Pad for acetabular bone revision and reconstruction and fixing structure for pad and acetabular cup prosthesis

The present disclosure relates to the field of medical instruments, in particular to a pad for acetabular bone revision and reconstruction and a fixing structure for a pad and an acetabular cup prosthesis. The pad is located between an acetabular cup prosthesis and the acetabular bone, and is connected to the acetabular cup prosthesis and the acetabular bone respectively. The pad includes a first component and a second component which has the same or different radius and shape as or from the radius and shape of the first component; the first component is movably connected with the second component; and the shape of the connected first component and second component is matched with a defective part of the acetabular bone.

CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from Chinese Patent Application No. 202111329391.8, filed Nov. 10, 2021, the disclosure of which is incorporated herein by reference in its entirety as part of the present application.

FIELD

The present disclosure relates to the field of medical instruments, in particular to a pad for acetabular bone revision and reconstruction and a fixing structure for a pad and an acetabular cup prosthesis.

BACKGROUND

The current methods for reconstructing acetabular bone defects include compression bone grafting, structural bone grafting, jumbo cup, reinforcing ring, cup-cage, 3D printing of a personalized acetabular cup prosthesis, etc. Using an allogeneic bone to treat a large-area bone defect cannot achieve good initial stability, so that prosthesis loosening and bone resorption are prone to occur. Kostensalo et al. reported 60 cases of hip joint revisions using a combination of the compression bone grafting and a cement cup. The patients were visited for averagely 7 years. An average survival rate was 73% if a second revision is taken as the end of the life. 13 of the 60 cases belong to aseptic loosening, which accounts for 81%.

It has been reported that whether it is an autologous or allogeneic large structural grafted bone, in a process of bone fusion, bone healing occurs only at a few millimeters from an outer layer of the grafted bone, while osteonecrosis remains in the center of the grafted bone. This leads to the collapse, resorption, and displacement of the grafted bone, which eventually leads to a failure of the revision.

The use of the Jumbo cup can reduce the use of a grafted bone. A center of rotation is moved outwards and downwards as far as possible to be close to an anatomical position, but a large Jumbo cup is not conducive to the recovery of bone mass, and makes it more difficult to second revision. Since good initial stability cannot be achieved, large anteroposterior columns and external upper bone defects limit the use of the large Jumbo cup.

The design of a metal porous structure is conducive to bone ingrowth, and its excellent friction coefficient is conducive to better original press-fitting, so as to provide good conditions for the initial stability and long-term stability of a prosthesis. The metal porous structure has been widely used in bone defect repair in the hip joint revision and achieves a good effect.

In the related art, a reconstruction method for repairing an acetabular bone defect using the design of a metal porous structure is generally used in combination with the pad. The pad is used to fill a defective part of an acetabular bone. The pad currently used on the market is of an integrated structure and a single type, is thicker, cannot reconstruct and fix bone defects with different shapes, and is poor in adaptability.

In view of the above-mentioned related technologies, the prior art discloses pads with an integrated structure, that cannot reconstruct and fix acetabular bones of different shapes, and have poor adaptability.

SUMMARY

The present invention provides a pad for acetabular bone revision and reconstruction and a fixing structure for a pad and an acetabular cup prosthesis.

In a first aspect, the present disclosure provides a pad for acetabular bone revision and reconstruction. The following technical solutions are adopted:

A pad for acetabular bone revision and reconstruction is provided. The pad is located between an acetabular cup prosthesis and the acetabular bone, and is connected to the acetabular cup prosthesis and the acetabular bone respectively; the pad includes a first component and a second component which has the same or different radius and shape as or from the radius and shape of the first component; the first component is movably connected with the second component; and the shape of the connected first component and second component is matched with a defective part of the acetabular bone.

The first component and the second component, which have the same or different radiuses and shapes, are movably connected, and the shape of their combination is matched with the shape of the defective part of the acetabular bone. Thus, more effectively repairing the defective part of the acetabular bone. The first component and the second component are applicable to acetabular bone defects with different shapes to better reconstruct and fix the acetabular bone, facilitate subsequent fixing of an acetabular cup prosthesis; and the split structure of the pad improves operation flexibility.

Optionally, the first component and the second component are of a ¼ or ⅛ spherical shape; thicknesses of the first component or the second component are uniformly and consistent, or the first component or the second component have thin edges and are gradually thickened towards a sphere center position, or have thick edges and are gradually thinned towards a sphere center position.

The shape and degree of wear of a defective part of the acetabular bone of each patient are different. Thus, it is necessary to prepare pads of different specifications to meet the needs of different patients. According to the designed pad, a first component and a second component which have the same thicknesses and the same radiuses can be combined and connected, and a first component and a second component which have different thicknesses and different radiuses can also be combined and connected. Combinations in different forms can be better applied to the acetabular bone defects of different patients, thus improving the comfort of the pad.

Optionally, a side wall of the first component or the second component is provided with a dovetail groove; a side wall of the second component or the first component is provided with a dovetail block used cooperatively with the dovetail groove; and the first component and the second component are movably connected through clamping between the dovetail groove and the dovetail block.

Additionally, the first component and the second component are connected through clamping between the dovetail groove and the dovetail block, so that the flexibility of operation of the pad is improved, and the working efficiency is also improved.

Optionally, the invention also comprises a length of a bottom surface of the dovetail groove that gradually decreases from the side close to the acetabular cup prosthesis to the side away from the acetabular bone; a longitudinal section of the dovetail groove is a frustum; a side surface of the dovetail block close to the bottom surface of the dovetail groove gradually decreases from the side close to the acetabular cup prosthesis to the side away from the acetabular bone; and a longitudinal section of the dovetail block is a frustum.

In another embodiment, the longitudinal sections of both of the dovetail groove and the dovetail block are the frustums, so that after they are clamped with each other, the dovetail block can be limited in an insertion direction to prevent the dovetail block from being separated from the dovetail groove in the insertion direction during insertion, thus defining that the dovetail groove and the dovetail block can only be separated from each other in one direction. Therefore, the degrees of freedom of the first component and the second component are restrained in a left direction, a right direction and a downward direction, and the firmness between the first component and the second component is guaranteed.

Optionally, a plurality of oblong mounting holes are formed in each of the first component and the second component; screws are inserted into the mounting holes, and a gap is reserved between the screws; and the first component and the second component are fixedly connected to the acetabular bone by inserting the screws into the mounting holes.

By adopting the above-mentioned technical solution, after the screws are inserted into the mounting holes, the screws can move up, down, left and right in the mounting holes. Since the screws need to be fixed at a thicker position on the acetabular bone, the screws can be fixed at proper positions on the acetabular bone by moving the positions of the screws in the mounting holes, so as to ensure the stability between the acetabular bone and the first component as well as the second component.

In a another aspect, the present disclosure provides a fixing structure for a pad and an acetabular cup prosthesis. The following technical solution is adopted.

In the fixing structure for the pad and the acetabular cup prosthesis, a plurality of circular slots are formed in each of the first component and the second component; a side surface of the acetabular cup prosthesis close to the pad is coated with bone cement; the first component and the second component are in contact with the acetabular cup prosthesis; and the first component and the second component are fixedly connected to the acetabular cup prosthesis by enabling the bone cement to enter the plurality of circular slots.

By adopting the above-mentioned technical solution, the bone cement coated on the acetabular cup prosthesis enters the plurality of circular slots, so that the engomphosis force between the bone cement and the pad is enhanced, thus improving the stability between the pad and the acetabular cup prosthesis.

Optionally, side surfaces of the first component and the second component close to the acetabular cup prosthesis are provided with cover layers, and notches of the circular slots are formed in the cover layers.

By adopting the above-mentioned technical solution, the engomphosis force between the bone cement and the pad is enhanced, so that the first component and the second component are fixedly connected to the acetabular cup prosthesis to effectively avoid the problem of pad loosening caused by collapse and resorption of a grafted bone and also avoid an extremely high shear force caused by fixing the acetabular cup prosthesis on the pad with the bone cement.

In conclusion, the present disclosure includes at least one of the following beneficial technical effects:

First, in the present disclosure, the first component and the second component which have the same or different radiuses and shapes are movably connected, and the shape of their combination is matched with the shape of the defective part of the acetabular bone, thus better repairing the defective part of the acetabular bone. The present disclosure is applicable to acetabular bone defects with different shapes to better reconstruct and fix the acetabular bone and facilitate subsequently fixing the acetabular cup prosthesis; and the split structure of the pad improves the operation flexibility.

Secondly, in the present disclosure, the bone cement coated on the acetabular cup prosthesis enters the plurality of circular slots, so that the engomphosis force between the bone cement and the pad is enhanced, thus improving the stability between the pad and the acetabular cup prosthesis.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The present disclosure is further described in detail below in combination with accompanying drawings1-7.

Embodiments of the present disclosure disclose a pad for acetabular bone revision and reconstruction and a fixing structure for a pad and an acetabular cup prosthesis.

Embodiment I

Referring toFIG.1, a pad for acetabular bone revision and reconstruction is located between an acetabular cup prosthesis and the acetabular, and is connected to the acetabular cup prosthesis and the acetabular bone respectively. The pad includes a first component1; a second component2is clamped on the first component1. The first component1and the second component2are of a ⅛ spherical shape. The radius and shape of the first component1are the same as those of the second component2. For the thickness, each of the first component1and the second component2has a thin edge and is gradually thickened towards a sphere center position. The edges of the first component1and the second component2extend into the acetabular bone. The shape of the clamped first component1and the second component2is of a ¼ spherical shape; and the shape and thickness of the clamped first component1and the second component2adapt to a defective part of the acetabular bone.

Referring toFIG.2andFIG.3, a side wall of the first component1close to the second component2is provided with a dovetail groove3, and a side wall of the second component2close to the first component1is provided with a dovetail block4. The dovetail block4and the dovetail groove3are clamped with each other to connect the first component1to the second component2.

A length of a bottom surface of the dovetail groove3gradually decreases from one side close to the acetabular cup prosthesis to one side away from the acetabular bone; a longitudinal section of the dovetail groove3is a frustum; a side surface of the dovetail block4close to the bottom surface of the dovetail groove3gradually decreases from the side close to the acetabular cup prosthesis to the side away from the acetabular bone; and a longitudinal section of the dovetail block (4) is a frustum. The frustum shape enables the dovetail block4and the dovetail groove3to be gradually tightened. After the dovetail block4is inserted into the dovetail groove3in a direction close to the acetabular cup prosthesis, the dovetail block4is prevented from being separated from the dovetail groove3.

A plurality of mounting holes5are formed in the first component1and the second component2. The mounting holes5are counterbores. The first component1and the second component2are fixedly connected to the acetabular bone in a manner of inserting screws into the mounting holes5. The mounting holes5are oblong. After the screws are inserted into the mounting holes5, due to the shape of the mounting holes5, gaps are served between the screws and hole walls of the mounting holes5, so that the screws can move in the mounting holes5, and the screws are adjusted to be fixed at thicker positions on the acetabular bone.

In the fixing structure for a pad and an acetabular cup prosthesis, side surfaces of the first component1and the second component2close to the acetabular cup prosthesis are provided with cover layers7. The first component1and the second component2are of bone trabecula structures, and the cover layers7are solid layers.

A plurality of circular slots6are formed in the cover layers7, the first component1and the second component2close to the acetabular cup prosthesis. Side surfaces of the acetabular cup prosthesis close to the first component1and the second component2are coated with one layer of bone cement. After the acetabular cup prosthesis is put into a recess formed by the first component1and the second component2, the bone cement on the acetabular cup prosthesis enters the plurality of circular slots6. The bone cement entering the circular slots6is formed into a bone cement column, so that the first component1and the second component2can be fixedly connected to the acetabular cup prosthesis. The depth of the circular slots6increases as the thickness of the first component1or the second component2gradually increases.

The first component1and the second component2cannot be fixed to the acetabular cup prosthesis directly through the bone cement. Since gaps of the bone trabecula are different in size, it is hard for the bone cement to penetrate into the gaps of the bone trabecula, or the engomphosis force between the bone cement that penetrates into the gaps of the bone trabecula and the gaps is poor, and the formed connection is weak, resulting in that the first component1and the second component2cannot be fixedly connected to the acetabular cup prosthesis. Therefore, by the arrangement of the cover layers7, the bone cement is prevented from penetrating into the gaps of the bone trabecula, but can directly enter the circular slots6.

The implementation principle of Embodiment I is as follows: The first component1and the second component2are clamped and put to the defective part of the acetabular bone; the screws are inserted into the mounting holes5and into the acetabular cup prosthesis to fixedly connect the first component1and the second component2to the acetabular cup prosthesis; the side surface of the acetabular cup prosthesis is then coated with one layer of bone cement; the acetabular cup prosthesis is put into the recess formed by the first component1and the second component2; the bone cement enters the circular slots and is then cured to complete connection of the pad to the acetabular cup prosthesis and the acetabular bone.

Embodiment II

Referring toFIG.4, the first component1and the second component2are of a ¼ spherical shape. The radius and shape of the first component1are the same as those of the second component2. For the thickness, each of the first component1and the second component2has a thin edge and is gradually thickened towards a sphere center position. The shape of the clamped first component1and the second component2is of a semi-spherical shape; and the shape and thickness of the clamped first component1and the second component2adapt to a defective part of the acetabular bone.

Referring toFIG.5andFIG.6, a side wall of the first component1close to the second component2is provided with a dovetail block4, and a side wall of the second component2close to the first component1is provided with a dovetail groove3. The dovetail block4and the dovetail groove3are clamped with each other to connect the first component1to the second component2.

Referring toFIG.7, side surfaces of the first component1and the second component2close to the acetabular bone are provided with a porous structural layer8that imitates a cancellous bone, which is conductive to the bone ingrowth of the acetabular bone in the acetabular cup prosthesis. The excellent friction coefficient of the porous structural layer is favorable for better original press-fitting, which provides good conditions for initial stability and long-term stability of the acetabular cup prosthesis. The porosity of 60%-80% of the porous structural layer8is conductive to the ingrowth of bone tissues; crosslinked micro structures are formed to achieve a long-term biological fixing effect; and the service life of the acetabular cup prosthesis is prolonged.

The implementation principle of Embodiment II is the same as that of Embodiment I, which will not be repeatedly described here.

In addition to the above two embodiments, the first component1and the second component2may adopt the following combination modes according to the defective condition of the acetabular bone:

(1) A first component1and a second component2which are uniform and consistent in thickness and have the same radiuses are selected to be combined;

or (2) a first component1and a second component2which are uniform and consistent in thickness and have different radiuses are selected to be combined;

or (3) a first component1which is uniform and consistent in thickness, and a second component2which has a thick edge, is gradually thinned towards a sphere center position and has the same radius as that of the first component1are selected to be combined;

or (4) a first component1which is uniform and consistent in thickness, and a second component2which has a thick edge, is gradually thinned towards a sphere center position and has a radius different from that of the first component1are selected to be combined;

or (5) a first component1and a second component2which both have thick edges, are gradually thinned towards a sphere center position and have the same radiuses are selected to be combined;

or (6) a first component1and a second component2which both have thick edges, are gradually thinned towards a sphere center position and have different radiuses are selected to be combined.

The preferred embodiments of the present disclosure are herein, and are not intended to limit the scope of the present disclosure or patent claims. Therefore, any equivalent changes made according to the structure, shape and principle of the present disclosure shall all fall within the protection scope of the present disclosure.