Comprehensive Review of Calcific Tendinopathy of the Supraspinatus: Pathophysiology, Imaging, Diagnosis, and Advanced Treatment Strategies
Abstract
Calcific tendinopathy of the supraspinatus is a common cause of shoulder pain, particularly among middle-aged adults. This article provides a comprehensive review of the pathophysiology, epidemiology, clinical presentation, imaging findings, differential diagnosis, and evidence-based management options. The integration of radiological imaging and updated treatment modalities—including ultrasound-guided procedures, shockwave therapy, and arthroscopic removal—are discussed in the context of current international guidelines.
1. Pathophysiology
Calcific tendinopathy (CT) of the supraspinatus is a multifactorial, cell-mediated process characterised by the deposition of calcium hydroxyapatite crystals within the tendon substance. Historically regarded as a degenerative condition, modern research identifies it as an active, cell-regulated process involving tenocytes and fibrocartilaginous metaplasia.
The disease progresses through three major stages:
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Formative Phase:
Tenocytes undergo metaplastic transformation into chondrocyte-like cells, leading to calcium deposition within matrix vesicles. This process is believed to be driven by local hypoxia, mechanical stress, and vascular compromise. -
Resting Phase:
The calcific deposits remain stable, often asymptomatic during this stage. -
Resorptive Phase:
Vascular infiltration and macrophage-mediated phagocytosis occur, producing acute inflammatory pain and local oedema. This phase corresponds clinically with severe pain and radiographically with the disappearance of dense calcific foci.
2. Epidemiology
Calcific tendinopathy affects approximately 2.7–20% of the general population, with a higher incidence in females aged 30–60 years. The supraspinatus tendon is involved in 65–70% of cases, followed by the infraspinatus and subscapularis tendons.
Risk factors include:
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Repetitive overhead activity (e.g., swimming, tennis)
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Endocrine disorders (notably diabetes mellitus and thyroid dysfunction)
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Genetic predisposition involving collagen type I gene polymorphisms
Occupational associations are significant, particularly among manual labourers and office workers with poor posture contributing to chronic microtrauma.
3. Clinical Presentation
Symptoms vary according to the disease stage.
Typical features include:
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Sudden or chronic shoulder pain localised to the anterolateral aspect
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Night pain preventing lying on the affected shoulder
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Limited range of motion, particularly abduction between 60–120° (“painful arc”)
On examination, tenderness over the greater tuberosity and reduced abduction strength are typical. The Neer impingement and Hawkins-Kennedy tests often yield positive results.
4. Imaging Features
Radiological evaluation remains crucial for diagnosis and treatment planning.
4.1 Plain Radiography
Figure 2. Axial view of the left shoulder demonstrating a homogeneous high-density lesion within the distal supraspinatus tendon fibres near the insertion.
Figure 3. Left shoulder anteroposterior radiograph showing a round or oval calcific focus with well-defined margins.
Figure 4. Follow-up AP radiograph of the left shoulder demonstrating reduced size and blurred margins of the calcific deposit, suggesting the resorptive phase.
Gartner and Heyer Classification (1981):
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Type I: Well-defined, dense deposits (formative phase)
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Type II: Partially defined, translucent deposits
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Type III: Poorly defined, cloudy deposits (resorptive phase)
4.2 Ultrasonography (USG)
High sensitivity (≈90%) and allows real-time assessment.
Features include:
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Hyperechoic deposits with posterior acoustic shadowing
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Absence of vascularity during formative phase; increased flow on Doppler during resorption
4.3 Magnetic Resonance Imaging (MRI)
MRI is particularly useful for pre-operative evaluation.
Figure 6. Coronal PD fat-saturated image demonstrating a low-signal calcific deposit surrounded by high-signal oedematous changes.
Figure 8. Axial PD fat-saturated image revealing rupture of the calcific deposit into the subacromial bursa.
5. Differential Diagnosis
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Rotator cuff tear
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Subacromial bursitis
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Tendon xanthoma
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Hydroxyapatite deposition disease (HADD) involving other tendons
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Myositis ossificans
6. Diagnosis
A combination of clinical evaluation and imaging provides diagnostic confirmation.
Ultrasound-guided aspiration or lavage may be diagnostic and therapeutic simultaneously.
Laboratory tests are typically normal; however, metabolic screening (thyroid, glucose) may be indicated.
7. Treatment
7.1 Conservative Management
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Rest, NSAIDs, and physiotherapy (eccentric strengthening, stretching)
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Ultrasound-guided needling and lavage (“barbotage”)
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Extracorporeal shockwave therapy (ESWT) — effective in promoting calcium resorption
7.2 Surgical Treatment
Arthroscopic removal is indicated when:
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Conservative therapy fails after 6 months
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Large deposits cause mechanical impingement
Post-operative rehabilitation focuses on restoring full range of motion within 4–6 weeks.
8. Prognosis
Most patients achieve full recovery within 6–12 months.
Recurrence is rare but may occur in individuals with metabolic abnormalities.
Early diagnosis and appropriate therapy significantly improve outcomes.
9. Key Takeaways
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CT of the supraspinatus is self-limiting but may cause debilitating pain.
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Ultrasound is both diagnostic and therapeutic.
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ESWT and arthroscopic removal are evidence-based modern approaches.
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Screening for systemic disorders enhances long-term prognosis.
Quiz
Q1. Which imaging modality has the highest sensitivity for detecting calcific tendinopathy of the supraspinatus?
A) X-ray
B) Ultrasound
C) CT scan
D) MRI
Answer: B) Ultrasound
Explanation: Ultrasound offers near 90% sensitivity and provides dynamic evaluation.
Q2. Which phase of calcific tendinopathy corresponds with maximum pain?
A) Formative
B) Resting
C) Resorptive
D) Chronic
Answer: C) Resorptive
Explanation: Pain peaks during resorption due to inflammatory vascular infiltration.
Q3. Which treatment has proven to accelerate calcium deposit resolution?
A) Oral corticosteroids
B) Barbotage
C) Physiotherapy alone
D) Surgical decompression
Answer: B) Barbotage
Explanation: Ultrasound-guided barbotage aspirates deposits and reduces inflammation.
Q4. Gartner type III calcification on X-ray indicates:
A) Formative phase
B) Resorptive phase
C) Chronic fibrosis
D) Tear formation
Answer: B) Resorptive phase
Explanation: Poorly defined, cloudy deposits are typical of resorption.
Q5. The most commonly involved tendon in calcific tendinopathy is:
A) Infraspinatus
B) Subscapularis
C) Supraspinatus
D) Teres minor
Answer: C) Supraspinatus
Explanation: Approximately 65–70% of all cases involve the supraspinatus tendon.
References
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[4] P. Louwerens et al., “The prevalence and clinical consequences of rotator cuff calcific tendinitis,” Arthroscopy, vol. 32, no. 8, pp. 1651–1657, 2016.
[5] R. Kim et al., “Ultrasound-guided barbotage versus ESWT in shoulder calcific tendinitis,” Clin Orthop Relat Res., vol. 475, no. 8, pp. 2040–2051, 2017.
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