GB2276549A

GB2276549A - Surgical knee fixator

Info

Publication number: GB2276549A
Application number: GB9305020A
Authority: GB
Inventors: Kevin Hardinge
Original assignee: Individual
Current assignee: Individual
Priority date: 1993-03-11
Filing date: 1993-03-11
Publication date: 1994-10-05
Also published as: GB9305020D0

Abstract

The fixator, for use in upper tibial osteotomy and total knee arthroplasty, comprises a foot support 1, a pair of upwardly extending spaced members 2, 3 pivotally connected to the foot support, and a base support 9 disposed beneath the foot support and adjustable relative thereto so that, in use, the leg may be held at a position to give a desired degree of knee flexion. The base support, which may be secured to the operating table by means of a bar 10, is formed as a ladder with each "rung" 11 of the ladder defining a slot which in use accommodates a downwardly dependant latching member 12 fixed to the underside of the foot support. Anterior connecting plates 14 and 15 may be provided for the attachment of vertical alignment rods. <IMAGE>

Description

A SURGICAL FIXATOR The present invention relates to a surgical fixator.

The fixator is intended particularly, but not exclusively, for use in the operations of upper tibial osteotomy and total knee arthoplasty. During such operations it is important that the patients leg be held securely in position to give a desired degree of knee flexion, without any undue pressure on any part of the leg and whilst allowing reasonable access thereto.

According to the present invention, there is provided a surgical knee flexure comprising a foot support, a pair of upwardly extending spaced members pivotally connected to the foot support, and a base support disposed beneath the foot support and adjustable relative thereto so that, in use, a patients leg may be held securely thereon at a position to give a desired degree of knee flexion.

In a preferred embodiment of the invention, the foot support is a plate and is provided with curved lateral edges and a curved posterior lip. The posterior lip is limited in height perhaps to 2 cms to avoid any undue pressure on the achilles tendon. The base support is formed as a ladder. Each "rung" of the ladder defines a shot which in use accommodates a downwardly dependant latching member fixed to the underside of the foot support. By choosing the appropriate rung the position of the plate relative to the base support may be altered and the degree of patient knee flexion with it. A bar is provided to hold the ladder in position on the operating table. The patients leg may be held in position between the two spaced members by means of connecting plates fixed to the members by turnbuckles.Each plate is generally horse-shoe shaped and the free ends are slotted to receive respective members. The fixator may be made of metal such as steel or aluminium of an alloy thereof or synthetic plastics 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 side elevational view of a surgical fixator according to the invention; Figure 2 is a diagrammatic end elevational partial view of the fixator of Figure 1; Figure 3 is a diagrammatic perspective view of part of the fixator of Figures 1 and 2 showing a modification; and Figure 4 shows a perspective view of part of the modification of Figure 3.

Referring to Figure 1, the surgical fixator comprises a foot plate 1 to which a pair of spaced side struts 2 and 3 (see Figure 3) are pivotally connected by means of respective pivots 4 and 5. The footplate 1, which is made of aluminium, an alloy, steel, synthetic plastics, or other suitable material is formed with curved side portions 6 and 7 (see Figure 3) and a curved posterior lip 8 approximately 2 cms in height. A ladder form member 9 is disposed beneath the footplate 1. This ladder form member 9 is secured to the operating table by means of a bar 10.

The member 9 comprises a plurality of spaced "rungs" 11. Each rung 11 is formed to accept a downwardly dependent latching member 12. By appropriate positioning of this member 12 in the ladder the position of the patients foot 13 on the operating table and there for in use the degree of flexion of the patients knee can be altered.

In the modification of Figure 3 upper and lower anterior connecting plates 14 and 15 are shown connected by retaining turnbuckles 16 and 17 to the struts 2 and 3. Each plate 14, 15 is substantially horse-shoe shaped, and is formed at each free end with a slot 18 to accommodate the corresponding strut.

In use the surgical fixator that may be used to facilitate the operations of upper tibial osteotomy (UTA) or total knee arthroplasty (TKA). The patients foot is stabilised in the foot plate 1 by the small posterior lip. This curves behind the heel but does not put pressure on the achilles tendon insertion into the oscalcis, being merely 2.0 cms in height and curving posteriorly. Attaching the foot plate 1 to the ladder 9 at an appropriate position stabilises the patients knee in flexion, freeing the surgical assistant to help with haemostosis thus markedly reducing the need for blood transfusion. As the knee is held the surgical assistant is also freed to assist in haemostosis so that TKA resembles the same order of magnitude as total hip arthroplasty with regard to haemostosis so that the surgeon can be encouraged to undertake TKA without using a tourniquet.Pivots 4 and 5 which are disposed at the ankle enabling the ankle joint to be manipulated during surgery thus pumping the deep calf veins reducing stasis with its unfavourable sequelae of thrombosis and embolus. The side struts 2 and 3 ensure that there is no direct pressure on the calf ths preventing or reducing stasis on the deep calf plexus of veins. The datum face of the upper tibial cut(s) can be taken from the anterior border of the tibia, malleoli and anterior tibial tubercle by direct palpation giving coronal, sagittal and axial alignment. The side struts 2 and 3 also ensure that the fixator can be used in a wide variety of lengths of leg as there is no posterior element that could potentially obstruct the popliteal fossa.

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 the curved anterior connecting plates 14 and 15 can be adapted for the attachment of vertical rods for the alignment of UTA and TKA. Advocate and Legent II in AMK series.

Claims

1. A surgical knee fixator comprising a foot support, a pair of upwardly extending spaced members pivotally connected to the foot support, and a base support disposed beneath the foot support and adjustable relative thereto so that, in use, a patients leg may be held securely thereon at a position to give a desired degree of knee flexion.

2. A surgical knee fixator as claimed in claim 1, wherein the foot support is plate.

3. A surgical knee fixator as claimed in claim 2, wherein the plate is provided with curved lateral edges.

4. A surgical knee fixator as claimed in claim 2 or 3, wherein the plate is provided with a curved posterior lip.

5. A surgical knee fixator as claimed in claim 4, wherein the posterior lip is limited in height.

6. A surgical knee fixator as claimed in claim 5 wherein the posterior lip is limited in height to 2 cms to avoid any undue pressure on the achilles tendon.

7. A surgical knee fixator as claimed in claims 1 to 6, wherein the base support is formed as a ladder.

8. A surgical knee fixator as claimed in claim 7, wherein each "rung" of the ladder defines a slot which in use accommodates a downwardly dependant latching member fixed to the underside of the foot support.

9. A surgical knee fixator as claimed in claims 7 or 8, wherein a bar is provided to hold the ladder in position on the operating table.

10. A surgical knee fixator as claimed in any of claims 1 to 9, wherein an anterior plate is attached to the two spaced members for the insertion of vertical alignment rods to aid in the selection of level of setion (cutting or osteotomy) in upper tibial osteotomy or total knee replacement.

11. A surgical knee fixator as claimed in claim 10, wherein the plate is semicircular.

12. A surgical knee fixator as claimed in claims 10 or 11 wherein each plate is generally horse-shoe shaped and the free ends are slotted to receive respective members.

13. A surgical knee fixator as claimed in any preceding claim, wherein the fixator is made of metal such as steel or aluminium or of an alloy thereof.

14. A surgical knee fixator as claimed in any of claims 1 to 12, wherein the fixator is made of synthetic plastics material.