Agence d ’ Évaluation des Technologies et des Modes d ... · PULSED SIGNAL THERAPY AND THE TREATMENT OF OSTEOARTHRITIS i Summary SUMMARY Pulsed signal therapy (PST) is a therapeutic

Agence

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This assessment is an official report produced and published by the Agence d’évaluation destechnologies et des modes d’intervention en santé (AÉTMIS). It is also available in PDFformat on the Agency’s Web site.

Information concerning this report or any other report produced by AÉTMIS can beobtained by contacting it at:

Agence d’évaluation des technologies etdes modes d’intervention en santé (AÉTMIS)2021, avenue Union, bureau 1040Montréal (Québec) H3A 2S9

Telephone: (514) 873-2563Fax: (514) 873-1369E-mail: [email protected] address: http://www.aetmis.gouv.qc.ca

How to cite this report:

Agence d’évaluation des technologies et des modes d’intervention en santé (AÉTMIS).Pul sed si gnal therapy and the treatment of osteoart hritis. Report prepared by Alicia Framarin.(AÉTMIS 01-02 RE). Montréal: AÉTMIS, 2001, xiii-33 p.

Legal DepositBibliothèque nationale du Québec, 2001National Library of Canada, 2001ISBN 2-550-38441-5

© Gouvernement du Québec, 2001

This report may be reproduced, in whole or in part, provided the source is cited.

MISSION

To assist the Minister of Research, Science andTechnology and the policymakers in Québec’shealth-care system, including the Ministère dela Santé et des Services sociaux, by means ofhealth technology and intervention modalityassessments, specifically, by assessing theirefficacy, safety, costs and cost-effectiveness,and their ethical, social and economicimplications.

To assist the Minister of Research, Science andTechnology in developing and implementingscientific policy.

THE AGENCY’S MEMBERS

Renaldo N. Battista, M.D.President and Chief Executive Officer

Jeffrey BarkunPhysician (surgery)

Marie-Dominique BeaulieuPhysician (family medicine)

Suzanne ClaveauPhysician (microbiology/infectious diseases)

Roger JacobBiomedical engineer

Denise LeclercPharmacist

Louise MontreuilAdministrator

Jean-Marie MoutquinPhysician (ob stetr ics a nd gynec ology)

Réginald NadeauPhysician (cardiology)

Guy RocherSociologist

Lee SöderstromEconomist

SCIENTIFIC DIRECTOR

Jean-Marie R. Lance

PULSED SI GNAL THERAPY AND THETREATMENT OF OSTEOARTHRITIS

Osteoarthritis is a slowly and cyclically evolvingdisease with a high prevalence, especially among theelderly. Most often, it affects the joints in the hip,knee, cervical and lumbar spines, and fingers. Havinga noninvasive and nonpharmacologic treatment that iseffective in relieving pain and improving jointfunction is desirable.

Several studies have suggested using pulsedelectromagnetic fields as a therapeutic option, one ofthe applications being pulsed signal therapy (PST).Since the efficacy of these methods is still debated,the Collège des médecins du Québec asked theAgence d'évaluation des technologies et des modesd'intervention en santé (AÉTMIS) to assess PST inthe treatment of osteoarthritis. This assessment isessentially based on a critical review of the studiespublished on the subject.

The results of the studies examined strongly suggestan analgesic effect and improved joint function inosteoarthritis, but these results need to be confirmedby larger, methodologically well-designed studies andby a better understanding of the mechanisms of actionat work. The role of this therapy in relation to theother available treatments may then be better defined.

However, it is difficult to consider this technologypurely experimental, since it is already being used byphysiotherapy clinics, physicians in private practiceand private individuals in Québec and elsewhere inthe world. Consequently, AÉTMIS believes that theuse of pulsed signal therapy cannot be generalizedand that research should continue on its efficacy andcost-effectiveness in the treatment of osteoarthritis.

In disseminating this report, AÉTMIS wishes toprovide the best possible information to thepolicymakers concerned at different levels inQuébec's health-care system.

Renaldo N. BattistaPresident and Chief Executive Officer

PULSED SIGNAL THERAPY AND THE TREATMENT OF OSTEOARTHRITIS i

Summary

SUMMARY

Pulsed signal therapy (PST) is a therapeuticapplication of pulsed electromagnetic fields(PEMFs). This noninvasive technique consists inapplying an extremely-low-frequency (ELF)magnetic field, either with a ring or cylindersurrounding the affected part of the body, or withelectrodes applied on the skin. The most widelyknown application of pulsed fields is thetreatment of nonhealing fractures, i.e., those thatdo not heal after a few weeks of standardimmobilization with a cast. However, there areother possible applications. The purpose of thisreport, which stems from a request by theCollège des médecins du Québec, is to assess theefficacy of PST in relieving pain and improvingjoint function in osteoarthritis.

Osteoarthritis is a slowly and cyclically evolvingdisease with a high prevalence, especially amongthe elderly. It is characterized, among otherthings, by the gradual destruction of jointcartilage in pressure areas and by jointdeformities. The joints most often affected arethose in the hip (coxarthrosis), knee(gonarthrosis), cervical and lumbar spine, andfingers. Having a noninvasive andnonpharmacologic treatment that is effective inrelieving pain and improving joint function isdesirable.

A literature search revealed seven studies thathad investigated the efficacy of pulsed signaltherapy in the treatment of osteoarthritis, butonly four of them could be used for thisassessment. All of these studies havemethodological weaknesses. Furthermore, it is

difficult to compare the studies because theoutcome measures were different and the PSTtechniques differed in terms of electromagneticwave frequency, intensity and shape. Moreover,what the impact of these different parameterswas on the results obtained cannot bedetermined.

The results of the studies examined stronglysuggest an analgesic effect and improved jointfunction in osteoarthritis, but these results needto be confirmed by larger and methodologicallywell-designed studies and by a betterunderstanding of the mechanisms of action atwork. Consequently, AÉTMIS believes that thistechnology has almost reached the innovativestage, especially since it is already being used byphysiotherapy clinics, physicians in privatepractice and private individuals in Québec andelsewhere in the world and since the userprofessionals consulted believe that pulsedelectromagnetic field therapy may have a role toplay in the therapeutic arsenal for osteoarthritis.

However, pulsed signal therapy should not beput into general use until research in theappropriate settings has conclusivelydemonstrated its beneficial effects. Furthermore,it would be desirable if this research could, assoon as possible, compare this therapy with thealternatives from the standpoint of both efficacy(including the speed of onset of action andadverse effects) and cost-effectiveness. It wouldthen be possible to situate this therapy in relationto all the other therapeutic approaches toosteoarthritis.

PULSED SIGNAL THERAPY AND THE TREATMENT OF OSTEOARTHRITIS iii

Acknowledgments

ACKNOWLEDGMENTS

This report was prepared at the request of the Agence d’évaluation des technologies et des modesd’intervention en santé (as the Conseil d’évaluation des technologies de la santé du Québec wasrenamed on June 28, 2000) by Alicia Framarin, M.D., M.Sc. (health administration), a researchconsultant for the Agency. We sincerely thank her for her work.

Also, the Agency cordially thanks the external reviewers for their many comments, which helpedimprove the contents and quality of this report:

Dr. Jacques A. Duranceau P hysi at r ist, Cent re de m édeci ne or thopédi que et sport ive René-L aënnec, Mont -Royal , Québec

Dr. Bruno Fautr el Rheum at ologi st, Divi si on of Cli nical Epidem i ol ogy, McGi l lUni versi ty Heal th Cent re, Montr éal , Québec

Dr. P aul F or t in Rheum at ologi st, Dir ect or of Cli nical Resear ch, Ar thri ti s Cent er ofE xcel lence, Uni versi ty Heal th Networ k, and associ at e pr ofessor of m edicine, Uni versit y of Tor onto, T or ont o, Ontari o

L ouis E . T rem bl ay Associat e pr ofessor , S chool of Rehabi l it at ion S ci ence, Univer sit y of Ott awa, Ot tawa, Ont ar io

We also thank Hélène Saint-Amand, professional affairs coordinator, Ordre professionnel desphysiothérapeutes du Québec, both for her assistance in identifying an external reviewer withtraining in physiotherapy who is engaged in research or teaching, and for having providedcomments on the draft report.

Lastly, the Agency expresses its gratitude to Pierre Vincent, librarian, and Micheline Paquin,library technician, for their bibliographic support, and Maria-Edith Jacques, secretary, andSherinne Zencovich, graphic artist, for the final layout of this report.

PULSED SIGNAL THERAPY AND THE TREATMENT OF OSTEOARTHRITIS iv

Contents

CONTENTS

SUMMARY............................................................................................................................................................................. i

ACKNOWLEDGMENTS ................................................................................................................................................... iii

CONTENTS ........................................................................................................................................................................... v

LIST OF TABLES .............................................................................................................................................................. vii

LIST OF ABBREVIATIONS ............................................................................................................................................. ix

GLOSSARY .......................................................................................................................................................................... xi

1. INTRODUCTION ........................................................................................................................................................... 1

2. METHOD ......................................................................................................................................................................... 3

3. DESCRIPTION OF THE TECHNOLOGY ................................................................................................................ 5

3.1 TECHNICAL ASPECTS................................................................................................................................................. 53.2 MECHANISM OF ACTION ........................................................................................................................................... 63.3 COMPLICATIONS AND ADVERSE EFFECTS................................................................................................................. 63.4 STATUS OF THE CURRENT PRACTICE ........................................................................................................................ 7

4. THE USE OF PULSED ELECTROMAGNETIC FIELDS IN THE TREATMENT OFOSTEOARTHRITIS....................................................................................................................................................... 9

4.1 DESCRIPTION OF OSTEOARTHRITIS........................................................................................................................... 94.2 THERAPEUTIC APPROACHES ..................................................................................................................................... 94.3 DESCRIPTION AND ANALYSIS OF HARD DATA ........................................................................................................ 104.4 SYNOPSIS ON EFFICACY .......................................................................................................................................... 13

5. THE STATUS OF PULSED ELECTROMAGNETIC FIELD THERAPY......................................................... 15

6. CONCLUSION .............................................................................................................................................................. 17

APPENDIX A: FEATURES OF THE STUDIES EXCLUDED FROM ANDINCLUDED IN THE ASSESSMENT ................................................................................................ 19

APPENDIX B: ADDITIONAL INFORMATION ONTHE STUDY BY TROCK ET AL., 1994........................................................................................... 27

REFERENCES .................................................................................................................................................................... 31

PULSED SIGNAL THERAPY AND THE TREATMENT OF OSTEOARTHRITIS vii

List of tables

LIST OF TABLES

Table 1: Characteristics of pulsed electromagnetic fieldsand pulsed signal therapy .....................................................................................6

T able 2: Breakdown of the publi shed and unpubl ished studi es, i ncl uded in our revi ew, on the eff icacy of pul sed elect r om agnet ic f i el ds in t he tr eat ment of ost eoar t hr it i s accor di ng to t he st rengt h of the evi dence ............................................11

Table A.1: Features of the studies excluded from the review................................................21

Table A.2: Features of the studies included in the review.....................................................23

Table B.1: Results of the study by Trock et al, 1994: p value for the difference observedbetween the treated and placebo groups for each variable and for each timeperiod (significant if p ≤ 0.1). .............................................................................29

PULSED SIGNAL THERAPY AND THE TREATMENT OF OSTEOARTHRITIS ix

List of abbreviations

LIST OF ABBREVIATIONS

ELF Extremely low frequency

OA Osteoarthritis

PEMF Pulsed electromagnetic field

PST Pulsed signal therapy

RF Radiofrequency

VAS Visual analog scale

VLF Very low frequency

PULSED SIGNAL THERAPY AND THE TREATMENT OF OSTEOARTHRITIS xi

Glossary

GLOSSARY

Ampere (A): Unit of strength of an electric current.

Diathermia: A therapeutic method that uses high-frequency alternating electrical currentto heat (medical diathermy) or destroy (surgical diathermy) tissue.

Electric field: The effect of attraction or repulsion by a given charge on another unitelectric charge. It is due to voltage. The strength of an electric field is measured in voltsper meter (V/m) or in kilovolts per meter (kV/m) [WHO, 1998b].

Electromagnetic field: An electromagnetic field is associated with the presence of anelectric charge (electric field) and of electric current (magnetic field) [Novini, 1993].

Electromagnetic wave: Energy of natural or man-made source from oscillating electricand magnetic fields. It consists of very small packets of energy called photons. Theenergy in each photon is directly proportional to the frequency of the wave. Depending ontheir frequency and energy, electromagnetic waves can be classified as ionizing radiationor nonionizing radiation. Electromagnetic waves interact in different ways with biologicalsystems [WHO, 1998a].

Extremely-low-frequency (ELF) field: An electromagnetic field with a frequency lessthan or equal to 300 Hz. At such low frequencies, the wavelength in air is very long(6,000 km at 50 Hz and 5,000 km at 60 Hz) [WHO, November 1998]. The most commonsources of ELFs in the human environment are electricity and electrical equipment (50-60Hz) [Novini, 1993].

Frequency: The number of complete oscillations that pass a fixed point per unit of time.It is measured in cycles per second or hertz (Hz). One cycle per second equals 1 hertz.The higher the frequency, the more energy that can be emitted when an electromagneticfield comes in contact with a body. Very-high-frequency waves, i.e., those above 1015 Hz,constitute the ionizing radiation [gamma rays, x-rays, certain ultraviolet (UV) rays]produced by the sun, stars, radioactive bodies, x-ray tubes, UV lamps, etc. Waves oflower frequency are said to be nonionizing. They are visible light (1012 Hz), the infrared,microwaves, and television and radio waves [WHO, 1998a].

Gauss (G): A unit of measure of magnetic induction (magnetic flux density) (1 G = 0.1mT).

Hertz (Hz): A unit measure of the frequency of an electric field equal to one cycle persecond.

Ionizing radiation: Extremely-high-frequency electromagnetic waves (x-rays and gammarays) that have enough energy to produce ionization (create positively and negatively

PULSED SIGNAL THERAPY AND THE TREATMENT OF OSTEOARTHRITIS xii

Glossary

charged atoms or parts of molecules) by breaking the bonds that hold molecules in cellstogether [WHO, 1998a].

Lequesne algofunctional indices: Two indices developed by Lequesne for the purpose ofmeasuring three parameters: pain or discomfort, maximum walking distance and activitiesof daily living. These indices are used in diseases of the hip and knee. There are otherindices, such as the WOMAC (Western Ontario and McMaster Universities OsteoarthritisIndex). Little is known about the validity and reliability of these scales.

Magnetic field: The force exerted by a moving electric field (electromagnetism) or by apermanent magnet (static magnetic field). It is measured in amperes per meter (A/m) butis usually expressed in terms of the corresponding magnetic induction (magnetic fluxdensity), which is expressed in tesla (T), millitesla (mT) or microtesla (µT). In somecountries, magnetic induction is measured in gauss (G) (10,000 G = 1 T, or 1 G = 0.1 mT)[WHO, 1998b; Novini, 1993].

Nonionizing radiation: A general term for the part of the electromagnetic spectrum inwhich photon energy is too weak to break atomic bonds. Nonionizing radiation includesultraviolet radiation, visible light, infrared radiation, radiofrequencies, microwaves,extremely-low-frequency (ELF) fields and static electric and magnetic fields [WHO,1998a].

Radiofrequency: The frequency of an electromagnetic wave or an electrical signal lowerthan optical frequencies. The radiofrequency band is from 300 kHz to 300 MHz but caninclude microwaves and hyperfrequencies (up to 300 GHz), given their similarcharacteristics [Juutilainen, 1997].

Ritchie scale: The Ritchie scale (0 to 3) is used to assess joint pain in rheumatoidarthritis. Zero is the absence of pain or tenderness, and 1 is mild, 2 moderate and 3 severepain or tenderness.

Tesla (T): Unit of measure of magnetic induction (magnetic flux density) (1 T = 10,000G).

Very-low-frequency (VLF) field: An electromagnetic field with a frequency between 2kHz and 400 kHz [Novini, 1993]. The most common sources of VLFs in our environmentare televisions and video equipment.

Visual analog scale (VAS): A 10-cm-long, horizontal scale (nongraduated) on which thepatient indicates the intensity of his or her pain.

Volt (V): Practical unit of force of the current that feeds a circuit.

Watt (W): Unit of measure of electric power equal to the consumption of one joule persecond.

PULSED SIGNAL THERAPY AND THE TREATMENT OF OSTEOARTHRITIS xiii

Glossary

Wavelength: The distance travelled by a wave during one oscillation, or one cycle[WHO, 1998b]. It is determined by dividing the speed of propagation by the frequency.The higher the frequency, the shorter the wavelength [WHO, 1998a].

Wave generator: A device for producing electromagnetic fields. It is equipped with waveamplitude, frequency and modulation control devices.

PULSED SIGNAL THERAPY AND THE TREATMENT OF OSTEOARTHRITIS 1

Introduction

1. INTRODUCTION

Electromagnetism was discovered in the1800s by the English physicist MichaelFaraday [Ramey, 1998] and has, for a verylong time, been used in medicine fordiagnostic and therapeutic purposes. One ofthe therapeutic applications of magneticfields, pulsed electromagnetic field (PEMF)therapy, is used mainly in orthopedics totreat nonhealing fractures, but otherindications have been proposed, such asrelieving pain and improving joint functionin osteoarthritis. At least two types of pulsedmagnetic field generators have beenapproved by Health Canada.

The purpose of this Agence d'évaluation destechnologies et des modes d'intervention ensanté (AÉTMIS) report, which stems from arequest by the Collège des médecins duQuébec, is to assess the efficacy of one ofthe applications of pulsed electromagneticfields, called pulsed signal therapy (PST), inthe treatment of osteoarthritis and its use inQuébec and elsewhere. It examines theavailable scientific literature on the technicalaspects of electromagnetic fields and on theclinical applications of pulsed signal therapy.It also provides an overview of the currentsituation in Québec and elsewhere.


Method

2. METHOD

A search was conducted in Medline and theCochrane Database for the relevantpublished literature, using the followingkeywords: pulsed signal therapy, pulsedelectromagnetic fields, and electromagneticfields in combination with osteoarthritis. Wedid not impose any cut-off with regard to thedate of publication. We chose, for ourreview, studies published in English, French,German, Spanish and Italian, and thoseinvolving human subjects. The literature

search was complemented by hand-searching the bibliographies in the articlesconsulted. We also consulted the lists ofpublications from the International Networkof Agencies for Health TechnologyAssessment (INAHTA). Unpublishedstudies were identified by Web searches andby gleaning lists of references and articlesprovided by the manufactures. In severalcases, the authors were contacted.


Description of the technology

3. DESCRIPTION OF THE TECHNOLOGY

3.1 TECHNICAL ASPECTS

Therapeut ic devices based onelectromagnetic fields can be classified intothree main categories according to theirfrequency band: 1) radiofrequency (RF)generators (which usually operate at 27MHz); 2) low-frequency (VLF and ELF)electromagnetic field generators (1 Hz to 10kHz); and 3) sources of static magneticfields [Barker, 1993].

Radiofrequency generators are used inphysiotherapy to treat soft-tissue lesions.The technique is known as shortwavediathermy. The devices generate up to 100watts of electrical power and produce athermal effect responsible for physiologicalresponses such as increased blood flow andincreased tissue oxygenation. RF fields withfrequencies greater than about 1 MHz causeheating because of the movement of ions andwater molecules in the medium in whichthey flow. At frequencies below 1 MHz, RFfields induce electrical charges and currentsthat can stimulate cells in certain tissues,such as nerves and muscles [Barker 1993].

There are many sources of static magneticfields. They include bracelets, collars,insoles and other devices that one can applyon the skin. There is a wide variety ofclinical applications, but their efficacy hasnot been demonstrated [Aymerich et al.,1996].

Generators of extremely-low-frequency(ELF) fields produce pulsed electromagneticfields (PEMFs), which are said to have anonthermal beneficial effect. These arenoninvasive techniques in which the

magnetic field is applied from a ring or acylinder surrounding the affected part of thebody or by means of skin surface electrodes.The most widely known application ofpulsed fields is the treatment of nonhealingfractures, i.e., those that do not heal after afew weeks of standard immobilization with acast. There are other potential applications.For each one, the characteristics of therecommended magnetic waves are differentboth with regard to frequency andwavelength.

PEMF therapy, which is used mainly to treatnonhealing fractures, and pulsed signaltherapy (PST) both use electromagneticfields, although some authors make adistinction between the two approaches onthe basis of technical characteristics. Themain differences are presented in Table 1[Trock et al., 1993; Cossu et al., 1999].

The U.S. Food and Drug Administration(FDA) has approved a certain number ofelectromagnetic field generators for thefollowing three applications: 1) thestimulation of osteogenesis in cases ofnonhealing fractures; 2) congenitalpseudoarthrosis; and 3) spinal fusion. Threeof these devices generate low-frequencypulsed electromagnetic fields. No device hasbeen approved by the FDA for acceleratingfracture healing or treating osteoarthritis[Polk, 1996]. However, there at least twodevices on the list of medical devicesapproved by Health Canada [Health Canada,2000]. The cost of the devices is estimated atabout $5,000 CDN [Health Canada, 1998].



3.2 MECHANISM OF ACTION

Exposure to static or pulsed magnetic fieldshas effects on cell and organ function. Theeffects of PEMFs depend on the intensity ofthe electric field produced in the tissues.Magnetic induction of 1 A/m2 or more cancause acute and potentially harmful effects.At lesser intensities, various effects occur,some reversible, some not. The effects occurat different frequencies, intensities anddurations of exposure [Czerski et al., 1986].PEMFs produce three types of effects: ananalgesic effect, a stimulating effect onchondrocytes and a stimulating effect onosteocytes.

The analgesic effect attributed to PEMFs isapparently due to a change in the electricalpotential across the cell membrane, whichhas the effect of altering the release ofchemical transmitters in the synaptic spaceand thus causing a change in the reaction topain. When joint cartilage is subjected to thestress of physical activity, the electricalpotential created promotes chondrocytereplication and joint cartilage regeneration.A pulsed magnetic field apparently acts on

joint cartilage by generating an electricalpotential similar to that produced during thenormal functioning of a joint.

3.3 COMPLICATIONS AND ADVERSE

EFFECTS

Although the debate over the safety ofmagnetic fields and their effects in terms ofthe development of cancer continues,exposure to low-intensity fields over shortperiods of time is probably safe. However,treatment with pulsed electromagnetic fieldsis contraindicated in patients with cancer,pregnant women and pacemaker wearers[Trock, 2000]. The long-term effects ontissues in the exposed area are notdocumented in the currently availableliterature.

3.4 STATUS OF THE CURRENT PRACTICE

Two pulsed magnetic field generators are onthe list of medical devices approved byHealth Canada. In Québec, it appears thatfour companies market magnetic fieldgenerators and that one of them is an Ontariofirm. Most of those generators have been

Table 1: Characteristics of pulsed electromagnetic fieldsand pulsed signal therapy

PEMFs PSTEngery source Alternating current Unidirectional currentField intensity 2 G 12.5 G (0.15 -1.5 mT)Frequency 44-77 Hz 1-30 HzPulsation Constant AlternatingWave type Sinusoidal QuasirectangularDuty cycle < 50 % > 50 %Pulse frequency Continuous ModulatedFrequency source Fixed 6 frequency sources

Source: Documentation provided by a manufacturer and Cossu et al., 1999.



purchased and are being used byphysiotherapy clinics, physicians in privatepractice and private individuals. To ourknowledge, the costs associated with PEMFtherapy are not specifically covered by thedifferent health insurance plans but may becovered indirectly when included inphysiotherapy.

In France, use of PEMF is restricted toprivate centres, and the treatment is notcovered by insurance, according to apersonal communication from Dr. Perrot,Rheumatologist Unit and Pain Centre,Hôpital Cochin (November 1999). PEMFtherapy is also used at private centres inGermany and Italy, but it was not possible todetermine the extent of such use.


The use of pulsed electromagnetic fields in the treatment of osteoartritis

4. THE USE OF PULSED ELECTROMAGNETIC FIELDS IN THETREATMENT OF OSTEOARTHRITIS

4.1 DESCRIPTION OF OSTEOARTHRITIS

Osteoarthritis is a disease characterized bythe gradual destruction of joint cartilage inpressure areas, subchondral bony sclerosis,joint deformities and the formation ofosteophytes. It is a frequent health problem,and its prevalence increases with age [Felsonet al., 2000]. The prevalence of osteoarthritisafter the age of 65 is estimated at 68% inwomen and 58% in men (all sites combined)[Altman, 1994]. The disease manifestsmainly as pain and a loss of joint function.The joints most often affected are those inthe hip (coxarthrosis), knee (gonarthrosis),cervical and lumbar spine, and fingers[Pinals, 1996; Jackson, 1998].

The etiology of osteoarthritis is not knownwith certainty. For a long time, it wasassociated with aging. However, agingcartilage has different biochemicalcharacteristics than osteoarthritic cartilage[Sack, 1995; Schwartz et al., 1999]. Thedisease is probably due to a set of factorsthat cause a loss of joint cartilage integrity[Bagge, 1995], including joint injury,heredity, female gender, estrogen deficiencyduring menopause, and obesity [Jackson,1998; Sack, 1995; Jordan et al., 2000].

4.2 THERAPEUTIC APPROACHES

Osteoarthritis is a slowly evolving disease,with successive flare-ups and with periods ofremission. The main objective of treatmentis to relieve pain and improve joint function.The conventional approaches include,

among others: 1) nonpharmacologicmeasures, such as an orthosis with support(cane), physiotherapy, occupational therapy,physical activity, weight loss and supportgroups; 2) pharmacologic measures(analgesics, nonsteroidal antiinflammatories,intra-articular injections); and 3) surgicaltreatments (osteotomy and arthroplasty).

New developments are giving hope forinterventions that might protect deficientosteoarthritic cartilage and that might evenpermit cartilage regeneration. Theadministration of glucosamine or chondroitinsulfate could have effects on cartilageregeneration [Hochberg et al., 2000].Although a recent meta-analysis of 15randomized, double-blind, comparative trialswith placebo control groups evaluating theefficacy of glucosamine and chondroitinsulfate in the treatment of osteoarthritisshowed a positive effect, the AmericanCollege of Rheumatology believes that it istoo early to make any specificrecommendations regarding the use of thesecompounds because of the studies'methodological bias [McAlindon et al.,2000; American College of Rheumatology,2000].

Pulsed signal therapy is part of conventionalphysiotherapy care in the treatment ofosteoarthritis. Recent reviews ofnonpharmacologic approaches to treatingosteoarthritis discuss the use ofelectromagnetic fields for pain relief. Theuse of pulsed electromagnetic fields (PEMFsor PST) for relieving gonarthrotic pain is


The use of pulsed electromagnetic fields in the treatment of osteoarthritis

considered relatively expensive, given theresults obtained [Perrot et al., 1996], and anapproach whose efficacy has not beendemonstrated [Schwartz 1999].

4.3 DESCRIPTION AND ANALYSIS OF

HARD DATA

We identified six published studies and oneunpublished study on the effects of pulsedelectric and magnetic fields in the treatmentof osteoarthritis. Five of them were double-blind, comparative trials with placebogroups. The other two involved longitudinalcohorts with no comparison group, althoughone of them also included a comparison witha placebo group. In the studies with placebogroups, the patients in those groups wereexposed to simulations similar to theexposure in the experimental group, usingthe same type of device but in the inactivemode, i.e., without the generation of amagnetic field. It should be noted that thegenerating of a magnetic field does notproduce any noise or sensations that can beperceived by the patient. Neither the patientnor the attending physician knew whetherthe device was in the active or inactive modeduring the treatment sessions. However, thedevice's active or inactive status duringapplication was known to the personresponsible for applying the treatment.

All the studies were methodologicallyflawed. In most of them, the samples weresmall, and there is no discussion of thecalculation of the sample size required toensure sufficient statistical power. Theoutcome variables were based on subjective

observations. In most of the comparativestudies, improvement in the clinicalvariables was calculated only in relation tobaseline in both groups, not by comparingthe experimental group with the placebogroup. In those studies that were notcomparative and randomized, the observedimprovement could have been the result ofthe cyclic course of the disease, which canexhibit periods of spontaneous remission.Lastly, most of the studies were financiallysupported by the companies thatmanufactured the devices being tested.

Three of the seven studies were excludedfrom our review. In two of them, a techniqueother than PST was used, one employingpulsed electrical stimulation via skin surfaceelectrodes [Zizic et al., 1995], the otherpulsed magnetic shortwaves [VanSteenbrugghe et al., 1988]. The third studyexcluded was a pilot study with arandomized, double-blind, comparativedesign [Trock et al., 1993]. It was excludedbecause of the small sample size (27patients, 15 in the experimental group and 12in the placebo group), the loss to follow-up,which was 26% (33% in the experimentalgroup and 17% in the placebo group) and theheterogeneity of the experimental andplacebo groups, as they included patientswith different affected joints (knee, hand andankle). The subjective evaluation of pain andthe difficulty performing the activities ofdaily living can vary according to theaffected joint. The features and the results ofthe three excluded studies are shown inTable A.1 in Appendix A.



Four studies (three published, oneunpublished) on the efficacy of PEMFs inthe treatment of osteoarthritis were includedin this review. Table 2 shows the evaluationof the available literature on the subjectaccording to the strength of the evidence andindicates the number of articles in eachcategory.

The three published studies included in theanalysis are a randomized, double-blind,comparative trial with a placebo group[Trock et al., 1994], a study with a doubledesign (longitudinal cohort comparison) [DalConte et al., 1986] and a descriptive,longitudinal cohort study with nocomparison group [Cossu et al., 1999]. Thelatter two studies involved a follow-up of 6and 12 months, respectively. Table A.2(Appendix A) shows the features of thesethree studies.

Trock et al. studied the effects of PST in 86patients with osteoarthritis of the knee (42 inthe experimental group and 44 in the placebogroup) and 81 patients with osteoarthritis of

the cervical spine (42 in the experimentalgroup and 39 in the placebo group). Thefollowing variables were measured: 1) pain(10-cm VAS); 2) the difficulty performingthe activities of daily living; 3) pain onmotion and tenderness (measured by thephysician using a modified Ritchie scale);and 4) a global assessment of improvementby the patient and by the physician. In thecase of cervical osteoarthritis, limitation offlexion-extension and rotation was measuredas well. Improvement was measured by thepercent change observed at the midpoint oftherapy, at the end of treatment and onemonth after the end of treatment in relationto baseline.

A significant improvement of between 29and 36% in the measured variables wasobserved at the end of treatment in thetreated patients with osteoarthritis of theknee. The improvement varied from 11 to19% in the placebo group patients. Onemonth after the end of treatment, the percentimprovement was between 21 and 31% inthe experimental group and between - 0.3

Tab le 2: Breakd own of th e p ub li shed and u np u bl ish ed stu d ies, in cl ud ed in ou r review, on th e eff icacy of pul sed elect rom agn et ic f i el ds in t he treat ment of

ost eoart hrit i s accordi ng to t he st ren gt h of th e evi dence

Strength ofevidence

Description of study Number ofstudies

Number of patients

High - Level 1 Meta-analysis of randomized,

comparative trials

0 -

Level 2 Randomized, double-blind,

comparative trial with a placebo group

2 167 [Trock et al, 1994]

40 [Menkès, 1998]

Level 3 Randomized, comparative trial 0 -

Level 4 Prospective, nonrandomized,

comparative trial

0 -

Level 5 Case-control study 0 -

Low - Level 6 Clinical series, descriptive studies 2 233 [Dal Conte, 1986]

34 [Cossu, 1999]



and 16% in the placebo group. In the case ofcervical osteoarthritis, the improvement wasbetween 30 and 35% at the end of treatmentand between 20 and 39% one month later inthe experimental group. In the placebogroup, the improvement varied from 17 to27% at the end of treatment and from 0 to18% one month later. Although theimprovement was greater in the treatedpatients (experimental group), there was alsosignificant improvement in the placebogroup for most of the variables, whether atthe end of treatment or one month latercompared to baseline [Trock et al., 1994].

The comparative results between the treatedand placebo groups showed significantimprovement in pain in the case ofosteoarthritis of the knee and cervical spineat the end of treatment and one month later.Table B.1 (Appendix B) shows thecomparative results between the two groupsfor each of the measured variables and forthe different periods of time.

The second study had a double design. Onepart of the study involved evaluatingchanges in a group of 233 patients withcervical (n = 144) or lumbar (n = 89)spondylosis treated with a PEMF device.The results with regard to joint pain and jointfunction were evaluated at the end oftreatment, and three months and six monthsafter the end of treatment and werecompared with baseline. The observedimprovement was significant (p < 0.005) forall the variables and between eachmeasurement and baseline. The second partof the study compared the results obtained in29 patients who underwent three weeks ofsham treatment (treatment session with thePEMF device but without the passage ofcurrent) with the results obtained in the same29 patients treated for three weeks withPEMF after a period of three months with notreatment. The patients were not selected

randomly, and the sample was small. Theimprovement observed in the treated patientswas significant (p < 0.005) at the end oftreatment and three months and six monthsafter the end of treatment compared to thepretreatment data, while no significantimprovement was observed in the placebogroup [Dal Conte et al., 1986].

A longitudinal cohort study with nocomparison group was conducted in Italy forthe purpose of assessing the effect of pulsedsignal therapy (PST) on 34 patients (8 menand 26 women) with osteoarthritis of theknee [Cossu et al., 1999]. The patientsunderwent a cycle of nine 1-hour sessionswith intervals of less than 48 hours betweenthe sessions. The outcome variables werepain, as measured on a VAS of 1 to 10, painpresent during functional tests (range of 0[absence of pain in all the tests] to 10[presence of pain during all the tests]) andfunctional difficulty (assessed by means of aquestionnaire). Measurements were made atthe start of treatment (time 0), at the end oftreatment (time 1), and two weeks (time 2)and one year after the end of treatment (time3). None of the patients had undergonephysiotherapy, and five had takennonsteroidal antiinflammatories sporadicallyfor fewer than two consecutive days duringthe year of follow-up. On average, the painindex decreased from 7.12 to 2.38 (on ascale of 10) from time 0 to time 3, thedifference between the measurements beingsignificant (p = 0.01). Pain on motiondecreased as well, from 7.15 (time 0) to 1.47(time 3). The fact that there was nocomparison group makes it difficult tointerpret the results, given that the diseaseevolves cyclically, with periods ofspontaneous remission. Other studies areunderway in Italy, but this one is the onlyone published thus far (according toinformation from Christine Rosichelli, PSTItalia Srl, May 19, 2000).



The analgesic efficacy of PEMFs in kneeosteoarthritis was examined in a randomized,double-blind, comparative study involving40 patients (21 in the experimental groupand 19 in the placebo group) conducted inFrance in 1998 [Menkès et al., 1998]. Thisstudy, whose results have not beenpublished, found some evidence indicatingthat PEMFs are effective in the treatment ofknee osteoarthritis. The significantdifferences between the two groups wereobserved on the VAS for pain on motion(measured on day 9 and three months afterthe end of treatment) and the Lequesneindices measured three months after the endof treatment [Menkès et al., 1998]. Theauthors state that the study was of anexploratory nature and that the results needto be confirmed by a study including a largernumber of patients (written personalcommunication from Dr. Perrot, November1999). A description of the study is providedin Table A.2 (Appendix A).

Other unpublished studies have been carriedout in Italy and Germany for the purpose ofevaluating the efficacy of pulsed signaltherapy in the treatment of osteoarthriticpain. The studies were uncontrolled andinvolved small numbers of patients. Also, amulticentre study for evaluating the effectsof pulsed signal therapy on kneeosteoarthritis has just ended in Germany, butthe results have not yet been published.Preliminary results show an improvement inpain (VAS) and joint function (Lequesnealgofunctional index) of 50% after sixmonths of follow-up (p < 0.0001), accordingto a personal communication with Dr. RainerBreul, May 16, 2000. This study has still not

been published. We do not have any more-detailed information at this time.

4.4 SYNOPSIS ON EFFICACY

The published studies are few in number andare methodologically flawed. The onlypublished randomized, double-blind studywith a placebo-group used in this assessment[Trock et al., 1994] showed a considerableeffect in the placebo group. Althoughosteoarthritis evolves cyclically, withperiods of spontaneous remission, thelongitudinal cohort studies showed animprovement in pain and joint function afterPEMF therapy. These beneficial effectspersisted for several months and even up toone year. It is difficult to compare thestudies because the outcome measures weredifferent, even for the same variable.Additionally, the studies used PSTtechniques that vary in terms ofelectromagnetic wave frequency, intensityand shape. What the impact of thesedifferent parameters might have been on theresults obtained cannot be determined.

If the main effect of PEMF therapy is painrelief, such treatment will have to be situatedin relation to the other forms of osteoarthritistreatment that can relieve pain, such asnonsteroidal antiinflammatories and intra-articular treatments (corticosteroid infil-tration, hyaluronic acid injections and jointdebridement and lavage). These therapies areless expensive and have a faster speed ofonset of action, although they may havesome untoward or adverse effects. However,such an analysis cannot be performed untilthe efficacy of PEMF therapy is conclusivelyconfirmed by rigorous studies.


The status of pulsed electromagnetic field therapy

5. THE STATUS OF PULSED ELECTROMAGNETIC FIELD THERAPY

The classification adopted by the Agenced'évaluation des technologies et des modesd'intervention en santé for designating thestatus of a given technology is as follows:

1 ) An experimental technology is onewhose efficacy has not yet beenestablished. Such a procedure shouldtherefore not be used by healthprofessionals or in health-care facilities,except in the context of researchprojects.

2) An innovative technology is one that hasmoved beyond the experimental stageand whose efficacy has been established.However, because of a lack ofexperience, certain indications for its useand various aspects of its application arenot yet clearly defined. In addition, dataon the technology's cost-effectivenessmay be lacking or even nonexistent. Togain further knowledge of thetechnology, it would be important tosystematically gather all the dataacquired from its use and tocommunicate them to the medicalcommunity in the form of a clinicalresearch report or systematic review oran appropriate register. To further theseobjectives and to prevent its prematurewidespread use, the technology shouldbe restricted to certain authorized centreswith the necessary resources andknowledge.

3) An accepted technology is one that iswell established and for which there islengthy utilization experience and aknowledge of, or failing that, universalacceptance of its efficacy and cost-effectiveness in all its applications.

Because of the small number of studiescurrently available on the results of the useof pulsed electromagnetic field therapy inthe treatment of osteoarthritis, no firmconclusions can be drawn as to its efficacy.Although the technology seems to beeffective for certain indications, for example,the treatment of nonhealing fractures, themechanisms of action that promoteosteogenesis in this specific case aredifferent from those that act on pain andjoint function in osteoarthritis. Thistechnology is already being used byphysiotherapists and physicians in Québec,and private medical clinics in Canada andelsewhere in the world offer this service. It istherefore difficult to consider thistechnology purely experimental. We are ofthe opinion that its use in osteoarthritisshould be considered between experimentaland innovative and that it should not begeneralized until high-quality studies havedemonstrated its efficacy and explained themechanisms of action at work in thetreatment of osteoarthritis.


Conclusion

6. CONCLUSION

Osteoarthritis is a disease with a highprevalence, especially among the elderly.Having a noninvasive and nonpharmacologictreatment that is effective in relieving painand improving joint function is desirable.Several studies have suggested using pulsedelectromagnetic fields as a therapeuticoption, one of the applications being pulsedsignal therapy, whose efficacy hadpreviously been demonstrated for otherindications, such as the treatment ofnonhealing fractures.

In light of its assessment, AÉTMIS believesthat pulsed signal therapy has almostachieved the status of innovative technology.Although no firm conclusions can be drawnfrom the available scientific data, the latterstrongly point to an analgesic effect andimproved joint function in osteoarthritis.Furthermore, this technology cannot beconsidered purely experimental, since it isalready being used by physiotherapy clinics,physicians in private practice and private

individuals in Québec and elsewhere in theworld and since the user professionalsconsulted believe that pulsed electroma-gnetic field therapy may have a role to playin the therapeutic arsenal for osteoarthritis.

However, the use of pulsed signal therapycannot be generalized until larger,methodologically well-designed studies haveconfirmed its efficacy and until itsmechanism of action is understood. Researchshould therefore continue in the appropriateareas.

Lastly, it would be advisable for research tobe conducted as soon as possible to comparepulsed electromagnetic field therapy with thealternatives, both in terms of efficacy(including the speed of onset of action anduntoward or adverse effects) and cost-effectiveness. It will then be possible tosituate this therapy among all the othertherapeutic approaches to osteoarthritis.


Appendix A: Features of the studies excluded from and included in the assessment

APPENDIX A:

FEATURES OF THE STUDIES EXCLUDED FROM AND

INCLUDED IN THE ASSESSMENT



Table A.1: Features of the studies excluded from the assessment

Van Steenbrugghe etal., 1988

Trock et al., 1993 Zizic et al., 1995

Reason forexclusion

Pulsed shortwave therapy Small sample size (n=27).

27% lost to follow-up onemonth after the end of treatment(33% in the experimental groupand 17% in the placebo group).

Heterogeneity of theexperimental and placebogroups, as they includedpatients with different affectedjoints (knee, hand, ankle).

Electrical stimulation with skinsurface electrodes.

Objective To assess the efficacy of pulsedelectromagnetic-fieldshortwaves in tendon orosteoarticular disease.

To evaluate PEMFs in thetreatment of osteoarthritis.

To evaluate the safety andefficacy of pulsed electricalstimulation in the treatment ofosteoarthritis of the knee.

Design Controlled and double-blind,with a placebo control group.

Randomized, double-blind,comparative trial with a placebocontrol group.

Randomized, double-blind,comparative trial with aplacebo control group.

Equipmentused

27-mHz shortwave oscillator,power of 1 kW, emission of400 µsec pulsed at a lowfrequency (26 Hz) for the first5 sessions, then gradually at ahigher frequency (200 Hz).

Extremely-low-frequencyPEMF generator (< 30 Hz), 10-20 G of magnetic energy onaverage at a coil current of up to2 A drawn from a power sourceof 120 V AC. Pulse phaseduration: 67 ms, including 15micropulses with a pauseduration of 0.1 s.

Electrical impulses generatedby a portable device producinga low-frequency (100 Hz), low-amplitude, monophasic signal,which was applied via skinsurface electrodes, one on theknee, the other on the thigh.

Treatment Ten 20-minute sessions at therate of two sessions per week.

Eighteen 30-min sessions at therate of 3 to 5 times a week forone month

6 to 10 hours a day for fourweeks

Studypopulation

141 patients: cervicalgia(n=58), lumbalgia (n=42),knee osteoarthritis (n=16),shoulder tendon pain (n=13),various tendon problems(n=12).

21 patients with osteoarthritis ofthe knee.

5 patients with osteoarthritis ofthe hands.

1 patient with posttraumaticosteoarthritis of the ankle.

78 patients with osteoarthritisof the knee.

Lost tofollow-up

3% 27% 9%



Table A.1 (Cont’d): Features of the studies excluded from the assessment

Van Steenbrugghe etal., 1988

Trock et al., 1993 Zizic et al., 1995

Inclusioncriteria

Not specified. a) > 18 years.b) Altman’s criteria for

osteoarthritis.c) Symptoms of at least one

year’s duration.d) Symptoms incompletely

relieved with nonsteroidalanti-inflammatory drugs(NSAIDs), other analgesicsand physical therapy.

a) > 20 years.b) Osteoarthritis diagnosed

and treated.c) Patient consent.

Exclusioncriteria

Not specified. a) Patient started a newtreatment, includingNSAIDs, during theprevious month.

b) Osteoarthritis of anisolated joint in the hand orosteoarthritis of the spine

c) Pacemaker or unstablemedical illness.

Presence of another disease:aseptic necrosis of the femoralcondyle, juxta-articular Paget’sdisease, chondrocalcinosis,hemochromatosis,inflammatory arthropathy, etc.

Results Significant improvement inpain and functional limitationin the cases of cervicalgia.

No significant difference inthe other cases.

23 to 61% improvement in theclinical variables in the treatedpatients.

2 to 18% improvement in theplacebo group.

Significant improvement:physician assessment (p =0.023); patient assessment ofpain (p = 0.04); functionalevaluation by patient(p = 0.045).

Decrease in duration ofmorning joint stiffness of 20minutes in the treated groupand 2 minutes in the placebogroup (p < 0.05).

No difference between thegroups in terms of walkingtime, flexion, extension, jointtenderness or swelling.



Table A.2: Features of the studies included in the assessment

Dal Conte et al., 1986 Trock et al., 1994 Menkès et al., 1998 Cossu et al., 1999

Objective To evaluate the efficacy ofPEMFs in reducing painand functional limitationdue to cervical and lumbarspondylosis.

To evaluate PEMFs in thetreatment of osteoarthritisof the knee and cervicalspine.

To compare the efficacyand tolerance of pulsedmagnetic fields (PSTtechnology) in painful kneeosteoarthritis.

To evaluate, in the longterm, the efficacy of PST inthe treatment ofosteoarthritis of the knee.

Design Descriptive andcomparative (small sample,comparison between thesame cohort of 29 patientswho received placebotreatment and PST therapythree months later).

6-month follow-up after theend of treatment.

Randomized, double-blind,comparative trial with aplacebo group.

Randomized, double-blind,comparative trial with aplacebo group.

Longitudinal cohort.

12-month follow-up afterthe end of treatment.

Equipmentused

A Ronefor.

Frequency: 50 Hz.

Sinusoidal wave.

Maximum intensity of 33 Gfor the cervical spine and58 G for the lumbar spine.

ELF magnetic fieldgenerator using a coilcurrent of < 2 A drawnfrom a power source of 120V AC.

Energy applied stepwise: 5Hz, 10-15 G (10 min); 10Hz, 15-25 G (10 min); 12Hz, 15-25 G (10 min).

Number of pulses/burstdetermined by thefrequency; max.: 20.

Intensity: < 2A, 120 V.

Frequency: 2 to 60 Hz.

Pulse duration: 1.0 second;pause: 0.1 second.

PST generator; intensity:12.5 G.

Extremely low frequency(ELF) of 1 to 30 Hz withamplitude and durationmodulation.

Quasirectangular wave[Cossu et al., 1998]

Treatment 30 min per day, 4 weeks(open trial) and 3 weeks(controlled trial).

Eighteen treatmentsessions, each 30 minuteslong, 3 to 5 times a weekfor one month.

Nine 1-hour sessions during9 consecutive days.

Nine 1-hour sessions, withone session a day and abreak of no more than 48hours.

Studypopulation

144 patients with cervicalspondylosis.

89 patients with lumbarspondylosis.

86 patients withosteoarthritis of the knee(EG, n = 42 ; PG, n = 44).

81 patients withosteoarthritis of the cervicalspine (EP, n = 42; PGn=39).

40 patients: 21 in the PSTgroup and 19 in the placebogroup.

34 patients withosteoarthritis of the knee.

.



Table A.2 (Cont’d): Features of the studies included in the assessment


Lost tofollow-up

3% at the evaluation done 6months after the end oftreatment.

Different according to thevariables; maximum: 19%(one month after the end oftreatment).

10% one month after the end oftreatment and 37% three monthsafter the end of treatment.

No subjects lost tofollow-up.

Inclusioncriteria

Radiologic diagnosis ofgrade III or IV spondylosisand the presence of cervicalor lumbar pain syndrome.

a) > 35 years.b) Altman’s criteria for

osteoarthritis.c) Symptoms of at least

one year’s duration.d) Symptoms persistent

despite conventionaltreatment.

e) If osteoarthritis of thecervical spine: x-rayshowed disk spacenarrowing.

a) > 50 years.b) Painful knee osteoarthritis

according to ACR criteriawith rating greater than 40mm at rest and on motionon a pain VAS.

Pain for at least threemonths that persisted,despite the usualtreatment, plus radiologiccriteria [Cossu et al.,1998].

Exclusioncriteria

a) Pacemaker wearer.b) Presence of severe liver

or kidney disease,cardiocirculatoryfailure, severeosteopenia, even in asingle vertebra.

a) Patient began a newtreatment, includingnonsteroidal anti-inflammatories, orchanged treatments inthe previous month.

b) Pregnancy.c) Patient with pacemaker

or unstable medicalillness.

a) Pacemaker.b) Pregnancy.c) Coexisting rheumatic

disease: gout, rheumatoidarthritis, psoriasicrheumatism, infectiousarthritis, algodystrophy.

d) Recent intra-articularinjection (less than onemonth).

e) Having taken nonsteroidalanti-inflammatories andanalgesics in the 7 daysprior to the study.

f) Initiation of a disease-modifying treatment forosteoarthritis in the monthprior to inclusion.

g) Treatment in the form ofphysiotherapy,kinesiotherapy oralternative medicine.

h) Surgery scheduled within 3months.

i) Painful homolateralosteoarthritis of the hip.

j) Other therapeutic trial inprogress.

a) No pain at the timeof recruitment, evenif there wereepisodes of pain inthe previous 3months.

b) Presence ofneoplastic disease.

c) Unstable disease(hepatic cirrhosis,decompensateddiabetes, etc).

d) Patient withpacemaker [Cossu etal., 1998].



Table A.2 (Cont’d): Features of the studies included in the assessment


Outcomevariables

• Spontaneous pain.

• Provoked pain.

• Joint function.

• If cervicalosteoarthritis: nocturnalacroparesthesia,brachialgia, dizziness,headache.

• If lumbar osteoarthritis:hip pain, nighttimecramps.

• Global assessment bypatient.

• Assessment byphysician.

• Pain (VAS).

• Difficulty performingactivities of dailyliving.

• Pain on passivemotion.

• Tenderness.

• Global assessment bypatient.

• Global assessment byphysician.

• Evolution of spontaneouspain (VAS) at rest andduring movement.

• Spontaneous pain assessedwith a verbal scale at restand on motion, by theLequesne algofunctionalindex and a quality-of-lifequestionnaire (SF-36).

• Pain at rest.

• Pain on motion.

• Evaluation by motorfunctionquestionnaire.

Results Improvement in pain andjoint function in relation tobaseline.

The improvement peaked inthe 3 months following thetherapy and persisted at leastuntil the follow-upexamination at 6 months.

A follow-up of one year maybe too long for assuming thatthe improvement isattributable to the treatment.

Osteoarthritis of the knee:significant improvement inthe treated patients compa-red to the placebo group forall the variables, except painon passive motion.

Cervical osteoarthritis:significant improvement inspontaneous pain and in painon passive motion in thetreated patients compared tothe placebo group.

No significant differencebetween the two groups forthe other variables.

The most sensitive criteria fordifferentiating between the twogroups were the VAS for painon motion (significant differenceat the end of treatment and 3months after the end oftreatment) and the Lequesneindices (significant difference 3months after the end oftreatment).

A significant difference wasobserved for general health andmental health (SF-36) 3 monthsafter the end of treatment.

Gradual decrease in painat rest (on average, 7.12at the start of treatmentand 2.38 one year afterthe end of treatment) andon motion (on average,7.15 at the start oftreatment and 1.47 oneyear after the end oftreatment).


Appendix B: Additional information on the study by Trock et al., 1994

APPENDIX B: ADDITIONAL INFORMATIONON THE STUDY BY TROCK ET AL., 1994


Appendix B: Additional information on the study by Trock et al., 1994

Table B.1: Results of the study by Trock et al., 1994: p value for the difference observedbetween the treated and placebo groups for each variable and for each timeperiod (significant if p ≤≤≤≤ 0.1).

PeriodVariable

Mid-treatment (p)

End oftreatment (p)

1 month after (p)

Osteoarthritis of the knee

Pain (mm) NS 0.04 0.08

Difficulty performing the activities of dailyliving

NS 0.04 NS

Pain on passive motion NS NS 0.07

Tenderness NS 0.05 0.03

Patient’s assessment of his/her improvement NS 0.02 NS

Physician’s global assessment - 0.04 0.1

Osteoarthritis of the cervical spine

Pain (mm) 0.1 0.004 0.1

Difficulty performing the activities of dailyliving

NS NS NS

Pain on passive motion NS 0.03 0.0004

Tenderness NS NS 0.02

Patient’s assessment of his/her improvement NS NS NS

Physician’s global assessment - NS NS

NS: Not significant- : Figure not available


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Documents

Agence d ’ Évaluation des Technologies et des Modes d ... · PULSED SIGNAL THERAPY AND THE TREATMENT OF OSTEOARTHRITIS i Summary SUMMARY Pulsed signal therapy (PST) is a therapeutic