HK1241680B - Implant for stabilizing fractured or non-fractured bones - Google Patents

Description

Implants for stabilizing broken or unbroken bones

Technical Field

The invention relates to a bone implant, a use of an implant and a method for stabilizing a fractured or non-fractured bone according to the independent claims.

Background Art

Bone implants are widely used to stabilize broken bones.

For example, US2009/0157078 discloses a cannulated screw for repairing defects in the humerus or femur. A portion of the screw is unthreaded but contains a hole through which cement can be introduced into the bone through a gap. The device includes a screw head on one side of the implant, which requires the screw to partially extend outside the bone. The other end of the implant is threaded, so the screw is only secured when the threads can be fixed in the bone on the side opposite the screw head. This would limit the application of such an implant.

WO2012/142032 discloses a method and device for bone preparation. The device includes an insert with perforations through which a fluid can be introduced into the bone. The device can be used to fix bone fragments internally or to pack into potentially weak and/or cancerous bones. The fluid can be bone cement. The implant portion of this device is fixed outside the bone, making it very complex. Furthermore, using multiple implants in a single bone weakens the bone tissue due to the number of introduction channels.

WO2012/066236 relates to a device combining two interdigitated implants for the prophylactic or therapeutic treatment of femoral fractures. The interdigitated implants are fixed to each other to prevent any movement of the implants. This device can only be used in bones that allow the interdigitated implants to be placed.

Summary of the Invention

The object of the present invention is therefore to avoid the disadvantages of the prior art and to create a bone implant, a use of a bone implant and a method for stabilizing a fractured or non-fractured bone, which implant can be universally used for different bones of the human body and allows a stable positioning within the bone.

The object is achieved by a bone implant for stabilizing a broken bone or a non-broken bone, the bone implant comprising an implant body that is preferably cylindrical. The implant body extends from the front side to the end side along a longitudinal axis. The implant body has an implant width extending perpendicular to the longitudinal axis, wherein the length of the implant body along the longitudinal axis is at least five times the implant width. The implant body has an outer surface that is at least divided into a first surface and a second surface, wherein the first surface consists of an anchoring region that is at least partially distributed over the outer surface, preferably extending to a maximum of half the outer surface.

The anchoring region according to the present invention comprises a surface that improves the fixation of the implant when implanted in the bone. Bone tissue can more easily grow into the implant and improve the implant's anchoring in the bone. Such an implant is easily introduced and fixed in the bone, particularly the vertebrae. When the implant is implanted in the bone, the anchoring region is preferably located at the proximal end of the implant.

The implant body preferably has constant implant width throughout the first surface and the second surface at least. In addition, the implant is not included in the widening portion such as the screw head at the proximal end. Therefore, the implant width is preferably constant at least in the first and second surface ranges, and the implant width can be less in other regions.

The first surface and the second surface each preferably extend along the longitudinal axis and extend 360° around the longitudinal axis.

The implant can comprise an inner bore extending along the longitudinal axis or parallel to the longitudinal axis and having at least one, preferably two, openings on the front side and/or the end side.

An inner hole in the bone implant results in a lighter implant and in the case of two openings fluid can be introduced into the bone.

The length of the bone implant may be in the range of 10 mm to 250 mm.

Specific bone implants can be used for different bones and still have the required length for stabilizing the corresponding bone.

Bone width can range from 5 mm (rib) to 50 mm (femoral shaft) or 80 mm (humeral head). Bone implant width can range from 2 mm to 10 mm.

Such bone implants can be easily introduced into the bone without damaging other bone tissue and still provide sufficient stability for bone stabilization purposes.

The outer surface, preferably the second surface, can have a hole with a wall surrounding the hole axis.

The bone implant having holes on the outer surface or the second surface respectively, on the one hand, allows bone tissue to grow into the holes, thereby improving the implant position, and, in the case of bone implants having holes, allows fluid to be introduced into the bone tissue around the implant in which the inner hole is located.

The fluid is preferably a bone cement such as polymethylmethacrylate (PMMA) bone cement, a bioresorbable bone cement or any other product that allows the implant to be fixed in the bone.

The holes may have a diameter of 0.2 mm to 5 mm on the outer surface or the second surface, respectively.

Through such pores, bone tissue can grow rapidly and fluids (such as bone cement) can be easily introduced into the bone.

The hole walls may be cylindrical, preferably conical.

The cylindrical hole is easy to manufacture, thereby reducing manufacturing costs, while the conical shape optimizes the distribution of the fluid introduced into the bone through the bone implant.

The implant may comprise a first set of holes, wherein hole axes of the first set of holes are arranged substantially perpendicular to the longitudinal axis.

A set of holes may include one or more holes.

A hole having a hole axis arranged perpendicular to the longitudinal axis will result in the distribution of fluid through the hole radially away from the implant, thus allowing the bone cement to reach as far as possible.

The implant may comprise a second set of holes, wherein the hole axes of the second set of holes are inclined relative to the longitudinal axis, preferably at an angle greater than 90° but less than 150° relative to the longitudinal axis.

The angled bore axis enables the fluid to be distributed to specific points within the bone as the implant is seated in the bone.

The implant may comprise a third set of holes, wherein the hole axes of the third set of holes are inclined at a different angle to the longitudinal axis than the holes of the second set of holes, preferably at an angle less than 90° but greater than 30° to the longitudinal axis.

The tilted hole axis can distribute the intraosseous fluid to a specific area when the implant is already located in the bone. In addition, the tilted hole can even introduce bone cement into nerve-sensitive areas because it is possible to guide the bone cement flow into a specific area.

In particular, the combination of the first, second, and third sets of holes enables fluid to be directed from within the implant to a specific bone region relative to the implant.

The holes may be substantially evenly distributed over a 360° area around the longitudinal axis of the outer or second surface, and are preferably arranged in rows along the longitudinal axis such that the distance between adjacent holes in a row is substantially the same.

This arrangement allows for optimal distribution of fluid and uniform distribution of tissue growing into the implant.

The holes may be located in a region of 180° to 270° about the longitudinal axis of the outer or second surface and are preferably arranged in rows along the longitudinal axis such that the distance between adjacent holes and a row is substantially the same.

The arrangement of the holes in the region of 180° to 270° around the longitudinal axis makes it possible to guide the fluid through the implant only to the parts of the bone that require it.

The first holes of a first column and the first holes of an adjacent second column may have different distances from the front side, preferably the difference in distance being equal to half the distance between two adjacent holes in a column.

This distribution of adjacent holes in adjacent rows results in an optimized distribution of the fluid introduced into the bone through the implant.

The distribution of the holes is preferably chosen so that the stability of the implant is not or not significantly compromised and that the fluid distribution is still optimal for the particular environment. In the spine, the holes will be located in the distal portion of the implant that is implanted in the vertebral body and will be arranged so that the bone cement can be injected at 270° to 300° around the longitudinal axis, rather than on one side of the upper end plate to avoid leakage if the end plate breaks.

In humeral applications, the holes are all located 360° around the longitudinal axis of the implant to allow 360° bone cement flow. This allows for good implant fixation, bone reinforcement, and adequate tumor filling (if applicable).

The anchoring region may comprise means for improving the fixation of the implant in the bone, which are preferably surface structures and/or roughness and/or recesses.

The surface structure may be a groove, a thread or an annular structure, and the pitch of the thread or groove or the annular structure may be square, symmetrical triangular or asymmetrical triangular. Alternatively or additionally, the surface structure may include recesses that are straight, spiral or have a cross or diamond pitch. The recesses in the anchoring area may be 0.5 mm to 3 mm deep.

All depth values of the present invention are measured from top to bottom. Of course, there can be statistical variations.

The surface structure improves the anchoring of the implant.

The roughness can vary from 1 micron to 0.5 mm.

The anchoring region may comprise a surface structure in the form of grooves, preferably 6 or 8 grooves, which are distributed substantially equally around the longitudinal axis and extend coaxially along the longitudinal axis.

The grooves may have the same shape and/or height as the recesses, and the surface structure may be threaded or annular.

The use of a surface structure in the form of grooves improves the anchoring of the implant, thus resulting in a more durable and safer implant.

The anchoring region can comprise a surface structure in the form of a thread or an annular groove. Such an anchoring region improves the fixation of the implant in the bone.

The cross section of groove can be U-shaped, V-shaped or square.Through groove, the surface contact between bone and implant increases, and the stress concentration on bone is limited.It also allows the rotational stability of implant before bone cement injection, which is important for spinal implants where injection holes must be oriented, for example.After bone cement injection, implant stability is reached by bone cement, for example the stability of implant against rotation and translation.

The implant may comprise a fixation connector which allows the implant to be retained when introduced into the bone.

The fixing connector can be, for example, a thread, by which the bone implant is connected to the tool. The fixing connector is preferably a thread on the inside of the bone implant's inner hole, and the internal thread preferably has a larger diameter than the rest of the hole to make it easier to introduce the tool. By means of such an internal thread, the outer surface can be optimized for fixing the implant in the bone.

Furthermore, when connected via the fixed connector, fluid can be introduced through the tool and the implant. This results in easy handling of the implant when introducing and fixing the implant.

The outer surface may comprise a third surface having an at least partially conical shape.Such a third surface is arranged opposite the anchoring surface and results in the possibility of easier introduction of the bone implant into the bone.

The implant may be made of any implantable material, such as polyetheretherketone (PEEK), titanium, stainless steel, or Nitinol, or a combination thereof.

This object is further achieved by using an implant for restoring a broken bone as described above.

This object is further achieved by using an implant for preventing bone fractures as described above.

The fractured bone can be, for example, the humeral head or shaft, calcaneus, carpal radius, tibia, pelvis or rib. Examples of applications for preventing fractures are, for example, the humerus or ribs or vertebral bodies in the case of severe osteoporosis or tumor-induced osteolytic lesions.

This object is further achieved by a method for stabilizing a fractured or non-fractured bone by inserting a bone implant into a bone as described above and preferably introducing bone cement into the bone via the bone implant.

This approach results in an easy introduction and fixation of the bone implant within the bone without the need for any plates or additional fixation mechanisms.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention is described below by way of example with reference to the accompanying drawings, in which:

FIG1 : A bone implant according to a first embodiment,

FIG2 : A first section of a bone implant in a second embodiment,

FIG3 : A cross section through a bone implant in a third embodiment,

FIG4 : A bone implant according to a fourth embodiment,

FIG5 : Cross section of the bone implant according to FIG4 ,

FIG6 : A fifth embodiment of a bone implant,

Figures 6a to 6c: Details of Figure 6,

FIG7 : Cross-section of a bone implant of a sixth embodiment,

Figure 8: Two bone implants stabilizing a vertebral fracture.

FIG9 : Two implants for stabilizing vertebral fractures according to a third embodiment,

FIG. 10 : A bone implant for stabilizing a humerus according to a first embodiment.

DETAILED DESCRIPTION

FIG1 shows a bone implant 1 according to a first embodiment. The bone implant 1 includes an implant body 2 having a longitudinal axis 3. The implant body 2 includes a front side 4 and a front side 5. Furthermore, the implant body 2 is divided into a first surface 7 and a second surface 8. The first surface 7 includes an anchoring region 9 for improving the anchoring of the implant in the bone. Perpendicular to the longitudinal axis, the implant body 2 includes an implant width 6. The implant width 6 is constant along the first and second surfaces 7, 8 and is not exceeded at any other point in the implant 1. The second surface 8 includes a hole 12 and an inner hole 10 within the implant body 2. The hole 12 enables the introduction of a fluid, such as bone cement, into the bone through the implant 1, thereby optimizing the fixation of the implant 1 within the bone as bone tissue grows into the hole 12. The implant body 2 also includes a conical third surface 17. The implant width is reduced in the third surface, making it easier to introduce the implant 1 into the bone. The front side 4 of the implant body 2 is rounded, forming a hemisphere that facilitates the introduction of the implant 1 into the bone. The anchoring region 9 of the first surface 7 includes a surface structure for improving the anchoring of the implant 1 within the bone. The holes are distributed 360 degrees around the circumference of the implant body 2, with the holes 12 arranged in multiple rows. The rows are offset so that the first holes 12 of a first row 18 are at a different distance from the front side 4 than the first holes 12 of an adjacent second row (not shown). The implant body is 100 mm long, while the implant width is 5 mm. The diameter of the holes 12 is 2.5 mm. The walls of the holes 12 are cylindrical.

For example, the values for standard spinal implants are: length 50 to 85 mm, preferably 70 mm on average, diameter 4 to 7 mm, preferably 5 mm, and bore 1 to 3 mm, preferably 2 to 2.5 mm.

Fig. 2 shows the cross section of the second embodiment of the present invention. In this embodiment, the implant body 2 comprises an endoporus 10 along the longitudinal axis. At the end side 5, a fixed connector is arranged to enable the implant body 2 to be connected to an insertion tool (not shown). Contrary to the first embodiment in Fig. 1, the hole 12 in the second embodiment is arranged on the second surface 8 that is larger than the smaller first surface 7. The first group of holes 12 comprises a hole axis 11a, which is arranged perpendicular to the longitudinal axis 3. The second group of holes comprises an inclined axis 11b, and the hole axis 11b is 120 ° relative to the inclination of the longitudinal axis 3. The front side 4 also comprises a third surface 17 to help the implant being introduced into the bone.

Figure 3 shows a cross-section of a third embodiment of the present invention. In this embodiment, the inner bore 10 includes a threaded fixing connector 16 on the end 5 of the implant body 2. This thread allows tools to be secured within the implant. The bores 12 are arranged 270° around the longitudinal axis 13, so that fluids, such as bone cement, are only guided 260° from the implant. This prevents sensitive areas from filling with fluid or specific bone cement.

FIG4 shows a fourth embodiment of the present invention. This embodiment corresponds to the first embodiment in FIG1 , except that the first surface 7 includes an anchoring region 9. The anchoring region 9 includes threads, wherein the thread pitch extends from the implant width 6 . This anchoring region 9 improves the fixation of the implant within the bone. Furthermore, the third surface 17 in this embodiment is shorter than in the embodiment in FIG1 , and therefore the conical shape of the third surface 17 has a steeper inclination than in the embodiment in FIG1 . Furthermore, the front side 4 is more pointed than in the embodiment in FIG1 .

Figure 2 shows the embodiment disclosed in Figure 3, but the first surface 7 comprises a threaded anchoring area 9. The anchoring area 9 in this embodiment corresponds to the anchoring area 9 shown in Figure 4.

Fig. 6 illustrates the embodiment of implant 1, and it comprises the first surface 7 with longitudinal groove 13.Longitudinal groove 13 has improved the anchoring of bone implant in bone.Longitudinal groove can comprise square cross-sectional shape so that it avoids rotation (Fig. 6 a), hemispherical cross-sectional shape so that insertion is easier and with square or angled compared to make bone contact better (Fig. 6 b) or triangular cross-sectional shape so that surface contact maximizes (Fig. 6 c).Only distribute from 270 ° to 300 ° around the circumference of implant 1 according to the hole 12 in the embodiment of Fig. 6.

Fig. 7 shows the cross section of the embodiment according to Fig. 6. The inner hole 10 along the longitudinal axis 3 includes a fixing connector 16, which can be screwed to a tool (not shown). The hole 12 is arranged along three different hole axes 11a-11c. The first hole axis 11a is arranged perpendicular to the longitudinal axis. The hole axis 11b for the second group of holes is arranged at 130 ° relative to the longitudinal axis 3. The hole axis 11c for the third group of holes is arranged at 60 ° relative to the longitudinal axis. Since the bone cement introduced through the inner hole 10 and the hole 12 is optimally distributed in the vertebra, this hole arrangement is particularly suitable for vertebral implants. The purpose is to avoid the risk of leakage through the vertebral body wall that may have been damaged by fracture or the posterior side.

Figures 8a to 8c show an embodiment of an implant applied to a vertebra. Figure 8a shows a top view of the vertebra, Figure 8b shows a side view of the vertebra, and Figure 8c shows a back view of the vertebra, wherein two implants are introduced to stabilize the vertebra. The implant introduced in this embodiment is the implant according to Figure 1.

9a to 9c show the same views as FIG. 8 , with the embodiment of the implant according to FIG. 4 .

FIG10 shows an implant 1 used as a stabilizing implant in the humerus. The humerus is not fractured. However, the implant 1 is still introduced into the bone to stabilize it. The arrows show the route of introduction of the implant 1 into the humerus.

Claims (8)

1. A bone implant (1) for stabilizing fractured or unfractured bone, the implant comprising an implant body (2) extending along a longitudinal axis (3) from a front side (4) to an end side (5) and having an implant width (6) extending perpendicular to the longitudinal axis (3), wherein the length of the implant body (2) along the longitudinal axis (3) is at least 5 times the implant width (6), wherein the implant body (2) has an outer surface at least divided into a first surface (7) and a second surface (8), wherein the first surface (7) comprises an anchoring region (9) at least partially covering half of the outer surface and the second surface (8). The second surface (8) includes holes (12) having walls surrounding a hole axis (11), characterized in that the implant does not include a proximal widening portion, and the holes (12) are substantially evenly distributed in a 360° region surrounding the longitudinal axis (3) of the outer surface or the second surface (8) and are arranged in rows along the longitudinal axis (3) such that the distance between adjacent holes (12) in a row is substantially the same, the anchoring region (9) includes a mechanism for improving the fixation of the implant within the bone, wherein the mechanism is roughness, wherein the roughness is in the range of 1 micrometer to 0.5 millimeters in depth, and wherein the implant is made of PEEK. 2. The bone implant (1) according to claim 1, characterized in that the implant (1) includes an internal hole (10) extending along or parallel to the longitudinal axis (3) and having at least one opening on the anterior and/or posterior side. 3. The bone implant (1) according to any one of the preceding claims, characterized in that the length of the bone implant is in the range of 10 mm to 250 mm. 4. The bone implant (1) according to claim 1 or 2, characterized in that the width (6) of the bone implant is in the range of 2 mm to 10 mm. 5. The bone implant (1) according to claim 1, characterized in that the implant (1) includes a first set of holes (12), wherein the hole axis (11a) of the first set of holes (12) is substantially perpendicular to the longitudinal axis. 6. The bone implant (1) according to claim 5, characterized in that the implant includes a second set of holes (12), wherein the hole axis (11b) of the second set of holes (12) is inclined relative to the longitudinal axis (3). 7. The bone implant (1) according to claim 1 or 2, characterized in that the anchoring region (9) includes a surface structure in the form of a groove (13) which is substantially evenly distributed around the longitudinal axis and extends coaxially along the longitudinal axis. 8. The bone implant (1) according to claim 1 or 2, characterized in that the anchoring region (9) comprises a surface structure in the form of a thread (14) or an annular groove (15).