Ultrasound evaluation of plantar fasciitis

A constitutive model for the mechanical characterization of the plantar fascia

A constitutive model is proposed to describe the mechanical behavior of the plantar fascia. The mechanical characterization of the plantar fascia regards the role in the foot biomechanics and it is involved in many alterations of its functional behavior, both of mechanical and nonmechanical origin. The structural conformation of the plantar fascia in its middle part is characterized by the presence of collagen fibers reinforcing the tissue along a preferential orientation, which is that supporting the major loading. According to this anatomical evidence, the tissue is described by developing an isotropic fiber-reinforced constitutive model and since the elastic response of the fascia is here considered, the constitutive model is based on the theory of hyperelasticity. The model is consistent with a kinematical description of large strains mechanical behavior, which is typical of soft tissues. A fitting procedure of the constitutive model is implemented making use of experimental curves taken from the literature and referring to specimens of human plantar fascia. A satisfactory fitting of the tensile behavior of the plantar fascia has been performed, showing that the model correctly interprets the mechanical behavior of the tissue in the light of comparison to experimental data at disposal. A critical analysis of the model with respect to the problem of the identification of the constitutive parameters is proposed as the basis for planning a future experimental investigation of mechanical behavior of the plantar fascia.

Diagnostic imaging for chronic plantar heel pain: a systematic review and meta-analysis

Background

Chronic plantar heel pain (CPHP) is a generalised term used to describe a range of undifferentiated conditions affecting the plantar heel. Plantar fasciitis is reported as the most common cause and the terms are frequently used interchangeably in the literature. Diagnostic imaging has been used by many researchers and practitioners to investigate the involvement of specific anatomical structures in CPHP. These observations help to explain the underlying pathology of the disorder, and are of benefit in forming an accurate diagnosis and targeted treatment plan. The purpose of this systematic review was to investigate the diagnostic imaging features associated with CPHP, and evaluate study findings by meta-analysis where appropriate.

Methods

Bibliographic databases including Medline, Embase, CINAHL, SportDiscus and The Cochrane Library were searched electronically on March 25, 2009. Eligible articles were required to report imaging findings in participants with CPHP unrelated to inflammatory arthritis, and to compare these findings with a control group. Methodological quality was evaluated by use of the Quality Index as described by Downs and Black. Meta-analysis of study data was conducted where appropriate.

Results

Plantar fascia thickness as measured by ultrasonography was the most widely reported imaging feature. Meta-analysis revealed that the plantar fascia of CPHP participants was 2.16 mm thicker than control participants (95% CI = 1.60 to 2.71 mm, P < 0.001) and that CPHP participants were more likely to have plantar fascia thickness values greater than 4.0 mm (OR = 105.11, 95% CI = 3.09 to 3577.28, P = 0.01). CPHP participants were also more likely to show radiographic evidence of subcalcaneal spur than control participants (OR = 8.52, 95% CI = 4.08 to 17.77, P < 0.001).

Conclusion

This systematic review has identified 23 studies investigating the diagnostic imaging appearance of the plantar fascia and inferior calcaneum in people with CPHP. Analysis of these studies found that people with CPHP are likely to have a thickened plantar fascia with associated fluid collection, and that thickness values >4.0 mm are diagnostic of plantar fasciitis. Additionally, subcalcaneal spur formation is strongly associated with pain beneath the heel.

Ultrasound of enthesopathy in rheumatic diseases

Enthesopathy is the pathologic change of the insertion of tendons, ligaments and joint capsules on the bone. It is a cardinal feature of spondyloarthropathies (SpA), but it can occur in other rheumatic disease. Recent studies using magnetic resonance imaging (MRI) and ultrasonography (US) have demonstrated that enthesopathy can often be asymptomatic, in both the axial and peripheral skeleton. Therefore, a systematic US study of peripheral entheses could be useful in the diagnostic process of patients with rheumatic diseases, in particular SpA. Recently, power Doppler US (PDUS) has been proved to be useful for differentiating mechanical/degenerative and inflammatory enthesopathy and for monitoring the efficacy of therapy. This article reviews the main histopathologic aspects of enthesopathy and describes the normal US features of enthesis and the basic US features of enthesopathy, in its various stages. The usefulness of US and PDUS in the diagnosis and assessment of enthesopathy is discussed on the basis of the literature and our experience.

Ultrasonographic evaluation in plantar fasciitis

The heels of 23 patients who were diagnosed with unilateral/bilateral plantar fasciitis were evaluated via ultrasonography and compared with their asymptomatic feet and a control group of 23 people. Plantar fascial thickness, echogenity, and heel pad thickness were evaluated, and the results were statistically analyzed. For symptomatic feet, increased thickness of the fascia and reduced echogenity were constant ultrasonographic findings (mean, 4.79 mm for symptomatic feet; 2.17 mm for control group, P < .05). No significant difference was found between heel pads of the diseased and healthy feet (mean, 12.96 mm for symptomatic feet; 13.10 mm for control group; P > .05). Ultrasonography seems to be a valuable, noninvasive diagnostic tool for the evaluation of plantar fasciitis.

[Overuse syndromes of the foot]

Overuse syndromes due to lifestyle problems or sporting activities commonly lead to foot abnormalities. The tendons of the long flexor and extensor muscles are specifically prone to degeneration. The various disorders may be classified by a grading system that includes peritendinous inflammation, degenerative tendon disease, and ruptures. Bone marrow edema is another typical manifestation of overuse. It may be differentiated from inflammatory or traumatic forms of edema by its anatomic distribution. Systematic pattern recognition is based on the concept of musculotendinous and osseous kinetic chains.

Plantar fasciitis: are pain and fascial thickness associated with arch shape and loading?

BACKGROUND AND PURPOSE

Although plantar fascial thickening is a sonographic criterion for the diagnosis of plantar fasciitis, the effect of local loading and structural factors on fascial morphology are unknown. The purposes of this study were to compare sonographic measures of fascial thickness and radiographic measures of arch shape and regional loading of the foot during gait in individuals with and without unilateral plantar fasciitis and to investigate potential relationships between these loading and structural factors and the morphology of the plantar fascia in individuals with and without heel pain.

SUBJECTS

The participants were 10 subjects with unilateral plantar fasciitis and 10 matched asymptomatic controls.

METHODS

Heel pain on weight bearing was measured by a visual analog scale. Fascial thickness and static arch angle were determined from bilateral sagittal sonograms and weight-bearing lateral foot roentgenograms. Regional plantar loading was estimated from a pressure plate.

RESULTS

On average, the plantar fascia of the symptomatic limb was thicker than the plantar fascia of the asymptomatic limb (6.1+/-1.4 mm versus 4.2+/-0.5 mm), which, in turn, was thicker than the fascia of the matched control limbs (3.4+/-0.5 mm and 3.5+/-0.6 mm). Pain was correlated with fascial thickness, arch angle, and midfoot loading in the symptomatic foot. Fascial thickness, in turn, was positively correlated with arch angle in symptomatic and asymptomatic feet and with peak regional loading of the midfoot in the symptomatic limb.

DISCUSSION AND CONCLUSION

The findings indicate that fascial thickness and pain in plantar fasciitis are associated with the regional loading and static shape of the arch.

Thinner plantar fascia predicts decreased pain after extracorporeal shock wave therapy

Increased plantar fascia thickness is common with chronic plantar fasciitis, and reduction of the thickness after extracorporeal shock wave therapy or steroid injection has been reported. We hypothesized a decrease of plantar fascia thickness was associated with pain reduction after extracorporeal shock wave therapy. Fifty-three eligible patients with 78 symptomatic feet were randomly treated with piezoelectric-type extracorporeal shock wave therapy of two intensity levels (0.12 and 0.56 mJ/mm2). Two thousand shock waves for three consecutive sessions were applied at weekly intervals. A visual analog scale for pain, the Foot Function Index, the Short Form-36 Health Survey, and ultrasonographic measurement of plantar fascia thickness were evaluated at baseline and 3 and 6 months after treatment. We analyzed the association between pain level and plantar fascia thickness with generalized estimating equation analysis and adjusted for demographic and treatment-related variables. Patients with thinner plantar fascia experienced less pain after treatment; high-intensity treatment and regular exercise were associated with lower pain level. The overall success rates were 63% and 60% at the 3- and 6-month followups. High- and low-intensity treatments were associated with similar improvements in pain and function. Receiving high-intensity treatment, although associated with less pain at followup, did not provide a higher success rate.

Effect of gender, age and anthropometric variables on plantar fascia thickness at different locations in asymptomatic subjects

PURPOSE

The study was aimed to investigate plantar fascia thickness at different locations in healthy asymptomatic subjects and its relationship to the following variables: weight, height, sex and age.

MATERIAL AND METHODS

The study evaluates 96 feet of healthy asymptomatic volunteers. The plantar fascia thickness was measured at four different locations: 1cm proximal to the insertion of the plantar fascia, at the insertion of the plantar fascia on the calcaneus and separate out 1 cm + 2 cm distal to the insertion. A 10 MHz linear-array transducer was used.

RESULTS

There were statistically significant differences in plantar fascia thickness at the four different locations (p<0.001) although no differences in PF thickness were found between the two distal from insertion locations (1 and 2 cm). Multiple regression analysis showed sex as independent predictor of plantar fascia thickness at 1cm proximal to the insertion. At origin and 1cm distal to insertion weight was an independent predictor of plantar fascia thickness.

CONCLUSIONS

There are differences of thickness at different locations of plantar fascia measured by ultrasonography. Thickness at 1cm proximal to the insertion is influenced by sex and thickness at origin and at 1cm distal to the insertion has a direct relationship with body weight. This could be attributed to the overloading effect that weight has on plantar fascia in healthy symptomatic subjects at these two locations. Height and age did not seem to influence as independent variables in plantar fascia thickness among non-painful subjects.

Plantar fasciitis treated with local steroid injection: comparison between sonographic and palpation guidance

PURPOSE

To compare the effectiveness of sonographically guided and palpation-guided steroid injection for the treatment of proximal plantar fasciitis.

PATIENTS AND METHODS

Twenty-five consecutive patients with unilateral proximal plantar fasciitis were recruited and randomly divided into a sonographically guided group (n = 12) and palpation-guided group (n = 13). Proximal plantar fascia was assessed with a 5- to 12-MHz linear-array transducer. Pain intensity was quantified using a "tenderness threshold" (TT) and a visual analog scale (VAS). Injection of 7 mg (1 ml) of betamethasone and 0.5 ml of 1% lidocaine into the inflamed proximal plantar fascia was performed under the guidance of sonography or palpation. Patients were evaluated clinically and sonographically before injection and at 2 weeks, 2 months, and 1 year after injection. VAS- and TT-measured pain intensity, thickness, and echogenicity of the proximal plantar fascia, as well as the recurrence of heel pain, were assessed.

RESULTS

Both VAS- and TT-measured levels of pain improved significantly after steroid injection in both groups (p < 0.001). Also, the thickness decreased significantly after injection (p < 0.01 in the palpation-guided group; p < 0.001 in the sonographically guided group). The number of patients with hypoechogenicity at the proximal plantar fascia decreased after steroid injection in both groups (p < 0.01 for both groups). The recurrence rate of plantar fasciitis in patients of the palpation-guided group (6/13) was significantly higher than that of the sonographically guided group (1/12) (p < 0.05).

CONCLUSIONS

Steroid injection can be an effective way to treat plantar fasciitis, and injection under sonographic guidance is associated with lower recurrence of heel pain.

Clinical utility of sonography in diagnosing plantar fasciitis

OBJECTIVE

The purpose of this study was to investigate the efficacy of sonography in the detection of plantar fasciitis (PF) compared with magnetic resonance imaging (MRI) findings in subjects with inferior heel pain.

METHODS

Seventy-seven patients with unilateral (n = 9) and bilateral (n = 68) heel pain were studied. Seventy-seven age- and sex-matched asymptomatic subjects served as a control group. Magnetic resonance imaging was used to establish a diagnosis of PF with sagittal T1-weighted, T2-weighted, and short tau inversion recovery sequences. The sonographic appearances of PF were compared with MRI findings. Plantar fascia and heel pad thickness were also measured on both imaging modalities.

RESULTS

Compared with MRI, sonography showed 80% sensitivity and 88.5% specificity in assessing PF. A strong correlation was found between plantar fascia and fat pad thickness measurements done by sonography (P < .001; r = 0.854) and MRI (P < .001; r = 0.798). Compared with the asymptomatic volunteers, patients with PF had significant increases in plantar fascia and heel pad thicknesses, weight, and body mass index (P = .0001). Heel pad thickness was also significantly increased with pain duration (P = .021).

CONCLUSIONS

Although MRI is the modality of choice in the morphologic assessment of different plantar fascia lesions, sonography can also serve as an effective tool and may substitute MRI in the diagnosis of PF.

Long-term ultrasonographic follow-up of plantar fasciitis patients treated with steroid injection

OBJECTIVE

To evaluate the long-term efficacy of steroid injection for plantar fasciitis using clinical parameters and high-resolution ultrasonography.

MATERIAL AND METHODS

Thirty patients (27 female and three male) with plantar fasciitis and 30 healthy controls matched by age, gender and body mass index (BMI), were enrolled in this study. Seventeen of the patients had bilateral and 13 had unilateral (six right, seven left) plantar fasciitis. Palpation-guided steroid injection was applied to the 47 heels of 30 plantar fasciitis patients. Ultrasound examination and pain intensity with visual analog scale (VAS) were assessed three times in each plantar fasciitis patients; before injection and at 1 and 6 months after steroid injection. Ultrasonography was performed to the controls at initial assessment.

RESULTS

The plantar fascia was remarkably thicker in the plantar fasciitis group than in controls (P < 0.001). The thickness of the plantar fascia and mean VAS values in the plantar fasciitis group decreased significantly 1 month after steroid injection (P < 0.001, P < 0.001, respectively) and a further decrease was noted 6 months postinjection (P < 0.001, P < 0.001, respectively). Strong correlation was found between the changes of plantar fascia thickness and VAS values 1 month after (P < 0.001, r: 0.61) and 6 months after (P < 0.001, r: 0.49) steroid injection. The incidence of hypoechoic fascia was 73% in the plantar fasciitis group before steroid injection. It decreased significantly at 1 and 6 months postinjection (33% and 7%, respectively, P < 0.001). Gross fascia disruption or other side effects were not observed after steroid injection.

CONCLUSION

Steroid injection could be used in plantar fasciitis treatment for its positive long-term effects.

Ultrasonographic evaluation at 6-month follow-up of plantar fasciitis after extracorporeal shock wave therapy

INTRODUCTION

The aim of this study was to investigate the effect of extracorporeal shock wave therapy (ESWT) on the ultrasonographic appearance of chronically painful, proximal plantar fasciitis.

MATERIALS AND METHODS

Twenty-two patients with a unilateral proximal plantar fasciitis were prospectively enrolled after unsuccessful conservative treatment lasting 6 months. The contralateral plantar fascia was used as the control. ESWT (3x3000 shock waves/session of 0.2 mJ/mm2) was performed at weekly intervals. The thickness of the plantar fascia was measured ultrasonographically about 2 cm distal of the medial calcaneal tuberosity. Pain estimation on a visual analogue scale (VAS) and the comfortable walking time were recorded. No local anaesthesia was applied. Follow-up was done at 6, 12 and 24 weeks.

RESULTS

Before ESWT, the plantar fasciitis side was ultrasonographically significantly thicker than the control side (p<0.05), whereas 6 months after ESWT, the thickness of the fascia was no longer significantly different. The decrease in thickness of the plantar fasciitis side was significant (p<0.05). Pain during activities of daily living decreased by 79% according to the VAS, and the comfortable walking time increased, both significantly (p<0.01). In patients with little pain (VAS<30), the thickness of the plantar fasciitis side was significantly less (p<0.01) compared with patients who still suffered more pain (VAS>30).

CONCLUSION

After ESWT, the thickness of the plantar fascia in patients with plantar fasciitis decreased, pain and walking time improved (all significantly).

Evidence-Based Soft Tissue Rheumatology. V

Present evidence indicates that the main cause of plantar talalgia (PT) is a noninflammatory derangement at the proximal insertion of the plantar fascia. In athletes, predisposing ankle and rear-foot biomechanical abnormalities have been identified; in nonathletes, risk factors for the condition remain controversial. PT diagnosis is largely clinical, the key findings being pain and tenderness on the plantar aspect of the rear foot. Ultrasonography is a reliable confirmatory study in doubtful cases. Therapies in PT include nonsteroidal anti-inflammatory drugs, orthotic devices, night ankle dorsiflexion splints, physiotherapy, local glucocorticoid, and extracorporeal shockwave therapy. In recalcitrant cases, surgery may be offered. Of these therapies, only local glucocorticoid, as delivered by injection or iontophoresis, has shown short-term efficacy in controlled trials. The efficacy of ankle dorsiflexion splints and extracorporeal shockwave therapy is still controversial. Thus, important knowledge gaps remain on etiology, diagnosis, and treatment of PT.

Ultrasonographic appearance of the plantar fasciitis

PURPOSE

To study high frequency sonographic in the examination of plantar fasciitis (PF), which is a common cause of heel pain.

MATERIALS AND METHODS

Our study was done with 25 PF (21 unilateral, 4 bilateral) and 15 control cases of similar age, weight and gender. In this study, the plantar fascial thickness (mainly), fascial echogenity and biconvexity were examined using 7.5 MHz linear phase array transducer. Perifascial fluid collection, fascial rupture and fascial calcification that are rarely seen were also examined.

RESULTS

The fascial thickness ranges for the PF cases: for the symptomatic heels: 3.9-9.1 mm (mean: 4.75 +/- 1.52 mm), for the asymptomatic heels: 2.0-5.9 mm (mean: 3.37 +/- 1.0 mm) and for the control group: 2.1-4.7 mm (3.62 +/- 0.68 mm). The results were significantly different in Group I for symptomatic heels and the control group statistically for PF (P < .05). The echogenity of plantar fascia and biconvexity of plantar fascia were the major criteria for symptomatic heels. In three heels (10%), perifascial fluid was diagnosed, in three heels (10%) fascial calcification, in one heel (3%) partial fascial rupture. Subcalcaneal spur was encountered sonographically in both cases of Groups I and II.

CONCLUSION

Ultrasonography (US) is the first step for PF, because of its easy and quick performance, availability and high sensitivity of diagnosis, low-cost and free radiation.