plantar fasciitis is one of the most common causes of foot pain in adults , with the peak incidence occurs between ages 40 and 60 years in the general population . in up to a third of the cases it may be bilateral , and
heel spurs often coexist , but whether they have a causal role in the etiology of the disease is still unknown .
suggested risk factors include those conditions that increase the pressure at the plantar surface such as obesity , prolonged standing , flat feet , and reduced ankle dorsiflexion .
the high incidence in runners suggests that , at least in this population , plantar fasciitis might be due to an injury by repetitive microtrauma .
the diagnosis of plantar fasciitis is clinical and local point tenderness is the hallmark for diagnosis , while laboratory testing is not helpful nor necessary for the diagnosis .
however , radiography is required to rule out other disorders , especially calcaneal stress fractures .
ultrasonography of the foot is also useful in diagnosis and treatment follow - ups with indicating plantar fascial thickening , hypoechogenicity at the insertion upon the calcaneus , and features of edema including blurring of the boundary between the fascia and surrounding tissues and decreased echogenicity.[810 ] diagnostic accuracy of ultrasonography for the diagnosis of plantar fasciitis is acceptable ( sensitivity 80% and specificity 88.5% ) , and doppler ultrasound can improve the accuracy and provide additional information on local hyperemia as well .
the treatment of plantar fasciitis is primarily conservative , initially with rest and icing to give pain relief .
non - steroidal anti - inflammatory drugs ( nsaids ) , local injection of steroids , and electrotherapy and physiotherapy with stretching exercises are also used . in about 10% of the cases who do not respond to such treatments , surgical intervention is suggested .
extracorporeal shock wave therapy ( eswt ) is a noninvasive procedure used in rehabilitation therapy that is recently being applied in the treatment of tendinopathies and also plantar fasciitis.[1420 ] in eswt , shock waves are generated by means of electrohydraulic , piezoelectric , and electromagnetic methods .
the transmitted waves may have effects on physiology of pain receptor , and also , through microtrauma , they may initiate healing processes by the release of molecular agents and growth factors leading to neovascularization .
despite increasing use of eswt in the treatment of plantar fasciitis , few well - controlled trials have been conducted to approve its efficacy with conflicting results .
therefore , we conducted a randomized , placebo - controlled trial to evaluate the efficacy of eswt in the management of plantar fasciitis .
the outcome was documented by the ultrasonographic appearance of the aponeurosis , as well as by subjective pain scores .
this randomized , placebo - controlled trial was conducted from jun 2010 to jul 2011 on adult patients with a clinical diagnosis of plantar fasciitis referred to the outpatient clinics of alzahra university hospital , isfahan ( iran ) .
patients with plantar heel pain for at least three months and point tenderness at or near the medial calcaneal insertion of the plantar fascia , who had no satisfactory response to common treatments such as nsaids and physiotherapy were included .
patients with diabetes , additional foot or ankle pathology ( including instability , arthritis , generalized polyarthritis , diffuse heel pad tenderness ) , local dermatological problems , neurological abnormalities , history of recent trauma or foot surgery , connective tissue or infectious diseases , malignancy , or vasculitis and pregnant patients or those who received anticoagulant therapy in the preceding six months were not included . considering type i error ( alpha ) = 0.05 and
study power = 80% , with minimum expected difference of 1 score in 11-point scale for pain assessment , the sample size was calculated as at least 20 patients in each group .
the study protocol was approved by the ethics committee of isfahan university of medical sciences and informed consent was obtained from all patients .
patients were randomly assigned ( by a random table list ) to receive eswt ( n = 20 ) or identical sham therapy as the placebo ( n = 20 ) by weekly interval for three consecutive weeks .
we used the site of maximum local tenderness as the target area for shock waves with duolith sd1 shock wave machine .
patient in the intervention group received 2000 focused shock waves and 2000 radial pulses in three sessions ( 4000 shock waves / session of 0.2 mj / mm ) at weekly intervals .
eswt dose and treatment schedule were based on the previous studies . for the placebo group
sham treatment was done where standard contact of radial and focus probe with the skin was provided .
the machine makes a noise with every shock wave delivered and , in order to enhance the sham design , minimal energy pulses ( 0.04 mj / mm ) were generated .
ultrasound was performed by the same radiologist , using a 10 mhz linear array transducer .
both heels of the participants were scanned in two - dimensional ( 2d ) real - time b mode .
sagital imaging of the plantar fascia was performed with the transducer aligned along the longitudinal axis of the aponeurosis .
quantitative evaluation of plantar fasciitis was achieved by measurement of its thickness about 2 cm distal of the medial calcaneal tuberosity .
in addition , qualitative assessment including echogenic appearance of plantar fascia and its fibrillary pattern was done .
for subjective pain assessment , all subjects completed a numerical rating scale ( nrs ) for foot pain ( from 0 = no pain to 10 = the most severe pain ) during the daily activity .
all assessments ( pain and ultrasonographic evaluation ) were repeated three months after completion of the therapy . along this time , conservative managements including stretching exercise , using nsaids , and heel pad were considered in both groups .
a paired samples t - test was used to ascertain significant changes in both plantar fascia thickness and subjective sub - calcaneal pain over the experimental period , and an independent t - test was used for detecting any significant differences in these two parameters between the two groups .
a result was considered to be statistically significant if the observed significance level ( p value ) was < 0.05 .
this randomized , placebo - controlled trial was conducted from jun 2010 to jul 2011 on adult patients with a clinical diagnosis of plantar fasciitis referred to the outpatient clinics of alzahra university hospital , isfahan ( iran ) .
patients with plantar heel pain for at least three months and point tenderness at or near the medial calcaneal insertion of the plantar fascia , who had no satisfactory response to common treatments such as nsaids and physiotherapy were included .
patients with diabetes , additional foot or ankle pathology ( including instability , arthritis , generalized polyarthritis , diffuse heel pad tenderness ) , local dermatological problems , neurological abnormalities , history of recent trauma or foot surgery , connective tissue or infectious diseases , malignancy , or vasculitis and pregnant patients or those who received anticoagulant therapy in the preceding six months were not included . considering type i error ( alpha ) = 0.05 and
study power = 80% , with minimum expected difference of 1 score in 11-point scale for pain assessment , the sample size was calculated as at least 20 patients in each group .
the study protocol was approved by the ethics committee of isfahan university of medical sciences and informed consent was obtained from all patients .
patients were randomly assigned ( by a random table list ) to receive eswt ( n = 20 ) or identical sham therapy as the placebo ( n = 20 ) by weekly interval for three consecutive weeks .
we used the site of maximum local tenderness as the target area for shock waves with duolith sd1 shock wave machine .
patient in the intervention group received 2000 focused shock waves and 2000 radial pulses in three sessions ( 4000 shock waves / session of 0.2 mj / mm ) at weekly intervals .
eswt dose and treatment schedule were based on the previous studies . for the placebo group
sham treatment was done where standard contact of radial and focus probe with the skin was provided .
the machine makes a noise with every shock wave delivered and , in order to enhance the sham design , minimal energy pulses ( 0.04 mj / mm ) were generated .
ultrasound was performed by the same radiologist , using a 10 mhz linear array transducer . both heels of the participants
sagital imaging of the plantar fascia was performed with the transducer aligned along the longitudinal axis of the aponeurosis .
quantitative evaluation of plantar fasciitis was achieved by measurement of its thickness about 2 cm distal of the medial calcaneal tuberosity .
in addition , qualitative assessment including echogenic appearance of plantar fascia and its fibrillary pattern was done . for subjective pain assessment ,
all subjects completed a numerical rating scale ( nrs ) for foot pain ( from 0 = no pain to 10 = the most severe pain ) during the daily activity .
all assessments ( pain and ultrasonographic evaluation ) were repeated three months after completion of the therapy . along this time , conservative managements including stretching exercise , using nsaids , and heel pad were considered in both groups .
data were analyzed with spss software for windows , version 16.0 ( spss inc . , chicago il .
a paired samples t - test was used to ascertain significant changes in both plantar fascia thickness and subjective sub - calcaneal pain over the experimental period , and an independent t - test was used for detecting any significant differences in these two parameters between the two groups .
a result was considered to be statistically significant if the observed significance level ( p value ) was < 0.05 .
during the study period , 40 patients with plantar fasciitis were enrolled and completed the study [ figure 1 ] .
participants flow diagram demographic characteristics of the two groups data regarding plantar fascia thickness and pain scores are presented in table 2 . in two patients who had severe pain ,
initially there were no significant differences between the mean plantar fascia thickness of the two groups ( p = 0.95 ) .
after treatment , the mean plantar fascia thickness was significantly decreased in the eswt group ( p < 0.001 ) , while it was slightly increased in the placebo group ( p = 0.03 ) , figure 2 .
comparison of pain scores and plantar fascia thickness before and after the study within and between the two groups post - treatment plantar fascia thickness in the placebo ( a ) and eswt ( b ) groups regarding the nrs pain scores , no significant difference were observed between the pain scores of the two groups at baseline ( p = 0.59 ) , but after three months follow - up , pain scores was significantly lower in the eswt group than in the placebo group ( p = 0.04 ) .
both groups showed significant pain improvement over the course of the study , although reduction of nrs score in the intervention group was significantly greater than in the placebo group ( -4.2  2.9 vs. -2.7  1.8 , p = 0.049 ) . to find factors associated with better response to eswt , we splatted the groups and analyzed data from the eswt group .
results showed a significant inverse correlation between plantar fascia thickness change and bmi ( r = -0.597 , p = 0.005 ) .
the association between change in pain score and change in plantar fascia thickness was not significant ( r = 0.365 , p = 0.114 ) .
there are various options for the treatment of plantar fasciitis , but a lot of them are not satisfactory effective and some of them are associated with risks . for example , glucocorticoid injections can provide temporary pain relief ; however , repeated injections may cause atrophy of the heel pad , and even plantar fascia rupture . surgical interventions , on the other hand , can alter the biomechanics of the foot and prolonged the healing process . accordingly
, eswt has been proposed as a therapeutic option for plantar fasciitis , as well as some other musculoskeletal complaints . during the past decade
, eswt has become increasingly used worldwide , and based on some well - controlled trials ; recently it was approved by the fda for treatment of plantar fasciitis in the usa .
a placebo - controlled multicentre trial of eswt by haake and colleagues in subjects with chronic plantar fasciitis indicated superior improvement in the active treatment than the placebo group . in another randomized trial , rompe et al .
, assigned patients to stretching or low energy shock wave therapy and at the 2-month assessment authors found a greater mean change in foot function index cumulative score and a higher patient satisfaction for those who were treated with stretching .
these results were stable at the 4-month follow - up , but no difference found between the groups at the 15-month follow - up , though use of nsaids was more common among patients treated with shock wave therapy . in another placebo - controlled trial by speed et al .
, on adults with plantar fasciitis , no beneficial effects were observed for shock wave therapy ( 0.12 mj / mm ) versus the sham placebo over a 6-month period .
these results , however , might be due to the moderate dose eswt effects comparable with placebo effects . the differences between various studies in the efficacy of eswt in plantar fasciitis may be related to a number of factors including differences in study populations , heterogeneity of treatment parameters such as shock wave intensity , geometry of the shock wave focus , focal energy , different placebos and different machine design .
an emphasis is placed upon the use of a feasible regime with minimal side effects .
although the technique is widely reported to be safe , there is a potential for hemorrhage and local soft tissue damage through cavitations .
for this reason , a moderate radial and focus dose regime using an electromagnetic generator was chosen in our study , which avoided the need for administration of local anesthetic or significant post- treatment rest .
significant adverse effects were not noted in our study , in agreement with the experience of others and the results indicated that moderate dose of eswt has significant beneficial effects over placebo .
although , pain intensity in the sham group was significantly reduced over the experimental period , ultrasonograghy showed slightly increase in plantar fascia thickness .
these results indicate that other factors can lead to false impressions of a placebo effect , such as spontaneous improvement and fluctuation of symptoms .
in summary , while ultrasound imaging is able to depict the morphologic changes related to plantar fasciitis , eswt can contribute to healing and pain reduction in plantar fasciitis .
further studies are required to find the mechanisms of action of eswt in the treatment of plantar fasciitis .
 background and aim : results of previous studies have been conflicting on the efficacy of extracorporeal shock wave therapy ( eswt ) in the treatment of plantar fasciitis . 
 we evaluated the effects of eswt on plantar fasciitis in terms of ultrasonographic and subjective evaluations.materials and methods : in this randomized placebo - controlled trial , patients with plantar fasciitis were assigned to receive eswt ( 4000 shock waves / session of 0.2 mj / mm2 ) in 3 sessions at weekly intervals ) or sham therapy ( n = 20 in each group ) . 
 outcomes were documented by the ultrasonographic appearance of the aponeurosis and by patients pain scores , performed at baseline and 12 weeks after completion of the therapy.results:the two groups were similar in baseline characteristics . over the study period , 
 plantar fascia thickness significantly reduced in the eswt group ( 4.1  1.3 to 3.6  1.2 mm , p < 0.001 ) , but slightly increased in the sham group ( 4.1  0.8 to 4.5  0.9 mm , p = 0.03 ) . 
 both groups showed significant pain improvement over the course of the study ( p < 0.001 ) , though pain scores were significantly more reduced in the eswt than the sham group ( -4.2  2.9 vs. -2.7  1.8 , p = 0.049).conclusions : extracorporeal shock wave therapy contributes to healing and pain reduction in plantar fasciitis and ultrasound imaging is able to depict the morphologic changes related to plantar fasciitis as a result of this therapy . 
INTRODUCTION
MATERIALS AND METHODS
Patients and settings
Intervention
Assessments
Statistical analysis
RESULTS
DISCUSSION
CONCLUSIONS