A 59-year-old woman presented with a 2-month history of right shoulder pain and swelling. The patient reported a traumatic fall 9 months prior. Physical examination revealed a limited and painful active and passive range of motion of the right shoulder.
Plain radiograph of the right shoulder showed significant destruction, deformity, and cranial subluxation of the humeral head. There was also evidence of osteolysis of the acromial end of the clavicle. Intra-articular calcifications were apparent as well (Figure 1a). A shoulder radiograph performed one year earlier did not reveal any of these findings (Figure 1b).
The computed tomography (CT) scan demonstrated extensive destruction of the humeral head, glenoid, and coracoid process. Osteolysis of the inferior surface of the acromion and the lateral end of the clavicle was visible (Figures 2a and 2b). There was a large joint effusion, with extensive areas of synovial proliferation (Figures 3a, 3b and 3c) associated with capsular calcifications and intra-articular amorphous calcium deposition (Figures 2a and 2b). Signs of massive rotator cuff tear were present, with marked atrophy and fatty infiltration of the corresponding muscle (Figure 3c), with consequent migration of the remaining humeral head and reduction of the subacromial space.
Background
Milwaukee shoulder is a rare condition characterised by massive destruction of the shoulder joint due to intra-articular deposition of calcium phosphate crystals [1]. The deposition of these crystals within the joint space triggers the release of lysosomal enzymes, which then degrade the bones and surrounding periarticular structures, including the rotator cuff tendons [2,3].
Clinical Perspective
The disease typically affects elderly women and presents with progressive shoulder pain, joint swelling, and limited range of motion [4].
The insidious onset and progressive nature of the disease often lead to a delayed diagnosis and treatment. Furthermore, symptoms are frequently disproportionate to the advanced state of bone destruction [5].
While unilateral shoulder joint involvement, typically in the dominant side, is more common, Milwaukee shoulder can also present bilaterally in some cases [2]. Predisposing factors include recent trauma, joint overuse, dialysis, and hyperparathyroidism [6].
Imaging Perspective
Since the clinical presentation of Milwaukee shoulder is non-specific and its symptoms overlap with those of other conditions, imaging techniques are crucial for diagnosing and ruling out other potential causes [7].
Plain radiographs often reveal extensive joint space narrowing, subchondral bone destruction with partial bony collapse of the humeral head, intra and peri-articular calcifications, and subchondral sclerosis with cyst formation. The bone destruction can also extend to the acromion, the coracoid process, and the distal clavicle. Pseudoarthrosis involving the humeral head, coracoid, and acromion is common [2,6].
CT is useful for a more detailed evaluation of bone destruction and for pre-operative planning. Magnetic resonance imaging (MRI) provides a better evaluation of soft-tissue-associated changes, such as rotator cuff tears and synovitis, and offers a detailed assessment of cartilage damage [6].
Large joint effusions are frequently observed, with extension to subdeltoid and subacromial regions. There is also a strong association with massive rotator cuff tears [6,8].
A definitive diagnosis is confirmed by detecting hydroxyapatite crystals in synovial fluid, using alizarin red staining [2,5].
Outcome
The treatment is focused on symptomatic relief, with nonsteroidal anti-inflammatory drugs, corticosteroid injections, and physical therapy being the most common conservative strategies. In cases of severe joint destruction or advanced degenerative changes, surgical interventions may be necessary [2].
Take Home Message / Teaching Points
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Milwaukee shoulder
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In this patient’s shoulder X-ray and CT images, there is marked bone destruction and narrowing of the right shoulder joint space. There is partial collapse or defect of the humeral head, along with clearly irregular bony margins. Calcifications can be seen within and around the joint, accompanied by localized soft tissue swelling. Some images also indicate varying degrees of erosion in the acromion, coracoid process, and the distal clavicle. A large joint effusion is evident, which may involve the rotator cuff structures (suggesting a large-scale rotator cuff tear or severe degeneration).
Caused by the deposition of calcium phosphate salts (hydroxyapatite), leading to destructive joint changes, commonly occurring in elderly women. It often presents with progressive shoulder pain, marked restriction of motion, and large joint effusions. Imaging typically shows severe joint destruction and soft tissue calcification.
Associated with aging or long-term rotator cuff tears, leading to degenerative changes in the joint. It may also show joint space narrowing, subchondral bone destruction, and osteophytes. However, the calcification and soft tissue damage are usually more “regular” and often less aggressive than those seen in Milwaukee shoulder.
Acute or subacute infection can cause bony erosions and damage to the joint space. However, patients often present with acute inflammatory signs and systemic symptoms (such as fever and elevated white blood cell count). In the absence of corresponding laboratory or clinical findings, infectious arthritis is less likely.
Taking into account the patient’s age, sex, gradual progression of shoulder pain and restricted motion, and imaging evidence of significant joint destruction, extensive calcification, and a large joint effusion, these findings are most consistent with Milwaukee shoulder. For further confirmation, an arthrocentesis can be performed with appropriate staining (e.g., Alizarin red for detecting apatite crystals) to definitively confirm the diagnosis.
4.1 Conservative Treatment and Medications
Initially, symptom relief is the main focus: Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) can reduce pain and inflammation; if pain is severe, intra-articular corticosteroid injections may be considered. If there is extensive rotator cuff damage, surgical repair or joint replacement should be evaluated based on functional demands and pain severity.
4.2 Physical Therapy and Rehabilitation
Key elements of rehabilitation include pain control and maintaining joint mobility. During the acute inflammatory phase, rest, immobilization, and pain-relieving physiotherapy (such as cold or heat therapy) are recommended to avoid aggravating the shoulder. After inflammation subsides, a progressive exercise program under the guidance of a professional therapist is essential.
Below is a simplified example following the FITT-VP principle (Frequency, Intensity, Time, Type, Progression, and Volume):
Throughout the rehabilitation process, pain, swelling, or other discomfort should be closely monitored. If symptoms worsen significantly, seek medical attention promptly and adjust the training intensity and methods accordingly.
This report is based on the current data and imaging findings and provides a reference analysis. It does not replace in-person consultation or the advice of a qualified physician. Patients should combine the clinical situation with specialized medical advice to formulate and adjust final treatment and rehabilitation plans.
Milwaukee shoulder
