Patent Description:
Thus, articular side <NUM> is configured to articulate with another joint component (i.e., polymer insert of a tibial component), and bone contacting side <NUM> is configured to be fixed or otherwise secured to a bone (i.e., distal femur). In this regard, each side <NUM>, <NUM> may be optimized for their particular functions-articulation and fixation. For example, fixation side <NUM>, such as surfaces 108a-e and pegs 105a-b, may be provided with a porous structure <NUM> for bony ingrowth, and articular side <NUM> can be coated for wear resistance. It has been found that applying a coating, such as a titanium nitride ("TiN"), to articular surfaces of a metallic implant, such as femoral component <NUM>, can harden the articular interface and reduce friction thereby improving the implant's wear profile. However, coatings of this nature, which may be applied via physical vapor deposition ("PVD"), typically also expose fixation side <NUM> to the coating material which may negatively impact its fixation function. The closest prior art is document <CIT>, which discloses a method of surface coating a femoral component, the femoral component comprising an articular side, a bone facing side, and a peripheral edge defining an intersection between the articular side and bone facing side, the bone facing side having a first planar surface having a first perimeter and a second planar surface having a second perimeter, the perimeters of the first and second planar surfaces defining at least a portion of the peripheral edge of the femoral component. Thus, it may be desirable to shield fixation side <NUM> during the coating process so that it remains free of the coating material. However, properly shielding a fixation side of an implant has proven difficult particularly in mass production of orthopedic implants. Therefore, further improvements are desirable.

According to an aspect of the present disclosure, a fixture for masking a femoral component during a surface coating process is disclosed herein. The femoral component includes an articular side, a bone facing side, and a peripheral edge that defines an intersection between the articular side and bone facing side. The bone facing side has a first planar surface that has a first perimeter and a second planar surface that has a second perimeter. The perimeters of the first and second planar surfaces define at least a portion of the peripheral edge of the femoral component.

The fixture includes a first panel and a second panel. The first panel has a first interface surface that defines a first perimeter of the first panel. The first perimeter of the first panel has substantially the same shape as the first perimeter of the first planar surface of the femoral component. The second panel is connected to the first panel and has a second interface surface that defines a second perimeter of the second panel. The second perimeter of the second panel has substantially the same shape as the second perimeter of the second planar surface of the femoral component. When the fixture is mounted to the bone facing side of the femoral component, the first interface surface engages the first planar surface of the femoral component and covers an entirety thereof, and the second interface surface engages the second planar surface of the femoral component and covers an entirety thereof.

Additionally, the first panel may include a first sidewall that extends downwardly from the first perimeter, and the second panel may include a second sidewall that extends downwardly from the second perimeter. The first and second sidewalls may overlap at least a portion of the peripheral edge of the femoral component when the fixture is mounted to the bone facing side of the femoral component. The first and second sidewalls may be perpendicular to the first and second interface surfaces of the first and second panels, respectively. Further, the first and second sidewalls may intersect the first and second interface surfaces, respectively, at an oblique angle. The oblique angle may be <NUM> degrees. Furthermore, the first and second sidewalls of the respective first and second panels may be each offset from the peripheral edge of the femoral component by a distance. The distance may be <NUM>.

Continuing with this aspect, the first and second panels may be rigidly fixed to each other. Alternatively, the first and second panels may be pivotable relative to each other via a hinge. The hinge may be a flexible hinge. Additionally, the flexible hinge and first and second panels may be integrally connected so as to form a monolithic structure.

Also, the fixture may further include a third panel connected to the second panel. The third panel may include a third interface surface that defines a third perimeter of the third panel. The third perimeter may have substantially the same shape as a third perimeter of a third planar surface of the femoral component. The third panel may also include first and second sheaths that extend from a mask side of the fixture and first and second sheath openings that extend into the respective first and second sheaths from an implant facing side of the fixture. The first and second sheath openings may be configured to respectively receive first and second fixation members extending from the third planar surface of the femoral component when the fixture is mounted to the bone facing side of the femoral component.

Additionally, the fixture may include a fourth and fifth panel that have respective fourth and fifth interface surfaces corresponding to respective fourth and fifth planar surfaces of the femoral component. Further, a recess may intersect the third, fourth, and fifth panels of the fixture so as to define first and second condylar portions of the fixture. The first and second panels may define an anterior flange portion of the fixture. Furthermore, the fixture may include a first tab extending from the first panel, and a second tab extending from the fifth panel. The second tab may extend across the recess.

In yet another embodiment of present disclosure, the first and second perimeters of the first and second panels may be flush with the first and second perimeters of the first and second planar surfaces of the femoral component when the fixture is mounted to the bone facing side of the femoral component.

In yet another aspect of the present disclosure, an assembly prepared for a surface coating process includes a femoral component and a fixture. The femoral component has an articular side, a bone facing side, and a peripheral edge that defines an intersection between the articular side and bone facing side. The bone facing side has a first planar surface having a first perimeter and a second planar surface that has a second perimeter The perimeters of the first and second planar surfaces define at least a portion of a peripheral edge of the femoral component.

The features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings in which:.

As used herein, the term "proximal," when used in connection with a surgical tool or device, or components of a device, refers to the end of the device closer to the user of the device when the device is being used as intended. On the other hand, the term "distal," when used in connection with a surgical tool or device, or components of a device, refers to the end of the device farther away from the user when the device is being used as intended. However, when used in connection with the human body, the term "proximal" means closer to the heart, and the term "distal" means further from the heart. As used herein, the terms "substantially," "generally," "approximately," and "about" are intended to mean that slight deviations from absolute are included within the scope of the term so modified, such as deviations of up to <NUM>% greater or lesser than absolute. All vertical directional terms, such as "up," "down," "above," "below," "vertical," or "height" used in the following description refer only to the orientation of features as depicted in the figure being described. Such directional terms are not intended to suggest that any features of the devices described herein must exist in any particular orientation when constructed.

<FIG> depict a fixture <NUM> according to an embodiment of the present disclosure. Fixture <NUM> is configured to mask fixation side <NUM> of femoral component <NUM> during a coating process, such as PVD of TiN, on articular side <NUM> of femoral component <NUM>.

Fixture or mask <NUM> generally includes a plurality of interconnected panels <NUM>. In the particular embodiment depicted, fixture includes an anterior panel or first panel 118a, an anterior chamfer panel or second panel 118b, a distal panel or third panel 118c, a posterior chamfer panel or fourth panel 118d, and a posterior panel or fifth panel 118e. Anterior and anterior chamfer panels 118a-b generally form an anterior flange portion <NUM> configured to interface with an anterior flange <NUM> of femoral component <NUM>. In this regard, anterior and anterior chamfer panels 118a-b are sized and shaped similarly to anterior surface 108a and anterior chamfer surface 108b of femoral component <NUM>, respectively. Additionally, distal, posterior chamfer, and posterior panels 118c-e are intersected by a recess or notch <NUM> so as to form a first condylar portion 111a corresponding to first condyle 101a and a second condylar portion 111b corresponding to second condyle 101b. In this regard, distal, posterior chamfer, and posterior panels 118c-e are sized and shaped similarly to distal, posterior chamfer, and posterior surfaces 108c-e of femoral component <NUM>, respectively. In other words, a perimeter of each panel 118a-e has a size and shape (i.e., peripheral shape) that is substantially the same as that of a corresponding femoral component bone interface surface 108a-e. Although fixture <NUM> is depicted as including five panels 118a-e, fixture may have more or less panels <NUM> depending on the construction of the femoral component it is configured to mask. For example, in some embodiments, femoral component <NUM> may have only three intersecting planar surfaces <NUM>. In such embodiment, fixture <NUM> may then correspondingly have three interconnected panels <NUM>-one for each surface. Fixture can also be provided in a multitude of different sizes each corresponding to a particular size of femoral component.

Fixture defines a mask side or first side <NUM> and an implant facing side or second side <NUM>. Each panel 118a-e has an implant interface surface <NUM> at the implant facing side of fixture that is generally planar and configured to abut or otherwise rest upon a corresponding planar bone facing surface 108a-e of femoral component <NUM>. In particular, anterior panel 118a includes an anterior interface surface or first planar surface 116a, anterior chamfer panel 118b includes an anterior chamfer interface surface or second planar surface 116b, distal panel 118c includes a distal interface surface or third planar surface 116c, posterior chamfer panel 118d includes a posterior chamfer interface surface or fourth planar surface 116c, and posterior panel 118e includes a posterior interface surface or fifth planar surface 116e. Some femoral components <NUM> may include a porous structure at bone facing side <NUM> of one or more bone interface surface <NUM>. Other femoral components <NUM> may include depressions configured to receive bone cement. In both such porous and cemented femoral component embodiments, the bone facing surfaces <NUM> thereof still nonetheless form a generally planar surface even if each of such surface is partially or wholly constructed of a porous material or has depressions within it. In this regard, panels 118a-e are correspondingly constructed with planar interface surfaces 116a-e.

However, in other embodiments, fixation side <NUM> of femoral component <NUM> may also or exclusively include curved bone facing surfaces or may have planar surfaces or surface features differently arranged than what is depicted in <FIG>. For example, surfaces 108a-e may slope from a centerline of femoral component <NUM> to lateral and medial sides thereof. In such embodiments, each panel <NUM> of a plurality of panels may have corresponding surface features to receive or engage those of the femoral component in a conformal manner. For example, a raised surface feature extending from a fixation side <NUM> of a femoral component <NUM> may have a corresponding depression in a panel of fixture <NUM>. Such exemplary femoral component bone facing/fixation side configurations for which fixture 110can be adapted can be found in <CIT>, which hereby incorporated by reference herein in its entirety.

Additionally, each panel 118a-e includes a sidewall 119a-e that extends along its perimeter and extends downwardly in a direction toward the implant facing side. More particular, first panel 118a includes a first sidewall, second panel includes a second sidewall, third panel includes a third sidewall, fourth panel includes a fourth sidewall, and fifth panel includes a fifth sidewall. Such sidewalls 119a-e together form a skirt <NUM> that traces a periphery of femoral component <NUM> so that, when fixture <NUM> is mounted onto femoral component <NUM>, such skirt <NUM> overlaps a peripheral edge 100a of component <NUM> which helps seal bone facing side <NUM> from the infiltration of a coating material during a coating process.

Femoral component <NUM> may include one or more fixation member <NUM>. In the embodiment depicted, femoral component <NUM> include a first peg or first fixation member 105a and a second peg or second fixation member 105b each extending from distal surface 108c. It may be desirable to also mask fixation members 105a-b from the coating material and to also ensure that fixture <NUM> is not impeded from properly seating onto femoral component <NUM> by fixation members 105a-b. In this regard, fixture <NUM> may include corresponding sheaths 115a-b to house fixation members 105a-b. In the particular embodiment depicted, distal panel 118c includes a first sheath or peg housing 115a and a second sheath or peg housing 115b. Each sheath 115a-b extends away from mask side <NUM> of distal panel 118c and may be cylindrical in shape, for example. At the implant facing side <NUM> of fixture <NUM>, sheath openings 117a-b extend into sheaths 115a-b, respectively, which are each dimensioned to receive a corresponding fixation member 105a-b.

Each panel 118a-e is interconnected with an adjacent panel 118a-e via a hinge <NUM> allowing panels 118a-e to pivot relative to each adjacent panel 118a-e. For example, the hinge <NUM> connecting anterior panel 118a and anterior chamfer panel 118b allows anterior panel 118a and anterior chamfer panel 118b to pivot about a hinge axis relative to each other. In the embodiment depicted, hinges <NUM> are each a flexible hinge that may be integrally connected to panels 118a-e so that panels 118a-e and hinges <NUM> form a monolithic structure. In this regard, fixture <NUM> may be made from a polymer material, such as high-density polyethylene ("HDPE") or analogues thereof, for example, and injection molded or additively manufactured so that hinges <NUM> have a sufficient flexibility. In other embodiments, panels 118a-e may be formed separately and connected together via hinge pins, for example. In such embodiment, fixture <NUM> may be made from a metallic material or polymer material.

Fixture <NUM> also includes an anterior tab or first tab <NUM> and a posterior tab or second tab <NUM> to facilitate user manipulation. In this regard, anterior tab <NUM> is connected to and extends from sidewall 119a of anterior panel 118a, and posterior tab <NUM> is connected to and extends from sidewall 119e of posterior panel 118e. Also, posterior tab <NUM> extends from first condylar portion 111a to second condylar portion 111b across recess <NUM> which helps provide rigidity to the posterior end of fixture <NUM>.

<FIG> depict fixture <NUM> coupled with femoral component <NUM>. In this regard, prior to subjecting femoral component <NUM> to a surface coating process, fixture <NUM> is mounted onto bone facing side <NUM> thereof by gripping tabs <NUM>, <NUM> and moving tabs <NUM>, <NUM> toward each other. This causes panels 118a-e to fold inwardly toward sheaths 115a-b allowing fixture <NUM> to easily fit within bone facing side <NUM> of femoral component <NUM>. Fixture <NUM> is then mounted onto femoral component <NUM> so that distal panel 118c is seated on distal surface 108c and fixation members 105a-b are received in sheaths 115a-b, as best shown in the cross-section of <FIG>. Thereafter, tabs <NUM>, <NUM> are moved apart unfolding fixture <NUM> and so that the remaining panels 118a, 118b, 118d, 118e engage their respective surfaces 108a, 108b, 108d, 108e. Skirt <NUM> of fixture <NUM> extends over the peripheral edge 100a of femoral component <NUM>, as best shown in <FIG> and <FIG>. Once the coating process is completed, tabs <NUM>, <NUM> are moved back toward each other, and fixture <NUM> is lifted away from bone contacting side <NUM> of femoral component <NUM>. This can be done without touching the articular side <NUM> of femoral component <NUM>.

<FIG> depict a fixture <NUM> according to another embodiment of the present disclosure. For ease of review, like elements will be accorded like reference numerals to that of fixture <NUM>, but within the <NUM>-series of numbers. For instance, fixture <NUM> includes a plurality of panels 218a-e each configured to correspond to a respective surface 108a-e of femoral component <NUM>. However, fixture <NUM> also differs from fixture <NUM> in that panels 218a-e are rigidly fixed relative to each other. However, in some embodiments, panels 218a-e may be hingedly connected, as discussed above. Additionally, while panels 218a-e together have the same general shape as that of femoral component <NUM>, panels 218a-e are dimensioned to be larger than femoral component <NUM> so that, when fixture <NUM> is mounted to femoral component <NUM>, a gap G is formed between the peripheral edge 100a of femoral component <NUM> and skirt <NUM>, as best shown in <FIG>. Such gap G may be about <NUM> to <NUM>.

<FIG> depicts a fixture <NUM> according to a further embodiment of the present disclosure. For ease of review, like elements will be accorded like reference numerals to that of fixture <NUM>, but within the <NUM>-series of numbers. For instance, fixture <NUM> includes a plurality of panels 318a-e each configured to correspond to a respective surface 108a-e of femoral component <NUM>. However, fixture <NUM> differs from fixture <NUM> in that sidewalls 219a-e do not extend downwardly and instead terminate so that they are flush with the peripheral edge 100a of femoral component <NUM> when mounted thereto.

<FIG> depicts a fixture <NUM> according to yet another embodiment of the present disclosure. For ease of review, like elements will be accorded like reference numerals to that of fixture <NUM>, but within the <NUM>-series of numbers. For instance, fixture <NUM> includes a plurality of panels 418a-e each configured to correspond to a respective bone contact surface 108a-e of femoral component <NUM>. However, fixture <NUM> differs from fixture <NUM> in that sidewalls 419a-e do not extend downwardly and instead extend outwardly so that they project from the peripheral edge 100a of femoral component <NUM> when fixture <NUM> is mounted thereto. In other words, panels 418a-e together define a perimeter greater than that of femoral component <NUM>.

<FIG> depicts a fixture <NUM> according to an even further embodiment of the present disclosure. For ease of review, like elements will be accorded like reference numerals to that of fixture <NUM>, but within the <NUM>-series of numbers. For instance, fixture <NUM> includes a plurality of panels 518a-e each configured to correspond to a respective surface 108a-e of femoral component <NUM>. However, fixture <NUM> differs from fixture <NUM> in that sidewalls 519a-e are not perpendicular to implant interface surfaces 516a-e. Instead, sidewalls 519a-e extend at a downwardly depending oblique angle Θ relative to their respective bone interface surface 516a-e. Such angle Θ may be about <NUM> degrees, for example. Additionally, sidewalls 519a-e are offset from a peripheral edge 100a of femoral component <NUM> by a first dimension X1 and extends to a free end an additional distance X2. X1 may be about <NUM>, and X2 may be about <NUM>, for example. Such angled sidewalls 519a-e create clearance for coating material to coat side edges of femoral component <NUM> while continuing to mask bone facing side <NUM> thereof.

Claim 1:
A fixture (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) configured for masking a femoral component (<NUM>) during a surface coating process, the femoral component comprising an articular side (<NUM>) , a bone facing side (<NUM>), and a peripheral edge (100a) defining an intersection between the articular side (<NUM>) and bone facing side (<NUM>), the bone facing side having a first planar surface (116a) having a first perimeter and a second planar surface (116b) having a second perimeter, the perimeters of the first and second planar surfaces (116a, 116b) defining at least a portion of the peripheral edge (100a) of the femoral component (<NUM>), the fixture (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) comprising:
a first panel (118a, 218a, 318a, 418a, 518a) having a first interface surface defining a first perimeter of the first panel (118a, 218a, 318a, 418a, 518a), the first perimeter of the first panel (118a, 218a, 318a, 418a, 518a) having substantially the same shape as the first perimeter of the first planar surface (116a) of the femoral component (<NUM>); and
a second panel (118b, 218b, 318b, 418b, 518b) connected to the first panel (118a, 218a, 318a, 418a, 518a) and having a second interface surface defining a second perimeter of the second panel (118b, 218b, 318b, 418b, 518b), the second perimeter of the second panel (118b, 218b, 318b, 418b, 518b) having substantially the same shape as the second perimeter of the second planar surface (116b) of the femoral component (<NUM>),
wherein, when the fixture (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>) is mounted to the bone facing side (<NUM>) of the femoral component (<NUM>), the first interface surface is configured to engage the first planar surface (116a) of the femoral component (<NUM>) and cover an entirety thereof, and the second interface surface is configured to engage the second planar surface (116b) of the femoral component (<NUM>) and cover an entirety thereof.