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 |