EMPLOYEE (LAB TECH.) STEPPED OUT OF LAB DOOR TO WALKWAY TO WALK TO SCALES, BOOT SLID ON BAR GRATING RAMP & HE STRUCK THE HANDRAIL W/HIS RT. KNEE. EE NEVER LEFT WORK & CONTINUED WORK EVERY DAY. APPT. W/COMPANY DR. 2/2/05 RESULTED IN A MRI 2/3/05, THE RESULTS WERE READ ONLY TODAY. HE HAS A CRACKED PATELLA RT. KNEE & HAS AN APPT. W/AN ORTHOPEDIC DR. IN A FEW DAYS. WILL KEEP WORKING.