Short-Term Outcome of Focused Shock Wave Therapy for Sural Myofascial Pain Syndrome associated with Plantar Fasciitis: a Randomized Controlled Trial

Background. This study aims to describe prevalence and clinical features of the sural myofascial pain syndrome (SMPS) in a population affected by plantar fasciitis and to investigate if a shock wave treatment extended to the gastrocnemius-soleus trigger points is more effective in speeding up the improvement of heel pain and sural myofascial pain than a standard treatment exclusively targeted at the plantar fascia. Methods. Among 81 subjects affected by plantar fasciitis, 55 showed concomitant SMPS and were randomized to receive focused shock wave therapy for the plantar fascia and for gastrocnemius-soleus trigger points or for the plantar fascia only. We monitored heel pain (FFI-A) and foot function (FFI-B) using the Foot Function Index. Pressure pain threshold (PPT) and Delta-PPT of the gastrocnemius-soleus trigger points was assessed with a digital algometer. Outcome measures were monitored in a follow-up four weeks after the treatment. Results. The prevalence of SMPS resulted to be 67.9%. At the follow-up, no statistical significance in the comparisons between groups was found for FFI-A and FFI-B total score and also for PPT and Delta-PPT values, despite comparisons within the study group (follow-up versus baseline) showed a significant reduction of FFI-A total score (p < 0.001), FFI-B total score (p = 0.029) and Delta-PPT values (p = 0.018), with a consensual increase of PPT values (p = 0.017). Conclusions. We pointed out a high prevalence of sural trigger points in subjects affected by plantar fasciitis. In a short-term perspective, the extension of a focused shock wave treatment to the gastrocnemius-soleus trigger points resulted to be a safe but ineffective option in reducing heel pain and sural myofascial pain, if compared to a standard treatment.