,~.

Techniques ill Fool alld Ankle S"rge/y 5(1):60-65, 2006 © 2006 Lippincott WilliallIs & Wilkins; Phi/adelphia-.----------.---------------------------------------------_. __ .__.~.---~-_.-""*

Shock Wave Therapy for Treatment of Footand Ankle ConditionsAlastair Younger, MB, ChB, FRCSCBe's Foot and Ankle ProgramProvidence Health Care

Department of OrthopaedicsUniversity of British ColumbiaVancouver, BC, Canada

!i£l AJBS'JrRA CT

Shock wave therapy is a relatively new treatment of footand ankle pain. An acoustic sound wave similar to oneused for lithotripsy can cause a hyperanalgesia effect re­ducing pain and can cause breakdown and neovasculari­zation of c1u'onically damaged tissue. T1u'ee commercialsources are available for musculoskeletal applications.To date, the treatment seams to be effective for soft tissuepain. Within the United States shock wave therapy hasbeen licensed for plantar fasciitis and has been usedoutside the United States for other foot and ankle

tendonopathies. The pain must be well localized to Iarea for effective treatment. This article reviews the

physics, indications, techniques, and documented out­comes to date.

Keywords: plantar fasciitis, shock wave therapy,extracorporeal, tendonitis, fasciitis

8Jl lIUSTOJl.UCAIL JP'ROSlPECrJlVE

Extracorporeal shock wave therapy (ESWT) was used

initially in th~ fragmentation of renal stones in thekidney and urinary tract for the treatment of renal colic.The first machine was produced commerciaJly byDornier in 1984.1.2 Stones in the gall bladder, pancreas,bile ducts, and salivary glands have been treated bylithotripsy using ESWT. Observation showed that while

in some cases th~ stone. did not fragment or pass, thepatient had significant symptom relief. The effect ofshock waves was used in an animal model in 1986 to

determine the effects on skin defect healing: Low doseshaving a positive effect and high doses inhibitinghealing.3 The tec1mology was applied thereafter to thetreatment of delayed bone healing and pseudoartlu'osisafter appropriate animal studies.3-5 Treatments startedin 1988, with 70 of 82 nonunions being successfullytreated.6 Other bony orthopedic applications included

Address correspondence and reprints request to: Alanstair Younger.MB. ChB. FRCSe, Suite SOD, 1144 BUlTard Street, Vancouver BeV5Z 2E8. E-mail: asyounger@shaw.ca.

loose hip artlu'oplasties, and osteochondrosis includingOCD lesions of the knee and talus, and Kohler, Perthes,

and Osgood-Schlatter diseases.3Subsequently, the treatment was applied to tendo­

nopathies including plantar fasciitis, shoulder impinge­ment, and tennis elbow.7•8 Dahmen3 wrote the first

paper in 1992 on shock wave treatment of tendonopa­thies, with 30 different syndromes being included in a512 patient series.

The urological generators were not ideal for muscu­loskeletal treatments, hence newer generations of im­pulse generators were developed for treatment ofmusculoskeletal conditions (Fig. 1). Siemens producesthe Soncur (Sonorex, Vancouver, British Columbia,

and Siemens, Erlagen, Germany), Dornier the EposUltra (Dornier Medtech America Inc, Kennesaw, GA,USA, and Dornier Medtech, Wessling, Germany), andHealthtronics the OssaTron (High Medical Technolo­gies, Lengwil, Switzerland, and Healthtronics, Austin,TX, USA). FDA approval has been granted forSonocur treatment of lateral epicondylitis. The EposUltra and OssaTron have been approved for treatment

of clu'onic plantar fasciitis with symptoms present for6 months and failure of conservative treatment.

The therapeutic ultrasound wave has a fast pressure riseand a high pressure maximum. This transfers energy tothe focused area within the patient. The shock wavegenerator must be coupled to the patient using a fluidbarrier. In urology this is achieved by immersing the'

patient in water. In the generators developed formusculoskeletal applications, the coupling has beenachieved using a water-filled diaphragm applied to theskin with acoustic gel placed on the skin surface. TIlegenerator and coupling device are all on the end'of anarticulating arm and on a mobile base, allowing "the ma­chine to be positioned to precisely deliver the shock waveto the area of discomfort.2

60 Techl1iques ill Foot al1d All/de Surge.)'

Shock Wave Therapy for Treatment of Foot and Ankle Conditions

~ iNDICA TIONS

interface is seen in rabbits 10 and in dogs. I I Within bone,high doses can cause avascular necrosis and hematomaformation in animal studies. Only hematoma formationhas been seen in doses used in patients.

tPr

Pmax

to

compression

P

t

rarefactionFIGURE 2. The shock wave profile.

~DA appI:oval has been obtained for plantar fasciitisfor OssaTron in 2000 (high energy), Dornier Epos forplantar fasciitis in 2002, and Siemens Sonocur (lowenergy) for lateral epicondylitis in 2002. The FDAapproval includes at least 6 months of existence ofdisease and failure of conservative treatment.

Soft Tissue EffectsWithin muscle and tendons, shock wave increases TGF­

p and IL-I expression in rat Achilles tendonitis model. 12

Paratendinous fluid is also seen after treatment, and anincreased diameter in the tendon. Histological changesincluded fibrinoid necrosis, fibrosis in the paratenon,ancl infiltration of inflammatory cells.13

Shock wave therapy is thought to be effective inpain relief by a counter irritation or hyperstimulationanalgesia effect. For low doses the hyperstimulationactivates nonmyelinated C fibers, causing inhibition offurther pain reception by inhibitor fibers. At moderateenergy intensity, pain may be relieved by direct andindirect mechanisms. The direct effect includes disrup­tion of the mechanical source of pain, such as scarformation in the Achilles insertion, or calcificationwithin a tendon or fascia. Neovascularization removes

the breakdown products of the scar or calcification. In­directly, including the hyperstimulation analgesia, vas­cularization and macrophage immigration inducescellular repair of the degenerate tissue.2

Bone Effects

Within bone this cellular damage results in micro­fractures and osteoblast stimulation. Hematomas can becreated. Increased neovascularization at a bone tendon

The actual shock wave is generated within themachine by either an electromagnetic, electrohydraulic,or piezoelectric system. The electrohydraulic wave isgenerated similar to an automobile spark plug; thepiezoelectric system uses oscillation of quartz crystals,and the electromagnetic generator uses deflection of ametal membrane similar to a speaker for a soundsystem? The source causes a membrane to be rapidlyrepelled, the shock wave traveling through water to anacoustic focusing lens. The shock wave has a suddenpressure increase causing the local tissue effect (Fig. 2).The lens focuses the shock wave to a focal point at aknown distance from the lens. All devices have water­

filled coupling bellow that can vary the distance betweenthe lens and the skin surface. This allows the operatorto vary the depth of the focal point within the patient.Shocks can be varied in intensity and frequency.9

Subsequent developments have focused on methodsof application and determining the conect dose size andfrequency to achieve a maximal clinical effect.

Cellular EffectsThe effect at the cellular'level is related to dose, with

high energy levels causing significant cell necrosis.Lower doses cause cellular changes. These includeenhanced membrane permeability, mitochondrial, endo­plasmic reticulum, and cell nucleus changes. Theseinclude vacuolation within the cytoplasm and lesions inthe actin and vimentin filaments?

FiGlJiBE 'j. A patient undergoing low dose shock wavetherapy treatment of the heel showing the coupling head,bellows, and gel.

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Younger

Outside the United States, shock wave therapywithin foot and ankle is used to treat Achilles tendonitis,

Morton neuroma, stress fractures, peroneal, and tibialisposterior tendonitis. In general, shock wave therapy isused for treatment of enthesopathies, tendonopathies,and overuse injuries.

fii'.l CONTRAINDICATIONS

Patients on anticoagulants or with a known clottingdisorder have a relative contraindication to shock wave

therapy as bleeding may be stimulated by the treatment.Pregnancy is considered a contraindication as the effectof shock wave on pregnancy has not been evaluated.Infection in the site or an open wound over the treatmentsite excludes the patient from shock wave therapy.

Otherwise patients unable to. localize pain have arelative contraindication to treatment. These include

patients with Alzheimer disease or other brain con­ditions preventing pain localization, or patients withdiffuse pain, or many sites of pain making localizationof the origin impossible.

~ PRETREA TMENT PLANNING

Low energy shock wave therapy requires that the painbe well localized to 1 or 2 discrete areas. The area

should be identifiable by palpation. There should be ananatomic correlation to the pain, the area of pain shouldbe consistent, and the patient should be able tocooperate in the localization of the area of discomfort.

Patients should be imaged before treatment to ruleout any malignancy. This may include plain radiographsand MRI.

Conservative treatment should be exhausted before

treatment. For plantar fasciitis this should include anti­inflammatories, physiotherapy and stretching, activitymodification, and orthotics, but not necessarily steroidinjections. 14

Contraindications to treatment include poorly local­ized pain, pregnancy, malignancy, age under 18, andbleeding disorders. Patients on Coumadin should sus­pend anticoagulation if shock wave therapy is peIformedto prevent hematoma formation.

m TECHNIQUE OF TREATMENT

Types of Musculoskeletal SourceEnergy source may be low or high energy: Low energyis applied by a technician, requires no anesthesia orimaging, and has a lower cost using 3 treatment regimes.The lower energy sources allow the technician to focusthe signal onto the area of maximum discomfort as noanesthetic is used. The Sonocur plus is a low energysource.

High energy requires a physician to operate it andanesthesia is required as it is painful. Imaging is requiredto focus the beam. For the Epos Ultra local anesthetic isinstilled in the heel before treatment. For the Epos ultrauses an electromagnetic generator. The OssaTron uses a .spark plug. All generators use water-filled diaplu'agms tocontact the skin. The OssaTron is more painful andtherefore requires a greater degree of anesthesia, increas­ing the cost. The water-filled diaplu'agm can be changedin depth focusing the beam within the patient.

The operator can direct the shock wave at the area ofdiscomfort and can also vary the depth of penetration ofthe wave. For the Epos Ultra, the area of tenderness isidentified using clinical exam, and an ultrasound probe isused to confirm the positioning of the center of shockwave application. For the OssaTron, the area is identifiedbefore anesthesia and the physician directs treatment tothe area. The higher dose may result in a higher fieldbeing affected, causing a greater degree of pain relief.

For the Sonocur, direct feedback is used, as no anes­

thesia is required, the operator changing the depth anddirection of treatment to hit the area of maximum pain.

Gel is applied to the area to couple the diaphragm tothe· skin preventing shock wave attenuation. Thediaphragm of the device is applied to the skin and thedepth of penetration altered until the area of discomforthas been localized. This is harder to achieve for the

OssaTron. The Epos Ultra uses ultrasound to focus thebeam, whereas patient feedback is used for the Sonocur.The energy level of the shock wave is increased and2000 shocks are applied per treatment. The source isadjusted during treatment to ensure that the area ofmaximum tendemess is treated. The treatment is

repeated up to 3 times.

Complications-transientIn the FDA study, the patients reported a number ofadverse events. This included pain, nausea, and reactionat the application site, sweating, and dizziness. Somereactions were the same in the control group. Otherreported complications include petechiae, skin discolor­ation, dull pain, and paraesthesia.

Posttreatment ManagementPatients activity can be as tolerated after treatment. Oneof the major benefits of shock wave therapy is thatpatients can continue activities immediately after treat­ment and minimal time off work is required corrlpareclwith a surgical release. Adjuvant treatments aTe contin­ued during and after treatment" including ice andphysiotherapy. There is no literature to date document­ing any particular risk of rupture after shock wavetherapy so physiotherapy and activities are encouragedto be continued as normal.

Techniques i'l Foot alld A1zkle.SlIIge.y

Shock Wave Therapy for Treatment of Foot and Ankle Conditions

./

Delayed ImagingMRI before and immediately after treatment shows

increase in soft tissue oedema but not bone oedema:

high energy. 15

Ultrasound at 6 months shows significant attenua­

tion of signal after shock wave therapy compared withbefore-treatment approaches same as opposite side.

Thickness of plantar fascia correlated with the degree

of pain.16

IiiIJ S10MlVlARY OF OUTCOME DATATO DATE

Two papers have shown no difference between treat~

ment groups: one published in the lournal of theAmerican Medical Association,17 the second in the

British Medical Journal. IS Both used the Dornier Epos

Ultra with local anesthetic block. The lAMA paper used

a low dose versus regular dose treatment, and the BM]

article used a polyethylene foil in the control group.

Both papers studied patients early in the treatment orwith minimal symptoms, potentially confounding theresults. The lAMA article used 6 weeks instead of

6 months as an inclusion criterion. The BMJ article had

only 1 patient in each group going on to surgery and did

not outline the duration of prior treatment. Ultrasound

and MRI abnonnalities may not be the main area of pain

and as a result may have missed the source of pain.

Most papers apart from these 2 have shown suc­cessful outcome of treatment. The studies have been of

higher quality in general, being prospective and random­

ized controlled studies for the most part. The Cochranedatabase felt there was little evidence for its use but set a

very high standard for inclusion criteria for the papers. 19

Otherwise, weaker literature evidence presently exists

for the surgical treatment of planar fasciitis so that the

'fAnLE)' SIIIIIII/l1n' o(lJlDs/'eclil't' /,oper.\'f{,r I'/ulliorfilsciilis

44 nil

45 random

86 random

30 Random

Result---+ve

+veDecreasedfasciathickness-ve

+ve

+ve+ve+ve+ve+ve+ve?+ve+ve?+ve

+ve'

-ve-ve

crossRandom

blindedRandom

Random

Randomblinded

Randomblinded

2085

88

35

435

293

150

47256

322 random

165 Random

No. patients Design

115 Random

Dilte JonmalAuthorenergyStndy

2002

Journal of Bone and JointRompe21HighLow vs

Surgery

high dose1995

Archives of Orthopedic andRompe22HighLow vs no

Trauma Surgery

treatment

2003Archives of Orthopedic andHammerl6Shock wavePlantar fascia

Trauma Surgerytherapythickness

2002

JAMA Buckbinder17DornierLow vs highEpos Ultra2002

Foot & Ankle InternationalAlvarez23HighCase seJies2002

Journal of Foot and AnkleWangllHighCase series

Surgery 2002

Foot & Ankle InternationalOgdenl4allMeta-analysis2001

Clinical Orthopaedics andOgden24HighLow vs highRelated Research 2005

Journal of Orthopaedic Rompe25lowLocal anestheticResearch

vs no local

2003American Journal of SportsRompe26LowLow vs placebo

Medicine

runners2005

Journal of Foot and AnkleHyer27DornierCase series

Surgery Theodore28

Epos

2004

Foot and Ankle DomierTreatmentInternational

Eposvs sham

2004

Journal of Bone and JointOgden29HighTreatment

Surgery

energyvs sham

2003

Journal of Orthopaedic Speed30TreatmentResearch

vs sham

2003

Foot and Ankle InternationalLee3lLowTreatment

energy

vs sham

2003

Foot and Ankle InternationalHammer32Crossover2003

EMJ Haakel8Dornier

Crawfordl9

Epos

2003

Cochrane Database of Meta-analysisSystematic Reviews

DeJ'ice

Volume 5, Issue 1 63

Younger

conclusion of the Cochrane review needs to be taken incontext.

In the treatment of failed plantar fasciitis, thecomparative treatment, open surgery, has not had nearlythe same rigorous outcome analysis. The only compar­ative series on shock wave therapy against surgeryperformed was a study on lateral epicondylitis inworker's compensation patients. This study supportedthe use of ESWT over surgery but has not as yet beenpublished.2o Seventy-six percent of the ESWT groupreturned to work by 6 months compared with 30% in thesurgery group. Low dose source without anesthesia iseffective, and high dose with anesthesia is effective.Low dose with anesthesia is not effective, as shown in a

prospective randomized trial by Rompe?5 Summaries ofoutcomes to date are in Table 1.

!;B CONCLUSION

Shock wave therapy seems to be a viable treatmentalternative for plantar fasciitis. Outcome studies ingeneral have supported a positive outcome. Shock wavetherapy has been used for treatment of well-localizedtenonopathies and soft tissue pain outside the UnitedStates. For example, insertional Achilles tendonitis canbe treated with shock wave therapy as an alternative tosurgery. FDA approval for foot and ankle presently onlycovers plantar fasciitis. Shock wave therapy should beoffered as a second line of treatment to patients withplantar fasciitis, possibly before steroid injection, as thecomplication rates may be lower and the therapeuticeffect higher. Shock wave therapy may have betteroutcomes than surgery for plantar fasciitis. Comparativestudies are needed (surgery vs shock wave therapy)before absolute conclusions can be reached. However,few patients would agree to have the invasive treatmentof surgery if shock wave therapy is also available.

~ REFERENCES

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2. Rompe JD. Efficient use of extracorporeal shock waves intendonopathies. Eleclrol7ledica. 1997;65:20-25.

3. Haupt G. Use of extracorporeal shock waves in thetreatment of pseudarthrosis, tendinopathy and otherorthopedic diseases. JUral. 1997;158:4-11.

4. Vogel J, Rompe JD, Hopf C, et al. High-energy extra­corporeal shock-wave therapy (ESWT) in the treatment ofpseudartlu·osis.Z Orlhop Ihre Grenzgeb. 1997;135:145-149.

5. Heinrichs W, Witzsch U, Burger RA. Extracorporealshock-wave therapy (ESWT) for pseudoarthrosis. A new

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8. Loew M, Jurgowski W, Mau HC, et al. Treatment ofcalcifying tendinitis of rotator cuff by extracorporealshock waves: a preliminary report. J Shoulder ElbowSurg.1995;4:101-106.

9. FDA Sonocur basic summary of safety and effectiveness.www.fela.gov/cdrh/pelf/POI0039b.pelf.AccessedJuly 2002.

10. Wang CJ, Wang FS, Yang KD, et a!. Shock wave therapyinduces neovascularization at the tendon-bone junction.A study in rabbits. J Orlhop Res. 2003;21:984-989.

1L Wang CJ, Huang HY, Pai CH. Shock wave-enhancedneovascularization at the tendon-bone junction: an exper­iment in dogs. I Foot Ankle Surg. 2002;41:16-22.

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sonographic and histological study. J Bone Joinl SurgBr. 1998;80:546-552.

14. Ogden JA, Alvarez RG, Marlow M. Shockwave therapyfor chronic proximal plantar fasciitis: a meta-analysis.FOOLAnkle 1111; 2002;23:301-308.

15. Zhu F, Johnson JE, Hirose CB, et al. Chronic plantarfasciitis: acute ch~nges in the heel after extracorporealhigh-energy shock wave therapy-Observations at MRimaging. Radiology. 2005;234:206-210.

16. Hammer DS, Adam F, Kreutz A, et al. Ultrasonographicevaluation at 6-month follow-up of plantar fasciitis afterextracorporeal shock wave therapy. Arch Orthop Trauma

Surg.2005;125:6-9.

17. Buchbinder R, Ptasznik R, Gordon J, et al. Ultrasound­guided extracorporeal shock wave therapy for plantarfasciitis: a randomized controlled tria!. .lAMA. 2002;288:1364-1372.

18. Haake M, Buch M, Schoellner C, et a!. Extracorporealshock wave therapy for plantar fasciitis: randomisedcontrolled multicentre trial. BMJ. 2003;327:75.

19. Crawford F, Thomson C. Interventions for treatingplantar heel pain. Cochrane Database SYSI Rev. 2003:CD000416.

20. Regan W. Randomized prospective s·tudy of surgeryversus extra corporeal shock wave therapy for chroniclateral epicondylitis in worker's compensation boardpatients. Vancouver, 2004.

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.~ . S_1_1o.ckWave Therapy for Treatment of Foot and Ankle Conditions

21. Rompe lD, Schoellner C, Nafe B. Evaluation of low­energy extracorporeal shock-wave application for treat­ment of chronic plantar fasciitis. J Bone Joint Surg Am.2002;84-A:335-341.

22. Rompe JD, Hopf C, Nare B, et al. Low-energy extracOlporealshock wave therapy for painful heel: a prospective controlled

single-blirid study. Arch Ol1hop Trauma Surg. 1996;115:75-79.

23. Alvarez R. Preliminary results on the safety and efficacy

of the OssaTron for treatment of plantar fasciitis. FootAnkle Int. 2002;23:197-203.

24. Ogden lA, Alvarez R, Levitt R, et al. Shock wave therapyfor c11ro'1ic proximal plantar fasciitis. Clin Orthop RelatRes. 2001:47-59.

25. Rompe JD, Meurer A, Nafe B, et al. Repetitive low­energy shock wave application witho~'t local anesthesia is

more efficient than repetitive low-energy shock waveapplication with local anesthesi~ in the treatment ofchronic plantar fasciitis. J Orthop Res. 2005;23:931-941.

26. Rompe lD, Decking J, Schoellner C, et al. Shock waveapplication for chronic plantar fasciitis in running athletes.A prospective, randomized, placebo-controlled trial. Am JSports Med. 2003;31:268-275.

27. Hyer CF, Vancourt R, Block A. Evaluation of ultra­sound-guided extracorporeal shock waye therapy (ES\\ I)in the treatment of chronic plantar fasciitis. J Foot AnkleSurg. 2005;44:137-143.

28. Theodore OH, Buch M, Amendola A, et al. Extracorpo­

real shock wave therapy for the treatment of plantarfasciitis. Foot Ankle Int. 2004;25:290-297.

29. Ogden lA, Alvarez RO, Levitt RL, et al. Electrohy­

draulic high-energy shock-wave treatment of chronicplantar fasciitis. J Bone Joint Surg Am. 2004;86-A:2216-2228.

30. Speed CA, Nichols D, Wies l, et al. Extracorporeal shockwave therapy for plantar fasciitis. A double blindrandomised controlled trial. J Orthop Res. 2003;21:937-940.

31. Lee OP, Ogden lA, Cross OL. Effect of extracorporealshock waves on calcaneal bone spurs. Foot Ankle Int.2003;24:927-930.

32. Hammer DS, Adam F, Kreutz A, et al. Extracorporeal

shock wave therapy (ESWT) in patients with chronicproximal plantar fasciitis: a 2-year follow-up. Foot AnkleInt. 2003;24:823-828.

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