Does a corticosteroid injection plus exercise or exercise alone add to the effect of patient advice and a heel cup for patients with plantar fasciopathy? A randomised clinical trial

Objective: To compare the effectiveness of patient advice plus heel cup alone (PA) versus PA and lower limb exercise (PAX) versus PAX plus corticosteroid injection (PAXI) to improve self-reported pain in patients with plantar fasciopathy. Methods: We recruited 180 adults with plantar fasciopathy confirmed by ultrasonography for this prospectively registered three-armed, randomised, single-blinded superiority trial. Patients were randomly allocated to PA (n=62), PA plus self-dosed lower limb heavy-slow resistance training consisting of heel raises (PAX) (n=59), or PAX plus an ultrasound-guided injection of 1 mL triamcinolone 20 mg/mL (PAXI) (n=59). The primary outcome was changed in the pain domain of the Foot Health Status Questionnaire (ranging from 0 'worst' to 100 'best') from baseline to the 12-week follow-up. The minimal important difference in the pain domain is 14.1 points. The outcome was collected at baseline and at 4, 12, 26, and 52 weeks. Results: The primary analysis found a statistically significant difference between PA and PAXI after 12 weeks favouring PAXI (adjusted mean difference: -9.1 (95% CI -16.8 to -1.3; p=0.023)) and over 52 weeks (adjusted mean difference: -5.2 (95% CI -10.4 to -0.1; p=0.045)). At no follow-up did the mean difference between groups exceed the pre-specified minimal important difference. No statistically significant difference was found between PAX and PAXI or between PA and PAX at any time. Conclusion: No clinically relevant between-group differences were found after 12 weeks. The results indicate that combining a corticosteroid injection with exercise is not superior to exercise or no exercise. Trial registration number: NCT03804008.