Hydroxyapatite Deposition Disease 

Rheumatology Icon

Overview

Hydroxyapatite Deposition Disease (HADD) is a crystal-induced tendinopathy caused by the deposition of hydroxyapatite (HA) crystals, typically in periarticular soft tissues, especially tendons and bursae. The shoulder (supraspinatus tendon) is most commonly affected. It often presents between ages 30–60, more frequently in women. While often asymptomatic, it can cause acute pain and functional limitation during resorptive phases.

Definition

Hydroxyapatite (HA): A calcium phosphate crystal naturally found in bone but pathologically deposited in soft tissues.
HADD: Disease resulting from abnormal deposition of HA crystals in tendons or bursae, leading to pain and inflammation.
Calcific tendinitis: Clinical term describing symptomatic HADD, often in the shoulder.
Periarticular: Refers to structures surrounding a joint (e.g. tendons, bursae).

Anatomy and Physiology

  • The rotator cuff (supraspinatus, infraspinatus, subscapularis, teres minor) stabilizes the glenohumeral joint.
  • The subacromial-subdeltoid bursa reduces friction between the rotator cuff and overlying structures.
  • Tendons are poorly vascularized, especially near insertion zones (enthesis), which may predispose to crystal deposition.

Aetiology and Risk Factors

Aetiology

  • Unknown in most cases (idiopathic)
  • Possibly due to cell necrosis, hypoxia, or local mechanical stress causing crystal precipitation
  • May be related to disordered healing of tendon microtears

Risk Factors

  • Age 30–60
  • Female sex
  • Diabetes mellitus
  • Hypothyroidism
  • Repetitive overuse or trauma (especially shoulder)
  • Chronic renal disease (rare)

Remember

HADD = middle-aged women + shoulder pain + calcification.

Pathophysiology

  • Pre-calcific stage: Fibrocartilaginous metaplasia occurs in tendon → prone to mineralization
  • Calcific stage:
    • Formative phase: Deposition of HA crystals
    • Resorptive phase: Inflammatory reaction with macrophage and giant cell infiltration → severe pain
  • Post-calcific stage: Remodeling and healing with tendon reconstitution

Symptoms typically arise in the resorptive phase due to intense local inflammation.

Clinical Manifestations

  • Often asymptomatic during formative phase
  • Acute calcific tendinitis
    • Sudden, severe shoulder pain, often nocturnal
    • Limited active ROM, especially abduction and external rotation
    • Pain on palpation over greater tuberosity
  • Chronic phase
    • Dull ache
    • Stiffness and impingement signs
  • Bursitis or tenosynovitis if crystals rupture into adjacent structures
    • Less common sites: hip, elbow, wrist, knee

Shoulder pain + calcification on X-ray + intact ROM = HADD.

Diagnosis

No formal criteria, diagnosis is clinical + radiologic

  • X-ray
    • Homogeneous, dense calcific deposit in tendon (e.g. supraspinatus)
    • Location: 1–2 cm from insertion
  • Ultrasound
    • Hyperechoic calcification with posterior shadowing
    • May show signs of bursitis or tendon rupture
  • MRI
    • Shows soft tissue edema, inflammation, may mimic rotator cuff tear
  • Aspiration (rarely done)
    • HA crystals are non-birefringent, not visualized on polarised microscopy
    • Can stain with Alizarin red (calcium-binding dye)

Crystal Arthropathy Clinical Comparison Table

FeatureGoutPseudogout (CPPD)BCP / Milwaukee ShoulderHADD (Hydroxyapatite)
Typical Age30–50 (M > F)>60>70 (F > M)30–60 (F > M)
Crystal Type & ShapeMonosodium urate, needleCalcium pyrophosphate, rhomboidBCP (hydroxyapatite), amorphousHydroxyapatite, amorphous
BirefringenceStrongly negativeWeakly positiveNoneNone
Common Joint Involved1st MTP, midfoot, ankleKnee, wristShoulder (glenohumeral joint)Shoulder (supraspinatus tendon)
Synovial Fluid WBCHigh (2,000–50,000+)Moderate (2,000–50,000)Low (<2,000), non-inflammatoryNormal to mildly elevated

Differential diagnoses

  • Rotator cuff tear
  • Subacromial bursitis
  • Adhesive capsulitis
  • Septic arthritis (if systemic signs present)
  • Gout/pseudogout (if intra-articular)

Remember

HADD calcific deposits are dense, homogeneous on X-ray and non-birefringent.

Remember

If unsure on ultrasound, confirm with X-ray – classic finding is curvilinear or oval dense calcification near tendon insertion.

Treatment

Acute phase

  • NSAIDs (first-line)
  • Rest and ice
  • Physiotherapy (after acute pain subsides)
  • Local corticosteroid injection if significant inflammation
  • Needle lavage/barbotage (ultrasound-guided): break up and aspirate calcification
  • Ultrasound therapy for pain control
  • Surgery (arthroscopic removal) if refractory after 6–12 months

Chronic phase

  • Ongoing physiotherapy and ROM exercises
  • Treat contributing factors (e.g. diabetes, thyroid dysfunction)

Complications and Prognosis

Complications

  • Rotator cuff tear
  • Adhesive capsulitis
  • Chronic pain or impingement syndrome
  • Bursal rupture or inflammation

Prognosis

  • Excellent prognosis in most with conservative management
  • Most resolve spontaneously within 1–3 weeks during resorptive phase

Poor Prognostic Factors

  • Large deposits
  • Chronic symptoms >6 months
  • Recurrent episodes
  • Poor compliance with rehab

References

  1. Harvie P, Pollard TC, Carr AJ. Calcific tendinitis: natural history and association with endocrine disorders. J Shoulder Elbow Surg. 2007;16(2):169–173.
  2. Uhthoff HK, Loehr JW. Calcific tendinopathy of the rotator cuff: pathogenesis, diagnosis, and management. J Am Acad Orthop Surg. 1997;5(4):183–191.
  3. Chianca V, et al. Calcific tendinopathy: imaging findings and therapeutic options. Radiol Med. 2020;125(5):431–447.
  4. Jiménez-Martín A, et al. Calcific tendinopathy of the shoulder: clinical and radiological analysis of 100 patients. Clin Rheumatol. 2022;41(3):821–828.
  5. de Witte PB, et al. Therapeutic options for calcific tendinitis of the rotator cuff: a state-of-the-art review. Br J Sports Med. 2016;50(15):884–890.

Related Content

Discussion

0 Comments
Most Voted
Newest Oldest
Inline Feedbacks
View all comments

Table Of Contents

The AH Community Platform is coming
Get access to member features
Early access launches soon
Armando hasudungan brain logo
Armando Hasudungan
Medical & Biology Tutorials
© 2025 Visualising Medicine. All rights reserved.
Become a member to access note taking
Orangise your medical learning
This is just one of the many AH community member perks
Become a member to access quizzes
Strengthen your medical knowledge
This is just one of the many AH community member perks
0
Would love your thoughts, please comment.x
()
x