RU49710U1 - UNIVERSAL INTRAMEDOLLAR FEM NAIL - Google Patents

Abstract

The utility model is aimed at expanding the possibilities of using a nail for various types of fractures of the femur (with different lengths of the distal fragment, with high and low fractures of the femur, as well as with unstable fractures). The specified technical result is achieved by the fact that the universal intramedullary nail has additional holes for locking screws: at the proximal end of the rod closer to the end of the nail there is a round hole and at the distal end of the nail there is an oval hole in the frontal plane located as close to the end of the nail as possible, with the end the nail is rounded. Round holes at the distal end of the nail are located in the anteroposterior and frontal planes.

Description

The utility model relates to traumatology, namely to intramedullary nails with blocking, and is intended for osteosynthesis of femoral fractures.

Known femoral nail without drilling (Tomas P. Ruedi, William M. Murphy, AO Principles of Fracture Management, Stuttgart-New York 2000, s.464), which is a rod made of titanium alloy with a diameter of 9, 10 and 11 mm, with holes for screws: two round holes (with a diameter of 5 mm) at the pointed end and one round and one oval hole (with a diameter of 5 mm) at the end of the rod attached to the conductor grip. After insertion, the nail is locked by inserting 4.9 mm screws into these holes, in the standard version, two screws at the proximal and distal ends of the nail. At the proximal end of the nail, one screw is inserted into the static (round) hole, the second into the dynamic (oval) hole, that is, after removing the screw from the round hole, fragments can come closer along the axis of the nail due to the screw sliding in the oval hole (dynamization).

The disadvantages of the known nail:

- limitation of the possibility of dynamization - it is possible only from the proximal side of the nail, which at high fractures dramatically reduces the stability of fixation of the central fragment and can lead to varus displacement;

- the inability to use a nail in distal fractures with a distal fragment length of less than 50-60 mm, since with a shorter fragment it will have only one screw, which does not provide stability.

- the inability to use a nail for fractures located above the subtrochanteric zone, since the static screw will be in the fracture line or distal to it.

- retrograde nailing (through the knee) is difficult

block in the proximal femur. In this area, it is difficult to remove the mediolateral holes on the screen of the X-ray image intensifier;

- in case of axis-unstable fractures after walking with a load, locking screw fractures are possible. Therefore, the load on the leg must be limited to the appearance of signs of fusion.

- the pointed end of the nail may perforate the articular surface with continued load after fracture of the locking screws.

The technical problem - expanding the possibilities of using a nail is solved as follows.

A universal intramedullary nail for the femur containing a titanium alloy rod with screw holes, with a round and oval holes at the proximal end of the nail, and two round holes at the distal, according to the technical solution, an additional round hole is made at the proximal end of the shaft, located closer to the end a nail, and at the distal end of the nail an additional oval hole is made in the frontal plane, located as close as possible to the end of the nail, round holes are made In the anteroposterior and frontal plane, the end of the nail is rounded.

The supply of nails with additional holes - round at the proximal end of the rod and oblong at the distal end - allows you to increase the number of locking screws to four from each end of the nail, and the location of the holes allows you to use screws in various combinations: to ensure stabilization of fragments at different lengths of the distal fragment, at low fractures when the canal in the distal fragment is short and wide.

In addition, when making an oval hole at the distal end of the nail, the nail can be dynamized not only by removing the screw

from a round (static) hole in the proximal but also in the distal end of the nail, which allows dynamization at high fractures of the thigh without threatening the stability of fixation of the central fragment.

The location of the oval hole as close as possible to the end of the nail (3 mm from the end of the nail) allows two locking screws to be inserted into the fragment with a height of only 20 mm.

It is possible to additionally insert a screw of a smaller diameter (4 mm) into the distal (oval) hole between two screws (6 mm in diameter), this allows you to create high angular stability regardless of the presence of bone fragments against each other, that is, even with the most unstable, fragmented fractures . The rounded end of the nail reduces the risk of perforation of the articular surface.

The location of the round holes at the distal end of the nail in different planes allows for retrograde insertion of the nail to proximal locking through a round hole made in the anteroposterior plane, which, when the patient is on the back, is much more conveniently displayed on the screen of the x-ray image intensifier than the holes in the frontal plane in the proximal femur.

Thus, the proposed design of the intramedullary nail expands the possibilities of its use: with different lengths of the distal fragment, with high and low fractures of the femur, as well as with unstable fractures.

Figure 1 presents a General view of the proximal end of a universal nail: A - prototype; B is the proposed nail.

Figure 2 presents a General view of the distal end of the universal nail: A - prototype; B - the proposed nail

Figure 3 presents the distal end of the universal nail for the femur with the inserted additional screw of a smaller diameter

between larger diameter screws.

The proposed universal intramedullary nail for the femur is a rod of titanium alloy with a proximal 1 end attached to the handle of the conductor (not shown in Fig.) And a distal 2 rounded end. The diameter of the rod can be 13 mm, 11.5 mm and 10 mm. At the proximal end 1, two round 3, 4 are made and between them there is one oval 5 hole with a diameter of 6 mm. An additional round 4 hole is located closer to the end of the nail. Screws 6 with a diameter of 6 mm are inserted into the hole: in round (static screws) and on both edges of the oval hole (on the lower edge - static, on the upper - dynamic). You can enter up to 4 screws.

At the distal 2 end of the nail there is an oval 7 hole in the frontal plane, and round 8, 9 holes in the anteroposterior and frontal planes. The diameter of the holes is 5 mm with a nail diameter of 10 mm, and 6 mm in nails with a diameter of 11.5 and 13 mm.

The lower edge of the oval 7 holes is located at a distance of 3 mm from the rounded end of the nail (in the prototype 20 mm); screw 6 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 makes it possible to stabilize more distal hip fractures than when using the prototype. In the distal (oval) hole between the two screws (6 mm in diameter), a screw 10 of a smaller diameter (4 mm) can additionally be inserted. Thus, up to 5 screws in various combinations can be inserted into the distal femur.

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 6 mm into the oval hole or two screws 6 mm and screw 4

mm into the distal hole (option with maximum angular stability);

- two 6 mm screws into the oval hole and a round screw in the anteroposterior plane;

- two screws 6 mm into the oval hole, screws into the round holes in the front-back and frontal plane;

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

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

- one static screw;

- one dynamic screw.

Nail dynamization is possible not only by removing the static screw at the proximal, but also at the distal end of the nail, because there is a dynamic (oblong) hole at both the proximal and distal ends of the rod, which allows dynamic high fractures of the thigh to be performed without threatening the stability of fixation of the central fragment.

With retrograde nail insertion, proximal locking is performed by inserting a screw into a circular hole in the anteroposterior plane, which, when the patient is placed on his back, is much more conveniently displayed on the screen of the x-ray image intensifier than holes in the frontal plane in the proximal femur. An increase in the diameter of the screws to 6 mm makes it possible not to limit the load on the leg immediately after osteosynthesis without fear of failure of fixation even in case of fractures without end stop of fragments.

Thus, the possibilities of using the proposed universal intramedullary nail significantly expand.

Claims (1)

A universal intramedullary nail for the femur containing a titanium alloy shaft with screw holes, with a round and oval holes at the proximal end of the nail, and two round holes at the distal, characterized in that an additional circular hole is made at the proximal end of the shaft, located closer to the end of the nail, and at the distal end of the nail, an additional oval hole is made in the frontal plane, located as close as possible to the end of the nail, round holes passing through front and rear and frontal planes, and the end of the nail is rounded.