What indicates joint effusion in the knee during assessment?

• A. A positive Lachman test
• B. A bulge sign or ballotable patella
• C. Pain during range of motion
• D. Increased warmth around the joint

Answer: (B)

The presence of a bulge sign or ballotable patella is a classic indicator of joint effusion in the knee. This technique assesses for fluid accumulation in the knee joint. The bulge sign is performed by pressing on the suprapatellar pouch to see if fluid moves around the joint and creates a bulge on the medial side of the knee when pressure is released; this indicates the presence of excess fluid. A ballotable patella involves pressing down on the patella; if the patella floats or bounces back, it suggests that fluid is present in the joint space. These signs specifically demonstrate that there is an abnormal amount of fluid, confirming the presence of joint effusion.

Other indicators like a positive Lachman test are used to assess for ligament instability rather than fluid presence. Pain during range of motion can be associated with various knee conditions but is not specific to joint effusion. Increased warmth around the joint may indicate inflammation but does not necessarily confirm the presence of effusion. Thus, the bulge sign or ballotable patella is a direct assessment technique for identifying joint effusion in the knee.