Understanding Achilles Tendinopathy

Information for Patients

What is Achilles Tendinopathy?

Achilles tendinopathy is a common condition that causes pain, stiffness, and swelling in the Achilles tendon – the strong cord connecting your calf muscles to your heel bone. It's not usually caused by inflammation (like a 'tendinitis'), but rather by a series of small tears and structural changes in the tendon over time. This is often due to overuse or overloading the tendon beyond its capacity.

Think of it as the tendon struggling to keep up with the demands placed on it, leading to a 'failed healing' response.

Healthy Tendon vs. Tendinopathy

Illustration of Healthy vs. Tendinopathic Achilles Tendon Healthy Tendon Organised, parallel fibres Tendinopathy Disorganised fibres & new vessels/nerves

Healthy Tendon

  • Organised, parallel fibres
  • Strong & efficient
  • Normal blood flow

Tendinopathy

  • Disorganised, messy fibres
  • Weakened & less efficient
  • New nerve & vessel growth (pain source)

What Causes It? Common Risk Factors

Factors About You (Intrinsic)

  • Decreased calf strength or flexibility.
  • Foot posture (e.g., flat feet or very high arches).
  • Increasing age and being overweight.
  • Associated medical conditions like diabetes or high cholesterol.

Factors You Do (Extrinsic)

  • Sudden increase in training (e.g., running distance or speed).
  • Changing your training surface (e.g., from grass to road).
  • Poorly supportive footwear.
  • Excessive hill running.

How Can I Manage It?

Recovery is an active process that takes time and patience. The key is to manage the load on your tendon and gradually build its strength back up.

  1. Modify, Don't Stop: Find a level of activity that doesn't significantly increase your pain. This might mean shorter walks, less running, or switching to swimming or cycling. Complete rest is often unhelpful.
  2. Strengthen It: The most important part of treatment is a targeted exercise program from a physiotherapist. This involves specific types of calf raises to stimulate healing and build tendon strength.
  3. Check Your Footwear: Ensure your shoes are supportive and not worn out. Sometimes a small heel lift insert can provide temporary relief.
  4. Be Patient: Tendons heal slowly. A consistent exercise program over 3-6 months is often needed to see significant improvement.

Achilles Tendinopathy: A Clinical Overview

A Guide for Healthcare Professionals

Pathophysiology

The condition is best understood as a failed healing response. Instead of inflammation, the tendon undergoes a degenerative process. Key features include:

  • Collagen Disarray: Disorganisation and separation of collagen fibres, with a shift from predominantly Type I collagen to an increase in weaker Type III collagen.
  • Cellular Changes: An increase in the number of tenocytes (tendon cells) and changes in their shape from elongated to rounded.
  • Neovascularisation: Ingrowth of new, disorganised blood vessels, often accompanied by sensory nerve fibres, which is thought to be a source of pain.
  • Increased Ground Substance: An increase in the non-collagenous matrix (e.g., glycosaminoglycans and proteoglycans), leading to tendon thickening.

This process weakens the tendon's structure, reducing its capacity to handle tensile loads.

Aetiology: Causes and Risk Factors

Achilles tendinopathy results from excessive cumulative load on the tendon, exceeding its capacity to repair and adapt. Risk factors can be divided into intrinsic and extrinsic categories.

Intrinsic Factors (Patient-related)

  • Age: Most common in individuals aged 30-50.
  • Genetics: Certain gene polymorphisms may predispose individuals.
  • Biomechanical Issues: Poor foot mechanics, calf muscle weakness/tightness, reduced ankle dorsiflexion.
  • Medical Conditions: Obesity, hypertension, diabetes, hypercholesterolaemia.
  • Medications: Fluoroquinolone antibiotics, long-term corticosteroid use.

Extrinsic Factors (Activity-related)

  • Overuse: Sudden increases in training intensity, duration, or frequency.
  • Poor Technique: Incorrect form during sporting activities.
  • Inappropriate Footwear: Lack of support or cushioning.
  • Training Surface: Consistently running on hard or sloped surfaces.

Clinical Presentation: History and Examination

History

  • Insidious Onset: Pain developed gradually.
  • Activity-Related Pain: Worse at start, improves during, worse after.
  • Morning Stiffness: Classic feature.
  • Localised Pain: Patient can pinpoint the area.

Examination

  • Inspection: Localised swelling, fusiform (mid-portion) or bony prominence (insertional).
  • Palpation: Localised tenderness, may feel thickened/nodular.
  • Range of Motion: Pain with active/passive dorsiflexion.
  • Functional Assessment: Pain on single-leg heel raise or hop.

Diagnosis: Key Criteria, Special Tests & Investigations

Diagnosis is primarily clinical.

Special Tests

Painful Arc Sign

Area of tenderness moves proximally with dorsiflexion.

Watch Demo
Royal London Hospital Test

Pain reduces on palpation when tendon is under tension (dorsiflexion).

Watch Demo

Relevant Investigations

  • Imaging not usually required.
  • Ultrasound: Modality of choice. Shows thickening, hypoechoic areas, neovascularisation.
  • MRI: For complex cases or pre-op planning.

Differential Diagnoses

Condition Key Differentiating Features
Achilles Tendon RuptureAcute onset, "pop", palpable gap, positive Simmonds' triad.
Retrocalcaneal BursitisPain anterior to tendon insertion; positive "two-finger squeeze" test.
Sever's DiseaseSkeletally immature patients (8-14 yrs); pain on calcaneal squeeze.
Haglund's DeformityBony prominence on posterior calcaneus.
Sural Nerve EntrapmentPain/paraesthesia on lateral foot/heel.
Referred Pain (S1 Radiculopathy)Associated back pain, dermatomal/myotomal changes.

Management: Treatment Strategies

Education and Load Management

  • Explain Diagnosis: Degenerative, not inflammatory. Recovery takes time.
  • Activity Modification: Relative rest, not complete. Modify provocative activities. Keep pain < 4/10.

Exercise Therapy

  • Isometric Loading: For early analgesia.
  • Isotonic (Heavy Slow Resistance): Current best practice.
  • Eccentric Loading: Can be provocative for insertional tendinopathy.

Adjunctive Therapies

  • Footwear/Orthotics: Supportive shoes, temporary heel lift.
  • Pharmacological:
    • Analgesia: Paracetamol, topical NSAIDs.
    • Oral NSAIDs: Short-term use only.
    • Corticosteroid Injections: Contraindicated.

Other Interventions (Specialist Referral)

  • ESWT: If no response after 3-6 months of active load management.
  • Specialist Injections (PRP etc.): Mixed evidence base.
  • Surgery: Last resort after 6-12 months of failed conservative management.

Complications

  • Chronic Pain and Disability: Can become persistent, limiting activity.
  • Achilles Tendon Rupture: Degenerative process increases risk of tear.

General Information on Tendinopathies

Summary of the most recent therapeutic guidelines

Features of a Progressive Loading Program

A progressive loading program should involve:

  • Gradual return to physical activity
    • This may reduce the risk of reinjury and prevent deconditioning.
    • It may not affect long-term outcomes of tendinopathy.
    • Example: For lower limb tendinopathy, start with a slow-walking program and gradually build towards reintroducing the desired physical activity (e.g., running).
  • Start an eccentric-concentric loading program
    • This may promote positive effects on the tendon's structural integrity and load-bearing properties.
    • Other forms of reduced-loading programs that do not cause tendon damage may also be appropriate.
  • Monitor and adjust the tendon loading
    • If pain after exercise increases by at least 2 points on a 10-point pain-score scale, reduce the load on the tendon for several days.
    • Return to exercise at a lower load when pain improves.

Note: In eccentric contraction, the muscle is lengthening during contraction (e.g., downward phase of a biceps curl). In a concentric contraction, the muscle is shortening (e.g., upward phase of a biceps curl).

Management for Tendinopathic Tears

Nontraumatic (degenerative) tears should be distinguished from acute traumatic tears as the management differs. Acute traumatic tears are associated with a specific event of sufficient force.

  • Partial traumatic tears and tendinopathic microtears are usually managed nonsurgically.
  • Partial traumatic tears can progress to complete tears, and surgical referral at this stage may be appropriate.

Pharmacological Management

Oral analgesics are often not very effective; however, a trial of simple analgesia is reasonable initially.

  • Local peritendinous corticosteroid injections to non-weightbearing tendons may be useful for short-term pain relief (lasting 6 to 8 weeks).
  • They do not appear to alter the pathology or have any effect on long-term outcomes.
  • Injections should not be used if major weightbearing tendons (e.g., Achilles, patellar, tibialis posterior) are involved. Seek specialist advice.

Management Strategies with No Benefit and Potential Harm

The following injection therapies are not recommended for the management of tendinopathy because of insufficient evidence of benefit:

  • Stem cells
  • Autologous whole blood
  • Platelet-rich plasma (PRP)
  • Platelet-rich fibrin matrix
  • Polidocanol (a sclerosing agent)
  • Prolotherapy (injection of an irritant solution)

Source Information

The information on this page is a summary based on Therapeutic Guidelines.

Visit Therapeutic Guidelines Home Page