Pathology & Diagnosis

• What is tendinopathy?

  • Painful and structural compromise of the tendon, leading to loss of function
  • Non-specific but defines clinical presentation
  • Can include:
  • tendon structure
  • paratenon/sheath
  • other local structures – fat pads, bursa
  • remote involvement eg CNS
• Theories on Tendinopathy Pathogenesis:

  • Mechanical – overload of cells leading to failed healing and matrix breakdown
  • Inflammation – cells and mediators and overlapping with mechanical theory
  • Degenerative - oxidative/apoptosis
  • Neurogenic mediated
  • Continuum – acute to failed healing to degenerative
• Tendinopathy: structural changes - what changes:

  • Cell activity and populations
  • Matrix alterations – collagen 1 to collagen 3
  • Changes to non-collagenous matrix – Proteoglycans and Glycosaminoglycans
  • Attempt at repair – neovascular and nerve ingrowth
• Tendinopathy: structural changes - common features:

  • Hypercellularity zones
  • Apoptosis zones - zones where cells have died
  • Matrix breakdown and degeneration
  • Neovascularisation/neoinnervation
• Excess cumulative load leads to:

  1. Early inflammation – not symptomatic, under the threshold
  2. Macrophages/mast cells – cytokine signalling
  3. Tenocyte overactivity – rounding of cell
  4. Proteoglycan over expression
  5. Neuropeptides secreted
  6. Matrix breakdown – collagen 1 and 3
  7. Tenocyte proliferation/apoptosis
  8. Neoinnervation/neovascularisation
  9. Chronic – central sensitisation?

  
• Where does the pain come from?

  • Localised, never spreads
  • Neoinnervation in paratenon (Alfredson, Andersson 2007)
  • Tenocyte over-activity leads to release of:
  • Neurotransmitters and cytokines and proteoglycans
  • CNS - Rio et al 2013 The Pain of Tendinopathy: Physiological or Pathophysiological? Sports Med
• Subjective assessment of Tendinopathy:

  • Location - Precise and localised
  • Pain behaviour – aggs/ease/24hr
  • History of onset - sudden/gradual
  • Risk factors – can we modify?
  • Bio-psychosocial considerations - fear avoidance = control deficits
• Objective assessment of Tendinopathy:

  • Palpation - Thickening, swelling, pain
  • Load the muscle-tendon unit - Stretch? Or compress? Or both? Depends on location
  • Test the Stretch-Shortening Cycle - Test the spring
  • Function - Relevant to activity
  • Differential diagnosis
  • Imaging - Optional but needed if non-responder
• Radiological Investigations:

  • Ultrasound
  • Structural detail and matrix breakdown
  • Can see neovascularisation
  • Real-time assessment
  • MRI
  • Less detail but useful to exclude other pathology
  • Ultrasound Tissue Characterisation
  • Very new and not yet mainstream – semi-quantifies structure