantation.
[42] 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).
[43] Fig. 3 depicts the locking member 120, according to an embodiment of the present disclosure. The locking member 120 is configured to securely lock the tibial component 110 with the tibial liner 130. The locking member 120 ensures the stability and longevity of the coupling of the tibial component 110 and the tibial liner 130 and thus, prevents loosening of the tibial liner 130. The locking member 120 is configured to be partially disposed within the first hole 113 of the tibial component 110. In an embodiment, the locking member 120 has a cylindrical shape, though it may have any other shape (e.g., rectangular, oval, square, frustum, triangular, etc.).
[44] In an embodiment, the locking member 120 includes a first portion 121a and a second portion 121b. The first portion 121a is configured to be disposed within the first hole 113 of the tibial component 110 and the second portion 121b is configured to be disposed within the tibial liner 130, thereby locking the tibial liner 130 with the tibial component 110 (explained later).
[45] The first portion 121a may be at least partially threaded, having first threads 123 provided on an outer surface of the first portion 121a for at least a partial length of the first portion 121a. In an embodiment, the first portion 121a includes the first threads 123 provided on the entire length of the first portion 121a. The first threads 123 are complementary to and configured to engage with the first internal threads of the first hole 113 provided in the tibial component 110. The shape and dimensions of the first portion 121a matches the dimensions of the first hole 113.
[46] The second portion 121b may be smooth, partially threaded or fully threaded. In an embodiment, the outer surface 121b1 of the second portion 121b is smooth. In another embodiment, the second portion 121b has second threads provided at least partially on an outer surface 121b1.
[47] Additionally, or optionally, the first portion 121a of the locking member 120 includes a face 121c having a groove 121c1. In an embodiment, the face 121c has a concave surface, facilitating proper insertion of the locking member 120 in the first hole 113. The groove 121c1 enables a user to hold the locking member 120 (for example, using a plier).
[48] The locking member 120 may be made of a biocompatible material including, but not limited to, cobalt-chromium (Co-Cr), titanium, stainless steel, etc. In an embodiment, the locking member 120 is made of cobalt-chromium (Co-Cr).
[49] Figs. 4a – 4c depict various views of 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.
[50] In an embodiment, the tibial liner 130 has a D-shape, though it may have any other suitable shape. The tibial liner 130 includes the protrusion 131 provided on a bottom surface 130a (shown in Figs. 4b – 4c) of the tibial liner 130. The protrusion 131 forms an integral structure with the tibial liner 130, for example, the protrusion 131 may be extruded from the bottom surface 130a of the tibial liner 130. A top surface 130b of the tibial liner 130 is configured to articulate with the femoral condyles and/or the femoral component of the knee prosthesis.
[51] The protrusion 131 is configured to fit (or reside) within the cavity 111 of the tibial component 110. The shape and dimensions of the protrusion 131 correspond to the shape and dimensions of the cavity 111 of the tibial component 110, so that the protrusion 131 can snugly fit within the cavity 111.
[52] The protrusion 131 may include a plurality of sides. In an exemplary embodiment, the protrusion 131 includes six sides, namely, a first side 131b1, a second side 131b2, a third side 131b3, a fourth side 131b4, a fifth side 131b5 and a sixth side 131b6. Each side (131b1-131b6) of the protrusion 131 of the tibial liner 130 is designed to align and mate with a corresponding wall side (115a-115f) of the inner surface 115 of the wall 110a. In an exemplary embodiment, the protrusion 131 has a non-uniform structure, though it may have a uniform structure complementary to the inner surface 115 of the tibial component 110.
[53] In an embodiment, the second side 131b2 and the third side 131b3 are provided towards the posterior end 100b of the tibial prosthesis 100. Further, the fifth side 131b5 and the sixth side 131b6 are positioned towards the anterior end 100a of the tibial prosthesis 100. The structural geometries of the first sides 131b1 to 131b2 are asymmetric with respect to each other, thus forming the non-uniform structure and complementary to the wall sides 115a-115f of the inner surface 115. The asymmetric geometry of the protrusion 131 complements the non-uniform structure of the wall sides 115a-115f of the cavity 111, ensuring an effective and secure locking mechanism between the tibial liner 130 and tibial component 110. In an embodiment, the first side 131b1, the second side 131b2, the third side 131b3, the fourth side 131b4, the fifth side 131b5 and the sixth side 131b6 engage or mate with the first wall side 115a, the second wall side 115b, the third wall side 115c, the fourth wall side 115d, the fifth wall side 115e and the sixth wall side 115f, respectively.
[54] The protrusion 131 may include one or more second dovetail structures 135. Each of the one or more second dovetail structures 135 is configured to engage with, and is complementary to, a corresponding one of the first dovetail structures of the wall 110a of the tibial component 110. In an embodiment, one second dovetail structure 135 is provided on an outer perimeter of the protrusion 131 towards the posterior end 100b of the tibial prosthesis 100. The second dovetail structure 135 may be a cut-out on the protrusion 131 towards the posterior end 100b of the tibial prosthesis 100. The second dovetail structure 135 interlocks with a corresponding first dovetail structure of the wall 110a, providing additional mechanical stability and preventing relative motion between the tibial liner 130 and the tibial component 110.
[55] In an embodiment, the first side 131b1 of the protrusion 131 includes a straight portion followed by a curved segment. The curved segment transitions smoothly into the second side 131b2. The second side 131b2 includes a straight portion followed by a curved segment. The curved portion of the second side 131b2 of the protrusion 131 is followed by the third side 131b3. The third side 131b3 includes a slant portion followed by a curved portion. At least a portion of one or more of the first side 131b1, the second side 131b2 and the third side 131b3 may be carved angularly at a predefined angle with respect to the bottom surface 130a of the tibial liner 130, to form the second dovetail structure 135. In an exemplary embodiment, the curved portions of the first side 131b1, the straight portion and the curved segment of the second side 131b2, and the slant portion and curved portion of the third side 131b3, provided towards the posterior end 100b of the tibial liner 130, are carved angularly at the predefined angle, thus forming the second dovetail structure 135. The second dovetail structure 135 aligns with the first dovetail structure provided on the inner surface 115 of the cavity 111.
[56] The angular carving of the protrusion 131 matches the predefined angle of the inner surface 115 of the cavity 111, ensuring precise engagement with the first dovetail structure of the tibial component 110. The second dovetail structure 135 of the protrusion 131 allows it to securely interlock with the corresponding first dovetail structure of the inner surface 115 of the tibial component 110, thus forming a dovetail joint. The complementary angles and curvature between the sides of the protrusion 131 and the inner surface 115 of the wall 110a of the cavity 111 provide a robust coupling mechanism, preventing movement or loosening under operational loads.
[57] The curved portion of the third side 131b3 of the protrusion 131 is followed by the fourth side 131b4. The fourth side 131b4 includes a straight portion followed by a curved portion. The curved portion of the fourth side 131b4 transitions seamlessly into the fifth side 131b5. The fifth side 131b5 includes a slant portion succeeded by a curved portion. The curved portion of the fifth side 131b5 then transitions into the sixth side 131b6. The sixth side 131b6 includes a straight portion followed by a curved portion, which then connects to the straight portion of the first side 131b1, completing the structure of the protrusion 131.
[58] The first side 131b1, the second side 131b2, the third side 131b3, the fourth side 131b4, the fifth side 131b5, and the sixth side 131b6 of the protrusion 131 are designed to mate precisely with the corresponding wall sides 115a, 115b, 115c, 115d, 115e, and 115f of the cavity 111, respectively. The alignment and complementary geometry ensure a snug and stable fit between the tibial liner 130 and the tibial component 110, enhancing the structural integrity and stability of the tibial prosthesis 100.
[59] The protrusion 131 has at least one second hole 133 provided on an anterior side of the protrusions 131. In an embodiment, one second hole 133 is provided on the sixth side 131b6 of the protrusion 131 such that the second hole 133 aligns with the first hole 113 of the tibial component 110 when the tibial liner 130 and the tibial component 110 are coupled together. The second hole 133 extends into the protrusion 131 for a pre-defined length. The second hole 133 is configured to receive the second portion 121b of the locking member 120. In other words, the second portion 121b of the locking member 120 is configured to be disposed within the second hole 133. The second hole 133 may be smooth, partially threaded or fully threaded, complementary to the second portion 121b. In one embodiment, the second hole 133 has a smooth inner surface configured to mate with a smooth outer surface 121b1 of the locking member 120. In another embodiment, at least a partial length of the second hole 133 is provided with second internal threads on an inner surface. The second internal threads are configured to engage with second threads provided on the second portion 121b. Thus, the first portion 121a of the locking member 120 is disposed within the first hole 113 of the tibial component 110 and the second portion 121b of the locking member 120 is disposed within the second hole 133 of the tibial liner 130. As a result, the locking member 120 locks the tibial liner 130 with the tibial component 110. In an embodiment, the second hole 133 has the shape and dimensions matching that of the second portion 121b so that the second portion 121b snugly fits within the second hole 133. In an embodiment, the second hole 133 is circular, with dimensions matching those of the second portion 121b, providing a precise and stable engagement. Though the depicted embodiment shows one second hole 133 provided on the protrusion 131, it should be understood that the protrusion 131 may be provided with more than one second hole 133, each receiving the second portion 121b of the respective locking member 120.
[60] ¬¬¬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 high cross-linked polyethylene (HXLPE).
[61] 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. For example, the protrusion 131 aligns with the cavity 111. The top surface 130b of the tibial liner 130 is pushed down gently. As a result, the protrusion 131 moves into the cavity 111. Further, a bottom surface 131a of the protrusion 131 mates with the base 111a of the cavity 111. In an embodiment, the second dovetail structure 135 of the protrusion 131 in the tibial liner 130 mates with the corresponding first dovetail structure provided on the inner surface 115 of the wall 110a in the tibial component 110, to form a dovetail joint. Thus, the tibial liner 130 is assembled with the tibial component 110 via a press-fit mechanism. Further, to couple the locking member 120 with the tibial component 110 and the tibial liner 130, the locking member 120 is gripped via the groove 121c1 using a suitable instrument so that it can be easily inserted through the first hole 113. The second portion 121b is inserted into the second hole 133. The first threads 123 of the first portion 121a are mutually locked with the threads of the first hole 113. Once the second portion 121b fits into the second hole 133, and the first portion 121a fits within the first hole 113, the instrument is removed. The second portion 121b and an inner surface of the second hole 133 form an interference lock and the first portion 121a is securely threaded with the first hole 113 of the tibial component 110. This, interference lock and the threaded coupling ensures that the tibial component 110 and the tibial liner 130 do not move relative to each other. Thus, the tibial component 110 and the tibial liner 130 are securely locked with each other via the locking member 120 and any chances of dislocation or loosening are eliminated. A cross sectional view of assembled tibial prosthesis 100 is depicted in Fig. 1.
[62] 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 tibial liner in the present disclosure is securely coupled to the tibial component using the locking member. The locking member ensures a firm locking of the tibial liner with the tibial component. This prevents dislocation and loosening. This reduces the chances of failure and increases the life of the proposed tibial prosthesis. Further, the proposed tibial liner does not need to be impacted over the proposed tibial component, which in turns reduces the risk of damage to tibial liners, improper alignment, tissue damage, implant fracture, loosening, etc. Thus, the proposed tibial prosthesis improves the overall patient outcome.
[63] 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 (110a) provided along a periphery of a base (111a) of the tibial component (110), the wall (110a) defining a cavity (111); and
ii. a first hole (113) extending from an outer surface of the wall (110a) into the cavity (111);
b. a tibial liner (130) comprising a protrusion (131) provided on a bottom surface (130a) of the tibial liner (130) and configured to reside within the cavity (111) of the tibial component (110), the protrusion (131) comprising a second hole (133) aligned with the first hole (113) of the tibial component (110); and
c. a locking member (120) comprising:
i. a first portion (121a) configured to be disposed within the first hole (113) of the tibial component (110); and
ii. a second portion (121b) configured to be disposed within the second hole (133) of the tibial liner (130), thereby locking the tibial liner (130) with the tibial component (110).
2. The tibial prosthesis (100) as claimed in claim 1, wherein the first portion (121a) comprises first threads (123) disposed on an outer surface of the first portion (121a) for at least a partial length of the first portion (121a), wherein the first hole (113) of the tibial component (110) comprises first internal threads provided on an inner surface of the first hole (113) for at least a partial length of the first hole (113) and configured to engage with the first threads (123) of the first portion (121a).
3. The tibial prosthesis (100) as claimed in claim 1, wherein the second portion (121b) comprises second threads provided at least partially on an outer surface (121b1) of the second portion (121b), wherein the second hole (133) of the tibial liner (130) comprises second internal threads provided at least partially on an inner surface of the second hole (133) and configured to engage with the second threads of the second portion (121b).
4. The tibial prosthesis (100) as claimed in claim 1, wherein the second portion (121b) has a smooth outer surface (121b1) configured to mate with a smooth inner surface of the second hole (133).
5. The tibial prosthesis (100) as claimed in claim 1, wherein the first portion (121a) of the locking member (120) includes a face (121c) having a groove (121c1).
6. The tibial prosthesis (100) as claimed in claim 1, wherein:
a. the wall (110a) of the tibial component (110) comprises one or more first dovetail structures provided on an inner surface (115); and
b. the protrusion (131) of the tibial liner (130) comprises one or more second dovetail structure (135) on an outer perimeter of the protrusion (131), each of the one or more second dovetail structure (135) of the protrusions (131) is configured to mate with a corresponding first dovetail structure of the one or more first dovetail structures provided on the wall (110a) of the tibial component (110), forming a dovetail joint.
7. The tibial prosthesis (100) as claimed in claim 6, wherein:
a. the inner surface (115) of the wall (110a) comprises a first wall side (115a), a second wall side (115b) and a third wall side (115c), at least a portion of one or more of: the first wall side (115a), the second wall side (115b) or the third wall side (115c) is angled relative to the base (111a) of the tibial component (110), to form the first dovetail structure; and
b. the protrusion (131) of the tibial liner (130) comprises a first side (131b1), a second side (131b2) and a third side (131b3), at least a portion of one or more of: the first side (131b1), the second side (131b2) and a third side (131b3) is angled relative to the bottom surface (130a) of the tibial liner 130, to form the second dovetail structure (135).
8. The tibial prosthesis (100) as claimed in claim 1, wherein the tibial component (110) is provided with at least one keel (117c) on a bottom surface (110c) of the tibial component (110).
9. The tibial prosthesis (100) as claimed in claim 1, wherein the tibial component (110) is provided with one or more pegs (117a, 117b) on a bottom surface (110c) of the tibial component (110).
10. The tibial prosthesis (100) as claimed in claim 1, wherein the tibial component (110) is provided with one or more sections (117d) on a bottom surface (110c) of the tibial component (110).