RU81636U1 - INTRAMEDOLLAR NAIL FOR TIBSA - Google Patents

Abstract

The utility model relates to traumatology, namely to intramedullary nails with blocking, and is intended for osteosynthesis of high periarticular fractures of the tibia. The intramedullary nail contains a rod of titanium alloy with a proximal end of a cylindrical shape which has three circular holes at an angle of 45 degrees to the frontal plane and 90 degrees to each other at different levels, and an oval hole and a distal rounded end with an oval hole in the frontal plane, and two round holes in the anteroposterior and frontal planes. The proximal bend is made at a distance of 65 mm from the proximal end of the nail near the oval hole. Up to 5 screws can be inserted into the proximal end of the nail: two into the oval and one into three round ones. Static screws (up to 4 screws) are inserted into the 45-degree holes and along the lower edge of the oval hole. Dynamic - along the upper edge of the oval hole. Up to 4 screws in various combinations can be inserted into the distal tibia. The achieved effect is an improvement in the fixation of high proximal fractures of the tibia.

Description

The utility model relates to traumatology, namely to intramedullary nails with blocking, and is intended for osteosynthesis of both periarticular and diaphyseal fractures of the tibia.

Known intramedullary tibial nail for periarticular fractures (utility model patent No. 63211, 2007), which is a rod with a proximal bend of a titanium alloy having round and oval screw holes at the proximal and distal ends: two round and oval holes at the distal rounded end and one oval hole and two round, made at an angle of 45 degrees in the frontal plane - at the proximal end with a bevel, while the proximal bend is made next to the oval hole .

However, the known intramedullary nail can ensure the stability of fixation of fragments with a proximal fragment length of more than 35 mm, and at higher proximal fractures of the tibia, it is rather difficult to achieve anatomical comparison of fragments, and with dynamization it is almost impossible to maintain stability of fixation of fragments. In addition, due to the shape of the proximal end of the shaft, there is a risk of fatigue fracture of the nail, and the bevel reduces the reliability of nail fixation with the conductor.

The technical task is to improve the fixation of high proximal fractures of the tibia: increase the fatigue strength of the fixator, improve the comparison of fragments at high fractures, improve the possibility of dynamization while ensuring stability of fixation is solved as follows.

In the intramedullary tibial nail containing

a titanium alloy rod with a proximal bend, at the ends of which round and oval holes for screws are made, and the proximal bend of the rod is located next to the oval hole, according to the technical solution, the proximal end of the nail has a cylindrical shape and there are oval and three round holes made under it angle of 45 degrees to the frontal plane and 90 degrees to each other at different levels.

The implementation of the proximal end of the rod of a cylindrical shape increases the fatigue strength of the intramedullary nail, which reduces the risk of fracture, in addition, there is room for a more proximal round hole. In addition, the cylindrical shape of the proximal end of the rod allows you to more reliably connect the nail with the conductor (necessary when introducing the nail). Three round holes located at an angle of 45 degrees to the frontal plane and at an angle of 90 degrees to each other at different levels provide stability of fracture fixation with the introduction of blocking screws at high proximal tibial fractures (proximal fragment length is 25 mm or more), maximizing the possibility of use of a nail for periarticular fractures.

Thus, the proposed intramedullary nail allows you to expand the possibility of its use in high periarticular fractures of the tibia, ensuring stability of fixation, while reducing the risk of fracture of the nail.

Figure 1 - presents a diagram of the proposed intramedullary nail.

The proposed intramedullary nail for the tibia is a titanium alloy rod with a proximal end (1) of a cylindrical shape and two grooves (2) for attachment to a conductor grip (not shown in Fig.) And a distal (3) rounded end. The diameter of the rod can be 13 mm, 11.5 mm and 10 mm. On

at the proximal (1) end, there are three round (4) holes and below them is one oval (5) hole. Three round (4) holes are made at an angle of 45 degrees to the frontal plane and at 90 degrees to each other at different levels. The center of the first round hole is located at a distance of 14 mm from the upper edge of the rod, the center of the second round hole is located at a distance of 22 mm from the proximal end of the nail, the center of the third round hole is located at a distance of 32 mm from the proximal end of the nail, the center of the rounding of the upper oval hole is at a distance 42 mm from the proximal end of the nail. Screws (6 mm in diameter) are inserted into the holes into round holes (static screws) and along both edges of the oval hole (static or dynamic). The proximal bend is made at a distance of 65 mm from the proximal end of the nail near the oval (5) hole. Up to 5 screws can be inserted into the proximal end of the nail: two into the oval and one into three round ones. Static screws (up to 4 screws) are inserted into the 45-degree holes and along the lower edge of the oval hole. Dynamic - along the upper edge of the oval hole.

At the distal end (3) of the nail, an oval (6) hole is made in the frontal plane, and round holes (7, 8) in the anteroposterior and frontal planes. The diameter of the holes is 5 mm with a nail diameter of 10 mm and 11.5 mm, and 6 mm in nails with a diameter of 13 mm. The lower edge of the oval hole is 3 mm from the rounded end of the nail; a screw can be inserted into this hole closer to the upper edge - as static, closer to the lower edge, as dynamic; two screws can be inserted into this hole, which wedges them, creates angular stability, that is, it allows stabilization of the most distal fractures. Thus, up to 4 screws in various combinations can be inserted into the distal tibia.

According to the increase in the length of the proximal fragment, the following main locking options are possible:

- two screws into the proximal 45 degree holes (with a fragment length of 25 mm),

- three screws in 45 degree holes (fragment length 35 mm),

- three screws into 45 degree holes and one screw along the upper edge of the oval hole (fragment length 45 mm),

- three screws into 45 degree holes and one screw along the lower edge of the oval hole (fragment length 55-60 mm or more).

For more distal fractures (diaphyseal fractures, fractures of the distal articular end), the proximal end of the rod is locked by traditionally introducing one dynamic screw along the upper edge of the oval hole, and one static screw in any round hole or along the lower edge of the oval.

The introduction of a larger number of screws provides greater stability at low fractures, when the channel in the distal fragment is short and wide.

Depending on the length of the distal fragment, the following main options for distal locking are possible (in increasing the length of the distal fragment):

- two screws in the oval hole (fragment length 15-25 mm),

- two screws an oval hole and a screw in a round hole in the front-rear direction (25-35 mm),

- two screws in the oval hole, screws in the round holes in the sagittal and frontal plane (more than 35 mm).

With more proximal fractures (diaphyseal, proximal), the following options are possible:

- two static screws (one in a circular hole, in the frontal plane, the other along the upper edge of the oval),

- two screws in the frontal plane - one static, the other dynamic,

- one static screw in any of the three holes,

- one dynamic screw in the oval hole.

Nail dynamization is possible not only by removing the static screw at the proximal, but also at the distal end of the nail, since there is a dynamic (oval) hole at both the proximal and distal ends of the nail, which allows dynamization at high fractures.

Thus, the use of the proposed intramedullary tibial nail provides better fragment matching with sufficient fixation stability at high periarticular fractures of the tibia, has higher fatigue resistance, and does not prevent fragments from converging along the axis after dynamization, which greatly expands the possibilities of its use.

Clinical example. Patient M. was admitted with fractures of the proximal metaphysis and distal diaphysis of the tibia. The length of the proximal fragment was 15 mm along the lateral side and 35 mm along the medial side.

Figure 2 presents the x-ray of the patient at admission (proximal fracture is shown by arrows).

Osteosynthesis was performed with the proposed intramedullary nail. The introduction of three static screws with a cross between them allowed for reliable three-plane fixation (Figure 3, Figure 4). After 3 months, Proximal fusion was achieved, proximal screws were removed to dynamize at the level of the distal fracture (Figure 5)

Claims (1)

An intramedullary tibial nail containing a rod of titanium alloy with a proximal bend, at the ends of which round and oval screw holes are made, and the proximal bend of the rod is located next to the oval hole, characterized in that the proximal end of the nail has a cylindrical shape and are located on it oval and three round holes made at an angle of 45 ° to the frontal plane and at an angle of 90 ° to each other at different levels.