How is foreign body synovitis diagnosed
clinical, laboratory, and radiographic features of foreign body synovitis
The joints of the hands and knees are most commonly affected. There is sudden onset of pain at the site of injury, which may be forgotten by the patient or overlooked by the physician. The patient may be seen with acute synovitis several days after the injury, ranging from months to years later, with chronic synovitis (particularly of the knee). The inflammatory synovitis may be episodic. The ESR is usually normal, and synovial fluid is inflammatory with a predominance of neutrophils. Radiographs may show soft tissue swelling only and can be useful to detect radiodense particles (metal, fish bones, and sea urchin spines) but not wood, plastic, or plant thorns. Chronic changes of periarticular osteoporosis, osteolysis, osteosclerosis, and periosteal new bone formation can mimic osteomyelitis or bone tumors. Synovial biopsies show a nonspecific granulomatous synovitis that may be confused with sarcoidosis.