Limb lengthening techniques harness the body’s ability
to heal itself through regeneration of bone and soft tissues
(e.g. skin, muscle, nerves, blood vessels, etc). The concept
of distraction osteogenesis involves the gradual pulling
apart (distraction) of a surgically cut bone, allowing
for the growth of new bone (osteogenesis) in the created
gap. That new bone hardens or consolidates and is as strong
as any other bone in the body.
This 9 year old girl had a 6 cm congenital shortening
of the right leg. Serial X rays over six months
demonstrating the stages of early distraction (A),
late distraction (B), consolidation (C) and healed
The first step in the process is cracking of the bone
to be lengthened through a small incision. The limb
is then stabilized by using one of a variety of external
and/or internal fixation devices. Most patients remain
in the hospital for one or two days, with physical therapy
beginning the day after surgery. Maintaining joint mobility
is a very important requirement during the distraction
(pulling apart) and lengthening of the bone that usually
begins five or ten days after surgery.
During the distraction phase, the cut in the bone is
gradually pulled apart through daily adjustments to
the fixator. As the space between the bones opens up,
the body continues to produce new bone in the gap until
the desired amount of bone is generated.
During the lengthening phase of treatment, patients
are x-rayed and examined every one to two weeks to evaluate
bone growth, nerve and muscle function and to have pin
sites examined for infection. After the desired length
of bone has been achieved and the limb has been straightened,
no further adjustments to the fixator need to be made.
During this consolidation phase, the fixator is left
in place to allow the new bone to harden and mature.
Once the new bone is completely healed, as confirmed
by x-rays, the fixation device is removed. This is done
as a same day procedure under general anesthesia. A
cast or brace is placed on the limb after the fixator
is removed for a few weeks in order to protect the bone.
Time in the fixator varies depending on the length
of bone growth needed. In general, the average time
in the fixator is one month per centimeter of bone lengthened
for children and about twice that period for adults.
This time encompasses both the distraction and consolidation