Implant for fixing posterior ligament avulsion fracture block

Abstract

The utility model provides an implant for fixing a posterior ligament avulsion fracture block, and belongs to the field of medical instruments. Comprising two pressing plates, namely a short pressing plate and a long pressing plate, the short pressing plate and the long pressing plate are connected through a coil, the short pressing plate and the long pressing plate are each provided with a coil hole for the coil to penetrate through, and supporting columns are arranged in the coil holes of the short pressing plate and the long pressing plate respectively. And meanwhile, the pressing plate can slide around supporting columns arranged on the short pressing plate and the long pressing plate. According to the utility model, the contact area between an implant and a bone block can be increased, and a small bone block is fixed together, so that a better long-term effect can be achieved after wound healing in the later period; after a bone block is fixed through the implant, original suture fixation and traditional steel plate screw fixation can be replaced, the contact area of the implant and the bone block is increased, the side effect of cutting caused by stress concentration of the screw and the suture on the local part of the bone block is avoided, and fixation is more reliable.

Description

Technical Field

[0001] This utility model relates to the field of medical devices, and in particular to an implant for fixing fragments of posterior cruciate ligament avulsion fractures. Background Technology

[0002] With the increasing incidence of traffic accidents and high-energy sports injuries, the chances of posterior cruciate ligament (PCL) injury have significantly increased. Among these injuries, tibial avulsion fracture of the PCL is a specific form of PCL injury and is relatively common clinically. A PCL avulsion fracture involves a fracture at the attachment point of the PCL in the knee joint. The mechanism involves direct force applied to the tibia during knee flexion, causing posterior displacement or hyperextension injury of the knee joint. The PCL, along with the tibial bone, is avulsed and displaced, leading to PCL laxity and failure. The PCL plays a crucial role in maintaining knee joint stability. The clinical presentation of a PCL tibial avulsion fracture is similar to that of a PCL rupture, resulting in knee instability. If displaced PCL tibial avulsion fractures are not treated promptly, they can lead to serious consequences such as malunion, nonunion, and accelerated knee degeneration. Surgical methods for treating PCL tibial avulsion fractures include arthroscopic surgery and open surgery. Fixation methods include plates, screws, anchors, and sutures. These methods are only applicable in specific situations. For example, plate and screw fixation is suitable for large bone fragment avulsions where the fragments are intact. However, in clinical practice, avulsed bone fragments are often of varying sizes. Screws and anchors themselves have a certain diameter (generally over 4mm). If the bone fragment is small, screwing in the screw may cause secondary cracking of the avulsed bone fragment, or even lead to unreliable fixation and surgical failure. Therefore, screw or anchor suture fixation has the following disadvantages: 1) It has certain limitations in applicable scenarios; 2) It requires screwing the screw into the bone fragment, which can cause secondary trauma to the patient, and the fixation effect is unreliable; 3) It is a single-point fixation, and the fixation effect is poor. In addition, anchor and suture fixation involves binding the avulsed bone fragment to the tibia together. Because the suture itself is thin, it is easy to cut the bone fragment. In addition, in order to ensure fixation strength, multiple turns are usually required, which increases the number of surgical steps and time. In addition, screws and sutures can also cause stress concentration. For example, when screws are used, the force is concentrated near the screw, and when sutures are used, the force is concentrated near the suture. Therefore, whether it is a point fixation such as a screw / anchor or a fine line fixation such as a suture, stress concentration will occur.

[0003] In addition, some patients with avulsion fractures exhibit varying fracture morphologies, with some smaller fragments that cannot be fixed simply with sutures. The only solution is to remove the smaller fragments and fix only the larger ones. However, fixing only the larger fragments results in incomplete bone morphology after fracture healing, leaving small gaps. Therefore, a new type of fixation device is particularly important. Utility Model Content

[0004] In view of this, the present invention aims to provide an implant for fixing posterior cruciate ligament avulsion fracture fragments, which can solve the problems of unreliable bone fragment fixation effect and stress concentration caused by existing suture fixation methods.

[0005] To achieve the above objectives, the technical solution of this utility model is as follows: An implant for fixing fragments of posterior cruciate ligament avulsion fractures includes two pressure plates, namely a short pressure plate and a long pressure plate, which are connected by a coil. The short pressure plate and the long pressure plate are respectively provided with coil holes for the coil to pass through. Support columns are respectively provided in the coil holes of the short pressure plate and the long pressure plate. The coil can not only pass through the coil holes of the short pressure plate and the long pressure plate, but also slide around the support columns provided on the short pressure plate and the long pressure plate.

[0006] Furthermore, the coil is a ring structure of fixed length.

[0007] Furthermore, the coil is a ring structure with an adjustable length.

[0008] Furthermore, the short pressure plate is shorter than the long pressure plate, and both the short and long pressure plates are made of PEEK material.

[0009] Furthermore, the coil hole is a through-hole structure that penetrates the upper and lower end faces of the short / long pressure plate.

[0010] Furthermore, suture holes are provided on both sides of the short pressure plate and the long pressure plate, and the suture holes are symmetrically arranged on the coronal surface of the short pressure plate / long pressure plate, and the suture holes are inclined on both sides of the short pressure plate and the long pressure plate.

[0011] Furthermore, all edges of both the short and long pressure plates are provided with rounded chamfers.

[0012] Furthermore, when the short pressure plate and the long pressure plate are connected together by a coil, the inclination direction of the sewing hole on the short pressure plate is the same as the inclination direction of the sewing hole on the long pressure plate.

[0013] Compared with existing technologies, the implant for fixing posterior cruciate ligament avulsion fracture fragments described in this utility model has the following advantages:

[0014] (1) This utility model can increase the contact area between the implant and the bone block, and reliably fix the small bone block, ensuring the stability of the fracture fragment after reduction in the early stage of fracture healing, and achieving better long-term effects in the later stage of healing.

[0015] (2) The implant described in this utility model can replace traditional suture fixation and rigid screw fixation for bone block fixation. It not only increases the contact area between the implant and the bone block, but also effectively avoids the stress concentration effect of the fixation device in the local area of ​​the bone block, reduces the occurrence rate of bone block cutting, and ensures the fixation effect of the surgery. Attached Figure Description

[0016] The accompanying drawings, which form part of this utility model, are used to provide a further understanding of the utility model. The illustrative embodiments of the utility model and their descriptions are used to explain the utility model and do not constitute an undue limitation of the utility model. In the drawings:

[0017] Figure 1 This is a schematic diagram of the structure of an implant for fixing avulsion fracture fragments of the posterior cruciate ligament, as described in an embodiment of this utility model.

[0018] Figure 2 A schematic diagram showing the suture passing through the implant described in this embodiment of the invention;

[0019] Figure 3 This is a schematic diagram of the structure of the short pressure plate described in an embodiment of the present utility model;

[0020] Figure 4 for Figure 3 Schematic diagram of the cross section of AA.

[0021] Explanation of reference numerals in the attached figures:

[0022] 1. Short pressure plate; 2. Long pressure plate; 3. Coil; 4. Sewing thread; 5. Coil hole; 6. Sewing thread hole; 7. Support column. Detailed Implementation

[0023] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0024] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] like Figures 1-4As shown, this invention is an implant for fixing posterior cruciate ligament (PCL) avulsion fracture fragments. Avulsion fragments at the PCL insertion point are generally irregular in shape or even pulverized. Due to the distribution characteristics of the ligament footprint area on the bone, the fracture fragments are mostly triangular or trapezoidal in shape. This invention includes two pressure plates: a short pressure plate 1 and a long pressure plate 2. The length of the short pressure plate 1 is shorter than the length of the long pressure plate 2, resulting in a one-to-one structural feature. The short pressure plate 1 and the long pressure plate 2 are connected by a coil 3, which is made of wire. Both the short pressure plate 1 and the long pressure plate 2 have coil holes 5 for the coil 3 to pass through. Supporting posts 7 are respectively installed within the coil holes 5 of the short pressure plate 1 and the long pressure plate 2. The coil 3 can not only pass through the coil holes 5 of the short pressure plate 1 and the long pressure plate 2, but also slide around the supporting posts 7 on the short pressure plate 1 and the long pressure plate 2. The support column 7 structure within the pressure plate allows the coil 3 to be bypassed by the support column 7, enabling the coil 3 and the pressure plate to be assembled with a simple structure. Suture holes 6 are respectively provided on both sides of the short pressure plate 1 and the long pressure plate 2. The suture holes 6 are symmetrically arranged on the coronal plane of the short pressure plate 1 / long pressure plate 2, and are inclined on both sides of the short pressure plate 1 and the long pressure plate 2. In practical applications, bone block fixation can be achieved by passing the binding suture 4 through the suture hole 6. In the description of this utility model, it should be understood that the terms "upper," "lower," "front," "rear," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0026] In different embodiments, coil 3 includes two structural forms: one is a ring structure with a fixed length; the other is a ring structure with an adjustable length.

[0027] like Figure 2 As shown, coil 3 is a fixed-length ring structure. During the operation, coil 3 does not need to be inserted into the short pressure plate 1 and the long pressure plate 2, nor does it need to be knotted, which can be implanted more quickly. In order to avoid the fixed-length coil 3 being affected by the size of the bone block, in practical applications, coil 3 of various specifications (i.e. coil 3 of different fixed lengths) can be provided to suit different patients.

[0028] like Figure 1 As shown, coil 3 is an adjustable-length ring structure. Medical staff can adjust coil 3 to the optimal length according to the shape of the avulsed bone fragment to suit the patient's needs. Because the length of coil 3 is adjustable, one size coil 3 can cover all patients. Compared to a fixed-length coil 3, this type of coil requires additional steps of knotting and adjustment.

[0029] Preferably, the short pressure plate 1 and the long pressure plate 2 are made of PEEK material, which can effectively avoid artifacts during subsequent X-ray examinations after the pressure plates are implanted.

[0030] The coil hole 5 is a through hole structure that penetrates the upper and lower end faces of the short pressure plate 1 and the long pressure plate 2.

[0031] Preferably, each edge of the short pressure plate 1 and the long pressure plate 2 is provided with a rounded chamfer, which can effectively prevent the pressure plate from causing cutting damage to the tissue or bone.

[0032] When the short pressure plate 1 and the long pressure plate 2 are connected together by the coil 3, the inclination direction of the sewing hole 6 on the short pressure plate 1 is the same as the inclination direction of the sewing hole 6 on the long pressure plate 2, which can prevent the coil 3 from folding and thus avoid cutting the coil 3.

[0033] It should be noted that the short pressure plate 1 and the long pressure plate 2 have the same structure, and the size and tilt angle of the sewing hole 6 are also the same. The difference between the two is that the length of the coil hole 5 and the overall outer dimensions of the pressure plate are different.

[0034] After the bone block is fixed by the implant described in this utility model, it can replace the original method of fixing with only sutures, increase the contact area between the implant and the bone block, avoid stress concentration and cutting of the bone block, and at the same time enhance the fixation effect.

[0035] In practical applications, when the implant described in this invention needs to be inserted, firstly, the procedure is performed in front of the posterior cruciate ligament (intercondylar fossa) in the anterior compartment of the arthroscopy. The two ends of suture 4 are pulled from the medial and lateral spaces of the posterior cruciate ligament to the posterior side of the posterior cruciate ligament (posterior mediastinal compartment), respectively. The tail ends of suture 4 are then pulled out of the body via the posteromedial approach of the arthroscopy for later use. The arthroscopy is existing technology.

[0036] Under arthroscopic monitoring behind the posterior cruciate ligament (posterior mediastinal compartment), avoiding the avulsed bone fragment, a tibial tunnel is prepared using a posterior cruciate tibial tunnel guide. The tunnel is prepared anteriorly and posteriorly through the tibia via the guide. The tunnel opening is located at an appropriate position on the medial and lateral sides of the distal end of the tibial bed of the avulsed bone fragment. In cross-section, the two bone tunnels form a certain angle, with a narrow anterior distance and a wide posterior distance. Then, a PDS guide suture is passed anteriorly and posteriorly through the bone tunnel for later use (this operation is performed on both bone tunnels). Subsequently, externally, the two sutures 4 extending from the posteromedial approach are passed through the suture holes 6 on both sides of the short pressure plate 1 and the long pressure plate 2, respectively. Figure 1 As shown. Then adjust the stitch 4 and loop 3 to the appropriate positions. Specifically, adjust them so that the stitch 4 and loop 3 do not cross or fold together. Then fold the short pressure plate 1 and the long pressure plate 2 in half (as shown). Figure 1As shown, after aligning the long sides, the implant is inserted into the implantation device, which is a prior art device. The implantation device is inserted through the posteromedial approach hole of the knee joint. After reaching the preset installation position, the implant is pressed onto the avulsed bone fragment using the implantation device. Finally, the double-tailed suture 4 on the implant is used to fix it, pulled out from back to front through the PDS guide lines of the two tibial tunnels on the medial and lateral sides, and tied in a knot at the front of the tibia. This completes the implantation of the implant described in this invention. The pressure plate consists of a short pressure plate 1 and a long pressure plate 2. Based on the shape of the bone fragment after the avulsion fracture, the long pressure plate 2 is attached to the side with the larger bone fragment, and the short pressure plate 1 is attached to the side with the smaller bone fragment. Because the pressure plates are all rounded, they will not cut or damage the tissue.

[0037] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An implant for fixing fragments of posterior cruciate ligament avulsion fractures, characterized in that: It includes two pressure plates, namely a short pressure plate (1) and a long pressure plate (2). The short pressure plate (1) and the long pressure plate (2) are connected by a coil (3). The short pressure plate (1) and the long pressure plate (2) are respectively provided with coil holes (5) for the coil (3) to pass through. The coil holes (5) of the short pressure plate (1) and the long pressure plate (2) are respectively provided with support columns (7). The coil (3) can not only pass through the coil holes (5) of the short pressure plate (1) and the long pressure plate (2), but also slide around the support columns (7) provided on the short pressure plate (1) and the long pressure plate (2).

2. The implant for fixing posterior cruciate ligament avulsion fracture fragments according to claim 1, characterized in that: The coil (3) is a ring structure of fixed length.

3. The implant for fixing posterior cruciate ligament avulsion fracture fragments according to claim 1, characterized in that: The coil (3) is a ring structure with adjustable length.

4. The implant for fixing posterior cruciate ligament avulsion fracture fragments according to claim 1, characterized in that: The length of the short pressure plate (1) is less than the length of the long pressure plate (2). At the same time, the short pressure plate (1) and the long pressure plate (2) are made of PEEK material.

5. An implant for fixing posterior cruciate ligament avulsion fracture fragments according to claim 1, characterized in that: The coil hole (5) is a through hole structure that penetrates the upper and lower end faces of the short pressure plate (1) / long pressure plate (2).

6. The implant for fixing posterior cruciate ligament avulsion fracture fragments according to claim 1, characterized in that: Suture holes (6) are provided on both sides of the short pressure plate (1) and the long pressure plate (2). The suture holes (6) are symmetrically arranged on the coronal surface of the short pressure plate (1) / long pressure plate (2), and the suture holes (6) are inclined on both sides of the short pressure plate (1) and the long pressure plate (2).

7. An implant for fixing posterior cruciate ligament avulsion fracture fragments according to claim 6, characterized in that: Each edge of the short pressure plate (1) and the long pressure plate (2) is provided with a rounded chamfer.

8. An implant for fixing posterior cruciate ligament avulsion fracture fragments according to claim 6, characterized in that: When the short pressure plate (1) and the long pressure plate (2) are connected together by the coil (3), the inclination direction of the sewing hole (6) on the short pressure plate (1) is the same as the inclination direction of the sewing hole (6) on the long pressure plate (2).

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