Milwaukee shoulder

Milwaukee shoulder refers to a destructive shoulder arthropathy due to deposition of hydroxyapatite crystals, and identification of these crystals in synovial fluid is the cornerstone of diagnosis.

Epidemiology

Milwaukee shoulder frequently affects older women, often with a history of trauma to the region. 

Clinical presentation

Symptoms are usually comparatively mild, despite rapid and marked progression of radiographic features. 

Radiographic features

Plain radiograph

Radiographic findings are striking and almost resembles a neuropathic joint, with advanced articular surface destruction with intra-articular loose bodies, subchondral sclerosis, soft tissue swelling and rotator cuff disruption. Cases often demonstrate superior subluxation of the humeral head in relation to the glenoid fossa ⁴. The superior subluxation can also result in a pseudoarthrosis with the distal clavicle and/or acromion ⁷.

MRI

MRI findings mirror those of the plain radiographs and include: 

• large shoulder joint effusion
• complete rotator cuff tear
• narrowing of the glenohumeral joint
• thinning of cartilage
• destruction of subchondral bone

Treatment and prognosis

No specific treatment is available, only supportive treatment for symptom relief ³. 

History and etymology

Regius Professor of Surgery, Dr Robert Adams (1791 -1875) was an Irish surgeon who first described this pathology in his own textbook published in 1857 ⁵.
In 1981, a group of Milwaukee based researchers encountered four cases of rotator cuff loss, shoulder arthropathy and joint effusions containing calcium phosphate crystals and hence coined the term  'Milwaukee shoulder' ⁶. 

Differential diagnosis

General imaging differential considerations include

• Charcot joint
• vanishing bone disease
• advanced secondary osteoarthritis
  • previous trauma
  • previous septic arthritis