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 EXTRACTOR INSTRUMENT
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:

 
FILED OF THE INVENTION
[001] The present disclosure relates to a medical device. More particularly, the present disclosure relates to a femoral impactor and extractor.
BACKGROUND OF THE INVENTION
[002] Total knee replacement is a surgical procedure intended to replace damaged or diseased portion 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(s) components (or implants) such as, a femoral component, a tibial component and a tibial liner.
[003] To implant the prosthetic an operator requires a combination of instruments to perform the said procedure. For example, an impactor instrument is used to place a femoral component of the knee prosthetic inside the knee portion. The impactor instrument assists in providing a smooth passage to the implant inside the knee. An extractor instrument is used to retrieve the implant from the knee.
[004] Conventional impactor and extractor instruments include a head portion that provides a surface for supporting the femoral component. The head portion is typically coupled with the rest of the impactor and/or extractor instrument by a screw fit mechanism. The screw fit mechanism requires a cavity on the surface of the head portion to host the screw. The cavity is prone to ingression of debris from the procedure and accumulation of contaminants and bacterial growth around the cavity and the head portion of the instrument. This poses risks during surgeries and complicates the cleaning and sterilization processes.
[005] Therefore, there arises a need for an instrument with improved coupling mechanism to overcome the problems associated with a conventional instrument.
SUMMARY OF INVENTION
[006] The present invention relates to an impactor-extractor instrument for a joint replacement procedure. In an embodiment, the instrument includes a body, an adaptor, a block, and at least one coil spring. The body includes a passage extending from a proximal end to a distal end of the body. The adaptor includes a proximal portion configured to at least partially reside in the passage of the body; a distal portion, at least one boss provided on the distal portion and a plate residing between the proximal portion and the distal portion. The block includes a first surface configured to mate with a distal surface of the plate, a cavity extending from a proximal end towards a distal end of the block and at least one recess provided on an inner surface of the cavity. The at least one coil include a plurality of coils. Each boss and a corresponding recess define a space configured to receive a respective coil spring of the at least one coil spring.
[007] The foregoing features and other features as well as the advantages of the invention will become more apparent from the following detailed description, which proceeds with reference to the accompanying figures.
BRIEF DESCRIPTION OF DRAWINGS
[008] 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.
[009] Fig. 1 depicts an isometric view of an impactor-extractor instrument 100, according to an embodiment of the present disclosure.
[0010] Fig. 1a depicts a cross-sectional view of the impactor-extractor instrument 100, according to an embodiment of the present disclosure.
[0011] Fig. 1b depicts an exploded view of the impactor-extractor instrument 100, according to an embodiment of the present disclosure.
[0012] Fig. 1c depicts a perspective view of a body 120 of the impactor-extractor instrument 100, according to an embodiment of the present disclosure.
[0013] Fig. 1d depicts a cross-sectional view of the body 120 of the impactor-extractor instrument 100, according to an embodiment of the present disclosure.
[0014] Fig. 1e depicts an isometric view of a clamp 160 of the impactor-extractor instrument 100, according to an embodiment of the present disclosure.
[0015] Fig. 1f depicts an isometric view of a torsion spring 163 of the impactor-extractor instrument 100, according to an embodiment of the present disclosure.
[0016] Fig. 1g depicts an isometric view of a handle 140 and an elongated shaft 150 of the impactor-extractor instrument 100, according to an embodiment of the present disclosure.
[0017] Fig. 1h depicts a perspective view of a proximal portion of the handle 140, according to an embodiment of the present disclosure.
[0018] Figs. 2 and 2a depict various views of an adaptor 110, according to an embodiment of the present disclosure.
[0019] Fig. 3 depicts a cross-sectional view of a coupling between the adaptor 110 and the block 150, according to an embodiment of the present disclosure.
[0020] Fig. 4 depicts an isometric view of a coil spring 170, according to an embodiment of the present disclosure.
[0021] Fig. 5 depicts an isometric view of a block 150, according to an embodiment of the present disclosure.
[0022] Fig. 5a depicts an illustrated view of the block 150, according to an embodiment of the present disclosure.
[0023] Fig. 5b depicts a bottom perspective view of the block 150, according to an embodiment of the present disclosure.
[0024] Fig. 6 depicts a trial femoral component 500 mounted on the impactor-extractor instrument 100, according to an embodiment of the present disclosure.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[0025] 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.
[0026] 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.
[0027] 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.
[0028] 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.
[0029] The present disclosure relates to an impactor-extractor instrument (hereinafter, instrument) used for impacting and extracting a femoral component during a total knee replacement surgery. According to an embodiment, the instrument includes a block and an adaptor. The block is coupled to a femoral component. The present disclosure proposes a coupling mechanism between the adaptor and the block. In an embodiment, the coupling mechanism includes at least one coil spring to couple the adaptor and the block. The proposed coupling mechanism prevents ingression of debris into critical areas of the instrument, thus minimizing the accumulation of contaminants and bacterial growth, ultimately improving the overall safety and effectiveness of the total knee replacement surgeries. Also, the coupling mechanism facilitates easier assembly and disassembly, simplifies cleaning procedures, and enhances the efficiency of sterilization processes, ultimately improving the overall safety and effectiveness of knee surgeries. 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.
[0030] Now referring to the figures, Fig. 1 depicts a impactor-extractor 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. In an embodiment, the instrument 100 is used during a total knee replacement surgery for impacting and extracting a femoral component. For example, the instrument 100 is used to grip a femoral component while implanting the femoral component during a total knee replacement surgery (either initial implantation and/or a revision procedure) as well as while extracting a previously implanted femoral component during a revision surgery. In other words, the instrument 100 can function both as an impactor and as an extractor during the surgical procedure. The femoral component may include a trial femoral component used during a trial phase of the knee replacement procedure or a final femoral component that is implanted in a patient’s body. 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, a block 150, a pair of clamps 160, at least one coil spring 170 and a compression spring 132.
[0031] 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.
[0032] 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.
[0033] 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). 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 Fig. 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.
[0034] 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 receive 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.
[0035] 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.
[0036] 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 144 at the proximal end of the handle 140. The user can impact on the flat surface 144 using, for example, a mallet, when inserting a component of an implant, for example, a femoral component, 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 or a strike plate. 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 106c has ‘T’ shape. The slot 143 may include a cavity 143a configured to receive a projection of the coupling portion of the impacting component.
[0037] 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 proximal end 120a 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 releasing the force applied on the adaptor 110. When the handle 140 is then rotated in the clockwise direction using the head 141, the elongated shaft 130 moves in a distal direction to lock the block 150 with the femoral component. Further, the elongated shaft 130 is configured to transmit a force towards the block 150 coupled at the distal end 100b of the instrument 100. The elongated shaft 130 and the handle 140 may be integrally coupled, forming an integrated structure, as described herein. In another embodiment, the elongated shaft 130 and the handle 140 may be separate components coupled using any suitable technique. 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 includes a plurality of 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.
[0038] 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 block 150 coupled to the distal end 100b of the instrument 100.
[0039] Referring to Figs. 2 and 2a, 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.
[0040] In an embodiment, the proximal portion 110a is coupled to the body 120. For example, the proximal portion 110a of the adaptor 110 is at least partially resides with the passage 125, e.g., a part of the proximal portion 110a 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.
[0041] 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 block 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 block 150.
[0042] 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 part of the length of the adaptor 110. The cavity 111 is configured to receive a distal portion of the elongated shaft 130 (as shown in Fig. 1b). 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 head 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.
[0043] In an embodiment, the adaptor 110 is coupled to the block 150 using the at least one coil spring 170 as illustrated in Fig. 3. In the depicted embodiment, the at least one coil spring 170 includes one coil spring 170. The at least one coil spring 170 provides a tight coupling between the block 150 and the adaptor 110. Since the coupling of the block 150 and the adaptor 110 is not exposed to the outside environment during the operation of the instrument 100, the problem of accumulation of cement and contamination is prevented.
[0044] _ Fig. 4 depicts the coil spring 170, according to an embodiment. The coil spring 170 is in the shape of a ring. 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 block 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 block 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.
[0045] The distal portion 110b of the adaptor 110 includes various structural features to facilitate coupling of the adaptor 110 with the block 150 and the at least one coil spring 170. In an embodiment, the distal portion 110b includes at least one boss (e.g., a boss 113) as depicted in Fig. 2. The boss 113 is configured to receive a portion (e.g., a medial circumference) of the coil spring 170. 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 block 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 block 150 and prevent the rotation of the block 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 block 150 during their coupling with each other. The chamfered edge 117 is provided circumferentially on the top surface of the distal portion 110b.
[0046] The block 150 serves as a platform for a femoral component during the implantation procedure. Fig. 5 illustrates the block 150, according to an embodiment. Fig. 5a depicts a cross-sectional view and Fig. 5b depicts a perspective view of the block 150. The block 150 has a proximal surface 151 towards a proximal end 150a and a distal surface 152 towards a distal end 150b. The block 150 may have any suitable shape such as, without limitation, a pyramid, cube, cuboid, sphere, cylindrical, hemisphere, frustum, etc. The block 150 includes two grooves 153 provided on lateral sides of the block 150 and extending towards a central axis of the block 150. The grooves 153 are positioned on the block 150 such that the interference between the block 150 and the claws 161 of the clamps 160 is minimum, facilitating smooth movement of the clamps 160. The grooves 153 are aligned with the grooves 153 of the plate 116. The distal surface 152 contacts a bottom surface of a femoral component and provides support and stability to the femoral component. The distal surface 152 may be flat, convex or concave. In an embodiment, the distal surface 152 includes two sections 152a sloping away from the central axis of the block 150, such that the block 150 is in the shape of a triangular prism. Each section 152a contacts a bottom surface of a respective condyle of the femoral component. The slanted design of the distal surface 152 provides a more stable support to the femoral component. The proximal surface 151 may be flat. The proximal surface 151 mates with the distal surface 116c of the plate 116. The block 150 incudes a cavity 154 provided on the proximal surface 151. The cavity 154 extends from the proximal end 150a of the block 150 towards the distal end 150b of the block 150 for a partial length of the block 150 (see Figs. 5a and 5b). The cavity 154 is configured to receive the distal portion 110b of the adaptor 110. The cavity 154 of the block 150 includes at least one recess 155 extending circumferentially around the inner surface of the cavity 154 of the block 150. Each of the at least one recess 155 is configured to receive a portion (e.g., lateral circumference) of the coil spring 170 of the at least one coil spring 170. Each boss 113 provided in the adaptor 110 and a corresponding recess 155 provided in the block 150 define a space configured to receive a corresponding coil spring 170 of the at least one coil 170. Thus, each coil spring 170 is disposed in a space enclosed by a corresponding boss 113 provided in the adaptor 110 and a corresponding recess 155 provided in the block 150. The number of recesses 155 correspond to the number of coil springs 170. In an embodiment, the cavity 154 includes one recess 155. Further, the cavity 154 may include at least one notch 156. Each notch 156 of the notches 156 is configured to receive a corresponding tab 114 of the tabs 114 of the adaptor 110. The coupling of the notches 156 with the tabs 114 prevents any unwanted rotation of the block 150 with respect to the adaptor 110 during the operation of the instrument 100. Fig. 3 depicts a cross-sectional view of the coupling between the adaptor 110 and the block 150 with the coil spring 170 disposed in the recess 155 and the boss 113.
[0047] An embodiment of the operation of the instrument 100 is now explained. During the implantation procedure, a surgical incision is made over a damaged or diseased compartment of the patient’s knee joint. Soft tissues are dissected to expose the compartment. Any remaining articular cartilage in the compartment is removed to create a smooth surface for the implantation. The femoral condyle of the compartment is prepared to receive a trial femoral component 500 (or femoral component 500). The instrument 100 is used to impact and extract the trial femoral component 500. The instrument 100 may be similarly used for impacting and/or extracting a final femoral component.
[0048] The femoral component 500 is coupled to the instrument 100. To couple the femoral component 500 with the instrument 100, first the handle 140 is turned in the anticlockwise direction using the head 141. Due to the rotation of the handle 140, the elongated shaft 130 moves in the proximal direction releasing the force applied on the adaptor 110. The block 150 is pressed down little in the proximal direction moving the adaptor 110 in the proximal direction. The pins 123 slides in the slot 115 of the adaptor 110 in the proximal direction and the compression spring 132 becomes compressed. The femoral component 500 is then placed on the distal surface 152 of the block 150. Each condyle 501 of the femoral component 500 rests on a respective section 152a of the distal surface 152. Before placing the femoral component 500 on the block 150, the gripping portion 162 are pressed towards each other so that the claws 161 moves away from each other. Upon placing the femoral component 500, the gripping portions 162 are released so that the claws 161 move towards each other and grip the femoral component 500. For example, the curved portion 161a of the claws 161 engage with respective grooves (not shown) provided on the femoral component 500. The head 141 of handle 140 is then rotated in the clockwise direction using the head 141 to lock the femoral component 500 with the instrument 100 as depicted in Fig. 6. For example, the clockwise rotation of the handle 140 moves the elongated shaft 130 upwards, pushing the adaptor 110 and the block 150 upwards. The elongated shaft 130 restricts the axial movement of the adaptor 110 and the block 150. This locks the femoral component 500 with the instrument 100. Now the femoral component 500 is ready to be placed inside the compartment. The femoral component 500 is then inserted into the compartment at a desired position. The instrument 100 is then impacted at the flat surface 144 of the handle 140 using a hammer. The elongated shaft 130 transmits the force to the block 150 via the adaptor 110, pushing the femoral component 500. The gripping portion 162 is manipulated to release the femoral component 500 from the claws 161 and the instrument 100 is withdrawn. A trial reduction of the knee joint is then performed using the femoral component 500 to assess fit, alignment, stability and a range of motion for an actual femoral implant to be implanted.
[0049] Once the surgeon is satisfied with the trial reduction, the femoral component 500 can be retracted using the instrument 100 as follows. The block 150 is aligned with the femoral component 500 such that the bottom surface of the femoral component 500 contacts the distal surface 152 of the block 150. The gripping portion 162 is manipulated such that the claws 161 grip the lateral sides of the femoral component 500. The head 141 of the handle 140 then rotated in the clockwise direction using the head 141 to tighten the grip of the instrument 100 over the femoral component 500. Now, the femoral component 500 can easily be pulled from the knee.
[0050] The proposed femoral impactor extractor instrument offers several advantages over conventional instruments. For example, the proposed coupling mechanism between the block and the adaptor of the proposed instrument via the at least one coil spring, prevents ingress of cement and debris during the implantation procedure unlike the conventional instruments. Further, the proposed coupling mechanism minimizes the accumulation of contaminants and bacterial growth within the proposed instrument. This reduces the risk of surgical site infections and enhances the overall hygiene. Further, the proposed coupling mechanism facilitates easier assembly and disassembly of the block from the rest of the instrument, which simplifies cleaning procedures and enhances the efficiency of the sterilization process. Further, the same instrument can be used both as an impactor and an extractor, thereby improving the functionality of the instrument. With improved hygiene and functionality, the proposed instrument increases the safety and effectiveness of the implantation procedure and leads to better patient outcome.
[0051] 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-extractor instrument (100) for a joint replacement procedure, the instrument (100) comprising:
a. a body (120) comprising a passage (125) extending from a proximal end (120a) to a distal end (120b) of the body (120);
b. an adaptor (110) comprising:
i. a proximal portion (110a) configured to at least partially reside in the passage (125) of the body (120);
ii. a distal portion (110b);
iii. at least one boss (113) provided on the distal portion (110b); and
iv. a plate (116) residing between the proximal portion (110a) and the distal portion (110b); and
c. a block (150) comprising:
i. a proximal surface (151) configured to mate with a distal surface (116c) of the plate (116);
ii. a cavity (154) extending from a proximal end (150a) towards a distal end (150b) of the block (150); and
iii. at least one recess (155) provided on the inner surface of the cavity (154); a
d. at least one coil spring (170) having a plurality of coils;
e. wherein each boss (113) and a corresponding recess (155) define a space configured to receive a respective coil spring (170) of the at least one coil spring (170).
2. The impactor-extractor instrument (100) as claimed in claim 1, wherein the plurality of coils of the at least one coil spring (170) have a canted orientation.
3. The impactor-extractor instrument (100) as claimed in claim 1, wherein the plurality of coils of the at least one coil spring (170) have a circular cross-section.
4. The impactor-extractor instrument (100) as claimed in claim 1, wherein the coil spring (170) is ring shaped.
5. The impactor-extractor instrument (100) as claimed in claim 1, wherein a distal surface (152) of the block (150) is coupled to a bottom surface of a femoral component (500).
6. The impactor-extractor instrument (100) as claimed in claim 5, wherein the distal surface (152) includes two sections (152a) sloping away from a central axis of the block 150.
7. The impactor-extractor instrument (100) as claimed in claim 1, wherein the body (120) and the proximal portion (110a) of the adaptor (110) are coupled using at least one pin (123), wherein;
a. an orifice (127) is provided on each lateral side of the body (120); and
b. a slot (115) is provided on each lateral side of the proximal portion (110a) of the adaptor (110);
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).
8. The impactor-extractor instrument (100) as claimed in claim 1, wherein the impactor extractor instrument (100) comprises:
a. an elongated shaft (130) residing in the passage (125) of the body (120) and coupled to the proximal portion (110a) of the adaptor (110); and
b. a handle (140) coupled to the elongated shaft (130) and comprising:
i. a flat surface (144) provided at a proximal end of the handle (140) and capable of receiving an impact;
ii. a head (141) rotatable in a clockwise or an anticlockwise direction; and
iii. a threaded portion (144) comprising threads (142) configured to engage with threads (142) provided on an inner surface of the passage (125) of the body (120);
c. wherein, in response to the rotation of the head (141), the elongated shaft (130) is configured to move longitudinally.
9. The impactor-extractor instrument (100) as claimed in claim 8, wherein the proximal portion (110a) of the adaptor (110) comprises a cavity (111) configured to receive a distal portion of the elongated shaft (130).
10. The impactor-extractor instrument (100) as claimed in claim 8, 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-extractor instrument (100) as claimed in claim 7, wherein a compression spring (132) within a distal section (125b) of the passage (125) of the body (120) and coiled around the elongated shaft (130).
12. The impactor-extractor instrument (100) as claimed in claim 1, wherein the impactor extractor instrument (100) comprises two clamps (160) coupled to the body (120), each clamp (160) comprising:
a. a claw (161) configured to grip a femoral component;
b. a gripping portion (162); and
c. a coupling portion (164) disposed between the claw (161) and the gripping portion (162) and coupled to the body (120).
13. The impactor-extractor instrument (100) as claimed in claim 1, wherein the block (150) comprises at least one notch (156), each notch (156) configured to receive a corresponding tab (114) of at least one tab (114) of the adaptor (110).
14. The impactor extractor instrument (100) as claimed in claim 1, wherein the at least one coil spring (170) comprises one coil spring (170).