Ultrasound guided corticosteroid injection for plantar fasciitis: randomised controlled trial
BMJ 2012; 344 doi: https://doi.org/10.1136/bmj.e3260 (Published 22 May 2012) Cite this as: BMJ 2012;344:e3260
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Response to Dr Lankhorst and colleagues
In relation to the generalisability of our findings, we believe that participants enrolled in the trial represented the typical characteristics of people with plantar fasciitis, with the exception of a slightly larger sample of males. Regarding BMI, a systematic review including 13 case-control studies and 3 case-series reports has shown that increased BMI is the most important risk factor for plantar fasciitis,1 with one included study showing that obese participants (BMI > 30 kg/m²) were over 5 times more likely than a referent group (BMI < 25 kg/m²) to have the condition (odds ratio = 5.6, 95% confidence interval = 1.9 to 16.6, P < 0.01).2 The review also identified a convincing relationship between plantar fasciitis and increased age (particularly 45 to 60 years). This has also been shown in a study of military personnel (who are typically very active) where the condition mostly affected recruits aged over 40 years.3 Therefore, we believe that the mean BMI (31.2 kg/m²) and age (52.7 years) of participants in our study are typical for the condition, and that these factors do not limit the external validity of our findings. Nonetheless, we acknowledge that plantar fasciitis is also a common running-related injury4 5 and that our trial did not involve many athletes. Several enquiries were received from recreational and competitive runners during recruitment for the trial, but most of these declined to participate because a rest period from running was recommended following the steroid injection.
Regarding the reduced plantar fascia swelling in the dexamethasone group, the 4.0 mm threshold value was used as an eligibility criterion only, and the difference between groups for plantar fascia thickness at baseline (see Figure 4) would not have been accounted for if a raw threshold for improvement had been used. Therefore, rather than dichotomising raw scores for plantar fascia thickness at each time point (i.e. less than or greater than 4.0 mm), we incorporated a minimum ‘change score’ instead. Accordingly, we dichotomised plantar fascia thickness data by considering that a true improvement in plantar fascia thickness occurred when it was shown to have reduced by more than -0.7 mm. This value was derived from the 95% limits of agreement for measuring plantar fascia thickness by ultrasound.6 Based on this criterion, the number needed to treat (which incorporates the success rates for each group) for a true change in plantar fascia thickness at four weeks was 3.15 (95% confidence interval 2.00 to 7.35). This calculation was presented in the Discussion section of the trial paper.7 Furthermore, as measurement error for plantar fascia thickness is less than -0.7 mm for 95% of examinations with ultrasound,6 the mean improvement observed in the dexamethasone group at 12 weeks (0.93 mm) was greater than the error margin.
Finally, in relation to the cut-off point used for calculating the number needed to treat for pain at four weeks (19.5 points on the pain domain of the FHSQ), this value is 1.5 times the minimal important difference (MID) for the outcome measure.8 The cut-off value was determined by considering that a reasonable improvement in pain (not a minimal improvement in pain) from a patient’s perspective occurred when pain levels were reduced by 1.5 times the MID. This reasoning was presented in the Discussion section of the trial paper.7
Response to Dr Nair
Based on the available literature, we disagree that corticosteroid injection is equivocal in efficacy to simple conservative measures (such as foot orthoses / heel cushions). For example, systematic reviews9 10 have identified a randomised trial that compared three interventions for treatment of plantar fasciitis: (i) local corticosteroid injection alone (20 mg triamcinolone), (ii) foot orthoses alone, and (iii) corticosteroid injection plus foot orthoses.11 The results indicated that when compared to foot orthoses and the combined treatment, corticosteroid injection alone was associated with significantly lower heel pain at eight and twelve weeks following treatment (100 mm VAS, weighted mean difference = -45.0 mm, 95% CI = -59.1 to -30.9).
In addition, a retrospective cohort study has reported patient satisfaction levels for a variety of non-operative interventions, including corticosteroid injection.12 This study involved 411 patients presenting to an orthopaedic surgeon over a 10 year period for management of plantar fasciitis. Throughout this period, patients were asked to rank the effectiveness of various conservative treatments on a five-point ordinal scale developed by the study author. The results of this process showed that compared to other interventions offered, corticosteroid injection was the second most effective treatment (cast-immobilisation being the first) and was associated with significantly higher satisfaction compared to insoles, heel pads, oral pain medication, heel cups and use of athletic footwear (P < 0.001).
In relation to ultrasound guided versus non-ultrasound guided techniques, our trial was not designed to compare these injection methods. Rather, we believe the objective of our trial, to test the effectiveness of ultrasound guided corticosteroid injection against placebo, has been clearly outlined in the publication. The use of continuous ultrasound guidance for our injections demonstrates that the corticosteroid was administered into the area of plantar fascia swelling (rather than the surrounding soft tissue), and the outcomes reported are therefore a result of this specific intervention. It is hoped that by showing where the infiltration occurred (e.g. by the video link included in the Methods section of the paper7: http://www.youtube.com/watch?v=F5nsEMypmlg&feature=email) clinicians using ultrasound at the point of care can replicate the procedure, thereby improving generalisation of the trial findings.
Regarding the advantage of ultrasound guidance while performing plantar fascia injections, we are aware of two small studies with conflicting findings. One study randomly allocated participants to receive a corticosteroid injection by either a traditional palpation method or an ultrasound-guided technique.13 Follow-up occurred at approximately 13 weeks and no significant difference between groups was found for pain levels at this time point. However, a subsequent study used a similar design and reported significantly lower pain levels (at two weeks, two months and twelve months) among participants receiving injection with ultrasound guidance versus a palpation technique.14 In addition to these studies, a systematic review of 11 randomised trials comparing ultrasound guidance versus landmark-based techniques for shoulder, wrist, knee and ankle injections has also shown a short-term advantage with the modality.15
Reference list
1. Irving DB, Cook JL, Menz HB. Factors associated with chronic plantar heel pain: a systematic review. J Sci Med Sport 2006;9(1-2):11-22; discussion 23-4.
2. Riddle DL, Pulisic M, Pidcoe P, Johnson RE. Risk factors for plantar fasciitis: a matched case-control study. J Bone Joint Surg 2003;85(5):872-77.
3. Scher DL, Belmont PJ, Bear R, Mountcastle SB, Orr JD, Owens BD. The incidence of plantar fasciitis in the United States military. J Bone Joint Surg 2009;91:2867-72.
4. Taunton JE, Ryan MB, Clement DB, McKenzie DC, Lloyd-Smith DR, Zumbo BD. A retrospective case-control analysis of 2002 running injuries. Br J Sports Med 2002;36:95-101.
5. Lysholm J, Wiklander J. Injuries in runners. Am J Sports Med 1987;15(2):168-71.
6. Wearing SC, Smeathers JE, Yates B, Sullivan PM, Urry SR, Dubois P. Sagittal movement of the medial longitudinal arch is unchanged in plantar fasciitis. Med Sci Sports Exerc 2004;36(10):1761-67.
7. McMillan AM, Landorf KB, Gilheany MF, Bird AR, Morrow AD, Menz HB. Ultrasound guided corticosteroid injection for plantar fasciitis: randomised controlled trial. Br Med J 2012;344:e3260.
8. Landorf KB, Radford JA, Hudson S. Minimal Important Difference (MID) of two commonly used outcome measures for foot problems. J Foot Ankle Res 2010;3(7).
9. Crawford F, Thomson C. Interventions for treating plantar heel pain. Cochrane Database Syst Rev 2003(3):CD000416.
10. Landorf K, Menz H. Plantar heel pain and fasciitis. BMJ Clin Evid 2008;02:1111.
11. Kriss S. Heel pain: an investigation into its etiology and management. University of Westminster [thesis], 1990.
12. Gill LH, Kiebzak GM. Outcome of nonsurgical treatment for plantar fasciitis. Foot Ankle Int 1996;17(9):527-32.
13. Kane D, Greaney T, Shanahan M, Duffy G, Bresnihan B, Gibney R, et al. The role of ultrasonography in the diagnosis and management of idiopathic plantar fasciitis. Rheumatology 2001;40:1002-08.
14. Tsai W, Hsu C, Chen C, Chen M, Yu T, Chen Y. Plantar fasciitis treated with local steroid injection: comparison between sonographic and palpation guidance. J Clin Ultrasound 2006;34(1):12-16.
15. Gilliland CA, Salazar LD, Borchers JR. Ultrasound versus anatomic guidance for intra-articular and periarticular injection: a systematic review. Phys Sportsmed 2011;39(3):121-31.
Competing interests: No competing interests
We appreciate the trial performed by McMillan and colleagues, that was published in May 2012 (1), for the nicely performed randomized trial. The authors conclude that an injection with dexamethasone is safe, and effective for the short term treatment of plantar fasciitis. However, after reading the author’s conclusion some questions remained.
The authors state in the limitations section that a factor that limits the generalizability of the results, is the large proportion of men in the patient group. However, we think that other patient characteristics are also limiting the generalizability of the results. For instance, the studied population had an average BMI of 31 and a relatively long duration of complaints. Therefore, one should take into account that the group of patients examined in this study is a specific group of patients, and does not represent the young and active group of patients in which plantar fasciitis also often occurs.
In addition, one of the inclusion criteria was a minimum thickness of the plantar fascia of 4.0 mm. The authors conclude that the treatment significantly reduces abnormal swelling after four weeks. However, after 12 weeks of follow-up none of the participants had a fascia thickness of 4.0 mm or less and the mean decrease was only 0.93 mm. The authors do however suggest that a dexamethasone injection decreases the fascia thickness. The differences found might be the result of a measurement error and do not seem to be clinically relevant.
Finally, as stated in the first part of discussion, no clinical relevant difference was found for pain relief. Consequently, the authors dichotomized the pain data, and choose for the cut-off point of 19.5. Unfortunately, the chosen cut-off point is not further explained. According to this cut-off value the number needed to treat was 2.93. The conclusion of the authors that treatment with dexamethasone is effective in the short term treatment of fasciitis plantaris is based on this finding. However, in the protocol(2), a difference of 13 points was described as clinically relevant only a difference of 11 points was found in the current study.
Therefore, we believe that this additional information is necessary to interpret the conclusion in a right way.
1. McMillan AM, Landorf KB, Gilheany MF, Bird AR, Morrow AD, Menz HB. Ultrasound guided corticosteroid injection for plantar fasciitis: randomised controlled trial. BMJ 2012;344:e3260.
2. McMillan AM, Landorf KB, Gilheany MF, Bird AR, Morrow AD, Menz HB. Ultrasound guided injection of dexamethasone versus placebo for treatment of plantar fasciitis: protocol for a randomised controlled trial. J Foot Ankle Res 2010;3:15.
Competing interests: No competing interests
Sir,
We read with great interest, the research article by McMillan et al on ‘Ultrasound guided corticosteroid injection in plantar fasciitis: randomised controlled trial’.
Their research found that ultrasound (US) guided steroid injection provides short time relief from pain in plantar fasciitis up to four weeks and improvement in plantar fascia swelling up to 12 weeks. It is a well conducted research but we would like to raise a few issues.
Plantar fasciitis is usually a self-limiting condition and most patients improve with general measures like foot care advise, stretching calf and foot, heel cushions, heel strapping and non-steroidal anti-inflammatory drugs (NSAIDs). Benefits of local steroids are equivocal and at best transient.
The authors have excluded populations of patients who have inflammatory arthritis (usually sero-negative type) and Diabetes mellitus, who usually have a resistant disease and commonly present themselves to primary and secondary care. It would have been useful to know how these patients responded, had they been included.
Although the title of the article is ultrasound guided steroid injection, there is no comparison with blind steroid injection into the plantar fascia and therefore, it does not convince the readers on the merits of US guidance in these procedures. So the question arises why we should do an US guided injection when this could be done without an US. Was the author’s intention just to highlight the merits of a steroid injection in plantar fasciitis? In a sense, we find the title misleading!
It is not clear whether the patients received any medications which may have had an impact on treatment responses. The applicability of this intervention (local nerve block and US guided steroid injection) in primary or secondary care is limited as it needs training, logistical support including US machines and has cost implications.
We agree with the usefulness of US in diagnosis and measurement of plantar fascia thickness but do not think that the above research convinces us of any advantages of using US for guiding steroid injection in plantar fasciitis.
We declare that there are no conflicting interests.
Best regards
Competing interests: No competing interests
Re: Ultrasound guided corticosteroid injection for plantar fasciitis: randomised controlled trial
Whether one calls it ‘Plantar Fasciitis’ (for which term there is little histological evidence ) or ‘Bruised Heel’ ( which reflects perhaps it’s commonest aetiology ), sufferers from this common and disabling condition should be grateful that this paper makes it less likely that they will be offered steroid injections. Even with,but particularly without, a posterior tibial nerve block, injections into the heel are not for the faint hearted. Especially when the outcome after 4 weeks is unremarkable.
The authors suggest that immobilisation in Plaster may be the most effective option.
This does not reflect the anecdotal impressions of many sufferers and practitioners, who have found that a more simplistic approach has much to commend it.
We all recognise that bruising of subcutaneous tissues rapidly resolves, if the causative trauma is not repeated.
Careful histories taken from bruised heel patients often reveal that the symptoms began after a change of footwear, or a change in walking habit. New shoes, looser ones, flipflops, boots of any sort, are mentioned. Unusual exercise, walking on hard surfaces, even jumping from a height, are often remembered.
No doubt the majority of people who develop bruising of the heel tissues in such circumstances, experience rapid resolution, if they avoid the type of repetitive minor trauma which seems so important in those with chronic symptoms.
Examining the footwear, and the gait, of chronic sufferers, is vital.
Most will have shoes that are insufficiently close fitting, and which allow the heel of the shoe or sandal to tap the heel tissues of the wearer, on every step that is taken.
Many chronic sufferers will have an odd gait , walking on the lateral aspect of the affected foot.
There may be demonstrable weakness of their intrinsic foot muscles.
If these common features are found and their natural history understood, a good prognosis can be confidently given.
Shoes should have air cushion heels.Avoid flip flops and boots of all sorts.
Wear thick socks, maybe two pairs, so that the foot and shoe move as one, preventing the heel of the shoe tapping against bruised tissues at every step.
Chronic sufferers may not recover fully, until their weak intrinsic foot muscles are strengthened, restoring a normal gait. They need to be carefully taught how to elevate their mid foot, initially for seconds at a time, while keeping heel and toe pads flat on the ground.
Those who find these exercises difficult, may get similar effect from walking uphill or upstairs, using their toes and forefoot as a propulsive lever on every pace.
This safe, cheap and satisfying approach is worth a try.
Approached in this way, bruised heel is one of a triad of disabling conditions that affect multitudes, for want of simple muscle strengthening, based on clinical awareness.
Knee pain and dysfunction, acute and chronic, may not resolve or improve, without conscientious Quads exercises.
Recurrent ankle instability will not improve without attention to the lower leg muscles and the proprioceptive reflex arc.
Competing interests: No competing interests