CN218009915U - A internal fixation device that is used for total knee joint replacement postoperative Rorabeck II type fracture treatment - Google Patents

Abstract

The utility model discloses an internal fixation device that is used for total knee joint replacement postoperative Rorabeck II type fracture treatment, it contains: the main nail is provided with a plurality of first through holes at intervals at the near end, and the first through holes are matched with the bone screws to play a role in fixing; the far end of the main nail is provided with a spindle structure, a plurality of second through holes are arranged on the spindle structure in a crossed mode, and the second through holes are matched with the bone screws to achieve the function of cross fixing. The internal fixing device of the utility model effectively increases the anti-rotation capability and improves the fracture healing capability through the dual fixing design of the intramedullary oversleeve and the far and near end bone screws; the sleeve and spindle structure is adopted to realize that no extra skin incision is added, the operation is simple and easy to expose, the large-range soft tissue stripping is not needed, the operation wound is reduced, and the blood supply at the fracture end is protected; and the knee joint cavity does not need to be exposed during installation and use, thereby avoiding invasive operation in the joint and reducing postoperative complications such as knee joint adhesion stiffness and the like.

Description

An internal fixation for the treatment of Rorabeck type II fractures after total knee arthroplasty fixed device

technical field

The utility model belongs to the field of medical devices, in particular to an internal fixation device for treating Rorabeck type II fractures after total knee replacement.

Background technique

With the aging of the population, the incidence of bone and joint degenerative diseases is gradually increasing. Among them, the number of elderly people suffering from knee osteoarthritis is particularly large. Total knee arthroplasty (TKA) has been proven to be an effective treatment for end-stage elderly knee osteoarthritis. With total knee replacement surgery, patients can achieve pain relief, increase in joint mobility, and ultimately improve their quality of life. Although this surgical technique is very mature, due to the objective conditions of osteoporosis and poor bone quality in elderly patients, it is more common for patients to experience fractures around the knee joint after total knee arthroplasty. Once a periprosthetic fracture of the knee joint occurs, it will cause great damage to the patient itself and the function of the knee joint.

Periprosthetic fractures after total knee arthroplasty include distal femur fractures, proximal tibial fractures, and patella fractures according to the fracture site. Among them, distal femoral fractures are the most common, with an incidence of about 0.3-5.5%. The periprosthetic fractures of the distal femur can be divided into three types according to the stability of the prosthesis and the bone quality of the patient’s femur. Rorabeck type I fractures are non-displaced fractures with stable prosthesis (no prosthesis loosening) and good bone mass. (No displacement of the fracture end); Rorabeck type II fractures are displaced fractures with or without good bone mass, and the prosthesis is stable; Rorabeck type III fractures are prosthetic loosening or destruction, regardless of whether the fracture fragments are displaced or not. Among them, Rorabeck type II is the most common. The treatment principles of type I and type III distal femoral periprosthetic fractures have basically reached a consensus. Type I fractures are mainly treated conservatively, while type III fractures require total knee revision surgery. dispute.

At present, the main methods for the clinical treatment of Rorabeck type II distal femoral periprosthetic fractures mainly include locking plates and retrograde intramedullary nails. According to literature reports, the fracture union rates after treatment with locking plates and retrograde intramedullary nails are 87% and 84%, respectively. The complication rates were 35% and 53%, respectively, and the curative effects of both were not ideal. Not only that, the curative effect of locking plate will also be limited by the surgical approach, for example, it is difficult to solve the problem of medial condyle fracture with lateral locking plate. There are also studies that the fixation of the locking plate is too firm, resulting in a decrease in micromotion between the fractures, thereby increasing the risk of fracture nonunion. In addition, the current retrograde intramedullary nail system also has its limitations, including being easily restricted by the type of prosthesis (for example, the intercondylar box of the posterior stabilized knee prosthesis is closed or small, and the retrograde intramedullary nail cannot be inserted), Smaller distal fracture fragments or severe osteoporosis are not suitable for retrograde intramedullary nailing.

Utility model content

The purpose of the utility model is to solve the problem of effective treatment of Rorabeck type II fractures, provide an internal fixation device, and improve the clinical curative effect of Rorabeck type II fractures around the distal end of the femur.

In order to achieve the above object, the utility model provides an internal fixation device for the treatment of Rorabeck type II fractures after total knee arthroplasty, which comprises: a main nail, the proximal end of which is provided with several first through holes at intervals , the first through hole cooperates with the bone screw for fixation; the distal end of the main nail is provided with a spindle structure, and a plurality of second through holes are intersected on the spindle structure, and the second through holes cooperate with the bone screw for cross fixation effect.

Optionally, the fixing device is also provided with a sleeve, which is sleeved on the main nail and located between the first through hole and the spindle structure, the inner diameter of the sleeve matches the outer diameter of the main nail, It prevents the main nail from moving or rotating in the radial direction.

Optionally, the sleeve has a frusto-conical shape, and the outer diameter of the sleeve gradually decreases from the distal end of the main nail to the proximal end thereof.

Optionally, the outer surface of the sleeve is provided with a coating having a porous structure, and the pore size is 100-200 μm.

Optionally, in the coating, the pores communicate with each other, and the porosity is 55-65%.

Optionally, the thickness of the coating is 0.8mm-1.2mm.

Optionally, the distal end of the spindle structure is flat.

Optionally, the spindle structure is provided with at least two second through holes.

Optionally, the spindle structure is provided with 4 second through holes, two of which intersect each other.

Optionally, two second through holes are provided at the proximal end of the main nail.

The beneficial effects of the utility model:

1) Intramedullary sleeves and bone screws at the distal and proximal ends are double-fixed, which can effectively increase the anti-rotation ability and improve fracture healing ability;

2) The original surgical incision can be used without additional skin incision, which can effectively reduce the patient's pain, and the visual effect is more beautiful after recovery;

3) The exposure during the operation is simple and easy, does not require extensive soft tissue stripping, reduces surgical trauma, and protects the blood supply of the fracture;

4) There is no need to expose the knee joint cavity, avoid invasive operations in the joint, and reduce complications such as postoperative knee joint adhesion and stiffness.

Description of drawings

Fig. 1 is a structural schematic diagram of an internal fixation device of the present invention for the treatment of Rorabeck type II fractures after total knee arthroplasty.

detailed description

The technical solutions of the utility model will be clearly and completely described below in conjunction with the accompanying drawings. Apparently, the described embodiments are part of the embodiments of the utility model, but not all of them. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

In the description of the present utility model, it should be noted that the orientations or The positional relationship is based on the orientation or positional relationship shown in the drawings, which is only for the convenience of describing the utility model and simplifying the description, and does not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation , so it cannot be interpreted as a limitation of the present utility model. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and should not be construed as indicating or implying relative importance.

In the description of the present utility model, it should be noted that in medicine, the definition of far and near ends is: the side that is relatively close to the heart is called the near end, and the side that is far away from the heart, that is, closer to the extremities of the limbs, is called the far end. All relevant descriptions in the text are based on this. The distal end of the fracture refers to the side of the fracture that is far away from the fracture line and is closer to the extremity of the limb, and the distal end of the internal fixation device is the side closer to the extremity of the limb, and the two are consistent in direction.

In the description of the present utility model, it should be noted that, unless otherwise clearly stipulated and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection or a flexible connection. Detachable connection, or integral connection; it can be mechanical connection; it can be direct connection or indirect connection through an intermediary, and it can be the internal communication of two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present utility model in specific situations. For Rorabeck type II fractures, the femoral prosthesis is stable, and the fracture line is at the proximal end of the prosthesis, so a certain amount of bone is still preserved at the distal end of the fracture. For the treatment of Rorabeck type II fractures after total knee arthroplasty, the healing rate of locking plates and retrograde intramedullary nails is generally unsatisfactory, and the incidence of complications is high. The efficacy of locking plates is also limited by the surgical approach, and retrograde intramedullary nailing is also limited by the type of prosthesis.

The utility model hopes to use the original surgical incision as much as possible without adding additional skin incisions. The fixation device of the utility model is designed on the basis of the retrograde intramedullary nail structure, which can reduce the pain of the patient as much as possible. The design of the whole structure is mainly for the installation and fixation of the broken end of the fracture. The broken end of the fracture can be exposed through the knee incision in the original knee joint replacement surgery, and then installed and fixed, instead of adding more on the inner or outer side of the thigh like a steel plate. cutout for installation. The advantages of the incision are also available with ordinary intramedullary nails, but ordinary intramedullary nails need to be inserted from the joint cavity, but the utility model does not need to open the joint cavity, and is directly inserted from the fracture end, which can avoid complications such as postoperative knee joint adhesion and stiffness. disease.

As shown in Figure 1, a kind of internal fixation device used for the treatment of Rorabeck type II fracture after total knee arthroplasty of the present utility model comprises: main nail 10, and the proximal end of this main nail 10 is provided with several first through holes at intervals 11. The first through hole 11 cooperates with the bone screw 2 to fix the femur proximal to the fracture line; the distal end of the main nail 10 is provided with a spindle structure 12 . The spindle-shaped structure of the spindle structure 12 is designed based on the inventor's observation of the fracture ends of the femoral side of many cases of periprosthetic knee fractures and years of clinical practice experiments. On the one hand, it can achieve maximum contact with the distal residual bone , to increase the fixation effect. On the other hand, the spindle-shaped structure is conducive to the installation operation during the operation, and the obstruction of the femoral prosthesis can be avoided as much as possible during the installation. The spindle structure 12 is also provided with a number of second through holes 13 crossed, and the second through holes 13 cooperate with the bone screws 2 to form a cross fixation to the distal femur, mainly considering the amount of residual bone on the inside and outside of the distal femur in different patients. The difference is easy to operate and increases the fixed effect.

In some embodiments, the fixing device is further provided with a sleeve 14 , which is sleeved on the main nail 10 and located between the first through hole 11 and the spindle structure 12 . On the premise of not increasing the difficulty of surgical exposure, inserting the cuff 14 into the marrow can realize the radial stability of the main nail 10 and prevent the main nail 10 from moving or rotating in the radial direction. The inner diameter of the sleeve 14 is consistent with the outer diameter of the main nail 10, the main nail 10 is placed in the sleeve 14, and the position of the main nail 10 in the femoral medullary cavity can be ensured by utilizing the high fit of the shape and size of the two. At the same time, considering the abnormal shape of the femoral medullary cavity caused by osteoporosis in the elderly population, such as expansion, the sleeve sleeve can also play a certain role in shrinking the volume, otherwise the main nail will shake in the enlarged medullary cavity, which cannot be achieved quickly. Well stuck with the cortex.

Since the shape of the medullary cavity of the distal femur is a shape similar to a bell mouth, the proximal end is narrow and the distal end is wide, in order to increase the fit between the sleeve and the distal femoral cavity, in some embodiments, the sleeve 14 is cut The head is conical, and the outer diameter of the sleeve 14 decreases gradually from the distal end of the main nail 10 to the proximal end thereof.

In some embodiments, the outer surface of the sleeve 14 is provided with a coating with a porous structure (not shown in the figure), and the pore size is 100-200 μm. On the one hand, the purpose of designing the porous structure of the coating is to increase the coefficient of friction with the bone and improve the initial stability. On the other hand, it is hoped that the bone can grow into the porous structure to achieve biological fixation and increase long-term stability.

In some embodiments, in the coating, the pores communicate with each other, and the porosity is 55-65%, 60% in this example.

In some embodiments, the thickness of the coating is 0.8mm-1.2mm, 1mm in this example.

In some embodiments, the distal end of the spindle structure 12 is flat. The tip of the distal end of the spindle structure is cut off so that the end becomes flat, which is the "flat" as described herein. The flat structure design is based on the influence of the femoral prosthesis. The distal end is flat (flat). After cutting off the pointed end, the thicker part in the middle of the spindle structure can be placed in the bone, increasing the contact with the bone and improving stability. sex.

In some embodiments, the spindle structure 12 is provided with at least two second through holes 13 .

In some embodiments, the spindle structure 12 is provided with 4 second through holes 13 , two of which intersect each other.

In some embodiments, the proximal end of the main nail 10 is provided with two second through holes 13 .

The installation method of the internal fixation device provided by the utility model for the treatment of Rorabeck type II fractures after total knee replacement is as follows:

1. Using the incision of the original knee arthroplasty, extend it to the proximal end by 1-10 cm, without additional incision, and reduce the trauma of the patient;

2. Separate the subcutaneous tissue, enter the gap between the rectus femoris muscle and the vastus medialis muscle, and expose the fractured end after splitting the vastus intermedius muscle;

3. After cleaning the blood clot at the fracture end, lift up to expose the proximal end of the fracture, use a tapered drill to grind the proximal femoral medullary cavity of the fracture end, and implant the cuff 14;

4. Open the femur at the distal end of the fracture with a coarse electric drill. The diameter of the opening is consistent with the spindle structure 12 of the main nail. After putting the main nail in the sleeve 14, the fracture is reduced so that the spindle structure 12 is inserted into the distal opening;

5. After adjusting the rotational alignment of both ends of the fracture, place four fixed bone screws at the distal spindle;

6. X-ray examination of the alignment of the fracture end, after confirming that the alignment is good, the fracture end is properly pressurized, and two bone screws proximal to the main nail are placed, and the installation is complete.

In summary, the internal fixation device of the present invention not only has the natural advantages of intramedullary nails, such as less stripping of soft tissue, less damage to the blood supply around the fracture, and is helpful for fracture healing; The spindle structure can be inserted without cutting the joint cavity, and can be installed at the fracture end, which is very convenient and can avoid complications such as joint adhesion and stiffness caused by opening the joint; combined with the first pass at the proximal end of the main nail The design of the second through hole on the hole and the spindle structure, combined with the bone screw, can effectively increase the anti-rotation performance and improve the fracture healing ability.

Although the content of the present invention has been described in detail through the above preferred embodiments, it should be recognized that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions of the present utility model will be obvious to those skilled in the art after reading the above content. Therefore, the protection scope of the present utility model should be defined by the appended claims.

Claims (10)

1. An internal fixation device for the treatment of Rorabeck type II fractures after total knee arthroplasty, characterized in that the fixation device comprises: a main nail, the proximal end of the main nail is provided with some first through holes at intervals, the main nail The first through hole cooperates with the bone screw for fixation; the distal end of the main nail is provided with a spindle structure, and a plurality of second through holes are intersected on the spindle structure, and the second through holes cooperate with the bone screw for cross fixation. 2. the internal fixation device for Rorabeck type II fracture treatment after total knee arthroplasty as claimed in claim 1, is characterized in that, this fixation device is also provided with a sleeve, and it is sleeved on the main nail, Located between the first through hole and the spindle structure, the inner diameter of the sleeve matches the outer diameter of the main nail. 3. the internal fixation device for Rorabeck type II fracture treatment after total knee arthroplasty as claimed in claim 2, is characterized in that, described cuff is frusto-conical, from the distal end of main nail to its proximal end direction, the outer diameter of the sleeve gradually decreases. 4. the internal fixation device for Rorabeck II type fracture treatment after total knee arthroplasty as claimed in claim 2, is characterized in that, described cuff outer surface is provided with the coating with porous structure, and aperture size is 100 ~200μm. 5. the internal fixation device used for the treatment of Rorabeck II type fracture after total knee arthroplasty as claimed in claim 4, it is characterized in that, in the described coating, interconnected between hole and hole, porosity is 55- 65%. 6 . The internal fixation device for treating Rorabeck type II fractures after total knee arthroplasty as claimed in claim 4 , wherein the thickness of the coating is 0.8mm-1.2mm. 7. The internal fixation device for treating Rorabeck type II fractures after total knee arthroplasty as claimed in claim 1, wherein the distal end of the spindle structure is flat. 8 . The internal fixation device for treating Rorabeck type II fractures after total knee arthroplasty according to claim 1 , wherein the spindle structure is provided with at least two second through holes. 9 . The internal fixation device for treating Rorabeck type II fractures after total knee arthroplasty according to claim 1 , wherein the spindle structure is provided with 4 second through holes, which cross each other. 10. The internal fixation device for treating Rorabeck type II fractures after total knee arthroplasty as claimed in claim 1, wherein two second through holes are arranged at the proximal end of the main nail.

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