GB2273966A

GB2273966A - Staple for use e.g.in osteotomy

Info

Publication number: GB2273966A
Application number: GB9300068A
Authority: GB
Inventors: Kevin Hardinge
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-01-05
Filing date: 1993-01-05
Publication date: 1994-07-06
Also published as: GB9300068D0

Abstract

To allow the use of larger staples in osteotomy, each leg of the U-shape staple has a plane face 7, 8 which is at a non-parallel angle A to the bridge 5 of the U. The angle A lies between 30 and 60 DEG and is preferably 45 DEG . The staple is cast from a chrome-cobalt-nickel alloy. Gripping formations are provided on the legs and the bridge 5. <IMAGE>

Description

A STAPLE The present invention relates to a staple. The staple is intended particularly, but not exclusively, for use in osteotomy.

Staples for use in osteotomy are already known. In one such use in an osteotomy to correct a tibial deformity a wedge of bone is removed from the tibia and the cut faces of the bone held together by staples, which may be forged or stamped out, until healing can take place. To hold the faces together over a sufficiently large area a single large staple or number of smaller staples are sometimes used. In both cases, the legs of the staples are of square or rectangular cross-section and one side of the square or rectangle lies parallel to the cut faces which provide a reference. The plane or planes in which the pair or pairs of legs of the staple (in the case of a two legged or four legged staple respectively) lies or lie therefore extend at right angles to the cut faces.This tends to mean that the area of cut faces over which the staple extends and applies pressure is substantially equal to the extent of the staple along the cut faces. This in turn means that in order to increase this area, which is preferable in order to aidthe healing process a larger staple or more smaller staples are needed. One result of this is that after healing a second operation may be necessary in order to remove the larger staple or at least some of the smaller staples. It is an object of the invention to obviate these difficulties.

According to the present invention there is provided a staple comprising at least two legs joined by a bridge in which each leg has at least one plane face and one face of each leg is at an angle to the bridge.

In a preferred embodiment of the invention for use in osteotomy the staple is substantially U-shaped. The cross-section of each leg is square or rectangular. The angle of the face to the bridge lies between 300 and 600 and is preferably 450. The legs and/or bridge are provided with formations to improve purchase on and/or contact with the bone. The staple is made of a chrome-cobalt-nickel alloy or other suitable material.

In order that the invention may be more clearly understood, one embodiment thereof will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a diagrammatic view of a tibial osteotomy, Figure 2 is a plan view of an osteotomy staple according to the invention, and Figure 3 is a side elevational view of the staple of Figure 1.

Referring to Figure 1, the abutting cut faces of the osteotomy are referenced 1. After removal of the bone wedge to correct the deformity of the tibia the cut faces 1 are pushed together and held in that position by one or more staples shown diagrammatically at 2. These staples are placed at an angle to the cut faces. This increases the extent of the effect that the staples have along the cut faces 1 and therefore helps to promote healing of the bone. The angle of the staples 2 to the cut faces will advantageously lie between 300 and 60 , preferably 450.

The smaller the angle the smaller the pressure imposed by the staples. There is therefore a balance to be achieved between this pressure and its extent along the cut faces.

A staple 2 is shown to an enlarged scale in Figure 2. This comprises two legs 3 and 4 joined by a bridge 5.

The legs 3,4 and bridge 5 are provided with surface formations 6 to improve purchase/contact with the bone.

Each leg 3,4 is of square cross-section and is oriented to the bridge 5 so that when inserted in position across the cut faces 1 with a leg 3,4 inserted on opposite sides respectively of the cut faces into the bone the sides 7,8 of the legs adjacent the corresponding cut faces 1 are parallel to those faces. As the cut faces are used by the surgeon as a reference this facilitates accurate insertion of the staple. In the example shown the angle A of the legs 3,4 to the bridge 5 is 45 , but it may vary. This angle corresponds to the angle of the staple to the cut faces 1 when inserted. The staple is cast from a chrome-cobalt-nickel alloy or other suitable material.

Thus, in use, with the cut faces 1 held together the or each staple is aligned with the faces 7 and 8 parallel to the cut faces and the legs 3,4 on opposite sides respectively of the cut faces 1. The bridge then will be at an angle to those cut faces 1. A conventional introducer is employed to insert the staple into the bone. The design of the staple is such that usually only one or possibly two staples will be required. This reduces the necessity of a second operation to remove staples since their small size and number enables them to be left in place even after the bone has healed.

The or each staple is used in a relatively confined space and the amount of bone in the upper fragment, that is above the cut faces 1 in Figure 1, is often quite small. Putting in a staple "on the slant" means that it is possible to insert a bigger staple that will: (a) provide better and more secure fixation (b) apply greater pressure to promote healing of the osteotomy (c) be applied more closely to bone and reduce the necessity to remove as a second operation (d) apply a compressive force (the stimulant to healing) over a greater area than a staple disposed at right angles to the cut faces 1.

It will be appreciated that the above embodiment has been described by way of example only and that many variations are possible without departing from the scope of the invention. For example, instead of square section legs, rectangular or other sections may be used.

Claims

1. A staple comprising at least two legs joined by a bridge in which each leg has at least one plane face and one face of each Ig is at an angle to the bridge.

2. A staple as claimed in claim 1, which is substantially u-shaped.

3. A staple as claimed in claim 1 or 2, in which the cross section ot eacn leg is square.

4. A staple as clabrned in claim 1 or 2, in which the cross section of each leg is rectangular.

5. A staple as claimed in any preceding claim, in which the angle o the face to the bridge lies between 300 and 60 .

6. A staple as claimed in claim 5, in which the angle of the face to the bridge is 45 .

7. A staple as claimed in any preceding claim, in which formations are proved on the legs to improve purchase on and/or contact with the bone.

8. A staple as claimed in any preceding claim, in which formations are provided on the bridge to improve purchase on and/or contact with the bone.

9. A staple as claimed in any preceding claim, which is made of chrome-cobalt-nickel alloy.