passage 1
despite the countless advances in medicine over
the last hundred years, today's primary treatment for
broken bones remains largely identical to the treatment
used throughout human history. the reason for this is
simple: bones are excellent at healing themselves.
through a process that may last weeks or months, the
bone and surrounding cells return the broken bone to
its natural state.
immediately after a bone breaks, the
surrounding blood vessels begin to constrict, reducing
additional blood loss, and a blood clot forms around
the fracture site. loose blood cells, bone fragments,
and germs are restricted within the blood clot. cells
that collect and destroy threatening material begin to
clean the area. at this point, a doctor will set the
bone to ensure that the rest of the process goes well.
it takes a few days for the periostium, the
membrane that naturally surrounds the bone, to respond
to the break. the periostial cells closest to the
fracture begin to transform and merge into soft
cartilage at the fracture site. more distant periostial
cells become woven bone, which work their way toward
the fracture and merge with the soft cartilage. nearby
fibrous cells also transform into cartilage. before too
long, this soft cartilage forms a connection across
the fracture gap, uniting the bone with a somewhat soft
band known as a fracture callus.
the fracture callus takes on some of the
qualities of the nearby bone. most importantly, it
develops a mineral matrix which allows bone-building
cells known as osteoblasts to travel through it. the
many channels that run through the fracture callus soon
fill with osteoblasts, which meticulously line each
channel wall with bone. this phase lasts four to six
weeks. once complete, the bone reaches the stage in
which we usually consider it healed.
while the person who finally feels well may be
grateful to think that everything is complete once the
cast comes off, the body is not yet satisfied with its
own work. beneath the skin, a bulge of bone remains at
the fracture site. the body spends one to three years
dutifully breaking this bulky tissue down and replacing
it with compact bone so that it returns to
approximately the same shape it had initially.
although modern scientists know a great deal
more about the way that bones repair themselves than
scientists of a hundred years ago did, today's medics
still mostly treat fractures in the old fashioned way:
setting bones, making casts, and monitoring the
process. there is simply very little to be done to
improve the natural efficiency of the bone's healing
process.
passage 2
between five and ten percent of bone fractures
result in a phenomenon called "non-union," in which the
bones fail to mend by natural process. if the bone has
not begun mending 45 days after the fracture event, it
is considered a non-union case. therapies to overcome
this problem by encouraging union have proven effective
in many cases.
experiments conducted using electric energy to
overcome non-union began in 1821. at that time, a
british doctor named hartshorne attempted to treat a
broken bone by passing electric currents through the
fracture site. one other doctor experimented with
hartshorne's findings in the same century, but the work
remained largely ignored until 1953, when a new study
on rabbit bone growth stimulation using electricity was
published.
following the 1953 study, a variety of clinical
trials proved that electric currents helped stimulate
bone growth in non-union cases. in 1971, the electronic
therapy helped overcome non-union in a 51-year-old
lady. since then, the procedure has proven effective in
a small majority of cases. in 1994, the food and drug
administration of the united states of america approved
the medical use of electric bone growth stimulation to
treat fractures.
the key to this treatment's effectiveness is
not the application of electricity to the
bone itself, but the way the electricity
influences the cells surrounding the fracture. electric
currents encourage collagen production, mineralization
processes, and the speed with which the body
transports needed nutrients to the fracture site.
in addition to its effectiveness in non-union
cases, electricity has proven somewhat effective at
speeding the natural process of bone healing when
treatment begins at the time of the fracture. however,
the increase in speed is not considerable enough to
merit application to all broken bones, especially when
weighed against the additional time, effort, and
expense required to receive treatment.