Clinical experience has proved that by this means
the mortality of primary amputations may be materially diminished,
especially in injuries necessitating removal of an entire limb.

Having decided to amputate, it is important to avoid having bruised,
torn, or separated tissues in the flaps, as these are liable to slough
or to become the seat of infection. In this connection it should be
borne in mind that the damage to soft tissues is always wider in
extent than appears from external examination.

The attempt to save a limb may fail and amputation may be called for
later because of spreading infective processes, osteomyelitis, or
gangrene; to prevent exhaustion from prolonged suppuration and toxin
absorption; or on account of secondary haemorrhage.

#Gun-shot Injuries of Bone.#--Fractures resulting from the impact of
bullet or fragments of shell are of necessity compound, and are
usually infected from the outset by organisms carried in by the
missile or by portions of clothing or other foreign material. Not
infrequently the missile lodges in the bone.

[Illustration: FIG. 7.--Excessive Callus Formation after infected
Compound Fracture of both Bones of Forearm--result of gun-shot wound.
Fusion of Bones across Interosseous Space.]

The extent of the injury to the bone varies infinitely, from a mere
chip or gutter-shaped wound to complete pulverisation of the portion
struck. The fracture is of the comminuted and fissured variety, the
cracks radiating from the point of impact and extending for a
considerable distance, sometimes even implicating the articular
surface of the bone some inches away. In comminuted fractures of the
shafts of long bones there is often a large wedge-shaped fragment
completely isolated from the rest, and in the presence of infection
this may form a sequestrum. Healing is often delayed by the separation
of sequestra, which takes place slowly, and union is attended with
excessive formation of callus. When a considerable section of the
shaft has been lost, want of union, fibrous union, or the formation of
a false joint may result.

The treatment is carried out on the same lines as in other forms of
compound fracture, except that mention should be made of the
irrigation method of Carrel, found to be the most potent means of
overcoming the associated infection.

SEPARATION OF EPIPHYSES[1]

[1] We do not employ the term "diastasis," which has been used in
different senses by different writers