EE SLIPPED AT THE BOTTOM OF SOME STAIRS LEADING TO THE THICKENERS AT THE AUTOCLAVE. THE CONCRETEPAD AT THE BASE OF THE STAIRS WAS DAMP & MUDDY HE FELL TWISTING HIS RIGHT KNEE & STRIKING IT ON THE CONCRETE HE WAS EVALUATED AT THE ER & GIVEN A FULL DUTY RELEASE. HE HAD A PREVIOUS INJURY IN1989 TO RIGHT KNEE. THE KNEE CONT TO BOTHER HIM & ON 9/5/00 SURGERY ON THE KNEE AFTER MRI REVELA