Presentation
Swelling and tenderness over the left sternoclavicular joint
Patient Data
Abnormal distension of the left sternoclavicular joint space up to 12 mm. Cortical erosion and irregularity of the adjoining manubrium and left clavicular head, with corresponding abnormal high STIR signal of the bone marrow. No evidence of osteophytes.
Annotated image shows distended left sternoclavicular joint space.
Case Discussion
There is considerable overlap between sternoclavicular joint septic arthritis and osteoarthritis. The following imaging findings may help in favoring infection (many of them are seen in our study):
- joint space distension 10 mm or more
- joint capsule distended with fluid more than 5 mm over the clavicle and sternum
- bone marrow edema and signal alterations
- presence of fever and elevated ESR
Note that findings of erosion, cortical irregularity, and enhancement may be seen in both septic arthritis and osteoarthritis. A narrow joint space is more compatible with osteoarthritis.