How is foreign body synovitis diagnosed and treated?
In the approximately two-thirds of patients with foreign body synovitis attributable to exogenous particles who develop a chronic or relapsing course, diagnosis and treatment usually necessitates excisional biopsy with synovectomy. Because of its resolution, ultrasound is better than computed tomography (CT) scanning and magnetic resonance imaging (MRI) in detecting particles that are too small or radiolucent to be seen with conventional radiography. Bacteriologic studies (including mycobacterial studies) and histopathologic examination of tissue are essential. Polarized microscopy is useful in detecting birefringent fragments of plant origin, sea urchin spines, and polymethylmethacrylate.