Ultrasound measurement of knee synovial fluid during external pneumatic compression.

Synovial fluid based biomarker research has been limited by the small volumes of synovial fluid from the knees of some patients. We used ultrasound (US) to determine if synovial fluid could be displaced into an access port during pneumatic compression to 100 mmHg. Forty knees from 37 consecutive arthritis patients with rheumatoid arthritis -25, osteoarthritis -8, psoriatic arthritis -2, and 1 each with systemic lupus erythematosus and gout were evaluated.