CN216060708U

CN216060708U - Intramedullary nail for treating intertrochanteric fracture

Info

Publication number: CN216060708U
Application number: CN202121217296.4U
Authority: CN
Inventors: 张世民; 胡孙君; 杜守超; 熊文峰; 李世杰
Original assignee: Shanghai Yangpu Central Hospital
Current assignee: Shanghai Yangpu Central Hospital
Priority date: 2021-06-02
Filing date: 2021-06-02
Publication date: 2022-03-18
Anticipated expiration: 2031-06-02

Abstract

The utility model discloses an intramedullary nail for treating intertrochanteric fracture, and belongs to the technical field of intramedullary nails. The device comprises a thick rod part and a thin rod part which are connected up and down, wherein the thick rod part is sequentially provided with a first cylinder, a second cylinder and a conical part from top to bottom; the first cylinder and the second cylinder are connected up and down, the central axes of the first cylinder and the second cylinder are intersected, and the included angle is 3-20 degrees; the conical part is of a circular truncated cone structure with a large upper end face and a small lower end face, the upper end face of the conical part is overlapped and fixed with the bottom of the second cylinder, the lower end face of the conical part is overlapped and fixed with the top of the thin rod part, and the conical part is tightly abutted against the medullary cavity of the horn mouth. Compared with the existing intramedullary nail, on the one hand, the conical part direction is just opposite to the bellmouth medullary cavity through the second cylinder with increased deflection, on the other hand, the conical part is placed down through the second cylinder with extension, the conical part is tightly abutted against the bellmouth medullary cavity, and for the fracture between A3 type femoral trochanters, the stability of the intramedullary nail at the fracture line is better.

Description

Intramedullary nail for treating intertrochanteric fracture

Technical Field

The utility model relates to an intramedullary nail for treating intertrochanteric fracture, and belongs to the technical field of intramedullary nails.

Background

The intertrochanteric femoral fracture is coded as 31A in the AO/OTA fracture classification of 1996/2007 edition, wherein A1 and A2 are fractures with fracture lines along the intertrochanteric line (A1 is a simple type, and A2 is a comminuted type), and A3 is fractures with fracture lines along the reverse oblique type (31A.1), the transverse type (31A3.2) or the comminuted type (31A 3.3). The AO/OTA classification version 2018 has a larger change than that of 1996/2007, but the A3 classification does not change. The proximal side of the femur has a morphological structure, the inferior border of the lesser trochanter is the initial plane of the femoral medullary cavity, but the distal side of the inferior border of the lesser trochanter is 1-3cm (different according to height, male and female), belongs to a trumpet-shaped area of the opening of the proximal medullary cavity, and is wider. The A3 fracture between the trochanters of the femur belongs to the unstable type (unstable pattern) of primary fracture of the outer side wall, and the intramedullary nail therapy is the clinical choice. However, the current intramedullary nail has insufficient filling degree in the medullary cavity, is not firm for transfixion fracture of the lesser trochanter plane, and has much higher failure rate of the operation than the A1/2 type.

The existing intramedullary nail is used for drilling an oblique hole part of an endophyte into a femoral head, the outer inlets of the intramedullary nail are all on the plane of the middle point of a small trochanter, the thick part of the thick part extends 0.5-1cm far away from the oblique hole, namely the thick part of the near part of the intramedullary nail is not deep into a wide bellmouth medullary cavity below the small trochanter due to the insufficient length below the oblique hole, so that the filling degree of the intramedullary nail at a fracture end is insufficient, the A3 type fracture line is between the lower edge of the small trochanter and the initial plane of the femoral medullary cavity, a larger gap exists between the upper part of the intramedullary nail and the bellmouth medullary cavity, and after a period of operation, the intramedullary nail swings due to the stress of the fracture part, so that the stability of fracture fixation is poor, and internal fixation complications (bone nonunion, cutting of head and neck nails, fracture of the intramedullary nail and the like) due to insufficient stability are easy to occur.

Therefore, the intramedullary nail special for A3 type intertrochanteric fracture is designed, and the intramedullary nail can be tightly attached to the bellmouth medullary cavity by arranging the turning point, the cylindrical extension part and the conical part, so that looseness is prevented, and the stability of fracture fixation is improved.

Disclosure of Invention

The technical problem to be solved by the utility model is as follows: provides an intramedullary nail for treating intertrochanteric fracture, which solves the problems that the filling degree of the intramedullary nail used in the A3 intertrochanteric fracture is insufficient and the intramedullary nail is easy to swing.

The technical problem to be solved by the utility model is realized by adopting the following technical scheme:

an intramedullary nail for treating intertrochanteric fracture comprises a thick rod part and a thin rod part which are connected up and down, wherein the thick rod part is provided with a first cylinder, a second cylinder and a conical part from top to bottom in sequence;

the first cylinder and the second cylinder are connected up and down, the central axes of the first cylinder and the second cylinder are intersected, and the included angle is 3-20 degrees;

the conical part is of a circular truncated cone structure with a large upper end surface and a small lower end surface, the upper end surface of the conical part is overlapped and fixed with the bottom of the second cylinder, the lower end surface of the conical part is overlapped and fixed with the top of the thin rod part, and the conical part is tightly abutted against the medullary cavity of the horn mouth;

the first cylinder is provided with a through inclined hole;

the thin rod part is provided with a through interlocking screw hole.

As a preferred example, the upper end of the tapered part is 3.5-5cm away from the bottommost part of the inclined hole.

The utility model has the beneficial effects that: compared with the existing intramedullary nail, on the one hand, the conical part direction is just opposite to the horn mouth medullary cavity through the second cylinder with increased deflection, on the other hand, the conical part is placed through the second cylinder with extension, and the second cylinder is tightly propped against the horn mouth medullary cavity, so that for fracture between A3 type femoral trochanters, the stability of the intramedullary nail at the fracture line is better, the swing is not easy to occur, and complications such as bone nonunion, head and neck nail cutting, intramedullary nail fracture and the like after operation are avoided.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a classification chart of AO/OTA intertrochanteric fracture, version 1996/2007;

FIG. 3 is a 2018 version AO/OTA intertrochanteric fracture classification diagram;

FIG. 4 is a schematic structural view of an A3 intertrochanteric femoral fracture;

FIG. 5 is a schematic structural view of a prior art intramedullary nail;

FIG. 6 is a schematic view of a prior art intramedullary nail fixed in the medullary cavity;

fig. 7 is a schematic view of the present invention fixed in the medullary cavity.

In the figure: the femoral component comprises a thick rod part 1, a first cylinder 101, a second cylinder 102, a conical part 103, an inclined hole 104, an interlocking screw hole 105, a thin rod part 2, a bell mouth medullary cavity 3, a spiral blade 4, an interlocking screw 5, a lesser trochanter 6 and a femur 7.

Detailed Description

In order to make the technical means, the original characteristics, the achieved purpose and the efficacy of the utility model easy to understand, the utility model is further described with reference to the specific drawings.

As shown in figure 1, the intramedullary nail for treating intertrochanteric fracture of femur comprises a thick rod part 1 and a thin rod part 2 which are connected up and down, wherein the thick rod part 1 is provided with a first cylinder 101, a second cylinder 102 and a conical part 103 from top to bottom in sequence;

the first cylinder 101 and the second cylinder 102 are connected up and down, the central axes of the first cylinder and the second cylinder are intersected, and the included angle is 3-20 degrees;

the conical part 103 is in a circular truncated cone structure with a large upper end surface and a small lower end surface, the upper end surface of the conical part 103 is overlapped and fixed with the bottom of the second cylinder 102, the lower end surface of the conical part 103 is overlapped and fixed with the top of the thin rod part 2, and the conical part 103 is tightly abutted against the bellmouth medullary cavity 3;

the first cylinder 101 is provided with a through inclined hole 104;

the slender portion 2 is provided with a through interlocking screw hole 105.

The upper end of the conical part 103 is 3.5-5cm away from the bottommost part of the inclined hole 104.

As shown in fig. 2-3, the 7 trochanteric fracture of femur is encoded as 31A in the 1996/2007 version AO/OTA fracture classification, in which a1 and a2 are fractures with the fracture line running along the trochanteric line (a1 is simple and a2 is comminuted), and A3 is reverse oblique (31a.1), transverse (31A3.2) or comminuted (31A3.3) fractures with the fracture line running against the trochanteric line. The AO/OTA classification version 2018 has a larger change than that of 1996/2007, but the A3 classification does not change. The proximal side of the femur 7 has a morphological structure, the inferior margin of the lesser trochanter 6 is the initial plane of the medullary cavity of the femur 7, but the distal side of the inferior margin of the lesser trochanter 6 is 1-3cm (different according to height and male and female), belongs to a trumpet-shaped area of the opening of the medullary cavity of the proximal end, and is wider. The A3 fracture between the trochanters of femur 7 is an unstable type of primary fracture of the lateral wall (unstable pattern), the most clinically preferred intramedullary nail therapy. However, for the current intramedullary nail, for transfixion fracture of the lesser trochanter 6 plane, because the filling degree in the medullary cavity is not enough, the fixation is not firm, and the failure rate of the operation is far higher than that of the A1/2 type.

As shown in fig. 4, the fracture line of the A3 type fracture is between the inferior border of the lesser trochanter 6 and the starting plane of the medullary cavity of the femur 7, with a wide, bellmouth medullary cavity 3 below the lesser trochanter 6.

As shown in fig. 5 and 6, the existing intramedullary nail is driven into the femoral head at the position of the oblique hole 104 of the implant, the outer inlets are all on the plane of the midpoint of the small rotor 6, the thick section extends to the far side of the inclined hole 104 for only 0.5-1cm, namely, the thick part of the near section of the intramedullary nail can not go deep into the wide horn mouth medullary cavity 3 below the lesser trochanter 6 because of the insufficient length below the inclined hole 104, so that the filling degree of the intramedullary nail at the fracture end is insufficient, since the broken line of the A3 fracture is formed between the lower edge of the lesser trochanter 6 and the initial plane of the medullary cavity of the femur 7, and a large gap exists between the upper part of the intramedullary nail and the bellmouth medullary cavity 3, after a period of operation, because the fracture part is stressed, the intramedullary nail swings, so that the stability of fracture fixation is poor, and internal fixation complications (bone nonunion, head and neck nail cutting, intramedullary nail fracture and the like) are easy to occur due to insufficient stability.

As shown in fig. 7, when the intramedullary nail is installed, the thin rod part 2 is inserted into the medullary cavity, and the second cylinder 102 faces the conical part 103 to the bellmouth medullary cavity 3 and is compressed; the upper part of the intramedullary nail is fixed by a spiral blade 4 and/or a tension screw passing through the inclined hole 104 of the first cylinder 101; the interlocking screw 5 passes through the interlocking screw hole 105 of the slender rod part 2 to fix the lower part of the intramedullary nail, the upper part of the intramedullary nail is tightly abutted against the bellmouth medullary cavity 3, and the swinging is not easy to occur after the operation.

It has the following advantages: compared with the existing intramedullary nail, on one hand, the conical part 103 is just opposite to the horn mouth medullary cavity 3 through the second cylinder 102 with increased deflection, on the other hand, the conical part 103 is placed down through the second cylinder 102 with extension, and the conical part tightly leans against the horn mouth medullary cavity 3, for fracture between A3 type thighbone 7 rotors, the stability of the intramedullary nail at the fracture line is better, the swing is not easy to occur, and complications such as bone nonunion, head and neck nail cutting, intramedullary nail fracture and the like after the operation are avoided.

The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that various changes and modifications may be made without departing from the spirit and scope of the utility model as defined in the appended claims. The scope of the utility model is defined by the appended claims and equivalents thereof.

Claims

1. An intramedullary nail for treating intertrochanteric fracture comprises a thick rod part and a thin rod part which are connected up and down, and is characterized in that the thick rod part is provided with a first cylinder, a second cylinder and a conical part from top to bottom in sequence;

the conical part is of a circular truncated cone structure with a large upper end surface and a small lower end surface, the upper end surface of the conical part is overlapped and fixed with the bottom of the second cylinder, and the lower end surface of the conical part is overlapped and fixed with the top of the thin rod part;

the first cylinder is provided with a through inclined hole;

the thin rod part is provided with a through interlocking screw hole.

2. The intramedullary nail for treating intertrochanteric fractures according to claim 1, wherein the upper end of the tapered portion is 3.5-5cm from the lowermost portion of the oblique hole.