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:
IMPACTOR INSTRUMENT FOR A JOINT REPLACEMENT PROCEDURE
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
[001] The present disclosure relates to a surgical device. More particularly, the present disclosure relates to an impactor instrument for a joint replacement procedure.
BACKGROUND OF INVENTION
[002] Total knee replacement is a surgical procedure intended to replace damaged or diseased portions of the knee joint. This procedure is typically considered when conservative treatments like medication and physiotherapy no longer provide adequate relief from pain and immobility caused by conditions, such as, osteoarthritis, rheumatoid arthritis, or traumatic injury. The total knee replacement procedure targets replacing the entire knee joint with prosthetic components (or implants) such as, a femoral component, a tibial component and a tibial liner.
[003] To implant the prosthetic (or implant), an operator requires a combination of instruments to perform the said procedure. For example, during a total knee replacement surgery, an impactor instrument is used to place or insert a knee implant or a part thereof inside the joint portion and an extractor instrument is used to remove the implant from the surgical site. Both impactor and extractor instruments are essential for ensuring the success of orthopedic procedures, providing precision and control during both the placement and removal of the prosthetic implant.
[004] Conventionally, a dedicated impactor instrument is used to insert a component of the implant during the total knee replacement procedure typically includes a femoral component, a tibial component and a patella. Currently, separate impactor and extractor instruments are used for each of these components. Similarly, dedicated impactor and extractor instruments are used for different components of an implant in other joint replacement surgeries.
[005] The use of separate instruments for impaction and extraction and their conventional coupling methods for coupling the attachments for different components of an implant has several disadvantages. Such as switching between the impactor and the extractor instrument increases the overall time and complexity for the surgical procedures. Further, it may also lead to procedural errors, negatively affecting the outcome of the surgery. Further, the increased number of components for the surgery, add to the inventory of the surgery and hence, increases the cost of the surgery. The sterilization requirements for several instruments too add to the complexity and time of the surgery.
[006] A conventional instrument includes a component (e.g., a head component) that provides a supporting surface to couple with a component of an implant for impaction. Typical coupling methods between the said component and the instrument are prone to ingression of debris. One such coupling method includes screw fit mechanism which would require a cavity on the said component and the distal end of the instrument to receive a screw for coupling. The cavity is highly prone to ingression of debris from the procedure towards the distal end of the instrument. The ingression of debris leads to accumulation of contaminants and bacterial growth around the cavity and the said component of the instrument. This poses risks during surgeries and complicates the cleaning and sterilization processes.
[007] Therefore, there arises a need for an impactor instrument which overcomes the problems associated with a conventional instrument.
SUMMARY OF THE INVENTION
[008] 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.
[009] The present disclosure relates to an impactor instrument for a joint replacement procedure, the impactor instrument includes a body having a passage, a handle coupled to the body, an elongated shaft coupled to the handle and residing in the passage of the body, an adaptor and an extension. The handle includes a flat surface at a proximal end capable of receiving an impact. The adaptor includes a proximal portion coupled to the elongated shaft, a distal portion and a plate residing between the proximal portion and the distal portion of the adaptor. The extension includes a proximal portion coupled to the distal portion of the adaptor and a distal portion removably coupled with an attachment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The summary above and the detailed description of descriptive embodiments, is better understood when read in conjunction with the apportioned drawings. For illustration of 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.
[0011] Fig. 1 depicts an isometric view of an impactor instrument 100, according to an embodiment of the present disclosure.
[0012] Fig. 1a depicts a cross-sectional view of the impactor instrument 100, according to an embodiment of the present disclosure.
[0013] Fig. 1b depicts an exploded view of the impactor instrument 100, according to an embodiment of the present disclosure.
[0014] Fig. 1c depicts a perspective view of a body 120 of the impactor instrument 100, according to an embodiment of the present disclosure.
[0015] Fig. 1d depicts a cross-sectional view of the body 120 of the impactor instrument 100, according to an embodiment of the present disclosure.
[0016] Fig. 1e depicts an isometric view of a clamp 160 of the impactor instrument 100, according to an embodiment of the present disclosure.
[0017] Fig. 1f depicts an isometric view of a torsion spring 163 of the impactor instrument 100, according to an embodiment of the present disclosure.
[0018] Fig. 1g depicts an isometric view of a handle 140 and an elongated shaft 130 of the impactor instrument 100, according to an embodiment of the present disclosure.
[0019] Fig. 1h depicts a perspective view of a proximal portion of the handle 140, according to an embodiment of the present disclosure.
[0020] Fig. 2 depicts a cross-sectional view of the coupling between an extension 150 coupled to the adaptor 110, according to an embodiment of the present disclosure.
[0021] Fig. 2a and 2b depicts a perspective view of the adaptor 110, according to an embodiment of the present disclosure.
[0022] Fig. 2c depicts a perspective view of a coil spring 170, according to an embodiment of the present disclosure.
[0023] Fig. 2d depicts an illustrated view of the extension 150, according to an embodiment of the present disclosure
[0024] Fig. 3 depicts a perspective view of the instrument 100 coupled to an attachment 300, according to an embodiment of the present disclosure.
[0025] Fig. 3a depicts a side view of the attachment 300, according to an embodiment of the present disclosure.
[0026] Fig. 3b depicts an isometric view of the attachment 300, according to an embodiment of the present disclosure.
[0027] Fig. 4 depicts a perspective view of the instrument 100 coupled to an attachment 400, according to an embodiment of the present disclosure.
[0028] Fig. 4a depict an isometric view of the attachment 400, according to an embodiment of the present disclosure.
[0029] Fig. 4b depicts an exploded view of the attachment 400, according to an embodiment of the present disclosure.
[0030] Figs. 4c and 4d depict perspective views of a first section 401 of the attachment 400, according to an embodiment of the present disclosure.
[0031] Figs. 4e and 4f depict perspective views of a second section 402 of the attachment 400, according to an embodiment of the present disclosure.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0032] 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.
[0033] 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.
[0034] 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.
[0035] 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.
[0036] The present disclosure relates to an impactor instrument (hereinafter instrument) used during a total knee replacement procedure. In an embodiment, the instrument includes an extension that may be removably coupled to a plurality of attachments. Each attachment couples with a corresponding component of an implant for the total knee replacement. During the total knee replacement surgery, various components of an implant can be impacted using the proposed instrument by simply coupling/decoupling a respective attachment with the instrument as needed. For example, during a total knee replacement surgery, the instrument may function as the impactor for a tibial base plate component, a tibial liner component and the like. Thus, the instrument functions as a universal impactor. The proposed instrument eliminates the requirement of dedicated impactor instruments for various implant components, providing one universal instrument for total knee replacement surgeries. Consequently, the number of instruments needed for a surgery, the complexity associated with sterilizing such multiple instruments and procedural time are reduced. As a result, the overall effectiveness of the procedure is improved. Further, due to the universal functionality, the proposed instrument is usable in a variety of joint replacement procedures. Though the present disclosure has been explained in the context of a total knee replacement, the teachings of the present disclosure may be extended to other joint replacement surgeries without deviating from the scope of the present disclosure.
[0037] Now referring to the figures, Fig. 1 depicts an impactor instrument 100 (or instrument 100), according to an embodiment of the present disclosure. Fig. 1a depicts a cross-sectional view and Fig. 1b depicts an exploded view of the instrument 100. The instrument 100 functions as a universal impactor for impacting various component of an implant (including a trial implant) during a joint replacement procedure. For example, the joint replacement procedure includes a total (or primary) knee replacement procedure. The instrument 100 may be removably coupled with any desired attachment capable of coupling with an implant or a component thereof, as needed, for impacting the implant (or the component thereof) during a joint replacement procedure. For example, during a total knee replacement surgery (any of an initial implantation or a revision procedure), the instrument 100 may be removably coupled with different attachments capable of coupling with, for example, a tibial base plate (including a trial tibial base plate and an actual tibial base plate) and a liner (including a trial line and an actual liner) for impacting the tibial base plate and the liner, respectively. Thus, the same instrument 100 is used to impact multiple components of a total knee implant. The instrument 100 has a proximal end 100a and a distal end 100b. In an embodiment, the instrument 100 includes an adaptor 110, body 120, an elongated shaft 130, a handle 140, an extension 150, a pair of clamps 160, at least one coil spring 170 and a compression spring 132.
[0038] Referring to Figs. 1c and 1d, the body 120 has a proximal end 120a and a distal end 120b. The body 120 has a tubular structure defining a passage 125 extending from the proximal end 120a to the distal end 120b. In an embodiment, the passage 125 has a stepped configuration with a distal section 125b (shown in Figs. 1d) of the passage 125 having a larger diameter than a proximal section 125a of the passage 125. In another embodiment, the proximal section 125a may have a larger diameter than the distal section 125b. The body 120 may be made from a material, such as, without limitations, Precipitation Hardened Stainless Steel, titanium, cobalt-chromium (CoCr), Nitinol or any other medical grade, biocompatible metal. In an embodiment, the body 120 is made of precipitation hardened stainless steel. The body 120 may optionally include a plurality of windows 126. The windows 126 extend longitudinally for at least a partial length of the body 120. The windows 126 reduce the overall weight of the instrument 100, facilitating easy handling of the instrument 100 and reducing manufacturing cost. The windows 126 also provide an inside view of the body 120 and help a medical practitioner to view at least a portion of the passage 125.
[0039] In an embodiment, the body 120 include two pairs of arms 121 towards the distal end 120b, with each pair of arms 121 positioned on a lateral side of the body 120 as depicted in Fig 1c. The arms 121 are coupled to the body 120 using any coupling mechanism, such as, welding, soldering, brazing, riveting, bolting, clamping, etc. The arms 121 extends outward from the body 120. Each of the arms 121 includes an aperture 124. The apertures 124 help in coupling the body 120 with the clamps 160.
[0040] The pair of clamps 160 are coupled to the arms 121 of the body 120 towards the distal end 120b. Fig. 1e depicts one clamp 160 of the pair of clamps 160, according to an embodiment. Each clamp 160 includes a claw 161, a gripping portion 162 and a coupling portion 164. The gripping portion 162 is disposed towards a proximal end of the clamp 160, the claw 161 is disposed towards a distal end of the clamp 160 and the coupling portion 164 is disposed between the claw 161 and the gripping portion 162. The claws 161 are configured to grip a femoral component (e.g., a trial femoral component) during an implantation procedure. The gripping portions 162 enable the user to manipulate the claws 161 to grip and/or release the femoral component as needed during the implantation procedure. A portion of the claws 161 of the clamps 160 extends over the adaptor 110 (depicted in Fig. 1). The claws 161 may have any desired shape, for example, elbow-shaped as depicted in 1e. In an embodiment, a distal end of the claws 161 has a curved portion 161a to provide a better grip to the femoral component. The curved portion 161a has a pre-defined shape, such as, without limitation, J-shape, L-shape, U-shape, etc. In the depicted embodiment, the curved portion 161a is J-shaped. Each clamp 160 is coupled to a respective pair of arms 121 of the body 120 using any coupling mechanism known in the art. According to an embodiment, each clamp 160 is coupled with the corresponding pair of arms 121 using a respective pin 166 (shown Figs. 1 and 1a). The coupling portion 164 of each clamp 160 includes an aperture 165 (see Fig. 1e) configured to receive the pin 166. The coupling portion 164 is disposed in a gap between the corresponding pair of arms 121 and the aperture 165 aligns with apertures 124 of the pair of arms 121. The pin 166 is disposed in the aperture 165 and the apertures 124, thereby coupling the clamp 160 with the respective pair of arms 121.
[0041] Further, each clamp 160 includes a torsion spring 163. The torsion spring 163 is coupled to the clamp 160 and the body 120. The torsion spring 163 stores energy and facilitate the clamp 160 to perform the manipulation function. Fig. 1f illustrates an exemplary torsion spring 163, according to an embodiment. The torsion spring 163 includes a first arm 163a, a second arm 163b and coils 163c provided therebetween. The coils 163c define a cavity 163d. The gripping portion 162 of the clamp 160 includes a recess (not shown) to receive the first arm 163a of the respective torsion spring 163. The second arm 163b rests on the outer surface of the body 120. The cavity 163d aligns with the aperture 165 and the apertures 124 and receives the pin 166. The torsion springs 163 provide a controlled force and resistance when operating the clamps 160. The pins 166 provide additional stability and reinforcement to a joint where the clamps 160 are coupled to the arms 121. The clamps 160 may be made of a material, for example, a medical grade metal. In an exemplary implementation, the clamps 160 are made of stainless steel. The torsion springs 163 and the pins 166 may be made of a medical grade metal, for example, stainless steel.
[0042] When the gripping portions 162 are pressed towards each other, the claws 161 rotate around a respective hinge point (defined by the apertures 124) to move away from each other. As a result, the torsion springs 163 are in a compressed state. When the gripping portions 162 are released, the torsion springs 163 apply a biasing force on the clamps 160, causing the claws 161 to rotate around the respective hinge point towards each other. This facilitates the claws 161 to grip a femoral component during the operation of the instrument 100.
[0043] The handle 140 is provided at the proximal end 100a. The handle 140 is generally cylindrical. The handle 140 includes a head 141 provided at a proximal end of the handle 140 and a threaded portion 144 extending from the head 141 towards a distal end of the handle 140. In an embodiment, the handle 140 is coupled to the body 120 at the proximal end 120a of the body 120 using a threaded mechanism, though any other coupling mechanism may be used. For example, threads 142 are provided on the threaded portion 144 of the handle 140 and are configured to engage with corresponding inner threads 128 provided on an inner surface of the passage 125 of the body 120 towards the proximal end 120a (see Fig. 1d). The handle 140 provides a convenient way to operate the instrument 100. The head 141 enables the user to grip the instrument 100 and operate the instrument 100. The head 141 is rotatable in clockwise and anticlockwise direction. The head 141 is ergonomically designed to provide a secure and comfortable grip to the user. The head 141 may have a flat surface 145 at the proximal end of the handle 140. The user can impact on the flat surface 145 using, for example, a mallet, when inserting a component of an implant, for example, a tibial base plate, a tibial liner, and the like. The handle 140 may be made of a material, such as, without limitation, precipitation hardened stainless steel, titanium, CoCr, nitinol or any other medical grade, biocompatible metal. In an embodiment, the handle 140 is made of precipitation hardened stainless steel. In an embodiment, the head 141 may be removably coupled with an impacting component configured to receive an impact and transfer the impact to the handle 140. The impacting component may include, for example, a slap hammer. The head 141 of the handle 140 includes a slot 143 provided at the proximal end of the handle 140 (see Fig. 1h). The slot 143 is used for coupling with the impacting component. The slot 143 is configured to receive a corresponding coupling portion of the impacting component. The slot 143 may have a shape corresponding to a coupling portion of the impacting component coupled to the handle 140. In an embodiment, the slot 143 has ‘T’ shape. The slot 143 may include a cavity 143a configured to receive a projection of the coupling portion of the impacting component.
[0044] The elongated shaft 130 resides within the passage 125 of the body 120. The elongated shaft 130 extends from the distal end of the handle 140 towards the distal end 120b of the body 120. The elongated shaft 130 is configured to move linearly in response to the rotation of the handle 140. For example, when the handle 140 is rotated in the anticlockwise direction using the head 141, the elongated shaft 130 moves in the proximal direction. When the handle 140 is then rotated in the clockwise direction using the head 141, the elongated shaft 130 moves in a distal direction. Further, the elongated shaft 130 is configured to transmit a force towards an attachment coupled to the distal end 100b of the instrument 100. The elongated shaft 130 may be coupled to the handle 140 using any coupling technique known in the art. In the depicted embodiment, the elongated shaft 130 and the handle 140 are integrally coupled to form an integrated structure. In an embodiment, the elongated shaft 130 is cylindrical, though the elongated shaft 130 may have any other suitable shape. The elongated shaft 130 may be made of a material, such as, without limitation, precipitation hardened stainless steel, titanium, CoCr, nitinol or any other medical grade, biocompatible metal. In an embodiment, the elongated shaft 130 is made of precipitation hardened stainless steel. The elongated shaft 130 may include one or more windows 131 (as seen in Fig. 1g). The windows 131 extend longitudinally for at least partial length of the elongated shaft 130. The windows 131 reduces the overall weight of the instrument 100, facilitating the easy handling of the instrument 100 and reducing the manufacturing cost.
[0045] The elongated shaft 130 is coupled to the adaptor 110 at a distal end of the elongated shaft 130. The adaptor 110 is configured to transmit the force from and/or on the elongated shaft 130 to the extension 150.
[0046] Referring to Figs. 2a and 2b, the adaptor 110 includes a proximal portion 110a and a distal portion 110b and a plate 116 residing therebetween. The proximal portion 110a is disposed towards a proximal end of the adaptor 110 and the distal portion 110b is disposed towards a distal end of the adaptor 110. In an embodiment, the distal portion 110b and the proximal portion 110a are extruded from the plate 116. It should be understood that though the distal portion 110b, the plate 116 and the proximal portion 110a are explained herein as forming an integrated structure (or integrally coupled), it is possible that the distal portion 110b, the plate 116 and the proximal portion 110a may be separate components coupled together using any suitable coupling mechanism. According to an embodiment, the distal portion 110b and the proximal portion 110a are cylindrical, though they may have any other suitable shape. The distal portion 110b and the proximal portion 110a may have the same or different diameters. In the depicted embodiment, the distal portion 110b has a smaller diameter than that of the proximal portion 110a.
[0047] In an embodiment, the proximal portion 110a is coupled to the body 120. For example, a part of the proximal portion 110a of the adaptor 110 is disposed within the distal section 125b of the passage 125 of the body 120 (as depicted in Fig. 1a) and is coupled with the body 120 using, for example, one or more pins 123 (shown in Fig. 1b). The body 120 includes an orifice 127 (see Fig. 1d) provided on each lateral side of the body 120. Each orifice 127 is configured to receive a respective pin 123. Further, the proximal portion 110a includes a slot 115 provided on each lateral side of the proximal portion 110a. Each slot 115 receives a respective pin 123. Thus, each pin 123 passes through a respective orifice 127 of the body 120 and is disposed within a respective slot 115 of the adaptor 110. Each pin 123 is slidable within the respective slot 115, facilitating relative movement between the adaptor 110 and the body 120. The pins 123 and their coupling with the slots 115 ensure that the movement of the adaptor 110 is restricted such that the adaptor 110 does not detach from the body 120 during the operation of the instrument 100. Although, the coupling between the adaptor 110 and the body 120 is described using the pins 123, any other suitable coupling mechanism may be used, instead of or in combination with, the pins 123. The pins 123 may be made of a medical grade, biocompatible metal, for example, stainless steel.
[0048] The plate 116 may have a pre-defined shape such as, but not limited to, rectangular, square, circular, triangular, polygonal, etc. In an embodiment, the plate 116 has a rectangular shape (see Fig. 2 and 2a). The plate 116 includes two grooves 116a provided on lateral sides of the plate 116 and extending towards a central axis of the plate 116. The grooves 116a are positioned such that the interference between the plate 116 and the claws 161 of the clamps 160 is minimum, facilitating smooth movement of the clamps 160 without any obstruction. The plate 116 provides stability and support to the extension 150. The plate 116 includes a proximal surface 116b towards the proximal end of the adaptor 110 and a distal surface 116c towards the distal end of the adaptor 110. The distal surface 116c serves as a platform for the extension 150.
[0049] The proximal portion 110a is coupled to the elongated shaft 130. The proximal portion 110a includes a cavity 111 extending from the proximal end of the adaptor 110 towards the distal end of the adaptor 110 for a partial length of the adaptor 110. The cavity 111 is configured to receive a distal portion of the elongated shaft 130. The cross-sectional shape and cross-sectional dimensions of the cavity 111 are designed such that the elongated shaft 130 is able to move linearly within the cavity 111 during the operation of the instrument 100. The compression spring 132 is disposed in the distal section 125b of the passage 125. In an embodiment, a compression spring 132 (shown in Fig. 1b) is coiled over an outer surface of elongated shaft 130 (as depicted in Fig. 1a). A proximal end of the compression spring 132 is disposed at a proximal end of the distal section 125b of the passage 125. The compression spring 132 facilitates a relative movement between the elongated shaft 130 and the body 120. The compression spring 132 also provides a resilient force to help returning the adaptor 110 to its original position during the operation of the instrument 100. In a default position (e.g., when the instrument 100 is not in use), the compression spring 132 is in a rest (or uncompressed state). When the adaptor 110 is pressed downward, the compression spring 132 is in a compressed state. When the adaptor 110 is released, the compression spring 132 applies a resilient force on the adaptor 110 to move the adaptor 110 back to its original position during the operation of the instrument.
[0050] The adaptor 110 is coupled with the extension 150. In an embodiment, the extension 150 may be removably coupled to the adaptor 110 using any coupling technique such as, but not limited to, fastening, slot-fit, threaded, bolting, snap fit, press fit, taper fit, etc. In another embodiment, the extension 150 may be fixedly coupled to the adaptor 110 using any coupling technique, such as, without limitations, welding, soldering, brazing, riveting, bolting, clamping, etc. Preferably, the adaptor 110 and the extension 150 are coupled such that the coupling between the extension 150 and the adaptor 110 is not exposed to the outside environment, thus preventing contamination. Any accumulation of debris such as, bone cement used during the operation, which leads to contamination seen in conventional devices, is prevented. In an embodiment, the adaptor 110, specifically, the distal portion 110b of the adaptor 110, is coupled with the extension 150 with the help of the at least one coil spring 170. The at least one coil spring 170 removably couples the extension 150 and the adaptor 110.
[0051] In an embodiment, the at least one coil spring 170 includes one coil spring 170. Referring to Fig. 2c, the coil spring 170 includes a plurality of coils. The plurality of coils of the coil spring 170 may have a pre-defined cross-sectional shape, such as, but not limited to, rectangular, triangular, polygonal, circular, oval, etc. In an embodiment, the plurality of coils of the coil spring 170 have a circular cross-section. Due to the circular cross-section, the coil spring 170 increases uniformity into load distribution resulting in consistent radial force and better sealing performance between the extension 150 and the adaptor 110 over time. The plurality of coils of the coil spring 170 may have an axial or canted orientation. In an embodiment, the plurality of coils of the coil spring 170 has canted orientation, i.e., the plurality of coils is slanted with respect to a central plane of the coil spring 170. The canted orientation and circular cross-section of the plurality of coils of the coil spring 170 reduces friction between the two contact surfaces of the extension 150 and the adaptor 110. Further, the canted orientation and circular cross-section of the plurality of coils of the coil spring 170 provides enhanced durability, fatigue resistance, flexibility, deflection, etc. The coil spring 170 may be made from a bio-compatible material such as, without limitation, stainless steel, nickel alloys, copper alloys, high carbon steel, etc. In an embodiment, the coil spring 170 is made of stainless steel.
[0052] The distal portion 110b of the adaptor 110 includes various structural features to facilitate coupling of the adaptor 110 with the extension 150 and the at least one coil spring 170. In an embodiment, the distal portion 110b includes at least one boss 113 as depicted in Fig. 2. The at least one boss 113 is annular. Each of the at least one boss 113 is configured to receive a portion (e.g., a medial circumference) of a respective coil spring 170 of the at least one coil spring 170. In an embodiment, the distal portion 110b includes one boss 113. The boss 113 ensures that the coil spring 170 is locked, preventing a longitudinal movement of the coil spring 170, thereby ensuring a secure coupling of the adaptor 110 with the extension 150. Further, the distal portion 110b includes at least one tab 114. In an embodiment, the distal portion 110b includes two tabs 114 positioned opposite to each other around the surface of the distal portion 110b towards its proximal end. The tabs 114 are used to couple the adaptor 110 with the extension 150 and prevent the rotation of the extension 150 during the operation of the instrument 100. The tabs 114 may be extruded. The top surface of the distal portion 110b includes a chamfered edge 117 configured to facilitate the movement of the adaptor 110 inside the extension 150 during their coupling with each other. The chamfered edge 117 is provided circumferentially on the top surface of the distal portion 110b.
[0053] Now referring to Fig. 2d, in an embodiment, the instrument 100 includes an extension 150 at the distal end 100b. The extension 150 is coupled to the adaptor 110 at the distal end of the adaptor 110. The extension 150 may be made from a material, such as, without limitation, precipitation hardened stainless steel, titanium, CoCr, nitinol or any other medical grade, biocompatible metal. In an embodiment, the extension 150 is made from precipitation hardened stainless steel. The extension 150 may have any shape, such as, without limitations, cuboidal, conical, cylindrical, spherical, circular, etc. In an embodiment, the extension 150 is cylindrical. The extension 150 may have a tubular structure. The extension 150 includes a proximal portion 150a situated towards a proximal end of the extension 150 and a distal portion 150b situated towards a distal end of the extension 150 and a platform 154 therebetween. The proximal portion 150a and the distal portion 150b may have the same or different diameters. In the depicted embodiment, the distal portion 150b has a smaller diameter than that of the proximal portion 150a. The proximal portion 150a of the extension 150 includes a cavity 151. The cavity 151 extends from the proximal end towards the distal end of the extension 150 for a partial length of the proximal portion 150a. The cavity 151 is configured to receive the distal portion 110b of the adaptor 110. The distal portion 110b couples with the cavity 151 via a snap-fit mechanism. The extension 150 may include at least one notch 153. The at least one notch 153 is provided at the proximal end of the extension 150, for example, adjacent to a rim of the cavity 151. Each notch 153 of the at least one notch 153 is configured to receive a corresponding tab 114 of the at least one tab 114 of the adaptor 110. In an embodiment, the extension 150 includes two notches 153. The dimensions and positions of the notches 153 correspond to that of the tabs 114. The coupling of the notches 153 with the tabs 114 prevents any unwanted rotation of the extension 150 with respect to the adaptor 110 during the operation of the instrument 100. Further, the extension 150 includes at least one recess 152. The at least one recess 152 extends circumferentially around the inner surface of the cavity 151. Each of the at least one recess 152 is configured to receive a portion (e.g., lateral circumference) of the corresponding coil spring 170 of the at least one coil spring 170. In an example implementation, the extension 150 includes one recess 152.
[0054] The distal portion 150b of the extension 150 includes a platform 154 and a stub 155. The distal portion 150b of the extension 150 is configured to couple with a plurality of attachments as explained later. The platform 154 provides a support surface to the plurality of attachments. The platform 154 may be generally cylindrical. In an embodiment, the platform 154 has a tapered profile with the diameter of the platform 154 reducing from a distal end to a proximal end of the platform 154. The stub 155 includes a channel 156 extending circumferentially around the stub 155 at a proximal end of the stub 155. The stub 155 is used to removably couple the extension 150 with an attachment. The stub 155 may have a uniform or tapering diameter. In the depicted embodiment, the stub 155 has a uniform diameter. The stub 155 may include a smooth, partially threaded or fully threaded outer surface. In an embodiment, the stub 155 has a smooth outer surface and may be removably coupled with an attachment via a coupling technique, such as, without limitation, snap-fit, friction-fit, tapered fit, etc. In another embodiment, the stub 155 may have external threads (not shown) provided on at least a partial length of the stub 155 and removably coupled with an attachment via a threaded coupling. It should be understood that the distal portion 150b and an attachment may be removably coupled via any other coupling mechanism (e.g., with the help of a fastener) without deviating from the scope of the present disclosure.
[0055] Coupling of the instrument 100 with exemplary attachments are explained below. It should be understood that the attachments explained herein are merely exemplary and teachings of the present disclosure can be extended to any other attachments designed to couple with respective components of an implant.
[0056] Fig. 3 depicts the instrument 100 coupled with an attachment 300, according to an embodiment of the present disclosure. Figs. 3a and 3b depict various views of the attachment 300 according to an embodiment. The attachment 300 may made from a biocompatible material such as, but not limited to, polyether ether ketone (PEEK), polyetherimide (PEI), polyetherimide (PPSU), polysulfone (PSU), polypropylene , etc. In an embodiment, the attachment 300 is made of polypropylene . The attachment 300 is removably coupled with the extension 150 of the instrument 100 using any coupling technique such as, but not limited to, fastening, slot-fit, threaded, welding, bolting, brazing, snap fit, press fit, taper fit, etc. In an embodiment, the extension 150 and attachment 300 are coupled using snap-fit coupling. In an embodiment, the attachment 300 is a tibial liner impactor. The attachment 300 is used to impact a tibial liner (not shown) coupled to the attachment 300. Now, moving to Figs. 3a and 3b, the attachment 300 may have a pre-defined shape such as, without limitations, pyramid, cube, cuboid, cylindrical, hemisphere, frustum, spherical, conical, etc. In an embodiment, the attachment 300 has a generally cylindrical shape. The attachment 300 has a proximal end 300a and a distal end 300b. The attachment 300 includes a slot 301. The slot 301 is provided towards the proximal end 300a of the attachment 300. The slot 301 extends from the proximal end 300a towards the distal end 300b for at least a partial length of the attachment 300. The slot 301 is configured to receive the stub 155 of the extension 150. In an embodiment, the stub 155 of the extension 150 is press-fitted inside the slot 301 of the attachment 300. The length of the slot 301 corresponds to the length of the stub 155. In an embodiment, the attachment 300 includes a cut-out 302 provided at the distal end 300b, defining at least one post 303. The cut-out 302 is configured to receive a corresponding portion of the tibial liner to couple the tibial liner to the cut-out 302, thereby coupling the tibial liner with the attachment 300. In an embodiment, the cut-out 302 defines two posts 303. The posts 303 are positioned at opposite sides of the attachment 300. The cut-out 302 may have a pre-defined shape such as, cuboid, cylindrical, circular, triangular, frustum, etc. In an embodiment, the cut-out 302 is of an inverted frustum shape. The shape and dimensions of the cut-out 302 and the posts 303 are designed according to the tibial liner to be impacted with the help of the instrument 100. For example, the cut-out 302 and the posts 303 are shaped such that they mate perfectly with a proximal surface of the tibial liner, facilitating the instrument 100 to evenly impact the tibial liner. The attachment 300 has a slanted face 304 provided adjacent to either side of the cut-out 302.
[0057] During the total knee surgical procedure, the distal end 300b of the attachment 300 is coupled to the tibial liner positioned at a target site. The handle 140 is impacted, for example, on the flat surface 145 of the handle 140, using an impaction tool such as a mallet. The elongated shaft 130 transfers the impact force to the adaptor 110. The adaptor 110 transfers the impact force to the extension 150, which in turn transfers the impact force to the attachment 300. In response to the instrument receiving the impact the attachment 300 is configured to impact the tibial liner. The impact force on the attachment 300 pushes the tibial liner and securely couples the tibial liner with a tibial base plate fitted inside the tibia. Thus, the instrument 100 impacts the tibial liner with the help of the attachment 300 coupled to the instrument 100.
[0058] Fig. 4 depicts the instrument 100 coupled to the attachment 400, according to an embodiment. Fig. 4a depicts a perspective view of the attachment 400 and Fig. 4b depicts an exploded view of the attachment 400, according to an embodiment. The attachment 400 is removably coupled to the extension 150 of the instrument 100. In an embodiment, the attachment 400 is a tibial base plate impactor. The attachment 400 is used to impact a tibial base plate (not shown) coupled to the attachment 400.
[0059] Moving to Figs. 4a and 4b, the attachment 400 includes a first section 401 and a second section 402. The first section 401 is provided at a proximal end 400a and the second section 402 is provided at a distal end 400b of the attachment 400. The first section 401 may be made of a material, such as without limitation, hardened stainless steel or precipitation hardened stainless steel etc. In an embodiment, the first section 401 is made of precipitation hardened stainless steel. The second section 402 may be made of a material including, but not limited to, polypropylene, PEEK, PPSU, PSU, PEI. In an embodiment, the second section 402 is made of polypropylene. The first section 401 and the second section 402 are coupled using a coupling technique such as, but not limited to, riveting, etc. In an embodiment, the first section 401 and the second section 402 are riveted using at least one rivet 403. In an embodiment, the at least one rivet 403 includes two rivets 403. In another embodiment, the first section 401 and the second section 402 may be fixedly coupled using, for example, pins or screws, etc. The first section 401 is used to couple the attachment 400 with the instrument 100 and the second section 402 is used to couple the attachment 400 with a tibial base plate.
[0060] Referring to Figs. 4c and 4d, the first section 401 has a distal surface 401a and a proximal surface 401b. The first section 401 acts as a supporting structure to the second section 402. In an embodiment, the first section 401 has a polyhedron shape, with its cross-sectional area increasing from a proximal end to a distal end of the second section 402, though it may have any other suitable shape. The distal surface 401a of the first section 401 includes two apertures 406. Each of the two apertures 406 is configured to receive a respective rivet 403. Further, the first section 401 includes at least one orifice 407. In an embodiment, the first section 401 has two orifices 407, with each of the orifice 407 configured to receive a respective dowel 408. The dowels 408 are configured to lock the position of the rivet 403 within the first section 401. The orifices 407 extend from a front to a back side of the first section 401. The attachment 400 includes a slot 409 provided at the proximal end 400a of the attachment 400. For example, the slot 409 is provided on the proximal surface 401b of the first section 401. In an embodiment, the first section 401 is removably coupled to the distal portion 150b of the extension 150. The slot 409 is configured to receives the stub 155 of the extension 150, coupling the attachment 400 and the extension 150 via slot fitting. Though in the depicted embodiment, the extension 150 and the attachment 400 are coupled using the slot-fit mechanism, it should be understood that the extension 150 and the attachment 400 may be removably coupled using any other mechanism. For example, internal threads (not shown) may be provided in the slot 409. The internal threads of the slot 409 may be complementary to and engage with external threads (not shown) provided on the stub 155 of the extension 150, thereby coupling the extension 150 and the attachment 400 via threaded coupling.
[0061] Now referring to Figs. 4e and 4f, the second section 402 includes two apertures 404. The apertures 404 extend for the entire length of the first section 401 and are designed according to the shape and dimensions of the rivets 403. Each aperture 404 aligns with a corresponding aperture 406 of the first section 401 and is configured to receive a corresponding rivet 403, thereby coupling the first section 401 and the second section 402. The second section 402 of the attachment 400 is coupled to the tibial base plate. The second section 402 is shaped and dimensioned according to the tibial base plate. In an embodiment, the second section 402 includes a base 405 towards the proximal end 400a and an extended portion 410 extending from the base 405 to the distal end 400b. The base 405 is configured to act as a support. The base 405 has a predefined shape such as, but not limited to, cylindrical, rectangular, etc. In an embodiment, the base 405 has a rectangular cross-section with curved edges. The extended portion 410 may be similarly shaped as the base 405. In an embodiment, the extended portion 410 has a rectangular cross-section with curved edges. The extended portion 410 has a small cross-sectional area then the base 405. A distal surface of the extended portion 410 couples to a proximal surface of the tibial base plate. In an embodiment, the extended portion 410 may include a depression 411 extending longitudinally for the entire length of the extended portion 410.
[0062] During a total knee replacement procedure, the attachment 400 is coupled to the tibial base plate placed at a target location, for a prepared surface of the tibia. The handle 140, for example, the flat surface 145of the handle 140, is impacted using an impaction tool such a mallet. The impact is transferred to the attachment 400 and thence, to the tibial base plate in similar manner as explained earlier. Due to the impact, the tibial base plate is affixed at the target location.
[0063] The present disclosure provides several advantages over conventional impactor instruments. The proposed impactor instrument acts as a universal impactor instrument in that the proposed instrument is capable of connecting with multiple attachments for impacting various components of an implant during a total knee replacement surgery. The proposed instrument can be used to impact to impact different implant component or trial implant components in the total knee replacement surgery such as, the tibial liner, the tibial base plate, etc. A plurality of impaction attachments can be coupled and decoupled saving time and cost of the surgery. Since different attachments corresponding to different implants and/or components of implants can be easily coupled and decoupled from the proposed instrument, the overall time for the impaction process during the surgeries is reduced. The proposed instrument eliminates the need for separate impactor instruments specialized for a specific component. This decreases the number of instruments required for a surgery, reducing complexity with respect to sterilization of multiple instruments and minimizing the cost. Further, the same instrument can be used to impact components of different sizes and designs by coupling respective attachments (e.g., attachments corresponding to different sizes and shapes of tibial base plates), the instrument is usable for a wider range of components of an implant. Thus, the proposed instrument enhances the effectiveness of the surgical procedure and improves the overall outcome for the patient.
[0064] 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 impactor instrument (100) for a joint replacement procedure, the impactor instrument (100) comprising:
a. a body (120) having a passage (125) extending from a proximal end (120a) to a distal end (120b) of the body (120);
b. a handle (140) coupled to the body (120) at proximal end (120a) of the body (120) and comprising a flat surface at a proximal end (140a) capable of receiving an impact;
c. an elongated shaft (130) coupled to the handle (140) and residing in the passage (125) of the body (120);
d. an adaptor (110) comprising:
i. a proximal portion (110a) coupled to the elongated shaft (130);
ii. a distal portion (110b); and
iii. a plate (116) residing between the proximal portion (110a) and the distal portion (110b); and
e. an extension (150) comprising:
i. a proximal portion (150a) coupled to the distal portion (110b) of the adaptor (110); and
ii. a distal portion (150b) removably coupled with an attachment (300, 400).
2. The impactor instrument (100) as claimed in claim 1, wherein the proximal portion (110a) of the adaptor (110) comprises a cavity (111) provided at a proximal end of the adaptor (110) and configured to receive, and coupled with, the distal end of the elongated shaft (130).
3. The impactor instrument (100) as claimed in claim 1, wherein the distal portion (110b) of the adaptor (110) and the proximal portion (150a) of the extension (150) are coupled using at least one coil spring (170), wherein:
a. the distal portion (110b) of the adaptor (110) comprises at least one boss (113); and
b. the proximal portion (150a) of the extension (150) comprises:
i. a cavity (151) configured to receive the distal portion (110b) of the adaptor (110); and
ii. at least one recess (152) provided on an inner surface of the cavity (151);
c. wherein each coil spring (170) of the at least one coil spring (170) is disposed in a space created by a corresponding boss (113) and a corresponding recess (152).
4. The impactor instrument (100) as claimed in claim 1, wherein the proximal portion (150a) of the extensions (150) comprises at least one notch (153), each notch (153) configured to receive a corresponding tab (114) provided on the distal portion (110b) of the adaptor (110).
5. The impactor instrument (100) as claimed in claim 1, wherein the proximal portion (110a) of the adaptor (110) is at least partially disposed in a distal section (125b) of the passage (125).
6. The impactor instrument (100) as claimed in claim 1, wherein the distal end (120b) of the body (120) and the proximal portion (110a) of the adaptor (110) are coupled using at least one pin (123), wherein;
a. at least one orifice (127) is provided on each lateral side of the distal end (120b) of the body (120); and
b. at least one slot (115) is provided on each lateral side of the proximal portion (110a) of the adaptor (110); and
wherein each orifice (127) of the body (120) and a corresponding slot (115) of the adaptor (110) receive a corresponding pin (123) of the at least one pin (123).
7. The impactor instrument (100) as claimed in claim 1, wherein the distal portion (150b) of the extension (150) comprises a stub (155) removably coupled with the attachment (300, 400), wherein the stub (155) is disposed in a slot (301, 409) provided at a proximal end (300a, 400a) of the attachment (300, 400).
8. The impactor instrument (100) as claimed in claim 7, wherein the stub (155) comprises a channel (156) extending circumferentially around the stub (155).
9. The impactor instrument (100) as claimed in claim 1, wherein the distal portion (150b) comprises a platform (154).
10. The impactor instrument (100) as claimed in claim 1, wherein the handle (140) comprises a slot (143) configured to receive a coupling portion of an impacting component, the slot (143) comprising a cavity (143a) configured to receive a projection of the impacting component.
11. The impactor instrument (100) as claimed in claim 1, wherein the attachment (300) comprises a cut-out (302) provided at a distal end (300b) of the attachment (300), defining at least one post (303), wherein in response to the impactor instrument (100) receiving an impact, the attachment (300) is configured to impact a tibial liner coupled to the cut-out (302) and the at least one post (303).
12. The impactor instrument (100) as claimed in claim 1, wherein the attachment (400) comprises:
a. a first section (401) disposed towards a proximal end (400a) removably coupled to the distal portion (150b) of the extension (150); and
b. a second section (402) disposed towards a distal end (400b) of the attachment (400) and coupled with the first section (401), the second section (402) configured to be coupled with a tibial base plate;
wherein in response to the instrument (100) receiving an impact, the attachment (400) is configured to impact the tibial base plate.