tendonitis (tendon injury)

Etiology

• trauma
  • strain
    • excessive tensile forces on musculo-tendinous junction resulting in stretching & tearing
    • risk factors: lack of flexibility, insufficient warm-up, local corticosteroid injection, fatigue, deconditioning, recent injury
  • contusion
    • a result of high velocity compressive forces
    • the more contracted the muscle at the time of injury, the worse the injury
• overuse (tendinosis)
  • repetitive microtrauma exceeds the capacity of repair processes & accumulates over time
  • tendon injuries are the most common overuse conditions encountered in sports injuries
  • the tendon body & the site of bony insertion (insertional tendonitis) are the 2 most common sites of overuse injury
  • activities that require repetitive overhead movement
• inflammatory arthropathy unlikely if isolated tendon involvement
  • rheumatoid arthritis (RA)
  • systemic lupus erythematosus (SLE)
• risk factors
  • extrinsic risk factors
    • training
    • play or work surfaces
    • equipment or footwear
    • biomechanics of sport or activity generally determines the tendon(s) at risk
  • intrinsic risk factors
    • anatomic malalignment
    • leg length discrepancy
    • muscle imbalance
    • muscle weakness
    • inflexibility
    • excessive joint laxity
    • associated diseases
      • rheumatoid arthritis
      • hypothyroidism
      • diabetes mellitus
    • previous injury improperly or incompletely treated

Clinical manifestations

• general
  • pain on active range of motion
    • passive range of motion is NOT painful
  • range of motion is preserved unless limited by contracture or calcification
  • may be elicited by palpation of the involved tendon(s)
• traumatic tendonitis
  • an audible pop or snap indicates significant muscle-tendon tearing
  • initially there is frequently very little pain & disability
  • swelling, pain & disability progress over several hours & are maximal the day following the injury
  • weakness without reproduction of pain indicates nerve injury
  • mild of 1st degree strain of muscle-tendon unit
    • 'pulled muscle'
    • overstretching of muscle-tendon unit
    • no palpable defect
    • mild inflammatory changes
  • moderate or 2nd degree strain of muscle-tendon unit
    • 10-90% tearing of muscle-tendon unit
    • palpable defect
    • significant inflammatory changes
  • severe or 3rd degree strain of muscle-tendon unit
    • complete rupture of muscle-tendon unit
    • large palpable defect
    • proximal contracted ball of torn tissue
• overuse tendonitis
  • grade 1 (symptoms present for < 2 weeks)
    • soreness after the aggravating activity
    • pain resolve quickly, generally within hours
    • no functional impairment
  • grade 2 (symptoms persist for 2-3 weeks)
    • pain during the later phase of the aggravating activity
    • pain persists after the activity is complete
    • no functional impairment
  • grade 3 (symptoms present for 3-4 weeks)
    • pain during most of the aggravating activity continuing after the activity is complete
    • performance is affected
  • grade 4 (symptoms present for > 4 weeks)
    • pain is continuous, before, during & after the activity
    • activities of daily living frequently affected
  • palpation of involved tendon frequently reproduces patient's pain
  • resisted active contraction of the involved tendon generally reproduces the patient's pain

Laboratory

• coagulation workup if indicated
• rheumatologic work-up if indicated
  • erythrocyte sedimentation rate (ESR)
  • C-reactive protein (CRP)
  • antinuclear antibody (ANA)
  • rheumatoid factor (RF)

Radiology

• radiographs generally not necessary when diagnosis is tendonitis
• radiographs should be obtained if
  • myositis ossificans suspected
  • stress fracture suspected

Complications

• bursitis may result from the proximity of a bursa to the inflamed tendon
• compartment syndrome may occur with any severe injury

Differential diagnosis

• nerve injury with radicular pattern may mimic traumatic or overuse tendonitis
• distal nerve compression may present with proximal pain
• connective tissue disease may present as overuse tendonitis or may be complicated by acute tendon rupture
• steroid abuse-induced tendon rupture, especially at uncommon site
• myositis ossificans may occur post muscle-tendon injury
• coagulation disorder: i.e. hemophilia
• stress fracture

Management

• R: rest
• I: ice
• C: compression
• E: elevation
• D: non-steroidal anti-inflammatory Drugs

• Jones dressing: 2 alternating layers of cast padding & ACE wrap applied distal to proximal
• painless range of motion
• strengthening exercises after swelling has subsided & range of motion is pain free
• glucocorticoid injection may improve outcome over the short term, but long-term benefits are doubtful
• follow-up
  • re-evaluate grade 2 & 3 traumatic injuries in 7-10 days
  • re-evaluate grades 2-4 overuse tendonitis every 2-4 weeks
  • do not continue NSAIDs to permit return to activity

More general terms

• enthesopathy (enthesitis)
• inflammation

More specific terms

• Achilles tendonitis
• biceps tendonitis (bicipial tendonitis)
• calcific tendonitis
• coxa saltans; snapping hip; iliopsoas tendonitis; dancer's hip
• gluteal tendonitis
• insertional tendonitis
• intersection syndrome
• quadriceps tendonitis
• rotator cuff tendonitis; impingement syndrome; painful arc syndrome; subacromial pain syndrome
• supraspinatus tendonitis
• tendinosis

Additional terms

• tendon