Tendinitis and tendinopathy

Main tendinopathies by location

Pathophysiology — Tendinous Continuum Model

• Stage 1 - Reactive Tendinopathy Rapid adaptive response (non-inflammatory) to acute overload → nodular thickening of the tendon + increased matrix → reversible if load is reduced quickly → do not stop activity completely (tendon atrophy) → manage load
• Stage 2 - Dysrepair (early tendinosis): disorganized repair attempt + vascular ingrowth + abnormal cell proliferation → partially reversible → essential progressive rehabilitation
• Stage 3 - Degenerative Tendinosis: major collagen disorganization + acellular areas + calcifications + abundant neovascularization → little to no structural reversibility + but can become asymptomatic with rehabilitation + high risk of rupture
• Intrinsic risk factors: Age (> 35 years) + female sex (estrogen effect on collagen) + diabetes (collagen glycosylation) + hypercholesterolemia (intra-tendinous lipid deposits) + fluoroquinolones (direct tenocyte toxicity → risk of tendon rupture - particularly Achilles tendon) + systemic corticosteroids
• Extrinsic risk factors Too rapid increase in training volume or intensity (10% rule % per week) + poor running or movement technique + unsuitable equipment (shoes) + playing surface

Treatment — stepped approach

• Fundamental Principle — Load Management: The tendon needs mechanical load to regenerate (load stimulates tenocytes + collagen synthesis) but overload damages it → the objective is not complete rest (deleterious) but optimized and progressive loading → maintain activity within pain limits (pain ≤ 4/10 during and return to normal within 24 hours)
• Acute phase — reducing the irritant load: Identify and reduce (but not eliminate) aggravating activities → substitute with low-impact activities for the tendon (cycling + swimming + unloaded exercises) + ice after activity (pain-relieving effect) + paracetamol or short-term NSAIDs (symptomatic relief) + brace or splint if necessary
• Eccentric exercises (cornerstone of chronic tendinopathy treatment): muscular contraction during tendon lengthening → Alfredson's program for the Achilles tendon (200 repetitions/day × 3 sets of calf raises → slow descent over 3 counts) + Stanish's program + pain reduction from 60–90 % to 3 months in Achilles and patellar tendinopathies + mechanism: stimulation of collagen synthesis + fiber reorganization + reduction of neovascularization
• Isometric exercises (acute phase + reactive tendinopathies): Intense static contraction (70–80 % of maximal force) × 5 repetitions × 45 seconds → immediate pain reduction (cortical analogue effect) + no dynamic load on tendon → useful in the initial painful phase
• Isotonic and plyometric exercises (progressive loading phase): Progression from isometric → slow isotonic → fast isotonic → plyometric → sport-specific activity → return to sport → progression must adhere to the absence of residual pain (> 24 hours) before advancing to the next stage
• Corticosteroid injections short-term analgesic effect (4–8 weeks) + but does not alter long-term progression + repeated infiltrations (≥ 3) weaken collagen + increase rupture risk → limit to a maximum of 1–2 infiltrations over time + do not infiltrate the body of the Achilles tendon (rupture risk) + associated bursitis may benefit from targeted infiltration
• Platelet-rich plasma (PRP): Platelet-rich plasma (PRP) injection (growth factors + PDGF + TGF-β + VEGF + IGF) → stimulation of tendon regeneration + randomized studies: mixed results but positive trend for chronic refractory tendinopathies (epicondylitis + Achilles) + less risk than corticosteroids
• Extracorporeal Shockwave Therapy (ESWT) Acoustic microtrauma → stimulation of vascularization + collagen synthesis + desensitization of nociceptors → proven efficacy in calcific tendinopathies of the shoulder + epicondylitis + plantar fasciitis + 3–5 sessions weekly

Consult at Clinique Omicron

Clinique Omicron's physician associates and nurse practitioners (NPs) diagnose tendinopathies through clinical examination (specific tests based on location), prescribe appropriate imaging assessments (ultrasound + MRI if rupture is suspected), initiate load management, and refer patients to physiotherapy for eccentric exercise and progressive loading programs, prescribe short-term NSAIDs for symptomatic relief, assess the indication for corticosteroid injections or PRP based on the clinical presentation, and screen for systemic contributing factors (diabetes + dyslipidemia + fluoroquinolones). Consultations are available at several service points in Quebec and via telemedicine. To book an appointment, visit cliniqueomicron.ca.

The content of this page is for informational purposes only and does not substitute medical advice from a doctor, physical therapist, or sports physician. A complete tendon rupture (particularly the Achilles tendon) is an orthopedic emergency. Repeated corticosteroid injections into a tendon weaken collagen and increase the risk of rupture—limit to a maximum of 1-2 injections over the course of tendinopathy.