Tendinopathy
Chronic tendon disorder characterised by pain, swelling, and impaired function, most commonly affecting the Achilles, patellar, and rotator cuff tendons. Pathology involves failed healing rather than inflammation.
Key Facts
- Commonest sites: Achilles, patellar, rotator cuff (supraspinatus), lateral epicondyle (tennis elbow), medial epicondyle (golfer's elbow)
- Pathology: failed healing response - disorganised collagen, neovascularisation, mucoid degeneration; NOT primarily inflammatory
- Terminology: 'tendinopathy' preferred over 'tendinitis' (histologically not inflammatory)
- First-line treatment: activity modification, eccentric exercise programme (Alfredson protocol for Achilles - 12 weeks)
- Corticosteroid injection: short-term pain relief but may weaken tendon and increase rupture risk; generally avoided for Achilles
- Risk factors: overuse/repetitive strain, fluoroquinolone antibiotics, corticosteroids, diabetes, renal disease, age >40
- USS/MRI: thickened, hypoechoic tendon with neovascularisation; partial tears may be seen
- Fluoroquinolones: important drug cause of tendinopathy/rupture (especially Achilles); black box warning
Overview
Key Facts
Tendinopathy is a clinical syndrome of chronic tendon pain and dysfunction, most commonly due to overuse. The underlying pathology is degenerative rather than inflammatory.
Epidemiology
- Extremely common musculoskeletal complaint
- Achilles tendinopathy: ~6% lifetime incidence in sedentary, higher in athletes
- Rotator cuff tendinopathy: most common cause of shoulder pain
- Tennis elbow (lateral epicondylitis): ~1–3% of adults
Aetiology
- Repetitive overload/overuse
- Intrinsic: age >40, poor biomechanics, muscle weakness/imbalance
- Extrinsic: training errors, inappropriate footwear
- Drugs: fluoroquinolones (ciprofloxacin, levofloxacin), corticosteroids
- Systemic: diabetes, CKD, hypercholesterolaemia, inflammatory arthritis
Pathophysiology
- Not primarily inflammatory - failed healing response
- Disorganised collagen (loss of parallel arrangement)
- Neovascularisation and nerve ingrowth (pain)
- Mucoid/myxoid degeneration
- Ground substance accumulation
- Cook & Purdam continuum: reactive tendinopathy → tendon dysrepair → degenerative tendinopathy
Clinical Presentation
General
- Gradual onset pain with activity, initially improving with warm-up
- Localised tenderness over affected tendon
- Morning stiffness
- Progressive worsening if continued overload
Site-Specific
- Achilles: pain at insertion or mid-portion; worse walking uphill/stairs
- Patellar: anterior knee pain; worse jumping/squatting
- Rotator cuff (supraspinatus): painful arc 60–120°; night pain
- Lateral epicondyle (tennis elbow): lateral elbow pain; worse gripping, wrist extension
- Medial epicondyle (golfer's elbow): medial elbow pain; worse wrist flexion
Red Flags
- Sudden pain/pop (tendon rupture - especially Achilles)
- Systemic features (consider inflammatory arthritis)
- Bilateral tendon pain on fluoroquinolones (stop immediately)
- Night pain not improving with rest (consider malignancy)
Differential Diagnosis
| Diagnosis | Key Features | Investigation |
|---|---|---|
| Tendon rupture | Sudden pain, palpable gap, loss of function | USS, clinical (Thompson test for Achilles) |
| Bursitis | Swelling over bursa, pain on compression | USS, clinical |
| Inflammatory arthritis | Synovitis, morning stiffness >1h, multi-site | RF, anti-CCP, ESR |
| Stress fracture | Focal bone tenderness, worsening with activity | MRI |
| Nerve entrapment | Paraesthesiae, nerve territory distribution | Nerve conduction studies |
Diagnosis / Investigation
Imaging
- USS: first-line; thickened, hypoechoic tendon, neovascularisation, partial tears
- MRI: increased signal on T2; useful for rotator cuff tear assessment
- X-ray: calcific tendinopathy (calcification within tendon); enthesophytes
Bloods
- Generally not needed
- If systemic cause suspected: ESR, CRP, RF, HbA1c, U&Es, TFTs, cholesterol
Management
Non-pharmacological (FIRST-LINE)
- Activity modification: relative rest (avoid aggravating activities but maintain general activity)
- Eccentric exercise programme: gold standard (e.g., Alfredson protocol for Achilles - 3 × 15 reps, twice daily, 12 weeks)
- Physiotherapy: progressive loading, biomechanical assessment
- Ice/heat: for symptom relief
- Orthotics/bracing: heel lifts (Achilles), counterforce brace (tennis elbow)
Pharmacological
- Paracetamol/NSAIDs: short-term pain relief (topical diclofenac preferred for localised)
- Corticosteroid injection: limited role; short-term relief (<6 weeks) but may weaken tendon
- Avoid for Achilles (rupture risk)
- Tennis elbow: worse long-term outcomes vs physiotherapy alone
- GTN patches: some evidence for chronic tendinopathy (off-label)
Surgical/Interventional
- Shockwave therapy (ESWT): calcific tendinopathy, chronic Achilles, plantar fasciitis
- PRP injection: emerging evidence (mixed); not routinely recommended by NICE
- Surgery: debridement/decompression for refractory cases (6–12 months conservative failure)
Referral Criteria
- Physiotherapy: all (exercise prescription)
- Orthopaedics/sports medicine: refractory to 3–6 months conservative; suspected tear
- Rheumatology: if inflammatory cause suspected
Prognosis
- ~80% improve with appropriate conservative management over 3–6 months
- Eccentric exercise: ~60–90% success rates
- Recurrence: common if underlying cause not addressed
- Corticosteroid injection: short-term benefit but higher recurrence and possible tendon weakening
- Fluoroquinolone-related: usually resolves on stopping drug; can persist
- Surgery: ~75–85% good outcomes for refractory cases
Other Relevant Information
Cook & Purdam Tendinopathy Continuum
| Stage | Features | Management |
|---|---|---|
| Reactive | Non-inflammatory, reversible, in response to acute overload | Load modification, isometric exercise |
| Dysrepair | Attempted healing, matrix disorganisation, neovascularisation | Eccentric exercise, avoid provocative load |
| Degenerative | Irreversible structural change, cell death, poor healing capacity | Modified loading, may need surgery |