Short-term Effects of High-Intensity Laser Therapy Versus Ultrasound Therapy in the Treatment of...

Short-term Effects of High-IntensityLaser Therapy Versus UltrasoundTherapy in the Treatment of PeopleWith Subacromial ImpingementSyndrome: A Randomized Clinical TrialAndrea Santamato, Vincenzo Solfrizzi, Francesco Panza, Giovanna Tondi,Vincenza Frisardi, Brian G. Leggin, Maurizio Ranieri, Pietro Fiore

Background. Subacromial impingement syndrome (SAIS) is a painful conditionresulting from the entrapment of anatomical structures between the anteroinferiorcorner of the acromion and the greater tuberosity of the humerus.

Objective. The aim of this study was to evaluate the short-term effectiveness ofhigh-intensity laser therapy (HILT) versus ultrasound (US) therapy in the treatment ofSAIS.

Design. The study was designed as a randomized clinical trial.

Setting. The study was conducted in a university hospital.

Patients. Seventy patients with SAIS were randomly assigned to a HILT group ora US therapy group.

Intervention. Study participants received 10 treatment sessions of HILT or UStherapy over a period of 2 consecutive weeks.

Measurements. Outcome measures were the Constant-Murley Scale (CMS), avisual analog scale (VAS), and the Simple Shoulder Test (SST).

Results. For the 70 study participants (42 women and 28 men; mean [SD]age�54.1 years [9.0]; mean [SD] VAS score at baseline�6.4 [1.7]), there were nobetween-group differences at baseline in VAS, CMS, and SST scores. At the end of the2-week intervention, participants in the HILT group showed a significantly greaterdecrease in pain than participants in the US therapy group. Statistically significantdifferences in change in pain, articular movement, functionality, and muscle strength(force-generating capacity) (VAS, CMS, and SST scores) were observed after 10treatment sessions from the baseline for participants in the HILT group comparedwith participants in the US therapy group. In particular, only the difference in changeof VAS score between groups (1.65 points) surpassed the accepted minimal clinicallyimportant difference for this tool.

Limitations. This study was limited by sample size, lack of a control or placebogroup, and follow-up period.

Conclusions. Participants diagnosed with SAIS showed greater reduction in painand improvement in articular movement functionality and muscle strength of theaffected shoulder after 10 treatment sessions of HILT than did participants receivingUS therapy over a period of 2 consecutive weeks.

A. Santamato, MD, is AssistantProfessor, Department of PhysicalMedicine and Rehabilitation, Uni-versity of Foggia, Foggia, Italy.

V. Solfrizzi, MD, PhD, is AssistantProfessor, Memory Unit, Centerfor Aging Brain, Department ofGeriatrics, University of Bari, Bari,Italy.

F. Panza, MD, PhD, is AssistantProfessor, Memory Unit, Centerfor Aging Brain, Department ofGeriatrics, University of Bari, Poli-clinico, Piazza G Cesare, 11,70124 Bari, Italy. Address all cor-respondence to Dr Panza at:[email protected].

G. Tondi, MD, is affiliated with theDepartment of Neurological andPsychiatric Sciences, University ofBari.

V. Frisardi, MD, is affiliated withthe Memory Unit, Center for Ag-ing Brain, Department of Geriat-rics, University of Bari.

B.G. Leggin, PT, DPT, OCS, isAdvanced Clinician II, Good Shep-herd Penn Partners, Penn Presby-terian Medical Center, Philadel-phia, Pennsylvania.

M. Ranieri, MD, is Assistant Profes-sor, Department of Neurologicaland Psychiatric Sciences, Univer-sity of Bari.

P. Fiore, MD, is Professor, Depart-ment of Physical Medicine and Re-habilitation, University of Foggia.

[Santamato A, Solfrizzi V, Panza F,et al. Short-term effects of high-intensity laser therapy versus ultra-sound therapy in the treatmentof people with subacromial im-pingement syndrome: a random-ized clinical trial. Phys Ther. 2009;89:643–652.]

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Subacromial impingement syn-drome (SAIS) is the entrapmentof the supraspinatus muscle

tendon between the anteroinferiorcorner of the acromion and thegreater tuberosity of the humerus.1

This entrapment is responsible fordegenerative lesions of the tendon.Several pathoetiological mechanismshave been proposed; these includecontinuous lesions caused duringthe movement of the arm by sub-acromial contact, the subcoracoidspace, the coracoacromial ligament,and the coracoacromial articulation;alteration of acromial morphology2;alteration of arterial vascularizationof the humeral head3–5; overuse syn-drome; and alteration of the tensileproperties of the supraspinatustendon.6

Subacromial impingement syndromeis characterized by severe pain in theanterior-posterior and lateral shoul-der, extending to the deltoid andbiceps areas. The painful symptomsincrease at night and during abduc-tion, forced internal rotation, andresisted motions. Neer7,8 described3 stages of impingement. Stage Iimpingement is characterized byedema and hemorrhage of the sub-acromial bursa and rotator cuff andtypically is found in patients who areless than 25 years old. Stage II im-pingement represents irreversiblechanges, such as fibrosis and tendi-nopathy of the rotator cuff, and typ-ically is found in patients who are 25

to 40 years old. Stage III impinge-ment is marked by more-chronicchanges, such as partial or completetears of the rotator cuff, and usuallyis seen in patients who are more than40 years old.

Management of this pathology in-cludes numerous interventions,depending on pain severity andanatomopathological classification.Analgesic and nonsteroidal anti-inflammatory drugs,9 steroid injec-tions,10 and physical therapy (ultra-sound [US] therapy, laser therapy,manual therapy, extracorporealshock wave therapy, interferentialcurrent therapy, and acupunc-ture)11–22 have been reported, oftenwith mixed results. Systematic re-views of clinical trials have demon-strated little benefit from nonsteroi-dal anti-inflammatory drugs andsteroid injections; some studies havesuggested various physical agentsto be effective in minimizing thesymptoms by reducing inflamma-tion.23 Although pain can reducetheir efficacy, rehabilitative exerciseapproaches for the treatment of SAISinclude active and passive range ofmotion (ROM) exercises, stretching,Codman exercises, and isometricand isotonic exercises.19,23,24 The ef-fectiveness of conservative treat-ment is mixed, and surgical treat-ment may be indicated in casesresistant to conservative treatment.25

Several systematic reviews have sug-gested that physical therapy has notprovided unequivocal results be-cause of the notable variability ofanatomopathological lesions.11–22 Inparticular, limited evidence has sug-gested that exercise, joint mobiliza-tion, and laser therapy are effectivein decreasing pain and improvingfunction in patients with SAIS.20,22

Some systematic reviews have re-ported the limited effectiveness ofUS therapy for this condition.20,21

However, other studies have shownUS therapy to be effective in improv-

ing the symptoms.26,27 According tothe recommendations of the Phila-delphia Panel, an expert panel onselected rehabilitation interventionsfor shoulder pain, US therapy is anacceptable physical therapy inter-vention for SAIS.16

Laser therapy is based on the beliefthat laser radiation (and possiblymonochromatic light in general) isable to alter cellular and tissue func-tions in a manner that is dependenton the characteristics of the light it-self (eg, wavelength, coherence).28

By definition, low-intensity lasertherapy (LILT) (often also known as“low-energy” or “low-power” lasertherapy) takes place at low radiationintensities. Therefore, it is assumedthat any biologic effects are second-ary to the direct effects of photonicradiation and are not the result ofthermal processes.29 More recently,high-intensity laser therapy (HILT),which involves higher-intensity laserradiation and which causes minorand slow light absorption by chro-mophores, has been used. This ab-sorption is obtained not with con-centrated light but with diffuse lightin all directions (scattering phenom-enon), increasing the mitochondrialoxidative reaction and adenosinetriphosphate, RNA, or DNA produc-tion (photochemistry effects) and re-sulting in the phenomenon of tissuestimulation (photobiology effects).30

Some systematic reviews and ran-domized clinical trials have sug-gested that LILT could be an effec-tive physical therapy intervention fordecreasing pain and functional lossor disability for patients withSAIS20,31,32 or could have analgesicand tissue repair actions.33 None-theless, the effectiveness of lasertherapy is still in question becauseLILT has not provided convincing re-sults in patients with shouldertendinopathies.34,35

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High-Intensity Laser Therapy Versus Ultrasound Therapy for Subacromial Impingement Syndrome

644 f Physical Therapy Volume 89 Number 7 July 2009

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Few studies have been conducted tocompare the effectiveness of differ-ent physical therapies36 because ofthe difficulty in selecting homoge-neous groups of patients to reducethe variability of the results. To ourknowledge, no studies to date havebeen conducted on the possible ef-fects of HILT on SAIS. The aim of thepresent study was to evaluate theshort-term effectiveness of 2 differ-ent physical therapy modalities inthe treatment of SAIS: HILT and UStherapy.

MethodSetting and ParticipantsConsecutive outpatients attendingthe Department of Physical Medicineand Rehabilitation, University of Fog-gia, from September 2006 to July2007 were invited to participate inthe study. Patients had experiencedshoulder pain for at least 4 weeksbefore the study. Diagnostic criteriafor SAIS were the presence of shoul-der pain, pain on abduction of theshoulder with a painful arch, a posi-tive impingement sign (Hawkinssign),37 and a positive impingementtest (relief of pain within 15 minutesafter the injection of a local anes-thetic [bupivacaine, 5 mL]) into thesubacromial space). All patients alsowere evaluated by ultrasonographyor magnetic resonance imaging ofthe shoulder to confirm the diagno-sis of stage I or II.7 We used thediagnostic criteria for ultrasonogra-phy described by Naredo and col-leagues.38 This technique included adynamic examination of the su-praspinatus tendon obtained bymoving the patient’s arm from a neu-tral position to 90 degrees of abduc-tion to detect encroachment of theacromion into the rotator cuff.

Patients were excluded from thestudy if they met any of the followingcriteria: anesthetic or corticosteroidinjections within 4 weeks of studyenrollment, surgery or previous frac-tures of the humeral head of the af-

fected shoulder, impaired rotation inthe glenohumeral joint (as measuredwith goniometry), a history of acutetrauma, known osteoarthritis in theacromioclavicular or glenohumeraljoint, calcifications exceeding 2 cmin the rotator cuff tendons, signs of arupture of the cuff, cervical myofas-cial pain syndrome, radicular pain,inflammatory rheumatic disease, sys-temic lupus erythematosus, diabetesmellitus type I or II, thyroid dysfunc-tions, pacemaker, neurological pa-thologies, or anxiety-depressionsyndromes.

Patients received no other physicaltherapy intervention for shoulderpain during the study or in the 4 to 5weeks before the study. After a com-plete description of the study wasprovided, written informed consentwas obtained from all subjects ortheir relatives. The participants wereinstructed to avoid analgesic or anti-inflammatory drugs for the durationof the treatment and to abstain fromthe execution of painful activities ofdaily living involving the affectedshoulder. The participants kept adaily log of analgesic or anti-inflammatory drug intake during thestudy period.

A total of 85 consecutive patients (50women and 35 men) were screenedfor study eligibility. At the end of theevaluation, 70 patients who were af-fected by SAIS (Neer stage I or II, 45right shoulders and 25 left shoul-ders), had subacute or chronic pain,fulfilled the selection criteria, agreedto participate, and signed informedconsent statements were enrolled inthe study (42 women and 28 men;mean age�54.1 years, SD�9.0,range�35–69; mean time since on-set of pain�8.4 months, SD�9.8).These participants were randomlyassigned to 2 groups: a group of 35participants received HILT (20women and 15 men), and a group of35 participants received US therapy(22 women and 13 men). Reasons

for exclusion are shown in the Fig-ure, which is a flow diagram of par-ticipant recruitment and retention.No participant reported taking anal-gesic or anti-inflammatory drugs dur-ing the study. All 70 participantscompleted the trial and were in-cluded in the analysis.

Outcome MeasuresAll of the participants in the presentstudy were evaluated with a visualanalog scale (VAS),39 the Constant-Murley Scale (CMS),40 and the SimpleShoulder Test (SST).41 The VAS isused to measure pain on a 10-cmhorizontal axis between a left end-point of “no shoulder pain” and aright endpoint of “worst pain ever.”The distance is measured, and pain isrecorded on a 10-point scale.39 In theacute pain setting, the VAS has beenshown to have very good test-retestreliability (intraclass correlation co-efficient [ICC]�.99)42; this scale gen-erally is accepted as a valid measureof acute pain, with good constructvalidity.43,44 At a recent consensusmeeting of the Initiative on Methods,Measurement, and Pain Assessmentin Clinical Trials (IMMPACT), the re-sults of several studies on this issuewere considered. It was suggestedthat raw score changes of approxi-mately one point or percentagechanges of approximately 15% to20% represent the minimal clinicallyimportant difference (MCID) for theVAS and other, similar numerical rat-ing scales (0–10) for pain intensity.45

The CMS is a 100-point scoring sys-tem in which 35 points are derivedfrom a patient’s report of pain andfunction.40 The remaining 65 pointsare allocated to a quantitative assess-ment of ROM and strength (force-generating capacity). The self-reportassessment includes a single item forpain (15 points) and 4 items for ac-tivities of daily living (work, 4 points;recreation, 4 points; sleep, 2 points;and ability to work at various levels,10 points). The quantitative assess-



ment includes ROM (forward eleva-tion, 10 points; lateral elevation, 10points; external rotation, 10 points;and internal rotation, 10 points) andpower (scoring is based on thenumber of pounds of pull a patientcan resist in abduction to a maxi-mum of 25 points).40 This tool hasgood psychometric properties; the

CMS score reflects shoulder functionwith accuracy, test-retest reliability(ICC�.80),46 and reproducibility.47

Unfortunately, to date, there are nostudies providing data on the MCIDfor the CMS, despite the fact that forthis tool, error estimates (95% confi-dence interval [CI] of the standarderror of measurement [SEM]�

�17.7)46 and responsiveness (stan-dardized response mean�0.59),48

that is, the ability of a measure todetect change over time, have beenreported.

The SST is a series of 12 questionswith dichotomous “yes” or “no” re-sponse options. One group of ques-

Figure.Flow diagram of recruitment and retention of participants with subacromial impingement syndrome for ultrasound therapy andhigh-intensity laser therapy.



tions pertains to pain, and a secondgroup of questions relates to func-tion. Strength and ROM are not di-rectly evaluated. A theoretical “nor-mal” shoulder would result in a “yes”answer to all 12 questions. The goalof the SST is to compare pain andfunction before and after treat-ments.41 Content, criterion, and con-struct validity have been measuredfor the SST.49 Test-retest reliability(ICC�.99),50 internal consistency(Cronbach alpha�.85),51 error esti-mates (95% CI of the SEM��22.8,calculated from a converted scorerange of 0–100),51 and respon-siveness (standardized responsemean�0.82 and effect size�.83)have been reported for the SST. Un-fortunately, at present, there are nodata on the MCID for the SST.

RandomizationAfter the baseline examination, par-ticipants were randomly assigned toreceive HILT or US therapy. Con-cealed allocation was performedwith random numbers generatedfrom the Web site http://www.random.org/ before the beginning ofthe study. The procedure RandomInteger Generator allowed us to gen-erate random integers. A priori itgenerated 100 random integers and,before the beginning of the study,the randomization number was al-ready present. Individual, sequen-tially numbered index cards with therandom assignments were prepared.The index cards were folded andplaced in sealed opaque envelopes.A physician who was unaware ofthe baseline examination findingsopened the envelopes to attributethe interventions according to thegroup assignments.

InterventionsThe protocol involved the applica-tion of 2 different forms of physicaltherapy modalities for a total of 10treatment sessions over a period of 2consecutive weeks (5 days perweek). A physiatrist (A.S.) with 6

years of experience provided HILT,and a physical therapist with 7 yearsof experience provided US therapy.

Participants in the HILT group re-ceived HILT with a neodymium-yttrium aluminum garnet laser thathas a pulsating waveform producedby an HIRO 1.0 device (ASA srl*).The treatment consisted of a highpeak power (1 kW), a wavelength of1,064 nm, a maximum energy for asingle impulse of 150 mJ, an averagepower of 6 W, a fluency of 760mJ�cm2, and a duration for the singleimpulse of less than 150 millisec-onds. A pulsating waveform (5,000W/cm2) can transfer 1,000 timesmore light intensity to the soft tis-sues than a continuous waveform (5W/cm2) with the same averagepower (1 W) and bright spot (0.2cm2). These ultrashort impulses es-tablished a deep action in biologicaltissue (3–4 cm), with a homoge-neous distribution of the light sourcein the irradiated soft tissue but with-out excessive thermal enhance-ments. A standard handpiece en-dowed with fixed spacers was usedto ensure the same distance to theskin and verticality of 90 degrees tothe zone to be treated with a bright-spot diameter of 5 mm. Three phasesof treatment were performed forevery session.

An initial phase involved fast manualscanning (100 cm2/30 s) of the zonesof muscular contracture, particularlyfor the upper trapezius and deltoidmuscles and anteriorly for the pecto-ralis minor muscle. Scanning wasperformed in both transverse andlongitudinal directions with the armpositioned in internal rotation andextension to expose the rotator cuff.In this phase, a total energy dose of1,000 J was administered.

An intermediate phase involved ap-plying the handpiece with fixed

spacers vertically to 90 degrees onthe trigger points until a pain reduc-tion of 70% to 80% was achieved. Inthis phase, the mean energy dosewas 50 J. A final phase involved slowmanual scanning (100 cm2/60 s) ofthe same areas treated in the initialphase until a total energy dose of1,000 J was achieved.

Three steps were predicted in thestarting/initial and final phases of thetreatment; the fluencies used were510, 610, and 710 mJ/cm2, respec-tively. Therefore, the total dose ofenergy administered was approxi-mately 2,050 J. The time to apply all3 stages of HILT was approximately10 minutes.

Participants in the US therapy groupreceived continuous US for 10 min-utes with a SONOPLUS 492,† a de-vice that was operated at a frequencyof 1 MHz, an intensity of 2 W/cm2,and a duty cycle of 100%. The trans-ducer head had an area of 5.8 cm2

and an effective radiating area of 4.6cm2. The treating physical therapist,using the technique of slow circularmovements, applied the transducerhead over the superior and anteriorperiarticular regions of the partici-pant’s glenohumeral joint and on theshoulder trigger points, covering anarea of approximately 20 cm2 (4times the effective radiating area).Participants were assessed by a phys-ical medicine physician at the base-line (before the first treatment ses-sion) and at the end of physicaltherapy (after the last treatment ses-sion). Moreover, the pretreatmentand posttreatment clinical evalua-tions (VAS, CMS, and SST) were doneby the same tester. It is important toremember that the physicians whoperformed the clinical evaluations ofthe participants were unaware of thegroup assignments. All participantsin the 2 treatment groups received

* Arcugnano, Via Volta, 9 Vicenza, Italy.

† Enraf-Nonius BV, Vareseweg 127, Rotter-dam, the Netherlands.



10 treatment sessions in the 2-weekperiod.

Sample Size DeterminationThe sample size and power calcula-tions were performed with nQueryAdvisor statistical software (version6.0).‡ Sample sizes of 35 for the HILTgroup and 35 for the US therapygroup achieved a power of 80% todetect a difference of 50% in the VAS(score�1.0 point) in a design with 2repeated measurements when thestandard deviation was 1.5, the cor-relation between observations forthe same participant was .7, and thealpha level was .05.

Data AnalysisAll analyses were performed withSAS statistical software (version9.1).§ Frequency distributions aswell as means and standard devia-tions were used for descriptive pur-poses. At the baseline, differences inage and time since the onset of painbetween treatment groups were

analyzed with an independent2-sample t test and a Mann-WhitneyU test, respectively. Differences insex and SAIS Neer stage frequencydistributions were evaluated with aPearson chi-square test. Differencesbetween treatment groups in changescores at the baseline and after 10treatment sessions over a period of 2consecutive weeks were analyzedwith an independent 2-sample t test.Repeated measurements obtainedbefore and after treatments withingroups were analyzed with a paired-matched t test. A 2-way repeated-measures analysis of variance(ANOVA) was performed to estimatedifferences between (group effect)and within (time and time � groupeffects) treatment groups for eachstudied outcome. The statistical in-ferences were adjusted according toBonferroni inequality (P values cor-responding to .05/6�.008 and .01/6�.002). The alpha level for signifi-cance was set at .05.

Role of the Funding SourceThis work was supported by the Ital-ian Longitudinal Study on Aging(ILSA) (Italian National Research

Council-CNR-Targeted Project onAging grants 9400419PF40 and95973PF40). The funding agencieshad no role in the design, conduct,or reporting of the study.

ResultsTable 1 summarizes the baseline clin-ical and demographic characteristicsof the subjects enrolled in the study.Table 2 summarizes test perfor-mance at the baseline and at thecompletion of the study (after 10treatment sessions over a period of 2consecutive weeks) for each treat-ment group. A significant change intest performance was observed inboth groups after the initiation oftreatments (VAS: ANOVA F statisticfor a time effect�435.73; df�1,68;P�.001; CMS: ANOVA F statisticfor a time effect�800.98; df�1,68;P�.001; SST: ANOVA F statistic fora time effect�366.38; df�1,68;P�.001). Moreover, we found a sig-nificant difference in VAS scoreswhen we compared US therapy withHILT (ANOVA F statistic forgroups�10.863, P�.002), but wefound no significant differences inCMS and SST scores between treat-ments. Finally, statistically signifi-cant differences in changes fromthe baseline after 10 treatment ses-sions by treatment group were ob-served (VAS: ANOVA F statistic for atime � group effect: 34.07; df�1,68;P�.001; CMS: ANOVA F statisticfor a time � group effect�22.72;df�1,68; P�.001; SST: ANOVA Fstatistic for a time � group ef-fect�7.88; df�1,68; P�.007).

Multiple comparisons analyzing dif-ferences within groups were per-formed for the HILT group and theUS therapy group, and the results areshown in Table 2. Multiple compar-isons analyzing differences betweengroups also are shown in Table 3.Finally, we analyzed differences inchange scores between groups after10 treatment sessions over a periodof 2 consecutive weeks; we found

‡ Statistical Solutions Ltd, 7B Airport East Busi-ness Park, Farmer’s Cross, Cork, Ireland(www.statsol.ie).§ SAS Institute Inc, PO Box 8000, Cary, NC27511.

Table 1.Baseline Demographic and Clinical Characteristics of Participants With SubacromialImpingement Syndrome (SAIS) in High-Intensity Laser Therapy (HILT) andUltrasound (US) Therapy Groups

CharacteristicHILT Group

(n�35)US Therapy Group

(n�35) P

Age, y

X (SD) 54.2 (8.2) 54.0 (9.8) .93a

Range 38–69 35–69

Time since onset of pain, mo

X (SD) 8.7 (8.8) 8.1 (10.8) .82b

Range 1–36 1–42

Sex (female/male) 20/15 22/13 .63c

Diagnosis (n)

SAIS Neer stage I 13 14 .81c

SAIS Neer stage II 22 21

a As determined by an independent 2-sample t test.b As determined by the Mann-Whitney U test.c As determined by the Pearson chi-square test.



statistically significant differences forVAS, CMS, and SST scores (Tab. 3).

DiscussionIn the present study, we comparedthe results obtained after 10 treat-ment sessions over a period of 2 con-secutive weeks with 2 differentphysical therapy modalities in sub-jects diagnosed with Neer stage I orII SAIS. The subjects treated withHILT showed a greater reduction inpain and more improvement in artic-ular movement, functionality, andmuscle strength of the affectedshoulder than the subjects treated

with US therapy (as measured withthe VAS, CMS, and SST). Significantdifferences in changes after 10 treat-ment sessions over a period of 2 con-secutive weeks from the baseline bytreatment group were observed. Inparticular, the difference in thechange in the VAS scores betweenthe groups (1.65 points) surpassedthe accepted MCID for this tool.47

Contrasting findings have been re-ported for US therapy and laser ther-apy in the treatment of SAIS andother shoulder disorders.11–21 Thereis little evidence that active thera-

peutic US is more effective than pla-cebo US for treating people withsoft-tissue disorders of the shoulder,including SAIS.17,20,21 Several au-thors20,52,53 have reported no differ-ences between true US and sham USfor subjects with soft-tissue disordersof the shoulder. Conversely, studiesby other researchers have supportedthe efficacy of US therapy in reduc-ing pain, improving activities of dailyliving, and improving quality oflife.26,27 In particular, Ebenbichlerand colleagues27 reported that 24daily applications of US therapy at2.5 W/cm2 (5 times per week for 3

Table 2.Test Performance at Baseline and After Intervention for Participants With Subacromial Impingement Syndrome in High-IntensityLaser Therapy (HILT) and Ultrasound (US) Therapy Groups: Evaluation Within Groups and Between Groupsa

Test HILT Group (n�35)US Therapy Group

(n�35)

Mean Differencein Change Scores

(95% CI)ActualP Value

Bonferroni-CorrectedP Valueb

VAS score

Baseline 6.28 (1.8) 6.6 (1.53) 0.29 (�1.10 to 0.52) .48 NS

After intervention 2.42 (1.42) 4.44 (1.37) �1.97 (�2.64 to �1.30) �.001 �.01

Mean difference inchange scores(95% CI)

3.86 (3.33 to 4.39) 2.17 (1.92 to 2.43)

Actual P value �.001 �.001

Bonferroni-correctedP valueb

�.01 �.01

CMS score

Baseline 63.22 (8.68) 63.08 (7.05) 0.14 (�3.63 to 3.92) .94 NS

After intervention 75.91 (7.02) 72.11 (6.95) 0.14 (�3.63 to 3.92) .03 NS


�12.69 (�13.94 to �11.43) �9.03 (�9.96 to �8.10)



�.01 �.01

SST score

Baseline 7.22 (2.28) 6.91 (2.24) 0.31 (�0.77 to 1.39) .56 NS

After intervention 9.68 (1.99) 8.74 (2.04) 0.94 (�0.02 to 1.91) .06 NS


�2.46 (�2.86 to �2.06) �1.83 (�2.04 to �1.62)



�.01 �.01

a Values are means (SDs) unless otherwise indicated. CI�confidence interval, VAS�visual analog scale, NS�not significant, CMS�Constant-Murley Scale,SST�Simple Shoulder Test.b The statistical inferences were adjusted according to Bonferroni inequality within groups.



weeks and then 3 times per week for3 weeks) reduced the painful symp-toms in patients with calcific tendi-nitis of the supraspinatus tendon; inaddition, the calcium deposits re-solved in 19% of patients in the UStherapy group and decreased by atleast 50% in 28% of the patients. Thevariability of shoulder disorders andvariations in the treatment intensity,duration, frequency, and location ofUS applications in previous studiescould explain, in part, these contrast-ing findings.20,26,27,52,53

Some authors20,31,32,34 have sug-gested that LILT used without otherphysical therapy modalities could behelpful in the management of SAIS.For a small group of patients withtendinitis of the supraspinatus ten-don, the data revealed that the pa-tients treated with LILT had lesspain, less secondary weakness, andless tenderness after the treatmentthan before.32 However, in anotherstudy of patients with shoulder ten-donitis, LILT had only a short-termbenefit for pain, self-reported func-tion, active ROM, stiffness, and re-striction after 2 weeks of treatmentwhen compared with a placebo la-ser.34 Furthermore, conflicting re-sults were demonstrated by Vecchio

and colleagues35 in a comparison ofpatients who had SAIS and weretreated with LILT and ROM exercisesand patients who were treated witha placebo laser and ROM exercises;at 4- and 8-week follow-up sessions,there was no difference betweengroups with regard to pain, ROM,function, or strength. A recent meta-analysis suggested analgesic and tis-sue repair actions of LILT,33 whereasanother study reported that 10 appli-cations of LILT for 2 weeks did notinduce significant pain relief and im-provements in articular function rel-ative to the findings for a group con-trol given a placebo.54 Therefore,although the current evidence isconflicting, it appears that LILT wasmore beneficial than a placebo whenapplied as a single intervention forparticipants with SAIS.

Our findings with HILT may lead topromising new therapeutic options.In the present study, the results ob-tained after 10 treatment sessionswith the experimental protocol sug-gested greater effectiveness of HILTthan of US therapy in the treatmentof SAIS. The participants treatedwith HILT showed a greater reduc-tion in pain and more improvementin articular movement, functionality,

and muscle strength of the affectedshoulder than the participantstreated with US therapy. No studieshave yet been conducted to comparethe effectiveness of these differentphysical therapies, but no therapeu-tic differences among US therapy,LILT, and combined treatments werenoted for tendon healing in rats.55

High-intensity laser therapy quicklyreduces inflammation and painfulsymptoms.56 It utilizes a particularwaveform with regular peaks of ele-vated values of amplitude and dis-tances (in time) between them todecrease thermal accumulation phe-nomena, and it is able to rapidly in-duce in the deep tissue photochem-ical and photothermic effects thatincrease blood flow, vascular perme-ability, and cell metabolism.57 TheHILT had an analgesic effect onnerve endings, but there was noevidence of a diminution ofinflammation.58,59

Limitations of the present study in-clude the lack of a control groupreceiving no treatment; this limita-tion constrains our ability to claimcause and effect. Participants in bothgroups may have improved simplybecause of the passage of time and

Table 3.Change in Test Performance Over Time From Baseline for Participants With Subacromial Impingement Syndrome in High-Intensity Laser Therapy (HILT) and Ultrasound (US) Therapy Groups: Evaluation Between Groupsa

VariableBoth Groups

(N�70)HILT Group

(n�35)US Therapy Group

(n�35)

Difference inMeans

(95% CI)ActualP Value

Bonferroni-CorrectedP Valueb

VAS score

X (SD) �3.01 (1.46) �3.86 (1.53) �2.17 (0.75) �1.69 (�2.27 to �1.12) �.001 �.01

% �48.89 �61.36 �33.04

CMS score

X (SD) 10.86 (3.68) 12.69 (3.64) 9.03 (2.70) 3.66 (2.13 to 5.19) �.001 �.01

% 17.19 20.06 14.31

SST score

X (SD) 2.14 (0.98) 2.46 (1.17) 1.83 (0.61) 0.63 (0.18 to 1.08) .006 �.05

% 30.30 33.99 26.45

a CI�confidence interval, VAS�visual analog scale, CMS�Constant-Murley Scale, SST�Simple Shoulder Test.b The statistical inferences were adjusted according to Bonferroni inequality (0.05/6�0.008 and 0.01/6�0.002).



the avoidance of strenuous activityfor the treatment period. We havecompared a new treatment option(HILT) with an accepted physicaltherapy modality, US therapy. As dis-cussed above, some studies haveshown US therapy to be effective inimproving symptoms26,27 and haveproposed this treatment as an ac-ceptable physical therapy modalityfor SAIS.16 Additionally, the fact thatthe participants in one group weretreated by a physical therapist andthe participants in another groupwere treated by a physiatrist is a lim-itation of the present study becausethe participants were randomly as-signed to physiatrist-HILT or physicaltherapist-US therapy groups. An-other limitation is the lack offollow-up data, which reduces theclinical application of our findingson the short-term effects of HILT andUS therapy in SAIS. Furthermore, ourprotocol of 10 treatment sessionsover a period of 2 weeks could bechallenging to apply in clinical prac-tice. Finally, notwithstanding thegood psychometric properties of the3 measurement tools used in thepresent study, we only have MCIDdata on the VAS, limiting our abilityto attribute a clinical significance tothe differences between groups ob-served with the CMS and the SST.However, the difference in thechange in the VAS scores betweenthe groups (1.65 points) surpassedthe MCID for this tool.45 On theother hand, the 95% CI of the SEMfor the CMS was �17.7 points,46 andthe between-group difference didnot surpass the SEM (3.8 points).Moreover, although the reliability ofthe SST has been reported to begood,60 a recent psychometric eval-uation of the CMS suggested that itsuse is acceptable when pretreatmentand posttreatment scores are deter-mined by the same tester,54 as in thepresent study.

ConclusionAlthough further studies are neededto confirm the effectiveness of phys-ical therapy interventions for SAIS,HILT was shown to have greater ben-efit for SAIS than US therapy in re-ducing pain and improving the artic-ular movement, functionality, andmuscle strength of the affectedshoulder. The results of the presentstudy are encouraging, but otherstudies with larger samples, longer-term findings, and possible compar-isons with other conservative inter-ventions or placebo control groupsare needed.

Dr Santamato provided concept/idea/re-search design. Dr Santamato and Dr Panzaprovided writing. Dr Solfrizzi provided datacollection. Dr Solfrizzi and Dr Panza pro-vided data analysis. Dr Tondi and Dr Frisardiprovided participants. Dr Leggin and DrFiore provided institutional liaisons. Dr Leg-gin and Dr Ranieri provided consultation (in-cluding review of manuscript before submis-sion). The authors thank Dr Sheila Abrusci forher help in editing the manuscript.

The study protocol received approval fromthe Institutional Review Board of the Univer-sity of Bari.

This work was supported by the Italian Lon-gitudinal Study on Aging (ILSA) (ItalianNational Research Council-CNR-TargetedProject on Aging grants 9400419PF40 and95973PF40). The funding agencies had norole in the design, conduct, or reporting ofthe study.

This article was received May 10, 2008, andwas accepted Aapril 6, 2009.

DOI: 10.2522/ptj.20080139

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