Either a full or a half pin are placed. Full pins are
mid-threaded and engage both the cis (near) and
trans cortex. Full pins connect to a fixation bar on
both sides of the bone. Half pins are end threaded
but also engage the cis and trans cortex however they
only connect to a bar on one side of the bone. ments to be fixated and are ideal for fractures close
to joint surfaces where there is not enough space for
other types of implants like plates and screws. Wires
offer a different type of stability, which enhances bone
healing through micro-movement of the fragments
and callus stimulation.
The advantages of full pins are increased stability to
the ESF construct, however they in crease soft tissue
damage and can only be used in the antebrachium
and distal brachium. Half pins provide less stability to
the construct but lead to less soft tissue damage and
can be used on almost any bone. Generally a con-
struct will have a mix of half and full pins to get the
best of both worlds. The general rule is they are not as rigid as pins and al-
most act as a mini trampoline for the fragment in sus-
pending the fragment in the circular ring as apposed
to fixating the fragment. For this reason is it general-
ly not recommended to place pins and wires in the
same fragment in a circular hybrid as the varying sta-
bility counteract each other and lead to loosening of
the implants.
A bare minimum of 2 pins should be placed per frag-
ment: One of these should be a full pin. Ideally 3 pins
should be placed per fragment. Each pin halves the
forces transferred through the other pins. This is true
up to 4 pins per fragment. More than 4 pins per frag-
ment provides little extra stability and one should
not exceed 4 pins per fragment. A minimum of 2 wires per fragment should be placed,
ideally 2 crossing wires with a further ‘drop’ wire
should be placed in a fragment for optimal stability.
Wires are generally smooth pins used in circular ring
fixators or circular hybrid fixators (Figure 3). They are
usually placed at 60 degrees to each other in a frag-
ment of bone and tensioned. They are then connect-
ed to a ring and combined with more rings or a hybrid
fixator in other fragments. The can have little stoppers
of metal on the pin which is tensioned against the
-trans cortex to limit loosening of the wire. These are
called olive wires. These wires allow very small frag-
Figure 1. Type II linear ESF
Pin Clamps
The improvement in the technology behind the pin
clamps is second only to the introduction of threaded
pins in the resultant massive decrease in complica-
tions associated with their use in ESF. The two sys-
tems that are essential to positive outcomes are the
SK Clamp™ by Imex and Securos Titan™ ESF clamp.
These are versatile and the bond between the pin and
the connecting bar is reliable. They have double and
single clamps to build any ESF construct your imagi-
nation can think up. Each company has a circular sys-
Figure 2. Linear ESF with an intramedullary pin tied in.
Issue 05 | OCTOBER 2017 | 13