WO1998037823A1

WO1998037823A1 - Skeletal traction clamp

Info

Publication number: WO1998037823A1
Application number: PCT/GB1998/000463
Authority: WO
Inventors: Muhammad Tahir Khan; Lang Yang; Michael Saleh
Original assignee: Muhammad Tahir Khan; Lang Yang; Michael Saleh
Priority date: 1997-02-28
Filing date: 1998-02-27
Publication date: 1998-09-03
Also published as: EP1011502A1; GB9704259D0

Abstract

A skeletal traction clamp (1) comprising a part circular, generally 'C'-shaped, support ring (2) subtending an angle greater than 180°, with the free ends (6) of the ring (2) each carrying a pin support (7), which is screw threaded to receive directly or indirectly a screw threaded pin having at an inner end a nose (15) adapted to engage a bone (17) and the pin (11) being manually adjustable inwardly and outwardly, with the pin support (7) being located at an obtuse angle with respect to the intended direction of traction (A).

Description

TITLE OF THE INVENTION

Skeletal Traction Clamp FIELD OF THE INVENTION

This invention relates to a skeletal traction clamp by which a bone is gripped for traction purposes, in the course of orthopaedic surgery. BACKGROUND OF TH E INVENTION Conventional practice in the treatment of relatively long bones such as a tibia or a femur has involved the use of transosseous pins or wires adapted to be passed transversely through the bone, via which pins or wires traction forces mav be transmitted to the bone Apart from the inevitable weakening of a bone or bone fragment by the need to drill a hole to accommodate the pin or wire, there is the major disadvantage in the potential for intramedullary spread of infection

into the bone interior, especially if followed by intramedullary fixation

OBJECT OF THE INVENTION

A basic object of the present invention is the provision of an improved skeletal traction

clamp that avoids the need for pins or wires passing through the bone and hence reduces the risk

of pin track osteomyelitis

SUMMARY OF THE INVENTION

According to the present invention there is provided a skeletal traction clamp comprising

a part circular, generally "C"-shaped, support ring subtending an angle greater than 180°, with

the free ends of the ring each carrying a pin support, which is screw threaded to receive directly

or indirectly a screw threaded pin having at an inner end a nose adapted to engage a bone and the

pin being manually adjustable inwardly and outwardly, with the pin support being located at an

obtuse angle with respect to the intended direction of traction.

Consequently, in use, the clamp in accordance with the invention is applied to a bone with the two pins screwed inwardly until the device satisfactorily engages the bone, either with no penetration of the cortex or possibly with some minimal penetration, as penetration of the cortex is largely inconsequential in the case of a bone such as a tibia 01 femur, with the engagement of course being satisfactory to transmit to the bone the particular level of traction loading that an orthopaedic surgeon wishes to apply

Irrespective of the precise circular or "C"-shape of the support ring, it is preferred that the

inside profile of the support ring is ti uly cnculai , whilst the support ring may be of non-constant thickness, being foi example of enlaiged thickness ovei a middle zone between the arms of the

In detail, although the ring may subtend an angle of 225°, oi thereabouts, preferably the

ring subtends an angle of 270°, or thei eabouts Furthermore, the obtuse angle of each pin support may be 1 15 oi 125 ° or theieabouts to the intended direction, or axis, of traction The

nose of each pin may have a sharpness angle of 45°, oi thei eabouts, to 90°, or thereabouts, with 45 ° being preferred

The pins diametei is pi efei ablv 6 mm oi thei eabouts In detail, each pin may be a two-

part pin, one part being an externally threaded pin body sciewed into its pin support with a leading end provided with a co-axial, blind, tapped hole, and the other part being a nose portion

having at one end a threaded spigot to sci ew into the blind bore, and at the other end a bone-

engaging and/oi peneti ating point, e g at 45 °

Examples of clamp in accordance with the i ention is shown in the accompanying

drawings, in which

Figui es 1 and 2 ai e views of two embodiments of clamp

Figure 3 is an enlarged diagiammatic view of the Figuie 2 type of clamp, and

Figure 4 is a further enlaiged, part-sectional view of one pin portion of a ring of Figures - J

1 to 3

In both embodiments like components are accorded like reference numerals

A skeletal traction clamp 1 comprises a part-circular, generally ^l C"-shaped support ring

2 subtending an angle greater than 1 80° In the embodiment of Figure 1 an angle of 225 ° is

indicated, whilst in the embodiment of Figures 2 and 3 an angle of 270° is indicated Each ring

2 comprises a pair of arms 3 and a middle zone 4, with each ring 2 having a circular, inner profile

5 with the middle zone 4 of enlarged thickness compared with the arms 3

A free end 6 of each ring carries a pin support 7 which, in the Figure 1 embodiment, is at

60° or thereabouts, with respect to the end 3, and in the Figure 2 and 3 embodiment, at 90° or

thereabouts

As best seen in Figure 4 each pin support 7 is externally screw threaded at 8, onto which

is screwed a socket end 9 of part 10 of a two part pin 1 1 The other end of part 10 is provided

with a blind tapped bore 12 into which is screwed a spigot 13 of the other part 14 of the pin 11

The other end of spigot 13 carries a nose 1 5, sharpened to a 45 ° conical angle, and adapted to

engage, with minimal penetration, the cortex 16 of a bone or bone part 17 requiring traction The

force of engagement is determined by the orthopaedic surgeon effecting manual screw adjustment

of the nose 1 5

After thus fitting a support ring 2, or a pair of spaced apart support rings 2, traction is

applied, by any suitable known means, in the direction of arrow A of Figures 1 and 2

Claims

1 A skeletal traction clamp compi ising a part circular, generally "C"-shaped, support ring subtending an angle greater than 180┬░, with the fiee ends of the ring each carrying a pin support, which is screw threaded, to l eceive dn ectly or indirectly a screw threaded pin having at

an inner end a nose adapted to engage a bone and the pin being manually adjustable inwardly and outwardly, with the pin support being located at an obtuse angle with respect to the intended direction of traction

2 A clamp as claimed in Claim 1 , whei ein the inside piofile of the support ring is truly circular

3 A clamp as claimed in Claim 1 or Claim 2 wheiein the support ring is of non-constant thickness, being of enlarged thickness ovei a middle zone between the arms of the ring

4 A clamp as claimed in any pi ecedmg claim w herein the ring subtends an angle of 225 ┬░

5 A clamp as claimed in any one of Claims 1 to 3 whei ein the ring subtends an angle of 270┬░

6 A. clamp as claimed in Claim 4, whei ein the obtuse angle of each pin support is 1 15┬░

7 ╬¢ clamp as claimed in Claim 5 whei ein the obtuse angle of each pm support is 125┬░

8 A clamp as claimed in any pi ecedmg claim, whei ein the nose of each pin has a

sharpness angle of 45 ┬░, or thei eabouts, to 90┬░, oi thei eabouts

9 A clamp as claimed in Claim 8, whei ein the shai pness angle is 45┬░

10 A clamp as claimed in any pi ecedmg claim, wheiein each pin is of 6mm diameter, or

thereabouts

1 1 A clamp as claimed in any pi ecedmg Claim, wherein each pin is a two-part pin, one

part being an externally thi eaded pin body screwed into its pm support, with a leading end provided with a co-axial, blind, tapped hole, and the other part being a nose portion having at one end a threaded spigot to screw into the blind bore, and at the other end a bone-engaging and/or penetrating point.

12. A skeletal traction system incorporating at least one clamp as defined in any one of

Claims 1 to 1 1