Plantar heel pain is a common foot complaint that causes significant disability and poor health-related quality of life. Foot orthoses and corticosteroid injection are effective treatments for plantar heel pain, however it is unclear if one is more effective than the other. It is also unclear whether there are characteristics that can predict who is more likely to respond to each treatment. The aim of this research was to: (i) evaluate the effectiveness of foot orthoses and corticosteroid injection, and (ii) investigate if any parameters can predict who is more likely to respond to each treatment.
A parallel-group, assessor-blinded randomised trial (the SOOTHE trial) was conducted. Participants were randomly allocated to receive either prefabricated, arch-contouring foot orthoses or a single ultrasound-guided corticosteroid injection. The primary outcome measure was the foot pain subscale of the Foot Health Status Questionnaire at 4 and 12 weeks. To define responders, response to treatment was achieved by dichotomising each participant’s overall improvement measured on a 15-point Likert scale.
A total of 103 participants aged 21 to 72 years (63 female) with plantar heel pain were recruited from the community and received an intervention. For the primary outcome of foot pain, corticosteroid injection was more effective at week 4 (adjusted mean difference 8.2 points; 95% CI 0.6, 15.8). However, foot orthoses were more effective at week 12 (adjusted mean difference 8.5 points; 95% CI 0.2, 16.8). Although these findings were statistically significant, they did not meet the previously calculated minimal important difference value of 12.5 points. The analysis of parameters that predict response is underway and will be complete prior to the conference.
Discussion and clinical relevance
Based on the findings of this trial, health professionals can advise patients with plantar heel pain that a single ultrasound-guided corticosteroid injection is effective, however the effect is relatively short-lived. However, this may be extended with appropriately contoured foot orthoses, which are more effective in the longer-term. Parameters that predict response will be discussed when the data analysis is complete.