EE stepped off of a raise platform(8"" high)to the floor of the 1570's house. When EE stepped off the raised area EE heard a pop in the L knee. Knee x-rayed, inconclusive. EE returned to work on restricted duty awaiting a MRI. EE due to swelling was unable to work on 03/20/2015 & will return after the MRI pending the results. To date no medical treatment has been performed.