Hydroxyapatite deposition disease (calcific periarthritis)
Hydroxyapatite (basic calcium phosphate) deposition disease is a crystal arthropathy distinct from gout and CPPD that most often causes acute calcific periarthritis of the rotator cuff and, rarely, the destructive Milwaukee shoulder syndrome in older women. Because hydroxyapatite crystals are not birefringent, diagnosis rests on periarticular calcification on radiograph and exclusion of septic arthritis and the other crystal arthropathies rather than on routine polarized light microscopy.
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What this article covers
- Overview
A distinct crystal arthropathy: hydroxyapatite deposition disease, also called basic calcium phosphate (BCP) crystal deposition disease, results from deposition of hydroxyapatite crystals in…
- Epidemiology
Age-related: BCP deposition in periarticular tendons, ligaments, and articular cartilage becomes more prevalent with advancing age.
- Risk factors
Advancing age: the single strongest risk factor; BCP deposition targets periarticular tendons, ligaments, and articular cartilage in older adults.
- Pathophysiology
Crystal formation in degenerating tissue: hydroxyapatite crystals form within periarticular tendon, ligament, and cartilage that has undergone age-related or mechanical degeneration, most classically the supraspinatus tendon.
- Clinical features
Acute calcific periarthritis/tendinitis attack: abrupt onset of severe periarticular pain and swelling, most commonly the rotator cuff (especially the supraspinatus tendon); its intensity and speed…
- Differential diagnosis
Septic arthritis: the most dangerous mimic; fever, warmth, and erythema with constitutional symptoms, synovial leukocyte count often 50,000/µL or higher with neutrophil predominance, and a positive…
- Diagnosis
How the diagnosis is established: no formal validated criteria set exists; the diagnosis is clinical, based on a typical periarticular pain pattern (acute calcific periarthritis/tendinitis) or the…
- Management
First, exclude and treat septic arthritis if suspected: if aspiration raises concern for infection (leukocyte count 50,000/µL or higher, positive Gram stain, or high clinical suspicion), manage…
- Complications
Progressive rotator cuff and glenohumeral joint destruction: the natural course of untreated or advanced Milwaukee shoulder, causing irreversible loss of shoulder function that ultimately requires arthroplasty.
- Prognosis
Acute calcific periarthritis/tendinitis generally responds to conservative therapy: most attacks improve with NSAIDs and/or corticosteroid injection, though symptoms can recur, which is why…
- Prevention
Limit corticosteroid injection frequency to avoid iatrogenic injury: no more than 2 to 3 intrabursal or intra-articular injections per year at the same site, and no more than 3 to 4 injections per…
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Related articles
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- Pseudogout
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- Septic arthritis
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- Bursitis
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- Rheumatoid arthritis
Rheumatoid arthritis is a chronic systemic autoimmune disease causing symmetric small-joint polyarthritis of the hands and feet that spares the distal interphalangeal joints, with morning stiffness over an hour. Diagnosis combines the ACR/EULAR classification criteria with rheumatoid factor, anti-CCP antibody, and radiographs. Treat-to-target management anchors on methotrexate, escalating to a biologic or targeted synthetic disease-modifying antirheumatic drug when remission is not reached.
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