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:
CENTRALIZER

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 INVENTION
[1] The present disclosure relates to a bio-medical implant. More particularly, the present disclosure relates to a centralizer.
BACKGROUND OF INVENTION
[2] Human body consists of various joints which provides the framework for movement and locomotion to the human body. Sometimes, various traumatic incidents such as sporting injuries, falls, vehicle accidents etc. and conditions like arthritis and osteoporosis may lead to bone breakage and fractures of bones. These fractures are sometimes treatable but, in some conditions, there is need to replace joints.
[3] Joint replacement is a surgical procedure in which parts of an arthritic or damages or fractured joints are removed and replaced with a prosthesis (or implants). These prostheses are specially designed to replicate the movement of normal, healthy joints.
[4] There are conditions when the implants may become loose. During conditions like osteoporosis, there is lack of osteogenic load on the bones caused by low bone mass which makes them more prone to fractures. This leads to lack of bone ingrowth between the implant and the bone. which results in improper distribution of osteogenic load on the implant causing them to sink into the bones. In some conditions the prosthesis may also move from its place.
[5] To address this problem, centralizers are used to fix a stem of an implant and then place it in the medullary canal of the bone. The centralizers help in aligning a distal tip of the implant in the medullary canal of the bone.
[6] However, commercially available centralizers’ performance deteriorates due to the stress induced during the insertion of the stem. This leads to incorrect positioning of the stem, leading to periprosthetic fractures after the surgical procedure. Further, it may also cause the centralizer to break during the insertion of the stem.
[7] Thus, there arises a need for a centralizer that overcomes the problems associated with the conventional centralizers.
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 centralizer. In an embodiment, the centralizer includes a base, a plurality of wings, a central portion and a plurality of slots. The plurality of slots is provided on at least one of: the base, at least one wing of the plurality of wings and the central portion.
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. 1 depicts a perspective view of a centralizer 100, according to an embodiment of the present disclosure.
[12] Fig 2. depicts a perspective view of a centralizer 200, according to an embodiment of the present disclosure.
DETAILED DESCRIPTION OF THE DRAWINGS
[13] 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.
[14] 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.
[15] 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.
[16] 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
[17] The present disclosure discloses a centralizer. The proposed centralizer is designed in such a way that the centralizer engages with a distal end of a stem prosthesis to keep a prosthetic implant away from the internal surface of the cavity of bone in which the stem prosthesis is being inserted. The proposed centralizer also avoids sinkage or slippage of the stem prosthesis and reduces the risk of osteoporosis. In an embodiment, the stem prosthesis is an intramedullary cemented stem prosthesis. The stem prosthesis may be any stem prosthesis used in total knee arthroplasty (TKA), total hip arthroplasty (THA) or total shoulder arthroplasty (TSA), etc.
[18] The centralizer includes a plurality of wings. At the time of stem prosthesis insertion, the plurality of wings aligns with the intramedullary canal of the bone. As stem prosthesis is pushed, the centralizer gradually contracts, causing the plurality of wings to flex towards a central axis of the centralizer.
[19] The centralizer includes a base, a plurality of wings, and a central portion. The centralizer is provided with a plurality of slots on at least one of: the base, at least one wing of the plurality of wings and the central portion. In an embodiment, the plurality of slots extends at least partially along a length of at least one of: the base, the at least one wing of the plurality of wings and the central portion. The plurality of slots minimizes the stress on the centralizer induced due to the flexing of the wings. For example, at least one slot of the plurality of slots is provided adjacent to a region where the central portion couples with the plurality of wings (hereinafter referred to as a connecting region) reduces the stress in the connecting region. The plurality of slots also enhances the flexibility of the plurality of wings. This increases overall strength and flexibility of the centralizer, thereby improving the performance of the centralizer during and after the implantation procedure. In addition, the reduction in the stress during the implantation procedure due to the plurality of slots minimizes breakage of the centralizer. Consequently, the longevity of the centralizer increases and overall reliability and safety of the prosthetic implant is enhanced.
[20] Fig. 1 depicts a perspective view of a centralizer 100 according to an embodiment. The centralizer 100 has a proximal end 100a and a distal end 100b. In an embodiment, the centralizer 100 includes a base 102, a plurality of wings 106n (hereinafter referred to as the wings 106n) and a central portion 104. The central portion 104 has a cylindrical shape, in an embodiment. The central portion 104 has an opening 101 at a proximal end of the central portion 104. The opening 101 is configured to receive a distal end of a stem prosthesis (not shown). The dimensions of the opening 101 are designed such that the distal end of the stem prosthesis fits tightly within the opening 101. The distal end 102b of the base 102 may be either open or closed. In an embodiment, the distal end 102b of the base 102 may be curved such that the base 102 resembles a bullet shape. This provides a flexibility for accommodation of different surgical requirements and preferences.
[21] The base 102 has a proximal end 102a and a distal end 102b. The base 102 has a cylindrical shape, according to an embodiment. Each wing 106n of the wings 106n have a proximal end 106n1 and a distal end 106n2. The distal end 106n2 of each wing 106n is coupled to the proximal end 102a of the base 102. In an embodiment, the base 102 and the wings 106n form an integrated structure. The wings 106n project radially outward from the proximal end 102a of the base 102. In an embodiment shown in Fig. 1, the centralizer 100 includes three wings 106n. It should be appreciated though that the centralizer 100 may include less than three or more than three wings 106n. In an embodiment, the wings 106n may be equally spaced around the circumference of the base 102. In an exemplary implementation, the wings 106n are generally rectangular with rounded edges at the proximal end 106n1. The wings 106n may have any other suitable shape, and the same is covered in the scope of the present disclosure. The centralizer 100 can be made up of materials including, but not limited to, polymethylmethacrylate (PMMA), ultra-high molecular weight polyethylene (UHMWPE), highly cross-linked polyethylene (HXLPE), polyetheretherketone (PEEK), or any other suitable medical grade biocompatible material. The distal end of the central portion 104 is coupled to the plurality of wings 106n using, for example, snap-fit, tapered fit, etc. In an embodiment, the central portion 104 and the plurality of wing 106n and the base 102 form an integral structure.
[22] At the time of stem prosthesis insertion, the wings 106n facilitate precise alignment of the stem prosthesis with the intramedullary canal of the bone. The wings 106n also provide optimal support and stability to the stem prosthesis post-insertion and help to hold the stem prosthesis away from the wall of medullary canal during implantation.
[23] According to an embodiment, the centralizer 100 includes a plurality of stoppers 107 (or the stoppers 107). In an exemplary implementation shown in Fig. 1, each wing 106n is provided with one stopper 107 of the stoppers 107. The stoppers 107 are situated on the medial side of the wings 106n. The stoppers 107 are designed to allow the wings 106n to achieve an appropriate degree of flexion while maintaining a balance between joint stability and mobility, and restrict the wings 106n from flexing beyond the appropriate degree of flexion. The appropriate degree of flexion for the wings 106n depends upon the diameter of the intramedullary canal into which the stem prosthesis is being inserted. In an exemplary implementation, the stoppers 107 are wedge-shaped. It should be appreciated though the stoppers 107 may have any other suitable shape, such as, bead, pear, rib, block, profile embossed, etc. without deviating from the scope of the present disclosure. The stoppers 107 may be positioned vertically or horizontally with respect to the length of the wings 106n.
[24] The centralizer 100 includes a plurality of slots 108 (hereinafter referred to as slots 108). In an embodiment, the slots 108 are disposed from the distal end 102b of the base 102 and extend at least partially along the length of the wings 106n from the distal end 106n2 of the wings 106n as well as extend at least partially along the length of the central portion 104 from a distal end of the central portion 104. The slots 108 may extend at least partially through the width of the base 102, the wings 106n and the central portion 104. In the depicted embodiment, the slots 108 extend through the entire width of the base 102, the wings 106n and the central portion 104 so that they form holes (as shown in Fig. 1). In an exemplary implementation as shown in Fig. 1, the slots 108 have a vertical orientation and have a rectangular shape.
[25] Fig 2. depicts a perspective view of a centralizer 200 according to an embodiment. The centralizer 200 has a proximal end 200a and a distal end 200b. In an embodiment, the centralizer 200 includes a base 202, a plurality of wings 206n (hereinafter referred to as the wings 206n) and a central portion 204. The central portion 204 has a cylindrical shape, in an embodiment. The central portion 204 includes a hollow opening 201 at a proximal end of the central portion 204. The opening 201 is configured to receive a distal end of a stem prosthesis (not shown). The dimensions of the opening 201 are designed such that the distal end of the stem prosthesis fits tightly within the opening 201. The distal end 202b of the base 202 may be either open or closed. In an embodiment, the distal end 202b of the base 202 may be curved such that the base 202 resembles a bullet shape. This provides a flexibility for accommodation of different surgical requirements and preferences.
[26] The base 202 has a proximal end 202a and a distal end 202b. The base 202 has a cylindrical shape, according to an embodiment. Each wing 206n of the wings 206n have a proximal end 206n1 and a distal end 206n2. The distal end 206n2 of each wing 206n is coupled to the proximal end 202a of the base 202. In an embodiment, the base 202 and the wings 206n form an integrated structure. The wings 206n project radially outward from a distal end 202b of the base 202. In an embodiment shown in Fig. 2, the centralizer 200 includes three wings 206n. It should be appreciated though that the centralizer 200 may include less than three or more than three wings 206n. In an embodiment, the wings 206n may be equally spaced around the circumference of the base 202. In an exemplary implementation, the wings 206n are generally rectangular with rounded edges at the proximal end 206n1. The wings 206n may have any other suitable shape, and the same is covered in the scope of the present disclosure. The centralizer 200 can be made up of materials including, but not limited to, polymethylmethacrylate (PMMA), UHMWPE, HXLPE, PEEK, or any other suitable medical grade biocompatible material. The distal end of the central portion 204 is coupled to the plurality of wings 206n using, for example, snap-fit, tapered fit, etc. In an embodiment, the central portion 204 and the plurality of wing 206n and the base 202 form an integral structure.
[27] At the time of stem prosthesis insertion, the wings 206n facilitate precise alignment of the stem prosthesis with the intramedullary canal of the bone. The wings 206n also provide optimal support and stability to the stem prosthesis post-insertion and help to hold the stem prosthesis away from the wall of medullary canal during implantation.
[28] The centralizer 200 includes a plurality of slots 208 (hereinafter referred to as slots 208). In an embodiment, the slots 208 include a first plurality of slots 208a (hereinafter referred to as slots 208a) and a second plurality of slots 208b (hereinafter referred to slots 208b). According to an embodiment shown in Fig. 2, the slots 208a are disposed along the length of the base 202. The slots 208a have a first orientation (e.g., a vertical orientation) and have a rectangular shape. In an embodiment, the slots 208b are disposed on the wings 206n and extend partially along the length of the wings 206n from the distal end 206n2 of the wings 206n. The slots 208b have a second orientation different than the first orientation. It should be appreciated that the first and the second orientation depicted in Fig. 2 is merely exemplary, the first and the second orientation may include any suitable orientations, e.g., vertical, horizontal, slanted, etc. In an embodiment, the slots 208b have a horizontal orientation and have a rectangular shape. The slots 208a and 208b may extend at least partially through the width of the base 202, and the wings 206n, respectively. In the depicted embodiment, the slots 208a and 208b extend through the entire width of the base 202 and the wings 206n, respectively, so that they form holes (as shown in Fig. 2).
[29] The slots 108 of the centralizer 100 and the slots 208 of the centralizer 200 are illustrated for exemplary purpose only and it should be appreciated that various embodiments for the slots 108 or the slots 208 are contemplated within the scope of the present disclosure. For example, the slots (108, 208) are provided at least partially on the surface of the centralizer (100, 200). The slots (108, 208) extend at least partially along a length of at least one of: the base (102, 202), at least one wing (106n, 206n) of the wings (106n, 206n), and the central portion (104, 204) from a respective distal end. The slots (108, 208) extend at least partially through a width of at least one of: the base (102, 202), the at least one wing (106n, 206n) and the central portion (104, 204). The slots (108, 208) may extend at least partially along the length of the base (102, 202) from the distal end (102b, 202b) of the base (102, 202). According to an embodiment, the slots (108, 208) may extend at least partially along the length of the wings (106n, 206n) from the distal end (106n2, 206n2) of the wings (106n, 206n). In an embodiment, the slots (108, 208) may extend at least partially along the length of the central portion (104, 204) from the distal end (104b, 204b) of the central portion (104, 204). In an embodiment, at least one slot of the slots (108, 208) is disposed adjacent to a region where the distal end of the central portion (104, 204) couples with the plurality of wings (106n, 206n) (hereinafter, referred to as a connecting region). In an embodiment, at least one slot of the slots (108, 208) may span a portion of the base (102, 202) at the proximal end (102a, 202a) of the base (102, 202) and a portion of the wings (106n, 206n) at the distal end (206n2) of the wings (106n, 206n) – as illustrated in Fig. 1. In an embodiment, at least one slot of the slots (108, 208) may span a portion of the base (102, 202) at the proximal end (102a, 202a) of the base (102, 202) and a portion of the central portion (104, 204) at the distal end of the central portion (104, 204) – as illustrated in Fig. 1. In an embodiment, the slots (108, 208) may be provided on at least one wing of the wings (106n, 206n). The slots (108, 208) may have an orientation such as horizontal, vertical, slanted, etc. In an embodiment, all slots (108, 208) may have the same orientation (horizontal, vertical, slanted, etc.). In another embodiment, the slots (108, 208) may have different orientations. For example, some slots of the slots (108, 208) may be vertical while other slots of the slots (108, 208) may be slanted and so on. In an exemplary implementation shown in Fig. 2, the slots 208 includes the slots 208a having vertical orientation and the slots 208b having horizontal orientation. The slots (108, 208) may have straight or curved edges. The slots (108, 208) may have various shapes including, but not limited to, rectangular, zig-zag, triangular, diamond, fish scale, undulating (for example, snake shaped), etc. In an exemplary implementation shown in Fig. 1 and Fig. 2, the slots (108, 208) are rectangular with straight edges. In an embodiment, the slots (108, 208) may have the same or different shape (for example, some slots of the slots (108, 208) may be rectangular whereas other slots of the slots (108, 208) may be diamond shaped). In an embodiment, the slots (108, 208) may have the same or different edges (for example, some slots of the slots (108, 208) may have straight edges while other slots of the slots (108, 208) may have curved edges).
[30] In an embodiment, at the time of stem prosthesis insertion, the distal end of the stem prosthesis is inserted into the opening (101, 201) and coupled with the centralizer (100, 200) using, e.g., a fix-fit mechanism, a snap-fit mechanism, a taper-fit mechanism, etc. such that the central portion (104, 204) covers a distal portion of the stem prosthesis. The stem prosthesis is then inserted into a reamed intramedullary canal of the bone and cemented in place. During the insertion of the stem prosthesis, the wings (106n, 206n) align with the intramedullary canal of the bone, thereby helping to centralize the stem prosthesis into the intramedullary canal. Thus, the centralizer (100, 200) helps to ensure that the stem prosthesis is properly aligned and centered within the bone. As stem prosthesis is pushed, the centralizer (100, 200) gradually contracts, causing the wings (106n, 206n) to flex towards a central axis of the centralizer (100, 200). Flexing of the wings (106n, 206n) induces stress in the centralizer (100, 200), in particular in the connecting region.
[31] The slots (108, 208) minimize the stress on the centralizer (100, 200) during implantation. For example, the at least one slot of the slots (108, 208) provided in the connecting region reduce the stress in the connecting regions. The slots (108, 208) also enhance the flexibility of the wings (106n, 206n). This increases overall strength and flexibility of the centralizer (100, 200), thereby improving the performance of the centralizer (100, 200) during and after the implantation procedure.
[32] 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 centralizer (100, 200) comprising:
a) a base (102, 202);
b) a plurality of wings (106n, 206n) coupled to the base (102, 202);
c) a central portion (104, 204) coupled to the plurality of wings (106n, 206n); and
d) a plurality of slots (108, 208) provided on at least one of: the base (102, 202), at least one wing (106n, 206n) of the plurality of wings (106n, 206n) and the central portion (104, 204).
2. The centralizer (100, 200) as claimed in claim 1, wherein the plurality of slots (108, 208) extends at least partially along a length of at least one of: the base (102, 202), the at least one wing (106n, 206n) of the plurality of wings (106n, 206n) and the central portion (104, 204) from a respective distal end.
3. The centralizer (100, 200) as claimed in claim 1, wherein the base (102, 202), the plurality of wings (106n, 206n) and the central portion (104, 204) form an integral structure.
4. The centralizer (100) as claimed in claim 1, wherein each wing (106n) of the plurality of wings (106n) is provided with a stopper (107).
5. The centralizer (100, 200) as claimed in claim 1, wherein at least one slot of the plurality of slots (108, 208) spans a portion of the base (102, 202) at a proximal end (102a, 202a) of the base (102, 202) and a portion of the plurality of wings (106n, 206n) at a distal end (106n2, 206n2) of the plurality of wings (106n, 206n).
6. The centralizer (100, 200) as claimed in claim 1, wherein the plurality of slots (108, 208) extends at least partially through a width of the at least one of: the base (102, 202), at least one wing (106n, 206n) of the plurality of wings (106n, 206n) and the central portion (104, 204).
7. The centralizer (100, 200) as claimed in claim 1, wherein at least one slot of the plurality of slots (108, 208) spans a portion of the base (102, 202) at a proximal end (102a, 202a) of the base (102, 202) and a portion of the central portion (104, 204) at a distal end of the central portion (104).
8. The centralizer (100) as claimed in claim 1, wherein the plurality of slots (108) is disposed from a distal end (102b) of the base (102), and extends at least partially along the length of the plurality of wings from a distal end (106n2) of the plurality of wings (106n) and at least partially along the length of the central portion (104) from a distal end of the central portion (104).
9. The centralizer (200) as claimed in claim 1, wherein the plurality of slots (208) comprises a first plurality of slots (208a) disposed along the length of the base (202) and a second plurality of slots (208b) disposed on the plurality of wings (206n) and extending partially along the length of the plurality of wings (206n)
10. The centralizer (200) as claimed in claim 1, wherein the plurality of slots (208b) comprises a first plurality of slots (208a) having a first orientation and a second plurality of slots (208b) having a second orientation different than the first orientation.
11. The centralizer (100, 200) as claimed in claim 1, wherein at least one slot of the plurality of slots (108, 208) is disposed adjacent to a region where a distal end of the central portion (104, 204) couples with the plurality of wings (106n, 206n).