Sternoclavicular Joint Inflammation is NOT Costochondritis
No, inflammation, swelling, and tenderness of the sternoclavicular joint is a distinct entity from costochondritis and should not be labeled as such. 1, 2
Key Anatomical and Clinical Distinctions
Costochondritis specifically refers to inflammation of the costochondral junctions (where ribs meet costal cartilage) or chondrosternal joints (where costal cartilage meets the sternum), typically affecting ribs 3-7. 2, 3, 4 The sternoclavicular joint is anatomically separate—it is the articulation between the clavicle and the sternum, representing the only diarthrodial connection between the axial and appendicular skeletons. 5
Why This Distinction Matters Clinically
The differential diagnosis and workup for sternoclavicular joint pathology differs substantially from costochondritis:
Sternoclavicular joint involvement suggests different disease processes, including spondyloarthritis (where bone scans show 100% sensitivity for detecting sternoclavicular joint inflammation), SAPHO syndrome (which frequently involves sternoclavicular joints with characteristic osseous sclerosis and erosions on CT), septic arthritis, osteoarthritis, rheumatoid arthritis, and even neoplasia. 1, 5, 6
The American Heart Association explicitly distinguishes "musculoskeletal chest pain due to costochondral junction syndrome (Tietze)" from other entities, defining Tietze syndrome as localized inflammation of joints between ribs and costal cartilage—not the sternoclavicular joint. 1
Sternoclavicular joint swelling requires more aggressive investigation than typical costochondritis, as serious conditions like septic arthritis, metastasis, or primary bone tumors may present similarly to benign osteoarthritis. 6
Diagnostic Approach for Sternoclavicular Joint Pathology
When encountering sternoclavicular joint inflammation, swelling, and tenderness:
Obtain baseline investigations including complete blood count with differential, ESR, CRP, and plain radiographs, though radiographs may show variations in anatomy requiring further imaging. 5, 6
Consider bone scintigraphy as it demonstrates 100% sensitivity for detecting sternoclavicular joint inflammation in patients with anterior chest wall pain, particularly valuable for early identification of spondyloarthritis. 1, 2
CT imaging is superior for characterizing osseous involvement, showing sclerosis (77.3%), erosions (44%), and hyperostosis (41%) in conditions like SAPHO syndrome that frequently involve the sternocostoclavicular region. 1
MRI or joint aspiration/FNAC should be performed when clinically or radiologically indicated to rule out infection or neoplasia. 6
Critical Clinical Pitfall
Do not dismiss sternoclavicular joint swelling as simple degenerative changes or mislabel it as costochondritis. 6 While osteoarthritis is the most common diagnosis in sternoclavicular joint swelling, infections, primary bone/cartilage tumors, and metastases can masquerade with similar presentations. 6 The European consensus on chronic non-bacterial osteitis specifically lists Tietze syndrome (costochondral inflammation) as a differential diagnosis distinct from sternoclavicular pathology. 1
Treatment Implications
Unlike costochondritis (which typically responds to NSAIDs for 1-2 weeks with reassurance), sternoclavicular joint pathology often requires joint resection for persistent symptoms when conservative management fails, and acute infections demand urgent intervention. 2, 3, 5