foot drop
n.— «I underwent a hip operation in 1997 and was attempting to get back in trim but was concerned about my right leg, I had something called “foot drop.” It didn’t lift up and didn’t quite work.» —“How MS has changed by life” by Alastair Hignell This Is Bristol (United Kingdom) Aug. 27, 2008. (source: Double-Tongued Dictionary)
Foot drop is a pretty standard medical diagnosis.