DESC: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:
FEMORAL IMPACTOR
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-extractor instrument.
BACKGROUND OF THE INVENTION
[002] Partial knee replacement is a surgical procedure intended to replace the affected portion of the knee. Knee joint is the engagement between the femur bone and the tibia bone. The partial knee replacement targets a specific compartment like the medial, lateral, or patella-femoral compartment of the knee joint. A prosthetic is implanted after removing the damaged portion of the knee.
[003] To implant the prosthetic an operator requires a combination of instruments to perform the said procedure. For example, an impactor-extractor instrument is used to place a femoral component of the knee prosthetic inside the knee portion. The impactor-extractor instrument assists in providing a smooth passage to the implant inside the knee. An extractor instrument is used 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 THE INVENTION
[006] The present invention relates to a femoral impactor-extractor instrument for an orthopedic surgical procedure. In an embodiment, the instrument includes a body, a head, an adaptor, and at least one coil spring. The body includes a passage extending from a proximal end to a distal end of the body. The head includes a cavity extending from a proximal end and at least one recess provided on the inner surface of the cavity. The adaptor includes a proximal portion configured to at least partially reside in the passage of the body, a distal portion configured to reside in the cavity of the head, at least one boss provided on the distal portion. The at least one coil spring includes 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 a femoral impactor-extractor instrument 100, according to an embodiment of the present disclosure.
[0010] Fig. 2 depicts a cross-sectional view of the femoral impactor-extractor instrument 100, according to an embodiment of the present disclosure.
[0011] Fig. 3 depicts an exploded view of the femoral impactor extractor instrument 100, according to an embodiment of the present disclosure.
[0012] Fig. 4 depicts a perspective view of a body 102 of the femoral impactor extractor instrument 100, according to an embodiment of the present disclosure.
[0013] Fig. 4a depicts a cross-sectional view of the body 102 of the femoral impactor extractor instrument 100, according to an embodiment of the present disclosure.
[0014] Fig. 5 depicts an isometric view of a clamp 103 of the femoral impactor extractor instrument 100, according to an embodiment of the present disclosure.
[0015] Fig. 6 depicts an isometric view of a torsion spring 103c of the femoral impactor extractor instrument 100, according to an embodiment of the present disclosure.
[0016] Fig. 7 depicts an isometric view of a handle 106 and an elongated shaft 105 of the femoral impactor extractor instrument 100, according to an embodiment of the present disclosure.
[0017] Fig. 7a depicts a perspective view of a proximal portion of the handle 106, according to an embodiment of the present disclosure.
[0018] Fig. 8a depicts a perspective view of a head 101, according to an embodiment of the present disclosure.
[0019] Fig. 8b depicts a cross-sectional view of the head 101, according to an embodiment of the present disclosure.
[0020] Fig. 8c and 8d depict various views of an adaptor 104, according to an embodiment of the present disclosure.
[0021] Fig. 8e depicts an isometric view of a coil spring 107, according to an embodiment of the present disclosure.
[0022] Fig. 8f depicts a cross-sectional view of a coupling between the adaptor 104 and the head 101, according to an embodiment of the present disclosure.
[0023] Fig. 9 depicts the femoral impactor-extractor instrument 100 coupled to a trial femoral component 900, according to an embodiment of the present disclosure
DETAILED DESCRIPTION OF DRAWINGS
[0024] 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.
[0025] 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.
[0026] 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.
[0027] 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.
[0028] The present disclosure relates to a femoral impactor-extractor instrument (hereinafter instrument) for use during a partial knee replacement surgery. According to an embodiment, the instrument includes a head and a body coupled with an adaptor. The present disclosure proposes a coupling mechanism between the head and the adaptor. In an embodiment, the coupling mechanism includes at least one coil spring to couple the head and the adaptor. 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 partial 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 partial 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.
[0029] Now referring to the figures, Fig. 1 depicts a femoral impactor-extractor instrument 100 (or instrument 100), according to an embodiment of the present disclosure. Fig. 2 depicts a cross-sectional view of the instrument 100, according to an embodiment. Fig. 3 depicts an exploded view of the instrument 100, according to an embodiment of the present invention. The instrument 100 is used during a partial 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 partial 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 a retractor during the implantation 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 a head 101 and a body 102.
[0030] Now moving to Figs. 4 and 4a, the body 102 has a proximal end 102a and a distal end 102b. The body 102 has a tubular structure defining a passage 102g extending from the proximal end 102a and the distal end 102b. In an embodiment, the passage 102g has a stepped configuration with a distal section 102g1 of the passage 102g having a larger diameter than a proximal section 102g2 of the passage 102g (see Fig. 4a). In another embodiment, the proximal section 102g2 may have a larger diameter than the distal section 102g1. The body 102 may be made from a bio-compatible 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 102 is made of precipitation hardened stainless steel.
[0031] The body 102 includes one or more flanges 102d at the proximal end 102a. The one or more flanges 102d provides extra stability while operating the instrument 100 during surgical procedures.
[0032] The body 102 may optionally include a plurality of windows 102f. The windows 102f extends at least partially along the length of the body 102. The windows 102f reduce the overall weight of the instrument 100, facilitating easy handling of the instrument 100 and reducing manufacturing cost. Further, the body 102 includes an orifice 102i (see Fig. 4a) provided on each lateral side of the body 102. Each orifice 102i is configured to receive a respective pin 109. In an embodiment, the body 102 includes two orifices 102i.
[0033] In an embodiment, the body 102 include two pairs of arms 102c at the distal end 102b, with each pair of arms 102c positioned on a lateral side of the body 102 as depicted in Fig. 4. The arms 102c are coupled to the body 102 using any coupling mechanism, such as, welding, soldering, brazing, riveting, bolting, clamping, etc. The arms 102c extends outward from the body 102. Each of the arms 102c includes an aperture 102c1. The apertures 102c1 help in coupling the body 102 with a plurality of clamps 103.
[0034] In an embodiment, the instrument 100 includes two clamps 103. The clamps 103 are coupled to the arms 102c of the body 102 towards the distal end 102b. Fig. 5 depicts one clamp 103 of the clamps 103, according to an embodiment. Each clamp 103 includes a claw 103a, a gripping portion 103b and a coupling portion 103e. The gripping portion 103b is disposed at a proximal end of the clamp 103, the claw 103a is disposed at a distal end of the clamp 103 and the coupling portion 103e is disposed between the claw 103a and the gripping portion 103b. The coupling portion 103e is coupled to the body 102. The claws 103a are configured to grip the femoral component (e.g., a trial femoral component or an actual femoral component) during an implantation procedure. The gripping portions 103b enable the user to manipulate the claws 103a to grip and/or release the femoral component as needed during the implantation procedure. A portion of the claws 103a of the clamps 103 extends over the head 101 (depicted in Fig. 1). In an embodiment, a distal end of the claws 103a has a curved portion 103a1 to provide a better grip to the femoral component. The curved portion 103a1 has a pre-defined shape, such as, without limitation, J-shape, L-shape, U-shape, etc. In the depicted embodiment, the curved portion 103a1 is J-shaped. Each clamp 103 of the clamps 103 is coupled to a respective pair of arms 102c using any suitable mechanism known in the art. According to an embodiment, each clamp 103 is coupled with the corresponding pair of arms 102c using a respective pin 103d (shown Fig. 1). The coupling portion 103e of each clamp 103 includes an aperture 103f configured to receive the pin 103d. The coupling portion 103e is disposed in a gap between a corresponding pair of arms 102c and the aperture 103f aligns with apertures 102c1 of the pair of arms 102c. The pin 103d is disposed in the aperture 103f and the apertures 102c1, thereby coupling the clamp 103 with the respective pair of arms 102c.
[0035] Further, each clamp 103 includes a torsion spring 103c. The torsion spring 103c is coupled to the clamp 103 and the body 102. The torsion spring 103c stores energy and facilitate the clamp 103 to perform the manipulation function. Fig. 6 illustrates an exemplary torsion spring 103c, according to an embodiment. The torsion spring 103c includes a first arm 103c1, a second arm 103c2 and coils 103c3 provided therebetween. The coils 103c3 define a cavity 103c4. The gripping portion 103b of the clamp 103 includes a recess (not shown) to receive the first arm 103c1 of the respective torsion spring 103c. The second arm 103c2 rests on the outer surface of the body 102. The cavity 103c4 aligns with the aperture 103f and the apertures 102c1 and receive the pin 103d, thereby coupling the torsion spring 103c with the pair of arms 102c. The torsion springs 103c provide a controlled force and resistance when operating the clamps 103. The pins 103d provide additional stability and reinforcement to a joint where the clamps 103 are coupled to the arms 102c. The clamps 103 may be made of a material, for example, a medical grade metal. In an exemplary implementation, the clamps 103 are made of stainless steel. The pair of torsion springs 103c and the pair of pins 103d may be made of a medical grade metal. In an embodiment, the pair of torsion springs 103c and the pair of pins 103d are made of stainless steel.
[0036] When the gripping portions 103b are pressed towards each other, the claws 103a rotate around a respective hinge point (defined by the apertures 103f) to move away from each other. As a result, the torsion springs 103c are in a compressed state. When the gripping portions 103b are released, the torsion springs 103c apply a biasing force on the clamps 103, causing the claws 103a to rotate around the respective hinge point towards each other. This facilitates the claws 103a to grip a femoral component during the operation of the instrument 100.
[0037] The instrument 100 includes a handle 106 provided at the proximal end 100a. Referring to Fig. 7, the handle 106 is generally cuboidal. The handle 106 includes a knob 106b provided at a proximal end of the handle 106 and a threaded portion 106c extending from the knob 106b towards a distal end of the handle 106. In an embodiment, the handle 106 is coupled to the body 102 at the proximal end 102a using a threaded mechanism, though any other coupling mechanism may be used such as a gear-stopper mechanism. For example, threads 106a are provided on the threaded portion 106c of the handle 106 and are configured to engage with corresponding threads 102h provided on an inner surface of the passage 102g of the body 102 towards the proximal end 102a. The handle 106 provides a convenient way to operate the instrument 100. The knob 106b enables the user to grip the instrument 100 and operate the instrument 100. In an embodiment, the knob 106b is rotatable in clockwise and anticlockwise direction. The knob 106b is ergonomically designed to provide a secure and comfortable grip to the user. The knob 106b may have a flat surface 106d at the proximal end of the handle 106. The flat surface 106d is capable of receiving an impact. The user can impact on the flat surface using, for example, a mallet, when inserting the femoral or any other component. The handle 106 may be made of a material, such as, without limitations, such as, without limitation, precipitation hardened stainless steel, titanium, CoCr, nitinol or any other medical grade, biocompatible metal. In an embodiment, the handle 106 is made of precipitation hardened stainless steel. In an embodiment, the handle 106 may be removably coupled to an impacting component configured to receive an impact and transfer the impact to the handle 106. The impacting component may include, for example, a slap hammer or a strike plate. The knob 106b of the handle 106 may include a slot 106f (shown in Fig. 7a) used for coupling with the impacting component. The slot 106f is configured to receive a corresponding coupling portion of the impacting component. The slot 106f may have a shape corresponding to the coupling portion of the impacting component coupled to the handle 106. In an embodiment, the slot 106f has ‘T’ shape. The slot 106f may include a cavity 106e configured to receive a projection of the coupling portion of the impacting component.
[0038] The instrument 100 includes an elongated shaft 105 residing within the passage 102g of the body 102. The elongated shaft 105 extends from a distal end of the handle 106 towards the distal end 102b of the body 102. The elongated shaft 105 is configured to move linearly (or longitudinally) in response to the rotation of the knob 106b. For example, when the handle 106 is rotated in the anticlockwise direction using the knob 106b, the elongated shaft 105 moves in the proximal direction releasing the force applied on the adaptor 104. When the handle 106 is rotated in the clockwise direction using the knob 106b, the elongated shaft 105 moves in a distal direction to lock the head 101 with the femoral component. Further, the elongated shaft 105 is configured to transmit a force to the head 101 in response to the impact on the flat surface of the handle 106 (as explained later). The elongated shaft 105 is coupled to the handle 106 using any known coupling technique known in the art. For example, a proximal end of the elongated shaft 105 is coupled to a distal end of the handle 106. In an embodiment depicted in Fig. 7, the elongated shaft 105 and the handle 106 are integrally coupled, forming an integrated structure. It should be understood that the handle 106 and the elongated shaft 105 may be separate components coupled using any suitable technique. In an embodiment, the elongated shaft 105 is cylindrical, though the elongated shaft 105 may have any other suitable shape. The elongated shaft 105 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 105 is made of precipitation hardened stainless steel.
[0039] The head 101 serves as a platform for a femoral component during the implantation procedure. Figs. 8a and 8b illustrate the head 101 according to an embodiment. The head 101 has a proximal end 101a and a distal end 101b. The head 101 may have a pre-defined shape such as, without limitation, pyramid, cube, cuboid, sphere, cylindrical, hemisphere, frustum, etc. In an embodiment, the head 101 has an inverted frustum shape such that the diameter of the head 101 reduces from the distal end 101b to the proximal end 101a. A top surface 101d of the head 101, provided at the distal end 101b, may be flat, convex or concave. In the depicted embodiment, the top surface 101d is concave, i.e., the top surface 101d is curved inwards. The top surface 101d contacts a bottom surface of a femoral component and provides support and stability to the femoral component. The head 101 may include one or more grooves 101c on an outer surface of the head 101. The one or more grooves 101c extend longitudinally for at least partial length of the head 101. In the depicted embodiment, the head 101 includes two grooves 101c provided on lateral sides of the head 101 and extending longitudinally for the entire length of the head 101 (as shown in Fig. 8a). Each of the two grooves 101c are positioned on the head 101 such that the interference between the head 101 and the claws 103a of the clamps 103 is minimum, facilitating smooth movement of the clamps 103 without any obstruction. The head 101 may be made of, for example, a biocompatible plastic or any other suitable biocompatible material.
[0040] The instrument 100 includes an adaptor 104. The adaptor 104 is disposed between the head 101 and the body 102 and is used to couple the head 101 and the body 102 together. The adaptor 104 is also coupled to the elongated shaft 105. The adaptor 104 is configured to transmit the force from and/or on the elongated shaft 105 to the head 101.
[0041] Figs. 8c and 8d_depicts the adaptor 104 according to an embodiment. The adaptor 104 includes a distal portion 104a and a proximal portion 104b. The distal portion 104a of the adaptor 104 extends distally from the proximal portion 104b. In an embodiment, the distal portion 104a is extruded from the proximal portion 104b. It should be understood that though the distal portion 104a and the proximal portion 104b are explained herein as forming an integrated structure (i.e., integrally coupled), it is possible that the distal portion 104a and the proximal portion 104b may be separate components coupled together using any suitable coupling mechanism. According to an embodiment, the distal portion 104a and the proximal portion 104b are cylindrical, though they may have any other suitable shape. The distal portion 104a and the proximal portion 104b may have the same or different diameters. In the depicted embodiment, the distal portion 104a has a smaller diameter than that of the proximal portion 104b.
[0042] The proximal portion 104b of the adaptor 104 is coupled to the body 102. The proximal portion 104b is at least partially disposed in the distal section 102g1 of the passage 102g of the body 102. In an embodiment, the proximal portion 104b of the adaptor 104 includes a slot 104d provided on each lateral side of the proximal portion 104b. The slots 104d extend longitudinally (see Fig. 8d). Each slot 104d receives the respective pin 109. For example, each pin 109 passes through a respective orifice 102i of the body 102 and is disposed within a respective slot 104d of the adaptor 104. Each pin 109 is slidable within the respective slot 104d, facilitating relative movement between the adaptor 104 and the body 102. The pins 109 and their coupling with the slots 104d ensure that the movement of the adaptor 104 is restricted such that the adaptor 104 does not detach from the body 102 during the operation of the instrument 100. Although, the coupling between the adaptor 104 and the body 102 is described using the one or more pins 109, any other suitable coupling mechanism may be used, instead of or in combination with, the pins 109. The pins 109 may be made of a medical grade, biocompatible metal, for example, stainless steel. The slot 104d of the adaptor 104 has a larger axial length then that of the orifice 102i of the body 102. This difference in length of the slot 104d allows the adaptor 104 to move in an axial direction determined by the axial length of the slot 104d. Any further movement of the adaptor 104 with respect to the body 102 is restricted by the pins 109.
[0043] The proximal portion 104b is also coupled to the elongated shaft 105. The proximal portion 104b includes a cavity 104c (shown in Fig. 8d) extending from a proximal end of the adaptor 104 towards a distal end of the adaptor 104 for a partial length of the adaptor 104. The cavity 104c is configured to receive a distal portion of the elongated shaft 105 (as shown in Fig. 2). The cross-sectional shape and cross-sectional dimensions of the cavity 104c are designed such that the elongated shaft 105 is able to move linearly within the cavity 104c during the operation of the instrument 100. In an embodiment, the instrument 100 includes a compression spring 102e. The compression spring 102e is disposed in the distal section 102g1 of the passage 102g. In an embodiment, the compression spring 102e is coiled over an outer surface of elongated shaft 105 (as depicted in Fig. 2) such that the pins 109 pass through the compression spring 102e towards a distal end of the compression spring 102e. A proximal end of the compression spring 102e is disposed at a proximal end of the distal section 102g1 of the passage 102g. The compression spring 102e facilitates relative movement of the head 101 and the body 102. The compression spring 102e allows the head 101 to press down for an optimal adjustment of the head 101 with respect to the femoral component and the clamps 103 during a procedure. The compression spring 102e also provides a resilient force to help returning the head 101 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 102e is in a rest (or uncompressed state). When the head 101 is pressed downward, the compression spring 102e is in a compressed state. When the head 101 is released, the compression spring 102e applies a resilient force on the head 101 to move the head 101 back to its original position.
[0044] According to an embodiment, the head 101 and the adaptor 104 are coupled using at least one coil spring 107 as illustrated in Fig. 8f. In an exemplary embodiment, the at least one coil spring 107 includes one coil spring 107. The at least one coil spring 107 provides a tight coupling between the head 101 and the adaptor 104. Since the coupling of the head 101 and the adaptor 104 is not exposed to the outside environment during the operation of the instrument 100, the problem of accumulation of cement and contamination is prevented.
[0045] Fig. 8e depicts the coil spring 107 according to an embodiment. The coil spring 107 is in the shape of a ring. The coil spring 107 includes a plurality of coils. The plurality of coils of the coil spring 107 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 107 have a circular cross-section. Due to the circular cross-section the coil spring 107 increases uniformity into load distribution resulting in consistent radial force and better sealing performance between the head 101 and the adaptor 104 over time. The plurality of coils of the coil spring 107 may have an axial or canted orientation. In an embodiment, the plurality of coils of the coil spring 107 has canted orientation, i.e., the plurality of coils is slanted with respect to a central plane of the coil spring 107. The canted orientation and circular cross-section of the plurality of coils of the coil spring 107 reduces friction between the two contact surfaces of the head 101 and the adaptor 104. Further, the canted orientation and circular cross-section of the plurality of coils of the coil spring 107 provides enhanced durability, fatigue resistance, flexibility, deflection, etc. The coil spring 107 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 107 is made of stainless steel.
[0046] The head 101 and the adaptor 104 are provided with various structural features to facilitate their coupling using the at least one coil spring 107. The proximal end 101a of the head 101 includes the cavity 108. The cavity 108 extends from the proximal end towards the distal end of the head 101 for a partial length of the head 101. The cavity 108 is configured to receive the distal portion 104a of the adaptor 104. The distal portion 104a couples with the cavity 108 via a snap-fit mechanism. The head 101 may include at least one notch 108c provided at the proximal end 101a of the head 101, for example, adjacent to a rim of the cavity 108. Each notch 108c of the at least one notch 108c is configured to receive a corresponding tab 104a2 of the at least one tab 104a2 of the adaptor 104. In an embodiment, the head 101 includes two notches 108c. The dimensions and positions of the at least one notch 108c correspond to that of the at least one tab 104a2. The coupling of the at least one notch 108c with the at least one tab 104a2 prevents any unwanted rotation of the head 101 with respect to the adaptor 104 during the operation of the instrument 100. Further, the head 101 includes at least one recess 108b. The recess 108b extends circumferentially around the inner surface of the cavity 108. Each of the at least one recess 108b is configured to receive a portion (e.g., lateral circumference) of the coil spring 107 of the at least one coil spring 107. The number of recesses 108b correspond to the number of coil springs 107. In an embodiment, the cavity 108 includes one recess 108b.
[0047] Now referring to Fig. 8f, the distal portion 104a is configured to fit within a cavity 108 of the head 101. The distal portion 104a may, optionally, have a tapered shape wherein a diameter of the distal portion 104a decreases towards the distal end of the distal portion 104a. According to an embodiment, a top surface of the distal portion 104a includes a chamfered edge provided circumferentially to facilitate the movement of the adaptor 104 into the head 101 during their coupling with each other. In an embodiment, the distal portion 104a includes at least one boss 104a1 (see Fig. 8c) positioned proximally to the distal end of the distal portion 104a to match the position of the recess 108b provided on the head 101 (see Fig. 8b). Each of the at least one boss 104a1 is configured to receive a portion (e.g., a medial circumference) of the corresponding coil spring 107. Thus, each boss 104a1 and a corresponding recess 108b define a space configure to receive a respective coil spring 107 of the at least one coil spring 107, thereby coupling the head 101 and the adaptor 104. In the depicted embodiment, the distal portion 104a includes one boss 104a1. The boss 104a1 ensures that the coil spring 107 is locked inside the recess 108b. Further, the distal portion 104a includes at least one tab 104a2 provided at a proximal end of the distal portion 104a. Each of the at least one tab 104a2 is configured to fit into a corresponding notch 108c of the at least one notch 108c and is configured to lock the head 101 with the adaptor 104 and prevent its rotation during the operation of the instrument 100. In an embodiment, the distal portion 104a is provided with two tabs 104a2 positioned on opposite sides of the adaptor 104. The distal portion 104a ensures that the coil spring 107 does not move in a distal direction and the head 101 and the adaptor 104 are securely coupled with each other.
[0048] An embodiment of the operation of the instrument 100 is now explained. During the implantation procedure, a surgical incision is made over an affected 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 900 (or femoral component 900). The instrument 100 impacts and extracts the trial femoral component 900. The instrument 100 may be similarly used for impacting and/or extracting a final femoral component.
[0049] The femoral component 900 is coupled to the instrument 100 as depicted in Fig. 9. To couple the femoral component 900 with the instrument 100, first the handle 106 is turned in the anticlockwise direction using the knob 106b. Due to the rotation of the handle 106, the elongated shaft 105 moves in the proximal direction releasing the force applied on the adaptor 104. The head 101 is pressed down a little in the proximal direction, moving the adaptor 104 in the proximal direction. The pins 109 slide in the slot 104d of the adaptor 104 and the compression spring 102e becomes compressed. The femoral component 900 is then placed on top of the head 101. A bottom surface of the femoral component 900 contacts the top surface 101d of the head 101. Before placing the femoral component 900 on the head 101, the gripping portions 103b are pressed towards each other so that the claws 103a move away from each other. Upon placing the femoral component 900, the gripping portions 103b are released so that the claws 103a move towards each other and grip the femoral component 900. For example, the curved portion 103a1 of the claws 103a engages with respective grooves (not shown) provided on the femoral component 900. The handle 106 is then rotated in the clockwise direction using the knob 106b to lock the femoral component 900 with the instrument 100 as depicted in Fig. 4. For example, the clockwise rotation of the knob 106b moves the elongated shaft 105 upwards, pushing the adaptor 104 and the head 101 upwards. The elongated shaft 105 restricts the axial movement of the adaptor 104 and the head 101. This locks the femoral component 900 with the instrument 100. Now the femoral component 900 is ready to be placed inside the compartment. The femoral component 900 is inserted into the compartment at a desired position. The instrument 100 is then impacted at the flat surface 106d of the handle 106 using a hammer. The elongated shaft 105 transmits the force to the head 101 via the adaptor 104, pushing the femoral component 900. The gripping portion 103b is manipulated to release the femoral component 900 from the claws 103a and the instrument 100 is withdrawn. A trial reduction of the knee joint is then performed using the femoral component 900 to assess fit, alignment, stability and a range of motion for an actual femoral implant to be implanted.
[0050] Once the surgeon is satisfied with the trial reduction, the femoral component 900 can be retracted (or extracted) using the instrument 100 as follows. The head 101 is aligned with the femoral component 900 such that the bottom surface of the femoral component 900 contacts the top surface 101d of the head 101. The gripping portion 103b is manipulated such that the claws 103a grip the femoral component 900. The handle 106 is then rotated in the clockwise direction using the knob 106b to tighten the grip of the instrument 100 over the femoral component 900. Now, the femoral component 900 can easily be pulled from the knee.
[0051] The proposed femoral impactor-extractor instrument offers several advantages over conventional instruments. For example, the proposed coupling mechanism between the head 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 head 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 a retractor (or 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.
[0052] 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. A femoral impactor-extractor instrument (100) for an orthopaedic surgical procedure, the femoral impactor extractor instrument (100) comprising:
a. a body (102) comprising a passage (102g) extending from a proximal end (102a) to a distal end (102b) of the body (102);
b. a head (101) comprising:
i. a cavity (108) extending from a proximal end (101a); and
ii. at least one recess (108b) provided on the inner surface of the cavity (108).
c. an adaptor (104) comprising:
i. a proximal portion (104b) configured to at least partially reside in the passage (102g) of the body (102);
ii. a distal portion (104a) configured to reside in the cavity (108) of the head (101); and
iii. at least one boss (104a1) provided on the distal portion (104a); and
d. at least one coil spring (107) having a plurality of coils;
e. wherein each boss (104a1) and a corresponding recess (108b) defines a space configured to receive a respective coil spring (107) of the at least one coil spring (107).
2. The femoral impactor-extractor instrument (100) as claimed in claim 1, wherein the plurality of coils of the at least one coil spring (107) have a canted orientation.
3. The femoral impactor-extractor instrument (100) as claimed in claim 1, wherein the plurality of coils of the at least one coil spring (107) have a circular cross-section.
4. The femoral impactor-extractor instrument (100) as claimed in claim 1, wherein the coil spring (107) is ring shaped.
5. The femoral impactor-extractor instrument (100) as claimed in claim 1, wherein a top surface (101d) of the head (101) is coupled to a bottom surface of a femoral component (900).
6. The femoral impactor-extractor instrument (100) as claimed in claim 1, wherein the body (102) and the proximal portion (104b) of the adaptor (104) are coupled using at least one pin (109), wherein;
a. an orifice (102i) is provided on each lateral side of the body (102); and
b. a slot (104d) is provided on each lateral side of the proximal portion (104b) of the adaptor (104);
wherein each orifice (102i) of the body (102) and a corresponding slot (104d) of the adaptor (104) receive a corresponding pin (109) of the at least one pin (109).
7. The femoral impactor-extractor instrument (100) as claimed in claim 1, wherein the femoral impactor extractor instrument (100) comprises:
a. an elongated shaft (105) residing in the passage (102g) of the body (102) and coupled to the proximal portion (104b) of the adaptor (104); and
b. a handle (106) coupled to the elongated shaft (105) and comprising:
i. a flat surface (106d) provided at a proximal end of the handle (106) and capable of receiving an impact;
ii. a knob (106b); and
iii. a threaded portion (106c) comprising threads (106a) configured to engage with threads (102h) provided on an inner surface of the passage (102g) of the body (102);
c. wherein, in response to the rotation of the knob (106b), the elongated shaft (105) is configured to move longitudinally.
8. The femoral impactor-extractor instrument (100) as claimed in claim 7, wherein the proximal portion (104b) of the adaptor (104) comprises a cavity (104c) configured to receive a distal portion of the elongated shaft (105).
9. The femoral impactor-extractor instrument (100) as claimed in claim 7, wherein the handle (106) comprises a slot (106f) configured to receive a coupling portion of an impacting component, the slot (106f) comprising a cavity (106e) configured to receive a projection of the impacting component.
10. The femoral impactor-extractor instrument (100) as claimed in claim 7, wherein a compression spring (102e) disposed within a distal section (102g1) of the passage (102g) of the body (102) and coiled around the elongated shaft (105).
11. The femoral impactor-extractor instrument (100) as claimed in claim 1, wherein the impactor extractor instrument (100) comprises two clamps (103) coupled to the body (102), each clamp (103) comprising:
a. a claw (103a) configured to grip a femoral component;
b. a gripping portion (103b); and
c. a coupling portion (103e) disposed between the claw (103a) and the gripping portion (103b) and coupled to the body (102).
12. The femoral impactor-extractor instrument (100) as claimed in claim 1, wherein the head (101) comprises at least one notch (108c), each notch (108c) configured to receive a corresponding tab (104a2) of at least one tab (104a2), provided on the distal portion (104a) of the adaptor (104) .
13. The femoral impactor-extractor instrument (100) as claimed in claim 1, wherein the at least one coil spring (107) comprises one coil spring (107).