A systematic review of treatments for the painful heel

D. Atkins, F. Crawford1, J. Edwards and M. Lambert1

Department of Rheumatology, University College, London and
1 Department of Health Sciences and Clinical Evaluation, Alcuin College, University of York, Heslington, York YO10 5DD, UK

Correspondence to: F. Crawford.


    Abstract
 Top
 Abstract
 Introduction
 Methods
 Results
 Conclusion
 References
 
Objective. To establish the efficacy for treatments of pain on the plantar aspect of the heel.

Methods. Systematic review of the published and unpublished literature. Electronic search of Medline, BIDS and the Cochrane database of clinical trials. An assessment of the quality of the reporting was made of studies included in the review. Main outcome measure: patients' pain scores. Study selection: randomized controlled trials, published or unpublished, that evaluated treatments used for plantar heel pain. Foreign language papers were excluded.

Results. Eleven randomized controlled trials were included in the review. These evaluated some of the most frequently described treatments (steroid injections and orthoses) and some experimental therapies (extracorporeal shock wave therapy and directed electrons). The methodological assessment scores of the published trials were low; small sample sizes and failure to conceal the treatment allocation from study participants prevents more definitive statements about the efficacy of treatments. In 10 of the included trials, patients in both the intervention and control arms reported improved pain scores at the final outcome measure.

Conclusions. Although much has been written about the treatment of plantar heel pain, the few randomized controlled trials involve small populations of patients and do not provide robust scientific evidence of treatment efficacy.

KEY WORDS: Heel, Pain, Treatment, Efficacy, Systematic review.


    Introduction
 Top
 Abstract
 Introduction
 Methods
 Results
 Conclusion
 References
 
The painful heel is frequently seen in general practice, rheumatology and podiatry clinics, in patients seeking a quick and effective cure. It has been estimated to affect 10% of runners and present in the general population at the same rate [1]. A variety of names are used to describe heel pain: plantar fasciitis, jogger's heel, tennis heel, Policeman's heel [2] and gonorrhoeal heel [3]. The last of these reflects the incorrectly presumed association between venereal disease and heel pain that prevailed in the early 20th century. Although much has been written about this condition, little is known of the underlying disease process or its natural evolution [4]. Since heel pain is recognized both as a feature of (predominantly seronegative) inflammatory rheumatic disease and as an isolated symptom in the normal population, it is likely that it can have either an inflammatory or mechanical origin. The degree of disability it causes can vary. Some patients experience a dull ache, while others report pain so great that it imposes a sedentary lifestyle. Patients often seek treatment only after experiencing heel pain for several weeks and some authors believe that the duration of pain affects the prognosis [4]. The most commonly described therapies are corticosteroid injections, non-steroidal anti-inflammatory drugs (NSAIDs), heel pads, orthoses, exercises, night splints and, in intractable cases, surgical procedures (Tables 1 and 2GoGo). However, much of the literature about treatment is based on authors' experiences and beliefs rather than unbiased evaluations. This article reports what we believe to be the first systematic review of the efficacy of commonly used treatments for the painful heel.


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TABLE 1.  Conservative treatments described
 

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TABLE 2.  Surgical treatments described
 

    Methods
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 Abstract
 Introduction
 Methods
 Results
 Conclusion
 References
 
Trials were included in the review if they were randomized or quasi-randomized (methods of allocating participants to treatments which are not strictly random, e.g. date of birth, hospital record number or alternation). Case studies, retrospective studies, descriptive articles or studies with historic controls only were excluded from the review, but all were tabulated to assess the available literature. Foreign language papers were excluded.

Medline, from 1966 to June 1998, was searched using a generic search strategy described by Dickersin et al. [5] combined with 10 condition-specific items [6]. Additional searching was undertaken using the BIDS database, from hand searching The Chiropodist, The Journal of British Podiatric Medicine, The Foot and the reference lists of all located reports. Contact was made with university podiatry departments to request unpublished theses on heel pain held in their libraries.

A methodological assessment tool based on the 21 items within the Consolidated Standards of Reporting Trials (CONSORT) statement was developed and used to evaluate the design, conduct, analysis and generalizability of trials, and to assess their internal validity [7]. Two reviewers (FC and DA) independently applied these criteria to each reported trial (which had been blinded to obscure the authors) and scored them out of 21 according to the number of methodological assessment items reported. Particular attention was paid to issues of trial design and implementation judged most likely to compromise the main study findings, specifically, the blinding of health professionals and patients to treatment allocation [8]. The objectivity (blinding) of outcome measurements and loss to follow-up were also assessed (Table 4Go). The identified trials were scrutinized for outcome measures of patients' heel pain. Disagreements were resolved by discussion.


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TABLE 4.  Quality assessment of studies
 
Where summary statistics were either not reported or incompletely reported, the authors were contacted for the additional information. Where homogeneity of interventions existed, it was intended to provide a pooled relative risk for each subgroup of trial interventions, using a fixed-effects model. Where there was evidence of heterogeneity of interventions, it was intended to use a random-effects model [9].


    Results
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 Abstract
 Introduction
 Methods
 Results
 Conclusion
 References
 
The Medline search identified 47 published reports of treatments for plantar heel pain between 1966 and June 1998. Nine were reports of randomized controlled trials [1018]. Direct contact with schools of podiatry resulted in the identification of two randomized controlled trials which were unpublished dissertations [19, 20]. Two trials were located by direct contact with investigators [21, 22]. Direct contact with the Cochrane Collaboration Musculoskeletal Subgroup resulted in the location of one trial [23].

The search of the BIDS database, our hand search and the reference lists of reports identified a further 115 reports of treatments for plantar heel pain, none of which were randomized controlled trials. A total of 153 reports were excluded from the review (Table 3Go). The conservative and surgical treatments described in both the included and excluded reports appear listed in order of frequency (Tables 1 and 2GoGo).


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TABLE 3.  Taxonomy of excluded reports
 
Fourteen randomized controlled trials were considered for inclusion in this review and three were excluded. Batt et al. [11] evaluated the effectiveness of tension night splints, but assessed group outcomes at different times after treatment. Fauno et al. [15] evaluated the use of heel pads in the prevention rather than the treatment of plantar heel pain. Noble [23] undertook a study of fenbufen in the treatment of overuse injuries in runners, but presented combined data for 17 conditions, of which heel pain was one.

Details of the eleven trials included in the review grouped according to intervention
We found no information in these articles on the natural course of the disease and the diagnostic features of heel pain varied enormously. Table 4Go shows the methodological scores and sources of bias in the trials, whilst Table 5Go gives details of the trials' participants and outcomes.


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TABLE 5.  Details of study participants and outcomes
 
Steroid injections and pads
Steroid injections vs viscoheel pads (Black et al. [19]).
Patients were randomized to receive either a viscoheel heel pad or a heel injection of triamcinolone (Lederspan) 20 mg with 2% lignocaine. The injection group were advised to advised to rest for 48 h after the procedure.

Steroid injection vs saline injection (Blockey [12]).
Painful heels were either injected with 25 mg hydrocortisone acetate or saline injection. All patients were also given a sponge heel pad.

Steroid injections alone vs pads alone vs steroid injections and pads (Kriss [21]).
In this three-arm trial, patients received either an anti-pronatory insole or a steroid injection of triamcinolone hexacetonide (Lederspan) 20 mg mixed with 2% lignocaine or both.

Physical therapies
Low-intensity laser therapy (Basford et al. [10]).
Affected feet were irradiated either with a 30 mW continuous-wave 0.83 µm GaA1As IR diode laser or a disabled laser probe. Treatment consisted of three periods of 33 s `sweeps' at both the origin of the plantar fascia and the medial border.

True ultrasound vs placebo ultrasound (Crawford and Snaith [14]).
Episodes of heel pain were allocated to either true ultrasound at a dosage of 0.5 W/cm2 , pulsed 1:4, 3 Mz for 8 min, or placebo ultrasound when only the timer was set. All patients received eight treatments in 4 weeks.

Ionophoresis with dexamethasone vs ionophoresis with saline (Gudeman et al. [16]).
Group 1 patients were treated with placebo ionophoresis (buffered saline) while group 2 patients received ionophoresis with dexamethosone. All patients also received six sessions of ice and stretching programmes over a 2–3 week period.

Bioelectron MKII (Nolan [20]).
This experimental device produced a beam of electrons, delivered onto the surface of the skin via a probe. The manufacturers claimed that this reduced tissue acidity and restored the inflamed area to normal pH. Patients were randomized to receive either a functioning or a disabled device. After instruction, patients used the device at home, administering treatment for 5 min three times daily over 21 days.

Extracorporeal shock wave therapy (ESWT) vs placebo (Rompe et al. [18]).
ESWT was applied using an experimental device, the Siemens Osteostar. The device made contact with feet in the treatment group only, feet in the placebo group had the device held at a 1 cm distance. In the treatment group, the energy density was 0.06 mJ/mm2 three times in weekly intervals.

Extracorporeal shock wave therapy 1000 impulses vs 10 impulses (Rompe et al. [22]).
ESWT was applied using an experimental device, the Siemens Osteostar. Patients in group 1 received 1000 impulses three times at weekly intervals, patients in group 2 received 10 impulses in the same time period. This second study of ESWT by Rompe et al. involved the largest number of patients in any of the trials in this review.

Insoles and night splints
PPT insoles vs PPT insoles with magnetic foil (Caselli et al. [13]).
Patients in the treatment group wore PPT Rx (type of mass-produced insole) firm moulded insoles containing a Nikken magnetic foil placed in the heel. Control group patients wore the same insole without the magnetic foil. All patients wore the insole for 4 weeks, with no co-interventions.

Night splints (Powell et al. [17]).
In their allocated intervention month, each patient received a night splint made of polypropylene with the ankle placed in 5° of dorsiflexion. Foam was used distally on the splint to give 30° dorsiflexion at the MTP joints.

Summary statistics (mean pain scores with standard deviations) were available for only five reports [14, 20, 21, 23]. The outcomes for all trial participants are reported in Table 6Go. Seven studies reported excluding individuals with seropositive and seronegative conditions, [1214, 1719, 22], and a further three excluded patients taking either steroids or NSAIDs, or both [10, 20, 21].


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TABLE 6.  Summary of interventions, outcomes and quality of reporting of included studies
 
Evaluations of lasers [10], ultrasound [14], steroid injections vs heel pads [19], steroid injections vs saline [12], Bioelectron MKII [18], and insoles with and without magnetic foil [13] failed to detect differences between the treatment and placebo groups (Table 6Go). All six trials had small sample sizes (Table 5Go) and this may have resulted in either beneficial or detrimental treatment effects being undetected.

In the five trials that did find statistically significant improvements in pain, the evaluation of ionophoresis and dexamethosone compared with ionophoresis and saline [16] showed an improvement in the outcomes of the dexamethosone group at 1 month only. At outcomes taken thereafter, no differences were detected.

In the trial by Kriss [21], the results showed that patients who received steroid injections alone had the greatest improvement in pain levels. The main threats to the internal validity of this trial was the patients', health professionals' and evaluators' knowledge of the treatment allocation (Table 4Go).

In both trials of ESWT [18, 22], the health professionals were aware of the treatment allocation. The authors suggest that the painful nature of ESWT therapy meant it was unlikely that patients were unaware of the treatment allocation in the larger study, and in the smaller study the equipment did not make contact with the feet of patients in the placebo group.

Although the cross-over trial of night splints [17] reported improvements in patients' heel pain during the treatment phase, both patients and health professionals were aware of the treatment allocation. It is not reported whether the evaluator of outcomes was objective.

The small sample sizes and failure to conceal treatment allocations from some or all trial participants means that there are substantial threats to the validity of the conclusions produced by these trials.


    Conclusion
 Top
 Abstract
 Introduction
 Methods
 Results
 Conclusion
 References
 
Randomized controlled trials provide the best evidence on the effectiveness of health care interventions [24] as they are the only design that can address both the known and unknown biases in the estimation of the effect of treatments. This review demonstrates that while a great variety of treatments for plantar fasciitis appear in the medical literature (Tables 1 and 2GoGo), few have been evaluated using this method (Table 3Go).

The main problem with the trials included in the review was the insufficient attention to eliminating bias by concealing treatment allocation from all trial participants. None of the trials that produced statistically significant results concealed the treatment allocation from the health professionals. Without attention to the issue of concealment, internal validity is threatened, reducing the trial's value in establishing the true efficacy of interventions.

The quality of reporting of trials reviewed was generally poor with methodological assessment scores ranging from 5 to 15 out of a possible 21. The two highest methodological assessment scores were both reports of trials contained in unpublished degree dissertations [20, 21] whose authors were free from the word limitations imposed by medical journals. There was no apparent relationship between the trials' methodological scores and the conclusions they reached.

The lack of homogeneity of treatments compared in the trials prevented us from pooling data, which, given the small number of patients in the trials, might have produced evidence for the treatment of painful heels (Table 4Go). The paucity of summary statistics either published in the reports or made available after direct contact with the authors made any alternative analysis difficult. It was not possible to produce robust evidence of effectiveness for any of the treatments evaluated in the included randomized controlled trials.

These shortcomings mean that moderate degrees of benefit from the treatments may well have been missed (as have any detrimental effects). In future, trials evaluating treatments for heel pain may need to be multicentred, and the reports of all trials (but especially small studies) need to contain detailed summary statistics to enable pooling of data (meta analysis).

The trials included in this review suggest that many observed treatment effects can be explained either by placebo effects or by the spontaneous resolution of symptoms. As the natural evolution of heel pain is not fully understood, we were interested that (with the exception of the cross-over study by Powell et al. [17]) all trials included in this review reported some improvement in patients' mean pain scores in both treated and non-treated populations (Table 6Go). Given the relatively short treatment period in some trials and the long duration of some patients' pain (Table 5Go), it is possible that the observed effects can be explained due to the placebo effect patients can experience simply from participating in a trial.


    Acknowledgments
 
The authors are grateful to Nick Freemantle for his help developing the methods of the review and to Jill Ferrari for hand searching the podiatry journals. This work was made possible by a project grant from the Arthritis Research Campaign (ARC). We thank the ARC for funding, but exonerate it from the views expressed.


    References
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 Abstract
 Introduction
 Methods
 Results
 Conclusion
 References
 

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Submitted 15 September 1998; revised version accepted 28 April 1999.