A man was repairing a fence and injured his right elbow with a wire. Three days later he developed edema, hyperemia, reduced range of movements in the joint, intense pain, and local and general increase of temperature. Objectively, the right elbow is enlarged, the skin over it is edematous and hyperemic, regional lymph nodes are enlarged, thickened, and painful. Palpation. of the right elbow detects sharp pain and fluctuation. Make the provisional diagnosis.