The Journal of Bone and Joint Surgery (American). 2006;88:56-60.
doi:10.2106/JBJS.F.00536
© 2006 The Journal of Bone and Joint Surgery, Inc.
Biophysical Stimulation with Pulsed Electromagnetic Fields in Osteonecrosis of the Femoral Head
Leo Massari, MD,
Milena Fini, MD,
Ruggero Cadossi, MD,
Stefania Setti, MSc and
Gian Carlo Traina, MD
Corresponding author: Leo Massari, MD Department of Biomedical
Sciences and Advanced Therapies, Orthopaedic Clinic, University of Ferrara,
Corso della Giovecca, 44100 Ferrara, Italy. E-mail address:
msl{at}unife.it
The authors did not receive grants or outside funding in support of their
research for or preparation of this manuscript. They did not receive payments
or other benefits or a commitment or agreement to provide such benefits from a
commercial entity. No commercial entity paid or directed, or agreed to pay or
direct, any benefits to any research fund, foundation, educational
institution, or other charitable or nonprofit organization with which the
authors are affiliated or associated.
Background: Osteonecrosis of the femoral head is the end point of a
disease process that results in bone necrosis, joint edema, and cartilage
damage. It leads to joint arthritis that necessitates total hip arthroplasty
in many patients. Because of its positive effects on osteogenesis and its
chondroprotective effect of articular cartilage, pulsed electromagnetic field
stimulation has been proposed as a method to prevent or delay the progression
of osteonecrosis.
Methods: A retrospective analysis of the results of treatment with
pulsed electromagnetic field stimulation of seventy-six hips in sixty-six
patients with osteonecrosis of the femoral head was performed. Patients with
Ficat stage I, II, or III osteonecrosis of the femoral head were treated with
pulsed electromagnetic field stimulation for eight hours per day for an
average of five months. Clinical and diagnostic imaging information was
collected at the start of the treatment and at the time of follow-up. The
primary end point analyzed was the avoidance of hip surgery, and the secondary
end point was limiting the radiographic progression (according to Ficat stage)
of osteonecrosis of the femoral head.
Results: Fifteen hips required a total hip arthroplasty; twelve of
these hips were in patients with Ficat stage-III disease. The need for total
hip arthroplasty was significantly higher in patients with Ficat stage-III
disease than in patients with Ficat stage-I (p < 0.0001) or II (p <
0.01) disease at the beginning of treatment. Pulsed electromagnetic fields
preserved 94% of Ficat stage-I or II hips. Furthermore, radiographic
progression (according to Ficat stage) occurred in twenty hips (26%). Pain,
present in all patients at the start of the treatment, disappeared after sixty
days of stimulation in thirty-five patients (53%) and was of moderate
intensity in seventeen patients (26%).
Conclusions: The results of this study confirm that pulsed
electromagnetic field treatment may be indicated in the early stages of
osteonecrosis of the femoral head (Ficat stages I and II). Pulsed
electromagnetic field stimulation may be able to either preserve the hip or
delay the time until surgery. The authors hypothesize that the short-term
effect of pulsed electromagnetic field stimulation may be to protect the
articular cartilage from the catabolic effect of inflammation and subchondral
bone-marrow edema. The long-term effect of pulsed electromagnetic field
stimulation may be to promote osteogenic activity at the necrotic area and
prevent trabecular fracture and subchondral bone collapse.
Level of Evidence: Therapeutic Level IV. See Instructions
to Authors on
jbjs.org for a
complete description of levels of evidence.

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