Diseases of Tendons and Fascia

Tendon & Fascia Basics - The Body's Tethers

• Tendons: Dense connective tissue; connect muscle to bone; transmit tensile forces.
  • Structure: Parallel collagen fibers (primarily Type I), fibroblasts (tenocytes), proteoglycans.
  • Blood Supply: Limited, mainly at musculotendinous & osteotendinous junctions.
• Fascia: Sheets of connective tissue; envelop muscles, organs, vessels.
  • Types: Superficial, deep, visceral.
  • Function: Support, compartmentalization, force transmission.

⭐ Tendons are predominantly composed of Type I collagen, providing high tensile strength.

• Innervation: Sensory nerves for proprioception and nociception (pain).

General Tendinopathies - Strained Strands Saga

• Tendinopathy: Umbrella term for tendon disorders, often from overuse or repetitive microtrauma.

• Pathogenesis: Imbalance between tendon matrix degeneration & synthesis.

  • Failed healing response leads to chronic changes.

• Spectrum of Tendon Injury:

  • Reactive Tendinopathy: Acute overload, non-inflammatory proliferative response, tendon thickening. Reversible.
  • Tendon Dysrepair: Attempted healing, ↑ proteoglycans, collagen disorganization, neurovascular ingrowth. Possible reversibility.
  • Degenerative Tendinopathy (Tendinosis): Chronic, cell death, matrix breakdown, extensive disorganization, minimal inflammation. Less reversible.

⭐ Tendinosis is a degenerative process characterized by collagen disorganization, increased ground substance, and neovascularization, distinct from primarily inflammatory tendinitis.

• Clinical: Pain with activity, localized tenderness, palpable nodule (in tendinosis).
• Histology:
  • Tendinitis: Acute inflammation (neutrophils, macrophages). Rare in chronic cases.
  • Tendinosis: Collagen fiber disarray (Type III > Type I), ↑ ground substance (mucoid degeneration), neovascularization, hypercellularity (tenocytes, myofibroblasts), no significant inflammation.

• Common sites: Achilles, patellar, rotator cuff, elbow (epicondylitis).

Fascial Pathologies - Fascia's Fierce Fight

• Plantar Fasciitis:
  • Etiology: Repetitive microtrauma (e.g., running), obesity, improper footwear.
  • Pathology: Plantar fascia degeneration (calcaneal origin); fibroblastic proliferation, collagen disarray.
  • Clinical: Heel pain (worse AM/after rest); medial calcaneal tenderness.
• Dupuytren's Contracture (Palmar Fibromatosis):
  • Pathogenesis: Palmar fascia thickens: nodules → cords → contractures.

  ⭐ Dupuytren's contracture is characterized by palmar fascial thickening due to proliferation of myofibroblasts and altered collagen (increased Type III).

  • Clinical: Painless palmar nodules, progressive flexion contractures (typically 4th & 5th digits, MCP/PIP). Positive "tabletop test".
  • Associations: Northern European, alcohol, smoking, DM, epilepsy. 📌 "Dupuytren's: Digits Draw Down"
• Ledderhose Disease (Plantar Fibromatosis):
  • Plantar foot nodules; like Dupuytren's but in feet. May be painful.

Specific Tendon Syndromes - Spotlight on Sorrows

• Achilles Tendinopathy: Overuse; pain posterior heel/calf. ↑Risk: fluoroquinolones. Degeneration.
• Rotator Cuff Tears: Supraspinatus (abduction initiation) common. Pain on abduction/overhead. Drop arm test +.
  • 
• Lateral Epicondylitis (Tennis Elbow): Extensor Carpi Radialis Brevis origin. Pain lateral elbow, wrist extension.
• Medial Epicondylitis (Golfer's Elbow): Common flexor-pronator origin. Pain medial elbow, wrist flexion.
• De Quervain's Tenosynovitis: Abductor Pollicis Longus (APL) & Extensor Pollicis Brevis (EPB) tendons (1st dorsal compartment).

  ⭐ Finkelstein's test (passive ulnar deviation of wrist, thumb flexed in palm) is pathognomonic for De Quervain's tenosynovitis.

• Ganglion Cyst: Mucin-filled synovial cyst (often wrist). Transilluminates. Usually asymptomatic.

High‑Yield Points - ⚡ Biggest Takeaways

• Tendinopathy is primarily degenerative due to failed healing, not inflammatory.
• De Quervain's tenosynovitis affects APL & EPB tendons; Finkelstein test is key.
• Trigger finger (stenosing tenosynovitis): A1 pulley thickening causes digit locking.
• Dupuytren's contracture: Palmar fibromatosis (nodules, cords); common in Northern Europeans, associated with diabetes, alcoholism.
• Ganglion cyst: Mucinous degeneration near joints or tendon sheaths; transilluminates.
• Achilles tendinopathy: Common overuse injury; pain at mid-portion or calcaneal insertion.