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General
Bone Formation
Fracture Healing
Non-Union Fracture Healing
Pseudoarthrosis (formation of false joint)
Spinal Fusion
Osteonecrosis (death of bone cells)
Augmented bone-matrix formation and osteogenesis under magnetic field stimulation in vivo XRD, TEM and SEM investigations.
Singh P, YashRoy RC, Hoque M.
Biophysics and Electron Microscopy Section, Indian Veterinary
Research Institute, Izatnagar-243122, UP, India. psingh67@yahoo.com
Bone is a composite biomaterial, which is formed, when proteins
constituting collagen fibers attract calcium, phosphate and hydroxide
ions in solution to nucleate atop the fibers. It grows into a hard
structure of tiny crystallites of hydroxyapatite, aligned along the long
axis of collagen fibers. The present work reports the stimulating
effect of static magnetic field on microstructure and mineralization
process of bone repair. A unilateral transverse fracture of mid-shaft of
metacarpal was surgically created in healthy goats under thiopental
sedation and xylocaine analgesia. Two bar magnets (approximately 800
gauss/cm2 field strength) were placed across the fracture line at
opposite pole alignment immobilized in Plaster of Paris (POP) splint
bandage for static magnetic field stimulation. Radiographs were taken at
weekly intervals up to 45 days. Results show that formation of
extra-cellular matrix and its microstructure can be influenced by
non-invasive physical stimulus (magnetic field) for achieving an
enhanced osteogenesis, leading to quicker regeneration of bone tissue in
goats. X-ray diffraction (XRD) patterns of treated (magnetic
field-exposed) and control samples revealed the presence and orientation
of crystalline structures. Intensity of diffraction peaks corresponding
to 310 and 222 planes were enhanced with respect to 211 families of
reflections, indicating preferential alignment of the crystals. Also,
the percent crystallinity and crystal size were increased in treated
samples. The study provides a biophysical basis for augmented fracture
healing under the influence of semi-aligned static magnetic field
applied across the fracture line.
PMID: 16967906 [PubMed - indexed for MEDLINE]
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Fundamental and practical aspects of therapeutic uses of pulsed electromagnetic fields (PEMFs).
Bassett CA.
Department of Orthopedic Surgery, Columbia University, New York, New York.
The beneficial therapeutic effects of selected low-energy,
time-varying magnetic fields, called PEMFs, have been documented with
increasing frequency since 1973. Initially, this form of athermal energy
was used mainly as a salvage for patients with long-standing juvenile
and adult nonunions. Many of these individuals were candidates for
amputation. Their clearly documented resistance to the usual forms of
surgical treatment, including bone grafting, served as a reasonable
control in judging the efficacy of this new therapeutic method,
particularly when PEMFs were the sole change in patient management. More
recently, the biological effectiveness of this approach in augmenting
bone healing has been confirmed by several highly significant
double-blind and controlled prospective studies in less challenging
clinical circumstances. Furthermore, double-blind evidence of
therapeutic effects in other clinical disorders has emerged. These data,
coupled with well-controlled laboratory findings on pertinent
mechanisms of action, have begun to place PEMFs on a therapeutic par
with surgically invasive methods but at considerably less risk and cost.
As a result of these clinical observations and concerns about
electromagnetic "pollution", interactions of nonionizing electromagnetic
fields with biological processes have been the subject of increasing
investigational activity. Over the past decade, the number of
publications on these topics has risen exponentially. They now include
textbooks, speciality journals, regular reviews by government agencies,
in addition to individual articles, appearing in the wide spectrum of
peer-reviewed, scientific sources. In a recent editorial in Current
Contents, the editor reviews the frontiers of biomedical engineering
focusing on Science Citation Index methods for identifying core research
endeavors. Dr. Garfield chose PEMFs from among other biomedical
engineering efforts as an example of a rapidly emerging discipline.
Three new societies in the bioelectromagnetics, bioelectrochemistry, and
bioelectrical growth and repair have been organized during this time,
along with a number of national and international committees and
conferences. These activities augment a continuing interest by the IEEE
in the U.S. and the IEE in the U.K. This review focuses on the
principles and practice behind the therapeutic use of "PEMFs". This term
is restricted to time-varying magnetic field characteristics that
induce voltage waveform patterns in bone similar to those resulting from
mechanical deformation. These asymmetric, broad-band pulses affect a
number of biologic processes athermally. Many of these processes appear
to have the ability to modify selected pathologic states in the
musculoskeletal and other systems.
Crit Rev Biomed Eng. 1989;17(5):451-529.
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Effects of static magnetic and pulsed electromagnetic fields on bone healing.
Darendeliler, M., Darendeliler, A., & Sinclair, P.
The effect of static magnetic fields and pulsed electromagnetic
fields on bone healing in guinea pigs was investigated. The static
magnetic fields were produced using neodymium magnets, and the magnetic
field strengths that the guinea pigs were exposed to averaged about 500
gauss. The study concluded that "both static and pulsed electromagnetic
fields seemed to accelerate the rate of bone repair when compared to the
control group."
International Journal of Adult Orthodontic and Orthognathic Surgery, 1997;12, 43-53.
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Strong static magnetic field stimulates bone formation to a definite orientation in vitro and in vivo.
Kotani H, Kawaguchi H, Shimoaka T, Iwasaka M, Ueno S, Ozawa H, Nakamura K, Hoshi K.
Department of Biomedical Engineering, Graduate School of Medicine, University of Tokyo, Japan.
The induction of bone formation to an intentional orientation is a
potentially viable clinical treatment for bone disorders. Among the many
chemical and physical factors, a static magnetic field (SMF) of tesla
order can regulate the shapes of blood cells and matrix fibers. This
study investigated the effects of a strong SMF (8 T) on bone formation
in both in vivo and in vitro systems. After 60 h of exposure to the SMF,
cultured mouse osteoblastic MC3T3-E1 cells were transformed to rodlike
shapes and were orientated in the direction parallel to the magnetic
field. Although this strong SMF exposure did not affect cell
proliferation, it up-regulated cell differentiation and matrix synthesis
as determined by ALP and alizarin red stainings, respectively. The SMF
also stimulated ectopic bone formation in and around subcutaneously
implanted bone morphogenetic protein (BMP) 2-containing pellets in mice,
in which the orientation of bone formation was parallel to the magnetic
field. It is concluded that a strong SMF has the potency not only to
stimulate bone formation, but also to regulate its orientation in both
in vitro and in vivo models. This is the first study to show the
regulation of the orientation of adherent cells by a magnetic field. We
propose that the combination of a strong SMF and a potent osteogenic
agent such as BMP possibly may lead to an effective treatment of bone
fractures and defects.
J Bone Miner Res. 2002 Oct;17(10):1814-21.
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Use of physical forces in bone healing.
Nelson FR, Brighton CT, Ryaby J, Simon BJ, Nielson JH, Lorich DG, Bolander M, Seelig J.
Henry Ford Hospital, Detroit, MI, USA.
During the past two decades, a number of physical modalities have
been approved for the management of nonunions and delayed unions.
Implantable direct current stimulation is effective in managing
established nonunions of the extremities and as an adjuvant in achieving
spinal fusion. Pulsed electromagnetic fields and capacitive coupling
induce fields through the soft tissue, resulting in low-magnitude
voltage and currents at the fracture site. Pulsed electromagnetic fields
may be as effective as surgery in managing extremity nonunions.
Capacitive coupling appears to be effective both in extremity nonunions
and lumbar fusions. Low-intensity ultrasound has been used to speed
normal fracture healing and manage delayed unions. It has recently been
approved for the management of nonunions. Despite the different
mechanisms for stimulating bone healing, all signals result in increased
intracellular calcium, thereby leading to bone formation.
J Am Acad Orthop Surg. 2003 Sep-Oct;11(5):344-54.
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Bone Formation
Effect of some electric signals transmitted by an induction coil on
weight increase, incorporation of marker, and histological and
ultrastructural appearance of the skeleton in a chick embryo.
Duriez R, Bassett A.
Embryo Chicks were exposed to various types of electrical impulses
transmitted by induction coils between the 6th and 13th day of
incubation. Compared with controls, the Chick tibias showed a highly
significant increase in weight and length as well as increased
incorporation of tritiated thymidine. In addition, the total weight of
the treated embryos was significantly greater than that of the controls.
The results suggest that the effects of these electro-magnetic fields,
particularly their skeletal effects, act principally on cellular
multiplication and/or enhanced cellular activity following an increase
in protein synthesis.
C R Seances Acad Sci D. 1980 Jun 23;290(23):1483-6.
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Effects of static magnetic field on bone formation of rat femurs.
Yan QC, Tomita N, Ikada Y.
Institute for Frontier Medical Sciences, Kyoto University, Japan.
Effects of static magnetic fields (SMF) on bone formation of rat
femurs, were evaluated using tapered rods made of magnetized and
unmagnetized samarium cobalt of the same size. They were implanted
transcortically into the middle diaphysis of rat femurs under press-fit
loading. The bone mineral density (BMD) and bone calcium content were
measured 12 weeks after implantation by dual-energy X-ray absorptiometry
and chemical analysis with o-cresolphthalein complexon, respectively.
The result revealed that the femurs adjacent to magnetized specimens had
significantly higher BMD and calcium content than those adjacent to the
unmagnetized specimen (p < 0.01). However, the value of BMD and
calcium content of rats with magnetized specimens was similar to that of
non-operated rats. No specific change was found in the body weight,
serum Ca, activity of alkaline phosphatase, hemogram, and BMD of the
tibia and humerus among the magnetized and unmagnetized. These results
suggest that the long-term local SMF stimulation on the bone has a local
effect to prevent the decrease in BMD caused by surgical invasion or
implantation.
Med Eng Phys. 1998 Sep;20(6):397-402.
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Static magnetic field effects on bone formation of rats with an ischemic bone model.
Xu S, Tomita N, Ohata R, Yan Q, Ikada Y.
Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan.
Effects of a static magnetic field were studied on bone formation
using an ischemic rat femur model. Metal rods were prepared from
magnetized and unmagnetized samariun cobalt to have tapered structure,
both with the same geometrical dimension, and were implanted
transcortically into the middle diaphysis of 88 rat femurs. Both sides
of the rat femoral artery were ligated to create an ischemic bone model,
followed by implantation of the tapered rod to the femur. The bone
mineral density (BMD) and weight of the femurs were measured at 1st and
3rd week after implantation.The result at the 3rd week post-implantation
revealed that the BMD and weight of the ischemic bone model rats were
significantly reduced, compared with that of non-operated femur. It was
also found that the magnetized group had significantly higher bone
weights than the unmagnetized (p<0.05). The BMD of the rats implanted
with the magnetized rods were similar to those of the non-operated
(p>0.05). This enhancement of the femoral bone formation of the
ischemic rat model by the static magnetic field seems to be due to the
improved blood circulation of the femur.
Biomed Mater Eng. 2001;11(3):257-63.
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Effects of pulsed electromagnetic field stimulation on distraction osteogenesis in the rabbit tibial leg lengthening model.
Fredericks DC, Piehl DJ, Baker JT, Abbott J, Nepola JV.
Bone Healing Research Laboratory, Department of Orthopaedic Surgery,
University of Iowa College of Medicine, Iowa City, Iowa 52242, USA.
douglas-fredericks@uiowa.edu
The purpose of this study was to determine whether exposure to pulsed
electromagnetic field (PEMF) would shorten the healing time of
regenerate bone in a rabbit tibial distraction model. Beginning 1 day
after surgery, mid-shaft tibial osteotomies, stabilized with external
fixators, were distracted 0.25 mm twice daily for 21 days and received
either no exposure (sham control) or 1 hour per day exposure to
low-amplitude, low-frequency PEMF. Tibiae were tested for torsional
strength after 9, 16, and 23 days post-distraction. PEMF-treated tibiae
were significantly stronger than shams at all three time points. By 16
days post-distraction, the PEMF group had achieved biomechanical
strength essentially equivalent to intact bone. Shams did not achieve
normal biomechanical strength even after 23 days post-distraction. In
this tibial distraction model, short daily PEMF exposures accelerated
consolidation of regenerate bone. Clinical usefulness awaits testing.
J Pediatr Orthop. 2003 Jul-Aug;23(4):478-83.
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Effects of static magnetic fields on bone formation in rat osteoblast cultures.
Yamamoto Y, Ohsaki Y, Goto T, Nakasima A, Iijima T.
Departments of Orthodontics.
Although the promotional effects on osteoblasts of pulsed
electromagnetic fields have been well-demonstrated, the effects of
static magnetic fields (SMF) remain unclear; nevertheless, magnets have
been clinically used as a 'force source' in various orthodontic
treatments. We undertook the present investigation to study the effects
of SMF on osteoblastic differentiation, proliferation, and bone nodule
formation using a rat calvaria cell culture. During a 20-day culture,
the values of the total area and the number and average size of bone
nodules showed high levels in the presence of SMF. In the matrix
development and mineralization stages, the calcium content in the matrix
and two markers of osteoblastic phenotype (alkaline phosphatase and
osteocalcin) also showed a significant increase. Accordingly, these
findings suggest that SMF stimulates bone formation by promoting
osteoblastic differentiation and/or activation.
J Dent Res. 2003 Dec;82(12):962-6.
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Fracture Healing
Treatment of wrist and hand fractures with natural magnets: preliminary report
Costantino C, Pogliacomi F, Passera F, Concari G.
The Authors, after having defined the phenomenon and the biological
characteristics of natural magnets, evaluate their ability in
accelerating the formation of bone callus in hand and wrist fractures
compared to treatment with immobilization in a plaster cast. Forty
patients (4 females and 37 males) between 20 and 86 years of age were
treated. A small natural magnet was inserted in each of the plaster
casts (diameter: 2cm, height: 0.5cm) made of 4 blocks in
Neodymium-Iron-Boron, capable of generating 4 magnetic poles (2 positive
and 2 negative) of diagonal alternate polarity that produced a
symmetric, quadruple static magnetic field. The created magnetic flow
was wavelike, concentrated in one direction, and developed a force up to
12,500 gauss. From this study it has emerged that inserting a quadruple
magnet in a plaster cast in hand and wrist fractures results in the
formation of bone callus in an average time that is 35% inferior [shorter]
to the standard time. Accelerating the healing of the fracture is
important since it reduces immobilization time for the joints involved,
avoiding subsequent weakness and stiffness and allowing the patient to
begin rehabilitative physiotherapy sooner, which permits a faster
functional recovery.
Acta bio-medica: Atenei Parmensis 2007 Dec;78(3):198-203. PMID: 18330079
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Modification of fracture repair with selected pulsing electromagnetic fields.
Bassett CA, Valdes MG, Hernandez E.
We assayed different pulsing electromagnetic fields for their effects
on the mechanical and histological repair properties of an osteotomy of
the radius of the rat fourteen days postoperatively. Highly significant
differences were found in the control and experimental initial load
values and their decay as a function of time. These results correlate
well with the histological pattern in the bridging callus. A pulse that
produces an increase (above the control level) in initial load by a
factor of 2.4 and a slower decay was characterized by more extensive
calcification of fibrocartilage and its replacement by fibrous bone at
this early, but important, stage in fracture-healing.
J Bone Joint Surg Am. 1982 Jul;64(6):888-95.
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Effect of a static magnetic field on fracture healing in a rabbit radius. Preliminary results.
Bruce GK, Howlett CR, Huckstep RL.
To ascertain what effect a static magnetic force has on a healing
fracture, samarium cobalt magnets were implanted adjacent to induced
radial fractures in adult rabbits. A magnetic field of 220-260 G was
generated at the fracture site. The radii were allowed to heal for four
weeks and the contralateral fractured bones acted as controls. Healing
bone units were assessed microscopically and mechanically. Significantly
greater forces (p less than 0.01) were required to break those bone
units exposed to magnetic fields. However, no significant difference was
found when comparing the longitudinal midcallus areas from magnetized
and nonmagnetized limbs.
Clin Orthop 1987 Sep;(222):300-6.
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Effects of electromagnetic fields in experimental fracture repair.
Otter MW, McLeod KJ, Rubin CT.
Program in Biomedical Engineering, State University of New York at Stony Brook 11794-8181, USA.
The clinical benefits of electromagnetic fields have been claimed for
20 centuries, yet it still is not clear how they work or in what
circumstances they should be used. There is a large body of evidence
that steady direct current and time varying electric fields are
generated in living bone by metabolic activity and mechanical
deformation, respectively. Externally supplied direct currents have been
used to treat nonunions, appearing to trigger mitosis and recruitment
of osteogenic cells, possibly via electrochemical reactions at the
electrode-tissue interface. Time varying electromagnetic fields also
have been used to heal nonunions and to stabilize hip implants, fuse
spines, and treat osteonecrosis and osteoarthritis. Recent research into
the mechanism(s) of action of these time varying fields has
concentrated on small, extremely low frequency sinusoidal electric
fields. The osteogenic capacity of these fields does not appear to
involve changes in the transmembrane electric potential, but instead
requires coupling to the cell interior via transmembrane receptors or by
mechanical coupling to the membrane itself.
Clin Orthop. 1998 Oct;(355 Suppl):S90-104.
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Pulsed electromagnetic fields for the treatment of bone fractures.
Satter Syed A, Islam MS, Rabbani KS, Talukder MS.
Industrial Physics Division, BCSIR Laboratories, Dhaka.
The effectiveness of electrical stimulation and Pulsed Electro
Magnetic Field (PEMF) stimulation for enhancement of bone healing has
been reported by many workers. The mechanism of osteogenesis is not
clear, therefore, studies look for empirical evidence. The present study
involved a clinical trial using low amplitude PEMF on 19 patients with
non-union or delayed union of the long bones. The pulse system used was
similar in shape to Bassett's single pulse system where the electric
voltage pulse was 0.3 mSec wide repeating every 12 mSec making a
frequency of about 80 Hz. The peak magnetic fields were of the order of
0.01 to 0.1 m Tesla, hundred to thousand times smaller than that of
Bassett. Among the 13 who completed this treatment schedule the history
of non-union was an average of 41.3 weeks. Within an average treatment
period of 14 weeks, 11 of the 13 patients had successful bone healing.
The two unsuccessful cases had bone gaps greater than 1 cm following
removal of dead bone after infection. However, use of such a low field
negates Bassett's claim for a narrow window for shape and amplitude of
wave form, and justifies further experimental study and an attempt to
understand the underlying mechanism.
Bangladesh Med Res Counc Bull. 1999 Apr;25(1):6-10.
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Non-operative salvage of surgically-resistant pseudarthroses and
non-unions by pulsing electromagnetic fields. A preliminary report.
Bassett CA, Pilla AA, Pawluk RJ.
This report documents, for the first time, to the authors' knowledge,
the therapeutic use in humans of low energy, electromagnetic fields
pulsing in the extremely low frequency (E.L.F.) range. These fields,
established outside the body, were used to treat congenital and acquired
pseudarthroses and non-unions. Energy of this type appears to affect
biological processes, not through heat production, but through
electrically-induced changes in the environment of cells within the
organism. Of the 29 patients included in the study, 17 had experienced
at least one failure of surgical repair and, in each of these,
amputation had been recommended. The overall success rate, including
those patients treated with inadequate pulse characteristics and those
who failed to follow the protocol, was in excess of 70 per cent.
Improvements in the specificity of pulse characteristics hold promise
for increasing the rate of success. The simple, clinical methodology,
which is conducted on an out-patient basis, appears to be both safe and
effective. It can be applied with or without surgery. This approach
requires additional controlled investigations before it is ready for
general use in the orthopaedic community. The indications for amputation
of surgically-resistant pseudarthroses, however, should be reassessed.
The principles and technology, which have been established during this
endeavor, may have physiologic and practical significance for processes
other than pseudarthrosis and non-union.
Clin Orthop. 1977 May;(124):128-43.
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Acceleration of repair of non-unions by electromagnetic fields.
Sedel L, Christel P, Duriez J, Duriez R, Evrard J, Ficat C, Cauchoix J, Witvoet J.
This work deals with the results obtained by four French orthopaedic
departments using the electromagnetic field stimulation for non union
treatment. This is the method established by A. Bassett. 37 cases are
studied, the results are known for 35 of them with 6 failures and 29
successes. The failures can be explained for four of them by a bad
application of the device. Concerning the 29 successful cases, the role
of the stimulation is discussed. Discarding those who have been treated a
short time after a surgical procedure, those who have been immobilized
more than 6 months and those where the non union could have been a
delayed union, it remains 14 successful cases apparently undisputable.
For them the role of the electromagnetic field stimulation seems real.
Rev Chir Orthop Reparatrice Appar Mot. 1981;67(1):11-23.
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Treatment of ununited tibial diaphyseal fractures with pulsing electromagnetic fields.
Bassett CA, Mitchell SN, Gaston SR.
One hundred and twenty-five patients with one hundred and
twenty-seven ununited fractures of the tibial diaphysis were treated
exclusively with pulsing electromagnetic fields. The over-all success
rate in healing of the fracture with this surgically non-invasive
out-patient method was 87 per cent. The success rate was not materially
affected by the age or sex of the patient, the length of prior
disability, the number of previous failed operations, or the presence of
infection or metal fixation.
J Bone Joint Surg Am. 1981 Apr;63(4):511-23.
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Treatment of therapeutically resistant non-unions with bone grafts and pulsing electromagnetic fields.
Bassett CA, Mitchell SN, Schink MM.
This study reviews the cases of eighty-three adults with ununited
fractures who were treated concomitantly with bone-grafting and pulsed
electromagnetic fields. An average of 1.5 years had elapsed since
fracture and the use of this combined approach. Nearly one-third of the
patients had a history of infection, and an average of 2.4 prior
operations had failed to produce bone union. Thirty-eight patients who
were initially treated with grafts and pulsed electromagnetic fields for
ununited fractures with wide gaps, synovial pseudarthrosis, and
malalignment achieved a rate of successful healing of 87 per cent.
Forty-five patients who had initially been treated unsuccessfully with
pulsing electromagnetic fields alone had bone-grafting and were
re-treated with pulsing electromagnetic fields. Ninety-three per cent of
these fractures healed. The residual failure rate after two therapeutic
attempts, one of which was operative, was 1.5 per cent. The median time
to union for both groups of patients was four months.
J Bone Joint Surg Am. 1982 Oct;64(8):1214-20.
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The development and application of pulsed electromagnetic fields (PEMFs) for ununited fractures and arthrodeses.
Bassett CA.
This article deals with the rational and practical use of surgically
noninvasive pulsed electromagnetic fields (PEMFs) in treating ununited
fractures, failed arthrodeses, and congenital pseudarthroses (infantile
nonunions). The method is highly effective (more than 90 per cent
success) in adult patients when used in conjunction with good management
techniques that are founded on biomechanical principles. When union
fails to occur with PEMFs alone after approximately four months, their
proper use in conjunction with fresh bone grafts insures a maximum
failure rate of 1 to 1.5 per cent. Union occurs because the weak
electric currents induced in tissues by the time-varying fields effect
calcification of the fibrocartilage in the fracture gap, thereby setting
the stage for the final phases of fracture healing by endochondral
ossification. The efficacy, safety, and simplicity of the method has
prompted its use by the majority of orthopedic surgeons in this country.
In patients with delayed union three to four months postfracture, PEMFs
appear to be more successful and healing, generally, is more rapid than
in patients managed by other conservative methods. For more challenging
problems such as actively infected nonunions, multiple surgical
failures, long-standing (for example, more than two years postfracture)
atrophic lesions, failed knee arthrodeses after removal of infected
prostheses, and congenital pseudarthroses, success can be expected in a
large majority of patients in whom PEMFs are used. Finally, as
laboratory studies have expanded knowledge of the mechanisms of PEMF
action, it is clear that different pulses affect different biologic
processes in different ways. Selection of the proper pulse for a given
pathologic entity has begun to be governed by rational processes
similar, in certain respects, to those applied to pharmacologic agents.
Orthop Clin North Am. 1984 Jan;15(1):61-87.
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Results of pulsed electromagnetic fields (PEMFs) in ununited fractures after external skeletal fixation.
Marcer M, Musatti G, Bassett CA.
Of 147 patients with fractures of the tibia, femur and humerus, in
whom an average of 3.3 operations had failed to produce union, all were
treated with external skeletal fixation in situ and pulsed
electromagnetic fields (PEMFs). Of the 147, 107 patients united for an
overall success rate of 73%. Union of the femur occurred in 81% and the
tibia in 75%. Only five of 13 humeri united. Failure to achieve union
with PEMFs was most closely associated with very wide fracture gaps and
insecure skeletal fixation devices.
Clin Orthop. 1984 Nov;(190):260-5.
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Healing of nonunion of a fractured lateral condyle of the humerus by pulsing electromagnetic induction.
Das Sarkar S, Bassett CA.
Department of Orthopaedic Surgery, Sandwell District General Hospital, Lyndon, West Midlands, United Kingdom.
Nonoperative salvage of a surgically resistant case of established
nonunion of a fracture of the lateral condyle of the humerus in a child
is described. Solid union was achieved by treatment with pulsed
electromagnetic fields. A review of the literature indicates that this
is the first published report of such a case.
Contemp Orthop. 1991 Jan;22(1):47-51.
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Pseudoarthrosis
Pulsing electromagnetic field treatment in ununited fractures and failed arthrodeses.
Bassett CA, Mitchell SN, Gaston SR.
Pulsing electromagnetic fields (PEMFs) induce weak electric currents
in bone by external coils on casts or skin. This surgically noninvasive,
outpatient method, approved by the Food and Drug Administration in
November 1979, produced confirmed end results in 1,007 ununited
fractures and 71 failed arthrodeses, worldwide. Overall success at
Columbia-Presbyterian Medical Center was 81%; internationally, 79%; and
in other patients in the United States, 76%. Treatment with PEMFs was
effective in 75% of 332 patients (a subset) with an average 4.7-year
disability duration, an average of 3.4 previous operative failures to
produce union, and a 35% rate of infection. Eighty-four percent of
carpal naviculars and 82% of femoral neck-trochanteric nonunions were
united. After attempted arthrodeses could not salvage a failed
total-knee prosthesis, PEMFs promoted healing in 85% of patients. When
coils were unsuccessful alone, combining them with surgical repair was
effective.
JAMA. 1982 Feb 5;247(5):623-8.
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Congenital "pseudarthroses" of the tibia: treatment with pulsing electromagnetic fields.
Bassett CA, Caulo N, Kort J.
During the past seven years, 34 patients with infantile nonunions
associated with congenital "pseudarthroses" completed treatment with
pulsing electromagnetic fields (PEMFs). An analysis of results reveals
that 17/34 (50%) have achieved complete healing with biomechanically
sound union and radiographic demonstration of remedullarization. Union
with function, i.e., healing with continued need for protection, was
achieved in 7/34 (21%). Failure was the outcome in 10/34 patients (29%).
Most of these occurred in males with a history of early fracture (less
than 1 year) and with spindled, hypermobile lesions (Type III). During
the early period of the study, PEMFs were the sole means of treatment.
After a "coil effect" had been demonstrated, surgical realignment,
immobilization and grafting were combined with PEMF treatment.
Fundamentals of orthopedic management developed by the larger experience
with adult nonunions were found to apply equally to infantile nonunions
treated with PEMFs. These include effective immobilization of the
fracture site and controlled "stress working" during recovery to
facilitate gradual remodeling. PEMFs have been demonstrated to be a
potentially useful adjunct in the orthopedic surgeon's armamentarium for
treating infantile nonunions (congenital "pseudarthroses").
Clin Orthop. 1981 Jan-Feb;(154):136-48.
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Congenital pseudoarthrosis of the tibia: treatment with pulsing electromagnetic fields.
Kort JS, Schink MM, Mitchell SN, Bassett CA.
Ninety-two patients with congenital pseudoarthrosis (infantile
nonunion) were treated with pulsing electromagnetic fields (PEMF) in the
United States and Europe in the past eight years. This represents the
largest group of patients with infantile nonunions in which a common
treatment modality has been used. Excluding the ten lesions (11%) which
healed with refracture 48 lesions (59%) healed whereas 34 (41%) failed
to heal. The success rate in 23 type I and 34 Type II lesions was 77%
and 76%, respectively. Surgery in association with PEMF treatment did
not improve the results of treatment. The most important variable was
the radiographic morphology of the nonunion gap. Patients with spindled
bone ends, a large gap and a grossly mobile lesion had a very poor
prognosis relative to patients with a cystic or sclerotic transverse
fracture line with a gap of less than 5 mm. The key to success in the
treatment of infantile nonunions has been the combination of PEMF
treatment with good orthopedic management, consisting of rigid
immobilization, a nonweight-bearing status and rehabilitation with
impact loading exercise. Infantile nonunion remains a major challenge to
the orthopedic surgeon, but PEMFs appear to offer some important
advantages for overcoming this pernicious condition. Dr. Harold Boyd's
discussion of this paper follows. It was his final address to the AAOS.
Clin Orthop. 1982 May;(165):124-37.
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Pulsing electromagnetic fields to achieve arthrodesis of the knee
following failed total knee arthroplasty. A preliminary report.
Bigliani LU, Rosenwasser MP, Caulo N, Schink MM, Bassett CA.
Treatment with pulsing electromagnetic fields was used as an adjunct
in twenty patients who had had a knee arthrodesis after failure of a
total joint arthroplasty. Eighteen had had an infected arthroplasty;
one, mechanical loosening; and one, recurrent dislocation. Arthrodesis
had been attempted twenty-five times in these twenty patients prior to
application of the coils. These procedures included the use of
twenty-two external fixation frames, one compression plate, one
intramedullary rod, and one cylinder cast. Two groups of patients were
identified: those with non-union and those with delayed union. Fourteen
patients began treatment six months or more after arthrodesis and were
considered to have a non-union. The other six patients started treatment
less than six months after attempted arthrodesis because there was no
evidence of progression toward union. They were considered to have
delayed union. In seventeen (85 per cent) of the twenty patients a
clinically solid arthrodesis with roentgenographic evidence of
bone-bridging was achieved. The average time to union after coil therapy
was started was 5.8 months, with a range of three to twelve months. The
patients who started coil treatment earlier after arthrodesis showed a
tendency to heal faster. The three patients who had failures were the
only ones who did not adhere to the protocol, and all three were in the
non-union group. All patients with a solid arthrodesis were free of pain
and able to walk at the time of follow-up, nine to thirty-one months
after the completion of treatment. The use of pulsing electromagnetic
fields appears to be a valuable non-invasive adjunct when performing
arthrodesis of the knee after failed total joint arthroplasty.
J Bone Joint Surg Am. 1983 Apr;65(4):480-5.
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Long-term pulsed electromagnetic field (PEMF) results in congenital pseudarthrosis.
Bassett CA, Schink-Ascani M.
Bioelectric Research Center, Riverdale, New York 10463.
Ninety-one patients with congenital pseudarthrosis of the tibia have
been treated with pulsed electromagnetic fields (PEMFs) since 1973 and
all except 4 followed to puberty. Lesions were stratified by
roentgenographic appearance. Type I and type II had gaps less than 5 mm
in width. Type III were atrophic, spindled, and had gaps in excess of 5
mm. Overall success in type I and II lesions was 43 of 60 (72%). Of
those 28 patients seen before operative repair had been attempted, 7 of 8
type I lesions healed (88%), whereas 16 of 20 type II lesions healed
(80%) on PEMFs and immobilization alone. Only 19% (6 of 31) type III
lesions united, only one of which did not require surgery. Sixteen of 91
limbs (18%) were ultimately amputed, most before treatment principles
were fully defined in 1980. Fourteen of these 16 patients (88%) had type
III lesions. Refracture occurred in 22 patients, most as the result of
significant trauma, in the absence of external brace support. Twelve of
the 19 refractures, retreated with PEMFs and casts, healed on this
regime. Episodic use of PEMFs proved effective in controlling stress
fractures in several patients until they reached puberty. PEMFs, which
are associated with no known risk, appear to be an effective,
conservative adjunct in the management of this therapeutically
challenging, congenital lesions.
Calcif Tissue Int. 1991 Sep;49(3):216-20.
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The effect of postoperative electromagnetic pulsing on canine posterior spinal fusions.
Kahanovitz N, Arnoczky SP, Hulse D, Shires PK.
An experimental canine study was devised to evaluate the efficacy of a
noninvasive adjunct to improve the rate and quality of the posterior
fusion mass over the standard surgical technique. Ten large adult
mongrel dogs underwent a three-level lumbar spinal fusion. Bone excised
from the spinous processes was packed in removed facet joints and over
the decorticated laminae. To insure rigid internal fixation, custom-made
distraction instrumentation was placed bilaterally under the laminae of
the vertebrae above and below the three fused vertebrae. Five dogs
underwent electromagnetic pulsing, and five dogs acted as controls. Two
dogs were sacrificed at 4, 6, 9, 12, and 15 weeks to assess the
radiographic and histologic status of the fusion mass. Preoperative and
preautopsy hematologic studies as well as gross and histologic autopsy
specimens revealed no abnormalities attributable to the electromagnetic
pulsing. High-resolution radiography and histologic studies showed
earlier incorporation of the graft, improved new bone formation, and
better organization of the fusion mass in the 4-, 6-, and 9-week
stimulated specimens. However, by 12 and 15 weeks there did not appear
to be any histologic or radiographic differences between the stimulated
and control dogs. Although electromagnetic pulsing appears to produce an
early accelerated osteogenic response, it does not appear to improve
the overall results of primary canine spinal fusions.
Spine. 1984 Apr;9(3):273-9.
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Treatment of failed posterior lumbar interbody fusion (PLIF) of the spine with pulsing electromagnetic fields.
Simmons JW.
This paper presents a technique and discusses the results of treating
failed posterior lumbar interbody fusions (PLIFs) of the spine with
pulsing electromagnetic fields (PEMFs). Thirteen male patients suffering
from failed PLIFs, with an average time of 40 months since the last
surgical fusion attempt, were the subjects of this study. PEMFs were
applied by the patient according to strict criteria but in the comfort
of their home. Initial and subsequent medical evaluations closely
monitored the patient's condition and progress. PEMFs promoted a
significant increase in bone formation in 85% (11 of 13) of the patient
pool and achieved body-to-body fusion throughout the intervertebral disc
space in 77% (ten of 13) over the treatment period. The treatment
required no hospitalization, reduced morbidity, and avoided the risks
associated with surgical intervention. The results suggest that this
surgically noninvasive outpatient therapy may become a successful
alternative treatment of failed PLIF.
Clin Orthop. 1985 Mar;(193):127-32.
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Effects of pulsing electromagnetic fields (PEMF) on the course of vertebral fusion callus. A histological study.
Guizzardi S, Di Silvestre M, Govoni P, Strocchi R, Scandroglio R.
Istituto di Istologia ed Embriologia Generale, Universita degli Studi di Parma.
In this paper the findings concerning the effectiveness of PEMF on
the evolution of the vertebral fusion callus are reported. The study has
been carried on by preparing postero-lateral arthrodesis in the lumbar
spinal tract in rats. In this tract the laminae have been decorticated,
the articular processes prepared by decortication and removal of the
articular cartilage, and the spinal processes removed and employed as
osteoinductive material. The rats sacrificed after 4 and 8 weeks, show
how the decorticated areas are clearly influenced from PEMF, an early
appearance of the bony fusion callus is already evident in the treated
group just after 4 weeks. Also the articular areas are influenced from
PEMF but less markedly than the decorticated one; in these areas after 8
weeks the fusion callus is prevalently cartilaginous even if areas of
calcification are detectable inside. This different behaviour can be
explained with the absence of any form of spinal fusion by means of
surgical tools.
Acta Biomed Ateneo Parmense. 1990;61(5-6):227-35.
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A randomized double-blind prospective study of the efficacy of pulsed electromagnetic fields for interbody lumbar fusions.
Mooney V.
Division of Orthopaedic Surgery, University of California, Irvine.
A randomized double-blind prospective study of pulsed electromagnetic
fields for lumbar interbody fusions was performed on 195 subjects.
There were 98 subjects in the active group and 97 subjects in the
placebo group. A brace containing equipment to induce an electromagnetic
field was applied to patients undergoing interbody fusion in the active
group, and a sham brace was used in the control group. In the active
group there was a 92% success rate, while the control group had a 65%
success rate (P greater than 0.005). The effectiveness of bone graft
stimulation with the device is thus established.
Spine. 1990 Jul;15(7):708-12.
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Effects of smoking and maturation on long-term maintenance of lumbar spinal fusion success.
Mooney V, McDermott KL, Song J.
Department of Orthopaedics, University of California San Diego, USA.
This is a follow-up study of a multicenter, randomized,
placebo-controlled clinical trial conducted in accordance with the
condition for Food and Drug Administration approval for pulsed
electromagnetic fields. The purpose of this study was to evaluate the
long-term efficacy and safety of pulsed electromagnetic fields for
spinal fusion. An earlier clinical trial study was conducted to evaluate
the efficacy of Pulsed Electromagnetic Fields to enhance fusion success
at one year follow-up. In the original study, 195 patients undergoing
interbody fusion were enrolled. Of the 195 patients, 98 were in the
active group and 97 were in the placebo group. Study results showed a
92% successful fusion rate in the active group compared to 68% in the
placebo group. For this long-term follow-up study, all patients who had
healed in the original study were recalled for a follow-up radiograph.
Radiographs were assessed by the attending surgeon for fusion
assessment, when possible. The results of this long-term follow-up study
showed that there was a reduction in maintenance of the fusion over
time by 25%, but that the reduction was unrelated to treatment group and
correlated statistically with whether the patient was a smoker.
J Spinal Disord. 1999 Oct;12(5):380-5.
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Pulsing electromagnetic fields (PEMFs) in spinal fusion: preliminary clinical results.
Di Silvestre M, Savini R.
Istituto Ortopedico Rizzoli, Bologna.
Pulsing electromagnetic fields (PEMFs) were used during the
postoperative management of 31 patients submitted to lumbosacral
posterolateral fusion (PLF). The fusions were stimulated with PEMFs
during the first 2 of the 4 months of postoperative immobilization.
Consolidation of PLF was obtained in 20 of the 31 patients after 2
months of stimulation, thus, healing time was cut in half. After 4
months, fusion was observed in 30 out of the 31 cases submitted to
stimulation (96%).
Chir Organi Mov. 1992 Jul-Sep;77(3):289-94.
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Pulsed electromagnetic field stimulation on posterior spinal fusions: a histological study in rats.
Guizzardi S, Di Silvestre M, Govoni P, Scandroglio R.
Institute of Histology and Embryology, University of Parma, Italy.
This study reports the histological data relative to the effect of
pulsed electromagnetic fields (PEMFs) on the evolution of posterior
arthrodesis induced in the lumbar vertebrae of 12 adult male
Sprague-Dawley rats. After the operation, one group of six rats was
stimulated with PEMFs for 18 h per day, by means of a pair of coils
fixed to the outside of the cage. A control group of six rats was given
no stimulation after surgery. In the groups stimulated with PEMFs an
acceleration of the process of bone callus organization was already
observed after 4 weeks, and even more so after 8: An early replacement
was in fact observed of the newly formed cartilage tissue with primary
bone (at 4 weeks) and subsequently with secondary bone (after 8 weeks).
J Spinal Disord. 1994 Feb;7(1):36-40.
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The effect of pulsed electromagnetic fields on instrumented posterolateral spinal fusion and device-related stress shielding.
Ito M, Fay LA, Ito Y, Yuan MR, Edwards WT, Yuan HA.
Department of Orthopaedics, Hokkaido University School of Medicine, Sapporo, Japan.
STUDY DESIGN: This study was designed to examine stress-shielding
effects on the spine caused by rigid implants and to investigate the
effects of pulsed electromagnetic fields on the instrumented spine.
OBJECTIVES: To investigate the effects of pulsed electromagnetic
fields on posterolateral spinal fusion, and to determine if osteopenia
induced by rigid instrumentation can be diminished by pulsed
electromagnetic fields.
SUMMARY OF BACKGROUND DATA: Although device-related osteopenia on
vertebral bodies is of a great clinical importance, no method for
preventing bone mineral loss in vertebrae by stiff spinal implants has
been effective.
METHODS: Twenty-eight adult beagles underwent L5-L6 destabilization
followed by posterolateral spinal fusion. The study was divided into
four groups: 1) Group CNTL: without instrumentation, without pulsed
electromagnetic fields, 2) Group PEMF: without Steffee, with pulsed
electromagnetic fields, 3) Group INST: with Steffee, without pulsed
electromagnetic fields, 4) Group PEMF + INST: with Steffee, with pulsed
electromagnetic fields. At the end of 24 weeks, the dogs were killed,
and L4-L7 segments were tested biomechanically without instrumentation.
Radiographs and quantitative computed tomography assessed the condition
of the fusion mass.
RESULTS: Stress shielding was induced in the anterior vertebral
bodies of L6 with the Steffee plates; bone mineral density was increased
with the addition of pulsed electromagnetic fields, regardless of the
presence or absence of fixation. A decrease in flexion and bending
stiffness was observed in the Group INST; pulsed electromagnetic fields
did increase the flexion stiffness regardless of the presence or absence
of fixation, although this was not statistically significant.
CONCLUSIONS: Use of pulsed electromagnetic fields has the potential to minimize device-related vertebral-bone mineral loss.
Spine. 1997 Feb 15;22(4):382-8.
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Use of electromagnetic fields in a spinal fusion. A rabbit model.
Glazer PA, Heilmann MR, Lotz JC, Bradford DS.
Department of Orthopaedic Surgery, University of California, San Francisco, USA.
STUDY DESIGN: The biomechanical and histologic characteristics of
posterolateral spinal fusion in a rabbit model with and without the
application of a pulsed electromagnetic field were analyzed in a
prospective, randomized trial. In addition, fusion rate with and without
a pulsed electromagnetic field in this model was assessed by
biomechanical testing, radiographs, and manual palpation.
OBJECTIVES: To evaluate the influence of a pulsed electromagnetic
field on the spinal fusion rate and biomechanical characteristics in a
rabbit model.
SUMMARY OF BACKGROUND DATA: Previous studies performed to assess the
benefits of a pulsed electromagnetic field in spinal fusion have been
complicated by the use of instrumentation, and the animal models used do
not have a pseudarthrosis rate comparable to that seen in humans. In
contrast, the posterolateral intertransverse process fusion in the
rabbit is uncomplicated by the use of instrumentation and has been shown
to have a pseudarthrosis rate similar to that found in humans (5-35%).
METHODS: Ten New Zealand white rabbits each were randomly assigned to
undergo spinal fusion using either 1) autologous bone with
electromagnetic fields, or 2) autologous bone without electromagnetic
fields. A specially designed plastic constraint was used to focus the
pulsed electromagnetic field over the rabbits' lumbar spine 4 hours per
day. Animals were killed at 6 weeks for biomechanical and histologic
testing.
RESULTS: The rate of pseudarthrosis, as evaluated radiographically
and manually in a blinded fashion, decreased from 40% to 20% with the
pulsed electromagnetic field, but this decrease in the nonunion rate was
not statistically significant given the number of animals per group.
Biomechanical analysis of the fusion mass showed that a pulsed
electromagnetic field resulted in statistically significant increases in
stiffness (35%), area under the load-displacement curve (37%), and load
to failure of the fusion mass (42%). Qualitative histologic assessment
showed increased bone formation in those fusions exposed to a pulsed
electromagnetic field.
CONCLUSIONS: This study demonstrates the reproducibility of a rabbit
fusion model, and the ability of a pulsed electromagnetic field to
induce a statistically significant increase in stiffness, area under the
load-displacement curve, and load to failure of the fusion mass. This
investigation provides a basis for continued evaluation of biologic
enhancement of spinal arthrodesis with the use of a pulsed
electromagnetic field.
Spine. 1997 Oct 15;22(20):2351-6.
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Outcomes after posterolateral lumbar fusion with instrumentation in
patients treated with adjunctive pulsed electromagnetic field
stimulation.
Bose B.
Medical Center of Delaware, Newark, USA.
Fusion success and clinical outcome were determined in 48 high-risk
patients who underwent posterolateral lumbar fusions with internal
fixation and were treated with adjunctive pulsed electromagnetic field
(PEMF) stimulation postoperatively. An independent radiographic
assessment demonstrated a success rate of 97.9%. Following treatment,
59% of the working patients returned to their employment. Overall
clinical assessment was excellent in 4.2% of patients, good in 79.2%,
and fair in 16.7%; no patient had a poor clinical assessment.
Adv Ther. 2001 Jan-Feb;18(1):12-20.
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Electrical stimulation of spinal fusion: a scientific and clinical update
Kahanovitz N.
Hospital for Joint Diseases, 301 E. 17th Street, New York, NY 10003, USA. nkspinemd@aol.com
BACKGROUND CONTEXT: For over two decades, a number of electrical
stimulation devices have achieved increasing acceptance as adjuncts to
lumbar spinal fusion. Direct current electrical stimulation, pulsed
electromagnetic fields and more recently capacitive coupling have been
shown to have varying effectiveness when used to increase the success of
lumbar spinal fusion.
PURPOSE: The various electrical stimulation devices will be reviewed
with respect to the available basic science evidence validating their
use as spinal fusion adjuncts, as well as a review of the current
clinical data available to allow not only a discussion of their overall
clinical applicability, but more specifically their use in specific
spinal disorders and spinal fusion techniques.
METHODS: The existing peer-reviewed scientific literature will be
used to ascertain the scientific and clinical efficacy of electrical
stimulation to enhance lumbar spinal fusion.
CONCLUSION: Electrical stimulation devices have emerged as valid
adjuncts to attaining a solid lumbar spinal fusion. However, not all
stimulators are equally scientifically effective nor are they equally
effective clinically in achieving increased fusion success.
Spine J. 2002 Mar-Apr;2(2):145-50.
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Combined magnetic fields accelerate and increase spine fusion: a double-blind, randomized, placebo controlled study.
Linovitz RJ, Pathria M, Bernhardt M, Green D, Law MD, McGuire RA,
Montesano PX, Rechtine G, Salib RM, Ryaby JT, Faden JS, Ponder R, Muenz
LR, Magee FP, Garfin SA.
San Dieguito Orthopaedics, Encinitas, California 92024, USA. rjlmd@pacbell.net
STUDY DESIGN: The clinical study conducted was a prospective, randomized, double-blind, placebo-controlled trial.
OBJECTIVES: The purpose of this study was to evaluate the effect of
combined magnetic fields on the healing of primary noninstrumented
posterolateral lumbar spine fusion.
SUMMARY OF BACKGROUND DATA: Combined magnetic fields, a new type of
biophysical stimulus, have been shown to act by stimulating endogenous
production of growth factors that regulate the healing process. This is
the first placebo-controlled study to assess the effect of an
electromagnetic stimulus on primary noninstrumented posterolateral
lumbar spine fusion surgery as well as the first evaluation of combined
magnetic fields as an adjunctive stimulus to lumbar spine fusion.
METHODS: This multicenter investigational study was conducted at 10
clinical sites under an Investigational Device Exemption from the United
States Food and Drug Administration. Eligible patients had one-level or
two-level fusions (between L3 and S1) without instrumentation, either
with autograft alone or in combination with allograft. The combined
magnetic field device used a single posterior coil, centered over the
fusion site, with one 30-minute treatment per day for 9 months.
Randomization was stratified by site and number of levels fused.
Evaluation was performed 3, 6, and 9 months after surgery and 3 months
after the end of treatment. The primary endpoint was assessment of
fusion at 9 months, based on radiographic evaluation by a blinded panel
consisting of the treating physician, a musculoskeletal radiologist, and
a spine surgeon.
RESULTS: Of 243 enrolled patients, 201 were available for evaluation.
Among all patients with active devices, 64% healed at 9 months compared
with 43% of patients with placebo devices: a significant difference (P =
0.003 by Fisher's exact test). Stratification by gender showed fusion
in 67% of women with active devices, compared with 35% of those with
placebo devices (P = 0.001 by Fisher's exact test). By contrast, there
was not a statistically significant effect of the active device in this
male study population. In the overall population of 201 patients,
repeated measures analyses of fusion outcomes (by generalized estimating
equations) showed a main effect of treatment, favoring the active
treatment (P = 0.030). In a model with main effect and a time by
treatment interaction, the latter was significant (P = 0.024),
indicating acceleration of healing. Performed in the full sample of 243
patients, results of the intent-to-treat analysis were qualitatively the
same as in the evaluable sample of 201 patients.
DISCUSSION: This investigational study demonstrates that combined
magnetic field treatment of 30 min/d increases the probability of
successful spine fusion, and statistical analysis using the generalized
estimating equations model suggests an acceleration of the healing
process. This is the first randomized clinical trial of noninstrumented
primary posterolateral lumbar spine fusion, with evaluation by a
blinded, unbiased panel. This is the first double-blind study performed
to date assessing noninstrumented fusion outcome with extremely critical
radiographic criteria. The lower overall fusion rates in this study are
attributed to the high-risk patient group with an average age of 57
years, the use of noninstrumented technique with posterolateral fusion
only, and the reliance on extremely critical radiographic and clinical
criteria and blinded panel for fusion assessment without surgical
confirmation.
CONCLUSIONS: In conclusion, the adjunctive use of the combined
magnetic field device was statistically beneficial in the overall
patient population, as has been shown in previous studies of adjunctive
bone growth stimulation for spine fusion. For the first time,
stratification of fusion success data by gender demonstrated that the
female study population responded positively to the adjunctive combined
magnetic field treatment, with no statistically significant effect
observed in the male study population. Adjunctive use of the combined
magnetic field device significantly increased the 9-month success of
radiographic spinal fusion and showed an acceleration of the healing
process.
Spine. 2002 Jul 1;27(13):1383-9; discussion 1389.
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Osteonecrosis
Osteonecrosis of the femoral head treated by pulsed electromagnetic fields (PEMFs): a preliminary report.
Eftekhar NS, Schink-Ascani MM, Mitchell SN, Bassett CA.
This has been a preliminary report with a short-term follow-up of a
small number of observations (28 hips of 24 patients). The follow-ups
ranged from 6 to 36 months, with an average of 17.8 months. Only eleven
hips (in eleven patients) were followed an average of 8 months after
cessation of the treatment. It should be emphasized that this was a
"pilot" study, in which no control series was used to determine the
natural course of the disease in a comparable clinical setting. Of note
was the pain relief, in 19 of 23 patients with moderate to severe
pretreatment pain. Also there was an improved function, which suggests
that at least in approximately two thirds of the patients there was some
clinical benefit from this mode of treatment. In eight hips, clinical
conditions did not change; and in two they worsened, requiring further
treatment. Eighteen remaining hips were thought to have been benefited
by the treatment. Six femoral heads that had already developed varying
degrees of collapse (Ficat Type III) collapsed further (1 to 2 mm), and
two round heads (Ficat II) progressed to off-round (Ficat III). This
preliminary study suggests that further exploration of pulsed
electromagnetic fields (PEMFs) is warranted in the treatment of
osteonecrosis of the femoral head.
Hip. 1983;:306-30.
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Effects of pulsed electromagnetic fields on Steinberg ratings of femoral head osteonecrosis.
Bassett CA, Schink-Ascani M, Lewis SM.
New York Orthopaedic Hospital, Columbia Presbyterian Medical Center, Riverdale, NY 10463.
Between 1979 and 1985, 95 patients with femoral head osteonecrosis
met the protocol for treatment of 118 hips with selected pulsed
electromagnetic fields (PEMFs). Etiologies included trauma (17), alcohol
(9), steroid use (46), sickle cell disease (2), and idiopathy (44). The
average age was 38 years, and the average follow-up period since the
onset of symptoms was 5.3 years. PEMF treatment had been instituted an
average of 4.1 years earlier. By the Steinberg quantitative staging
method of roentgenographic analysis, none of the 15 hips in Stages 0-III
showed progression, and grading improved in nine of 15. Eighteen of 79
hips (23%) with Stage IV lesions progressed and none improved. In the
Stage V category, one of 21 hips (5%) worsened and none improved. Three
Stage VI lesions were unchanged. The overall rate of quantified
progression for the 118 hips, 87% of which had collapse present when
entering the program, was 16%. This value represents a reversal of the
percentage of progression reported recently by other investigators using
conservative and selected surgical methods. PEMF patients also have
experienced long-term improvements in symptoms and signs, together with a
reduction in the need for early joint arthroplasty.
Clin Orthop. 1989 Sep;(246):172-85.
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Use of pulsed electromagnetic fields in Perthes disease: report of a pilot study.
Harrison MH, Bassett CA.
A pilot study of pulsed electromagnetic fields (PEMFs) in the
treatment of 10 older children with unilateral Perthes disease of the
hip is reported. Patients were allowed to walk using crutches, with the
affected hip splinted by the Birmingham containment orthosis during the
day. For 10 h during the night the affected hip was exposed to PEMFs
delivered via a pair of coils, mounted anterior and posterior to the hip
joint on a plastic abduction orthosis. Splintage time of this group was
compared with that of 72 patients selected at random from a historical
control group of 200 patients. The 72 patients and the 10 children were
assigned to early or late groups depending on the radiologic evolution
of the disease when treatment commenced. The group of 10 children showed
an overall reduction of time in all splintage of 32% in early cases (to
12.8 months) and 18% in late cases (to 13.5 months). No untoward
effects were detected during the 2 years that these children have been
under observation. In view of the apparent safety of PEMFs and their
effects in this limited population of older patients with advanced
Perthes disease, a double-blind study in younger patients with earlier
lesions seems to be justified.
J Pediatr Orthop. 1984 Sep;4(5):579-84.
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