Expandable trial femoral neck and associated method of use

Abstract

To provide: a trial femoral assembly for hip arthroplasty that includes a head, a neck connected to the head, and a stem or broach connected to the neck, where the neck is expandable and collapsible; and an associated method of use.SOLUTION: An embodiment includes a notched rod located within a housing and within a circular lower neck portion. The circular lower neck portion has a tilted spiral cam that interacts with the notched rod to provide movement involving extension or retraction of the neck. A second embodiment includes a bevel gear located on an outer surface of the head that engages a screw located inside the head to move the neck to provide extension or retraction. A third embodiment includes at least three nested, telescoping threaded elements with oppositely handed threads that extend or retract the neck.SELECTED DRAWING: Figure 10

Description

[Technical field]

[0001] The present disclosure generally relates to an extendable trial femoral neck that allows a surgeon to determine the appropriate trial implant (having either a head offset or a stem offset) without dislocating the patient's joint. [Background technology]

[0002] In a total hip arthroplasty, after broaching and / or reaming the femoral canal and reaming the acetabulum, the surgeon will place different trial components and reduce the joint to find the correct range of motion, soft tissue balance, and leg length. The trial components include a trial femoral head and a trial femoral neck, and the surgeon will often try several different offset options to find the best fit for the patient.

[0003] The trial heads are offered in 28mm, 32mm, and 36mm sizes. The 28mm heads are offered in offsets of -5mm, -3.5mm, 0mm, +3.5mm, +7mm, +10.5mm, and +12mm. The 32mm and 36mm trial heads are offered in -3.5mm, 0mm, +3.5mm, +7mm, and +10.5mm.

[0004] The trial necks are offered in three sizes for use with stems 1 / 2 / 3 / 4, 5 / 6 / 7 / 8, and 9 / 10 / 11 / 12. Additionally, standard and lateral options are available for each trial neck size for a total of six.

[0005] Thus, the total SKUs for just the trial heads and trial necks totals 23 SKUs, which represents the majority of the graphics cases utilized in surgery. This large number of SKUs typically includes marked or color-coded trial heads, requiring significant space on the instrument tray. This situation also creates confusion for scrub technicians and surgeons. Thus, there is a need in the art for an adjustable / extendable trial neck, which can be adjusted laterally from standard and / or extended to span a range of trial head sizes. Summary of the Invention

[0006] The following objects, features, advantages, aspects, and / or embodiments are not exhaustive and do not limit the entire disclosure. No single embodiment is required to provide each and every object, feature, or advantage. Any of the objects, features, advantages, aspects, and / or embodiments disclosed herein may be fully or partially integrated with one another.

[0007] A primary object, feature, and / or advantage of the present disclosure is to improve or overcome deficiencies in the art.

[0008] One aspect of the present disclosure is a trial femoral assembly for hip arthroplasty including a head, a neck connected to the head, and a stem or broach connected to the neck, the neck being extendable and foldable.

[0009] Another aspect of the present disclosure is a stem or broach that can move laterally relative to the longitudinal axis of the neck.

[0010] Yet another aspect of the present disclosure is a notched rod located within the housing and within a circular lower neck portion having an angled helical cam that interacts with the notched rod to provide movement with extension or retraction of the neck.

[0011] Another feature of the present disclosure is that the ramped helical cam includes a protrusion that engages an opening in the housing to provide a locking mechanism.

[0012] Yet another aspect of the present disclosure is a bevel gear located on the exterior of the head that engages with a screw located on the interior of the head to move the neck to provide expansion or retraction.

[0013] Yet another feature of the present disclosure is a driver tool that is attached to the bevel pinion gear and rotates the bevel gear when the bevel pinion gear is in contact with the bevel gear.

[0014] Another feature of the present disclosure is a coupling sleeve having a flange member at an outer end which engages a slot internally located within the head.

[0015] Yet another aspect of the present disclosure is a docking sleeve attached to the neck.

[0016] A further feature of the present disclosure is a plurality of nested telescoping threaded elements having reverse threads that allow the neck to expand or retract.

[0017] Yet another feature of the present disclosure is a first telescoping threaded element attached to the stem or broach, a third telescoping threaded element attached to the head, and a second telescoping threaded element located between the first telescoping threaded element attached to the stem or broach and the third telescoping threaded element attached to the head.

[0018] Yet another feature of the present disclosure is a threaded nut that can be advanced up and down the first nested telescopic threaded element, as well as an anti-rotation guide located between the first nested telescopic threaded element and the third nested telescopic threaded element for locking the rotation of the first nested telescopic threaded element and the third nested telescopic threaded element relative to one another.

[0019] Another aspect of the present disclosure is that there is at least 50 percent overlap between the multiple nested telescoping threaded elements at all times, the threaded nut has threads in the same direction as the third nested telescoping threaded element and threads in the opposite direction to the threads of the first nested telescoping threaded element, and the third nested telescoping threaded element does not rotate relative to the first nested telescoping threaded element such that rotation of the head does not affect the overall length of the trial femoral assembly.

[0020] A further feature of the present disclosure is a method for installing a trial femoral assembly in a patient, the trial femoral assembly including a head, a neck connected to the head, and a stem or broach connected to the neck, where the surgeon can lengthen or shorten the neck to reduce the patient's joint and find the preferred range of motion, soft tissue balance, and leg length for the patient.

[0021] Yet another additional object, feature, and / or advantage of the present disclosure is a method for laterally moving the stem or broach relative to the longitudinal axis of the neck.

[0022] Yet another feature of the disclosed method is the utilization of a notched rod located within the housing and within a circular lower neck portion having an angled helical cam that interacts with the notched rod to provide movement of the neck for extension or retraction.

[0023] Yet another feature of the method of the present disclosure is the utilization of a bevel gear located on the exterior surface of the head that engages with a thread located on the interior of the head to provide for the expansion or retraction of the neck.

[0024] Another feature of the method of the present disclosure is utilizing a driver tool that is attached to the bevel pinion gear and rotates the bevel gear when the bevel pinion gear is in contact with the bevel gear.

[0025] A further feature of the present disclosure is the utilization of multiple nested telescoping threaded elements having reverse threads to expand or retract the neck.

[0026] Further objects, features, and / or advantages of the disclosed method involve utilizing a first telescoping threaded element attached to the stem or broach, a third telescoping threaded element attached to the head, and a second telescoping threaded element located between the first telescoping threaded element and the third telescoping threaded element, utilizing a first telescoping threaded element attached to the stem or broach, a third telescoping threaded element attached to the head, and a second telescoping threaded element located between the first telescoping threaded element and the third telescoping threaded element.

[0027] Yet another additional object, feature, and / or advantage of the method of the present disclosure involves utilizing a threaded nut that can advance up and down the first nested telescoping threaded element and an anti-rotation guide located between the first nested telescoping threaded element and the third nested telescoping threaded element to lock the rotation of the first nested telescoping threaded element and the third nested telescoping threaded element relative to one another.

[0028] These and / or other objects, features, advantages, aspects, and / or embodiments will become apparent to those of ordinary skill in the art after reviewing the following brief and detailed description of the drawings. The present disclosure encompasses (a) combinations of the disclosed aspects and / or embodiments, and / or (b) reasonable modifications not shown or described. [Brief description of the drawings]

[0029] Certain embodiments in which the present disclosure may be practiced are illustrated and described in detail, with like reference characters representing like components throughout the several views. The drawings are presented for illustrative purposes and may not be to scale unless otherwise indicated. [Figure 1] 13A-13C are perspective views of the trial femoral neck from left to right, with a first image in a retracted neck position, a second image showing potential neck extension, and a third image in an extended neck position. [Diagram 2] A perspective view of the trial femoral neck from left to right, with the first image in the standard position of the stem relative to the neck, the second image showing a potential lateral offset of the stem, and the third image of the stem shifted laterally relative to the neck. [Diagram 3] FIG. 13 is a front view of a first embodiment of a neck telescoping mechanism trial femoral neck with a cutaway view inside a housing including a ramped helical cam. [Figure 4] 4 is a side view of a first embodiment of a neck telescoping mechanism trial femoral neck with a cross-sectional view of a notched rod interacting with the angled helical cam shown in FIG. 3. FIG. [Diagram 5] FIG. 5 is a side view rotated 90 degrees from FIG. 4 of a first embodiment of a neck telescoping mechanism trial femoral neck, with a cross-sectional view of the notched rod interacting with an inclined helical cam extending from and attached to the head and bottom of the notched rod secured within the circular lower neck enclosure. [Figure 6] FIG. 13 is a perspective view of a second embodiment of a neck extension mechanism trial femoral neck including a driver tool that rotates a bevel pinion gear that engages a bevel gear on the head to extend or shorten the length of the neck. [Figure 7] FIG. 13 is a cutaway perspective view of a second embodiment for a neck extension mechanism trial femoral neck that includes a driver tool that rotates a bevel pinion gear that engages a bevel gear on the head that extends or contracts the length of the neck by engaging a screw located in a coupling sleeve secured in the head. [Figure 8]FIG. 11 is a cutaway perspective view of a third embodiment for a neck telescoping mechanism trial femoral neck including a first nested telescoping threaded element attached to the stem, a third nested telescoping threaded element attached to the head, a second nested telescoping threaded element located between the first and third nested telescoping threaded elements, a threaded nut that can advance up and down the second nested telescoping threaded element, and an anti-rotation guide located between the second and third nested telescoping threaded elements for locking the rotation of the second and third nested telescoping threaded elements relative to each other in a retracted position. [Figure 9] 9 is a cutaway perspective view of a third embodiment for the neck telescoping mechanism trial femoral neck shown in FIG. 8 including a first nested telescoping threaded element attached to the stem, a third nested telescoping threaded element attached to the head, a second nested telescoping threaded element located between the first and third nested telescoping threaded elements, a threaded nut that can advance up and down the second nested telescoping threaded element, and an anti-rotation guide located between the second and third nested telescoping threaded elements for locking the rotation of the second and third nested telescoping threaded elements relative to one another in an extended position. [Figure 10]9 is a cutaway perspective view of a third embodiment for the neck telescoping mechanism trial femoral neck shown in FIG. 8 including a first nested telescoping threaded element attached to the stem, a third nested telescoping threaded element attached to the head, a second nested telescoping threaded element located between the first and third nested telescoping threaded elements, a threaded nut that can advance up and down the second nested telescoping threaded element, and an anti-rotation guide located between the second and third nested telescoping threaded elements for locking the rotation of the second and third nested telescoping threaded elements relative to one another in an extended position.

[0030] Those skilled in the art need not view the nearly infinite number of distinct combinations of features described in the following detailed description in separate figures in order to facilitate an understanding of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] The present disclosure is not limited to what is described herein. Mechanical, electrical, chemical, procedural, and / or other changes may be made without departing from the spirit and scope of the present disclosure. Unless otherwise indicated, features shown or described are not essential to enable the basic operation of the present disclosure.

[0032] A trial femoral neck segment and trial femoral module head are utilized to assess proper component position, joint stability, range of motion, and leg length.

[0033] Referring now to FIG. 1, the trial femoral head and neck assembly is generally indicated by the numeral 10. The adjustable femoral neck portion 12 of the trial femoral head and neck assembly 10 can be adjusted laterally from the standard and / or extended over a range of sizes of the trial trunnion 20. Furthermore, the adjustable femoral neck portion 12 can be extended over a range of sizes, which allows the surgeon to adjust the neck portion 12 while using only one neutral (+0 mm) trial head, allowing the surgeon to easily change the offset while the patient's joint is still being reduced. The extension mechanism of the adjustable femoral neck portion 12 is on the medial portion of the adjustable femoral neck portion 12. It is controlled by a separate instrument that the surgeon can rotate with a click to indicate that it has been adjusted to a new size. The trial trunnion 20 sizes range from -5 mm to +12 mm, so ideally the trial femoral neck 20 can be extended over its entire range. There is a stem 22 for attachment to the femur. Instead of a stem 22, there may be a broach that represents the shape of the final stem implant. There is a first length 14 of the adjustable femoral neck section 12, a visual depiction of the neck extension along the neck axis 16 of the adjustable femoral neck section 12, and a second length 18 of the adjustable femoral neck section 12. The image in FIG. 1 shows how the adjustable femoral neck section 12 lengthens by extending along the neck axis. It extends incrementally so the user can easily see how far they have extended. It is preferably, but not necessarily, laser marked to show the exact dimensions.

[0034] Referring now to FIG. 2, another feature is to make the trial femoral head and neck 10 adjustable so that a change from standard to lateral can be achieved. Currently, there are three different neck lengths, one standard option and one lateral option for each, so a total of six trial necks are required. If the adjustable femoral neck section 12 could be adjusted laterally, the total number of trial necks could be reduced from six to three SKUs. As shown, the stem 22 can be moved from a standard position of the stem 24 relative to the adjustable femoral neck section 12, as shown by the lateral change of the stem 26 relative to the adjustable femoral neck section 20, to a lateral position of the stem 22 relative to the adjustable femoral neck section 28. The trunnion 20 can be moved forward and backward and can be clicked into place so that the user gets tactile feedback to ensure the adjustable femoral neck section 12 is in the proper position. It is preferable that there is an indication of the level of offset.

[0035] 3, 4 and 5 is a first embodiment of a neck extension device generally designated 50. Positioned below the trunnion 20 is a notched rod 60 having a surface that connects to a surface of an inclined helical cam 52. The inclined helical cam 52 is located within a housing 54. This neck extension device 50 provides an extension of a neck portion 66 that cannot be retracted by pressure from tissue or rotation of the trunnion 20, as shown in FIG. 5. The amount of extension 66 of the trunnion 20 can be precisely controlled or precisely "dialed in" based on the dimensions of the inclined helical cam 52. The inclined helical cam 52 includes a protrusion 58 that engages with an opening 59 in the housing 54 to provide a locking mechanism. The longitudinal neck movement is generally designated 62, and the circular helical cam motion that translates to longitudinal neck movement is generally designated 64. The housing 54 is positioned above the neck portion 56, which is cylindrical and surrounds the notched rod 60.

[0036] A second embodiment of the neck extension device is generally indicated at 70 in Figures 6 and 7. There is a driver tool 72 that provides the rotational force. Numerous embodiments of various types of tools can provide this type of rotational force comparable to a hand drill. The driver tool 72 includes an enclosed rotating shaft 74 attached to a bevel pinion gear 78. The direction of rotation of the rotating shaft 74 is indicated at 75. The bevel pinion gear 78 engages with a bevel gear 80 that is attached to the trunnion 20, the rotation of which is indicated at 86. As previously mentioned, the neck portion 56 is positioned at the top of the stem 22.

[0037] As shown in FIG. 7, there is a coupling sleeve 82 that includes a bushing 88 that retains a circular protrusion 89 associated with the bevel pinion gear 78. There is a retaining flange 94 as an upper component of the coupling sleeve 82 that is retained by a slot 96 in the trunnion 20. The bevel gear 80 engages with a rotatable screw 92 within a threaded internal passage 90 to provide the power to extend and retract the trunnion 20. The bevel gear 80 is also connected to the coupling sleeve 82, which provides the proper alignment for the engagement of the bevel pinion gear 78 with the bevel gear 80, as well as providing a support surface to guide the extension and retraction of the neck portion 56, indicated at 62. The coupling sleeve 82 is connected to the neck portion 56 by a connecting screw 84, as shown in FIG. 6.

[0038] A third embodiment of a neck extension device is generally shown at 100 in Figures 8, 9 and 10. The neck extension device 100 includes nested telescopic threaded elements, e.g., three threaded elements having reverse-winding threads. In an exemplary but non-limiting embodiment, a first nested telescopic threaded element 102, e.g., a right-handed thread, has threads that run in one direction, e.g., clockwise, and a nut 108 has matching internal threads that can be threaded up or down the first nested telescopic threaded element 102.

[0039] This nut 108 has an external thread in the opposite coordinate system, e.g., counterclockwise, which preferably engages with a third telescoping threaded element 106 having a matching internal thread, e.g., counterclockwise. This third telescoping threaded element 106 is connected to the first telescoping threaded element 102 via an anti-rotation guide 116 that locks the rotation of the first telescoping threaded element 102 and the third telescoping threaded element 106. When the second telescoping threaded element 104 is rotated, it rides up the first telescoping threaded element 102 and causes the third telescoping threaded element 106 to expand in the same direction. All threaded elements 102, 104, and 106 are nested inside each other and are "telescopic" so that they always maintain a 50% to 100% overlap, providing bending stiffness or this expansion structure. The rotational motion is generally indicated by the numeral 110 of the threaded elements 102 , 104 , and 106 .

[0040] Additionally, because the third nested telescoping threaded element 106 does not rotate relative to the first nested telescoping threaded element 102 forming the base element, rotation of the trunnion trial 20 does not affect the overall length of the neck extension device 100. The longitudinal extension of the second nested telescoping threaded element 104 is indicated by reference numeral 112 and the longitudinal extension of the third nested telescoping threaded element 106 is indicated by reference numeral 114.

[0041] An advantage of this trial femoral head and neck assembly 10 is that the extendable trial neck reduces operating room time by allowing the surgeon to determine the proper trial implant (either head offset or stem offset) without dislocating the joint. The surgeon can use an instrument that can provide tactile feedback by clicking at each offset size, so instead of dislocating the joint, replacing the head, and reducing the joint again, the surgeon can leave the joint reduced and turn the instrument to change the offset size.

[0042] This technique also significantly reduces instrumentation since there can be one trial neck for both the standard neck and the lateral neck. Also, only one neutral offset (+0 millimeter) head is needed for the surgeon to trial. The reduction in instrumentation is especially important in arthroplasty due to the increasing presence of ambulatory surgery centers that do not have the room to store large amounts of instrumentation. Having less instrumentation also makes things much easier for the scrub technician and makes the entire procedure much smoother and quicker.

[0043] From the above, it can be seen that the present disclosure accomplishes at least all of its stated objectives.

[0044] List of reference characters The following list of reference letters and descriptors is neither exhaustive nor limiting, and includes reasonable equivalents. Where possible, elements identified by the following reference letters and / or elements that are more or less ubiquitous in the art can be substituted or supplemented with any element identified by another reference letter.

[0045] [Table 1] Glossary Unless otherwise defined, all technical and scientific terms used above have the same meaning as commonly understood by one of ordinary skill in the art to which embodiments of the present disclosure pertain.

[0046] The terms "a," "an," and "the" include both singular and plural referents.

[0047] The term "or" is synonymous with "and / or" and means any one member or combination of members of a particular list.

[0048] As used herein, the word "exemplary" refers to an example, instance, or illustration, and does not refer to a most preferred embodiment, unless specifically stated otherwise.

[0049] As used herein, the term "about" refers to slight variations in a quantity for any quantifiable variable. Inadvertent errors may occur, for example, through the use of typical measuring techniques or equipment, or from differences in manufacture, source, or purity of the components.

[0050] The term "substantially" refers to a great or significant degree. Thus, given the appropriate context, "substantially" can refer to a plurality, a majority, and / or a supermajority of its quantifiable variable.

[0051] The term "generally" encompasses both "about" and "substantially."

[0052] The term "configured" describes a structure that is capable of performing a task or adopting a particular configuration. The term "configured" can be used interchangeably with other similar phrases such as built, arranged, adapted, manufactured, etc.

[0053] Terms characterizing order, position, and / or orientation are not limiting and are merely referenced according to the figures presented.

[0054] "Invention" is not intended to refer to any single embodiment of a particular invention, but rather encompasses all possible embodiments as described in the specification and claims. The "scope" of the disclosure is defined by the appended claims, along with the full scope of equivalents to which such claims are entitled. The scope of the disclosure is further limited as including any possible modifications to any of the aspects and / or embodiments disclosed herein, which modifications result in other embodiments, combinations, subcombinations, etc., that would be apparent to one of ordinary skill in the art.

Claims

1. 1. A trial femoral assembly for hip arthroplasty, comprising: Head and a neck connected to the head; a stem or broach connected to said neck, said neck being extendable and foldable.

2. The trial femoral assembly for hip arthroplasty according to claim 1 , wherein the stem or broach is movable laterally relative to a longitudinal axis of the neck.

3. 2. The trial femoral assembly for hip arthroplasty according to claim 1, further comprising a notched rod located within the housing and within a circular lower neck portion, the circular lower neck portion having an angled helical cam that interacts with the notched rod to provide movement with expansion or retraction of the neck.

4. The trial femoral assembly for hip arthroplasty according to claim 3 , wherein the ramped helical cam includes a protrusion that engages an opening in the housing to provide a locking mechanism.

5. 2. The trial femoral assembly for hip arthroplasty according to claim 1, further comprising a bevel gear located on an exterior surface of the head that engages with a thread located on an interior surface of the head to move the neck to provide expansion or retraction.

6. 6. The trial femoral assembly for hip arthroplasty of claim 5, further comprising a driver tool attached to a bevel pinion gear for rotating said bevel gear when said bevel pinion gear is in contact with said bevel gear.

7. 6. The trial femoral assembly for hip arthroplasty according to claim 5, further comprising a coupling sleeve having a flange member at an outer end which engages a slot internally located within said head.

8. The trial femoral assembly for hip arthroplasty according to claim 7 , wherein the coupling sleeve is attached to the neck.

9. The trial femoral assembly for hip arthroplasty according to claim 1 , further comprising a plurality of nested telescopic threaded elements having reverse-winding threads for expanding or retracting said neck.

10. 10. The trial femoral assembly for hip arthroplasty of claim 9, further comprising a first telescoping threaded element attached to the stem or broach, a third telescoping threaded element attached to the head, and a second telescoping threaded element located between the first telescoping threaded element attached to the stem or broach and the third telescoping threaded element attached to the head.

11. 11. The trial femoral assembly for hip arthroplasty of claim 10, further comprising a threaded nut that can be advanced up and down the first nested telescopic threaded element, and an anti-rotation guide located between the first and third nested telescopic threaded elements for locking the rotation of the first and third nested telescopic threaded elements relative to one another.

12. 12. A trial femoral assembly for hip arthroplasty according to claim 11, wherein there is at least 50 percent overlap between said plurality of nested telescoping threaded elements at all times, said threaded nut has threads in the same direction as said third nested telescoping threaded element and threads in an opposite direction to the threads of said first nested telescoping threaded element, and said third nested telescoping threaded element does not rotate relative to said first nested telescoping threaded element such that rotation of said head does not affect the overall length of said trial femoral assembly.

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