Stimulation of Bone HeaUng with Interferential Therapy

Methods ofe/ectrical stimu/ationof bone arereviewed fora comparison with the use of· in­terferencecurrents and fora considerationotthe possibJemerits of various methods. A sum­mary is givenot results of treatment ofa8pa­tients with delayed or non-union and predis­position to non-union, and the technique usedwith Interferential Therapy is described in detail.Results are also given of a study of the effectsof stimulation on 11 patients with acute frac­tures of the tibial shaft, compared with 11closely matched patients with similar acutefractures who did not receive Interferential Ther­apy. The advantages of surgically non-invasivetechniques are emphasised and recommenda­tions are made for the use of interference cur­rents prophylactically in specific cases.

JEANNE-MARIE GANNE

Jeanne..Marle Ganne, M.C.S.P., Dip. T.P., F.A.C.P., re..cently retired as Senior Lecturer in Physiotherapy atthe South Australian Institute of Technology, Ade..laide. She is a Fellow of the AustraHanColiege ofPhysiotherapists and President of the Australian Col­lege of Physiotherapists.

Stimulation of the body's naturalphysiological healing processes withphysical methods of treatment is an oldtherapeutic principle. Changes in rateof healing are most readily apparentclinically and experimentally in super­ficial tissues where regeneration can beclosely observed (Wolcottet oJ 1969,Dyson and Pond 1973, Dyson andSuckling 1978, Nikolova 1987), andwhere the penetration of electrical, ra­diant ormechanicaI energy can have adirect effect on cellular activity andvascular changes.

Clinically,changes in greater depthare assumed when signs of deeper in­flammation are rapidly resolved withlasting relief following treatment,whether these changes are broughtabout through reflex mechanisms and/or by effective localisation of currentsor fields at the affected site. Obser­vations of bone repair in humans mustrely on clinical tests, radiologicalap­pearancesand bone scans which willindicate the state of the bone's circu­lation.

Where trauma or disease has resultedin death of some cells and an abnormalbiochemical environment of others·withinterference in local cellular activities,

it has been rational, in view of the bio­electrical nature of the body's meta­bolic .activities, to assume that smallelectrical convection currents inducedin the tissues could be a stimulus formore rapid resumption of normal cell­ular activities.

The explosion of revived interest inelectrotherapy in the last twenty yearshas stimulated research in biomedical,surgical and other scientific depart­ments. This has resulted in more speci­fic histochemical exploration of theef­fects of electrical currents on tissuerepair to explain some of the changeslabelled generally 'alterations in me­tabolism' (Bassett et of 1964, Beckerand Murray 1967, Burny, et of 1978,Nikolova 1979 and 1987).

Changes have been observed in theactivity of enzymes related to tissuerepair. Norton et of .(1977) reportedchanges in cyclic adenosine mono­phosphate in epiphyseal cartilage tis­sues following their electrical stimula­tion for fifteen minutes. NikolovaandDavidov (1978) also found increasedactivity of enzymes following interfer­ential therapy in controlled experi...

-ments carried out· on traumatised sciaticnerves in rats. They reported earlier

recovery of the-activity of acetylcho­linesterase and also sharp increases inthe activity of alkalinephosphatases inthe affected muscle tissue together withconsiderable increases ·in the density ofthe capillary network. It bas beenknown for many years that increasedalkaline phosphatase also accompaniesosteoblast activity (Botterell and King1935). This work and other experi­mentsbyNikolova have now· beentranslated into English and form partof a recently published text book(Ni­kolova 1987). Results of this author'sexperiments on treatment of inducedhepatitis with interferential therapywere published .in Physiotherapy (Ni­kolova etaf1984).

Experimental work concemedwiththe healing potential of electric currentshas been most prolific in the area ofstimulation of bone repair,where theproblem.of ununited fractures becomesa serious financial and social burden.Early work in 1953 by the Japanesesurgeon Yasuda showed the relation­ship between mechanical stress andgeneration of electrical potential inbone. This prompted the extensive· ex­perimentalwork ofrnedical·scientistsin the sixties and seventies. It has been

The Australian Journal of Physiotherapy. Vol. 341 No~ 1,1988 9

Bone Healing with Interferential Therapy

Anode onthe skin

Figure 2: Technique using surgical in­vasion and Direct Current

Figure 1: Brighton's semi-invasive tech­nique using Direct Current (Adaptedfrom Brighton et a/1977, p.108)

Use ofa60Kilohertz SymmetricalSine Wave and Two SurfaceElectrodes

Brighton etal (1985) have recentlypublished a preliminary report of elec-

Use of Electro-magnetic FieldsBassett and his colleagues appreci­

ated some of the disadvantages of·sur­gical implantation of electrodes (Bas­settetal 1974, 1977),since:• most fractures heal without the need

for open reduction and thereforeap­plying a surgical procedure unneces­sarily cannot be justified

• implanted electrodes require a sec..ond surgical procedure to removethem

• implanted electrodes are small andbone formation spatially limited un­less multiple electrodes are·used

• there are also additional risks in­cluding infection.Bassettetal (1974) therefore devel­

oped a surgically non-invasive tech­nique using pulsed electro-magneticfields. This involves little risk to thepatient and does not interfere with con­servative management. The unit pro­ducing the pulsed field is fixed to theplaster and can be connected toastandard plug at home. At least 10hours of daily use are required for atleast three months and no weight hear­ing is allowed through the limb duringthis period. There is a detailed reportof this technique and results of treat­ment of 127 cases of ununited tibialdiaphyseal fractures, some of the pa­tients having been disabled for morethan· two years and facing amputation(Bassett et al 1981). An 87 .percentsuccess rate was achieved, regardlessof age, length of disability, presenceof infection or previous operative fail­ures. The technique has also. been usedin congenital and acquired pseudar­throsis (Bassett etal 1977), combinedwith grafting (Bassettetal 1982), tostimulate arthrodesis of the knee (Big­liani eta11983) and for failed posteriorlumbar interbody fusion (Simmons1985). Bassett (1985) quotes a 90 percent success rate.

Connectionsto battery,embedded.4 cathodes.at

fracture site

CathodaJ~

~T±~)Battery in

Platinum anode soft tissuesin soft tissues

Very good results are reported forachievement of bony union. Brightonin 1980 reports 87 per cent success in131 cases of tibial non-unions. He con­eludes that because there is no signifi­cant difference· between such resultsand those obtained with conventionalbone graft surgery,electrical treatmentof non-unions promises to become apreferred method.

There is usually no comment in thesereports on the overall function oflimbsat completion of treatment and theability of the patient to resume work.This should be an important consid­eration. Prolonged immobilisation andnon weight bearing do not favourfunc­tional recovery of joints and musclesand if there is an alternative it shouldbe coIitemplated when deciding onmanagement.

Insulated lead

published in numerous reports, in par­ticular in 1974 in the Annals oj theNew .York Academy oj Sciences (Vol..ume 238), in Electric Stimulation ofBone Growth and Repair edited byBurnyet 01 1978 (resulting from thefirst European Symposium on ElectricStimulation of Bone Growth and Re­pair in Brussels in 1976), and in Clin­icalOrthopaedicsand Related Re­search (Volume 124, 1977). This led tonumerous clinical trials of various tech­niques and currents. Small electrodeswere surgically implanted inside bonemedullary cavities at fracture sites orinserted percutaneously into bone andconstant direct current or various formsof pulsed low frequencycurrentsap­plied by means of batteries. Labora­tory experiments continue up to thepresent time; old experiments repeatedand at times with conflicting results.

It is not the purpose of this articleto give a detailed account of this work,however some reference to preferredmethods of clinical use is necessary inrelation to the possible advantages ofan alternative method using interfer­ence currents with surface electrodes.

Use of Direct -CurrentAlthough there hadbeenexperimen­

tal evidence that unidirectional and al­ternating pulsed currents were as ef­fective or more effective than constantdirect current to increase bone ·volume(Levy 1974, Klapper and Stallard 1974),surgeons have favoured the use of cath­odal electrodes inserted percutaneouslyat fracture sites, with constant currentfor a period of at least 12 weeks andthe limb non weight bearing (Frieden­berg 1971, Brightonet al 1975, 1977,Brighton 1980, Connolly 1981, Torb­jom et 0/1984). Anodes are applied tothe ·skin near the fracture site (Figure1).

Paterson et oJ (1980) .have· used sur­gically implanted cathodes in the formofa helix in the centre of the fractureand a single platinum anode positionedin soft tissues at least5cms from thecathode for optimum results (Figure 2).

10 The Australian Journal of Physiotherapy. Vol. 34, No.1, 1988

Bone Healing with Interferential Therapy

trical stimulation of fractures with es­tablished non-union using a 60 kilo­hertz sine wave (60,000 cps). Thecurrent is applied to the skin throughtwo windows on opposite sides of theplaster at the level of the non-union.The power unit is small and strappedto the limb proximally and supplied bya 9 volts transistor-radio battery, re­placed each day by the patient. Twoleads conduct the current to two smallround electrodes ·3cm in diameter .andthe patient applies electrode gel dailyto the electrodes. Stimulation is can"tinuous and current on the skin ismeasured as between 7.1 and 10.5 mil­liampereswith an effective 5 volts·frompeak tope.ak. The involved extremityis immobilized in plaster throughoutthe stimulation period and until unionis ·achieved.

Twenty-two well established non­unions were treated with an average of22.5 weeks of treatment. Full weight­bearing was immediately allowed in 4of the lower limb cases. The other 9patients with lower limb .fraetures de­layed full weight-bearing for twelveweeks. This difference did not seem toaffect the results of union. Of the 22patients, 17 obtained satIsfactory unionand remained aSymptomatic when fol­lowed up except one patient who felland refractured the scaphoid.

The authors have used the term 'ca­pacitively coupled" electrical field todescribe a displacement current as wellasa conduction current through theskin. They conclude that the methodhas distinct advantages over othermethods, asa non...invasive techniqueallowing weight-bearing.

It is interesting to note that the au­thors had planned to set up a double­blind study with controls as the treat­mentwas non-invasive. However pa­tients did not agree· t.oa .50 per centchance of wearing an inactive unit forpossibly up to 24 weeks. The presentwriter appreciates this problem. An al..ternative is to treat acute fractures withprophylactic stimulation and matchthem with an acute group withoutstimulation. This may at least show

whether rate of union is hastened bystimulation.

Use of Interference CurrentsPrior to all this work, Nikolova in

Bulgaria had already used surface elec­trodes with interference currents fordelayed and non-union and other frac­ture complications since 1963,and pro...phylactically for recent fractures since1966. (Duration of non-union not de­tailed.) Results of comparing varioustypes of physical treatment of 250 pa­tients with retarded callus formationwere reported atthe IV Czeckoslovak,..ian Orthopaedic Congress in 1967. The150 patients treated with interferentialtherapy had daily treatment for 15 to20 minutes (in contrast to continuousstimulation with the methods describedabove), using a 100 cps beat frequency.The number of treatments required ·toproduce· union varied between 15 and50. All the fractures were healed. Fiftyof the patients also received anabolicmedication during the period of stimu­lation---80per cent of these had alsocomplete functional recovery and 20per cent only minor residual symptoms- (Nikolova 1969 and 1987). Therewas fun functional recovery in 73 percent of the patients who had stimula-

. tion only andminor-residual symptomsin 22 per cent. This work wasappar­endy unknown inmost of the westel."nmedical world.

In relation to the effect of shortbursts of stimulation intermittently,Yasuda had appliedelectricalstimu­lation to the muscles of fractured legbones secured with intramedullarynails, in rabbits. He used four differentfrequencies, 10, 60, 100 and 250 cpsdaily for 15 minutes only, on four sep­arateexperimentalgroups.The musclecontractions also imparted vibration tothe fractured bones. The most promi­nentcallus formation occurred in thegroup receiving 10 cps and callus de..creased as the frequency of stimuli in­creased.He found that this bone hada good resonant frequency. to 10 cps(Yasuda 19741. Larger human bones

would have a lower resonant frequencyof vibration.

The weight of experimental and clin­ical evidence has suggested that an im­portant factor common to all methodsof electrical stimulation of healing is areaction of cells in response to an elec­trical field rather than to specific polareffects. Various theories have also been .proposed relating to physico-chemicalmechanisms,with alteration ofPH val­ues locally (Wollastetal 1978).

The writer had introduced the use ofinterferential therapy in South Aus­tralia in 1970, mainly for painful con­ditions. The beneficial effects of thecurrents on inflammatory symptomswere noted clinically (Ganne 1976). Thewriter decided to investigate its valuein 1974 for the treatment of delayedand non-union, based on Nikolova'sreport. The nature of these currentshave been describedelsewbere (Ganne1976, De Domenico 1982, Treffene1983). There are several advantages tothe use of interference currents in bonehealing:• electrodes are applied on the surface

and the medium frequency currentsare very comfortably toleratedthrough the skin because of the lowimpedance to their penetration;

• the treatment is therefore surgicallynon-invasive but has deep penetra.­tion (it was .later demonstrated byLaabs that the interferential field ispresent within the bone at the frac­ture site, the highest intensity beingin the medullary cavity);

• .the whole fracture site and areas ofbone around it can be exposed tothe currents including the osteoge­netic periosteal cells and the soft tis­sues around the fracture, allowingalso treatment of any pain and swell...ing;

• there are no electrolytic effects;• the nature of the currents with a

range of low frequency beats pro­duces therapeutic muscle contrac­tions and this also stimulates bonerepair;

• apart from saving time, applicationof treatment for only short periods

The Australian Journal of Physiotherapy. Vol. 34, No.1, 1988 11

Bone Healing with Interferential Therapy

Figure 4: Measuring the level of thefracture on the Xray film

imal limit for the fracture is thenmarked on the.plaster in the same way.This will indicate the exact span of thefracture in length. Bony prominencessuch as the medial malleolus make use­fullandmarks when the.limb is in plas­terancl the treatment must be carriedout through windows (Figure 4). If thelimb is out of plaster,.·where internalfIXation only has been used and theplaster is bivalved, palpation for tend­erness and irregularity assists in deter­mining the fracture site, but the X-Rayshould still be examined and measure­ments taken.

Distancefromdistallevel·offracture tomedialmalleolus

Distance fromproximal levelof fracture tomedialmalleolus

Selection and Position of ElectrodesAs in the treatment of joints and

soft tissues the size of the electrodesshould be sufficient to allow the spreadof the interference currents to includeall the affected area of bone and thesoft tissues adjacent to the fracture. Inrecent fractures treated prophylacti­cally, there will be local oedema pres'"entand possible·bruising or a skin .lac­eration or even a deeper wound; thisis .also usefully included in the field.

Four separate electrodes should beused to provide an effective field exceptfor facial fractures and fractures of themetacarpal and phalangeal bones whereequal double four-point electrodes areused.

When the limb is in plaster, fourwindows will have to be cut with anelectric saw. It is often necessary and

Proximal levelof fracture--

Distal level -f--+-f--'t--I--..,

\. I{ 4000"'" HZ

Beat frequency of 20 cpsat and around the fracture site

Method of Stimulation with Inter..ferential Therapy (I.T.)

The aim of the technique is to directas far as possible the maximum inter­ference at the fracture site and aroundit (Figure 3).

Figure 3: Crossing two medium fre­quencies using surface electrodes toproduce 20 cycles at fracture site

Determination of the Exact Area to BeTreated

The position of the fracture site andits·, extent >and the state of union, ifany, must be carefully examined on theX Ray fIlm after reduction, in both thelateral andantero-posterior views. Dis­tancesare measured exactly on the filmand the measurements transferred tothe relevant body area.

For example, in a tibial shaft frac­ture a measurement is taken of theexact distance between the tip of themedial malleolus and the distal limitof the fracture on the X Ray fIlm; thisis then transferred to the patient's limband marked on the plaster. The prox-

of these bones healed in average orbelow average times, one with slightdelay and one with considerable delay(Ganne 1979, 1980).

The number of patients referred forthis treatment was unfortunately smallas clinical investigations were startedat this time with surgical implantationof electrodes in the same hospital.

Since 1979 there, have continued tobe some requests for this treatment inSouth Australia, depending on theviews of individual surgeons and theinitiative of physiotherapists.

Summary <of Results of StimulationUsing Interferential Therapy

Over a period of four years 39 pa­tients ·were referred to the writer forstimulation of bone healing (one ofthese was bone grafted before comple­tion of treatment). Twenty-five of thepatients were referred for delayed ornon-union and 22 healed satisfactorilywithout further management and hadno residual loss of function (88010).These cases have been described else­where (Ganne 1980); however, of the9 diaphyseal. fractures of the tibia andfibula 7 were healed with an averagelength of treatment of 7.9 weeks, theshortest period of stimulation being 4weeks and the longest 13 Y2 weeks.These were severe fractures, five ofthem compound and four also com­minuted. The time interval from dateof injury or surgery to referral aver­aged 20 weeks, minimum period being11 weeks and maximum 33 weeks.Treatment was given three times a weekfor 30 minutes.

Thirteen acute cases (includingmainly mandibular fractures and.spinalfusions) were referred· with pain ·andswelling and predisposition to non...union, eg in the case of bilateral frac­tures of an atrophic mandible. Eleven

may be advantageous in avoiding tis­sue accommodation and constantslight irritation, but activating cellsat intervals;

• favourable effects have been foundclinically and reported experimen­tally on capillary circulation and in­hibition of sympathetic overactivity(Kaindl et aJ 1953, Nikolova 1968and 1987, Schoeler 1972, Ganne1980). The significance of adequateblood supply and venous return atfracture sites for repair is well docu­mented (Macnab and de Haas 1974,Rhinelander 1974, Trueta 1963 and1974, Whiteside and Lesker 1978).The effects on bone blood flow ofreleasing sympathetic tone wasshown by Shim and Patterson in1966.

12 The Australian Journal of Physiotherapy. Vol. 34, No.1, 1988

Bone Healing with Interferential Therapy

Postero..lateral windows cut

Electrodes in position

leads ··Il1erely being connected at .a dif­ferentangle (Figure 6). When the areais not in plaster, it is obviously possibleto vary the position of the electrodeseg on a fractured humerus, at timesanteroposterioriy· and then medio-lat­erally t depending on tbeangle of thearea still ununited. In the case of aforearm fracture it may be necessaryto direct the treatment to one or otherbone (Figures 7a,b t c). Limbs out ofplaster should be carefully supportedduring stimulation. If the position isaccurate the patientwillJeel· the·currentasa vibration around the fracture site.

Figure 5c:

Fibula

should not be too big, nor over thefracture as this may weaken the fIXa­tion and alter the reduction.

If using the .Nemectrodyntype elec­trodes it will be necessary to perma­nently angle the metal connection tothe electrode so that it can project ver­tically out of the window instead ofrequiring a larger opening. This is eas­ily done by a technical officer.and doesnot interfere with other treatments, the

Anterioretectrodeabove

Figure 5b: Right leg in plaster positionof windows to stimulate tibia

Figure 5a: Right leg cross sectionshowing electrode position

Anteriorwindowabove fracture

anteriorwindowbelow fracture

Position ofanterior border

advisable to repair or reinforce theplaster over the fracture site, and aboveand. below. it,and allow it to dry for24 hours before cutting the windows.The writer has often found that plas­ters are too thin or even cracked. Thewindows·should be very slightly biggerthan the electrodes, approximately~cm all round. For tibial shaft frac­tures electrodes 4 Y2cm by 6Ylcm aresuitable. The largest electrodes, ap­proximately 14cm. by 7Ylcm are nec­essary for the .femur and for spinalfusions. Around the knee where thecircumference of. the plaster is greaterand t~ebone end larger, in upper ex­tremity tibial fractures, electrodes 6cmsquare can be used without danger ofweakening the·plaster; this size can alsobe· used for humeral shaft fractureswhich are not in plaster.

The exact position of the electrodesis considered both longitudinally andin cross section. "Longitudinally theelectrodes should be at least 2cm prox­imal and distal to the span of the frac­ture. In cross section the position ofthe bone within the soft tissues mustbe considered. In the case of the tibialshaft, the bone is in a medial position,the medial surface being subcutaneous.It is important therefore to place theelectrodes ina correct line on eitherside of the bone medially, both ante­riorly and posteriorly and this must beaccurately estimated through the plas­ter (Figures 5aand 5b).The medialedges of the electrodes should justoverlap the anterior and medial bor­ders of the tibia. Comparison with theposition of the medial surface of thetibia on the unaffected leg is helpful.In practice this is achieved when . thelateral edge of the anterior electrodesis approximately in line with the 4thtoe. Electrodes .are held on the plasterin this estimated position and a linedrawn around them!hcmaway fromthe edge. Once cut, the windows arecarefully orientated and retained as theywill he immediately strapped back intoposition after treatment. If necessarythe plaster is reinforced at this point(Figure 5c). Note that the windows

The Australian Joumalol Physiotherapy. Vol. 34, No. 1, 1988 13

Bone Healing withlnterferentlal Therapy

M

Duration and Frequency of TreatmentTreatment has been given·· on five

days a week in acute cases or threetimes a· week in more chronic delayed

tures was also significantly effective forpain and swelling compared withcon~

troIs.Current intensity should be such as

to .produce a comfortable contractionof the muscles around the bone and adefinite awareness of vibration acrossthe fracture site. This sensation shouldbe carefully sought, controls being ad­justed.accordingly while questioning thepatient. He should feel the musclesgently but firmly 'holding the. fracture' .It may be necessary to build up to thisintensity in the first two treatments.More current is required to producethis effect when using larger electrodesover a bigger cross sectional area.

Occasionally shunting may occurlongitudinally along .an intramedullarynail, causing some discomfort fromconcentration at the extremities of thenail; in this case, the intensity can bekept just below this point of discom­fort.

Proximal

Figure 7c: Six weeks later

M

M

Proximal

Proximal

normalise tissue trophicity'. It shouldbe .appreciated that there is consider­able overlap in the effects of differentfrequencies on pain and swelUng. The20 .cycle .frequency used by the writerin experimental work on recent frac-

Figure 7a: Fractured L radius and ulnaununited at 13 weeks

Figure 7b: 10 weeks later after stimu­lation with IT, clinically united, POP off(treatment ceased)

Connection for___ n_ ._ I=I~I ~

A wettex pad is placed under the elec­trodeas usuaL The electrode is coveredwith a thick sorbo rubber pad the samesize as the window but slightly thickerthan the POP to ensure fIrm contactwhen tile electrode is strapped into thewind9w, with a suitable elastic webbingstrap. Note that if there is an openarea of skin, a sterile dressing wrungout in a sterile· normal saline solutionreplaces the wettex. (Where there aresigns and symptoms of Reflex Sym­pathetic Dystrophy the limb may ben­efit .appreciably from inhibition ofsympathetic tone ·by treating the rele..vant ganglion or nerve trunk areasproximally, using ·100 cycles).

Selection of Current and DosageThe dynamic field is preferable, us­

ing the vector modulation. In relationto frequency, Nikolova used 1()() cyclesfor delayed union (1969) and this fre­quency was used by the writer initially.Later the evidence of Yasuda's workon frequency quoted earlier in this ar­ticle suggested a change to a lower fre­quency could be more effective, and aconstant 20 cycles was selected. Thewriter experimented personally with thefeel of different frequencies on the jawand with the sensation of vibration inthe tibia at different frequencies. Toavoid sympathetic stimulation it maybe advisable to avoid sustained fre­quencies below 10 cycles but the fre­quency can also be set to vary between10 and 20 cycles per second. In recentfractures treated prophylactically Ni­kolova (1987) uses a frequency of 0 to100 initially 'because of its ability to

Figure 6: Nemectrodyn type electrodes

14 The Australian Journal of Physiotherapy. Vol. 34, No. 1, 1988

Bone Healing with Interferential Therapy

Table 1:Tibial experimental group

3. M. 39 V.A. (car)

2. F.63 Fall(rotation)

Uniontime inweeks

Management

Closed, p.a.p. 7.5 p.op.Remanip. wedged Hnail at 3 wks. P.O.P.

Closed, P.O.P. 12Remanip. achieved3/52 slight lat. shift&anteriorangulation.

Screw fixation and 12 p.op.P.O.P.

H nail, P.O.P. (same 11 p~op.

day)

Nature of injury

Transverse, mid. &lower 113 junction1000/0 displaced.

Oblique, mid-shaft,750/0 displacedLacerated ankles.

Spiral, lower shaft,2 em. displaced.

Oblique, mid-shaft,100% displacedslight wound.

Cause ofinjury

4. M. 17 V.A.(motorbike)

Sex andage

1. M.35 V.A.Alcoholic. (pedestrian)

Figure 8: Position of 4 point electrodesfor angle fracture of mandible

The tesults for the control and experimental groups are set out in Table1 and Table 2. An analysis of the difference between the matched pairsusing the t test was calculated (t= 3.01). This indicates that there was asignificant difference (p<O.01) between the two groups in rate of union.

Transverse, midshaft, Closed, P.O.P. 11slight displacement. (some lateral shift)

124 M. 21 Fell skiing Spiral, middle tolower shaft.

Closed, P.O.P. 8.5 p.op.unstable. Remanip.H nail 9 wks.

9 p.op.

8.5 p.op.

8.5

15.5

9.5 p.op.

Closed, P.O.P.

Closed, P.O.P.unstable. Screwfixaton, 9th day4

Closed, P.O.P.unstable. H nail9th day.

Compound, Closed, P.O.P.comminuted lower 1/3 Skin graft atdeep wound 3 em. 3 wks.

Oblique, mid-shaft75% displaced.

Transverse, mid. &lower V3 junction25% displaced.

Oblique, mid-shaftcompo comm. 75%displaced. Wound3 x 2 em. Infected.

Spiral, lower 1/3 tibia, Screw fixationupper V3 fibula & P.O.P.(identical to contra)).

9. M. 30 Sport(knockedover)

8. M.22 V.A.(motorbike)

7. M.26 V.A.(motorbike)

5. M. 17 V.A.(motorbike)

10 M. 19 Snapped bykick

11. M.29 Slipped onconcrete

union or where attendance more thanthree times a week is a problem. Thirtyminutes treatment has been given ateach attendance, but twenty minutesonly onsmaller bones such as the man­dible. (Figure 8) Where there is boneinfection a longer period of treatmentsis required; in contrast.a fractured me­tacarpal may require only a few treat­ments.Patients may be suddenly awareof the difference in sensation from oneday to the next when union occurs andslight crepitus disappears. Where thisis clear, the author has found fromexperience that t~eatment may thencease, but protection should continueuntil union is demonstrated radiologi­cally and this will be the surgeon's de­cision.

Experimental Trea'tment of ElevenAcute Fractures of the Tibia andFibula

Herbst (1987 p7) has pointed outthat 'quantitative evaluation of thehealing rate in humans when using dif­ferent stimuIationmethods is not pos..sible to-day because of the difficultyof .finding a sufficiently homogeneouspatient population.'

The Australian Journal of Physiotherapy. Vol. 34, No.1, 1988 15

Bone Healing with Interferential Therapy

10. M. 24 Snapped leg Transverse, mid-shaft Closed, P.O.P. 8against rail. 50% displaced.

N.B. Weight bearing policy the same in both groups.+ Integrity of P.O.P. was not always maintained in this case, though

H nail was stable.* Case No.6 could not be includedP.op = Post operation: P.O.P. = Plaster of Paris: V.A. = Vehicularaccident

Table 2:Tibial control group (previous co~secutive 18-month-period)

2. M.55 Fall(rotation)

The .problems. of comparative ·workmay be. magnified also by.more vari­abIes once there is•non-union, apartfrom ethical considerations. With largenumbers of patients, results of amethod ofeleetricalstimulation ofnon­union can. be compared with publishedresults of success with bone graft sur­gery,.;Aproblem with using .a con­trolled· trial is mentioned earlier.

Concerning the effect of IT on initialhealing rate the writer obtained infor­mation in a trial of IT on a group of11 acute fractures of the tibia ,andfi­bula in a period of 18 months. Thesecases were all under the care of thesame orthopaedic ·unit.·· Results werecompared with 11 cases treated withoutIT in the previous· consecutive 18month-period, on the same .unit. Theywere matched closely in relation to thecause of injury, the nature of the frac­tureand its management. There was astatistically significant.difference in theaverage rate of healing in the twogroups: 10.27 weeks in theexperimen­tal group and 17 weeks in the controlgroup (p < 0.01, using the t test)(Ganne 1980). Rate of healing wastherefore below normal average fig­ures, particularly for severe fractureswith .100 per cent displacement (Tablesl.and 2). An important additional find­ing was. the excellent and rapid func­tional recovery ·of the patients who hadIT stimulationandearlyretum to work(Table 3). These results have not ·pre­viously been published.

The current was appliedwben thefracture. was satisfactorily ·reduced andthe plaster quite dry. The writer be­lieves that stimulation should com­mence as soon as possible and in thefirst two weeks at least after reduction.The currents help to control oedemaand pain and facilitate the patient'sinitial ability to contract muscles stat­ically inside the plaster. TonnaandCronkite in 1961 observed the processof mitosis of periosteal cells followingfrC:lcture. They found that the initialproliferation starts 16 bours after in­jury. The reaction was observed alongthe entire diaphysis. Maximum in-

Uniontime inweeks

12 p.op.

12.5 p.op.

8.5 p.op.

18

Management

Closed, P.O.P. 30.5 p.op.Redisplaced - Hnail, 14th day.

Screw fixationP.O.P.

Closed, P.O.P. not 14perfect alignment

Screw fixation and 12 p.op.P.O.P.

Closed, P.O.P. 16 p.op.Redisplaced H nailat 2.5 wks.

Closed, P.O.P. 28.5 p.op.Remanip. infection.H nail at 2 wks.P.O.P.

Screw fixation,P.O.P.

Nature of injury

Spiral, junction mid.and low, shaft.

Oblique, mid·shaft,75% displaced.

Compound, Closed, P.D.P.comminuted, junction Skin graft.up &mid. V3.

Oblique, mid..shaft,25% displaced.

Transverse, mid-shaft, Closed, P.D.P. 27compound, Remanip. 10th day75% displaced. Slight lat. shift and

anterior angulation.

Spiral, lower shaft,1 em. displaced.

Oblique, mid..shaft,Compound,comminuted, 75%displaced.

Oblique, mid. & lowV3 junction, slightdisplacement.

Oblique, mid-shaft,compound, comm.50% displaced.

Spiral, lower V3 tibia, Screw fixation,upper Va fibula. P.O.P.Identical displ. toExperiment.

Cause ofinjury

4. M.21 V.A.(motorbike)

3. M.21 V.A.(motorbike)

7. M.57 V.A.(motorbike)

5. M. 19 Sport(ran intogoal post)

9. M. 33 Sport(knockedover)

8. M. 18 V.A.+ (motorbike)

Sex andage

1. M.55 V.A.Alcoholic (pedestrian)

12. M.33 Fell frombicycle

11. M.37 Slipped onconcrete

16 The Australian Journal of Physiotherapy. Vol. 34, No.1, 1988

Bone Healing with Interferential Therapy

Table 3: justify this. The treatment should beSummary of results of treatment of tibial fractures seriously considered for acute frac-

Case no. ClinicaJly firm Return to work Residual disabilitytures:• where healing is likely to be slow in

and (weeks post- patients with more general metabolicradiologically reduction) problems (alcoholic or osteoporoticprogressing conditions);

1 11 weeks Wandering Pensioner None at 24Proximal

2 12 weeks Normal home None at 17occupations at 14weeks

3 7.5 weeks Resume work 20 None at 12weeks

4 12 weeks Looking for work .at None at 2020 weeks

5 9.5 weeks Resume work 6.5 None at 13.5weeks

7 15.5 weeks Continued study Only 1/4 loss ofplantar flexionat 8 months

8 8.5 weeks 20 weeks - found a None, except3cm.job shortening at 16

9 11 weeks Resume work 3 None at 20weeks

10 8.5 weeks Continued work None at 14

11 8.5 weeks Resume work 10 None at 20 Figure 9a: Acute fracture, Case no 3,weeks re..displaced 3 weeks after injury

12 9 weeks Resume work 14 None at 12weeks

Proximal

Averagerate ofunion 10.27 weeks

crease was 32 hours after fracture.After 5 days, proliferation subsided tonormal except at the fracture site whereit was still above average two weekslater. These observations emphasise theearly activity of cells in the healingprocess and the immediate need foradequate blood supply and control ofswelling.

All patients were treated with 20 Hzfor 30 minutes, 5 days per week for atotal of 15 treatments. Once the 15treatments were completed the win-

dows were plastered back securely. Thepatients all took weight as soon as pos­sible and were discharged home be­tween the second and sixth week. ThefIrst assessment at six weeks was onlya radiological one: the first clinical as­sessment of union was as near as pos­sible to eight weeks (Figures 9a, b,c,dand 10a,b).

The results obtained even in thissmall group suggest that ideally stimu­lation could be used routinely wherepossible.. Time and equipment may not Figure 9b: Hodgkinson nail a week later

The Australian Journal of Physiotherapy. VoL 34, No.1, 1988 17

Bone Healing with Interferential Therapy

Proximal

Figure 9c: Case no 3 clinically unitedat 7..5 weeks post operation

Antero-posterior view

Proximal

Figure 9d: Case no 3Lateral view

e to reduce pain and swelling in recentfractures of the mandible which maynot require fixation, eg condylarfractures,

~ in bilateral leg fractures· where thereisa greater incidence of delayedunion with dilatation of vessels inone limb tending to cause simulta­neous vasoconstriction in the other(Wray 1963, Rosenthal et aI1977);

• bilateral mandibular fractures par­ticularly in edentulous patients wherethere is likelihood of delayed unjon(Rowe 1969);

.. for tibial shaft fractures that haverequired two or more manipulationsin 'the first two to three weeks toachieve an acceptable reduction;

• for fractures occurring in ·competi­tivesportsmen, particularly tibialshaft fractures and those involvingjoint surfaces;

• in upper limb fractures in musicianswhere perfect functional recovery isso ·important..Contra-indications to the use of this

treatment which may arise in patientswith fractures are similar ·to contra­indications in other cases. It is inad­visable to apply the current toa semi­conscious patient or one with a historyof very recent loss of consciousnessparticularly if the treatment lasts for

Proximal

Figure 10a: Acute fracture Case no 10,clinically united at 8.5 weeks

Antero-posterior view

more than 15 minutes, as the writerhas observed that this may cause in­creased drowsiness after IT, pointingto possible effects on the ReticularAc­tivating Centre. In the case of patho­logical fractures due to malignancythere are differences of opinion.. Ger...man authorities state that there is noevidence to suggest that this aggravatesthe condition (personal communica­tion).. The author has not applied .thecurrent through an area of the bodyknown to have malignancy.. The med­ical officer should make this .decisionif he believes it is worth a trial to relievepain..

DiscussionThe problem of establishing whether

a fracture considered to have delayedunion may heal of its own accord givenmore time,orbecome an establishedcase of non-union without some formof intervention is .well known. Nicollin his .survey of 705 cases of fracturedtibial shafts in 1964 stated that 'thedividing line between delayed union andnon-union must perforce remain im­precise in the majority of eases'; he

Proximal

Lateral view

18 The Australian Journal of Physiotherapy. Vol. 34, No.1, 1988

Bone Healing with Interferential Therapy

defined non-union as those cases inwhich the surgeon believed that furtherconservative treatment would not leadto union and recognised that this isoften a matter of individual judge­ment. Others have been more specific,defining delayed union in tibial shaftsas·a healing time longer than 20 weeks(Ellis 1958,Onnerfalt 1978), or 'noclinical or radiographic evidence ofumonat four to nine months .afterfracture' (Bassett.et al 1981). In suchan area of doubt,before resorting tosurgery it would seem preferable toinstitute a trial of electrical stimulationonly where progress in healing appearsstatic. The cost of hospitalization, ofsurgical appliances and operative pro­cedures and the demand for operatingtheatres would support such a policy.Surgical procedures such as .implanta­don of bone stimulators with invasivetechniques have been contemplated orcarried out in some cases after threemonths. Nine of the cases referred tothe writer were to have bone graftswhen ·IT was requested as an alterna­tive, and eight obtain:d union withouta graft.

The work of Bassett and Brightonand their colleagues have made it pos­sible to .salvage very long establishedcases of non-union; they refer to oneto three· year histories of non-union. Itis not possible to say whether IT couldproduce ·such results, without attempt­ing it. Where treatment is to be con­tinuous for many months it maybepreferable to organize home treatmentas in Bassett's method or that of Brigh­ton (1985).

There are obvious advantages inbeing able to treatsoft tissues includingmuscles and .also affect arterialcircu­lation and this is not possible with bonestimulation alone. Concerning smallareas of stimulation, .Brighton and hiscolleagues have described a new typeof cathode designed to improve thedistribution of the current in the med­ullarycanal and producing better boneformation experimentally (1981). Themodification was to be evaluated clin­ically.

It is an advantage to be able to pro­ceedwith partial to full weight bearingduring stimulation from a functionalpoint of view and this did not seem tointerfere with healing provided theplaster was intact. Brighton and Bas­sett .stressed the need for no weightbearing ·atall for 12 weeks with longstanding cases of non-union, usingsome techniques.

Chronic infection may cause delayin undertaking surgical procedureswhereas IT has been observed to hastendischarge and resolution.

Some cases of delayed union willrequire surgical measures, to achieve astable reduction or where soft tissue isinterposed between bone fragments.Some long standing cases have requireda combination of bone grafting withelectrical stimulation (Basett et a11982)

It was a matter for someconcemthat in nine of the patients referred tothe author the fractures had not alwaysbeen adequately held throughout theperiod when healing would be expectedto take place and delayed union mighthave been avoided. From the extensivenumbers of reported non-unions in theliterature it would seem that better pro­phylactic care is needed in the form ofcareful observation and attention tosimple details and patient instruction.

The method of stimulation describedby Brighton et al (1985) is of particularinterest as stimulation is appliedthrough surface electrodes and allowsweight bearing. The technique does ·re­quire complete co-operation of the pa­tient. The apparatus is light and port­able compared with the pulsedelectromagnetic device. In terms ofhours, the period of constant stimu­lation described in this preliminary re­port was very much .longer than thatused for IT stimulation, though thenon-unions were of longer standing. Ifa very long period of stimulation isrequired,home treatment is an advan­tage and can also be used more easilyfor country patients. There would beno stimulation of muscle contractionsand each patient also .requires a sepa­rate unit.

It is important to appreciate thatelectrical treatments can be successfulwhen currents are applied through theskin with appropriate knowledge andunderstanding,and ·that implantationof electrodes with surgical invasion isnot necessarily required.

ConclusionsThere are various advantages in the

different methods of electrical stimu­lation for bone healing. It is apparentthat a combination of physiological ef­fectsmay contribute to the healingprocess when using IT. The techniqueused by the author has been describedin detail to assist any member of theprofession who maybe in a positionto try a similar approach and to stimu­late further clinical research inspiteofthe problems.

Prophylactic stimulation of acutefractures with Interferential Therapyshould be considered more often, par­ticularlywhere there are factors whichpredispose to delayed or non-union. Itis a method of cboicealso, using tech­niques directed at the whole limb wherethere are signs ofSudeck'satrophy.

In fractures which are considered to 'have delayed union, a trial ofa non­invasive method of stimulation shouldbe preferredwhich.alIows weight bear­ing. If a decision is made to use inter­ferential stimulation this must· be givenan adequate trial and the ·techniqueaccurately applied.

Measures to prevent inadequateflX­ation of fractures should be more rig­orousand .include detailed instructionof the patient and careful observationby the staff concerned.

Appropriate electrotherapy can has­ten resolution of inflammation and re­pair of tissue and should continue tobe offered by physiotherapists. Clinicalexperience and concern for optimumresults at low cost to the communitywill hopefully reduce the need for re­peated complex surgical procedures.

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