Implant for bone fixation

This U.S. non-provisional patent application is a continuation-in-part of co-pending patent application Ser. No. 14/616,239 filed Feb. 6, 2015 titled “Foot Implant For Bone Fixation”, which claimed the benefit of and/or priority under 35 U.S.C. § 119(e) to U.S. provisional patent application Ser. No. 61/936,644 filed Feb. 6, 2014 titled “Foot Implant For Bone Fixation,” the entire contents of each of which is specifically incorporated herein by reference.

The present invention relates to implants for fixation of human bones, and particularly, to implants for fixation of bones of the foot. More particularly, the present invention relates to implants for internal fixation of calcaneus, tarsal, and metatarsal bones of the foot.

Background Information

There are many reasons why surgeries are performed on the bones of the foot. Some foot surgeries such as osteotomies are performed to correct angular deformities. Other foot surgeries are performed to mend a fracture or to re-align or reposition bones of the foot. In these surgical procedures and others, two bone portions must be joined or otherwise connected to each other so as to be fixed in a desired position and, eventually fuse. This may be accomplished by a foot bone implant.

A foot bone implant in the shape of a wedge is typically inserted between the two bone portions or into the joint. The wedge, however, has to be retained in its insertion position by a plate placed over the joint. The plate can cause irritation to the adjacent anatomy as well as to the patient.

It is therefore evident from the above that there is a need for a foot bone implant in the shape of a wedge that overcomes the deficiencies of the prior art.

The present invention is a wedge-shaped bone implant, system and method of use particularly, but not necessarily, for fixing bones of the foot. The wedge-shaped bone implant has bone screw bores that are each configured to hold a bone screw at a particular angle for receipt in a bone portion, thereby eliminating the need to also use a plate.

In one form, the wedge-shaped bone implant is moreover configured to receive a plate that aids in preventing a bone screw from backing out of its implant bore. The plate may be fastened to the wedge-shaped bone implant by one or more fastening screws. In this form, the top of the wedge-shaped implant has a recess that at least partially surrounds openings of the two implant bores. The recess is configured to receive the plate such that the plate at least partially obstructs the ability of a bone screw head within the implant bore to back out. Moreover, in this form, one or more of the threaded fastening screw bores for the fastening screws of the cover, may be used for engagement with an insertion instrument.

In another form, the wedge-shaped bone implant lacks a configuration on the top and thus does not accept a plate for covering the bone screws. In this case, a threaded bore may be provided for engagement with an insertion instrument instead of a threaded plate fastening screw bore.

One implant bore extends from the top of the implant body to one tapered side of the implant body, while the other implant bore extends from the top of the implant body to the other tapered side of the implant body. When installed, one bone screw projects from one tapered side of the shaped implant body, while the other bone screw extends from the other tapered side of the implant body. One bone screw thereby projects into one foot bone portion, while the other bone screw projects into the other bone screw portion, or different foot bones.

The bone implant can include an opening that extends through the implant body from one tapered side thereof to the other tapered side thereof. This opening allows the introduction and retention of bone graft material in order to promote bone fusion (i.e. a graft window). One tapered side of the body may also have teeth, serrations or the like that at least partially surround the graft window. The other tapered side may likewise also have teeth, serrations or the like that at least partially surround the graft window.

In one form, the implant body includes a through hole, bore, slot or the like in the distal aspect of the implant body. This allows for the insertion of a metallic component (e.g. titanium or tantalum) to allow for the visibility of the extent of the implant body in radiography, x-ray, or the like.

The present bone implant is thus characterized by an implant body in the general shape of a wedge, (e.g. as may be defined in solid geometry, as a right triangular prism with a rounded top, including a right oblique wedge in which the top edge is symmetrically shortened, causing the end triangles to slant obliquely) thus forming a right oblique wedge. The first bone screw bore extends from the rounded top to one slanted side of the wedge, while the second bone screw bore extends from the rounded top to the other slanted side of the wedge opposite the one side.

In one form, the outer configuration of the general wedge shape of the present foot bone implant may be modified from a traditional right oblique wedge shape to other wedge shapes or shapes incorporating a wedge structure. One such wedge modification provides a crescent or arced shaped wedge or a wedge in the shape of a crescent or arc. The crescent shaped wedge may include a threaded bore for engagement with an insertion instrument instead of a threaded plate fastening screw bore. The crescent shape also defines a bone graft opening or area that allows the introduction and retention of bone graft material in order to promote bone fusion. One tapered side of the implant body may also have teeth, serrations or the like that at least partially surround the graft opening. The other tapered side may likewise also have teeth, serrations or the like that at least partially surround the graft opening. The implant body may include a through hole, bore, slot or the like in the distal aspect of the implant body allowing for the insertion of a metallic component (e.g. titanium or tantalum) to allow for the visibility of the extent of the implant body in radiography, x-ray, or the like.

According to one method of use, the bone implant is placed into a bone joint to correct a deformity and provide fixation for fusion. The present bone implant permits the inclusion of bone screws to self-retain the wedge within the joint as well as providing stability for fusion. This is accomplished without the need for an additional plate.

According to another method of use, bone graft material is placed in the graft window, opening or area of the bone implant. The bone implant with bone graft material is then placed into a bone joint, bone osteotomy site, bone fracture or the like and provide fixation for fusion. The bone implant with bone graft material permits the inclusion of bone screws to self-retain the wedge within the joint as well as providing stability for fusion. Again, this is accomplished without the need for an additional plate.

Further aspects of the present invention will become apparent from consideration of the drawings and the following description of preferred forms of the invention. A person skilled in the art will realize that other forms of the invention are possible and that the details of the invention can be modified in a number of respects without departing from the inventive concept. The following drawings and description are to be regarded as illustrative in nature and not restrictive.

The features of the invention will be better understood by reference to the accompanying drawings which illustrate forms of the invention, wherein:

FIG. 1 is an isometric view of a wedge-shaped bone implant fashioned in accordance with the principles of the present invention;

FIG. 2 is an isometric view of the wedge-shaped bone implant of FIG. 1 having a bone screw situated in the bone implant and another bone screw ready for insertion into the bone implant;

FIG. 3 is an isometric view of the wedge-shaped bone implant of FIG. 1 having two bone screws situated therein along with a screw retention plate, forming a bone implant system;

FIG. 4 is an end view of the bone implant system of FIG. 3 ;

FIG. 5 is a top view of the bone implant system of FIG. 3 ;

FIG. 6 is an isometric view of the bone screw retention cover/plate of the bone implant system of FIG. 3 ;

FIG. 7 is an isometric view of another wedge-shaped bone implant fashioned in accordance with the principles of the present invention;

FIG. 8 is a side view of the bone implant of FIG. 7 ;

FIG. 9 is an isometric view of the bone implant of FIG. 8 having two bone screws situated therein;

FIG. 10 is a side view of the bone implant with bone screws of FIG. 9 ;

FIG. 11 is an isometric view of another wedge-shaped bone implant fashioned in accordance with the principles of the present invention;

FIG. 12 is an isometric view of the wedge-shaped bone implant of FIG. 11 having a bone screw situated in the bone implant and another bone screw ready for insertion into the bone implant;

FIG. 13 is an isometric view of the wedge-shaped bone implant of FIG. 11 having two bone screws situated therein, forming another foot bone implant system;

FIG. 14 is a top view of the bone implant system of FIG. 13 ;

FIG. 15 is an end view of the bone implant system of FIG. 13 ;

FIG. 16 is an isometric view of another wedge-shaped bone implant fashioned in accordance with the principles of the present invention;

FIG. 17 is an isometric view of the wedge-shaped bone implant of FIG. 16 having a bone screw situated in the bone implant;

FIG. 18 is a top view of the wedge-shaped bone implant of FIG. 16 having two bone screws situated in the bone implant;

FIG. 19 is an top end view of the wedge-shaped bone implant of FIG. 16 having two bone screws situated in the bone implant;

FIG. 20 is a side view of the wedge-shaped bone implant of FIG. 16 having two bone screws situated in the bone implant;

FIG. 21 is a bottom end view of the wedge-shaped bone implant of FIG. 16 having two bone screws situated in the bone implant; and

FIG. 22 is a view of bones of a left foot with the wedge-shaped bone implant of FIG. 16 implanted in a fracture or osteotomy cut of the first metatarsal of the foot.

Referring to FIGS. 1-6 and, in particular FIG. 1 , there is depicted a bone implant generally designated 10 . The bone implant 10 is fashioned from a known biocompatible implant material and is used for aiding or providing internal fixation of calcaneus, tarsal, and metatarsal bones of the foot in cases such as, but not limited to, filling an osteotomy or expanding and correcting an angular deformity in the foot. The bone implant 10 may be used with other bones of the body such as the hand. However, the bone implant 10 will be described within this detailed description of the invention for us with bones of the foot and thus as a foot bone implant 10 . The foot bone implant 10 has a generally wedge-shaped body 12 as wedges are defined in solid geometry and explained in the Summary of the Invention. As such, the body 12 has a generally rounded top 13 , a generally planar first side 14 , a generally planar second side 15 (see FIG. 4 ), a generally planar first end 16 , a generally planar second end 17 (see FIG. 4 ), and a generally pointed bottom 18 . The first and second sides 14 and 15 each slope inwardly from the top 13 to the bottom 18 . The dimensions and angles of the foot bone implant 10 may be changed as desired in order to accommodate varying anatomies, purpose, and desired outcome. It should also be appreciated that the foot bone implant 10 and/or its principles are applicable to other bones of the body such as, but not limited to, the bones of the hand.

The body 12 has two bores 20 , 21 each of which are dimensioned to receive a bone screw 90 such that the head of the bone screw is held by the body 12 and a portion of the tip and shank of the bone screw 90 extend from the body (see e.g., FIGS. 3-5 ) for receipt in a foot bone. The first bone screw bore 20 extends between the top 13 and the first side 14 such that the tip of a bone screw 90 extends from the first side 14 at an angle thereof. As particularly seen in FIG. 5 , the opening of the first bone screw bore 20 on the top 13 of the body 12 is situated proximate to and on the edge between the top 13 and the second side 15 creating the angled bone screw bore 20 . The second bone screw bore 21 extends between the top 13 and the second side 15 such that the tip of a bone screw 90 extends from the second side 15 at an angle thereof. As again particularly seen in FIG. 5 , the opening of the second bone screw bore 21 on the top 13 of the body 12 is situated proximate to and on the edge between the top 13 and the first side 14 creating the angled second bone screw bore 21 . Both bone screw bore openings on the top 13 of the body 12 are sized and configured to capture and retain the head of a bone screw. Moreover, both bone screw bore openings on the top 13 are configured such that the heads of the bone screws are countersunk relative to the surface of the top 13 .

A configured recess, channel, groove, depression, or the like 23 is provided in the surface of the top 13 . The recess 23 is in communication with the bone screw bore openings on the top 13 . Additionally, a threaded bore 24 is provided in the body 12 within the recess 23 of the top 13 , the threaded bore 24 configured to receive a threaded screw or fastener 92 . The recess 23 is further configured to receive a cover or plate 30 . As seen in FIG. 6 , the cover 30 , made from a biocompatible material, has hole 31 and first and second wings 32 , 33 . The cover 30 is shaped such that it fits into the recess 23 . Preferably, but not necessarily, the cover 30 is shaped in similar manner to the recess 23 . The cover 30 is received in the recess 23 such that the hole 31 is aligned with the threaded bore 24 in the top 13 of the body 12 , with the first wing 32 extending over at least a part of the opening of first bone screw bore 20 and the second wing 33 extending over at least a part of the opening of the second bone screw bore 21 . FIGS. 3 and 5 show the cover 30 mounted to the body 12 by the threaded screw 92 . Two bone screws 90 are also situated in the body 12 . The first wing 32 extends over or covers a portion of the bone screw head of the bone screw 90 that is in the first bone screw bore 20 . The second wing 33 extends over or covers a portion of the bone screw head of the bone screw 90 that is in the second bone screw bore 21 . The first and/or second wing may be shaped to extend over more of the bone screw head than shown. Because the wings are over the bone screw heads, this prevents the bone screw from backing out of the bone screw bore.

Referring to FIGS. 7-10 , there is depicted a foot bone implant, generally designated 10 a , being a variation of the foot bone implant 10 . As such, the foot bone implant 10 a is thus fashioned in a generally like manner to the foot bone implant 10 , with the like features and/or components denoted by the addition of the letter “a” to the feature and/or component of the foot bone implant 10 . Because these features and/or components are the same, they will not be discussed in detail. Reference should therefore be made to the foot bone implant 10 for details.

As best seen in FIGS. 7 and 9 , the foot bone implant body 12 a has an opening 60 that extends from the one tapered or slanted side 14 a to the other tapered or slanted side 15 a . While the opening 60 is shown as rectangular, it should be appreciated that the opening 60 may be configured as desired. The opening 60 is used to receive and hold bone graft material. As such, the opening 60 may be considered a bone graft window or simply a graft window. The bone graft material may be of any kind. Moreover, the graft window may comprise two or more openings that each extend from the one tapered or slanted side 14 a to the other tapered or slanted side 15 a . These graft openings can be shaped as desired.

As seen in FIGS. 9 and 10 , the two bone screws 90 are shown situated in the body 12 a such as they would appear when implanted. The bone screw cover 30 is within the top recess 23 a and fastened to the body 12 a via the fastener 92 . As per the foot bone implant 10 , portions of the cover 30 extend over the bone screw heads in order to prevent the bone screws from backing out.

In addition to the bone graft window 60 , the body 12 a has features for aiding in and/or promoting fusion between two foot bones or foot bone portions. These features also aid in keeping the body 12 a in place. Particularly, a portion of the one tapered or slanted side 14 a has teeth, serrations or the like 62 , while a portion of the other tapered or slanted side 15 a likewise has teeth, serrations or the like 64 . The teeth 62 surround the graft window 60 or at least are present about the top and sides of the graft window 60 in the slanted side 14 a . Likewise, the teeth 64 surround the graft window 60 or at least are present about the top and sides of the graft window 60 in the slanted side 15 a . The upper portions of the slanted sides 14 a and 15 a proximate the top 13 a and the lower portions of the slanted sides 14 a , 15 a proximate the bottom 18 a preferably, but not necessarily, lack teeth, serrations, or the like.

Referring to FIGS. 11-15 , there is depicted a foot bone implant, generally designated 10 b , being a variation of the foot bone implants 10 and/or 10 a . As such, the foot bone implant 10 b is thus fashioned in a generally like manner to the foot bone implants 10 , 10 a , with the like features and/or components denoted by the addition of the letter “b” to the feature and/or component of the foot bone implants 10 , 10 a . Because these features and/or components are the same, they will not be discussed in detail. Reference should therefore be made to the foot bone implants 10 , 10 a for details.

As best seen in FIGS. 11-13 , the foot bone implant body 12 b has an opening 60 b that extends from the one tapered or slanted side 14 b to the other tapered or slanted side 15 b . While the opening 60 b is shown as rectangular, it should be appreciated that the opening 60 b may be configured as desired. The opening 60 b is used to receive and hold bone graft material. As such, the opening 60 b may be considered a bone graft window or simply a graft window. The bone graft material may be of any kind. Moreover, the graft window may comprise two or more openings that each extend from the one tapered or slanted side 14 b to the other tapered or slanted side 15 b . These graft openings can be shaped as desired.

As seen in FIGS. 13-15 , the two bone screws 90 are shown situated in the body 12 b such as they would appear when implanted. In addition to the bone graft window 60 b , the body 12 b has features for aiding in and/or promoting fusion between two foot bones or foot bone portions. These features also aid in keeping the body 12 b in place. Particularly, at least a portion or more of the one tapered or slanted side 14 b has teeth, serrations or the like 62 b , while at least a portion or more of the other tapered or slanted side 15 b likewise has teeth, serrations or the like 64 b . The teeth 62 b surround the graft window 60 b or at least are present about the top and sides of the graft window 60 b in the slanted side 14 b . Likewise, the teeth 64 b surround the graft window 60 b or at least are present about the top and sides of the graft window 60 b in the slanted side 15 b . The upper portions of the slanted sides 14 b and 15 b proximate the top 13 b and the lower portions of the slanted sides 14 b , 15 b proximate the bottom 18 b preferably, but not necessarily, lack teeth, serrations, or the like. It should be appreciated that any pattern of teeth, direction of teeth, and/or dimensions of teeth may be used.

As best seen in FIGS. 11-14 , the top 13 b of the implant body 12 b lacks a configuration on the top for a cover and thus does not accept a plate for covering the bone screws like foot implants 10 and 10 a . In this case, a threaded bore 24 b may be provided for engagement with an insertion instrument (not shown) instead of a threaded plate fastening screw bore.

As best seen in FIGS. 11-12 , the implant body 12 b includes a through hole, bore, slot or the like 73 b in the distal aspect 18 b of the implant body 12 b . This allows for the insertion of a metallic component such as titanium or tantalum (not shown) to allow for the visibility of the extent of the implant body in radiography, x-ray, or the like.

Referring to FIGS. 16-21 , there is depicted another foot bone implant, generally designated 10 c , being a variation or modification from the traditional right oblique wedge shape foot bone implants 10 , 10 a , and 10 b . However, the foot bone implant 10 c is fashioned in a generally like manner to the foot bone implants 10 , 10 a , and 10 b , and thus like features and/or components are denoted by the addition of the letter “c” to the feature and/or component of the foot bone implants 10 , 10 a , 10 b . Because these features and/or components are at least generally the same, some will not necessarily be discussed in detail. Reference should therefore be made to the foot bone implants 10 , 10 a , and 10 b for details if necessary. The foot bone implant 10 c is fashioned from a known biocompatible implant material and is used for aiding or providing internal fixation of calcaneus, tarsal, and metatarsal bones of the foot in cases such as, but not limited to, filling an osteotomy or expanding and correcting an angular deformity in the foot. Other uses are contemplated.

The foot bone implant 10 c has a body 12 c generally in the form of a crescent or arced shaped wedge or a wedge in the shape of a crescent or arc. The crescent shaped wedge body 12 c has a generally curved top 13 c , a generally planar first side 14 c , a generally planar second side 15 c , a generally curved first end 16 c , a generally curved second end 17 c , and a curved bottom 18 c forming first and second legs 19 a , 19 b . The first and second sides 14 c and 15 c each slope, slant or incline inwardly from the curved top 13 c to the curved bottom 18 c . The body 12 c further includes a threaded bore 24 c for engagement with an insertion instrument (not shown) instead of a threaded plate fastening screw bore. The dimensions and angles of the foot bone implant 10 c may be changed as desired in order to accommodate varying anatomies, purpose, and desired outcome. It should also be appreciated that the foot bone implant 10 c and/or its principles are applicable to other bones of the body such as, but not limited to, bones of the hand.

The body 12 c has two bores 20 c , 21 c each of which are dimensioned to receive a bone screw 90 such that the head of the bone screw is held by the body 12 c and a portion of the tip and shank of the bone screw 90 extend from the body for receipt in a bone. The first bone screw bore 20 c extends between the curved top 13 c and the first side 14 c such that the tip of a bone screw 90 extends from the first side 14 c at an angle thereof. As particularly seen in FIG. 19 , the opening of the first bone screw bore 20 c on the curved top 13 c of the body 12 c is situated proximate to and between the curved top 13 c and the second side 15 c creating the angled bone screw bore 20 c . The second bone screw bore 21 c extends between the curved top 13 c and the second side 15 c such that the tip of a bone screw 90 extends from the second side 15 c at an angle thereof. As again particularly seen in FIG. 19 , the opening of the second bone screw bore 21 c on the curved top 13 c of the body 12 c is situated proximate to and between the curved top 13 c and the first side 14 c creating the angled second bone screw bore 21 c . Both bone screw bore openings on the curved top 13 c of the body 12 c are sized and configured to capture and retain the head of the bone screw 90 . Moreover, both bone screw bore openings 20 c , 21 c on the curved top 13 c are configured such that the heads of the bone screws 90 are countersunk relative to the surface of the curved top 13 c.

As best seen in FIGS. 16-18 , because the bone implant body 12 c is crescent shaped, the bottom 18 c between the first and second legs 19 a , 19 b defines an opening that may be used to receive and hold bone graft material. As such, the crescent shaped opening defined by the curved bottom 18 c may be considered a bone graft opening or area. Since the curved bottom 18 c faces into the bone when implanted (see FIG. 22 ), the bone graft material is held within the bone draft opening. The bone graft material may be of any kind.

As seen in FIGS. 18-21 , the two bone screws 90 are shown situated in the body 12 c such as they would appear when implanted. In addition to the bone graft opening defined between the first and second legs 19 a , 19 b of the curved bottom 18 c , the body 12 c has features for aiding in and/or promoting fusion between two bones or bone portions. These features also aid in keeping the body 12 c in place. Particularly, at least a portion or more of the slanted side 14 c has teeth, serrations or the like 62 c , while at least a portion or more of the other slanted side 15 c likewise has teeth, serrations or the like 64 c . The teeth 62 c surround the graft opening. Likewise, the teeth 64 c surround the graft opening. The upper portions of the slanted sides 14 c and 15 c proximate the curved top 13 c preferably, but not necessarily, lack teeth, serrations, or the like. It should be appreciated that any pattern of teeth, direction of teeth, and/or dimensions of teeth may be used.

While not shown in the figures, the implant body 12 c may include a through hole, bore, slot or the like in the distal aspect of the implant body 12 c . This allows for the insertion of a metallic component such as titanium or tantalum (not shown) to allow for the visibility of the extent of the implant body in radiography, x-ray, or the like.

Referring to FIG. 22 bones of a left human foot, generally designated 100 , are depicted. The first metatarsal 101 of the foot 100 has had a fracture or osteotomy cut 102 into which the bone implant 10 c (with or without bone graft material) has been implanted.

It should be appreciated that although the present bone fixation device has been shown in the figures and described above in particularity with respect to bones of the foot, such is applicable to bones of the hand; those bones being very similar in anatomy. It should also be appreciated that dimensions of the body and its features and/or components can be changed as desired.