Manufacturing method for artificial joint stem

Abstract

To reduce a possibility of peeling of a coating film.SOLUTION: An manufacturing method of an artificial joint stem includes: a roughening step of forming a rough surface on a surface of a substrate; and a membrane forming step of forming a membrane containing a calcium phosphate material and an antibacterial material on at least a part of the surface of the substrate. The membrane forming step includes: forming, out of the surface of the substrate, only a part of an area where the rough surface is formed and at least a part of an area where the coating film is formed, such that both areas overlap each other.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a method for manufacturing a stem for an artificial joint.

Background Art

[0002] The use of biocompatible implants for the treatment of both bone injuries and diseases has been constantly expanding along with the increasing active and elderly populations. Among them, coated biocompatible implants are known from the viewpoints of antibacterial properties and bone fixation.

[0003] For example, Patent Document 1 describes a coating for a medical implant that contains a bone binder in part and an antibacterial metal agent containing silver.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Reduce the risk of the coating peeling off.

Means for Solving the Problems

[0006] The method for manufacturing a stem for an artificial joint according to the present disclosure includes a roughening step of forming a rough surface on the surface of a substrate, and a film forming step of forming a film containing a calcium phosphate-based material and an antibacterial material on at least a part of the surface of the substrate. In the film forming step, the film is formed such that only a part of the region where the rough surface is formed and at least a part of the region where the film is formed overlap on the surface of the substrate.

Effects of the Invention

[0007] According to one aspect of the present disclosure, the risk of the coating peeling off can be reduced.

Brief Description of the Drawings

[0008]

Figure 1

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Figure 20

Mode for Carrying Out the Invention

[0009] Hereinafter, an embodiment will be described in detail. Unless otherwise specified in this specification, "A~B" representing a numerical range means "A or more and B or less".

[0010] 〔1. Stem for artificial joint〕 First, with reference to FIGS. 1 to 6, the configurations of a stem 100 for an artificial joint and a stem 101 for an artificial joint according to an embodiment will be described. The stem 100 for an artificial joint and the stem 101 for an artificial joint are examples of the stem for an artificial joint according to this embodiment. In the stem 100 for an artificial joint and the stem 101 for an artificial joint, the rough surface on the outer surface of the stem for an artificial joint and the region of the coating arranged on the surface are different. FIG. 1 is a schematic diagram showing the stem 100 for an artificial joint, and FIG. 2 is a diagram showing a state in which the coating 20 is removed from the stem 100 for an artificial joint and the rough surface 21 can be seen. As shown in FIG. 1, the stem 100 for an artificial joint includes a base 10 and a coating 20 located on the base 10. The coating 20 contains a calcium phosphate-based material and an antibacterial material. The calcium phosphate-based material has the effect of improving the fixation to bone. In addition, the antibacterial material has the effect of reducing the adhesion and growth of bacteria.

[0011] Further, the surface of the coating 20 has at least one recess 2X such as holes 200 and grooves 220. And, among the surfaces of the coating 20, the region 20X where the recess 2X is arranged is smaller than the other region 20Y. Further, the recess 2X has a plurality of holes 200 arranged non-continuously with each other. And at least one of the holes 200 has a planar shape with a bottom surface having a polygonal shape.

[0012] In addition, a coating 20 is disposed on the rough surface 21 shown in FIG. 2, and a part of the rough surface 21 is not covered by the coating 20 and is exposed. That is, the rough surface 21 has an exposed region 211 that is exposed from the coating 20. By the coating 20 being located on the rough surface 21, peeling of the coating 20 can be reduced.

[0013] In addition, the surface roughness of the exposed region 211 is greater than the surface roughness of the coating 20.

[0014] Also, as shown in FIG. 2, the exposed region 211 is smaller than the region where the coating of the rough surface 21 is disposed. When the upward direction is the proximal direction in the human body when the artificial joint stem 100 is used, the exposed region 211 is located only on the lower end side of the coating 20. And the edge of the lower end portion of the coating 20 is along the edge of the lower end portion of the rough surface 21.

[0015] In addition, there are a plurality of grooves 220, and at least one of the grooves (first groove) 220 has one tip located in the exposed region 211. Also, at least one of the other grooves (second groove) has both ends located on the coating 20.

[0016] Next, with reference to FIG. 5, the details of the hole 200 will be described. FIG. 5 is a schematic diagram showing a cross section of the hole 200.

[0017] Also, as shown in FIG. 5, the hole 200 increases in depth along one direction. In the example shown in FIG. 5, one depth of the hole 200 is DA and the other depth is DB, and DA < DB.

[0018] FIG. 3 is a schematic diagram showing an artificial joint stem 101, and FIG. 3 is a view showing a state in which the coating 20A is removed from the artificial joint stem 101 and the rough surface 21A can be seen. The artificial joint stem 101 shown in FIG. 3 also includes a base body 10 and a coating 20A located on the base body 10, similar to the artificial joint stem 100 shown in FIG. 1. The coating 20A contains a calcium phosphate-based material and an antibacterial material.

[0019] The shape of the stem 101 for artificial joints is different from that of the stem 100 for artificial joints and the coating 20 and the rough surface 21. As shown in FIG. 3, the length of the coating 20A in the stem 101 for artificial joints varies depending on the position in the vertical direction.

[0020] And, as shown in FIGS. 3 and 4, the edge of the coating 20A is non-parallel to the edge of the rough surface 21A.

[0021] FIG. 6 is a diagram showing an enlarged view of the surface layer of the A-A' cross section in FIG. 3. The substrate 10 includes a region 10A corresponding to the rough surface 21A and other regions 10B, and the coating 20A is formed so as to straddle the region 10A and the region 10B. That is, the coating 20A is arranged so as to cover both of the two types of adjacent surfaces at the boundary portion between the two types of surfaces. And, the region of the region 10B that is not covered by the coating 20A is exposed from the coating 20A.

[0022] As described above, the coating 20A has a coating region 10C that is located across the region 10A and the region 10B, which is an outer surface different from the region 10A. And, this coating region 10C is located on the lower end side of the substrate 10. Also, the surface roughness of the outer surface where the coating region 10C is located is larger than the surface roughness of the region 10B exposed from the coating region 10C.

[0023] In the stem 100 for artificial joints and the stem 101 for artificial joints, examples of the index of surface roughness include the arithmetic mean roughness Sa (ISO 25178). The surface roughness (Sa) of the coating 20 (20A) may be set, for example, to 10 to 80 μm, or may be set to 20 to 80 μm, or may be set to 30 to 70 μm. Also, the surface roughness (Sa) of the substrate 10 may be set to less than 1.0 μm, for example.

[0024] Note that the surface roughness Sa can be obtained from the measurement results of the entire region (for example, the region corresponding to the rough surface 21 or the rough surface 21A). The surface roughness of the coating 20 (20A) or the surface roughness of the substrate 10 may be measured, for example, in a stylus type or an optical type. Also, the surface roughness may be measured, for example, in accordance with "ISO 25178". Note that the measurement of the surface roughness is not limited to the above methods.

[0025] Here, conventionally, there has been room for improvement in the artificial joint stem from the viewpoint of achieving both antibacterial properties and control of the fixation to bone. That is, for example, when all of the surface of the artificial joint stem is covered with a coating containing a bone binder and an antibacterial metal agent, it has been difficult to control the fixation between the artificial joint stem and the bone. In this case, when removal of the artificial joint stem is required after surgery, there is a possibility that the removal becomes difficult. For example, there is a risk that the portion of the artificial joint stem 100 (101) embedded in the bone adheres excessively to the bone through the coating.

[0026] In the case of the artificial joint stem 101 according to the present disclosure, it has a coating 20A that straddles the region 10A and the region 10B, and the surface roughness of the coating 20A in the region 10A is larger than that in the region 10B. Therefore, sufficient fixation to bone and antibacterial properties can be ensured. On the other hand, the region 10B is exposed from the coating 20A and has a surface roughness smaller than that in the region 10A. Thus, excessive fixation to bone can be reduced. From the above, according to the artificial joint stem 101, it is possible to achieve both antibacterial properties and control of the fixation to bone.

[0027] For the substrate 10, metal, ceramics or plastic can be used. Examples of the metal include stainless alloys, cobalt-chromium alloys, titanium and titanium alloys. As the titanium alloy, an alloy obtained by adding at least one of aluminum, tin, zirconium, molybdenum, nickel, palladium, tantalum, niobium, vanadium and platinum to titanium can be used. Examples of the ceramics include alumina, zirconia and alumina-zirconia composite ceramics. Examples of the plastic include polyethylene, fluororesin, epoxy resin, polyetheretherketone (PEEK) resin and bakelite. In this embodiment, the substrate 10 is formed of a titanium alloy.

[0028] The shape of the substrate 10 may be, for example, substantially rod-shaped, but can be appropriately changed according to the shape of the artificial joint to be applied.

[0029] The artificial joint stem 101 may further include a layered member 30. The layered member 30 can be disposed on the region 10A. Thereby, as shown in FIG. 6, the region 10A becomes higher than the region where the layered member 30 is not provided. Therefore, when the artificial joint stem 101 is implanted into the bone, the region 10A can be mainly brought into contact with the bone. In this specification, the "layered member" means a member different from the coating 20 laminated on the substrate 10. For example, the surface of the layered member 30 may be made rough. Thereby, the region mainly in contact with the bone can be made rough. The layered member 30 may be formed by a spraying method as described later. Or the layered member 30 may be formed as a porous structure.

[0030] Note that the height of the layered member 30 may be set, for example, to have a lower limit of 100 μm or more, and may be set to 300 μm or more. Also, the upper limit may be set, for example, to 1000 μm or less, and may be set to 700 μm or less. Also, the surface roughness of the layered member 30 may be set to, for example, 10 to 80 μm, or may be set to 20 to 80 μm, or may be set to 30 to 70 μm.

[0031] Thus, the thickness of the layered member 30 is larger than the thickness of the coating 20A.

[0032] Note that, without providing the layered member 30, the base body 10 may be shaped such that mainly the region 10A contacts the bone. For example, the region 10A may be shaped to bulge with respect to the region 10B.

[0033] As the material of the layered member 30, the materials exemplified as the material of the base body 10 can be used. For example, the layered member 30 may be made of metal. The material of the layered member 30 and the material of the base body 10 may be the same material or different materials. Thereby, sufficient strength can be ensured. Note that, in the present embodiment, the layered member 30 is formed of a titanium alloy.

[0034] The layered member 30 may have an edge with a lower height as compared with the inside of the layered member 30. In the present specification, the "inside of the layered member" means the inside in the plane direction of the layered member 30. Thereby, the concentration of stress on the edge of the layered member 30 can be reduced.

[0035] The coating 20 contains a calcium phosphate-based material and an antibacterial material. As the calcium phosphate-based material, for example, one or more mixtures selected from the group consisting of hydroxyapatite, α-tricalcium phosphate, β-tricalcium phosphate, tetracalcium phosphate, octacalcium phosphate, and calcium phosphate-based glass can be used. As the antibacterial material, natural antibacterial agents, organic antibacterial agents, and inorganic antibacterial agents can be used. As the natural antibacterial agent, for example, hinokitiol can be used. As the organic antibacterial agent, for example, benzalkonium chloride can be used. As the inorganic antibacterial agent, a metal can be used, and as the metal, for example, silver, copper, zinc, etc. can be used. In addition to the calcium phosphate-based material and the antibacterial material, the coating 20 may contain glass ceramics and may contain antibacterial drugs such as penicillin and vancomycin.

[0036] The concentration of the antibacterial material in the coating 20 may be, for example, 0.05 wt% to 3.00 wt%, 0.05 wt% to 2.50 wt%, 0.05 wt% to 1.00 wt%, or 0.1 wt% to 1.00 wt%. If the concentration of the antibacterial material is 0.05 wt% or more, sufficient antibacterial properties can be obtained. Also, if the concentration of the antibacterial material is 3.00 wt% or less, the burden on the living tissue can be reduced.

[0037] A concentration gradient of the antibacterial material may exist in the coating 20. For example, the concentration of the antibacterial material contained in the upper end portion of the coating 20 may be greater than the concentration of the antibacterial material contained in the lower end portion of the coating. Thereby, the intrusion of bacteria from the upper end portion side of the coating 20 can be more effectively reduced. The antibacterial material may be contained only in the upper end portion of the coating 20.

[0038] On the substrate 10, a boundary line defined by the presence or absence of the coating 20 may exist. The length of the boundary line that encircles the substrate 10 may be greater than the circumferential length of a part of the substrate 10 located above and below the boundary line. For example, the portion where the boundary line exists may bulge in a nodular shape on the substrate 10.

[0039] The coating 20 may be disposed on the layered member 30. As described above, the layered member 30 can mainly come into contact with bone. The presence of the coating 20 on the layered member 30 can further improve the adhesion to bone and antibacterial properties.

[0040] The height of the layered member 30 may be greater than the thickness of the coating 20. Thereby, the region where the layered member 30 is formed becomes higher than the region where only the coating 20 is formed, so that the region where the layered member 30 is formed can be mainly brought into contact with bone. The thickness of the coating 20 may be set to be less than 100 μm, for example, and may also be set to be less than 50 μm. Also, the thickness of the coating 20 may be set to be 5 μm or more, for example.

[0041] Region 10B is exposed from the coating 20A. The discrimination between the portion where the coating 20A is disposed and the portion exposed from the coating 20A can be made by elemental analysis of the surface of each region. The method of elemental analysis can be carried out, for example, by mapping the surface elements with an energy dispersive X-ray analysis (EDX) device which is an accessory device of a general scanning electron microscope (SEM). Also, surface analysis methods such as X-ray photoelectron spectroscopy, Auger electron spectroscopy, secondary ion mass spectrometry, etc. may be used. Further, a sample obtained by mechanically scraping off the surface of each region may be chemically analyzed to confirm the elements. For example, on the surface of region 10A where the coating 20A is disposed, phosphorus, calcium, an antibacterial component, etc. are detected. On the surface of region 10B, the elements constituting the substrate 10 are detected, and phosphorus, calcium, an antibacterial component, etc. are not detected or are at or below the noise level.

[0042] Further, the substrate 10 as described above may include a main body portion and a neck portion connected to the upper end portion of the main body portion. The main body portion can be implanted in the femoral bone portion. The neck portion is exposed from the femur, provided with a head, and can be installed in an acetabular cup that pairs with the artificial joint stem.

[0043] The main body portion has a lower portion having a central axis extending along the vertical direction, and an upper portion having a shape including a curved portion that is continuous with the lower portion and extends in the vertical direction and curves such that the center moves away from the central axis as it goes upward. It can also be said that the upper side in the vertical direction regarding the substrate 10 corresponds to the proximal side in the human body, and the lower side corresponds to the distal side in the human body. Further, the upper portion has an upper end surface disposed offset from the central axis, and the neck portion is connected to the upper end surface. The neck portion is narrower than the main body portion (upper end surface). In other words, the neck portion can also be said to be a convex portion protruding in an oblique direction inclined from the central axis from the main body portion.

[0044] Further, the substrate 10 may further have a collar provided at the connection portion between the main body portion and the neck portion. The collar is a protruding portion protruding from the connection portion toward the surface direction of the upper end surface. The collar can reduce the main body portion from entering too far into the femur during the operation of the artificial joint stem.

[0045] The artificial joint stem 102 shown in FIG. 9 is also included in the artificial joint stem according to the present disclosure. For example, a recess 25 having an opening that opens on the surface of the coating 20 may be provided. The opening area of the recess 25 located on the upper end side of the coating 20 may be larger than the opening area of the recess 25 located on the lower end side of the coating 20. The recess 25 may be provided only at the upper end of the coating 20.

[0046] The artificial joint stem 103 shown in FIG. 10 is also included in the artificial joint stem according to the present disclosure. For example, the base body 10 may have a groove, and the groove may be arranged across the region where the coating 20 is arranged and the region exposed from the coating 20. The groove may extend to the upper end of the coating 20. The surface roughness in the groove located on the rough surface may be smaller than the surface roughness of the base body 10 located on the rough surface.

[0047] The base body 10 may have an inner portion 13 that curves in a concave shape and an outer portion 14 that curves in a convex shape. Here, the groove extends in the vertical direction, and the upper end of the groove may be located at the curved portion. Also, in the contraction portion 40'b, it may bend at either the inner portion 13 or the outer portion 14. For example, the groove may bend at the inner portion 13 in the contraction portion 40'b. Also, the depth of the lower end portion of the groove may be smaller than the depth of the upper end portion of the groove. Also, the width of the lower end portion of the groove may be smaller than the width of the upper end portion of the groove. Also, one end of the groove may be exposed from the coating 20, and the other end may be located in the contraction portion 40'b.

[0048] The groove located in the region where the coating 20 is disposed is defined as the first groove 11, and the groove located in the region where the surface of the substrate 10 is exposed from the coating 20 is defined as the second groove 12. The first groove 11 may or may not be connected to the second groove 12. That is, the first groove 11 and the second groove 12 may be formed as a continuous groove. The upper end portion of the first groove 11 may be bent toward the inner portion 13 side. In other words, the first groove 11 may have a first portion 11a extending in the vertical direction of the substrate 10 and a second portion 11b connected to the first portion 11a and having a component along the width direction of the substrate 10. The depth of the second groove 12 may be smaller than the depth of the first groove 11.

[0049] The substrate 10 may have a plurality of grooves. Further, the substrate 10 may include a first groove set 15 in which the first groove 11 and the second groove 12 are connected, and a second groove set 16 in which the first groove 11 and the second groove 12 are connected and the first groove 11 extends to the upper end portion of the coating 20 more than the first groove set 15.

[0050] Furthermore, the substrate 10 may include a plurality of the first groove sets 15. The plurality of the first groove sets 15 may be arranged in the width direction of the substrate 10. Among the plurality of the first groove sets 15, the first groove set 15 located on the outer portion 14 side may be located above the first groove set 15 located on the inner portion 13 side.

[0051] The artificial joint stem 104 shown in FIG. 11 is also included in the artificial joint stem according to the present disclosure. For example, the substrate 10 may include a plurality of grooves, and the groove located at the upper portion of the substrate 10 may have a larger width than the groove located at the lower portion of the substrate 10. The groove may have a component along the width direction of the substrate 10. FIG. 12 shows a C-C' cross section of FIG. 11. As shown in FIG. 12, the groove along the width direction of the substrate 10 may become shallower upward.

[0052] The edge of the lower end of the coating 20 (the first boundary line 1) may intersect the straight portion of the groove. Here, the first boundary line 1 may intersect the straight portion of the groove obliquely. That is, the first boundary line 1 does not have to be orthogonal to the straight portion of the groove.

[0053] Further, the first boundary line 1 may have a first portion 1a extending in a direction intersecting the groove and a second portion 1b extending in a direction along the groove. The second portion 1b may be arranged away from the groove. That is, the second portion 1b may not be in contact with the groove. The same applies to the edge (second boundary line 2) at the upper end of the coating 20.

[0054] The first groove 11 and the second groove 12 are connected, and the first groove 11 may have a first portion 11a extending in the vertical direction of the base 10 and a second portion 11b connected to the first portion 11a and having a component along the width direction of the base 10. As shown in FIG. 11, the second boundary line 2 may extend in a direction along the second portion 11b of the first groove 111.

[0055] Also, as shown in FIG. 11, the second boundary line 2 may be arranged to incline upward from the inner portion 13 toward the outer portion 14. Also, as shown in FIG. 11, the first boundary line 1 may be located below the apex 13a of the concave portion in the inner portion 13. The first boundary line 1 may be located below the apex 14a of the convex portion in the outer portion 14. Alternatively, the first boundary line 1 may be located above the apex 14a of the convex portion in the outer portion 14.

[0056] The artificial joint stem 105 shown in FIG. 13 is also included in the artificial joint stem according to the present disclosure. For example, the boundary line defined by the presence or absence of the coating 20 and the groove may intersect at an acute angle. In FIG. 13, among the angles formed by the first boundary line 1 and the second groove 12, the angle γ on the inner portion 13 side is an acute angle.

[0057] The artificial joint stem 106 shown in FIG. 14 is also included in the artificial joint stem according to the present disclosure. For example, the base body 10 includes a rough surface region 70, a non-rough surface region 80, and a groove region 90 in order from above. A rough surface is disposed in the rough surface region 70. The non-rough surface region 80 is a region where no rough surface is disposed. Grooves are disposed in the groove region 90. For example, the rough surface region 70 may be a region where a rough surface is disposed but no groove is disposed, the non-rough surface region 80 may be a region where neither a rough surface nor a groove is disposed, and the groove region 90 may be a region where no rough surface is disposed and grooves are disposed. The coating 20 may cover at least any one of the rough surface region 70, the non-rough surface region 80, and the groove region 90. The area of the rough surface region 70 may be smaller than the area of the non-rough surface region 80. In the width direction of the base body 10, the length of the rough surface region 70 may be larger than the length of the non-rough surface region 80. The boundary line 23 between the rough surface region 70 and the non-rough surface region 80 may be inclined upward from the inner portion 13 toward the outer portion 14. The length L3 on the inner portion 13 side of the rough surface region 70 may be smaller than the length L4 on the outer portion 14 side of the rough surface region 70. Here, the length L3 represents the difference in the Y coordinate between the point where the Y coordinate is maximum and the point where the Y coordinate is minimum on the inner portion 13 side of the rough surface region 70. The length L4 represents the difference in the Y coordinate between the point where the Y coordinate is maximum and the point where the Y coordinate is minimum on the outer portion 14 side of the rough surface region 70.

[0058] The artificial joint stems 100A to 100F shown in FIGS. 15 to 20 are also included in the artificial joint stem according to the present disclosure. For example, grooves 220A may be provided as in the artificial joint stem 100A, holes 200B may be provided as in the artificial joint stem 100B, grooves 220C may be provided as in the artificial joint stem 100C, grooves 220D may be provided as in the artificial joint stem 100D, grooves 220E may be provided as in the artificial joint stem 100E, and holes 200F may be provided as in the artificial joint stem 100F. Further, in the above example, an example where there are exposed regions at the upper and lower ends of the coating 20 has been described. However, as shown in FIG. 17, the exposed region may be located only on the upper side of the coating 20.

[0059] The manufacturing method of the artificial joint stem according to one embodiment includes a preparation step, a roughening step, and a film formation step. The preparation step prepares a substrate 10 having a surface including a first region and a second region and a roughening region overlapping at least a part of the first region. After preparing the substrate 10, the roughening step is a step of forming a rough surface on the roughening region of the prepared substrate 10. The film formation step is a step of forming a film 20 including a calcium phosphate-based material and an antibacterial material on the first region of the substrate 10. Note that at least a part of the first region and a part of the roughening region overlap. As a result, the film 20 is formed on the rough surface, and a part of the rough surface is exposed from the film 20.

[0060] In the preparation step, the substrate 10 can be prepared by shaping a metal material into a desired shape by means of a mold, a layered manufacturing method, or the like. In the substrate 10, since the second region is positioned so as to sandwich the first region in the vertical direction, after the film 20 is formed, the first boundary line and the second boundary line can be formed. Also, the shapes of the first boundary line and the second boundary line of the film can be adjusted according to the shape of the first region.

[0061] In the roughening step, a rough surface can be formed by at least any one of a spraying method, a layered manufacturing method, a chemical etching method, and a blasting method. Compared with the blasting method, the spraying method, the layered manufacturing method, or the chemical etching method can increase the surface roughness. As the spraying material and the layered manufacturing material, the materials exemplified as the material of the substrate 10 can be used. The above-described layered structure may be formed by the spraying method or the layered manufacturing method. Examples of the chemical etching method include alkali treatment. Examples of the blasting method include sandblasting. Note that the formation of the rough surface can be performed before forming the film 20.

[0062] ​In order to form a rough surface only in the desired region, a first protective material may be used. In this case, before the roughening step, a step of arranging the first protective material to protect other regions while exposing the roughening region so that a rough surface is not formed outside the roughening region may be further included. Note that a part of the roughening region overlaps with a part of the first region. That is, the first protective material may be arranged to protect a part of the first region and the second region. Note that after the roughening step and before the film forming step, a step of removing the first protective material may be included.

[0063] As the first protective material, for example, a masking tape or a partition may be used. Alternatively, as the first protective material, a jig that covers the substrate 10 may be used. Examples of the materials of these first protective materials include metals, glasses, resins, and composite materials thereof. Note that the first protective material may or may not be in contact with the substrate 10. When a jig that covers the substrate 10 is used as the first protective material, the shape of the jig is not particularly limited, and for example, it may be cylindrical. The cross section of the cylindrical jig may be polygonal or circular.

[0064] When placing the baffle, a rough surface can be formed in a specific area by installing the baffle at a predetermined position. When using a jig, a rough surface can be formed in a specific area by installing the jig at a predetermined position. In this case, for example, by adjusting the positional relationship between the discharge nozzle that discharges the spraying material, additive manufacturing material, chemical etching material, blasting material, or coating material and the baffle, a rough surface can also be selectively formed only in a desired area. In this case, the tip of the discharge nozzle may be arranged in a straight line without separating from the surface of the desired area and the baffle, for example. Further, hereinafter, the spraying material, additive manufacturing material, chemical etching material, blasting material, or coating material discharged from the discharge nozzle is also referred to as a discharge material. Without being limited to these, with the substrate 10, the baffle, and the discharge nozzle fixed, a rough surface may be formed, or a rough surface may be formed while moving at least one of them. Also, the angle of the discharge nozzle may be fixed, or a rough surface may be formed while changing the angle. Note that, similar to the coating 20, a rough surface may be formed only in a desired area without using a protective material.

[0065] Note that a rough surface can also be formed only in a desired area without using a protective material. For example, by adjusting the shape, angle, or position of the discharge nozzle that discharges the discharge material, a rough surface can also be selectively formed only in a desired area. For example, the discharge material may be discharged in a state where the discharge nozzle is positioned upward from the surface of the desired area. In this case, the substrate 10 may be fixed, and a rough surface may be formed while moving the position and angle of the discharge nozzle, or the discharge nozzle may be fixed, and the coating 20 may be formed while moving the position and angle of the substrate 10. The discharge nozzle may be moved at a constant speed or may be moved while changing the speed. Also, the discharge direction of the discharge material may form an angle of 90° with the vector extended toward the substrate 10 or the surface of the rough surface that is at the shortest distance from the tip of the discharge nozzle to the tip of the discharge nozzle, or may form an angle of less than 90°.

[0066] The formation of the film 20 can be carried out, for example, by spraying methods such as flame spraying, high-speed flame spraying, and plasma spraying; physical vapor deposition methods or chemical vapor deposition methods such as sputtering, ion plating, ion beam evaporation, and ion mixing methods; or wet coating methods such as the sol-gel method. The film 20 may be formed so as to cover at least a part of the embedded portion.

[0067] In order to form the film 20 only in the first region, a second protective material may be used. In this case, before the film formation step, there may further be a step of disposing the first protective material so as to protect the second region while exposing the first region so that no film is formed in the second region. As the second protective material, for example, a masking tape or a partition may be used. Alternatively, as the second protective material, a jig covering the substrate 10 may be used. Examples of the materials of these second protective materials include metals, glass, resins, and composite materials thereof. Note that the second protective material may or may not be in contact with the substrate 10. When, for example, a masking theme is used as the first protective material, the second protective material may be disposed in the shape of the second region. When a jig covering the substrate 10 is used, the shape of the jig is not particularly limited, and for example, it may be cylindrical. The cross section of the cylindrical jig may be polygonal or circular. Note that after the film formation step, there may be a step of removing the second protective material.

[0068] When arranging the baffle, by installing the baffle at a predetermined position, the film 20 can be formed in a specific region. When using a jig, by installing the jig at a predetermined position, the film 20 can be formed in a specific region. In this case, for example, by adjusting the positional relationship between the ejection nozzle that ejects the spraying material, the additive manufacturing material, the chemical etching material, the blasting material, or the coating material and the baffle, the film 20 can also be selectively formed only in a desired region. In this case, the tip of the ejection nozzle may be arranged in a straight line without a gap from the surface of the desired region and the baffle. Further, hereinafter, the spraying material, the additive manufacturing material, the chemical etching material, the blasting material, or the coating material ejected from the ejection nozzle is also referred to as an ejection material. Without being limited to these, the film 20 may be formed with the substrate 10, the baffle, and the ejection nozzle fixed, or the film 20 may be formed while moving at least one of them. Also, the angle of the ejection nozzle may be fixed, or the film 20 may be formed while changing the angle.

[0069] Note that the film 20 can also be formed only in a desired region without using a protective material. For example, by adjusting the shape, angle, or position of the ejection nozzle that ejects the ejection material, the film 20 can also be selectively formed only in a desired region. For example, the ejection material may be ejected in a state where the ejection nozzle is positioned upward from the surface of the desired region. In this case, the substrate 10 may be fixed and the film 20 may be formed while moving the position and angle of the ejection nozzle, or the ejection nozzle may be fixed and the film 20 may be formed while moving the position and angle of the substrate 10. The ejection nozzle may be moved at a constant speed or may be moved while changing the speed. Also, the ejection direction of the ejection material may form an angle of 90° with the vector extended toward the surface of the substrate 10 or the rough surface that is at the shortest distance from the tip of the ejection nozzle to the tip of the ejection nozzle, or may form an angle of less than 90°.

[0070] For example, in the roughening step, a protective material may be disposed on the substrate 10 so as to expose the area to be roughened while protecting other areas, and a rough surface may be formed on the exposed area. Further, the manufacturing method according to the present disclosure may further include a step of removing the protective material after the roughening step and before the film forming step. Further, after removing the protective material, a step of trimming the edge of the rough surface, for example, the edge of the layered member 30, may be performed. Thereby, concentration of stress at the edge of the layered member 30 can be avoided, and stimulation to the living tissue can be reduced.

[0071] The manufacturing method of the artificial joint stem according to one embodiment may further include a recess forming step before the film forming step. In the recess forming step, for example, at least one recess 2X can be formed on the surface of the substrate 10 by at least one of a cutting method, a rolling method, and a pressing method. After the recess 2X is formed on the surface of the substrate 10 by the recess forming step, a film may be formed on the surface of the substrate 10 including the inner surface of at least one recess 2X by the film forming step.

[0072] Summarizing the above matters, for example, each step can be performed in the order shown in FIG. 8. FIG. 8 is a process diagram showing a manufacturing method of an artificial joint stem according to one embodiment. First, a protective material is disposed (S101), and then after performing the roughening step (S102), the protective material can be removed (S103). Next, the film forming step can be performed (S104).

[0073] Furthermore, the manufacturing method according to the present disclosure may or may not include a cleaning step between each step. For example, the manufacturing method according to the present disclosure may include a step of cleaning the substrate 10, or the substrate 10 and the layered member 30, after the roughening step. The cleaning method is not particularly limited, and for example, it may be a method of immersing in a liquid such as water or an organic solvent such as alcohol, or showering using the liquid. Alternatively, it may be a method of spraying a gas such as air, nitrogen, or argon. Thereby, excess thermal spraying material or the like generated by the roughening step can be removed.

[0074] Note that the roughening process may sequentially include a first roughening process of forming a first rough surface by a spraying method and a second roughening process of forming a second rough surface by a chemical etching method or a blasting method. Here, the region where the first rough surface is formed by the spraying method is referred to as a first roughening region, the region where the second rough surface is formed by the chemical etching method or the blasting method is referred to as a second roughening region, and the region where no rough surface is formed is referred to as a non-roughening region.

[0075] In the first roughening process, a protective material may be arranged on the substrate 10 so as to protect the second roughening region and the non-roughening region while exposing the first roughening region, and the first rough surface may be formed on the exposed first roughening region. Further, the manufacturing method according to the present disclosure may further include a step of removing the protective material after the first roughening process and before the second roughening process. In the second roughening process, a protective material may be arranged on the substrate 10 so as to protect the non-roughening region while exposing the second roughening region, and the second rough surface may be formed on the exposed second roughening region. The second roughening process may be performed such that the surface of the second rough surface formed in the second roughening process has a smaller surface roughness than the surface of the first rough surface in the first roughening region. Further, the manufacturing method according to the present disclosure may include a step of removing the protective material after the second roughening process and before the film forming process. As the protective material, for example, a masking tape may be used. The manufacturing method according to the present disclosure may further include a step of attaching a masking tape to the non-roughening region while exposing the first roughening region and the second roughening region before the second roughening process. As the protective material, a material having a lower heat resistance than the protective material used in the above-described first roughening process may be used. For example, a material that is difficult to dissolve or thermally decompose at room temperature may be used as the protective material. Specifically, a resin may be used as the protective material.

[0076] In the second roughening step, the non-roughened region may or may not be covered by a protective material. The first roughened region and the non-roughened region may be protected, and at least one of processing by a chemical etching method and processing by a blasting method may be performed only on the second roughened region. Alternatively, a protective material may be arranged so as to expose the first roughened region, and at least one of processing by a chemical etching method and processing by a blasting method may be performed on the roughened surface of the exposed first roughened region and the second roughened region. Thereby, excess thermal spraying material or the like remaining on the roughened surface of the first roughened region can be removed, and a roughened surface can also be formed on the second roughened region.

[0077] [3. Use of the stem for artificial joint] The artificial joint stem 100(101) is mainly shaped assuming an artificial femoral joint stem, but the artificial joint to which the artificial joint stem according to the present disclosure is applied is not limited to an artificial femoral joint. Examples of the artificial joint include an artificial femoral joint, an artificial knee joint, an artificial ankle joint, an artificial shoulder joint, an artificial elbow joint, and an artificial finger joint.

[0078] Hereinafter, an example of using the artificial joint stem 100(101) as a part of the artificial femoral joint 1000 will be described with reference to FIG. 7. The artificial femoral joint 1000 may include a femoral head 110 and an acetabular cup 120 in addition to the artificial joint stem 100(101). The femoral head 110 and the acetabular cup 120 may be formed of the same material as the base 10 of the artificial joint stem 100(101), or may be formed of different materials. The artificial joint stem 100(101) is implanted in the femur 91. The femoral head 110 is disposed on the exposed portion 50 of the artificial joint stem 100(101). The acetabular cup 120 is fixed to the acetabulum 94 of the hip bone 93. By fitting and sliding the femoral head 110 into the recess of the acetabular cup 120, it functions as a hip joint.

[0079] The invention according to the present disclosure has been described above based on the drawings and examples. However, the invention according to the present disclosure is not limited to each of the above-described embodiments. That is, the invention according to the present disclosure can be variously modified within the scope shown in the present disclosure, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the invention according to the present disclosure. In other words, it should be noted that those skilled in the art can easily make various deformations or modifications based on the present disclosure. Also, it should be noted that these deformations or modifications are included in the scope of the present disclosure.

Explanation of Reference Numerals

[0080] 2 Concave portion 10 Substrate 10C Coated region 20, 20A Coating 21, 21A Rough surface 30 Layered member 100, 101 Stem for artificial joint 200, 210 Hole 211, 211A Exposed region 220 Groove 1000 Artificial hip joint

Claims

1. a roughening step of forming a rough surface on the surface of the substrate; and forming a coating film containing a calcium phosphate-based material and an antibacterial material on at least a portion of the surface of the substrate, A method for manufacturing an artificial joint stem, wherein in the coating formation process, the rough surface has an exposed area exposed from the coating so that only a portion of the area of ​​the base surface where the rough surface is formed overlaps with at least a portion of the area where the coating is formed, and the exposed area is formed so as to be located on the lower end side of the coating when the distal side of the human body when the artificial joint stem is used is oriented downward.

2. The method for producing an artificial joint stem according to claim 1 , wherein the coating step is performed after the surface roughening step.

3. The method for manufacturing an artificial joint stem according to claim 1 , wherein in the coating forming step, the coating is formed so that only a portion of the area where the rough surface is formed in the roughening step overlaps with the entire area where the coating is to be formed.

4. The method for manufacturing an artificial joint stem according to claim 1 , further comprising a preparation step of forming a metal material to prepare the base body.

5. 5. The method for manufacturing an artificial joint stem according to claim 4, wherein the metal material is a stainless steel alloy, a cobalt-chromium alloy, titanium or a titanium alloy.

6. 2. The method for manufacturing an artificial joint stem according to claim 1, wherein the surface roughening step is a step of forming the rough surface by at least one of a thermal spraying method, an additive manufacturing method, a chemical etching method, and a blasting method.

7. The method for manufacturing an artificial joint stem according to claim 6, wherein the roughened surface is formed by a thermal spraying method or an additive manufacturing method in the surface roughening step.

8. 2. The method for manufacturing an artificial joint stem according to claim 1, wherein the surface roughening step includes a step of forming a rough surface by a thermal spraying method, and a step of forming a rough surface by a chemical etching method or a blasting method.

9. The method for manufacturing an artificial joint stem according to claim 1 , wherein the surface roughening step includes a step of forming a layer member on the base body.

10. 10. The method of claim 9, wherein in the step of forming the layer member, the layer member is formed from the same material as the base body.

11. 10. The method of claim 9, wherein in the step of forming the layered member, the layered member is formed of a titanium alloy.

12. The method for manufacturing an artificial joint stem according to claim 1, further comprising, prior to the roughening step, a step of placing a first protective material to expose the area where the roughened surface is to be formed while protecting the area where the roughened surface is not to be formed.

13. The method for producing an artificial joint stem according to claim 12, further comprising a step of removing the first protective material after the surface roughening step and before the coating step.

14. The method for producing an artificial joint stem according to claim 1 , further comprising the step of cleaning said base body and said roughened surface after said surface roughening step.

15. 2. The method for manufacturing an artificial joint stem according to claim 1, further comprising, prior to the coating forming step, a step of placing a second protective material to protect the area where the coating is not to be formed while exposing the area where the coating is to be formed.

16. The method for manufacturing an artificial joint stem according to claim 1 , wherein the antibacterial material is an inorganic antibacterial agent.

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