Can ultrasound therapy relieve Achilles tendonitis pain?

Ultrasound Therapy for Achilles Tendonitis Pain Relief

Ultrasound therapy is not recommended as a primary treatment for Achilles tendinopathy based on current clinical guidelines, which emphasize eccentric strengthening exercises, stretching, deep friction massage, and orthotics as the evidence-based conservative treatments. 1

Guideline-Based Treatment Approach

The established conservative management for Achilles tendinopathy does not include therapeutic ultrasound as a recommended modality:

First-Line Conservative Treatments

• Eccentric strength training is the most effective and popular treatment option for Achilles tendinopathy, with strong evidence supporting its use 1
• Stretching and deep friction massage of the gastrocnemius-soleus complex are considered helpful interventions 1
• Shoe orthotics to correct overpronation or pes planus problems address underlying anatomic misalignment 1
• Heel lift orthotics can unload the tendon for pain relief 1
• Relative rest of the affected area and icing are fundamental components 1

Important Pathophysiology Context

• The condition should be labeled as "tendinosis" or "tendinopathy" rather than "tendonitis" because most cases involve chronic degenerative changes rather than acute inflammation 1, 2
• This degenerative nature means anti-inflammatory treatments may provide only temporary pain relief without addressing underlying pathology 2
• Most patients (approximately 80%) fully recover within three to six months with conservative outpatient treatment 1

Research Evidence on Ultrasound Therapy

While guidelines do not recommend ultrasound therapy, some research studies have explored its potential:

Low-Intensity Pulsed Ultrasound (LIPUS)

• A 2016 pilot study of 14 patients using LIPUS for 20 minutes daily over 8 weeks showed 50% had excellent outcomes with complete pain resolution, 14% had good outcomes, but 36% had minimal benefit 3
• A 2024 rat model study demonstrated that LIPUS increased tensile strength by approximately 30% and modulus of elasticity by approximately 53% when started early in the proliferation phase 4
• A 1989 rabbit study showed increased tensile strength and energy absorption capacity with continuous wave ultrasound at 1 W/cm² for 5 minutes daily 5

Critical Limitations

• These studies represent pilot-level or animal model evidence, and large definitive clinical trials are lacking 6
• The research does not translate to guideline-level recommendations for clinical practice 6
• Ultrasound-guided injections (a different modality) have been studied for delivering therapeutic agents, but this is distinct from therapeutic ultrasound for pain relief 6, 7

Clinical Algorithm for Achilles Tendinopathy

Follow this stepwise approach:

1. Initial 6-8 weeks: Implement eccentric strengthening exercises, calf-muscle stretching, orthotics/heel lifts, activity modification, NSAIDs for acute pain relief, and avoid peritendinous corticosteroid injections 1

2. If no improvement after 6-8 weeks: Refer to podiatric foot and ankle surgeon, continue initial treatments, consider immobilization cast or fixed-ankle walker device 1

3. Avoid: Long-term systemic corticosteroids and peritendinous injections of the Achilles tendon due to risk of tendon rupture 1

Common Pitfalls

• Do not use local corticosteroid injections for insertional Achilles tendinopathy as they are specifically not recommended and can increase rupture risk 1
• Do not rely on anti-inflammatory treatments alone, as the underlying pathology is degenerative rather than inflammatory 1, 2
• Do not pursue therapeutic ultrasound as a primary treatment when evidence-based options (eccentric exercises, stretching, orthotics) have proven efficacy 1