Biomedical Engineering Reference
In-Depth Information
and the whole stem can be irradiated homogeneously. PEMFs have been
used with success in patients with a loosened prosthesis and with a pri-
mary painful uncemented prosthesis [57]. In their randomized prospec-
tive double-blind study [56], Dallari et al. focused on the short-term effects
of PEMF stimulation after hip prosthesis revision. In fact, if a role has to
be identified for PEMF stimulation of the periprosthetic osteogenesis, the
effects should be observed in the early days after surgery. PEMF should be
used to increase spontaneous osseous regeneration, to limit inflammatory
response, to accelerate hip fixation, and to shorten the subject's functional
recovery time.
One limitation of the study is that only short-term results are reported.
Nevertheless, the initial fixation of the implant is crucial for the success of
prosthesis implantation [58]. Also, with strategies based on bisphosphonate
treatments that seem to decrease peri-implant bone loss, differences between
treated and control subjects have become evident after 3 months [58]. It has
also been shown that significant bone loss, up to 14%, occurs during the first
3 months after total hip arthroplasty [58].
Dallari et al. [56] indicated that, even though their double-blind study was
performed on a small but homogeneous group of subjects, they were able
to show the changes that occurred in bone after only 90 days, as well as
the positive effect of PEMF stimulation on BMD, on pain, and, consequently,
on functional recovery of subjects. The treatment was not associated with
any negative side effects; however, they noted that the use of this electro-
magnetic stimulation at the hip requires considerable subject commitment.
Nevertheless, they suggested that the use of PEMFs should always be con-
sidered after revision surgery, especially with severely loosened prostheses
and debilitated elderly subjects.
Finally, it is noted that many thousands of people around the world have
used PEMF successfully for a wide range of pain-related conditions. In fact,
PEMF influences cell behavior by inducing electrical changes around and
within the cell wall membrane.
In particular, pulsed electromagnetic wave field therapy creates ionic
migration of essential chemicals and proteins from cells into the blood-
stream by agitating the cell wall membranes; this subsequently encour-
ages the release of neurochemicals that occur naturally in the brain into the
bloodstream. These endorphins have powerful analgesic properties, as do
enkaphalins, an endorphin with opiate qualities that occurs in the brain.
PEMF also helps to enhance the cell utilization process in the body, which
in turn stimulates improved blood circulation, blood oxygen content, cell
growth, and blood vessel formation.
In bone fractures, affected tissues generate small electric charges that are
greater than those of less stressed matter, so osteoblasts (polarized bone-
laying cells) are attracted to these areas and begin to build up extra bone
material to counter the stress. PEMF encourages this process.
