What is the role of cortisone (corticosteroid) injections in treating plantar fasciitis?

Corticosteroid Injections for Plantar Fasciitis

Corticosteroid injection combined with controlled training (strength training and stretching) is the most effective treatment for plantar fasciitis and should be your first-line approach when conservative measures fail. 1

Treatment Algorithm

Initial Conservative Management (First 4-6 weeks)

• Start with NSAIDs and relative rest, avoiding activities that provoke pain 2
• Apply ice therapy to reduce acute inflammation 2
• Prescribe cushioning shoes and insoles during the initial treatment period 1
• Patients should abstain from running and jumping activities 1

When to Inject Corticosteroids

• Consider corticosteroid injection for persistent pain despite 4-6 weeks of NSAID treatment 2
• Do not use corticosteroid injection as monotherapy - the evidence strongly supports combining it with supervised physical therapy for superior outcomes 1

Injection Technique and Safety

Critical Safety Considerations

• Never inject directly into the tendon substance - this significantly increases rupture risk 3
• Target the injection to the plantar fascia attachment at the medial tubercle of the calcaneal tuberosity 4
• Consider ultrasound guidance when available to improve accuracy and reduce complications 3
• The plantar fascia rupture rate is approximately 2.4% following corticosteroid injection, with higher risk in patients with elevated BMI (average BMI 38.6 kg/m² in rupture cases) 5

Dosing Protocol

• Administer injections at monthly intervals until ultrasound-measured plantar fascia thickness is less than 4.0 mm 1
• Maximum of 3 injections should be given 1
• This protocol is based on the highest quality randomized controlled trial showing superior long-term outcomes 1

Mandatory Concurrent Physical Therapy

The injection must be combined with a structured 3-month program of strength training and stretching - this combination produces clinically meaningful improvements of 40 points on the Foot Function Index and 20 mm on VAS pain scores compared to training alone 1. The evidence from this 2019 randomized controlled trial with 2-year follow-up demonstrates:

• Combined treatment (injection + training) is superior to either treatment alone at all time points 1
• The difference between combined treatment and injection alone was 29 points on FFI and 17 mm on VAS - both clinically relevant 1
• Benefits persist long-term, making this the evidence-based first-line approach 1

Physical Therapy Components

• Begin supervised exercises once acute pain subsides 2
• Focus on progressive strengthening of hip flexors and plantar fascia 2
• Include stretching exercises as part of the 3-month protocol 1
• Land-based exercises are preferred over aquatic therapy 2

Expected Outcomes and Monitoring

• Pain reduction should be evident within 3 weeks of combined treatment 6
• Monitor using patient-reported pain levels (VAS) and functional assessment (Foot Function Index or AOFAS scores) 1, 6
• At 3-month follow-up, expect VAS pain scores to decrease from approximately 7.4 to 2.5 and AOFAS scores to improve from approximately 52 to 88 6

Common Pitfalls to Avoid

The most critical error is using corticosteroid injection as standalone therapy without concurrent physical therapy - this produces inferior outcomes compared to the combined approach 1. Additionally, avoid:

• Injecting near the Achilles, patellar, or quadriceps tendons due to rupture risk 3
• Performing more than 3 injections, as this increases complication risk without additional benefit 1
• Allowing patients to immediately return to high-impact activities - maintain activity modification during the 3-month treatment period 1

Alternative Considerations

If corticosteroid injection is contraindicated or fails after appropriate combined treatment, platelet-rich plasma injection shows comparable or superior efficacy to corticosteroids at 3-month follow-up, with mean VAS scores improving from 7.44 to 2.52 6. However, the evidence for PRP combined with training is less robust than for corticosteroids.