Intramedullary bone cement support rod for proximal humerus fractures

Abstract

The present application relates to the field of orthopedic biomedical technology, specifically, a proximal humerus fracture intramedullary bone cement support rod, which comprises a bone plate, a plurality of first connecting holes and a plurality of second connecting holes are formed on one side of the bone plate, and a solid bone nail is arranged in the first connecting hole. The device can inject bone cement into the bone marrow cavity through the injection channel and the injection port, and then solidify into a rod body to tightly fill the bone marrow cavity space. Through the cooperation of the bone plate and the bone cement support rod in the bone marrow cavity space, a support structure is formed on both sides of the humerus, the stress during the movement of the patient's arm is evenly distributed on both sides of the humerus, the fixation stability is significantly improved, the risk of internal fixation failure such as steel plate displacement and screw cutting is effectively reduced, the bone cement support rod can also prevent the displacement of the fracture block, promote the repair of the fracture, reduce the extrusion and friction of the surrounding tissue of the filling part, reduce the inflammatory reaction and postoperative pain, and improve the comfort of the patient's recovery.

Description

Technical Field

[0001] This invention relates to the field of orthopedic biomedical technology, specifically to an intramedullary bone cement support rod for proximal humeral fractures. Background Technology

[0002] Proximal humeral fractures are a common type of osteoporotic fracture in the elderly. Due to widespread osteoporosis in elderly patients, the bone strength of the proximal humerus is significantly reduced. After a fracture, the humeral head often presents as an "eggshell" shape with severe comminution of the medial column, leading to collapse of the medial supporting structure and loss of the neck-shaft angle. This complex fracture morphology presents significant challenges to traditional open reduction and internal fixation techniques with plates and screws: on the one hand, compression defects in the cancellous bone make reduction difficult and difficult to maintain; on the other hand, the porous bone cannot provide sufficient holding force for the internal fixation devices (such as plates and screws), resulting in a very high risk of screw cutting, plate displacement, and internal fixation failure (such as screw or plate dislodgement) postoperatively.

[0003] To address the lack of medial support, existing techniques often employ bone grafting for filling and support, primarily divided into two methods: one is autologous bone grafting, which requires bone to be harvested from other parts of the patient's body (such as the iliac bone). This not only increases surgical trauma and time, but more importantly, the quantity and quality of autologous bone in elderly patients with osteoporosis are often poor, making it difficult to provide effective structural support, and there is a risk of complications at the bone harvesting site; the other is allogeneic bone grafting, which usually uses allogeneic fibula or femoral segments for support. However, these allogeneic bone materials are scarce, difficult to procure, and extremely expensive. Furthermore, allogeneic bone grafting also carries potential risks of immune rejection, disease transmission, and high postoperative infection rates.

[0004] Therefore, how to effectively and safely reconstruct comminuted fractures, especially the stable support of the medial column, while overcoming the fixation difficulties caused by osteoporosis and reducing the risk of internal fixation failure, remains a pressing challenge in clinical practice. Summary of the Invention

[0005] This invention provides an intramedullary bone cement support rod for proximal humeral fractures. Bone cement is injected into the medullary cavity of the humerus through an injection channel and injection port within a hollow bone screw. After the bone cement fills the medullary cavity and solidifies, it forms a bone cement support rod that, in conjunction with a bone plate, provides support on the inner and outer sides of the humerus, thereby solving the problems mentioned in the background art.

[0006] In elderly patients with osteoporotic proximal humeral fractures, the porous bone is insufficient to provide effective support for traditional plate and screw internal fixation. Bone grafting techniques present challenges such as the inability of autologous bone harvesting to provide effective support, and the high cost and potential immune rejection associated with allogeneic bone grafting.

[0007] To achieve the above objectives, the intramedullary bone cement support rod for proximal humeral fractures includes a bone plate. One side of the bone plate has several No. 1 connecting holes and several No. 2 connecting holes. A solid bone nail is disposed inside each of the No. 1 connecting holes, and a hollow bone nail is disposed inside each of the No. 2 connecting holes. Each hollow bone nail includes an injection channel and several injection ports, which are connected to the injection channel. After the hollow bone nail enters the humerus, bone cement is injected into the medullary cavity of the humerus through the injection channel and injection ports. The bone cement fills the medullary cavity, and after solidification, it forms a bone cement support rod inside the humerus, simultaneously providing support on both the inner and outer sides of the humerus in conjunction with the bone plate.

[0008] In the above technical solution, bone cement is injected into the medullary cavity through the injection channel and injection port of the hollow bone screw and solidifies into a rod, tightly filling the medullary cavity space. Through the cooperation of the bone plate and the bone cement support rod in the medullary cavity space, a support structure is formed simultaneously on the inner and outer sides of the humerus. This allows the stress during the patient's arm movement to be evenly distributed on both sides of the humerus, significantly improving fixation stability and effectively reducing the risk of internal fixation failure such as plate displacement and screw cutting. The bone cement support rod can also prevent fracture fragment displacement, promote fracture repair, reduce the compression and friction of surrounding tissues at the filling site, reduce inflammatory response and postoperative pain, and improve the patient's rehabilitation comfort.

[0009] In another technical solution, a sliding sleeve is provided on the outside of the hollow bone screw. The sliding sleeve is used to cover the injection port during the insertion of the hollow bone screw into the humerus to prevent bone fragments from entering the injection channel through the injection port. A plurality of injection ports are opened on the outside of the screw shank, and the plurality of injection ports are evenly distributed along the axial direction of the screw shank. The hollow bone screw includes a tail, a shank, and a head. The tail is fixedly connected to the shank, and the shank is threadedly connected to the head. The injection channel is opened inside the tail and shank. Two symmetrically distributed grooves are provided on the outside of the sliding sleeve, and two [unclear] are fixedly connected inside the second connecting hole. Symmetrically distributed guide keys are slidably connected to grooves; a filler strip, made of deformable elastic material, is fixedly connected inside the groove, and the guide key abuts against the filler strip when the guide key is inside the groove; a guide baffle is fixedly connected to the outside of the injection port, which is used to prevent bone fragments from entering the injection port when the nail rod rotates; the opening direction of the guide baffle is opposite to the rotation direction when the hollow bone nail is screwed into the humerus, and is used to deflect bone fragments when the hollow bone nail is screwed into the humerus; a receiving cavity is opened at one end of the sliding sleeve near the injection port, and when the sliding sleeve covers the injection port, several of the guide baffles are located inside the receiving cavity.

[0010] In this technical solution, during the insertion of the hollow bone screw into the humerus, the sliding sleeve completely covers the injection port. At the same time, a guide baffle is set outside the injection port with an opening direction opposite to the rotation direction when the hollow bone screw is inserted into the humerus. When the hollow bone screw is inserted into the humerus, it bounces away bone fragments, which can effectively prevent bone fragments from blocking the injection port or entering the injection channel. This avoids the risk of abnormal injection pressure and bone cement leakage caused by bone fragments. In addition, the filling strip fills the groove, which can keep the outer wall of the sliding sleeve smooth and prevent the groove from scraping the bone during implantation, causing additional damage.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0012] 1. In this intramedullary bone cement support rod for proximal humeral fractures, bone cement is injected into the medullary cavity through the injection channel and injection port and then solidifies into a rod that tightly fills the medullary cavity space. Through the cooperation between the bone plate and the bone cement support rod in the medullary cavity space, a support structure is simultaneously formed on both the inner and outer sides of the humerus. This allows the stress during the patient's arm movement to be evenly distributed on both sides of the humerus, significantly improving fixation stability and effectively reducing the risk of internal fixation failure such as plate displacement and screw cutting. The bone cement support rod can also prevent fracture fragment displacement, promote fracture repair, reduce compression and friction of surrounding tissues at the filling site, reduce inflammatory response and postoperative pain, and improve the patient's rehabilitation comfort.

[0013] 2. In this intramedullary bone cement support rod for proximal humeral fractures, the sliding sleeve completely covers the injection port during the insertion of the hollow bone screw into the humerus. This effectively prevents bone fragments from clogging the injection port or entering the injection channel, thus avoiding the risk of abnormal injection pressure and bone cement leakage caused by bone fragments. At the same time, a guide baffle is set outside the injection port with an opening direction opposite to the rotation direction of the hollow bone screw when it is inserted into the humerus. This baffle can bounce away bone fragments when the sliding sleeve moves to expose the injection port and the hollow bone screw is still rotating. This prevents bone fragments from entering the injection channel due to medical staff not stopping the rotation of the hollow bone screw in time, thus improving the safety of the surgical procedure. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the overall structure of the present invention;

[0015] Figure 2 This is a schematic diagram showing the disassembled structure of the bone plate, solid bone screw, and hollow bone screw in this invention;

[0016] Figure 3 This is a schematic diagram of the overall structure of the hollow bone nail in this invention;

[0017] Figure 4 This is a schematic diagram of the disassembly structure of the hollow bone nail after cross-section of the sliding sleeve in this invention;

[0018] Figure 5 For the present invention Figure 4 Enlarged schematic diagram of the structure at point A;

[0019] Figure 6 This is a schematic diagram illustrating the state changes of the injection port before and after exposure in this invention;

[0020] Figure 7 This is a schematic diagram showing the state changes of a portion of the structure before and after the hollow bone nail enters the No. 2 connecting hole in this invention.

[0021] Figure 8 This is a schematic diagram of the overall structure of the bone cement support rod after molding in this invention;

[0022] Figure 9 This is a schematic diagram showing the fit between the bone cement support rod and the humerus when implanted using the method described in Example 2.

[0023] The meanings of the labels in the diagram are as follows:

[0024] 1. Bone plate; 11. Connecting hole No. 1; 12. Connecting hole No. 2; 121. Guide key;

[0025] 2. Solid bone screws;

[0026] 3. Hollow bone screw; 31. Screw end; 32. Screw rod; 33. Screw head; 34. Injection channel; 341. Injection port; 35. Sliding sleeve; 351. Receiving cavity; 36. Guide baffle; 37. Filler strip. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Example 1: Currently, for osteoporotic proximal humeral fractures in the elderly, the porous bone is insufficient to provide effective support for traditional plate and screw internal fixation. Bone grafting techniques face challenges such as the difficulty of providing effective support from autologous bone harvesting, and the high cost and potential immune rejection of allogeneic bone. This invention provides an intramedullary bone cement support rod for proximal humeral fractures. (See [link]) Figure 1 - Figure 5As shown, the bone plate 1 has several No. 1 connecting holes 11 and several No. 2 connecting holes 12 through one side. Solid bone nails 2 are installed inside the No. 1 connecting holes 11, and hollow bone nails 3 are installed inside the No. 2 connecting holes 12. The hollow bone nail 3 includes a nail tail 31, a nail shank 32, and a nail head 33. The nail tail 31 is fixedly connected to the nail shank 32, and the nail head 33 is threadedly connected to the nail shank 32. Injection channels 34 are opened inside the nail tail 31 and the nail shank 32. Several injection ports 341 communicating with the injection channels 34 are evenly opened on the outside of the nail shank 32. A sliding sleeve 35 is provided on the outside of the nail shank 32. Guide baffles 36 are fixedly connected to one side of each of the injection ports 341.

[0029] Among them, see Figure 1 and Figure 2 As shown, the bone plate 1 is wider at the top and narrower at the bottom. When a fracture occurs at the proximal end of the humeral head, the wider side at the top is used to connect the humeral head, and the narrower side at the bottom is used to connect the humeral body. The solid bone nail 2 and the hollow bone nail 3 pass through the first connecting hole 11 and the second connecting hole 12 respectively and are drilled into the humerus to connect the bone plate 1 and the fractured humerus on both sides. The bone plate 1 fixes the position of the humerus and promotes the healing of the fractured humerus.

[0030] It should be noted that hollow bone nails 3 are installed on both the upper and lower sides of the bone plate 1, and their specific number depends on the surgical requirements. After the hollow bone nails 3 are drilled into the humerus, bone cement is injected into the medullary cavity of the humerus through the injection channel 34. The bone cement is finally injected into the medullary cavity through the injection port 341, and ultimately forms a structure like... Figure 8 The support rod shown forms an inner support within the medullary cavity of the humerus. Working in conjunction with the bone plate 1, it evenly distributes stress on both sides of the humerus during arm movement, creating a more stable and durable support structure. The bone cement support rod can also be used to fill the medullary cavity to prevent fracture fragment displacement, promoting fracture repair. Furthermore, the filling effect of the bone cement support rod effectively reduces compression and friction of surrounding tissues at the medullary cavity filling site, resulting in better fit, effectively reducing inflammation, and alleviating patient pain.

[0031] Furthermore, since the bones of elderly patients are more fragile, large bone fragments will be generated when the hollow bone nail 3 is drilled into the humerus. These bone fragments may block the injection port 341 when the hollow bone nail 3 is drilled in, or even enter the injection channel 34 from the injection port 341. This will cause a sudden increase in pressure when bone cement is injected into the medullary cavity, and the bone cement may seep from the fracture site into the fracture line, thereby hindering the healing of the humeral fracture site. Therefore, the sliding sleeve 35 is used to cover the injection port 341 when the hollow bone nail 3 enters the humerus to prevent bone fragments from entering the injection port 341 during this process.

[0032] The following is a specific disclosure of a structure by which the sliding sleeve 35 achieves the above effect:

[0033] See Figure 4 , Figure 5 and Figure 7 As shown, the sliding sleeve 35 is threadedly connected to the nail rod 32. Two symmetrical grooves are opened on the outside of the sliding sleeve 35. A filler strip 37 is fixedly connected inside the groove. The filler strip 37 is made of medical grade silicone. Two symmetrically distributed guide keys 121 are fixedly connected to the inner wall of the second connection hole 12. The guide keys 121 are slidably connected to the groove, and the guide keys 121 abut against the filler strip 37.

[0034] See Figure 6 As shown, the specific process is as follows: First, the medical staff first installs the sliding sleeve 35 to the outside of the nail rod 32 through the thread. After ensuring that the sliding sleeve 35 covers the injection port 341, the nail head 33 is connected to the nail rod 32. Next, the medical staff makes a hole in the humerus for the hollow bone nail 3 to enter. Then, the medical staff aligns the two grooves of the hollow bone nail 3 with the two guide keys 121 and inserts the hollow bone nail 3 along the direction of the grooves. After insertion, the medical staff uses a tool to turn the nail tail 31, so that the nail rod 32 and the nail head 33 rotate together. During this process, due to the limiting effect between the guide key 121 and the groove, the sliding sleeve 35 does not rotate with the hollow bone nail 3, but slides on the nail rod 32, thereby gradually exposing the injection port 341.

[0035] See Figure 7 As shown, after the guide key 121 enters the groove, it will compress the filling strip 37, causing it to deform. During the movement of the sliding sleeve 35, the part of the filling strip 37 that is abutted by the guide key 121 changes continuously. The part that is separated from the abutment will return to its original state. The reason for setting the filling strip 37 inside the groove is that if the groove is not covered, when the sliding sleeve 35 enters the humerus, once the groove on the outer wall of the sliding sleeve 35 comes into contact with the humerus, it will further cause wear on the humerus during the entry process. By filling the groove with the filling strip 37, the outer surface of the sliding sleeve 35 can still remain cylindrical, so as to avoid the groove from wearing on the humerus.

[0036] Furthermore, the sliding sleeve 35 has a receiving cavity 351 at one end near the injection port 341. When the sliding sleeve 35 covers the injection port 341, several guide baffles 36 are arranged inside the receiving cavity 351. The opening of the guide baffles 36 faces the opposite direction to the rotation direction when the hollow bone nail 3 enters the humerus.

[0037] After the sliding sleeve 35 moves and exposes the injection port 341, the hollow bone screw 3 may not stop rotating in time due to the operation of medical staff. During the period from when the injection port 341 is exposed to when the medical staff stops operating, some bone fragments may still enter the injection port 341. At this time, since the opening of the guide baffle 36 is opposite to the rotation direction when the hollow bone screw 3 enters the humerus, the guide baffle 36 will bounce the bone fragments away during the rotation of the hollow bone screw 3, thereby further preventing bone fragments from entering the injection port 341 and improving the safety of the device.

[0038] The working principle of this device is as follows:

[0039] First, the medical staff used a special drill bit to make holes corresponding to the solid bone nail 2 and the hollow bone nail 3 at the fracture site of the patient's humerus according to the specific needs of the surgery. Then, the medical staff placed the bone plate 1 at the two bones above and below the fracture site of the humerus. The wider end of the bone plate 1 corresponds to the head of the humerus, and the narrower end corresponds to the body of the humerus. Then, the medical staff screwed the solid bone nail 2 and the hollow bone nail 3 into the corresponding holes respectively.

[0040] During this process, medical staff first screw the solid bone nail 2 into the hole through the first connecting hole 11, and then place the hollow bone nail 3 into the second connecting hole 12, ensuring that the two grooves of the sliding sleeve 35 correspond to the two guide keys 121 in the second connecting hole 12. Then, the medical staff insert the two guide keys 121 into the grooves and gradually slide the hollow bone nail 3 into the corresponding hole on the humerus. When the hollow bone nail 3 can no longer be slid into the humerus, the medical staff use a tool to connect with the nail tail 31 and use the tool to rotate the hollow bone nail 3 to continue entering the hole. During this period, due to the limiting effect of the guide key 121 on the groove, the sliding sleeve 35 cannot rotate with the nail rod 32. As the nail rod 32 continues to go deeper, the sliding sleeve 35 slides on the nail rod 32, thereby gradually exposing the injection port 341.

[0041] After the hollow bone nail 3 is fully inserted into the hole, the medical staff can stop rotating the hollow bone nail 3. Then, the injection molding equipment is connected to the injection channel 34 of the nail tail 31 and the bone cement is injected. The bone cement is finally injected into the medullary cavity of the humerus through the injection port 341. Through continuous injection of bone cement, the bone cement will gradually fill the medullary cavity of the humerus to form a support rod. During the injection process, the medical staff should monitor the amount of bone cement injected throughout the process using X-ray observation technology to avoid injecting too much or too little bone cement.

[0042] If bone fragments may still enter the injection port 341 during the period between when the injection port 341 is exposed and when the medical staff stops operating, then because the opening of the guide baffle 36 is opposite to the rotation direction when the hollow bone nail 3 enters the humerus, the guide baffle 36 will bounce the bone fragments away during the rotation of the hollow bone nail 3, thereby further preventing bone fragments from entering the injection port 341.

[0043] After the bone cement injection is completed, medical staff can disconnect the injection equipment from the injection channel 34 and suture the patient's wound. After the bone cement support rod solidifies, it forms an inner support in the medullary cavity of the humerus. It works in conjunction with the bone plate 1 to evenly distribute the stress during the patient's arm movement on both sides of the humerus, forming a more stable and durable support structure. At the same time, the bone cement support rod can also be used to fill the medullary cavity to prevent the displacement of the fracture fragments, which is conducive to promoting fracture repair. Furthermore, the filling of the bone cement support rod can effectively reduce the compression and friction of the surrounding tissues at the filling site of the medullary cavity, resulting in better fit.

[0044] Example 2 This example provides another method for shaping and implanting a bone cement support rod, which includes the following steps:

[0045] Step 1: First, medical staff will perform an X-ray or CT scan on a point 1-2 cm below the surgical neck of the patient's humerus. Afterward, the medical staff will analyze the shape of the area based on the scan results.

[0046] Step 2: After analyzing the shape of the location, medical staff mold the bone cement raw material into shape so that the formed bone cement support rod fits the shape of the location.

[0047] Step 3: After the bone cement has hardened, the medical staff will perform surgery on the patient at that location and attach the bone cement support rod to the location. Finally, the medical staff will use solid bone screws 2 to fix the bone cement support rod to the patient's humerus.

[0048] For details, see Figure 9 As shown, when installing the bone cement support rod according to the above steps, the bone cement support rod fits into the concave surface of the surgical neck. For older patients, this area is more fragile than for younger patients. Therefore, when installing the bone cement support rod in this position, it can further fit the humerus and provide more stable support for the concave surface. When shaping the end of the bone cement support rod, it should have the same or similar curvature as the surgical neck of the patient's humerus.

[0049] More importantly, medical tool manufacturing plants can mass-produce bone cement support rods of different sizes based on the approximate shape of the surgical neck of the humerus in ordinary people. In this way, during the operation, medical staff can directly apply the pre-prepared and size-matched bone cement support rods to the operation based on the results of X-ray or CT scans, reducing the steps of manual shaping during the operation and improving the efficiency of the operation.

[0050] It should be noted that the average length of the surgical cervical indentation in ordinary people is roughly between 8 and 15 mm, while the medullary cavity of the elderly may be enlarged due to osteoporosis. Therefore, when factories mass-produce bone cement support rods of different sizes, the size can be increased by 10% to 20% accordingly.

[0051] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely preferred examples and are not intended to limit the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. An intramedullary bone cement support rod for proximal humeral fractures, comprising a bone plate (1), characterized in that: The bone plate (1) has several No. 1 connecting holes (11) and several No. 2 connecting holes (12) through one side. A solid bone nail (2) is installed inside the No. 1 connecting hole (11), and a hollow bone nail (3) is installed inside the No. 2 connecting hole (12). The hollow bone nail (3) includes an injection channel (34) and several injection ports (341). The injection ports (341) are connected to the injection channel (34). After the hollow bone nail (3) enters the humerus, bone cement is injected into the medullary cavity of the humerus through the injection channel (34) and the injection ports (341). The bone cement will fill the medullary cavity. After the bone cement solidifies, it will form a bone cement support rod inside the humerus, which will work with the bone plate (1) to form support on both the inner and outer sides of the humerus. The hollow bone screw (3) is provided with a sliding sleeve (35) on the outside. The sliding sleeve (35) is used to cover the injection port (341) during the process of the hollow bone screw (3) entering the humerus, so as to prevent bone fragments from entering the injection channel (34) through the injection port (341). The sliding sleeve (35) has two symmetrically distributed grooves on its outside, and the second connecting hole (12) has two symmetrically distributed guide keys (121) fixedly connected inside, and the guide keys (121) are slidably connected to the grooves. A filling strip (37) is fixedly connected inside the groove. The filling strip (37) is made of deformable elastic material. When the guide key (121) is located inside the groove, the guide key (121) abuts against the filling strip (37). A guide baffle (36) is fixedly connected to the outside of the injection port (341). The guide baffle (36) is used to prevent bone fragments from entering the injection port (341) when the rod part (32) of the hollow bone nail (3) rotates.

2. The intramedullary bone cement support rod for proximal humeral fractures according to claim 1, characterized in that: The hollow bone screw (3) includes a tail (31), a shank (32) and a head (33). The tail (31) is fixedly connected to the shank (32), and the shank (32) is threadedly connected to the head (33). The injection channel (34) is opened inside the tail (31) and the shank (32).

3. The intramedullary bone cement support rod for proximal humeral fractures according to claim 2, characterized in that: A plurality of injection ports (341) are provided on the outside of the nail rod portion (32), and the plurality of injection ports (341) are evenly distributed along the axial direction of the nail rod portion (32).

4. The intramedullary bone cement support rod for proximal humeral fractures according to claim 1, characterized in that: The opening direction of the guide baffle (36) is opposite to the rotation direction when the hollow bone nail (3) is screwed into the humerus, and is used to bounce off bone fragments when the hollow bone nail (3) is screwed into the humerus.

5. The intramedullary bone cement support rod for proximal humeral fractures according to claim 4, characterized in that: The sliding sleeve (35) has a receiving cavity (351) at one end near the injection port (341). When the sliding sleeve (35) covers the injection port (341), several of the guide baffles (36) are located inside the receiving cavity (351).

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