An Elderly Man with a Swollen Knee,Significant Ecchymosis, and Minimal Knee Pain.

A 72-year-old man presents with left knee pain and swelling over several days. The pain and swelling started after he felt a "pop" when bending to pick up an object off the floor. His past medical history is significant for type 2 diabetes mellitus. Physical exam revealed significant ecchymosis on the anterolateral aspect of the thigh. There was a minimal amount pain upon knee flexion.