The AO pinless external fixator (PEF) uses trocar tipped clamps to grip the
outer tibial cortex rather than pins to transfix it. Its main advantage is
to avoid further contamination of the medullary canal in open tibial fract
ures where a nail may subsequently be used. We tested the anatomical safety
of this device and its effect on plastic surgical procedures compared with
a standard unilateral external fixator (UEF).
The PEF and UEF were placed on two amputated limbs which were then dissecte
d. structures at risk were traced on ten cadaver limbs.
We found that important anatomical structures were endangered by the PEF an
d that safe zones could not always be defined. The UEF avoided these struct
ures. Plastic surgical approaches were made more difficult by the PEF which
imposed limitations on local flap design and endangered the arterial perfo
rators which supply them.
We conclude that safety is compromised by the PEF because margins for error
are small. It poses additional problems in soft tissue reconstruction and
highlights the need for co-operation between plastic surgical and orthopaed
ic teams in choice of fixation device. (C) 2000 Elsevier Science Ltd. All r
ights reserved.