R. A. de Bie,Physical therapist, doctoral studentHealth Sciences, University of Limburg.R. A. Steenbruggen,Physical therapist.Dr. L. M. Bouter,Lecturer in Epidemiology, University ofLimburg.

Translation: J. Klerkx M.Sc.,Maastricht.

NED. T. FYSIOTHERAPIE. VOL. 99 SPECIAL EDITION JANUARY 1989 PAG. 004 - 007

EFFECT OF LASER THERAPY ONANKLE SPRAINS

R. A. de Bie, R. A. Steenbruggen and L. M. Bouter

This paper presents the results of a randomised, double-blind intervention trial (N=38) on the effect of lasertherapy, applied as an additional treatment to a conventional therapy (Coumans taping) for ankle sprains. Effectswere compared between a laser group (N= 12), a placebo group (N= 11) and a control group (N=15). After fivedays pain scores in the laser group showed a significantly larger decrease than those in the other two groups, both byday and by night. After seventeen days the average decrease in pain scores was the same for alle groups. Impairmentof sports participation appears to be deminished slightly sooner, but this requires confirmation by further research.

Laser therapy has enjoyed increasing popu-larity over the past few years. Various pu-blications have shown spectacular effects ofthis therapy (1, 2, 3, 4, 8,12). Closer exami-nation of these effects shows that they canbe reduced to analgesia and biostimulationleading to accelerated recovery (13, 14, 16,17, 19, 20). The supposed physiologicalpoint of application for these two effects isvirtually identical (1, 4, 8, 19, 20). Lowenergy infrared photons accumulate in thecell, or in a molecule, until a sufficientenergy level is reached to allow a reactionto take place. This 'non-thermal catalysingeffect' is supposed to be unique to infraredand red laser light. In this way, stimulationof the cell's metabolism, and an acceleratedresumption of normal activities by the cellcould be specifically achieved (1, 5, 9, 11,19, 20). Histopathological studies (4, 9, 11,15, 19, 20) have shown that it is especiallyfibrocytes and macrophages which showincreased activity. Thus the tissues are (mo-re) rapidly cleared of pain transmitters,oedema is resorbed, and the tissues reco-ver. Vasodilatory agents are also said todisappear, reducing the inflammation (4).In addition, it has been reported that thestimulus threshold of axons may be raisedby the action of red and infrared laser light(4).

This general explanation provides argu-ments for the use of lasers in pain pointtreatments, with the aim of influencing themicroclimate near a pain point in such away that the stimulus threshold is raised (4,6, 18, 19). It has been suggested that theHelium-Neon laser, with its largely superfi-cial action is especially effective for certainskin disorders (1, 4, 5, 11, 18, 19), whileinfrared and red laser light is supposed tobe particularly effective for deeper structu-res (1, 3, 4, 6, 9, 10, 17, 18, 19). A study ofthe literature yields few clues for an ade-quate formulation of parameters for lasertherapy. It has been suggested to use dailytreatments with a low pulse frequency and a

short duration for acute lesions, and highpulse frequency, long duration treatment afew days apart for chronic disorders (1, 3, 4,6, 11, 18, 19). But usually it is impossible toderive a complete formulation of parame-ters from the available literature. Such aformulation is completely absent from thestudies by Poldi (13), Scardigno (1) andCanata et al. (3), while De Cuyper (4, 5)mentions only the number of treatmentsand the average duration of treatment percm2 as parameters. The type of laser used,which has consequences for the degree ofpenetration of the treatment, is often notindicated.

The reason for undertaking the presenteffect study on laser therapy was the lack ofvalid data on effects and effectiveness oflaser therapy. This lack is reflected espe-cially in the incomplete formulation of pa-rameters, the absence of sufficient informa-tion on the effect of laser therapy on acutesoft tissue injuries, and the attribution ofpossible effects to laser therapy on the basisof insufficiently valid arguments.

The aim of the study was to access theeffectiveness of laser therapy in treating asoft tissue injury by means of a randomized,double-blind intervention trial (26), thusgiving laser therapy a 'fair chance' to proveitself. For the soft tissue injury in this studywe chose ankle sprains. This t ype of injuryis often encountered in the physiothera-

pist's practice, and its treatment with laserlight can easily be standardized. Further-more, Poldi (13), Canata (3) and De Cuy-per (5) have reported favourable results oftreating ankle sprains, albeit on the basis ofvery little research. The use of laser therapyin the treatment of ankle sprains aims at areduction of the pain and swelling whichoccur in the acute phase, and in the long runat recovery of the affected ligaments. Thepresent paper limits itself to the assessmentof pain scores and impairment of sportsparticipation. Other items assessed in thestudy, such as restrictions in ADL func-tions, impairment of social contacts anddegree of satisfaction, have been reportedon elsewhere (24).

Patients and methods

During a continuous period of 15 weeks,patients with ankle sprains in a medium-sized general hospital were examined in theemergency unit by the physician in atten-dance. The standardized examination con-sisted of an anamnesis, visual inspection,manual examination, X-rays, and X-raystress test. These tests may lead to one ofthe following diagnoses (24, 36):

First or second degree ligament injury:these patients were enrolled in the study;

Third degree ligament injury: surgicaltreatment;

Ligament injury plus fracture: surgicaltreatment.Since operations on the ankle result in amore complicated situation, which is diffi-cult to standardize, these cases were notincluded in the study.The population of patients with first orsecond degree ligament injuries was subjec-ted to a further selection procedure. Onlythose patients were who presented injuriesto the ligamentum fibulare anterior and/orthe ligamentum calcaneofibulare laterale,which were not the result of congenitalweakness of the ligaments, and which wereless than 48 hours old. The subjects thus

4

Laser PlaceboPain:daytime 3.9 3.5

nighttime 3.9 3.5

Impairmentof sportsparticipation 9.0 9.8

A score of 10 corresponds to maximum complaintsA score of 0 corresponds to zero complaints

Control

3.74.1

9.7

After 5 days

After 17 days

Laser Placebo Control p-value Laser Placebo Control p-value71% 48% <0.05 90% 78% <0.0571% 53% <0.05 90% 91% n.s.

48% 53% n.s. 78% 91% n.s.n.s.= not significant

Table 2. Mean complaint scores before treatment

Table 3. Mean decrease (in %) in pain scores during the day

EFFECT OF LASER THERAPY ON ANKLE SPRAINS

selected were randomized into threegroups, all following the standard treat-

This treatment was as follows. The subjectshad their ankle taped up with a pressurehandage for three days, and were instruc-ted to keep the ankle in a high position andnot to walk on it. If after three days theswelling had decreased sufficiently to allowa dorsal flexion of at least 90 degrees, astandardized Coumans taping was applied(24). Two weeks later, the patient was gi-ven a new standardized Coumans taping. Ifafter two more weeks the physician andphysiotherapist found stability and perfor-mance of the ankle satisfactory on exami-nation, the treatment was stopped.

As mentioned earlier, the study populationconsisted of three groups. Group I was thelaser treatment group, group 2 the placebogroup, and group 3 the control group. Tofacilitate the laser treatment (30), a stan-dardized window was made in the taping(24) in groups 1 and 2. The laser treatmentwas given as an additional treatment, com-plementing the standard procedure. Allsubjects in groups 1 and 2 assumed theywere receiving laser therapy, since the lasergun, which had been fitted with a placebooption by the Enraf Nonius company, wasconstructed in such a way that neither thepatient nor the therapist could see whethera laser or placebo treatment was being ad-ministered (24). It should be noted that thelaser beam could be neither seen nor felt,and that it could only be established afterthe experiment which setting of the machi-ne actually corresponded to a working laserbeam. Groups 1 and 2 were treated with thelaser machine at a fixed time each morning.Treatment was given between 8.00 and 9.00each morning, including weekends, eachtime in the same room, at constant tempe-rature, humidity and lighting conditions.The treatment was always given by thesame therapists, with the patient always inthe same position.Standardization of the laser treatment in-plied the following. The pain point wasidentified and marked before starting thetreatment and/or opening the window inthe patient's Coumans taping. After localcleaning of the skin with alcohol, a switchon the laser gun was set in position 1 or 2.These positions corresponded to the twostudy groups. Subsequently, the laser pro-be was held vertically above the pain point,at a distance of 1 cm. next, the laser wasswitched on. It switched itself off after 180seconds, which meant the end of the treat-ment. After treatment, the foot was tapedup with a pressure bandage again, or, if theCoumans taping had already been applied,the window was taped up again accordingto standard procedure (24).

In all, ten laser treatments were administe-red, the first of which took place within 48hours after the ankle sprain. This represen-ted the first treatment in the series, which

continued with treatments on the 2nd, 3rd,4th, 5th, 7th, 9th, 11th, 14th, and 17th days(24). The soft laser used in the study wasthe endo-laser 465, equipped with an infra-red probe with a wavelength of 780 nm, anda placebo option. The parameters used we-re: a treatment time of 180 seconds, a pulseenergy of 5 mW and a pulse frequency of 80Hz. Pulse time was 0.3 msec, at a beamdiameter of 1 mm and a skin-probe distanceof 1 cm.From the moment of randomization, allthree groups, i.e. the laser, placebo andcontrol groups, were asked to fill in a scoreform, for the duration of the study, at afixed time each day (see Appendix 1). Inpractice, this meant that subjects filled in aform early in the morning (e.g. at break-fast), recording their experiences of theprevious day and night. Data were analysedusing statistical tests for small populations.The data presented in the present paperwere analysed by means of Student's t test.

Results

All persons who were enrolled for the studyand satisfied the requirements (N=38)cooperated. The description of the studypopulation in Table 1 shows that the groupsmay be regarded as comparable in sex, ageand compliance.

Table 2 shows the complaint scores for thethree study groups before the start of theexperiment. Since there were slight diffe-rences in scores between the study groups,

Table 1. Study population

effects of treatment are always expressed aspercentages of decrease in the scores withrespect to the original score for that group.After 5 days, the average decrease in painscores during the day was found to be largerfor the laser group than for both the place-bo group and the control group. Table 2also shows that there was no significantdifference in complaint scores between theplacebo group and the control group. Afterseventeen days, there was only a (slight)significant difference between the lasergroup and the placebo group.

Table 4 reveals that the average decrease(in %) in pain scores at night also reached apeak after five days. Again, the differencesbetween the groups had practically disap-peared after seventeen days.Since all responders were actively engagedin sports, impairment of sports participa-tion could be used as a measure of the effectof treatment. Average decreases (in %) inimpairment of sports participation after fi-ve and seventeen days are shown in Table5. After five days, there was a significantlylarger decrease in impairment of sports par-ticipation in the laser group as compared tothe placebo group, but the difference indecrease between the laser and controlgroups was far less obvious. After seven-teen days, the average decrease in impair-ment of sports participation was still foundto be largest in the laser therapy group, butthe placebo group also showed a relativelylarge decrease in complaint scores compa-red to the control group.

Laser Placebo ControlNumber 12 11 15Men 67% 64% 67%Mean age 26 27 26Compliance 100% 100% 100%

5

Complaint Scoring Form

Name:

Date of birth:

Occupation:

Sport/hobby:

Group:

Date:

Give a mark for each of the items, and indicate this on the scales.Mark 10 means maximum score; mark 1 means minimum or no score.

Pain: 10 means maximum pain; 1 means no pain

At night:1 2 3 4 5 6 7 8 9 10

Daytime:1 2 3 4 5 6 7 8 9 10

Daily activities: to what extent are you hampered in your daily activities by your injury?10 means maximum impairment0 means no impairment

Work:1 2 3 4 5 6 7 8 9 10

House-work:

1 2 3 4 5 6 7 8 9 10

Sports:1 2 3 4 5 6 7 8 9 10

To what extent does your injury affect your social contacts with relatives, friends andothers?

Social:1 2 3 4 5 6 7 8 9 10

Are you satisfied with the therapy?10 means utterly dissatisfied0 means completely satisfied

Satis-faction:

1 2 3 4 5 6 7 8 9 10

After 5 days After 17 days

Laser Placebo Control p-value Laser Placebo Control p-value

98% 76% <0.005 97% 95% n.s.98% 60% <0.005 97% 94% n.s.

76% 60% <0.025 95% 94% n.s.n.s.= not significant

After 5 days After 17 days

Laser Placebo Control p-value Laser Placebo Control p-value

8% 0% <0.05 42% 37% n.s.8% 4% n.s. 42% 18% <0.025

0% 4% n.s. 37% 18% n.s.n.s.= not significant

NED. T. FYSIOTHERAPIE. VOL. 99 SPECIAL EDITION JANUARY 1989

Appendix 1

Table 4. Mean decrease (in %) in pain scores during the night

Table 5. Mean decrease (in %) in impairment of sports participation

Discussion

The study population in the clinical trialreported here was small, hence there is thepossibility that a relevant effect of lasertherapy has not been revealed. However, alack of power does not necessarily meanthat the findings of a study are meaningless(25). The aim of the present study was toinvestigate whether laser therapy had anydemonstrable effects in complaints whichlend themselves relatively well to treat-ment. Hence a generalisation of the fin-dings to other complaints and/or patientswas of secondary importance in this case.

Complaint scores in this study were asses-sed by means of V.A.S. (Visual AnalogScale). These scales seemed most appropri-ate for our purposes. This is, of course,debatable. However, studies by Revill etal. (33) have shown that on the basis ofthese scales, subjects can provide very pre-cise information on the pain they have ex-perienced over the past 24 hours. Severalother studies have also preferred this relati-vely simple method of scoring (30, 32, 34,35). Arguments against the use of V.A.S.scales include the contention that unidi-mensional scales can never convey the com-plexity of the pain experience. It is of cour-se well known that pain has clear emotionaland affective components. Subjects mightalso use these scales to express the variouscomponents of their discomfort. We havetried to prevent this by dividing up the painexperience into a daytime and a nighttimesections, and by bringing in the affectiveand emotional components elsewhere onthe scoring form (see Appendix 1).

The pain score measurements show theeffect of laser treatment to be most pro-nounced in the short term. After seventeendays, i.e. at the end of the experiment, thesubjects in the laser therapy group still sho-wed a larger decrease in complaint scores,but the difference had almost disappeared.Thus, laser treatment especially seems toaccelerate recovery. The differences in theaverage decrease in pain scores for daytimeand nighttime after five days is not easy toexplain. A possible explanation might bethat the injured foot is not in use during thenight, thus causing less pain. It was alsofound that after five days the laser therapygroup is almost free of pain at night, whilethe other groups still feel pain. This seemsto be a clear effect of laser therapy.

As regards the impairment of sports partici-pation, the laser group also appeared to doslightly better than the other groups, al-though the effect was much less pronoun-ced than for the decrease in pain scores.Impairment of sports participation was as-sessed by means of V.A.S. scales as well.These scales are reasonably reliable in mea-suring pain scores, but it is not clear wheth-er they are equally reliable in assessing thedegree of impairment of sports participati-on. Perhaps the use of a dichotomous varia-

6

EFFECT OF LASER THERAPY ON ANKLE SPRAINS

ble would have been more appropriate hereafter all.

Another possible explanation for the lesspronounced differences in impairment ofsports participation could be that patientswill in general not actively engage in sportswithin five days after rupture of an ankleligament. But after seventeen days, someengagement m sports activities is found tobe possible. In other words, five days afterthe start of the therapy may be too brief aperiod for assessing impairment of sportsparticipation. Another difficult fact to ex-plain is that, after seventeen days, therewas hardly any difference between the laserand placebo groups in the impairment ofsports participation. It is hard to see whythere should be a placebo effect with regardto impairment of sports participation, butnone with regard to pain experience. This isprobably a chance finding.

Another point of discussion is the need fora window in the taping. Some physiothera-pists still apply laser therapy through anintact taping. Previous studies have shownthis to be impossible. Even one layer oftaping reduces the penetrative energy oflow and medium frequency lasers by asmuch as 70%, and with each subsequentlayer the energy decreases quadratically.Bearing in mind that a Coumans taping caneasily consist of five or six layers, it will beclear that any effect of laser therapy willthereby be reduced practically to zero.Hence in our opinion a window in the ta-ping is an absolute necessity for laser treat-ment. The window we made over the painpoint, with a diameter of 1 cm, was foundnot to affect the quality of the taping (24).

Finally it must be observed that a lasertherapy in accordance with our criteria ishighly time-consuming, and hence ratherexpensive. The duration of each treatmentis short, but the patient has to come in fortreatment frequently. It may be questionedwhether the balance of costs and gains forsuch therapy would be positive. There may,however, be an economic advantage if lasertherapy means that some patients can goback to work (sports) sooner.

Conclusion

In patients with an acute ankle sprain, lasertherapy, applied in accordance with ourcriteria, results in a more rapid reduction ofpain levels, especially at night. A more

rapid return to work (sports) also appearspossible. However, this will have to betested in a further study.

ReferencesASA med.-laser, Laser and magnetic fields in

medicine: technical information and applicationfields. Alta Villa (Italia). 1985.

Bahn, dr. J., Sechs Jahre erfahrung mitLasertherapie. *

Canata, G. L. et al., Laser therapy in therehabilitation of injured athletes, Inst. os Sportsmedicine, Turin.

De Cuyper, H. J. A., Het gebruik van laser inde fysiotherapie, De Tijdstroom, Lochem, 1984.

De Cuyper, H. J. A., Het gebruik van laser inde fysiotherapie, benaderd door middel van eenopen trial, Ned. Tijds. Fysiot. 95, 2, 29-34, 1985.

Fysiomed, Med. Electronica, Edegem (B),1986.

Greathouse, D. G. et al., Effects of clinicalinfrared laser on superficial radial nerveconduction, Phys. Therapy 65, no. 8, 1184-1187,1985.

Lievens, P., Heilzaam licht, laser; nietongevaarlijk, maar hoopgevend, EOS-magazine,17-22, okt. 1985.

Lievens, P., Lasertherapie (dee11), Ned.Tijds. Fysiot. 96, 2, 135-139, 1986.

Lievens, P., Lasertherapie (deel2), Ned.Tijds. Fysiot. 96, 6, 140-142, 1986.

Lievens, P., Lasertherapie, lezing, 15 feb.1986.

Mester, E., Der biostimulatieve Effekt vonLaser-Strahlen. *

Poldi, H., Lasertherapie in derSportmedizin. *

Pratzel, H., Biochemische Lichteffektedurch Laser. *

Pratzel, H. et al., Zum einfluf3 vonmonochromatischer Rotlichtbestrahlung (Laser632.8 nm) auf ein epidermalesStoffwechslungsmodell, Z. Phys. Med. Baln.Med. Klin. 13, 227-234, 1984.

Snijder-Mackler, L. et al., Effect of Helium-Neon laser on musuloskeletal triggerpoints, Phys.Therapy 66, 7, 1087-1089, 1986.

Taghawinejad, M. et al., Lasertherapie inder Behandlung kleiner Gelenke bei chronischerPolyarthritis, Z. Phys. Med. Baln. Med. Klin.14, 402-408, 1985.

J. Tronic Medical Laser, werkprotocol,praktische handleiding voor het gebruik vanmedische helium- en infra rood laser, SchreuderInstrum., Utrecht, 1986.

Lezing congres, Lasertherapie, realiteit entoekomst, deel I en 2, Nijmegen, 7 juni 1986.

Warnke, U., Dosis-wirkungseffekte des 904-

nm Laserhchtes auf Zellen and die physiologischeBedeutungfirr den Organismus, Universitat desSaarlandes, Saarbriicken.

Apeldoorn, A. T. et al.,Verwetenschappelijking van de fysiotherapie, eenkritische analyse van de discussies, Ned. Tijds.Fysiot., 95, 105-111, 1984.

Aufciemkampe, G. et al., Kwaliteit vaneffeconeting in de fysiotherapie, ecologischevaliditeit in het wetenschappelijk onderzoek,Ned. Tijds. Fysiot., 95, 123-131, 1985.

Vergen, A. van e.a., Toetsbarefysiotherapie, over uniforme registratie in defysiotherapie, SWSF, Tegelen en Deventer,1986.

Bie, R. A. de, Steenbruggen, R. A.,Lasertherapie, een effektonderzoek, uitg. S.O.S.Deventer, 1987.

Bouter, L. M., Dongen, M. C. J. M. van.Epidemiologisch Onderzoek; opzet eninterpretatie, Bohn, Scheltema & Holkema,Utrecht, 1988.

Bouter, L. M., Knipschild, P. G., Hetexperiment als paradigma voor interventie-onderzoek in de fysiotherapie, Ned. T.Fysiotherapie 97 (1987) 56-61.

Dereijcke, J. C. J. e.a., De zorg om dekwaliteit van de zorg in de fysiotherapie,Deventer, 1981.

Leeuwen, L. G. D. van, Pijn als verschijnselin fysiologische, psychologische en filosofischebetekenis, Ned. Tijds. Fysiot., 96, 70-73, 1986.

Meijer, 0. G. Artikelen in Issue;Methodologie en validiteit van wetenschappelijkonderzoek, kwartaaluitgave SWSF, 1984/1985.

Melzack & Wall, textbook of pain, chapter11: endogenous pain control mechanisms, H. L.Fields, A. I. Basbaum, and chapter 1.17: Testingpain mechanisms in persons in pain, A. E.Reading.

Bayersdorf, doorlaatbaarheidsonderzoekvan laserstralen door tape; in opdracht van R. A.de Bie en R. A. Steenbruggen, Hamburg, 1986.

Raad v. Gezondheidsresearch,Internationale classificatie van stoornissen,beperkingen en handicaps, T.N.O., 1980. ,

Revill, e.a., Mc-gill Pain Questionnaire vs.V.A.-scales, 1976.

Tromp, J. M. H. e.a., De aanpak vanonderzoek, Bohn, Scheltema en Holkema,Utrecht/Antwerpen, 1985.

Ven, A. van der, Inleiding in deschaaltheorie, Van Loghum Slaterus, Deventer,1977.

Winkel, D., Weke delen aandoeningen vanhet bewegingsapparaat, deel 2 diagnostiek,Bohn, Scheltema en Holkema, Utrecht, 1984.37. Voorhoeve P., De fysiologie van de pijn, Pijnen pijnbehandeling, De Tijdstroom, Lochem,1985.

* found in readers; specific references unknownto the authors