Page 169 - ASOP ROT Study Guide

Intramedullary, or inlay devices, are in many ways the most satisfactory method of fixation. They
achieve correct alignment of the broken bones without unduly disturbing natural bone healing.
They are a relatively inaccurate method of restoring anatomical position and so are not useful
around joints. Their great strength make them ideal devices for treating long bone fractures,
particularly in the lower limb.

If fractures are badly comminuted (fragmented) or rotated, then cross screws can be inserted in the
bone using an X-ray image intensifier to show the bone and nail during surgery. Such a technique
requires great skill and can only be performed where high technology is available.

The removal of implants

Whether internal fixation devices should be removed or not is a controversial issue. Following
fixation the bone next to a fixation device is relatively weaker as it shares the load with the fixation
device. This is because bone is alive and adapts constantly to loads applied to it. If the plate off-
loads the bone then that bone gets thinner than if it were not off-loaded. The adjacent
unsupported bone is normal. Thus a boundary is created between normal bone and weak, fixed
bone leading to stresses at the abnormal/normal bone interface. In the long term the biological risk
from implants is unknown. There are a number of disturbing reports of bone tumours arising
around implants late after implantation. This is not surprising when one considers the free ions and
radicals likely to be emitted from bone implants. It is probably safer therefore to remove implants
in young people, although there are risks involved in this procedure. Removal of a plate from
scarred wounds is by no means easy and complications, such as infection and damage to nerves
and blood vessels, may arise.

7.5.4 Traction

We have already discussed traction as a method of reduction of fractures but the term may also be
applied to a technique for holding a reduced position. The common use of the term traction is
unfortunate as there are only superficial similarities in its use in the two situations.

Using traction as a holding device involves the application of a relatively small weight to a limb,
which exerts a pull along the axis of the broken limb. This pull of at most 5 kilograms stimulates
muscles to contract. Muscles completely surround a bone, and this slight contraction (which is
really an increase in muscle tone), is sufficient to hold a broken bone in die position achieved at
reduction. Therefore traction in this situation is a holding and moulding device as the muscles
effectively "massage" the aligned fracture ends until natural healing takes place. This is in direct
contrast to traction in reduction where a relatively large force is used to overcome muscle
resistance to achieve alignment.

In practice traction can be applied in a number of ways:

♦ static
♦ dynamic
♦ balanced

Static traction

Static traction is used for relatively short periods where the pull is applied against another part of
the body. In the Thomas splint (Figure 26), the pull is applied against the ring which presses
against the pelvis.

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