Which signs of inflammation are suggestive of acute synovitis in a joint?
Joints affected by an inflammatory arthritis commonly exhibit synovial distention, warmth, and limitation of range. The best indicator of synovitis is a distended joint capsule, especially if accompanied by warmth. Swelling due to joint effusions may also occur in the noninflammatory arthritides (e.g., osteoarthritis of knee). Inflamed joints are not typically erythematous, with exception of acute septic and crystalline arthritis. If you encounter red, hot joints, particularly in a monoarticular distribution, your first thought should be “where is the needle?” (joint aspiration).