Surgery – Instruments – Orthopedic instrumentation
Patent
1990-08-17
1991-12-24
Apley, Richard J.
Surgery
Instruments
Orthopedic instrumentation
606 57, 606 59, 606105, A61F 504
Patent
active
050748653
DESCRIPTION:
BRIEF SUMMARY
This invention relates to distraction apparatus for maintaining fractured joints during healing and has a principal, though by no means exclusive, application in the treatment of intra-articular fracture dislocations of the joints of the hand. Joint injuries often result in displacement of the internal components of the joint and of bone fragments which have become fractured and dislocated in the injury.
In the treatment of such injuries it is often required to create traction across a joint so that the components therof are retained in appropriate relative dispositions during the healing process. However, it is also advantageous in certain cases to permit gentle controlled movement of the joint which helps to mould the irregular surfaces and prevents eventual stiffness.
An object of the present invention is to provide a distraction apparatus for intra-articular phalangeal and metacarpo-phalangeal fractures, which is easy to apply with reduced operative time, is versatile to the extent that the degree of distraction may be easily changed during the healing process, and which allows slight movement at the site.
According to the present invention, there is provided distraction apparatus for maintaining fractured joints during healing, comprising at least two pins having parts for insertion into bone, one proximal to and the other distal to the injured site, with the remainder of the length of the pins projecting externally and generally normal to the axis through the site, and resilient means to determine and resiliently maintain the relative spacing of the inserted parts of the pins, thus to retain the components of the joint; characterised by a pair of resilient connecting members adapted for attachment externally and directly to and between the pins at spaced positions thereon.
Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:
FIG. 1 illustrates a pin forming part of the apparatus;
FIG. 2 is an enlarged view of one end of the pin shown in FIG. 1.
FIG. 3 is a similarly enlarged view of part of a connecting member forming part of the apparatus;
FIGS. 4 and 5 diagrammatically illustrate how the apparatus is applied to a finger joint; and
FIGS. 6 and 7 similarly illustrate how a modified form of the apparatus may be applied to an ankle injury and a tibial plateau injury respectively.
Referring to FIGS. 1 to 3, the apparatus essentially comprises a pair of highly purified stainless steel pins 10, some 98 mm in length and with a major part of its length approximately 2 mm in diameter. As can be seen particularly in FIG. 2, in one end region 11 of each pin its diameter is reduced to 1.5 mm over a length of some 10 mm from a tapered or conical end 12.
An undercut annular shoulder 13 is provided at the position spaced from the end 12 where the diameter of the pin 10 is reduced.
As will be described in relation to FIGS. 4 and 5, the length of the reduced diameter portion 11 will be selected according to the required depth of bone penetration, and the shoulder 13 prevents the pin from passing further through the bone.
Along the remaining length of each pin 10 at 1 cm intervals, its diameter is reduced by grooves 14 of approximately 0.5 mm depth.
FIG. 3 illustrates part of one of a pair of stainless steel wire springs 15 shaped in a serpentine manner presenting alternate narrow and wide sections 16 and 17 of 1.5 mm and 2.5 mm width respectively. Each spring 15 has some 8 turns throughout its length, and of the pair of springs provided in the apparatus one will be of a wire 1 mm in diameter whilst the other will be smaller at approximately 0.7 mm in diameter.
Referring now to FIGS. 4 and 5 the apparatus is applied, in this example to a fractured finger joint, by initially inserting the ends 12 of pins 10 into and through the bone, proximally and distally respectively to the injury site 18. In the example shown the reduced diameter portions 11 of the two pins are of different lengths so as to project fully through two different thicknesses
REFERENCES:
patent: 4869242 (1989-09-01), Galluzzo
"Biomechanics of Fracture Healing", Journal of Bone and Joint Surgery, p. 1049, vol. 37A#5, Oct. 1955.
Apley Richard J.
Dvorak Linda C. M.
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