Description:TECHNICAL FIELD
[1] The present disclosure relates to cemented femoral stem associated with centralizer. Moreover, the present disclosure relates to a cemented femoral stem with detachable wings acting as centralizers.
BACKGROUND
[2] Femoral stem implantation is a surgical procedure that involves inserting an implant (such as hip replacement) in a femoral bone cavity of a subject. The implant may function as an artificial joint that needs to be anchored to the femoral bone. For anchoring the implant, i.e., a femoral stem, polymethylmethacrylate (PMMA) bone cement may be used. PMMA is a polymer made from methyl methacrylate monomers. When PMMA bone cement is mixed with an initiator (which may be liquid or powder), the methyl methacrylate monomers may polymerize into a solid substance. Over the past decades, mixing and cementing techniques have evolved to facilitate secure fixation between the femoral bone and the femoral stem. The mixing techniques may, typically, involve usage of a vacuum mixer. The PMMA bone cement may fill a space between the femoral bone and the femoral stem, thereby facilitating a secure fixation of the femoral stem to the femoral bone. Specifically, the PMMA bone cement may form a grout that interlocks the femoral stem with the femoral bone (rather than merely gluing the femoral stem in place). Additionally, the PMMA bone cement helps in distributing stress and load introduced by the insertion of the femoral stem (i.e., the implant) into surrounding bone and reducing wear and tear on the femoral bone.
[3] Currently, a centralizer, which includes at least four wings, is used for centering the femoral stem during application of the PMMA bone cement. The centering of the femoral stem may ensure that the femoral stem is properly positioned within the femoral bone cavity and prevent direct contact between the femoral stem and the femoral bone. This reduces any potential risk of bone damage and loosening of the femoral stem over a long period of time. Additionally, the centralizer ensures that application of the PMMA bone cement around the femoral stem is uniform such that a cement mantle created around the femoral stem is also uniform. The wings of the centralizer may facilitate the uniform application of the PMMA bone cement and, consequently, the creation of the uniform cement mantle. Thus, the centralizer improves the stability of the femoral stem, facilitates formation of a stronger bond between the femoral stem and the femoral bone, and increases longevity of the femoral stem.
[4] Although the centralizer has numerous advantages, it is an additional structure that is required to be inserted along with an implant, i.e., the femoral stem. Therefore, necessary precautions and care needs to be taken in order to ensure that the centralizer itself is properly positioned, does not degrade over a longer period of time, and does not allow leakage of the PMMA into tissues surrounding the femoral bone. Furthermore, in scenarios where revision surgery is necessary, removing the centralizer and the femoral stem may be challenging. This is because the centralizer is usually placed deep within the femoral bone canal and is surrounded by hardened PMMA bone cement. Such positioning makes the extraction of the centralizer and the femoral stem time-consuming and difficult, thereby increasing potential risks of damage to surrounding tissues and the femoral bone during the extraction.
[5] Therefore, in light of the foregoing discussion, there exists a need to overcome the aforementioned drawbacks.
SUMMARY
[6] The present disclosure provides a cemented femoral stem with detachable centralizer wings. The present disclosure provides a solution to overcome complications that may arise due to requirement to position a centralizer within a bone cavity of a femoral bone for anchoring a femoral stem and properly positioning the femoral stem within the bone cavity. An aim of the present disclosure is to provide the cemented femoral stem where the detachable centralizer wings of the cemented femoral stem function as the centralizer. Thus, there is no requirement to use a centralizer, and it is possible to avoid complications associated with positioning the centralizer within the bone cavity. The centralizer wings are not an integral part of the cemented femoral stem and, based on requirements specific to a subject on which a hip replacement surgery is to be performed, the centralizer wings may be attached to the cemented femoral stem. The cemented femoral stem may include slots into which the centralizer wings may be inserted and slots where the centralizer wings are attached to the cemented femoral stem. The wings facilitate holding the cemented femoral stem in place within the femoral bone cavity and evenly applying a bone cement around the cemented femoral stem.
[7] One or more objectives of the present disclosure is achieved by the solutions provided in the enclosed independent claims. Advantageous implementations of the present disclosure are further defined in the dependent claims.
[8] In an aspect, the present disclosure provides a cemented femoral stem with detachable wings, the cemented femoral stem comprising a femoral stem body and a set of centralizer wings, wherein each centralizer wing of the set of centralizer wings is detachably attached to the femoral stem body. The set of centralizer wings are not integral to the cemented femoral stem. However, the set of centralizer wings are attached to the femoral stem body when the cemented femoral stem is required to be implanted into a femoral bone during a hip replacement surgery. The set of centralizer wings are detached from the femoral stem body when the cemented femoral stem is yet to be implanted.
[9] The cemented femoral stem of the present disclosure offers technical advantages such as capability to inherently embody functionalities of a centralizer without the need to position an actual centralizer in the femoral bone. The set of centralizer wings, once attached to the femoral stem body, fulfil the purposes of the centralizer. The femoral stem body of the cemented femoral stem includes a set of slots. The set of centralizer wings may be inserted through a subset of slots and attached to the femoral stem body locked into another subset of slots. The detachable wings of the cemented femoral stem with allows evenly or uniformly apply a bone cement, such as polymethylmethacrylate (PMMA) bone cement for example, evenly around a distal part of the femoral stem body. This leads to creation of uniform cement mantle around the distal part of the femoral stem body and formation of a strong bond between the femoral bone and the cemented femoral stem.
[10] It is to be appreciated that all the aforementioned implementation forms can be combined. All steps that are performed by the various entities described in the present application, as well as the functionalities described to be performed by the various entities, are intended to mean that the respective entity is adapted to or configured to perform the respective steps and functionalities. It will be appreciated that features of the present disclosure are susceptible to being combined in various combinations without departing from the scope of the present disclosure as defined by the appended claims.
[11] Additional aspects, advantages, features, and objects of the present disclosure would be made apparent from the drawings and the detailed description of the illustrative implementations construed in conjunction with the appended claims that follow.
BRIEF DESCRIPTION OF THE DRAWINGS
[12] The summary above, as well as the following detailed description of illustrative embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present disclosure, exemplary constructions of the disclosure are shown in the drawings. However, the present 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. Wherever possible, like elements have been indicated by identical numbers.
[13] Embodiments of the present disclosure will now be described, by way of example only, with reference to the following diagrams wherein:
FIG. 1 illustrates a perspective view of a cemented femoral stem equipped with wings, in accordance with an embodiment of the present disclosure;
FIG. 2 illustrates a sectional view of the cemented femoral stem of FIG. 1 that is equipped with wings, in accordance with an embodiment of the present disclosure;
FIG. 3 illustrates a sectional view of a femoral stem body of the cemented femoral stem of FIG. 1, in accordance with an embodiment of the present disclosure; and
FIG. 4 illustrates a detailed view of a centralizer wing detachedly attached to the cemented femoral stem of FIG. 1, in accordance with an embodiment of the present disclosure.
[14] In the accompanying drawings, an underlined number is employed to represent an item over which the underlined number is positioned or an item to which the underlined number is adjacent. A non-underlined number relates to an item identified by a line linking the non-underlined number to the item. When a number is non-underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing.
DETAILED DESCRIPTION OF EMBODIMENTS
[15] The following detailed description illustrates embodiments of the present disclosure and ways in which they can be implemented. Although some modes of carrying out the present disclosure have been disclosed, those skilled in the art would recognize that other embodiments for carrying out or practicing the present disclosure are also possible.
[16] FIG. 1 illustrates a perspective view of a cemented femoral stem equipped with wings, in accordance with an embodiment of the present disclosure. With reference to FIG. 1, there is shown the perspective view of a cemented femoral stem 100. The cemented femoral stem 100 may be inserted into a femoral bone cavity of a patient/subject during a hip replacement surgery. The cemented femoral stem 100 includes a femoral stem body 101 and a set of centralizer wings 200. Each centralizer wing of the set of centralizer wings 200 is detachably attached to the femoral stem body 101. In accordance with an embodiment, the set of centralizer wings 200 includes four centralizer wings and the femoral stem body 101 is having four sides. The four centralizer wings (i.e., the set of centralizer wings 200) may be detachably attached to the four sides of the femoral stem body 101. For instance, a first centralizer wing 301 of the set of centralizer wings 200 is detachably attached to a first side of the femoral stem body 101. A second centralizer wing 302 of the set of centralizer wings 200 is detachably attached to a second side of the femoral stem body 101. The set of centralizer wings 200 are attached or assembled to the femoral stem body 101 of the cemented femoral stem 100 prior to initiation of the hip replacement surgery.
[17] Thus, the set of centralizer wings 200 are not an integral part of the femoral stem body 101. The set of centralizer wings 200 acts as a substitute of a conventional centralizer whereby each centralizer wing of the set of centralizer wings 200 may fulfill purposes of the conventional centralizer. This is because the functionalities provided by the set of centralizer wings 200 are same as that of the conventional centralizer. The set of centralizer wings 200 may enhance stability of the cemented femoral stem 100 (once implanted into a femoral bone cavity), cause optimal bone cement mantle between the cemented femoral stem 100 and the femoral bone, and secure a fixation and longevity of the cemented femoral stem 100.
[18] In accordance with an embodiment, a distal part 102 of the femoral stem body 101 includes a set of slots. Each side of the distal part 102 includes a pair of slots of the set of slots. As the femoral stem body 101 is having four sides, the distal part 102 of the femoral stem body 101 includes four sides. As each side of the distal part 102 includes a pair of slots, the set of slots may include eight slots. The pair of slots at each side of the distal part 102 includes a first slot and a second slot. As shown in FIG. 1, a first of the four sides includes a pair of slots, viz., a first slot 102A and a second slot 102B. A second of the four sides includes a first slot 103A and a second slot 103B. Similarly, each of a third side and a fourth side includes a first slot and a second slot (not visible in the perspective view).
[19] FIG. 2 illustrates a sectional view of the cemented femoral stem 100 that is equipped with wings, in accordance with an embodiment of the present disclosure. FIG. 2 is described in conjunction with the elements of FIG. 1. With reference to FIG. 2, there is shown a sectional view of the cemented femoral stem 100 that includes the the set of centralizer wings 200. The pair of slots of the set of slots at each side of the distal part 102 are interconnected. As shown in FIG. 2, the first side of the distal part 102 includes the first slot 102A and the second slot 102B. The first slot 102A and the second slot 102B at the first side of the distal part 102 are interconnected. Furthermore, the first slot 102A is positioned above the second slot 102B. The second side of the distal part 102 includes the first slot 103A and the second slot 103B. The first slot 103A and the second slot 103B at the second side of the distal part 102 are interconnected. Furthermore, the first slot 103A is positioned above the second slot 103B. Similar to the first side and the second side of the distal part 102, the third side of the distal part 102 also includes a first slot and the second slot (not visible in the sectional view). The first slot and the second slot at the third side of the distal part 102 are interconnected. Furthermore, the first slot at the third side of the distal part 102 is positioned above the second slot at the third side of the distal part 102. The fourth side of the distal part 102 also includes a first slot and a second slot (not visible in the sectional view). The first slot and the second slot at the fourth side of the distal part 102 are interconnected. Furthermore, the first slot at the fourth side of the distal part 102 is positioned above the second slot at the fourth side of the distal part 102.
[20] In accordance with an embodiment, each centralizer wing of the set of centralizer wings 200, after insertion through the first slot at each side of the distal part 102 (such as the first slot 102A at the at the first side of the distal part 102), locks into the second slot at the corresponding side of the distal part 102 (such as the second slot 102B at the at the first side of the distal part 102). During an assembly procedure, prior to performance of the hip replacement surgery, each centralizer wing of the set of centralizer wings 200 is inserted through an upper positioned slot, i.e., the first slot at each side of the distal part 102 (such as the first slot 102A at the at the first side of the distal part 102). Thereafter, each centralizer wing of the set of centralizer wings 200 locks into a lower positioned slot, i.e., the second slot at the corresponding side of the distal part 102 (such as the second slot 102B at the at the first side of the distal part 102). The first centralizer wing 301 of the set of centralizer wings 200 is inserted through the first slot 102A at the first side of the distal part 102 and locks into the second slot 102B. The second centralizer wing 302 of the set of centralizer wings 200 is inserted through the first slot 103A at the second side of the distal part 102 and locks into the second slot 103B. A third centralizer wing (not visible in the sectional view10B) of the set of centralizer wings 200 is inserted through the first slot at the third side of the distal part 102 and locks into the second slot at the third side of the distal part 102. A fourth centralizer wing (not visible in the sectional view) of the set of centralizer wings 200 is inserted through the first slot at the fourth side of the distal part 102 and locks into the second slot at the fourth side of the distal part 102.
[21] FIG. 3 illustrates a sectional view of a femoral stem body of the cemented femoral stem 100, in accordance with an embodiment of the present disclosure. FIG. 3 is described in conjunction with the elements of FIG. 1 and FIG. 2. With reference to FIG. 3, there is shown the sectional view of the femoral stem body 101 of the cemented femoral stem 100. The distal part 102 of the femoral stem body 101 includes a set of portions that secure the set of centralizer wings 200 with the femoral stem body 101. Each portion of the set of portions secures a centralizer wing of the set of centralizer wings 200 to a side of the distal part 102. Each side of the distal part 102 of the femoral stem body 101 includes a portion where a centralizer wing of the set of centralizer wings 200 is secured. As the femoral stem body 101 is having four sides, each side includes such a portion.
[22] As shown in FIG. 3, the first side of the distal part 102 of the femoral stem body 101 includes a portion 103. Similarly, each of the other three sides of the femoral stem body 101 includes a portion. Furthermore, there is shown a wall 102C and a wall 102D at the first side of the distal part 102. The wall 102C is inside the first slot 102A at the first side of the distal part 102 and the wall 102D is inside the second slot 102B at the first side of the distal part 102. There is also shown a wall 103C and a wall 103D at the second side of the distal part 102. The wall 103C is inside the first slot 103A at the second side of the distal part 102 and the wall 103D is inside the second slot 103B at the second side of the distal part 102. Additionally, there are walls (not visible in the sectional view) inside the first slot and the second slot at the third side of the distal part 102. Also, there are walls (not visible in the sectional view) inside the first slot and the second slot at the fourth side of the distal part 102.
[23] The portion 103 secures the first centralizer wing 301 of the set of centralizer wings 200. After the insertion of the first centralizer wing 301 through the first slot 102A at the first side of the distal part 102, the first centralizer wing 301 comes into contact with the portion 103 and gets attached to the portion 103. The first centralizer wing 301 is attached such that an end of the first centralizer wing 301 exits through the second slot 102B and gets locked. The portion 103 may include two faces, viz., a first face 104 and a second face 105. The two faces of the portion 103 may be in contact with two faces of the first centralizer wing.
[24] Similarly, a portion at the second side of the distal part 102 of the femoral stem body 101 (not shown in the sectional view) secures the second centralizer wing 302 of the set of centralizer wings 200. After the insertion of the second centralizer wing 302 through the first slot 103A at the second side of the distal part 102, the second centralizer wing 302 comes into contact with the portion at the second side of the distal part 102 and gets attached to the portion. The second centralizer wing is attached such that an end of the second centralizer wing 302 exits through the second slot 103B and gets locked.
[25] A portion at the third side of the distal part 102 of the femoral stem body 101 (not visible in the sectional view) secures the third centralizer wing of the set of centralizer wings 200. After the insertion of the third centralizer wing through the first slot at the third side of the distal part 102, the third centralizer wing comes into contact with the portion at the third side of the distal part 102 and gets attached to the portion. The third centralizer wing is attached such that an end of the third centralizer wing exits through the second slot at the third side of the distal part 102 and gets locked.
[26] A portion at the fourth side of the distal part 102 of the femoral stem body 101 (not visible in the sectional view) secures the fourth centralizer wing of the set of centralizer wings 200. After the insertion of the fourth centralizer wing through the first slot at the fourth side of the distal part 102, the fourth centralizer wing comes into contact with the portion at the fourth side of the distal part 102 and gets attached to the portion. The fourth centralizer wing is attached such that an end of the fourth centralizer wing exits through the second slot at the fourth side of the distal part 102 and gets locked.
[27] FIG. 4 illustrates a detailed view of a centralizer wing that is detachedly attached to the cemented femoral stem 100, in accordance with an embodiment of the present disclosure. FIG. 4 is described in conjunction with the elements of FIG. 1, FIG. 2 and FIG. 3. With reference to FIG. 4, there is shown a detailed view of the first centralizer wing 300. As shown in FIG. 4, the first centralizer wing 301 includes six faces, viz., a first face 201, a second face 202, a third face 203, a fourth face 204, a fifth face 205, and a sixth face 206. Similarly, each of the other three centralizer wings of the set of centralizer wings 200 is having six faces. After the insertion of the first centralizer wing 301 through the first slot 102A at the first side of the distal part 102 of the femoral stem body 101, the first centralizer wing 301 comes into contact with the portion 103 and gets attached to the portion 103 such that the end of the first centralizer wing 301 exits through the second slot 102B and gets locked. The first face 104 of the portion 103 comes into contact with the first face 201 and the second face 105 of the portion 103 comes into contact with the sixth face 206 (as depicted in FIG. 3).
[28] Furthermore, the fourth face 204 of the first centralizer wing 301 comes into contact with the wall 102C of the first slot 102A (i.e., an upper positioned slot) at the first side of the distal part 102 of the femoral stem body 101. The second face 202 of the first centralizer wing 301 comes into contact with the wall 102D of the second slot 102B (i.e., a lower positioned slot) at the first side of the distal part 102 of the femoral stem body 101. Similarly, a fourth face of each of the other three centralizer wings of the set of centralizer wings 200 comes into contact with a wall of an upper positioned slot at each of the other three sides of the distal part 102 of the femoral stem body 101. Also, a second face of each of the other three centralizer wings of the set of centralizer wings 200 comes into contact with a wall of a lower positioned slot at each of the other three sides of the distal part 102 of the femoral stem body 101.
[29] The set of centralizer wings 200, detachably attached to the femoral stem body 101 ensures proper positioning of the femoral stem body 101 within the femoral bone canal by centering the femoral stem body 101 within the femoral bone canal. Furthermore, the set of centralizer wings 200 ensures that bone cement (such as PMMA bone cement) is uniformly or evenly applied around the femoral stem body 101 and, consequently, facilitates formation of a uniform bone cement mantle around the femoral stem body 101. This uniform cement mantle enhances the stability and longevity of the femoral stem body 101. As the set of centralizer wings 200 are attached directly to the distal side 102 of the femoral stem body 101 of the cemented femoral stem 100, center the femoral stem body 101 in the femoral bone canal, as and facilitate formation of a uniform layer of bone cement around the femoral stem body 101, the need to employ a conventional centralizer is no longer present.
[30] Modifications to embodiments of the present disclosure described in the foregoing are possible without departing from the scope of the present disclosure as defined by the accompanying claims. Expressions such as "including", "comprising", "incorporating", "have", "is" used to describe and claim the present disclosure are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural. The word "exemplary" is used herein to mean "serving as an example, instance or illustration". Any embodiment described as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments and/or to exclude the incorporation of features from other embodiments. The word "optionally" is used herein to mean "is provided in some embodiments and not provided in other embodiments". It is appreciated that certain features of the present disclosure, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the present disclosure, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable combination or as suitable in any other described embodiment of the disclosure.
, Claims:We claim:
1. A cemented femoral stem (100) with detachable centralizer wings, the cemented femoral stem (100) comprising:
a femoral stem body (101); and
a set of centralizer wings (200), wherein each centralizer wing of the set of centralizer wings (200) is detachably attached to the femoral stem body (101).
2. The cemented femoral stem (100) as claimed in claim 1, wherein a distal part (102) of the femoral stem body (101) includes a set of slots, and wherein each side of the distal part (102) includes a pair of slots (102A and 102B, 103A and 103B) of the set of slots.
3. The cemented femoral stem (100) as claimed in claim 2, wherein the pair of slots (102A and 102B, 103A and 103B) at each side of the distal part (102) includes a first slot (102A, 103A) and a second slot (102A, 103A).
4. The cemented femoral stem (100) as claimed in claim 3, wherein the pair of slots (102A and 102B, 103A and 103B) of the set of slots at each side of the distal part (102) are interconnected, and wherein the first slot (102A, 103A) is positioned above the second slot (102B, 103B).
5. The cemented femoral stem (100) as claimed in claim 4, wherein each centralizer wing of the set of centralizer wings (200), after insertion through the first slot (102A, 103A), locks into the second slot (102B, 103B).
6. The cemented femoral stem (100) as claimed in claim 2, wherein the distal part (102) includes a set of portions that secures the set of centralizer wings (200) with the femoral stem body (101), and where each portion of the set of portions secures a centralizer wing of the set of centralizer wings (200) to a side of the distal part (102).