A distal anchoring cemented prosthesis stem

Abstract

The present application relates to a kind of distal anchoring bone cement type prosthesis stem, including stem body, several anchoring blades and piston.The bottom end of the stem body is fixed on prosthesis, top end is inserted into medullary cavity, bone cement channel is provided in the stem body along the axial direction, injection hole is formed on the side wall of the stem body, and the injection hole is communicated with the bone cement channel;The anchoring blade is arranged at the top of the stem body, the bottom of the anchoring blade is rotatably connected with the top end of the stem body, the piston is sleeved in the bone cement channel, and under the driving of bone cement, it slides upward, when the piston slides to the top of the stem body, several anchoring blades are opened, and the anchoring blade is converted from the first state to the second state.The distal anchoring bone cement type prosthesis stem can improve the long-term stability of tumor type prosthesis, reduce the aseptic loosening of prosthesis, and improve the long-term function of limb of patients with malignant bone tumor.

Description

Technical Field

[0001] This invention relates to a distally anchored bone cement prosthesis stem, belonging to the field of medical devices. Background Technology

[0002] In recent years, with the development of neoadjuvant chemotherapy, limb-sparing therapy has become a major treatment for primary malignant bone tumors, achieving good clinical results. A significant number of children have achieved long-term survival due to effective neoadjuvant chemotherapy and satisfactory surgical margins. Tumor-type prosthesis reconstruction is the most commonly used reconstruction method after resection of primary malignant bone tumors.

[0003] However, as the survival rate of patients undergoing tumor-related prosthesis reconstruction increases, prosthesis-related complications are becoming increasingly prominent, with aseptic loosening being a relatively common type of prosthesis-related complication. Studies have shown that the incidence of aseptic loosening of tumor-related prostheses is approximately 4.7%, accounting for 19% of all prosthesis failures, making it a relatively common cause of prosthesis failure.

[0004] Unlike conventional prostheses, tumor prostheses often require effective fixation of the prosthesis stem within the medullary cavity to maintain the stability of a large segment of the prosthesis. When the patient bears weight, the prosthesis stem often bears significant axial and rotational stress. Therefore, whether biological fixation or cement fixation is used within the medullary cavity, the prosthesis stem is more prone to loosening under long-term high stress, which in turn affects the patient's weight-bearing and normal walking function.

[0005] Managing loosening of tumor-type prostheses is a particularly challenging issue. Because of significant bone loss around the prosthesis stem after loosening, revision surgery for limb defect reconstruction becomes extremely difficult. Patients often require revision surgery with a complete tumor-type prosthesis (such as a total femur or humerus) to restore limb continuity. This not only increases the financial burden on patients but also significantly impacts post-revision limb function. Furthermore, advancements in neoadjuvant chemotherapy for common bone malignancies like osteosarcoma and Ewing sarcoma have led to significantly extended survival times and even cures for many children and adolescents. This poses a substantial challenge to the long-term stability of reconstructed tumor-type prostheses. In addition to weight-bearing stress, the thickening of the bone and medullary cavity in children and adolescents also significantly threatens the long-term stability of the tumor-type prosthesis stem. Summary of the Invention

[0006] To address the aforementioned problems, the purpose of this invention is to provide a distally anchored cemented prosthesis stem that can improve the long-term stability of tumor-type prostheses, reduce aseptic loosening of the prosthesis, and improve the long-term limb function of patients with malignant bone tumors.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] This invention provides a distally anchored bone cement prosthesis stem, comprising:

[0009] The stem has its bottom end fixed to the prosthesis and its top end inserted into the medullary cavity. The stem contains a bone cement channel, and an injection hole is formed on the side wall of the stem, which communicates with the bone cement channel.

[0010] A plurality of anchoring blades are disposed at the top of the handle, the bottom of the anchoring blades being rotatably connected to the top of the handle, the anchoring blades having a first state and a second state. When the anchoring blades are in the first state, the top of the anchoring blades is tilted inward, and a conical surface is formed between the plurality of anchoring blades. When the anchoring blades are in the second state, the plurality of anchoring blades are opened outward.

[0011] A piston is fitted inside the bone cement channel and slides upward under the pushing action of the bone cement. When the piston slides to the top of the handle, it opens up a plurality of anchoring blades, causing the anchoring blades to change from the first state to the second state.

[0012] The anchoring blades include multiple blades, which are evenly arranged along the circumferential direction.

[0013] The anchoring blade has several fine holes.

[0014] The piston has a through hole through which bone cement enters the medullary cavity.

[0015] The anchoring blade is made of metal.

[0016] The piston is made of metal.

[0017] The piston is also provided with a sealing ring on its outer wall, and the piston is slidably connected to the bone cement channel through the sealing ring.

[0018] A threaded hole is formed in the injection hole. The bone cement pressure injector is threadedly connected to the injection hole through a connector. The bone cement pressure injector injects cement into the injection hole and bone cement channel through the connector.

[0019] The present invention has the following advantages due to the adoption of the above technical solutions:

[0020] The anchoring blade at the top, pushed by the piston, changes from retracting to opening. Under the combined action of cortical pressure within the medullary cavity and bone cement, the anchoring blade integrates with the interface of the medullary cavity, thereby reducing the incidence of long-term loosening.

[0021] The anchoring blade has a porous metal structure. Under the pressure of bone cement within the prosthesis stem, the anchoring blade can open distally and circumferentially, achieving initial pressure on the medullary canal wall. This facilitates bone ingrowth into the medullary canal wall and promotes integration between the prosthesis stem and the medullary canal interface. Attached Figure Description

[0022] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts. In the drawings:

[0023] Figure 1 This is a schematic diagram of the distally anchored bone cement prosthesis stem in its first state.

[0024] Figure 2 This is a schematic diagram of the distally anchored bone cement prosthesis stem in its second state.

[0025] Figure 3 This is a schematic diagram of the piston structure;

[0026] Figure 4 This is a schematic diagram showing the state of the distally anchored bone cement prosthesis stem;

[0027] The markings in the attached diagram are as follows:

[0028] 1-Handle, 2-Anchoring blade, 3-Prosthesis, 4-Bone cement pressure injector, 5-Connector, 6-Piston, 11-Injection hole, 12-Bone cement channel, 61-Through hole, 62-Boss. Detailed Implementation

[0029] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the invention and to fully convey the scope of the invention to those skilled in the art.

[0030] An embodiment of the present invention provides a distally anchored cemented prosthesis stem, comprising a stem body, a plurality of anchoring blades, and a piston. The bottom end of the stem body is fixed to the prosthesis, and the top end is inserted into the medullary cavity. A cemented channel is provided along the axial direction within the stem body, and an injection hole is formed on the side wall of the stem body, the injection hole communicating with the cemented channel. The anchoring blades are disposed at the top of the stem body, and the bottom of the anchoring blades is rotatably connected to the top end of the stem body. The anchoring blades have a first state and a second state. When the anchoring blades are in the first state, the top end of the anchoring blades is inclined inward, and a conical surface is formed between the plurality of anchoring blades. When the anchoring blades are in the second state, the plurality of anchoring blades are opened outward. The piston is sleeved within the cemented channel and slides upward under the pushing action of the cement. When the piston slides to the top of the stem body, it expands the plurality of anchoring blades, causing the anchoring blades to change from the first state to the second state. The distally anchored cemented prosthesis stem can improve the long-term stability of tumor-type prostheses, reduce aseptic loosening of the prosthesis, and improve the long-term limb function of patients with malignant bone tumors.

[0031] Example 1

[0032] like Figures 1 to 4 As shown, an embodiment of the present invention provides a distal anchored bone cement prosthesis stem, including a stem body 1, a plurality of anchoring blades 2 and a piston 6. The bottom end of the handle 1 is fixed to the prosthesis 3, and the top end is inserted into the medullary cavity. A bone cement channel 12 is provided in the handle 1 along the axial direction. An injection hole 11 is formed on the side wall of the handle 1, and the injection hole 11 communicates with the bone cement channel 12 and is perpendicular to the bone cement channel 12. Anchoring blades 2 are disposed at the top of the handle 1, and the bottom of the anchoring blades 2 is rotatably connected to the top end of the handle 1. The anchoring blades 2 have a first state and a second state. When the anchoring blades 2 are in the first state, the top end of the anchoring blades 2 is tilted inward, and a conical surface is formed between several anchoring blades 2. When the anchoring blades 2 are in the second state, several anchoring blades 2 are opened outward. The piston 6 is sleeved in the bone cement channel 12 and slides upward under the pushing action of the bone cement. When the piston 6 slides to the top of the handle 1, it opens several anchoring blades 2, so that the anchoring blades 2 change from the first state to the second state.

[0033] When using the prosthesis stem, the bottom of the prosthesis stem is first fixedly installed on the prosthesis 3, and the top is inserted into the medullary cavity. Then, bone cement is injected into the bone cement channel 12 through the injection hole 11. After the bone cement is injected into the bone cement channel 12, the bone cement pushes the piston 6 to spread evenly to the distal end of the prosthesis stem until the piston 6 is pushed to the top of the stem. The piston 6 opens the anchoring blade 2 to pressurize the bone of the medullary cavity wall or to fit tightly with the bone cement at the distal end of the medullary needle, so as to achieve enhanced fixation of the distal end of the prosthesis stem.

[0034] The bone cement channel 12 is a cylindrical channel, and the piston 6 is a cylindrical piston. The piston 6 is fitted inside the bone cement channel 12 and slides upward along the bone cement channel 12 under the pushing action of the bone cement. A constriction is formed at the top of the bone cement channel 12, and a boss 62 is formed on the side wall of the piston 6. When the piston 6 slides to the top of the bone cement channel 12, the top of the piston 6 extends out from the constriction and opens the anchoring blade 2. The boss 62 is limited by the action of the constriction.

[0035] The piston 6 has a through hole 61 through which bone cement enters the medullary cavity. The bone cement pushes the piston 6 upwards and, together with the medulla, enters the medullary cavity through the through hole 61 to anchor and fix the anchoring blade 2 within the medullary cavity. This, combined with the medulla, further improves the long-term stability of the prosthesis.

[0036] The anchoring blades 2 include multiple blades, which are evenly arranged along the circumference. Preferably, there are three blades. The anchoring blades 2 can also be one, two, or more than three.

[0037] The anchoring blade 2 and the top of the handle 1 can be connected by a rotating shaft, so that it can open outward under the squeezing and pushing action of the piston.

[0038] The anchoring blade 2 has several fine holes. The anchoring blade 2 has a metal porous structure. Under the pressure of bone cement in the prosthesis stem, the anchoring blade 2 can be opened distally and circumferentially to achieve initial pressure on the medullary canal wall, which is conducive to bone ingrowth into the medullary canal wall and promotes the integration of the prosthesis stem with the medullary canal interface.

[0039] To improve the stability of long-term fixation of the prosthesis, the anchoring blade 2 is preferably made of a metal material.

[0040] To improve the stability of long-term fixation of the prosthesis, the piston 6 is preferably made of a metal material.

[0041] To increase the driving force on the piston, a sealing ring is provided on the outer wall of the piston 6, and the piston is slidably connected to the bone cement channel 12 through the sealing ring.

[0042] A threaded hole is formed in the injection hole 11. The bone cement pressure injector 4 is threadedly connected to the injection hole 11 via a connector 5, and injects cement into the injection hole 11 and the bone cement channel 12. The connector 5 can be a connecting tube, one end of which is fixedly connected to the threaded connection in the injection hole 11, and the other end is connected to the bone cement pressure injector 4.

[0043] The working principle of the above-mentioned distally anchored cemented prosthesis stem is as follows:

[0044] The bone cement pressure injector 4 is threadedly connected to the injection hole via connector 5;

[0045] The bone cement pressure injector 4 injects bone cement evenly into the injection hole 11. The bone cement enters the bone cement channel 12, pushing the piston 6 upward until it reaches the top of the straight handle 1.

[0046] When the piston 6 extends from the top of the handle 1 and squeezes and expands the anchoring blade 2;

[0047] The anchoring blades 2 are used to reinforce the distal end of the prosthesis stem by applying pressure to the bone wall of the medullary cavity or by tightly adhering to the bone cement at the distal end of the medullary needle.

[0048] Distal anchoring of cemented prosthesis stems can improve the long-term stability of tumor-type prostheses, reduce aseptic loosening of the prosthesis, and improve the long-term limb function of patients with malignant bone tumors.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A distally anchored bone cement prosthesis stem, characterized in that, include: The stem has its bottom end fixed to the prosthesis and its top end inserted into the medullary cavity. The stem contains a bone cement channel, and an injection hole is formed on the side wall of the stem, which communicates with the bone cement channel. A plurality of anchoring blades are disposed at the top of the handle, the bottom of the anchoring blades being rotatably connected to the top of the handle, the anchoring blades having a first state and a second state. When the anchoring blades are in the first state, the top of the anchoring blades is tilted inward, and a conical surface is formed between the plurality of anchoring blades. When the anchoring blades are in the second state, the plurality of anchoring blades are opened outward. A piston is fitted inside the bone cement channel and slides upward under the pushing action of the bone cement. When the piston slides to the top of the handle, it opens up a plurality of anchoring blades, causing the anchoring blades to change from the first state to the second state.

2. The distally anchored cemented prosthesis stem according to claim 1, characterized in that, The anchoring blades include multiple blades, which are evenly arranged along the circumferential direction.

3. The distally anchored cemented prosthesis stem according to claim 1, characterized in that, The anchoring blade has several fine holes.

4. The distally anchored cemented prosthesis stem according to claim 1, characterized in that, The piston has a through hole through which bone cement enters the medullary cavity.

5. The distally anchored cemented prosthesis stem according to claim 1, characterized in that, The anchoring blade is made of metal.

6. The distally anchored cemented prosthesis stem according to claim 1, characterized in that, The piston is made of metal.

7. The distally anchored cemented prosthesis stem according to claim 1, characterized in that, The piston is also provided with a sealing ring on its outer wall, and the piston is slidably connected to the bone cement channel through the sealing ring.

8. The distally anchored cemented prosthesis stem according to claim 1, characterized in that, A threaded hole is formed in the injection hole. The bone cement pressure injector is threadedly connected to the injection hole through a connector. The bone cement pressure injector injects cement into the injection hole and bone cement channel through the connector.

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