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:
HINGE KNEE JOINT PROSTHESIS

2. APPLICANT:
Meril Healthcare Pvt. Ltd., an Indian company of the Survey No. 135/139, Bilakhia House, Muktanand Marg, Chala, Vapi- 396191, Gujarat, India.

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

FIELD OF THE DISCLOSURE
[001] The present disclosure relates to a knee joint prosthesis. More specifically, the present disclosure relates to a hinge knee joint prosthesis and a method of assembling the same.
BACKGROUND OF THE DISCLOSURE
[002] A knee includes a distal femur, proximal tibia, and patella. The knee joint is a synovial and a complex joint that connects the distal femur, proximal tibia and patella via two articulations namely the tibiofemoral joint and patellofemoral joint. The distal femur and proximal tibia comprise a tibiofemoral joint, while the distal femur and patella comprise a patellofemoral joint. Additionally, soft tissue such as ligaments and tendons, help stabilize these joints throughout flexion of the knee. However, as time progresses, the knee may become worn out, damaged or diseased. For example, Osteoarthritis decimates articular cartilage within the tibiofemoral and/or patellofemoral joints producing painful bone-on-bone articulation and knee misalignment.
[003] Aforementioned situations require surgical interventions, that involve resecting portions of the distal femur, proximal tibia, and patella and replacing the resected bone with one or more prostheses. The surgical procedure conducted to replace the patellofemoral and tibiofemoral joints is commonly referred to as total knee arthroplasty (“TKA”) or total knee replacement.
[004] Hinge knee joint prostheses is required for patients suffering from substantial stabilizing soft tissue deficiencies, particularly significant laxity or complete removal of the collateral ligaments. Conventional hinge knee joint prostheses offer a one-degree-of-freedom hinge about which the knee flexes and extends. Although, they provide the much-needed knee stability, this is accompanied with restricted normal knee kinematics and pain that hampers the quality of life in patients.
[005] Hence, there arises a need to develop hinge knee joint prosthesis that provide additional degrees of freedom to help mimic certain aspects of natural knee kinematics.
SUMMARY OF THE DISCLOSURE
[006] The present disclosure relates to a hinge knee joint prosthesis. The hinge knee joint prosthesis includes a femoral component including two condyles and a hinge box disposed between the two condyles, a tibial component and a coupling component operatively coupled to the tibial component and the femoral component. The coupling component including a box cover operatively coupled to the hinge box of the femoral component. The box cover includes a connecting member extending between a sixth face and a seventh face of the box cover. The coupling component further includes a t-joint operatively coupled to the box cover, a pivot pin operatively coupled to the t-joint and the box cover, an axial bush operatively coupled with the pivot pin and the t-joint, and an axial locking screw configured to secure the axial bush, the pivot pin and the t-joint with each other. The connecting member is configured to prevent a contact between the femoral component and the t-joint.
[007] The foregoing features and other features as well as the advantages of the disclosure will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
[008] 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 instrumentalities disclosed herein. Moreover, those in the art will understand that the drawings are not to scale.
[009] Fig. 1 depicts an assembled view of a hinge knee joint prosthesis 100, in accordance with one or more exemplary embodiments of the present disclosure.
[0010] Fig. 2A depicts an exploded view 200a of various components of the hinge knee joint prosthesis 100, in accordance with one or more exemplary embodiments of the present disclosure.
[0011] Fig. 2B depicts an exploded view 200b of a coupling component 150 in the hinge knee joint prosthesis, in accordance with one or more exemplary embodiments of the present disclosure.
[0012] Fig. 3 depicts an exploded view 300 of a tibial component of the hinge knee joint prosthesis, in accordance with one or more exemplary embodiments of the present disclosure.
[0013] Fig. 4 is a flowchart illustrating a method 400 for assembling the hinge knee joint prosthesis, in accordance with one or more exemplary embodiments of the present disclosure.
DETAILED DESCRIPTION OF THE DISCLOSURE
[0014] Prior to describing the disclosure 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.
[0015] 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.
[0016] 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.
[0017] 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.
[0018] Referenced throughout this specification, the term hinge knee joint prosthesis system or the hinge knee joint prosthesis is used interchangeably and refer to the system used to stabilize the knee during total knee arthroplasty (“TKA”) or total knee replacement.
[0019] Although the present disclosure is described with examples of a hinge knee joint prosthesis, the teachings of the present disclosure are equally applicable to other osteo-implants and the same is within the scope of the teachings of the present disclosure.
[0020] The hinge knee joint prosthesis facilitates improved flexibility with respect to natural knee kinematics by providing greater degrees of freedom when compared with conventional hinge knee joint prostheses. Further, the hinge knee joint prosthesis as disclosed herein facilitates flexion and hyper extension as well as internal and external rotation. In an embodiment, the hinge knee joint prosthesis includes a box cover having two faces coupled by a connecting member. Such a box cover accords technical advantages such as easier assembly and the longevity of the hinge knee joint prosthesis by reducing the wear and tear. The connecting member may be made of a non-metallic material and prevents metal-to-metal contact between a femoral component and a t-joint in the hinge knee joint prosthesis. This prevention of metal-to-metal contact between the femoral component and the t-joint in the hinge knee joint prosthesis in turn reduces the wear and tear to increase the life-span of the said prosthesis.
[0021] Now referring to the figures, Fig. 1 illustrates an exemplary embodiment of a hinge knee joint prosthesis 100. The hinge knee joint prosthesis 100 includes a femoral component 101, a tibial component 108, a tibial liner 109 and a coupling component 150. The coupling component 150 includes a box cover 102, a t-joint 103, a pivot pin 104, an axial bush 105, an axial locking screw 106 and a box cap 107. When the hinge knee prosthesis 100 is implanted, the femoral component 101 is anchored to a femoral bone of a patient and the tibial component 108 is anchored to a tibia bone of the patient. The coupling component 150 and the tibial component 108 form a flexion bearing around a first axis. The coupling component 150 and the femoral component 101 form a rotary bearing around a second axis oriented transversely to the first axis. In an embodiment, the first axis is the longitudinal axis of the pivot pin 104 and the second axis is the longitudinal axis of the axial bush 105.
[0022] Various embodiments of how different components of the hinge knee joint prosthesis 100 are coupled is explained in conjunction with Figs. 2A, 2B and 3. Fig. 2A is an exploded view 200a of the femoral component 101, the box cover 102 and the box cap 107, in accordance with one or more exemplary embodiments of the present disclosure. The femoral component 101 includes two condyles 101c and 101c’, a first face 210, a second face 213, a third face 239, a fourth face 245, a fifth face 215, a groove 216 and a hinge box 237. In an embodiment, the hinge box 237 is disposed between the two condyles 101c and 101c’. In an embodiment, the hinge box 237 disposed between the two condyles 101c and 101c’ forms an integral component. The box cover 102 includes a first face 211, a third face 238, a fourth face 244, a sixth face 240 (shown in Fig. 2B), a seventh face 241, a first groove 235 and a blind groove 236. The box cover 102 further includes a connecting member 201 extending between the sixth face 240 and the seventh face 241 of the box cover 102. The connecting member 201 includes a second face 212 and a fifth face 218. The box cap 107 includes a first face 214, a second face 234 (shown in Fig. 2B), and a peg 217. In an embodiment, the box cover 102 is formed as an integral component.
[0023] The two condyles 101c and 101c’ are supported by a tibial liner 109. In an embodiment, the femoral component 101 is coupled with the box cover 102 at the hinge box 237 of the femoral component 101 as follows. The hinge box 237 is disposed between the two condyles 101c and 101c’. The first face 210 of the femoral component 101 mates and is concentric with the first face 211 of the box cover 102. The second face 213 of the femoral component 101 mates with the second face 212 of the connecting member 201. Similarly, the third face 239 of the femoral component 101 mates with the third face 238 of the box cover 102. Likewise, the fourth face 245 of the femoral component 101 mates with a fourth face 244 of the box cover 102.
[0024] In an embodiment, the connecting member 201 may be made of a non-metallic material to prevent metal-to-metal contact between the femoral component 101 and the t-joint 103. In an embodiment, the connecting member 201 may be made of a polymeric material such as, without limitation, an ultra-high molecular weight polyethylene (UHMWPE), polyetheretherketone (PEEK), a polymethyl methacrylate (PMMA) or a highly crosslinked polyethylene (HXLPE) including Vitamin E etc. or any suitable medical grade biocompatible polymer material. The connecting member 201 is configured to avoid contact of the second face 213 of the femoral component 101 and a first face 219 on a back side of the t-joint 103.
[0025] For assembly of the femoral component 101 and the box cap 107, the fifth face 215 of the femoral component 101 mates and is concentric with the first face 214 of the box cap 107 and the peg 217 on the box cap 107 engages with the groove 216 of the femoral component 101. The box cap 107 may facilitate closure of an open area at one side of the hinge box 237 of the femoral component 101, while another open area of the hinge box 237 of the femoral component 101 is closed by the box cover 102. This helps to restrict the flow of bone cement into the hinge box 237.
[0026] In an embodiment, the femoral component 101 may be made of any medical grade metallic biocompatible material, such as, without limitation, cobalt-chrome or cobalt-chromium (Cocr), Titanium, chromium-nickel based steels such as stainless steel 316 (SS316) or high nitrogen stainless steels (HNSS) etc. In an embodiment, the box cover 102 and the box cap 107 may be made of non-metallic medical grade biocompatible material such as, without limitation, an ultra-high molecular weight polyethylene (UHMWPE), a polyetheretherketone (PEEK), a polymethyl methacrylate (PMMA) or a highly crosslinked polyethylene (HXLPE) including Vitamin E etc., or any suitable medical grade biocompatible polymer material.
[0027] Fig. 2B is an exploded view 200b of the coupling component 150 including the box cover 102, the t-joint 103, the pivot pin 104, the axial bush 105, the axial locking screw 106 and the box cap 107, in accordance with one or more exemplary embodiments of the present disclosure. The t-joint 103 includes a first face 219, a second face 253, a third face 127, a fourth face 129, a top groove 220, a bottom groove 230 and a hole 233. The pivot pin 104 includes a blind groove 222, a hole 232 and a face 221. The axial bush 105 includes a hole 231, a first face 142, a second face 224 and third face 223. The t-joint 103 is placed between the sixth face 240 and the seventh face 241 of the box cover 102 such that the fifth face 218 of the connecting member 201 mates with the first face 219 on the back side of the t-joint 103. The pivot pin 104 passes through the first groove 235 of the box cover 102, the top groove 220 of the t-joint 103, and sits on the blind groove 236 of the box cover 102. In an embodiment, the pivot pin 104 and the blind groove 236 of the box cover 102 are designed such that the pivot pin 104 sits perfectly on the blind groove 236. The top groove 220 of the t-joint 103 mates and is concentric with the face 221 of the pivot pin 104. The axial bush 105 passes through the bottom groove 230 of the t-joint 103 and mates with the blind groove 222 of the pivot pin 104. The third face 223 of the axial bush 105 mates and is concentric with the blind groove 222 of the pivot pin 104. The second face 224 on a peg 252 of the axial bush 105 mates with the second face 253 on a slot of the t-joint 103. The axial locking screw 106 passes through the hole 231 of the axial bush 105, the hole 232 of the pivot pin 104 and the hole 233 of the t-joint 103. External threads on the face 225 of the axial locking screw 106 interlock with internal threads on the hole 233 of the t-joint 103 so as to securely lock the axial bush 105, the pivot pin 104 and the t-joint 103 with each other. After the pivot pin 104 is secured properly in place, an open hole of a first groove 235 of the box cover 102 is enclosed with the help of the box cap 107. The second face 234 of the box cap 107 mates and is concentric with the face 221 of the pivot pin 104.
[0028] In an embodiment, the t-joint 103, the pivot pin 104 and the axial locking screw 106 may be made of any medical grade metallic biocompatible material, such as, without limitation, cobalt-chrome or cobalt-chromium (Cocr), Titanium, chromium-nickel based steels such as stainless steel 316 (SS316) or high nitrogen stainless steels (HNSS) etc. In an embodiment, the axial bush 105 may be made of non-metallic medical grade biocompatible material such as, without limitation, an ultra-high molecular weight polyethylene (UHMWPE), polyetheretherketone (PEEK), a polymethyl methacrylate (PMMA) or a highly crosslinked polyethylene (HXLPE) including Vitamin E etc., or any suitable medical grade biocompatible polymer material.
[0029] Fig. 3 represents an exploded view 300 of the tibial component 108 and a tibial liner 109 in the hinge knee joint prosthesis 100, in accordance with one or more exemplary embodiments of the present disclosure. The hinge knee joint prosthesis 100 includes the tibial liner 109 and a liner securing screw 346. The tibial component 108 includes a post 352, a first face 143, a top surface 351, a groove 349. The tibial liner 109 includes a first face 126, a second face 128, a bottom surface 350, a groove 348. The liner securing screw 346 includes a face 347. The first face 126 of the tibial liner 109 mates with the third face 127 of the t-joint 103 or the second face 128 of the tibial liner 109 mates with the fourth face 129 of the t-joint 103 (as shown in Fig. 1) to restrict the internal external rotation of the hinge knee joint prosthesis 100. The first face 142 of the axial bush 105 mates with the first face 143 of the tibial component 108 (as shown in Fig. 1) to avoid metal to metal contact of the t-joint 103 and the tibial component 108 during the occurrence of extreme wear of the tibial liner 109. The bottom surface 350 of the tibial liner 109 mates with the top surface 351 of the tibial component 108. The liner securing screw 346 is used to fasten the tibial component 108 and the tibial liner 109. The liner securing screw 346 passes through the groove 348 on the tibial liner 109 and the groove 349 on the tibial component 108. The face 347 of the liner securing screw 346 may have external threads and the groove 349 of the tibial component 108 may have internal threads that interlock with each other and secure the tibial component 108 and the tibial liner 109. The post 352 is extruded vertically from the tibial component 108 and gets assembled with the axial bush 105 (as shown in Fig. 1).
[0030] In an embodiment, all components of the hinge knee joint prosthesis 100 may be designed with suitable dimensions and assembled in a manner as described herein.
[0031] In an embodiment, the tibial component 108 and the liner securing screw 346 may be made of any medical grade metallic biocompatible material, such as, without limitation, cobalt-chrome or cobalt-chromium (Cocr), Titanium, chromium-nickel based steels such as stainless steel 316 (SS316) or high nitrogen stainless steels (HNSS) etc. In an embodiment, the tibial liner 109 may be made of non-metallic medical grade biocompatible material such as, without limitation, an ultra-high molecular weight polyethylene (UHMWPE), polyetheretherketone (PEEK), a polymethyl methacrylate (PMMA) or a highly crosslinked polyethylene (HXLPE) including Vitamin E etc., or any suitable medical grade biocompatible polymer material.
[0032] In an embodiment, the femoral component 101 and the coupling component 150 may be designed with suitable dimensions and assembled in a manner to facilitate internal external rotation functionality around the longitudinal axis of the axial bush 105.
[0033] Fig. 4 is a flowchart illustrating a method 400 for assembling the hinge knee joint prosthesis 100, in accordance with one or more exemplary embodiments of the present disclosure. The method 400 starts with step 401. At step 401, a femoral component (such as the femoral component 101) is coupled to a box cover (such as the box cover 102). The femoral component 101 is coupled to the box cover 102 as described in Fig. 2A. At step 403, a t-joint (such as the t-joint 103) is coupled with the box cover (such as the box cover 102). The coupling of the t-joint 103 with the box cover 102 is described in Fig. 2B. At step 405, a pivot pin (such as the pivot pin 104) is coupled with a t-joint (such as the t-joint 103) and the box cover (such as the box cover 102). The coupling of the pivot pin 104 with the t-joint 103 and the box cover 102 is described in Fig. 2B. At step 407, an axial bush (such as the axial bush 105) is coupled with the pivot pin 104 and the t-joint 103. The coupling of the axial bush 105 with the pivot pin 104 and the t-joint 103 is explained in Fig. 2B. At step 409, a box cap (such as the box cap 107) is coupled with the pivot pin 104 and femoral component 101 as explained in Fig. 2A and 2B. At step 411, a tibial component (such as the tibial component 108) is coupled with a tibial liner (such as the tibial liner 109). The coupling of the tibial component 108 and the tibial liner 109 is explained in Fig. 3. At step 413, the tibial component 108 and the tibial liner 109 are coupled with a coupling component (such as the coupling component 150) through the axial bush (such as the axial bush 105). The coupling of the tibial component 108 and the tibial liner 109 with the coupling component 150 is explained in Fig. 1.
[0034] 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 disclosure is/are used. , Claims:WE CLAIM:
1. A hinge knee joint prosthesis (100) comprising:
a femoral component (101) comprising two condyles (101c) and (101c’) and a hinge box (237) disposed between the two condyles (101c) and (101c’);
a tibial component (108); and
a coupling component (150), operatively coupled to the tibial component (108) and the femoral component (101), the coupling component (150) comprising:
a box cover (102) operatively coupled to the hinge box (237) of the femoral component (101), the box cover (102) comprising a connecting member (201) extending between a sixth face (240) and a seventh face (241) of the box cover (102);
a t-joint (103) operatively coupled to the box cover (102);
a pivot pin (104) operatively coupled to the t-joint (103) and the box cover (102);
an axial bush (105) operatively coupled with the pivot pin (104) and the t-joint (103); and
an axial locking screw (106) configured to secure the axial bush (105), the pivot pin (104) and the t-joint (103) with each other;
wherein the connecting member (201) is configured to prevent a contact between the femoral component (101) and the t-joint (103).
2. The hinge knee joint prosthesis (100) as claimed in claim 1, wherein a first face (210) of the femoral component (101) mates with a first face (211) of the box cover (102),
a second face (213) of the femoral component (101) mates with a second face (212) of the connecting member (201), a third face (239) of the femoral component (101) mates with a third face (238) of the box cover (102), and a fourth face (245) of the femoral component (101) mates with a fourth face (244) of the box cover (102).
3. The hinge knee joint prosthesis (100) as claimed in claim 1, wherein the hinge knee joint prosthesis (100) comprises a box cap (107), wherein a fifth face (215) of the femoral component (101) mates with a first face (214) of the box cap (107), a peg (217) on the box cap (107) engages with a groove (216) of the femoral component (101), and a second face (234) of the box cap (107) mates and is concentric with a face (221) of the pivot pin (104).
4. The hinge knee joint prosthesis (100) as claimed in claim 1, wherein:
the t-joint (103) is disposed between the sixth face (240) and the seventh face (241) of the box cover (102) in a manner that a fifth face (218) of the connecting member (201) mates with the first face (219) of the t-joint (103);
the pivot pin (104) passes through a first groove (235) of the box cover (102), a top groove (220) of the t-joint (103), and sits on a blind groove (236) of the box cover (102);
the axial bush (105) passes through a bottom groove (230) of the t-joint (103) and mates with a blind groove (222) of the pivot pin (104), a third face (223) of the axial bush (105) mates with the blind groove (222) of the pivot pin (104), and a second face (224) on a peg (252) of the axial bush (105) mates with a second face (253) on a slot of the t-joint (103); and
the axial locking screw (106) passes through a hole (231) of the axial bush (105), a hole (232) of the pivot pin (104) and a hole (233) of the t-joint (103) and external threads on a face (225) of the axial locking screw (106) interlock with internal threads on the hole (233) of the t-joint (103), thereby securing the axial bush (105), the pivot pin (104) and the t-joint (103) with each other.
5. The hinge knee joined prosthesis (100) as claimed in claim 1, wherein the hinge knee joint prosthesis (100) comprises a tibial liner (109), disposed over the tibial component (108), comprising a first face (126) and a second face (128) configured to mate with a third face (127), and a fourth face (129), respectively, of the t-joint (103), wherein the two condyles (101c) and (101c’) are supported by the tibial liner (109).
6. The hinge knee joint prosthesis (100) as claimed in claim 5, wherein the hinge knee joint prosthesis (100) comprises a liner securing screw (346), wherein:
a bottom surface (350) of the tibial liner (109) mates with a top surface (351) of the tibial component (108);
the liner securing screw (346) passes through a groove (348) on the tibial liner (109) and a groove (349) on the tibial component (108); and
a face (347) of the liner securing screw (346) having external threads interlocks with the groove (349) of the tibial component (108) having internal threads to secure the tibial component (108) and the tibial liner (109).
7. The hinge knee joint prosthesis (100) as claimed in claim 1, wherein a post (352) vertically extruded from the tibial component (108) is assembled with the axial bush (105).
8. The hinge knee joint prosthesis (100) as claimed in claim 1, wherein a first face (142) of the axial bush (105) mates with a first face (143) of the tibial component (108) to prevent a contact of the t-joint (103) and the tibial component (108).
9. The hinge knee joint prosthesis (100) as claimed in claim 1, wherein the coupling component (150) and the tibial component (108) form a flexion bearing around a first axis and wherein the coupling component (150) and the femoral component (101) form a rotary bearing around a second axis oriented transversely to the first axis.
10. The hinge knee joint prosthesis (100) as claimed in claim 1, wherein the box cover (102) with the connecting member (201) is an integrally formed component.
11. The hinge knee joint prosthesis (100) as claimed in claim 1, wherein the connecting member (201) is made of a polymeric material.
12. The hinge knee joint prosthesis (100) as claimed in claim 1, wherein the box cover (102) is made of a polymeric material.
13. The hinge knee joint prosthesis (100) as claimed in claim 1, wherein the connecting member (201) is configured to prevent a second face (213) of the femoral component (101) contacting a first face (219) of the t-joint (103) in the hinge knee joint prosthesis (100).