Page 165 - ASOP ROT Study Guide

Modern casting materials
Plaster of Paris is relatively brittle, is messy and is very difficult to apply well! It is heavy and
awkward particularly for an elderly person and, as it takes up to three days to dry, it can be very
inconvenient. For these reasons stronger and lighter new materials have been developed.
These are based on glass fibers and polyurethane resin combinations. They are not so versatile
as plaster of Paris and so are used as secondary casts a week or two after the injury, once
swelling has settled. They make ideal cast braces (Figure 20).

https://www2.aofoundation.org/wps/portal/!ut/p/a0/04
_Sj9CPykssy0xPLMnMz0vMAfGjzOKN_A0M3D2D
Dbz9_UMMDRyDXQ3dw9wMDAwCTfULsh0VAX
c5ElM!/?basicTechnique=Fracture%20management%
20with%20limited%20resources&bone=Tibia&segme
nt=Shaft&showPage=redfix

FIGURE. DIAGRAM OF A SIMPLE CAST BRACE WITH HINGED KNEE AND FIXED FOOT.

7.5.2 EXTERNAL FIXATION

High energy fractures are associated with extensive soft tissue damage, which often results in
breaching of the skin or even loss of soft tissue. In such cases, because the blood supply is
severely damaged, it is important to have an initial phase of soft tissue healing. This means that
plaster splints are highly unsuitable because the wounds become inaccessible. Internal fixation is
hazardous because of ischemia (lack of blood), and wound contamination increases the risk of an
infection being introduced during surgery.
For these reasons a compromise must be sought. A device which is fixed to the bones by pins and

which stabilizes the limb by
means of an external scaffold,
has attractions. Such a device
(Figure 21) provides stability of the
bones and allows access to the
soft tissues for dressings and
secondary surgery such as skin
grafting.

FIGURE. TYPICAL EXTERNAL
FIXATOR ON A TIBIAL FRACTURE.