Calcific tendinitis

Calcific tendinitis is a self limiting condition due to deposition of calcium hydroxyapatite within tendons, usually of the rotator cuff.

Demographics and clinical presentation

Typically this condition affects middle aged patients between the ages of 30 and 60, with a slight predilection for women ².

The condition passes through four stages ²:

1. pre-calcific
   • asymptomatic
   • fibrocartilagenous metaplasia (see below)
2. calcific or formative
   • symptoms are variable from none to pain on movement
3. resorptive
   • most symptomatic
   • pain due to extravasation of calcium hydroxyapatite into adjacent tissues, especially subacromial bursa
   • pain typically lasts 2 weeks
4. post-calcific
   • variable symptomatology
   • some restriction of movement common
   • may last months

Pathology 

Calcific tendonitis results from the deposition of calcium hydroxyapatite within the substance of a tendon, and is thought to be due to decreased oxygen tension, leading to fibrocartilagenous metaplasia and secondary mineralization ¹.

Location

This condition most frequently affects the rotator cuff of the shoulder ¹.

• supraspinatus - 80%
• infraspinatus - 15%
• subscapularis - 5%
• periarticular soft tissues in addition to tendons
• ligaments
• capsule
• bursae

Radiographic features

Plain film

• calcific deposits are usually visualised as homogeneous hyperdensity with variable morphology, but typically globular / amorphous with poor margins.

MRI

• T1 -
  • hypo intense homogeneous signal
  • adjacent tendon may be thickened
  • some enhancement surrounding deposit may be seen
• T2 -
  • hypo intense calcium deposits
  • hyper intense signal may be present peripherally due to oedema
  • hyper intense subacromial-subdeltoid bursal fluid
• T2* - calcifications may bloom

Treatment and prognosis

Controversial and difficult to measure due to the inherent variability of the symptoms and the self limiting nature of the disease. Potential treatments include  ²:

• oral analgesia / anti-inflammatory medication
• subacromial local anesthetic / steroid injection
• aspiration of mineralised material
• ultrasound therapy

Differential diagnosis

• incidental calcification: seen in 2.5-20% of 'normal' healthy shoulders ^1-2
• degenerative calcification
  • seen in previously torn tendons
  • generally smaller
  • slightly older individuals
• loose bodies
  • associated chondral defect
  • associated secondary osteoarthritis