Bone joint implant

Abstract

A bone joint implant (1) has a proximal portion (120) for translational movement over a metacarpal bone in a first carpometacarpal joint and a distal portion (110) for intramedullary engagement in a first metacarpal bone. An articulating link (103, 121, 123) is for polyaxial movement in which one portion (120) moves translationally over a bone and the other portion (110) rotates about the articulating link (121, 103). A flange (105) extends radially and about the link to limit relative rotational movement of the proximal and distal portions about the link and to provide resilience for contact between the proximal and distal portions. The flange has a profile surface (101) which in use mates with an abutment surface (125) of the proximal portion (122) when the portions articulate to a limit position. The flange (105) is included in an insert (100) in a stem (111) of the distal portion (110), the flange extending proximally of the stem (111) and preventing contact between the proximal portion (120) and the stem (111) during articulation.

Description

[0001] Cross-references of related applications

[0002] This application claims the benefit of priority to U.S. Provisional Applications No. 62 / 823,367 and No. 62 / 823,392, filed March 25, 2019; U.S. Provisional Applications No. 62 / 847,719, filed May 14, 2019; and U.S. Utility Model Patent Application No. 16 / 678,552, filed November 8, 2019, all of which are incorporated herein by reference in their entirety. Technical Field

[0003] This invention relates to an implant for bone and joint use. In some examples, it relates to implants having multiple axes of rotation, such as those in biaxial hemiarthroplasty with two axes of rotation, for example, in the hand or elbow. However, in other aspects, this invention relates to uniaxial implants, such as hip implants. Background Technology

[0004] An example of an implant with multiple axes of rotation is an implant for the first carpometacarpal joint, used to separate the trapezium from the first metacarpal. In this case, due to the articulated connection (e.g., a ball-and-socket joint), there is translational movement of the saddle-shaped surface of the proximal implant portion on the trapezium and three-dimensional rotational movement of the distal portion. An example of such an implant is described in WO2017 / 137607 (NUIG).

[0005] In such implants, the points of motion can be simultaneously or independently at two points or between two points. Depending on the biomechanics of the joint into which the implant is inserted, the dominant kinetic force may change rapidly and abruptly between the two points. Figures 1(a) and 1(b) illustrate biaxial implants that provide two axes of rotation: Ab-Ad (axis 1) at the base of the metacarpal and Ex-Fl (axis 2) on the surface of the trapezium to reconstruct the original axes of rotation of the joint. A ray-transparent rod is used in Figure 1(a) to illustrate the location of the ball-and-socket joint within the metacarpal.

[0006] Impacts can occur at any time when the space between two components is reduced, causing one component to impact the other, for example, the head of a hemiarthroplasty head hitting a bar.

[0007] Uncontrolled impingement is a cause of poor implant outcomes. This also applies to uniaxial implants, such as prosthetic hip replacements; it can lead to instability, accelerated wear, and unexplained pain. Impingement is influenced by prosthesis design, component placement, biomechanical factors, and patient variability. Uncontrolled impingement is associated with dislocation, and accelerated wear is observed in implant removal studies. Operational principles for maximizing impingement-free range of motion include proper acetabular and femoral anteversion and an optimal head-neck ratio. Surgical techniques for preventing impingement include mediating the cup to avoid component impingement and restoring hip offset and length to avoid bone impingement.

[0008] To illustrate these issues, Figure 1(c) is from Brown TD, Callaghan JJ. Impingement in Total Hip Replacement: Mechanisms and Consequences. Curr Orthop. 2008; 22(6):376-391. These figures show the finite element analysis of the restraint pad THA, illustrating the stress profile (A, B) at the moment of initial dislocation. Figure 1(d), also from Brown TD, Callaghan JJ. Impingement in Total Hip Replacement: Mechanisms and Consequences. Curr Orthop. 2008; 22(6):376-391, shows a 3D finite element model of total hip dislocation, illustrating the initial relative positions of the implant components (left), the acetabular component subjected to surface stress during stabilization articulation (middle), and the corresponding stress just before the hip dislocation event (right).

[0009] The present invention aims to provide an improved implant that has controlled impact, or at least reduces the impact of an impact. Summary of the Invention

[0010] We describe implants as described in appended claims 1 to 23, and plugs for such implants as described in appended claims 24 to 26.

[0011] This disclosure includes osteoarticular implants. For example, this disclosure includes an osteoarticular implant for a first carpometacarpal joint in a mammal, comprising: a proximal metallic platform configured for translational movement on a trapezium bone; a distal rod configured for intramedullary engagement with the distal end of a first metacarpal bone; a hinged connection between the proximal platform and the distal rod; and a proximal nonmetallic wear surface and a distal nonmetallic wear surface.

[0012] According to some examples herein, the proximal nonmetallic wear surface may form a buffer surface that prevents contact between the proximal platform and the rod during articulation; may include concave curvature; and / or may form an annular surface. The proximal platform may include a distal end surface with convex curvature. In at least one example, the distal nonmetallic wear surface may be shaped as a sphere.

[0013] In some examples, the implant may include a monolithic nonmetallic wear member, and proximal and distal nonmetallic wear surfaces may be formed on the monolithic wear member. The monolithic nonmetallic wear member may be an insert received in the proximal end surface of the rod, and the insert may include a proximal portion extending proximally toward the proximal end surface of the rod. In some examples, the proximal portion may be a flange of the insert, and the flange may include the proximal nonmetallic wear surface; and / or, the hinged connection may be a ball-and-socket connection, and the insert may form a socket in the ball-and-socket connection.

[0014] This disclosure also includes an osteoarticular implant for a first carpometacarpal joint in mammals, comprising: a proximal portion configured for translational movement on a trapezium bone, the proximal portion including a platform; a distal portion configured for intramedullary engagement with an end portion of a first metacarpal bone, the distal portion including a rod and a wear surface located proximal to the rod; and a hinged connection between the proximal and distal portions, further positioning the wear surface to limit the hinge and prevent contact between the platform and the rod. In at least one example, the wear surface may be nonmetallic and the platform may be metallic. The wear surface may include concave curvature and / or may form an annular surface. The platform may include a distal end surface having convex curvature.

[0015] In some examples, the implant may include an insert received in the proximal end surface of the rod, wherein a worn surface is formed on the insert. The insert may include a proximal flange, wherein a worn surface is formed on the flange. Furthermore, the articulated connection may be a ball-and-socket connection, and the ball may be formed part of the proximal portion, and the socket may be formed by the insert. In at least one example, the ball may extend distally to the flange.

[0016] This disclosure also includes an osteoarticular implant for a first carpometacarpal joint in mammals, comprising: a proximal portion configured for translational movement on a trapezium bone, the proximal portion including a platform; a distal portion configured for intramedullary engagement with an end portion of a first metacarpal bone, the distal portion including a rod and an insert extending into a proximal end portion of the rod, the insert including a flange extending proximally from the proximal end portion of the rod; and a hinged connection between the proximal and distal portions, the flange including a proximal end portion surface that restricts movement between the proximal and distal portions. In at least one example, the insert may be nonmetallic and the platform may be metallic. The proximal end portion surface of the flange may have a concave curvature and / or the platform may include a distal end portion surface having a convex curvature. In at least one example, the flange may be annular. Furthermore, the hinged connection may be a ball-and-socket connection, the proximal portion may include a ball and the insert may include a socket, and / or the ball may extend distally to the flange.

[0017] This disclosure also includes an osteoarticular implant for a first carpometacarpal joint in mammals, comprising: a proximal portion configured for translational movement on a trapezium bone, the proximal portion including a metal platform having a proximal end surface with concave curvature and a distal end surface with convex curvature; a distal portion configured for intramedullary engagement with the end portion of a first metacarpal bone, the distal portion including a metal rod and a nonmetallic insert extending into the proximal end portion of the rod, the insert including a flange extending proximally toward the proximal end portion of the rod; and a ball-and-socket connection between the proximal and distal portions, the proximal portion including a ball, the insert including a socket, and the flange including a proximal end surface that restricts movement between the proximal and distal portions. According to some examples, the proximal end surface may include a concave surface and / or the proximal end surface may be annular.

[0018] We have described osteoarthritic implants for the first carpometacarpal joint in mammals in other examples, including

[0019] Construct a proximal metal platform for translational movement on the trapezium;

[0020] Construct a distal rod for intramedullary engagement with the end of the first metacarpal bone;

[0021] A hinged connection between the proximal pedestal and the distal rod; and

[0022] Proximal non-metallic wear surface and distal non-metallic wear surface.

[0023] Preferably, the proximal nonmetallic wear surface forms a buffer surface that prevents contact between the proximal platform and the rod during hinge. Preferably, the proximal nonmetallic wear surface includes a concave curvature. Preferably, the proximal platform includes a distal end surface with a convex curvature. Preferably, the proximal nonmetallic wear surface forms an annular surface. Preferably, the distal nonmetallic wear surface is spherical. Preferably, the implant further includes an integral nonmetallic wear member, and the proximal and distal nonmetallic wear surfaces are formed on the integral wear member. Preferably, the integral nonmetallic wear member is an insert received in the proximal end surface of the rod, and the insert includes a proximal portion extending proximally to the proximal end surface of the rod. Preferably, the proximal portion is a flange of the insert, and the flange includes the proximal nonmetallic wear surface. Preferably, the hinge connection is a ball-and-socket connection, and the insert forms the socket of the ball-and-socket connection integral.

[0024] On the other hand, we describe an osteoarthritic implant for the first carpometacarpal joint of a mammal, comprising:

[0025] A proximal portion is constructed for translational movement on the trapezium bone, the proximal portion including a pedestal;

[0026] A distal portion is constructed for intramedullary engagement with the distal end of the first metacarpal bone, the distal portion including a shaft and a wear surface located proximal to the shaft; and

[0027] A hinged connection device between the proximal and distal portions.

[0028] The worn surface is further positioned to limit the hinge and prevent contact between the pedestal and the rod.

[0029] Preferably, the wear surface is non-metallic, and the base is metallic. Preferably, the wear surface includes a concave curvature. Preferably, the base includes a distal end surface with a convex curvature. Preferably, the wear surface forms an annular surface. Preferably, the implant further includes an insert received in the proximal end surface of the rod, on which the wear surface is formed. Preferably, the insert includes a proximal flange, and the wear surface is formed on the flange. Preferably, the hinged connection is a ball-and-socket connection, and the ball forms part of the proximal portion, and the socket is formed by the insert. Preferably, the ball extends distally to the flange. Preferably, the wear surface includes a concave curvature.

[0030] We also describe an osteoarticular implant for the first carpometacarpal joint in mammals, comprising:

[0031] The proximal portion is constructed for translational movement on the trapezium, and the proximal portion includes a pedestal;

[0032] The distal portion, configured for intramedullary engagement with the distal end of the first metacarpal bone, includes a rod and an insert extending into the proximal end of the rod, the insert including a flange extending proximally toward the proximal end of the rod; and

[0033] The hinged connection between the proximal and distal portions, and

[0034] A flange includes a proximal end surface that restricts movement between a proximal portion and a distal portion.

[0035] Preferably, the insert is non-metallic and the base is metallic. Preferably, the proximal end surface of the flange has a concave curvature. Preferably, the base includes a distal end surface with a convex curvature. Preferably, the flange is annular. Preferably, the hinged connection is a ball-and-socket connection, and the proximal portion includes a ball, and the insert includes a socket. Preferably, the ball extends distally towards the flange.

[0036] In other examples, we describe osteoarthritic implants for the first carpometacarpal joint in mammals, including:

[0037] The proximal portion, constructed for translational movement on the trapezium, includes a metal platform having a proximal end surface with concave curvature and a distal end surface with convex curvature.

[0038] The distal portion, configured for intramedullary engagement with the distal end of the first metacarpal bone, includes a metallic rod and a non-metallic insert extending into the proximal end of the rod, the insert including a flange extending proximally toward the proximal end of the rod; and

[0039] A ball-and-socket connection device between a proximal portion and a distal portion, the proximal portion including a ball, and the insert including a socket, and

[0040] A flange includes a proximal end surface that restricts movement between a proximal portion and a distal portion.

[0041] Preferably, the proximal end surface includes a concave surface. Preferably, the proximal end surface is annular.

[0042] We also describe bone and joint implants in various aspects, including:

[0043] Proximal portion,

[0044] The remote part,

[0045] The hinged connection between the proximal and distal portions, and

[0046] A buffer interface is constructed to limit relative rotational movement around the coupling device and / or to provide elasticity for contact between the proximal and distal portions.

[0047] Preferably, the interface includes a flange extending radially around at least some of the coupling devices. Preferably, the flange is made of a material that is more elastic than the material it contacts.

[0048] Preferably, the flange has a profiled surface that mates with the adjacent surface of the component when the portion is hinged to its limit position during use. Preferably, the flange profiled surface is annular. Preferably, the flange is included in the distal portion.

[0049] Preferably, the flange is included in the insert within the distal portion.

[0050] Preferably, the thickness of the flange is in the range of 0.5 mm and 4.0 mm, more preferably in the range of 1.0 mm and 3 mm.

[0051] Preferably, the buffer interface is a polymer material. Preferably, the material of the buffer interface is non-metallic and different from the material of the contact surface.

[0052] Preferably, the interface is configured to provide a cone of motion between 30° and 50° around the proximal portion by the distal portion. Preferably, the insert includes components of a hinged connection device.

[0053] Preferably, the connecting device is a ball-and-socket connecting device, and the insert includes a socket for the connecting device. Preferably, the insert includes a locking feature for snap-fitting into another distal portion component. Preferably, the locking feature is the distal annular edge of the insert.

[0054] The implant can be configured for multi-axial motion. Preferably, the implant (1) is configured to translate over the bone in one part and rotate about the articulated connection in another part.

[0055] The implant can be used in the first carpal and metacarpal joint of a mammal, with a first portion for translational movement on the trapezium and a distal portion for intramedullary engagement with the end of the first metacarpal.

[0056] The interface may include distal-facing features on the proximal portion. These distal-facing features may include a coating on the proximal portion. The coating thickness may range from 0.5 mm to 3.0 mm, and preferably from 1.0 mm to 2.0 mm, and is preferably made of a polymer material.

[0057] We also describe a bone and joint implant, comprising:

[0058] Proximal portion,

[0059] The remote part,

[0060] The hinged connection between the proximal and distal portions, and

[0061] A flange is constructed to limit relative rotational movement about the connecting device.

[0062] The implant is used in the first carpal joint of a mammal, and the first portion is configured to translate on the trapezium, and the distal portion is configured to engage intramedullary with the end of the first metacarpal.

[0063] Preferably, the flange is part of the insert that engages in the first proximal or distal portion.

[0064] We also describe a bone and joint implant in which:

[0065] The flange is made of an elastic material.

[0066] The flange has an annular profile surface that, when partially hinged to its limit position during use, matches the adjacent surface of that portion.

[0067] The flange is located at the distal end.

[0068] We also describe an insert for a bone joint implant, the bone joint implant including a proximal portion, a distal portion, and a hinged connection between the proximal and distal portions, wherein the insert is configured to engage one of these portions and includes a flange configured to restrict relative rotation about the connection.

[0069] Preferably, the insert is configured as an implant for a mammalian first carpometacarpal joint, wherein a first portion is configured for translational movement on the trapezium and a distal portion is configured for intramedullary engagement with the distal end of the first metacarpal, and wherein:

[0070] The flange is made of an elastic material, and / or

[0071] The flange has an annular profile surface that, during use, mates with the adjacent surface of that portion when partially hinged to its limit position, and / or

[0072] The plug-in is configured to attach to the remote portion.

[0073] In one respect, implants are designed for uniaxial rotation. For example, implants can be used in the hip, shoulder, or elbow joints.

[0074] The buffer interface may include a cushioning liner, and the liner provides an interface surface for contacting a component, such as the neck of a coupling device. Attached Figure Description

[0075] The present invention will be more clearly understood through the following description of some embodiments thereof, given by way of example only, and with reference to the accompanying drawings, wherein:

[0076] Figures 1(a) and 1(b) are diagrams illustrating different axes of motion of an implant for a first carpometacarpal joint in the prior art, which is used to separate the trapezium from the first metacarpal, as discussed in the introduction above (technical field and background art).

[0077] Figure 1(c) is a finite element analysis (FEA) diagram showing the impact in the hip joint in the prior art, and Figure 1(d) is also a FEA diagram of the hip joint showing the impact and exit location in the prior art, as described in the introduction (technical field and background art) above;

[0078] Figure 2 This is a perspective view showing the proximal and distal portions of the implant of the present invention;

[0079] Figure 3(a) is a cross-sectional view through the distal portion of the implant, Figure 3(b) is a perspective view of the rod of the distal portion, Figure 3(c) is a perspective view of the complete distal portion, and Figure 3(d) is a perspective view of the proximal portion.

[0080] Figure 4 It is a set of diagrams showing a portion of the distal part of the implant, including top plan view, end view, perspective view and cross-sectional view;

[0081] Figure 5 It is a set of three pairs of end views and cross-sectional views showing the implant at different relative positions between its proximal and distal portions;

[0082] Figure 6 It is a diagram illustrating the permissible cone of motion between the proximal and distal portions;

[0083] Figure 7(a) and 7(b) The illustration shows a cross-sectional view of the implant, illustrating the areas of material stress.

[0084] Figure 8(a) and 8(b) This shows a cross-sectional view of an implant with an interface coating on the proximal portion; and

[0085] Figure 9 This is a cross-sectional view of an implant for the hip joint, featuring flanges designed to increase surface area and reduce contact stress. Detailed Implementation

[0086] the term

[0087] "Intramedullary suture" refers to a suture within a medullary cavity formed or present in the bone, wherein the cavity typically, but not exclusively, forms along the longitudinal axis of the bone. In one embodiment, the intramedullary suture fixation device includes a screw or nail or interference-fitting rod, but other intramedullary fixation devices are known. Typically, screws have external threads. Intramedullary fixation devices are sold by Smith & Nephew, Zimmer, Synthes, and other suppliers. The suture anchors the implant to the bone. In one embodiment, the medullary cavity is formed at a location offset towards the palmar direction. The medullary cavity may be formed at a location offset from the anatomical and / or biomechanical axes of the bone.

[0088] “Non-jointed adjoint” refers to a proximal portion that is not fixed to the first bone, but is constructed to adjoin the end of the bone in a manner that allows for translational movement. How this is achieved depends on the specific anatomy of the joint being treated and the first bone. As an example, when the joint is the carpometacarpal joint of the thumb, the end of the trapezium bone is shaped like a twisted saddle (see Turker et al., Indian J Plast Surg. 2011, 44(2):308-316). Figure 2 The platform is configured to rest on the saddle and allow translational movement of the platform across the saddle. Therefore, in this embodiment, the curved saddle-shaped platform typically has a concave-convex shape, having a concave curvature in the longitudinal direction and a convex curvature in the transverse direction. The curved saddle-shaped platform can have both concave and convex curvature in both the longitudinal and transverse directions, i.e., in the length and width directions (as shown in the figure, for example...). Figure 2 and Figure 4 This shape has been shown to provide an engagement that closely mimics physiological conditions and allows for natural flexion-extension articulation. When curvature (e.g., concave or convex) is discussed in this disclosure, the reference point is taken from the outside of the structure (implant) or component, not from the inside of the structure or component.

[0089] "Translation of the second bone relative to the first bone" refers to the non-pivotatory movement of the second bone relative to the first bone. This can also be described as a gliding movement. An example is the involuntary translation of the metacarpals relative to the trapezium in the thumb carpometacarpal joint, which significantly contributes to the thumb's flexion-extension articulation. The implant of the present invention facilitates this translational movement by employing a proximal portion configured to non-engulfably abut the first bone.

[0090] "Articulated connection" refers to a connection that allows articulation between the first and second parts of an implant. The specific type of connection used in an implant depends on the joint being treated with the implant, and in some cases, on the indication or the severity of the indication. For example, when an implant is used to treat a hinged joint of arthritis, such as the elbow joint, the implant typically includes a hinged joint connection. When an implant is used to treat a saddle-shaped joint, such as the carpal joint, the implant typically includes a ball-and-socket joint or a universal joint. "Controlled articulation" means that the articulation is restricted to a specific type of articulation.

[0091] A “proximal pedestal” refers to the base of the pedestal adjacent to the end of a first bone (e.g., the end of the trapezium), thereby allowing translational (i.e., sliding) movement of the pedestal relative to the end of the bone. The bone is not fixed to the pedestal. The pedestal can be constructed to conform to the surface of the top of the bone. In one embodiment, the pedestal is shaped to mimic the end of a second bone, thereby allowing the same range of motion as a natural, healthy joint, including translational movements. In the case of a carpometacarpal joint, where the end of the first bone (tragus) has a twisted saddle topography, the shape of the pedestal can conform to the twisted saddle to allow one or more of the following ranges of movement of the first metacarpal relative to the trapezium: flexion, extension, abduction, adduction, internal rotation, external rotation, opposition, circumduction, and translation.

[0092] Description of the Implementation Examples

[0093] refer to Figures 2 to 7(b) The implant 1 has a distal portion and a proximal portion 120, the distal portion having an insert 100 in a rod 110.

[0094] In this configuration, implant 1 is used for the first carpometacarpal joint of a mammal, as shown in Figure 1(a), to separate the trapezium from the first metacarpal, while allowing translational movement of the first metacarpal relative to the trapezium. The distal portion 110 is configured to engage intramedullary with the distal end of the first metacarpal. The proximal portion 120 has a curved saddle-shaped platform 122 with a proximal-facing surface 124 for sliding on or across the trapezium. As is known, articulated coupling devices (e.g., ball-and-socket joints) include a neck 123 bridging the saddle 122 to the ball 121. This allows for controlled articulation of the trapezium and the first metacarpal.

[0095] The plug-in 100 has a buffer interface feature (i.e., a buffer surface), in this case a flange 105 of a proximal-facing surface 101 with a profile, which can be as follows: Figure 5The ring shown. A flange 105 extends proximally to the rod, its profiled surface 101 being at and spaced from the proximal end of the rod 111. This allows it to play a significant role in use due to contact with the proximal portion, for example, as a cushion. At the distal end of this surface is a shoulder 102, which serves as a key for engaging the insert 100 into the rod 111 (see...). Figure 5 This prevents the insert from rotating within the rod and surrounds the socket 103 with edge 106 to receive the hinged connecting ball 121. Ball 121 (see especially Figure 3(d) and...) Figure 5 The snap-fit ​​engagement is located in the socket 103, behind the edge 106 of the socket, to enable intraoperative assembly of the arthroscopic hemiarthroplasty and to prevent disassembly of the device within the body. The socket can be centered or offset in any direction or angle as needed.

[0096] Further distally, the insert 100 includes an annular locking edge 104 for snap-fitting into a corresponding groove 116 of the notch 115 of the rod 111 that receives the insert 100. The engagement of the insert 100 into the rod 111 is effective due to the elasticity of the insert material and the fact that there is full surface-to-surface contact in a snap-fit ​​manner between the edge 104 and its corresponding engagement surface within the rod 111. This snap-fit ​​engagement of the insert 100 and the rod 111 enables intraoperative assembly of arthroscopic hemiarthroplasty and also prevents disassembly of the device within the body. The insert is keyed by a shoulder 102 to prevent rotation and potential subsequent posterior abrasion.

[0097] The flange 105 (and in this case, the entire insert 100) is made of an elastic polymer material, preferably a polymer in any form, such as UHMWPE (in any form, possibly including vitamin E) or PEEK. In this case, the insert 100 may be referred to as an integral nonmetallic wear member. Alternatively, it may be other materials commonly used in orthopedics, such as high-temperature carbon (PyC) or ceramic, depending on the intended wear pattern of the construction. The material of the insert 100 differs from the metallic material of the integral proximal portion 120 (saddle 122, neck 123, and articulated connecting ball 121), thus avoiding any electro-modulated interactions that could lead to excessive wear and / or chemical reactions that produce contaminants. Similarly, for the same reason, the (polymer) material of the insert differs from the metallic material of the rod 111. Metal-to-metal contact interfaces are generally avoided in implants. While polymer materials are advantageous for wear, the biomechanical advantages of the flange, namely separating the two axes of rotation, may be more important, and therefore the flange may be made of any suitable material. One example is where the insert (or "shield") is made of ceramic, but the head is made of PEEK, which still allows for a snap-fit ​​engagement for the articulated joint. It is generally preferred that the flange and socket are not made of relatively hard materials, as relatively hard materials may not allow a snap-fit ​​with any material other than one with low modulus / high resilience. Conversely, for example, if the head is polymer and the shim is ceramic, a soft polymer material can still snap-fit ​​into a hard ceramic socket.

[0098] Therefore, as described above, the implant 1 may include at least one non-metallic wear surface. The non-metallic wear surface may be present at any location where the surfaces of the implant's stem 110 and the base 122 can engage, such as... Figure 5 As shown. When the rod 110 includes the insert 100, the insert 100 may include at least one non-metallic wear surface. The at least one non-metallic wear surface may include a shaped surface, such as a surface with a convex curvature, and / or may form an annular surface. The platform may include a distal end surface having a corresponding shape (e.g., concave). Alternatively, if at least one non-metallic wear surface has a concave curvature, the platform may include a distal end surface with a convex curvature.

[0099] The flange material is preferably elastic enough to allow compression during use to the extent necessary to achieve a gradual transition of movement between axes. For this implant, for the thumb, the thickness of the flange 105 is preferably in the range of 0.5 mm to 4.0 mm, and more preferably in the range of 1.0 mm to 3.0 mm. The implant can be supplied as a kit, comprising a rod 111 having a proximal portion 122, a distal portion 110, and a series of two or more inserts, each insert fitting into the rod 111 but with a different flange thickness. The flange thickness sets the permissible range of relative movement, and... Figure 6 In the example shown, the angle is 40°. Typically, the flange is preferably configured to provide a movement cone within a range of 30° to 60° around the proximal portion. This allows the surgeon to select the desired movement cone. Therefore, the implant achieves a predictable wear pattern. Furthermore, reducing the movement cone reduces the chance of dislocation. It should be noted that for this type of multiaxial joint, the entire range of motion is actually approximately 80° when considering the sliding movement of the proximal portion on the trapezium. For illustrative purposes, Figure 6 The illustration is based on the proximal portion at rest.

[0100] Furthermore, the proximal surface 101 of the flange 105, with its contoured shape, is configured to mate with the corresponding distal surface 125 of the saddle 122, such that the movement of force between the two motion axes is restricted in a stepwise manner, i.e., the movement between components 110 and 120 is restricted. Therefore, there are no sudden force changes or "clicks" between the two axes. The mating surfaces 101 and 125 provide a large surface area for the contact between components 110 and 120, such as... Figure 5 As shown in Figure 7.

[0101] By inserting a bearing surface 101 between the shafts, forces are distributed in a more controllable, natural, and physiological manner. In one example, relative motion around the hinged connection is limited to approximately 40°, such as... Figure 6 As shown. This range of motion is sufficient for the use of the implant after deployment, but it also helps to ensure that there is no excessive impact force between surfaces and a smooth transition between axes, as shown in Figures 1(a) and 1(b).

[0102] The liner 100 snaps into the element 104, allowing for easy and efficient assembly into the rod 111. Furthermore, the liner snaps into the socket 103, facilitating the acquisition of the mating ball 121 to form an advantageous ball-and-socket joint, due to the elasticity of the material of the insert 100. As shown, the socket 103 can be shaped into a spherical form to accommodate the ball of the ball-and-socket joint.

[0103] The profile of the flange 105 surface 101 is matched with the geometry of the head part 120 to maximize surface contact and thus minimize pad wear.

[0104] Insert 100 is replaceable from within the rod; that is, in the event of excessive wear, it can be removed and another inserted into its position. Insert 100 can be installed and / or removed using suitable tools or tool kits.

[0105] Insert 100 advantageously limits the range of relative rotation in the abduction-adduction and buckling-extension planes. (As in...) Figure 5 and Figure 6 As shown, the saddle 122 has a small degree of freedom to rotate upwards in this view, and there is full surface contact between the saddle 122 and the contour surface 101 when in contact with the surface insert 100. Preferably, the contour surface of the flange tapers radially and distally, and the corresponding mating surface of the saddle tapers radially and proximally.

[0106] exist Figure 5 The lower part of the center view has a smaller convergence surface area, but the same effect and advantages apply. It should be understood that Plug-in 100 improves the impact problem. Of course, Figure 5 The illustration only shows the fit within a single plane, i.e., the plane of this page. For example... Figure 3(d) and 4 As shown, mating surfaces 125 and 101 extend radially around the connecting device (123, 121, 103) in a ring-like manner for approximately 360° of abutment. Flange surface 101 has a predominantly concave shape but a large radius; and the distal surface 125 of the saddle-shaped base 122 has a predominantly convex shape and also a large radius.

[0107] refer to Figure 7(a) and 7(b) The shaded area experiences the greatest material stress between the ball and socket interfaces. In Figure 7(b), the saddle 122 of the proximal portion 120 does not contact the flange 105 of the insert 100. Therefore, all material stress is concentrated at the ball-socket interface (shown as the stress region on the ball 121 in Figure 7(b)). Figure 7(a) shows a portion of the proximal portion 120 that contacts the flange 105 of the insert 100 and faces the proximal end, such as the distal side of the saddle 125. This increased contact area, shown as an additional stress region in Figure 7(a), allows for a wider distribution of material stress. The insert 100 can be thickest at the portion with this increased contact area. This wider and more uniform distribution of stress load on the implant 1 reduces stress concentration at the ball-socket interface (shown at the ball 121) and can extend the lifespan of the implant 1.

[0108] Alternative examples

[0109] It is also envisioned that the implant may have a buffer interface providing a buffer surface, which includes features other than or replacing a flange, and / or this buffer surface is not necessarily on the insert in the distal portion. For example, the proximal portion may have a buffer interface on the distal-facing surface, which engages the distal portion with a large surface area. Such an interface may be a coating with a thickness ranging from 0.5 mm to 3.0 mm, and preferably, for example, from 1.0 mm to 2.0 mm. The interface is preferably made of an elastic material, such as any polymer mentioned above. In this case, it is envisioned that in some examples the distal portion may not have a flange, in which case the proximal portion interface features directly engage the distal portion rod.

[0110] refer to Figure 8(a) and 8(b) The implant 150 is also used for the thumb and includes a distal portion with a bar 151 and a plug 152 to receive a ball 153 of the proximal portion 154. The distal-facing side of the proximal portion 154 has a cushioning interface, namely a coating 157. This interface is provided to achieve at least some of the advantages of the flange of the foregoing embodiments. The coating 157 provides cushioning, reducing the movement cone and providing an increased surface area for distributing forces across the structure.

[0111] The examples in Figures 8(a) and (b) have no flange in the distal portion, only insert 152, to anchor the hinged connection to the rod 151. However, preferably, the distal portion has a flange with a proximal-facing surface, preferably having a profile spaced from the rod at the proximal end, for engagement with the proximal portion 154.

[0112] Figure 2 Alternative configurations for example 7

[0113] Imagine that the distal portion of the implant could integrally incorporate the physical features of the insert. Alternatively, the flange 105 could be provided as a separate item. Furthermore, the insert could alternatively be threaded to engage with the rod, rather than using a snap-fit ​​mechanism.

[0114] A rod with an integral flange can be made of a rigid material, while the connecting ball can be made of a softer material. The flange is associated with the base of the rod and the metacarpal bone.

[0115] The flange can be an integral part of the rod. It preferably has the advantageous feature of having a profiled surface to provide a large surface area for contact with the contact portion.

[0116] It is conceivable that elastic spheres and high-modulus sockets could exist as alternatives.

[0117] In the example above, the profile surface 101 of the flange matches the distal-facing surface 125 of the saddle 122; however, these surfaces can be constructed in other ways. For example, the distal-facing surface 125 of the saddle 122 may not have the convex curvature shown in the figure.

[0118] Traction distance, which is the distance between the two bones after the device is implanted, can be modified by increasing the height of the saddle head, for example... Figure 5 and 6 As shown. The movement cone will not be affected because the flange will have the same geometry. Alternatively, the flange can be thicker or thinner, which will affect the movement cone. In some clinical uses, such as in patients who frequently experience implant dislocation, surgeons may choose to use a flanged insert with a very thick flange during revision surgery to reduce the range of motion and potentially reduce the likelihood of dislocation by increasing the jump distance (the distance the ball must move out of the socket to dislocate).

[0119] It is conceivable that the insert can be joined to the rod without mechanical / physical joining features, and can be joined solely with adhesive bonding.

[0120] Uniaxial implant example

[0121] As noted in the description (Technical Field and Background Art) with reference to Figures 1(c) and 1(d), hip implants may encounter the problem of padding impact around the ball. We also describe an implant with a flange to improve the outcome of hip implants.

[0122] Figure 9 An implant is shown having a spherical neck 201 (only a portion of which is shown) and a socket 202 having a spherical inner socket surface and a flange 203 extending circumferentially around the entrance of the socket and protruding from the socket. The flange 203 is made of an elastic material, such as UHMWPE, PEEK, ceramic, or other materials commonly used in orthopedic implants.

[0123] Flange 203 is part of the liner for the socket 202, and the liner is attached to the remainder of the socket (distal) portion by snap-fit, tapering, or other suitable locking mechanism. The geometry of the flanged liner 203 has an interface surface 204 that mates with the impact member (in this case, the neck 201 below the ball). Flange 203 extends distally from the socket 202 to terminate at each end at the impact surface 204 for impact with the neck 201.

[0124] As described above, the insert is attached to the rest of the socket component by press fit, thread, or snap fit.

[0125] Figure 9Two locations of the neck 201 are shown, illustrating approximately 110° of angular freedom of motion. This arrangement improves impact forces on the socket 202, distributes stress across the interface surface 204, and helps prevent dislocation. Therefore, the flange 203 not only provides a much larger interface / contact surface 204, but is also made of a more resilient material to absorb contact forces.

[0126] As mentioned above, while polymer pads and metal balls are a preferred arrangement, any suitable combination can be used alternatively: metal pads and polymer balls, ceramic pads and polymer balls, or polymer pads and ceramic balls, depending on which is more important, wear mode or biomechanical axis management.

[0127] The profile of a flange can be matched to the geometry of any part of the mating component. For example, in a shoulder implant, the flange can be recessed to best match the relevant geometry of the implant's neck. Similarly, in a hip implant, the flange can be convex to match the geometry of the neck component.

[0128] Depending on the joint and the implant, the distal and proximal portions can be reversed within the entire implant of the joint.

[0129] The present invention is not limited to the described embodiments, but may vary in structure and details.

Claims

1. A bone and joint implant (1), comprising: Proximal portion (120), The distal portion (110), which is used for intramedullary fusion in the bone, A hinged connection device, located between the proximal and distal portions, Its features are, The proximal portion (120) is configured for translational movement on the bone. The implant is configured for multiaxial movement, wherein the proximal portion (120) translates on the bone, and the distal portion (110) rotates about the articulated connection. The implant includes a flange (105) extending radially and around at least some of the hinged coupling, and configured to restrict relative rotational movement of the proximal and distal portions about the hinged coupling. The flange has a profiled surface (101) that matches the adjacent surface (125) of the proximal portion when the portion is hinged to its limit position during use, and the material of the flange (105) is more elastic than the material of the proximal portion it contacts.

2. The bone and joint implant according to claim 1, characterized in that, The contour surface (101) of the flange is annular.

3. The bone and joint implant according to claim 1, characterized in that, The profile surface (101) of the flange (105) tapers radially and distally, and the adjacent surface (125) of the proximal portion tapers radially and proximally.

4. The bone and joint implant according to any one of claims 1 to 3, characterized in that, The flange (105) is included in the insert (100) in the rod (111) of the distal portion (110), the flange extending toward the proximal end of the rod (111) and preventing contact between the proximal portion (120) and the rod (111) during hinge.

5. The osteoarticular implant according to any one of claims 1 to 3, characterized in that, The thickness of the flange is in the range of 0.5 mm to 4.0 mm.

6. The bone and joint implant according to claim 5, characterized in that, The thickness is in the range of 1.0 mm and 3.0 mm.

7. The osteoarticular implant according to any one of claims 1 to 3, characterized in that, The flange is made of polymer material.

8. The osteoarticular implant according to any one of claims 1 to 3, characterized in that, The flange is made of a non-metallic material, and the material is different from that of the adjacent surface.

9. The osteoarticular implant according to any one of claims 1 to 3, characterized in that, The flange is configured to provide a cone of motion of the distal portion around the proximal portion in the range of 30° and 50°.

10. The bone and joint implant according to claim 4, characterized in that, The plug-in includes components of the hinged connection device.

11. The bone and joint implant according to claim 10, characterized in that, The hinged connection device is a ball-and-socket connection device and the plug (100) includes the socket of the ball-and-socket connection device.

12. The bone and joint implant according to claim 4, characterized in that, The plug-in includes a locking feature (104) for snapping into the rod (111).

13. The bone and joint implant according to claim 12, characterized in that, The locking feature is the distal annular edge (104) of the plug (100).

14. The bone and joint implant according to any one of claims 1 to 3, characterized in that, The implant is for a first carpal joint in a mammal, and the proximal portion is configured for translational movement on the trapezium, and the distal portion is configured for intramedullary engagement with the end of the first metacarpal bone.

15. The bone and joint implant according to any one of claims 1 to 3, characterized in that, The profile surface (101) of the flange is an annular non-metallic wear surface that prevents contact between the pedestal (122) of the proximal portion (120) and the rod (111) of the distal portion (110) during hinge.

16. The bone and joint implant according to claim 15, characterized in that, The annular non-metallic wear surface includes a concave curvature.

17. The bone and joint implant according to claim 15, characterized in that, The proximal portion of the pedestal (122) includes a distal end surface with a convex curvature.

18. The bone and joint implant according to any one of claims 1 to 3, characterized in that, The implant includes a distal non-metallic wear surface shaped into a spherical form.

19. The bone and joint implant according to any one of claims 1 to 3, characterized in that, The flange (105) is an integral part of an integral non-metallic wear component insert (100), the insert being configured to be inserted into the rod (111) of the distal portion (110), the insert having a proximal non-metallic wear surface for abutting the proximal portion (120) at a limit hinge position and a distal non-metallic wear surface for engaging with the surface of the hinged connection component (121).

20. The bone and joint implant according to claim 19, characterized in that, The integral non-metallic wear member is an insert (100) housed in the proximal end surface of the rod (111), and the insert includes a proximal portion extending proximal to the proximal end surface of the rod, wherein the proximal portion is a flange (105) of the insert, and the flange includes a proximal non-metallic wear surface.

21. The bone and joint implant according to claim 19, characterized in that, The hinged connection device is a ball-and-socket connection device, and the plug (100) forms the socket of the ball-and-socket connection device.

22. An insert (100) for a joint implant (1), the joint implant including a proximal portion (120), a distal portion (110), and a hinged connection between the proximal and distal portions, wherein the insert (100) is configured to engage the distal portion and includes a flange (105) configured to limit relative rotational movement about the hinged connection, and wherein: The material of the flange (105) is more elastic than the material of the proximal portion (120) it contacts. The flange has a profile surface (101) that matches the adjacent surface (125) of the proximal portion when the portion is hinged to its limit position during use, and the profile surface (101) of the flange is annular.

23. The plug-in according to claim 22, characterized in that, The profile surface (101) of the flange (105) tapers radially and distally, and the proximal portion matches and abuts the surface radially and proximally.

24. The plug-in according to claim 22 or 23, characterized in that, The insert (100) is configured to be inserted into the intramedullary rod (111) of the distal portion (110), the flange extending proximally toward the intramedullary rod (111).

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