A sincere thank you to all our readers for their interest and their valuable comments which provided important additional information to the complex field of foot pain.
We agree that heel pain is a symptom of complex causal chains which need to be accurately analyzed to enable targeted treatment. Rightfully, the importance of a shortening of the calf muscles—clinically assessed using the Silverskjöld test—is repeatedly highlighted. As mentioned in our article, dorsal flexion ≤ 0° in the talocrural joint is associated with a 23-fold increased risk of developing plantar foot pain compared to dorsal flexion of at least 10° (1).
The level of muscle stretching adapts to the functional demands and the individually required range of motion of the respective joint; here, optimal overlapping of the individual sarcomere filaments is sought to ensure delivery of maximum muscle force. Prolonged muscle training across the full range of motion of the joint leads to an increased degree of sarcomere stretching, inducing growth processes based on serial sarcomere addition to achieve optimum filament overlapping to produce maximum force. Conversely, muscular inactivity with permanently reduced range of motion of the joint results in sarcomere reduction and consequently shortening off the muscle (2). The normal position of the calcaneus in relation to the tibial axis is slightly valgus. In patients with shortened calf muscles, the pronation of the calcaneus is further increased by increased muscle traction on the slightly eccentric position of the calcaneus.
The acentric (from dorsal-caudal-lateral to ventral-cranial-medial) joint axis of the subtalar joint, in combination with the increased calcaneal pronation, contributes to increased mechanical stress on the plantar fascia with increased micro-trauma risk on exertion.
Also important is the comment that bilateral ultrasound examination of the origin of the plantar fascia with comparison of the sides can be a useful strategy to document the course of treatment. As a means of primary diagnostic assessment, however, ultrasound is of limited value, because the origin of the plantar fascia can be thickened (>4 mm) in asymptomatic patients too (3).
We would like to thank Prof. Niewald for the important information that prospective randomized controlled trials have demonstrated the superiority of radiotherapy over “placebo” irradiation . The current version of the S2-guideline for radiation therapy of benign diseases even contains a “shall” recommendation for radiation therapy, if indicated (painful plantar fasciitis of more than 3 months’ duration, exhaustion of other conservative methods, patient age between 30 and 40 years). The success of treatment varies between studies, a pain-free state was reportedly achieved in 13% to 81% of patients and pain alleviation in up to 90% of patients. These results underline the relevance of this treatment approach among the conservative treatment options available (4).
Also highly valuable is the letter by Prof. Dr. Knobloch et al. with information about the most recent development with regard to the reimbursement of the cost of extracorporeal shockwave therapy (ESWT) by the statutory health insurances. We think that, against this background, the successful treatment with significant pain reduction, demonstrated in double-blind, randomized controlled trials, justifies the inclusion of ESWT as an integral part of the treatment concept for chronic plantar heel pain after a period of 6 months.
In summary, it can be said that plantar foot pain can be successfully treated with a variety of conservative treatment strategies. The composition of the various treatment components should be decided on a case-to-case basis. In agreement with the contributions to the discussion, a conceivable concept for the conservative treatment approach is to prescribe, when physiotherapy and potentially fitting of insoles were unsuccessful, after 3 months radiotherapy and after 6 months ESWT.
PD Dr. med. Natalia Gutteck
Department für Orthopädie, Unfall- und Wiederherstellungschirurgie
Martin-Luther-Universität, Halle-Wittenberg, Germany
Conflict of interest
The authors declare no conflict of interest.
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|3.||Ehrmann C, Maier M, Mengiardi B, Pfirrmann CWA, Sutter R: Calcaneal attachment of the plantar fascia: MR findings in asymptomatic volunteers. Radiology 2014; 272: 807–14 CrossRef MEDLINE|
|4.||Mücke R, Micke O, Seegenschmiedt MH (ed.): DERGO – Leitlinien in der Strahlentherapie: „Strahlentherapie gutartiger Erkrankungen“ Version 2.0 vom 2018. www.degro.org/wp-content/uploads/2018S2-Leitlinie-Strahlentherapie-gutartiger-Erkrankungen-update-2018-Endversion.pdf. (last accessed on 27 May 2019).|
|5.||Gutteck N, Schilde S, Delank KS: Pain on the plantar surface of the foot. Dtsch Arztebl Int 2019; 116: 83–8 VOLLTEXT|