Description: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:
KNEE IMPLANT
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 an orthopedic implant. More particularly, the present disclosure relates to a knee implant.
BACKGROUND OF INVENTION
[2] Osteoarthritis is a degenerative disease in which tissue/cartilage between the knee joints breaks over time which leads to joint pain, and stiffness. Patients with knee osteoarthritis undergo a Total Knee Replacement (TKR), also called as a Total Knee Arthroplasty (TKA), procedure. In this procedure, damaged or diseased parts of the knee joint are replaced with artificial parts (prosthesis).
[3] A typical knee prosthesis (or implant) includes a femoral component, a tibial base plate, and a tibial liner. The tibial base plate is affixed with the tibia of a patient and is coupled with the tibial liner. The tibial liner provides an articulating surface for the femoral component. Depending upon the degree of damage of the knee joint, different types of tibial knee liners are implanted. For example, during a primary knee replacement surgery, a cruciate retaining tibial liner is used whereas during a revision surgery or where the patient has a severe damage, a hinge tibial liner is used. Further, the size of the tibial liners also varies depending upon the patient’s anatomy.
[4] Conventionally, separate tibial base plates are used for different types and sizes of tibial liners. In other words, a conventional tibial base plate can be coupled only with a specific type and size of a tibial liner. This requires manufacturing tibial base plates in different types and sizes, which increases manufacturing complexity. Additionally, a tibial liner of each size requires a separate tibial base plate of an appropriate size. Thus, conventional implants have higher size matrix. Further, medical establishments need to stock several tibial base plates to cater to different patients. This ultimately results in increased medical costs not just for the medical establishment but also for the patients.
[5] Thus, there arises a need for an implant that overcomes the problems associated with the conventional implants.
SUMMARY OF INVENTION
[6] 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.
[7] The present disclosure relates to an implant. In an embodiment, the implant includes a tibial base plate and a tibial liner. The tibial base plate includes a top surface, a bottom surface and a peripheral surface extending between the top surface and the bottom surface of the tibial base plate. The peripheral surface includes a first coupling structure extending for at least a partial length of the peripheral surface of the tibial base plate. The tibial liner includes a bottom face and a cavity provided on the bottom face of the tibial liner. The cavity includes a second coupling structure extending for at least a partial length of a periphery of the cavity. The second coupling structure is complementary to the first coupling structure and is configured to mate with the first coupling structure, thereby coupling the tibial liner with the tibial base plate.
BRIEF DESCRIPTION OF DRAWINGS
[8] 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.
[9] Fig. 1 depicts a front view of a tibial base plate 110, according to an embodiment of the present disclosure.
[10] Fig. 1a depicts a cross-sectional view of the tibial base plate 110, according to an embodiment of the present disclosure.
[11] Fig. 1b depicts a perspective view of the tibial base plate 110, according to an embodiment of the present disclosure.
[12] Fig. 1c depicts a top view of the tibial base plate 110, according to an embodiment of the present disclosure.
[13] Fig. 2 depicts a perspective view of a plug 120, according to an embodiment of the present disclosure.
[14] Fig. 3a depicts a front view of a tibial liner 130, according to an embodiment of a present disclosure.
[15] Fig. 3b depicts a cross-sectional view of the tibial liner 130, according to an embodiment of a present disclosure.
[16] Fig. 3c depicts an assembled view of an implant 100 including the tibial liner 130 and the tibial base plate 110, according to an embodiment of a present disclosure.
[17] Fig. 4a depicts a front view of a tibial liner 140, according to an embodiment of a present disclosure.
[18] Fig. 4b depicts a perspective view of the tibial liner 140, according to an embodiment of a present disclosure.
[19] Fig. 4c depicts an assembled view of an implant 200 including the tibial liner 140 and the tibial base plate 110, according to an embodiment of a present disclosure.
[20] Fig. 5a depicts a top perspective view of a tibial liner 150, according to an embodiment of a present disclosure.
[21] Fig. 5b depicts a bottom perspective view of the tibial liner 150, according to an embodiment of a present disclosure.
[22] Fig. 6a depicts a top perspective view of a tibial liner 160, according to an embodiment of a present disclosure.
[23] Fig. 6b depicts a bottom perspective view of the tibial liner 160, according to an embodiment of a present disclosure.
[24] Fig. 7a depicts a perspective view of a tumor cone 170, according to an embodiment of a present disclosure.
[25] Fig. 7b depicts a top view of the tumor cone 170, according to an embodiment of a present disclosure.
[26] Fig. 8 depicts a perspective view of a fastener 180, according to an embodiment of a present disclosure.
DETAILED DESCRIPTION OF THE DRAWINGS
[27] 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.
[28] 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.
[29] 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.
[30] 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.
[31] The present disclosure relates to a knee prosthesis (or implant). In an embodiment, the implant includes a tibial base plate and a tibial liner coupled to the tibial base plate. The tibial base plate is designed in such a way that the same tibial base plate can be assembled with a tibial liner of any size and/or type. Different types of tibial liners that can be coupled with the proposed tibial base plate, include, without limitation, a cruciate retaining (CR) tibial liner, a posterior stabilized (PS) liner, a hinge tibial liner and the like. Moreover, the proposed tibial base plate can also be coupled with a tumor cone used in a tumor surgery. Thus, the present disclosure obviates the need for manufacturing multiple tibial base plates for different types and sizes of tibial liners and the tumor cone. This reduces overall medical costs. Further, it also decreases inventory required during, for example, a TKA procedure, thereby reducing the complexity of the procedure, decreasing the procedure time and improving the efficiency of the procedure.
[32] Fig. 1 depicts a front view of an exemplary tibial base plate 110, according to an embodiment. Fig. 1a depicts a cross-sectional view and Fig. 1b depicts a perspective view of the tibial base plate 110. The tibial base plate 110 is used in a knee prosthesis or implant. The tibial base plate 110 replaces the damaged or diseased portion of the tibia in patients suffering from severe knee arthritis or injury. The tibial base plate 110 extends between a proximal end 110a and a distal end 110b, thereby defining a length.
[33] The tibial base plate 110 may be made of a material including, but not limited to, titanium, cobalt chromium, Stainless steel 316 (SS316), etc. In an exemplary embodiment, the tibial base plate 110 is made of a Titanium alloy. The dimensions of the tibial base plate 110 may vary according to or based upon the anatomy of the patient and/or of the patient population in consideration. The tibial base plate 110 has a pre-defined shape such as, without limitation, rectangular, square, D-shape, oval, etc. In an exemplary embodiment, the tibial base plate 110 has a D shape.
[34] The tibial base plate 110 has a top surface 111a, a bottom surface 111b and a peripheral surface 112. The top surface 111a is situated at the proximal end 110a and the bottom surface 111b is situated towards the distal end 110b. The peripheral surface 112 extends between the top surface 111a and the bottom surface 111b. In an embodiment, the tibial base plate 110 includes a first coupling structure 112a provided circumferentially. The first coupling structure 112a extends for at least a partial length of the peripheral surface 112. In the depicted embodiment, the first coupling structure 112a extends for the entire length of the peripheral surface 112. The first coupling structure 112a has a pre-defined cross-sectional shape such as, without limitation, square, rectangular, semi-circular, triangular, dovetail, oval, etc. In an embodiment, the first coupling structure 112a is a slot having a rectangular cross-section. The first coupling structure 112a is used to couple the tibial base plate 110 with a variety of tibial liners as explained later. In an embodiment, the first coupling structure 112a is configured to mate with a second coupling structure of a tibial liner.
[35] In an embodiment, the tibial base plate 110 includes a keel 117. The keel 117 ensures a secure coupling of the tibial base plate 110 with the tibia and provides stability to the implant. The keel 117 extends from the bottom surface 111b towards the distal end 110b. The keel 117 may be suitably positioned. In the depicted embodiment, the keel 117 is provided centrally on the bottom surface 111b. The keel 117 has a pre-defined shape such as, without limitation, cylindrical, rectangular, oval, etc. In an example implementation, the keel 117 has a cylindrical body and two triangular wings extending laterally from the body. It should be understood that the keel 117 may have any structure based upon requirements. The keel 117 may be made of a material such as, without limitation, titanium, cobalt chromium, stainless steel (e.g., SS316), etc. In an example implementation, the keel 117 is made of titanium. Though in the depicted embodiment, the keel 117 and the tibial base plate 110 form an integrated structure, in an alternate embodiment, the keel 117 and the tibial base plate 110 may be separate components coupled together using any suitable coupling technique. The dimensions of the keel 117 may vary according to or based upon the anatomy of the patient and/or of the patient population in consideration.
[36] The keel 117 has a distal face 117a. In an embodiment, the keel 117 has a tubular structure and includes an aperture 115 defining an inner surface 117b. The aperture 115 extends from the distal end 110b towards the proximal end 110a for at least a partial length of the keel 117. In the depicted embodiment, the aperture 115 extends for a partial length of the keel 117.
[37] In an embodiment, the tibial base plate 110 includes a hole 119 provided centrally on the top surface 111a (depicted in Figs. 1a and 1c). The hole 119 extends along a longitudinal axis of the tibial base plate 110 from the top surface 111a. In an embodiment, the hole 119 extends into the aperture 115 of the keel 117. The hole 119 is generally cylindrical. A proximal portion of the hole 119 has an inner surface 113 (shown in Fig. 1a). The proximal portion has a pre-defined shape, for example, a frustum shape as depicted in Fig. 1a.
[38] The keel 117 may be coupled with a tibial stem (not shown) of a knee prosthesis (or implant). For example, the aperture 115 is coupled with a portion of the tibial stem. In some situations, for example, primary surgeries, a tibial stem may not be required. In such cases, a plug may be provided to plug the aperture 115. Fig. 2 depicts an exemplary plug 120. The plug 120 has a proximal end 120a and a distal end 120b. The plug 120 is configured to close the aperture 115 of the keel 117. The plug 120 includes a proximal portion 120c situated towards the proximal end 120a and a distal portion 120d situated towards the distal end 120b. In an embodiment, the proximal portion 120c and the distal portion 120d are generally cylindrical having the same or different diameters. In the depicted embodiment, the distal portion 120d has a larger diameter than the proximal portion 120c. The diameter of the distal portion 120d corresponds to the diameter of the aperture 115 of the keel 117. The plug 120 is coupled to the keel 117 using, for example, a press-fit technique. The proximal portion 120c is inserted into the keel 117 from a distal end of the aperture 115 and press-fitted such that a second face 123 of the plug 120 is configured to mate with the inner surface 117b of the keel 117 and a first face 121 is configured to be flush with the distal face 117a of the keel 117. The plug 120 may be made of a material including, but not limited to, Ultra-High Molecular Weight Polyethylene (UHMWPE), Polymethyl methacrylate (PMMA), Highly cross-linked polyethylene (HXLPE) including Vitamin E, etc. In an exemplary embodiment, the plug 120 is made of Ultra-high Molecular Weight Polyethylene (UHMWPE).
[39] As explained earlier, the tibial base plate 110 can be coupled to tibial liners of various types and sizes. Examples of different types of tibial liners include, without limitation, cruciate retaining (CR) tibial liner, posterior stabilized (PS) tibial liner, hinge tibial liner, etc. Fig. 3a and Fig. 3b depict a front view and a cross-sectional view, respectively, of an exemplary tibial liner 130. The tibial liner 130 is coupled with the tibial base plate 110. In an embodiment, the tibial liner 130 is a CR tibial liner. The tibial liner 130 and the tibial base plate 110 form a part of a CR knee prosthesis (or implant). The tibial liner 130 replaces the natural cartilage tissues and provides an articulating surface to a femoral component (not shown) of a knee prosthesis. The tibial liner 130 facilitates smooth movement within the knee joint, mimicking the natural gliding motion of a healthy knee cartilage. The tibial liner 130 has a pre-defined shape such as, without limitation, rectangular, square, D-shaped, oval, etc. In an example implementation, the tibial liner 130 has a generally D shape. The tibial liner 130 may be made of a material including, but not limited to, Ultra-High Molecular Weight Polyethylene (UHMWPE), Polymethyl methacrylate (PMMA), Highly cross-linked polyethylene (HXLPE) including Vitamin E, etc. In an example implementation, the tibial liner 130 is made of Ultra-High Molecular Weight Polyethylene (UHMWPE). The dimensions of the tibial liner 130 may vary according to or based upon the anatomy of the patient and/or of the patient population in consideration.
[40] The tibial liner 130 has a proximal end 130a and a distal end 130b. The tibial liner 130 has a bottom face 131 situated towards the distal end 130b. The bottom face 131 mates with a surface of the tibia. In an embodiment, the tibial liner 130 includes a cavity 133 provided on the bottom face 131. The shape of the cavity 133 matches with the shape of the tibial base plate 110. In an embodiment, the cavity 133 includes a second coupling structure 135 provided at least partially along a periphery of the cavity 133. In an embodiment, the second coupling structure 135 extends along the entire periphery of the cavity 133. The second coupling structure 135 is configured to mate with the first coupling structure 112a. The second coupling structure 135 is complementary to the first coupling structure 112a. The second coupling structure 135 may have a pre-defined cross-sectional shape, such as, without limitation, rectangular, triangular, square, dovetail, etc. In an embodiment, the second coupling structure 135 is a rim having a rectangular cross-section. The cavity 133 has a face 137 configured to mate with the top surface 111a of the tibial base plate 110.
[41] To assemble the tibial base plate 110 and the tibial liner 130 together, the tibial liner 130 is disposed over and aligned with the tibial base plate 110 such that the top surface 111a and the peripheral surface 112 of the tibial base plate 110 align with the face 137 and the periphery of the cavity 133, respectively, of the tibial liner 130. The tibial base plate 110 and the tibial liner 130 are then pressed together for example, by impacting the tibial liner 130 using a mallet. The second coupling structure 135 of the tibial liner 130 mates with the first coupling structure 112a of the tibial base plate 110 creating a press-fit lock. This ensures that the tibial base plate 110 and the tibial liner 130 are coupled securely. An assembled view of an exemplary implant 100 including the tibial base plate 110 and the tibial liner 130 is illustrated in Fig. 3c.
[42] Fig. 4a and Fig. 4b depict a front view and a cross-sectional view, respectively, of an exemplary tibial liner 140. The tibial liner 140 is coupled with the tibial base plate 110. In an embodiment, the tibial liner 140 is a CR tibial liner. The tibial liner 140 has a similar structure to the tibial liner 130 except that the tibial liner 140 has a smaller size than the tibial liner 130. The tibial liner 140 may be used when a smaller size is desirable based upon the patient’s anatomy. The tibial liner 140 may be made of a material including, but not limited to, Ultra-High Molecular Weight Polyethylene (UHMWPE), Polymethyl methacrylate (PMMA), Highly cross-linked polyethylene (HXLPE) including Vitamin E, etc. In an example implementation, the tibial liner 140 is made of Ultra-High Molecular Weight Polyethylene (UHMWPE). The dimensions of the tibial liner 140 may vary according to or based upon the anatomy of the patient and/or of the patient population in consideration.
[43] The tibial liner 140 has a proximal end 140a and a distal end 140b. The tibial liner 140 has a bottom face 141 situated towards the distal end 140b. The bottom face 141 mates with a surface of the tibia. As can be seen, the bottom face 141 of the tibial liner 140 has a smaller width than the bottom face 131 of the tibial liner 130. In an embodiment, the tibial liner 140 includes a cavity 143 provided on the bottom face 141. The shape of the cavity 143 matches with the shape of the tibial base plate 110. In an embodiment, the cavity 143 includes a second coupling structure 145 provided at least partially along a periphery of the cavity 143. In an embodiment, the second coupling structure 145 extends along the entire periphery of the cavity 143. The second coupling structure 145 is configured to mate with the first coupling structure 112a. The second coupling structure 145 is complementary to the first coupling structure 112a. The second coupling structure 145 may have a pre-defined cross-sectional shape, such as, without limitation, rectangular, square, triangular, etc. In an embodiment, the second coupling structure 145 is a rim having a rectangular cross-section. The cavity 143 has a face 147 configured to mate with the top surface 111a of the tibial base plate 110.
[44] The tibial base plate 110 and the tibial liner 140 may be assembled in a similar manner as described earlier with respect to the tibial liner 130. An assembled view of an exemplary implant 200 including tibial base plate 110 and the tibial liner 140 is illustrated in Fig. 4c.
[45] Fig. 5a and Fig. 5b depict a front view and a cross-sectional view, respectively, of an exemplary tibial liner 150. The tibial liner 150 is coupled with the tibial base plate 110. In an embodiment, the tibial liner 150 is a PS tibial liner. The tibial liner 150 and the tibial base plate 110 form a part of a PS knee prosthesis (or implant). The tibial liner 150 may be made of a material including, but not limited to, Ultra-High Molecular Weight Polyethylene (UHMWPE), Polymethyl methacrylate (PMMA), Highly cross-linked polyethylene (HXLPE) including Vitamin E, etc. In an example implementation, the tibial liner 150 is made of Ultra-High Molecular Weight Polyethylene (UHMWPE). The dimensions of the tibial liner 150 may vary according to or based upon the anatomy of the patient and/or of the patient population in consideration.
[46] The tibial liner 150 has a proximal end 150a and a distal end 150b. The tibial liner 150 has a top face 152 situated towards the proximal end 150a. The top face 152 provides an articulating surface for a femoral component (not shown). The tibial liner 150 includes a post 154 protruding from the top face 152. In an embodiment, the post 154 is provided centrally on the top face 152. The post 154 replaces damaged Posterior Cruciate Ligament (PCL). The post 154 interacts with a femoral cam (not shown) to prevent anterior translation of the femur on the tibia, while allowing femoral rollback during flexion.
[47] In an embodiment, the tibial liner 150 has a bottom face 151 situated towards the distal end 150b. The bottom face 151 mates with a surface of the tibia. In an embodiment, the tibial liner 150 includes a cavity 153 provided on the bottom face 151. The shape of the cavity 153 matches with the shape of the tibial base plate 110. In an embodiment, the cavity 153 includes a second coupling structure 155 provided at least partially along a periphery of the cavity 153. In an embodiment, the second coupling structure 155 extends along the entire periphery of the cavity 153. The second coupling structure 155 is configured to mate with the first coupling structure 112a. The second coupling structure 155 is complementary to the first coupling structure 112a. The second coupling structure 155 may have a pre-defined cross-sectional shape, such as, without limitation, rectangular, triangular, square, dovetail, etc. In an embodiment, the second coupling structure 155 is a rim having rectangular cross-section. The cavity 153 has a face 157 configured to mate with the top surface 111a of the tibial base plate 110. The tibial base plate 110 and the tibial liner 150 may be assembled in a similar manner as described earlier with respect to the tibial liner 130.
[48] Fig. 6a and Fig. 6b depict a front view and a cross-sectional view, respectively, of an exemplary tibial liner 160. The tibial liner 160 is coupled with the tibial base plate 110. In an embodiment, the tibial liner 160 is a hinge tibial liner and may be used in revision surgeries, salvage surgeries, and/or in complex primary knee replacement surgeries involving severe deformity or tumors. The tibial liner 160 and the tibial base plate 110 form a part of a hinged knee prosthesis (or implant). The tibial liner 160 may be made of a material including, but not limited to, Ultra-High Molecular Weight Polyethylene (UHMWPE), Polymethyl methacrylate (PMMA), Highly cross-linked polyethylene (HXLPE) including Vitamin E, etc. In an example implementation, the tibial liner 160 is made of Ultra-High Molecular Weight Polyethylene (UHMWPE). The dimensions of the tibial liner 160 may vary according to or based upon the anatomy of the patient and/or of the patient population in consideration.
[49] The tibial liner 160 has a proximal end 160a and a distal end 160b. The tibial liner 160 has a top face 162 situated towards the proximal end 150a. The top face 162 provides an articulating surface for a femoral component (not shown). The tibial liner 160 includes a hole 164 on the top face 152. In an embodiment, the hole 164 is a through-hole and is provided centrally on the top face 152. The hole 164 is configured to accommodate T-joint femoral component (not shown). The T-joint may be assembled with a pivot pin, which acts as a hinge mechanism in the hinged knee prosthesis.
[50] In an embodiment, the tibial liner 160 has a bottom face 161 situated towards the distal end 160b. The bottom face 161 mates with a surface of the tibia. In an embodiment, the tibial liner 160 includes a cavity 163 provided on the bottom face 161. The shape of the cavity 163 matches with the shape of the tibial base plate 110. In an embodiment, the cavity 163 includes a second coupling structure 165 provided at least partially along a periphery of the cavity 163. In an embodiment, the second coupling structure 165 extends along the entire periphery of the cavity 163. The second coupling structure 165 is configured to mate with the first coupling structure 112a. The second coupling structure 165 is complementary to the first coupling structure 112a. The second coupling structure 165 may have a pre-defined cross-sectional shape, such as, without limitation, rectangular, triangular, square, dovetail, etc. In an embodiment, the second coupling structure 165 is a rim having a rectangular cross-section. The cavity 163 has a face 167 configured to mate with the top surface 111a of the tibial base plate 110. The tibial base plate 110 and the tibial liner 160 may be assembled in a similar manner as described earlier with respect to the tibial liner 130.
[51] Though the present disclosure has been explained using the first coupling structure 112a being a slot and the second coupling structures 135, 145, 155 and 165 being a rim, according to another embodiment, the first coupling structure 112a may be a rim and the second coupling structures may be a slot. Further, it should be appreciated that the first coupling structure 112a and the second coupling structures 135, 145, 155 and 165 include any complementary coupling structures capable of locking with each other and the same is within the scope of the present disclosure.
[52] According to an embodiment, the tibial base plate 110 may be coupled with a tumor cone that may be implanted in the tibia of a patient with a bone tumor during a tumor surgery. During such a surgery, a part of the tibia is removed and tumor cone is implanted at that location. The tumor cone provides support and stability to the patient’s knee joint. Fig. 7a and Fig. 7b depict a perspective view and a top view, respectively, of an exemplary tumor cone 170. The tumor cone 170 is coupled to the tibial base plate 110. The tumor cone 170 may be made of a material including, but not limited to, titanium, cobalt chromium, Stainless Steel 316 (SS316), etc. In an exemplary embodiment, the tumor cone 170 is made of a titanium alloy. The dimensions of the tumor cone 170 may vary according to or based upon the anatomy of the patient and/or of the patient population in consideration.
[53] The tumor cone 170 extends has a proximal end 170a and a distal end 170b. In an embodiment, the tumor cone 170 has a generically conical structure such that the tumor cone 170 has a tapered profile from the proximal end 170a towards the distal end 170b. The tumor cone 170 has a top surface 171 situated at the proximal end 170a. The top surface 171 is configured to mate with the bottom surface 111b of the tibial base plate 110. The tumor cone 170 includes a wall 173 provided circumferentially along the top surface 171. An inner surface 173a of the wall 173 is configured to mate with a face 112b (depicted in Fig. 1b) of the peripheral surface 112 of the tibial base plate 110. The face 112b is disposed distal to (i.e., below) the first coupling structure 112a. This allows the tibial base plate 110 to be coupled with a desired tibial liner (for example, any of the tibial liners described herein) via the first coupling structure 112a as explained earlier while assembling the tibial base plate 110 with the tumor cone 170.
[54] In an embodiment, the tumor cone 170 includes a slot 175 configured to receive the keel 117. The slot 175 is provided on the top surface 171 of the tumor cone 170. The slot 175 is situated so as to align with the position of the keel 117 on the tibial base plate 110. In the depicted embodiment, the slot 175 is provided centrally on the top surface 171. Further, the shape and dimensions of the slot 175 correspond to the shape and dimensions of the keel 117. In the depicted embodiment, the slot 175 has a body and two arms configured to receive the body and the two wings of the keel 117, respectively. A bottom face 175a of the slot 175 has a hole 177. The hole 177 extends towards the distal end 170b for a pre-defined length. Internal threads (not shown) are provided in the hole 177 towards the proximal end 170a. The internal threads extend for at least a partial length of the hole 177. In an example implementation, the internal threads extend for the entire length of the hole 177.
[55] In an embodiment, the tibial base plate 110 and the tumor cone 170 are coupled to each other using a fastener. Fig. 8 depicts an exemplary fastener 180. In an embodiment, the fastener 180 is a screw. The fastener 180 has a proximal end 180a and a distal end 180b. In an embodiment, the fastener 180 includes a head 181 and a body 183. The head 181 is situated towards the proximal end 180a. The proximal portion of hole 119 of the tibial base plate 110 is configured to receive the head 181. The shape of the proximal portion of the hole of the tibial base plate 110 and the head 181 match with each other. The head 181 may have a shape such as, without limitation, cylindrical, conical, frustum, hexagonal, etc. In an embodiment, the head 181 has a frustum shape. The body 183 extends from the head 181 towards the distal end 180b. The body 183 is generally cylindrical. Threads 185 are provided on at least a portion of the body 183 towards the distal end 180b. In an embodiment, the threads 185 extend for a partial length of the body 183. The threads 185 are configured to engage with the internal threads of the tumor cone 170 and are complementary to the internal threads of the tumor cone 170.
[56] To assemble the tibial base plate 110 and the tumor cone 170 with each other, the tibial base plate 110 is disposed over the tumor cone 170 such that the keel 117 and the slot 175 are aligned with each other. The keel 117 is inserted into the slot 175 until the keel 117 is fully disposed within the slot 175 and the face 112b of the peripheral surface 112 of the tibial base plate 110 mates with the inner surface 173a of the tumor cone 170. Further, the top surface 171 of the tumor cone 170 mates with the bottom surface 111b of the tibial base plate 110. The fastener 180 is inserted through the hole 119 of the tibial base plate 110 such that the head 181 sits within the proximal portion of the hole 119 of the tibial base plate 110 and a face 181a of the head 181 mates with the inner surface 113 of the hole 119 of the tibial base plate 110. Further, the body 183 extends through the hole of the tibial base plate 110 and the aperture 115 of the keel 117, and the threads 185 are disposed within the hole 177. The fastener 180 is rotated, for example, using a screwdriver, such that the threads 185 engage with the internal threads of the tumor cone 170, thereby coupling the tibial base plate 110 and the tumor cone 170 with each other.
[57] The present disclosure provides several advantages. A proposed tibial base plate is capable of being coupled to tibial liners of different types and sizes. This decreases the inventory of components required during a surgery since only a single tibial base plate may be needed. Further, since one size of the proposed tibial base plate can be used for all sizes and types of a tibial liner, the size matrix is also reduced. Consequently, overall medical cost for the surgery is reduced. Further, teachings of the present disclosure allow a surgeon to use different types and sizes of a tibial liner without changing the tibial base plate to ascertain an optimal fit according to the patient’s anatomy and requirements. As a result, overall procedural time and complexity are reduced. This leads to enhancing patient outcome.
[58] 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. An implant (100, 200) comprising:
a. a tibial base plate (110) comprising:
i. a top surface (111a);
ii. a bottom surface (111b);
iii. a peripheral surface (112) extending between the top surface (111a) and the bottom surface (111b) of the tibial base plate (110), the peripheral surface (112) comprising a first coupling structure (112a) extending for at least a partial length of the peripheral surface (112) of the tibial base plate (110); and
b. a tibial liner (130, 140, 150, 160) comprising:
i. a bottom face (131, 141, 151, 161); and
ii. a cavity (133, 143, 153, 163) provided on the bottom face (131, 141, 151, 161) of the tibial liner (130, 140, 150, 160), the cavity (133, 143, 153, 163) comprising a second coupling structure (135, 145, 155, 165) extending for at least a partial length of a periphery of the cavity (133, 143, 153, 163), the second coupling structure (135, 145, 155, 165) is complementary to the first coupling structure (112a) and is configured to mate with the first coupling structure (112a), thereby coupling the tibial liner (130, 140, 150, 160) with the tibial base plate (110).
2. The implant (100, 200) as claimed in claim 1, wherein the first coupling structure (112a) comprises a slot and the second coupling structure (135, 145, 155, 165) comprises a rim.
3. The implant (100, 200) as claimed in claim 1, wherein the first coupling structure (112a) comprises a rim and the second coupling structure (135, 145, 155, 165) comprises a slot.
4. The implant (100, 200) as claimed in claim 1, wherein the tibial liner (130, 140, 150, 160) comprises a cruciate retaining tibial liner (130, 140), a posterior stabilized tibial liner (150), a hinge tibial liner (160).
5. The implant (100, 200) as claimed in claim 1, wherein the tibial liner (130, 140, 150, 160) comprises the bottom face (131, 141, 151, 161) is configured to mate with a surface of the tibia.
6. The implant (100, 200) as claimed in claim 1, wherein a face (137, 147, 157, 167) of the cavity (133, 143, 153, 163) of the tibial liner (130, 140, 150, 160) is configured to mate with the top surface (111a) of the tibial base plate (110).
7. The implant (100, 200) as claimed in claim 1, wherein the implant (100, 200) comprises a keel (117) extending from the bottom surface (111b) of the tibial base plate (110), the keel (117) comprising an aperture (115) extending from a distal end (110b) of the keel (117) towards a proximal end (110a) of the keel (117), the aperture (115) defining an inner surface (117b).
8. The implant (100, 200) as claimed in claim 7, wherein the implant (100, 200) comprises a plug (120) configured to close the aperture (115) of the keel (117), the plug (120) comprising a first face (121) configured to be in flush with a distal face (117a) of the keel (117) and a second face (123) configured to mate with the inner surface (117b) of the keel (117).
9. The implant (100, 200) as claimed in claim 7, wherein the implant (100, 200) comprises a tumor cone (170) coupled to the tibial base plate (110), the tumor cone (170) comprising:
a. a top surface (171) configured to mate with the bottom surface (111b) of the tibial base plate (110);
b. a wall (173) provided circumferentially along the top surface (171) and having an inner surface (173a) configured to mate with a face (112b) of the peripheral surface (112) of the tibial base plate (110); and
c. a slot (175) configured to receive the keel (117).
10. The implant (100, 200) as claimed in claim 9, wherein a hole (177) is provided on a bottom face (175a) of the slot (175), the hole (177) having internal threads, wherein the implant (100, 200) comprises a fastener (180) comprising:
a. a head (181) configured to reside in a proximal portion of a hole (119) provided on the top surface (111a) of the tibial base plate (110); and
b. a body (183) having threads (185) provided on at least a portion of the body (183) towards a distal end (180b) of the fastener (180), the threads (185) are configured to engage with the internal threads of the hole (177) of the tumor cone (170).