PT STEPPED DOWN FROM A METAL GRATE ONTO A PAINTED METAL SURFACE & SLIPPED & FELL ONTO THE SIDE OF HIS LEFT KNEE ABOUT 10 PM LAST NIGHT'S SHIFT. HE C/O LEFT KNEE PAIN, SWELLING, CATCHING. HE WO RKED THE REMAINDER OF THE SHIFT BUT DID NOT DO MUCH WALKING BECAUSE OF PAIN.