Acute calcific periarthritis of the thumb: Correlated sonographic and radiographic findings

The diagnosis of acute calcific periarthritis is traditionally confirmed from a radiograph demonstrating periarticular calcifications in the affected area. Care must be taken when using ultrasound as the presentation of periarticular calcification is easily mistaken for a cortical avulsion fracture, requiring a radiograph to distinguish between the 2 differential diagnoses. We present the correlated ultrasound and radiographic findings of the hand of a 37-year-old man who was suffering from a dull ache in his thumb followed by acute severe pain 1 week later, and make the diagnosis of acute calcific periarthritis of the first metacarpophalangeal joint.