CN116531149A - Radius bone prosthesis - Google Patents

Abstract

The invention relates to a radius head prosthesis, which comprises a liner, a cup body, a lining, a radius handle and a locking ring, wherein the liner is connected with the top side of the cup body, the liner is provided with a joint surface, the cup body is provided with an inner cavity, the inner cavity is provided with an opening facing the bottom side of the cup body, the lining is arranged in the inner cavity and matched with the top side of the inner cavity, one end of the radius handle is arranged in the inner cavity and is in spherical contact with the lining, the locking ring is sleeved on the radius handle and is connected with the side wall of the inner cavity, and the locking ring is used for limiting the axial movement of the radius handle. According to the radius bone prosthesis, the locking ring limits the axial movement of the radius handle, and the radius handle and the lining keep in spherical contact so as to adapt to the rotation and the varus-valgus actions between the corresponding radius bone and the humerus of a human body, the lining can reduce the abrasion between the radius handle and the cup body, the matching degree is improved, and the probability of looseness of the radius handle relative to the cup body is reduced.

Description

Radius bone prosthesis

Technical Field

The invention relates to the technical field of orthopedics, in particular to a radius head prosthesis.

Background

The articular surface between the radius and the humerus is subjected to 60% of the contact force of the elbow joint and provides stability to the elbow joint. Radius fracture is the most common fracture of adult elbow, accounts for about 32% of elbow joint fracture, and for irreparable radius fracture, radius head prosthesis replacement is an effective treatment method, and compared with simple radius head excision and incision reduction internal fixation, the occurrence of elbow joint instability can be effectively reduced.

However, the existing radius head prosthesis has the problem of poor matching with the small head of the humerus, and the radius head prosthesis is easy to loose.

Disclosure of Invention

Based on the above, a radius head prosthesis is provided to solve the problem that the matching degree is poor and looseness is easy to occur.

The invention provides a radius head prosthesis, which comprises a liner, a cup body, a lining, a radius handle and a locking ring, wherein the liner is connected with the top side of the cup body, the liner is provided with a joint surface, the cup body is provided with an inner cavity, the inner cavity is provided with an opening facing the bottom side of the cup body, the lining is arranged in the inner cavity and matched with the inner cavity, one end of the radius handle is arranged in the inner cavity and keeps spherical contact with the lining, the locking ring is sleeved on the radius handle and connected with the side wall of the inner cavity, and the locking ring is used for limiting the axial movement of the radius handle.

In one embodiment, the top side of the cup is provided with a recess, and the liner is secured within the recess.

In one embodiment, the outer side of the cup has an outer spherical surface for forming an axle articulation surface.

In one embodiment, the top side of the inner cavity has an inner spherical surface, and the side of the inner liner facing away from the radius handle has a convex spherical surface, and the inner spherical surface is used for being matched with the convex spherical surface.

In one embodiment, the side wall of the inner cavity is formed with a first step portion, the first step portion is adjacent to the edge of the inner sphere, and the first step portion is used for being matched with the inner liner, so that the inner liner is limited in the inner cavity.

In one embodiment, the first step portion has a first wall surface, a second wall surface and a first limiting surface, the first wall surface is adjacent to the edge of the inner sphere, the surrounding radius of the first wall surface is larger than that of the second wall surface, the first limiting surface is connected between the first wall surface and the second wall surface, the inner liner comprises a first matching surface, a second matching surface and a first abutting surface, the first abutting surface is connected between the first matching surface and the second matching surface, the first matching surface is in clearance fit with the first wall surface, the second matching surface is in clearance fit with the second wall surface, and the first abutting surface is in abutting connection with the first limiting surface.

In one embodiment, a second mating surface is further disposed on a side of the first abutting surface away from the first mating surface, and the second mating surface is configured to be in clearance fit with the second wall surface.

In one embodiment, one end of the radius shank has a ball head, and the side of the inner liner facing the radius shank has a concave spherical surface for contacting the ball head spherical surface to form a ball-and-socket joint.

In one embodiment, the radius handle further comprises a handle body extending along the axial direction of the radius handle, one end of the handle body is connected with the ball head, the other end of the handle body extends out of the inner cavity, a positioning ring is arranged around the handle body, and one side, facing away from the ball head, of the positioning ring is used for being in contact with a radius osteotomy surface.

In one embodiment, the diameter of the retaining ring decreases progressively in a direction approaching the ball head.

In one embodiment, the locking ring is provided with an opening or the locking ring is resilient such that the locking ring has a radially expanded state and a restored state, the diameter of the bulb of the radius shank being smaller or equal to the inner diameter of the locking ring in the radially expanded state and larger than the inner diameter of the locking ring in the restored state.

In one embodiment, the locking ring has an inner spherical surface and an inner inclined surface arranged along an axial direction thereof, the inner spherical surface is used for being contacted with the ball head spherical surface of the radius handle, and an inner diameter of the locking ring at the inner inclined surface gradually becomes larger along a direction facing to an inner cavity opening so as to guide the ball head of the radius handle to pass through the locking ring.

In one embodiment, a support ring is disposed between the locking ring and the cup, the support ring being configured to space the locking ring from a sidewall of the lumen.

In one embodiment, the side wall of the inner cavity is formed with a second step portion, the second step portion is provided with a first inner wall surface, a second inner wall surface and a second limiting surface, the surrounding radius of the first inner wall surface is larger than that of the second inner wall surface, the second limiting surface is connected between the first inner wall surface and the second inner wall surface, the outer side surface of the supporting ring comprises a first columnar surface, a second columnar surface and an outer step surface, the outer step surface is connected between the first columnar surface and the second columnar surface, the first columnar surface is used for being in clearance fit with the first inner wall surface, the second columnar surface is used for being in clearance fit with the second inner wall surface, and the outer step surface is used for being in butt joint with the second limiting surface so as to limit the supporting ring in the inner cavity.

In one embodiment, the locking ring has a first outer ring, a second outer ring, and a second abutment surface formed between the first outer ring and the second outer ring, and the inner side surface of the supporting ring includes a first inner surface for clearance fit with the first outer ring, a second inner surface for clearance fit with the second outer ring, and an inner step surface for abutment with the second abutment surface to limit the axial position of the locking ring.

In one embodiment, the side wall of the inner cavity is provided with a first conical surface, the first conical surface is located on the top side of the second step part, the diameter of the cross-section circle of the first conical surface gradually increases in the direction away from the bottom side of the cup body, and when the support ring is matched with the cup body, the first conical surface and the first inner surface are in smooth transition.

In one embodiment, a second conical surface is formed in the inner cavity near the opening, and the diameter of the cross-sectional circle of the second conical surface gradually increases in the direction near the bottom side of the cup body.

According to the radius bone prosthesis, the locking ring limits the axial movement of the radius handle, and the radius handle and the lining keep in spherical contact so as to adapt to the rotation and the varus-valgus actions between the corresponding radius bone and the humerus of a human body, the lining can reduce the abrasion between the radius handle and the cup body, the matching degree is improved, and the probability of looseness of the radius handle relative to the cup body is reduced.

Drawings

In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other embodiments of the drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic cross-sectional view of a radius head prosthesis according to an embodiment of the present invention;

FIG. 2 is a schematic view of the radial shaft of the radial prosthesis rotated to another position relative to the cup;

FIG. 3 is a schematic view showing a connection structure of a liner and a cup of a radius bone prosthesis according to an embodiment;

FIG. 4 is a schematic view of another embodiment of a connection between a liner and a cup of a radial head prosthesis;

FIG. 5 is a schematic view of the cup of the radial prosthesis according to one embodiment;

FIG. 6 is an enlarged partial schematic view of the portion A of the cup of the radial prosthesis shown in FIG. 5;

FIG. 7 is an enlarged partial schematic view of a portion B of the cup of the radial prosthesis shown in FIG. 5;

FIG. 8 is a schematic view of the structure of a liner of a radial prosthesis according to one embodiment;

FIG. 9 is a schematic view of the structure of a radial shaft of a radial prosthesis according to one embodiment;

FIG. 10 is a schematic view of the structure of a locking ring of a radial prosthesis according to one embodiment;

FIG. 11 is a schematic view of the shape of the opening of the locking ring of the radial prosthesis of an embodiment, wherein FIG. 11 (a) shows the opening of the locking ring extending vertically through the locking ring, FIG. 11 (b) shows the opening of the locking ring extending obliquely through the locking ring, FIG. 11 (c) shows the opening of the locking ring being V-shaped and extending obliquely through the locking ring, and FIG. 11 (d) shows the opening of the locking ring extending through the locking ring and being provided with a chamfer;

fig. 12 is a schematic view of the structure of a supporting ring of a radius bone prosthesis according to an embodiment.

Detailed Description

In order that the above objects, features and advantages of the invention will be readily understood, a more particular description of the invention will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The present invention may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the invention, whereby the invention is not limited to the specific embodiments disclosed below.

It will be understood that when an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present.

The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like are used for illustration purposes only and are not meant to be the only embodiment.

It is to be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counter-clockwise," "axial," "radial," "circumferential," and the like are directional or positional relationships as indicated based on the drawings, merely to facilitate describing the invention and to simplify the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the invention.

Referring to fig. 1 and 2, a radius head prosthesis according to an embodiment of the present invention may be used for radius head replacement to replace a damaged radius head of a patient when the radius of the patient is fractured or damaged, thereby restoring the function of an elbow joint.

Specifically, the radius bone prosthesis comprises a liner 1, a cup 2, a liner 3, a radius stem 4 and a locking ring 5.

The liner 1 is connected to the top side of the cup 2, the top side of the cup 2 being the side facing away from the radius when the cup 2 is fixed to the radius. In some embodiments, the top side of the cup 2 is provided with a recess 21, and the liner 1 is secured within the recess 21. As shown in connection with fig. 3 and 4, the liner 1 has a joint surface 11 and an outer surface 12, the joint surface 11 is used to form a ball joint surface with the small humerus head (not shown), and the outer surface 12 of the liner 1 is matched with the groove 21 of the cup 2, so that the liner 1 is stably connected with the cup 2.

It should be noted that, taper connection may be adopted between the liner 1 and the cup body 2, or slot connection may be adopted. For example, as shown in fig. 3, the outer surface of the liner 1 and the side wall of the groove 21 are tapered, and the outer surface 12 of the liner 1 is in tapered connection with the groove 21 of the cup body 2, wherein the tapered connection means that the surface of the outer surface 12 connected with the groove 21 is not parallel to the axial direction, but forms a cone shape. Preferably, the taper angle of the outer surface 12 of the liner 1 is 5 ° to 35 °. As another example, as shown in fig. 4, the outer surface 12 of the gasket 1 is formed with a catching protrusion 12a, and accordingly, the sidewall of the groove 21 is formed with a catching groove 21a that is engaged with the catching protrusion 12a, so that when the gasket 1 is engaged with the groove 21 of the cup body 2, the connection stability between the gasket 1 and the cup body 2 is enhanced by the engagement between the catching protrusion 12a and the catching groove 21 a.

In other embodiments, the liner 1 and the cup body 2 may be connected together by welding or glue, and the connection manner between the liner 1 and the cup body 2 is not limited herein.

As shown in connection with fig. 5, the cup 2 has a spherical crown shape, the cup 2 having an inner cavity extending through the bottom side of the cup 2, in particular, the inner cavity having an opening towards the bottom side of the cup 2. The liner 3, the radial stem 4 and the locking ring 5 may be fitted from the underside of the cup 2 to the inner cavity through the opening. In this embodiment, the bottom side of the cup 2 refers to the side facing the radius when the cup 2 is fixed to the radius (i.e., the lower side in fig. 5).

Liner 3 mates with the top side of the interior cavity of cup 2 so that liner 3 may be fitted with radial stem 4 when liner 3 mates with cup 2. Specifically, one end of the radius handle 4 is disposed in the inner cavity of the cup body 2 and keeps in spherical contact with the inner liner 3, so that the radius handle 4 rotates and swings relative to the cup body 2 to adapt to the rotation and the varus-valgus actions between the radius bone and the humerus corresponding to the human body. Wherein, inside lining 3 can play good abrasionproof effect between radius handle 4 and cup 2 to reduce the wearing and tearing between radius handle 4 and cup 2, promote the matching degree, reduce the probability that radius handle 4 appears not hard up relative cup 2.

In this embodiment, the locking ring 5 is sleeved on the radius handle 4 and connected with the side wall of the inner cavity, so as to limit the axial movement of the radius handle 4 and improve the stability of the spherical contact between the radius handle 4 and the inner liner 3.

It should be noted that, the radius handle 4 is matched with the medullary cavity (not shown) of the radius of the human body, and the radius handle 4 can rotate relative to the cup 2, so that the rotation and the varus-valgus actions between the corresponding radius and the humerus of the human body can be adapted.

In some embodiments, a support ring 6 is provided between the locking ring 5 and the cup 2, the support ring 6 being in an interference fit with the cup 2 such that the locking ring 5 is clamped between the support ring 6 and the radial stem 4. By adopting the structural arrangement, the supporting ring 6 can separate the locking ring 5 from the side wall of the inner cavity of the cup body 2, so that the abrasion and abnormal sound caused by the direct contact between the locking ring 5 and the cup body 2 are avoided. In addition, as contact abrasion does not occur between the locking ring 5 and the cup body 2, abrasive dust does not occur, so that the abrasion probability of the locking ring 5 is reduced, the locking ring 5 is beneficial to maintaining the stable locking effect on the radius handle 4, the spherical contact stability between the radius handle 4 and the lining 3 is improved, and the probability of looseness of the radius handle 4 is reduced.

The lining 1 and the lining 3 can be made of polyformaldehyde, polyvinylidene fluoride or nylon 62, so that the friction parts contacted with each other have good self-lubricating effect, and the abrasion of structural parts is reduced.

The locking ring 5 is made of ultra-high molecular weight polyethylene (UHMWPE for short) to improve the wear resistance of the locking ring 5.

The material of the support ring 6 is ultra-high molecular weight polyethylene, so that the support ring 6 is not easy to be worn.

The cup body 2 and the radius handle 4 are both made of metal materials so as to provide enough structural strength, thereby being capable of bearing higher load and improving the stability of the joint surface between the radius bone prosthesis and the humerus. In some embodiments, the cup body 2 is made of a metal material such as medical stainless steel, titanium alloy or cobalt chromium molybdenum alloy, and correspondingly, the radius handle 4 can also be made of a metal material such as medical stainless steel, titanium alloy or cobalt chromium molybdenum alloy.

Referring to fig. 5, the cup body 2 has an outer spherical surface 22 and an inner spherical surface 23, the recess 21 is formed in the outer spherical surface 22, and the inner spherical surface 23 forms part of the side wall of the inner cavity of the cup body 2 and is located at the top side of the inner cavity. The outer sphere 22 is used to form an axle articular surface to mate with a radial notch (not shown) of the ulna. The inner sphere 23 is matched with the inner liner 3, so that the inner liner 3 is matched with the cup body 2 stably. In embodiments where the top side of the cavity has an inner spherical surface 23, the side of the liner 3 facing away from the radial stem 4 has a convex spherical surface 31, the inner spherical surface 23 being adapted to mate with the convex spherical surface 31, e.g., the convex spherical surface 31 is in clearance fit with the inner spherical surface 23 of the cup 2. In other embodiments, an interference fit may also be employed between the convex spherical surface 31 and the inner spherical surface 23.

The convex spherical surface 31 may be connected to the inner spherical surface 23 by glue, so that the liner 3 is connected to the cup body 2.

In other embodiments, the liner 3 may be snap fit to the cup 2. Specifically, the sidewall of the inner cavity of the cup body 2 is formed with a first step portion 24, and the first step portion 24 is used for being matched with the liner 3, limiting the liner 3 in the inner cavity of the cup body 2, and enabling the liner 3 to abut against the inner spherical surface 23. In this embodiment, the first step 24 may be contiguous with the edge of the inner sphere 23. Further, as shown in fig. 6, the first step portion 24 has a first wall surface 241, a second wall surface 242, and a first stopper surface 243. The first wall 241 adjoins the edge of the inner sphere 23, the first wall 241 having a larger surrounding radius than the second wall 242, i.e. the first wall 241 has a larger cross-sectional area than the second wall 242. The first limiting surface 243 is connected between the first wall surface 241 and the second wall surface 242, and the first limiting surface 243 is used for limiting the liner 3 mounted to the inner cavity, so that the liner 3 is not easy to move or fall off in the inner cavity. The radius of the first wall 241 is the radius of the cylinder surrounded by the first wall 241, and the radius of the second wall 242 is the radius of the cylinder surrounded by the second wall 242.

As shown in connection with fig. 8, the liner 3 has opposite outer and inner surfaces. The outer surface of the liner 3 is matched with the inner cavity of the cup body 2 so that the liner 3 is stably limited in the inner cavity by the first step part 24, and the liner 3 is not easy to fall off from the cup body 2.

Specifically, the outer surface of the liner 3 includes a first mating surface 32 and a first abutment surface 33 that are sequentially connected to the convex spherical surface 31. When the liner 3 is matched with the cup body 2, the first matching surface 32 is in clearance fit with the first wall surface 241 of the first step part 24, the first abutting surface 33 abuts against the first limiting surface 243 of the first step part 24, and the liner 3 is ensured to be fixed with the cup body 2, so that the liner is not easy to separate from the cup body 2. In other embodiments, the first step 24 may be in interference fit with the liner 3, and the manner of fitting the first step 24 with the liner 3 is not limited.

In some embodiments, a second mating surface 34 is further provided on a side of the first abutment surface 33 remote from the first mating surface 32, the second mating surface 34 being in clearance fit with the second wall surface 242 of the first step 24. By adopting the structure, the requirement of stable matching between the lining 3 and the cup body 2 can be met, and meanwhile, the inner surface of the lining 3 can be extended as much as possible through the clearance matching between the second matching surface 34 and the second wall surface 242, so that a large enough spherical contact area is formed between the inner surface of the lining 3 and the radius handle 4.

As shown in fig. 8 and 9, the inner surface of the liner 3 includes a concave spherical surface 35, and the concave spherical surface 35 is used to form spherical contact with the radial stem 4, so as to facilitate flexible rotation of the radial stem 4 relative to the cup 2. Specifically, one end of the radius shaft 4 has a ball head 41, and when the radius shaft 4 is fitted with the inner liner 3, the side of the inner liner 3 provided with the concave spherical surface 35 is faced to the radius shaft 4 so that the concave spherical surface 35 is fitted with the ball head 41. It should be noted that, the concave spherical surface 35 and the ball head 41 are in spherical contact to form a ball-and-socket joint, so that the spherical contact between the radius handle 4 and the inner liner 3 is realized, and the requirements of rotation and varus-valgus movement of the radius handle 4 relative to the inner liner 3 are met.

Further, the radius shaft 4 further includes a positioning ring 42 and a shaft 43, the shaft 43 extends along the axial direction of the radius shaft 4 (which can be understood as the length direction of the radius shaft 4), one end of the shaft 43 is connected with the ball head 41, and the other end of the shaft 43 extends out of the inner cavity of the cup body 2.

The positioning ring 42 is disposed around the shank 43, and a contact surface 42a is formed on a side of the positioning ring 42 facing away from the ball head 41, and when the shank 43 is matched with a medullary cavity (not shown) of a radius, the contact surface 42a of the positioning ring 42 contacts with the radius osteotomy surface, so that the implantation depth of the radius shank 4 is positioned by using the positioning ring 42, and the radius shank 4 is stably connected with the medullary cavity of the radius.

It should be noted that the shape of the contact surface 42a may be determined according to the size of the radius osteotomy surface to ensure coverage of the radius bone prosthesis at the radius osteotomy surface. The stem 43 may be bone cement or non-bone cement to match the intramedullary canal of the radius (not shown).

Further, the positioning ring 42 is designed to be an outer conical surface, so that the movement range of the radius handle 4 can be increased. Specifically, as shown in fig. 2 and 9, the circumferential surface of the positioning ring 42 is tapered, and the diameter of the positioning ring 42 gradually decreases in the direction approaching the ball head 41, so that the circumferential surface of the positioning ring 42 is tapered while maintaining the size of the contact surface 42a of the positioning ring 42, and the radial handle 4 can be rotated by a larger angle with respect to the cup 2 than the circumferential surface of the positioning ring 42 is cylindrical.

The support ring 6 can limit removal of the locking ring 5 from the bottom side of the cup 2 when the locking ring 5 and the support ring 6 are fitted to the interior cavity of the cup 2.

Specifically, as shown in fig. 10, the lock ring 5 has a first outer ring 51, a second outer ring 52, and a second abutment surface 53 formed between the first outer ring 51 and the second outer ring 52. As shown in connection with fig. 12, the inner side surface of the support ring 6 includes a first inner surface 61, a second inner surface 62, and an inner step surface 63, the inner step surface 63 being formed between the first inner surface 61 and the second inner surface 62.

When the support ring 6 and the locking ring 5 are assembled to the inner cavity of the cup 2, the first inner surface 61 is in clearance fit with the first outer ring 51 of the locking ring 5, the second inner surface 62 is in clearance fit with the second outer ring 52 of the locking ring 5, and the inner step surface 63 abuts against the second abutment surface 53 of the locking ring 5 to limit the axial position of the locking ring 5 relative to the support ring 6 and further to prevent the locking ring 5 from being pulled out of the inner cavity of the cup 2.

It should be noted that the support ring 6 may be annular, and the first inner surface 61 and the second inner surface 62 may be tapered surfaces, for example, tapered surfaces. In other embodiments, the support ring 6 may be rectangular ring-shaped. The shape of the support ring 6 and the shape of its corresponding inner surface are not limited herein.

As shown in connection with fig. 10, the locking ring 5 is provided with an opening 54, the opening 54 cuts off the locking ring 5 so that the locking ring 5 is a non-closed ring, in this way, the opening 54 is arranged so that the locking ring 5 can expand when being subjected to a radially outward force and can be compressed when being subjected to a radially inward force, thereby facilitating the assembly of the ball head 41 and the locking ring 5 into the inner cavity of the cup body 2 so as to ensure the locking strength of the locking ring 5 to the radius handle 4. The width of the opening 54 is 2mm-6mm, preferably 4mm.

In other embodiments, the locking ring 5 is made of an elastic material, making the locking ring 5 itself elastic, whatever the way the locking ring 5 has, as long as it has a radially expanded state and a restored state. As long as the diameter of the ball 41 is smaller than or equal to the inner diameter of the locking ring 5 in the radially expanded state and larger than the inner diameter of the locking ring 5 in the restored state, the locking ring 5 can pass the ball 41 in the radially expanded state and can restrict the axial movement of the radius shank 4 in the restored state.

The locking ring 5 is provided with an inner spherical surface 55 and an inner inclined surface 56 which are axially arranged, wherein the inner spherical surface 55 is in spherical contact with the ball head 41 and is used for realizing the varus-valgus movement of the radius handle 4; the inner inclined surface 56 is used for guiding the ball 41 to pass through the locking ring 5, so that the ball 41 is locked in the inner cavity of the cup body 2 under the abutting of the inner spherical surface 55 to maintain the spherical contact between the ball 41 and the lining 3. At the same time, the diameter of the locking ring 5 at the inner inclined surface 56 gradually increases in the direction of opening the inner cavity of the cup body 2, namely, a flared mouth opening in the radial direction is formed, so that the radial handle 4 can be allowed to swing in a certain angle, and the varus-valgus movement of the radial handle 4 is realized.

As shown in connection with fig. 11, the form of the opening 54 of the locking ring 5 has several possible groups. Specifically, as shown in fig. 11 (a), the opening 54 of the lock ring 5 vertically penetrates the lock ring 5; as shown in fig. 11 (b), the opening 54 of the locking ring 5 is inclined through the locking ring 5; as shown in fig. 11 (c), the opening 54 of the locking ring 5 is V-shaped and is inclined through the locking ring 5; as shown in fig. 11 (d), the opening 54 of the lock ring 5 penetrates the lock ring 5 and is provided with a chamfer. The shape of the opening 54 of the locking ring 5 is not limited herein, for example, in some embodiments, the opening 54 extends in a W-shape or wavy line.

Referring again to fig. 5, the sidewall of the inner cavity of the cup body 2 is formed with a second stepped portion 26, and the second stepped portion 26 is located on a side of the first stepped portion 24 farther from the liner 1, specifically, the second stepped portion 26 is located closer to the bottom side of the cup body 2 than the first stepped portion 24.

The second step 26 is used to cooperate with the support ring 6 to limit the support ring 6 to the inner cavity of the cup 2. Specifically, as shown in fig. 7, the second step portion 26 has a first inner wall surface 261, a second inner wall surface 262, and a second stopper surface 263. The first inner wall surface 261 has a larger surrounding radius than the second inner wall surface 262, and the second inner wall surface 262 is closer to the bottom side of the cup body 2 than the first inner wall surface 261. The second limiting surface 263 is connected between the first inner wall surface 261 and the second inner wall surface 262 to limit the support ring 6 mounted to the inner cavity so that the liner 3 is not easily moved or fallen off in the inner cavity. The radius of the first inner wall surface 261 is the radius of the cylinder surrounded by the first inner wall surface 261, and the radius of the second inner wall surface 262 is the radius of the cylinder surrounded by the second inner wall surface 262.

As shown in connection with fig. 12, the outer side surface of the support ring 6 is fitted with the second step 26. Specifically, the outer side surface of the support ring 6 includes a first columnar surface 64, a second columnar surface 65, and an outer stepped surface 66, the outer stepped surface 66 being connected between the first columnar surface 64 and the second columnar surface 65. When the support ring 6 is assembled to the inner cavity of the cup body 2, the first columnar surface 64 is in clearance fit with the first inner wall surface 261 of the second step portion 26, the second columnar surface 65 is in clearance fit with the second inner wall surface 262 of the second step portion 26, and the outer step surface 66 abuts against the second limiting surface 263 of the second step portion 26, so that the support ring 6 is limited in the inner cavity of the cup body 2, namely, the support ring 6 is limited to move out of the inner cavity of the cup body 2, and then the effect of preventing the support ring 6 from being separated from the cup body 2 is achieved.

In other embodiments, each wall surface of the second step portion 26 may form an interference fit with the support ring 6, and the manner of fitting the second step portion 26 and the support ring 6 is not limited, so long as the second step portion 26 formed on the sidewall of the inner cavity can be fitted with the support ring 6 to limit the support ring 6 from moving out of the inner cavity when the support ring 6 is assembled to the inner cavity of the cup body 2.

The first columnar surface 64 and the second columnar surface 65 may be regular columnar surfaces having uniform cross sections at respective positions, or irregular columnar surfaces having non-uniform cross sections at respective positions. For example, in other embodiments, the first cylindrical surface 64 and the second cylindrical surface 65 may be cylindrical surfaces, or may be non-cylindrical surfaces, such as pyramid cylindrical surfaces or prismatic cylindrical surfaces.

Referring again to fig. 5, in some embodiments, the sidewall of the interior cavity of the cup 2 has a first conical surface 25, the first conical surface 25 being located on the top side of the second step 26. The diameter of the cross-sectional circle of the first conical surface 25 gradually increases in a direction away from the bottom side of the cup 2. When the support ring 6 is mated with the cup 2, the first conical surface 25 smoothly transitions with the first conical inner surface 61 of the support ring 6 to together form a larger inner conical surface, thereby allowing a wide range of guiding movement of the locking ring 5, ultimately bringing the locking ring 5 into the locked position.

The radius bone prosthesis is convenient to assemble, the connection between the radius handle 4 and the cup body 2 does not need special tools, and the connection is simple and reliable. Specifically, when the radial stem 4 is installed, the ball 41 pushes the locking ring 5 to move along the conical surface of the first conical surface 25 until the locking ring 5 contacts the inner liner 3, the ball 41 continues to act on the inner inclined surface 56 of the locking ring 5 to prop open the opening 54 until the maximum vertical axial section of the ball 41 passes through the locking ring 5 and makes the ball 41 contact the concave spherical surface 35 of the inner liner 3, the radial stem 4 stops being pushed to the side of the inner liner 3, at the moment, the locking ring 5 loses the support of the ball 41 and moves downwards to contact the supporting ring 6, the opening 54 returns to the initial opening 54 size, the radial stem 4 is axially locked, and the radial stem 4 is prevented from moving downwards along the axial direction to be separated from the cup body 2.

In the embodiment in which the first step 24 and the second step 26 are formed on the side wall of the inner cavity, the first conical surface 25 is located between the first step 24 and the second step 26.

A second conical surface 27 is formed in the inner cavity near the opening. Specifically, the diameter of the cross-sectional circle of the second conical surface 27 gradually increases in the direction approaching the bottom side of the cup body 2, that is, the diameter of the cross-sectional circle of the second conical surface 27 increases as approaching the bottom side of the cup body 2. The second conical surface 27 is used for meeting the requirement of large-angle inward and outward turning movement of the radius handle 4 and avoiding interference between the radius handle 4 and the cup body 2.

It should be noted that the radius head prosthesis may be manufactured in a variety of sizes to accommodate the needs of different patients. In addition, the radius head prosthesis according to the embodiment of the present invention may be used for the replacement of the radius head alone or as one of the components for the replacement of the whole elbow joint, and is not limited herein as to the specific application scenario of the radius head prosthesis.

It should be noted that, in the embodiments of the present invention, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or an implicit indication of the number of technical features being indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.

In the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally formed; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present invention, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium.

The technical features of the above embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The foregoing examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims (16)

1. The utility model provides a radius head prosthesis, its characterized in that includes liner, cup, inside lining, radius handle and locking ring, the liner with the topside of cup is connected, the liner has the joint face, the cup has the inner chamber, the inner chamber has the orientation the opening of the bottom side of cup, the inside lining set up in the inner chamber and with the topside phase-match of inner chamber, the one end of radius handle set up in the inner chamber and with the inside lining keeps the sphere to contact, the locking ring cover is located the radius handle and is connected with the lateral wall of inner chamber, the locking ring is used for restricting the axial motion of radius handle.

2. The radius bone prosthesis of claim 1, wherein the top side of the cup is provided with a recess, the liner being secured within the recess.

3. The radius bone prosthesis of claim 1, wherein the outer side of the cup has an outer spherical surface for forming an axle articulation surface.

4. The radius bone prosthesis of claim 1, wherein the top side of the inner cavity has an inner spherical surface, and the side of the inner liner facing away from the radius shank has a convex spherical surface, the inner spherical surface for mating with the convex spherical surface.

5. The radius bone prosthesis of claim 4, wherein a sidewall of the inner cavity is formed with a first step, the first step abutting an edge of the inner sphere, the first step for mating with the liner such that the liner is confined within the inner cavity.

6. The radius bone prosthesis of claim 5, wherein the first stepped portion has a first wall surface, a second wall surface, and a first stop surface, the first wall surface being adjacent to an edge of the inner spherical surface, the first wall surface having a surrounding radius greater than a surrounding radius of the second wall surface, the first stop surface being connected between the first wall surface and the second wall surface, the liner including a first mating surface, a second mating surface, and a first abutment surface connected in sequence with the convex spherical surface, the first abutment surface being connected between the first mating surface and the second mating surface, the first mating surface being for clearance fit with the first wall surface, the second mating surface being for clearance fit with the second wall surface, the first abutment surface being for abutment with the first stop surface.

7. The radius bone prosthesis of claim 1, wherein one end of the radius stem has a ball head, and the side of the liner facing the radius stem has a concave spherical surface for contacting the ball head spherical surface to form a ball and socket joint.

8. The radius head prosthesis of claim 7, wherein the radius shaft further comprises a shaft extending axially therefrom, one end of the shaft being connected to the ball head, the other end of the shaft extending beyond the inner cavity, a retaining ring being provided around the shaft, the retaining ring being disposed on a side of the shaft facing away from the ball head for contact with a radius osteotomy surface.

9. The radius bone prosthesis of claim 8, wherein the diameter of the retaining ring gradually decreases in a direction approaching the ball head.

10. The radius head prosthesis of claim 7, wherein the locking ring is provided with an opening or the locking ring is resilient such that the locking ring has a radially expanded state and a restored state, the diameter of the bulb of the radius stem being smaller or equal to the inner diameter of the locking ring in the radially expanded state and larger than the inner diameter of the locking ring in the restored state.

11. The radius bone prosthesis according to claim 10, wherein the locking ring has an inner spherical surface and an inner inclined surface arranged along an axial direction thereof, the inner spherical surface for being in contact with a ball spherical surface of the radius shank, an inner diameter of the locking ring at the inner inclined surface being gradually enlarged in a direction toward an opening of the inner cavity to guide the ball of the radius shank through the locking ring.

12. The radius bone prosthesis of claim 1, wherein a support ring is disposed between the locking ring and the cup, the support ring configured to space the locking ring from a sidewall of the inner cavity.

13. The radius bone prosthesis of claim 12, wherein the sidewall of the inner cavity is formed with a second step portion having a first inner wall surface, a second inner wall surface, and a second stop surface, the first inner wall surface having a larger surrounding radius than the second inner wall surface, the second stop surface being connected between the first inner wall surface and the second inner wall surface, the outer surface of the support ring including a first cylindrical surface for clearance fit with the first cylindrical surface, a second cylindrical surface for clearance fit with the second inner wall surface, and an outer step surface for abutment with the second stop surface to limit the support ring in the inner cavity.

14. The radius bone prosthesis of claim 13, wherein the locking ring has a first outer ring, a second outer ring, and a second abutment surface formed between the first outer ring and the second outer ring, the inner side surface of the support ring including a first inner surface for clearance fit with the first outer ring, a second inner surface for clearance fit with the second outer ring, and an inner step surface for abutment with the second abutment surface to limit the axial position of the locking ring.

15. The radius bone prosthesis of claim 14, wherein the sidewall of the inner cavity has a first conical surface on a top side of the second stepped portion, the first conical surface having a cross-sectional circle with a diameter that gradually increases in a direction away from the bottom side of the cup, the first conical surface smoothly transitioning with the first inner surface when the support ring is mated with the cup.

16. The radius bone prosthesis according to claim 1, wherein a second conical surface is formed in the inner cavity near the opening, and a diameter of a cross-sectional circle of the second conical surface gradually increases in a direction near the bottom side of the cup body.