Hit right on the kneecap, so likely irritated tissues/ligaments underneath.
Not that it keeps me from orienteering, but I wanted this recorded so I remember when it happened, if it doesn't improve. Still puffy two weeks later but swelling is much reduced.
Still using ice three weeks later. Sore when touched.
Five weeks into this I slipped (tide pooling in Maine) and banged it again! A bit swollen again, but not much of a distraction otherwise.
April 2015--8 months out...still painful to kneel on, so probably another bone bruise (like in 2009 that took 1.5 years befor I could kneel again on it)
Feb 2016--having fallen on it a few more times in the interim, it finally started acting up at the end of December and still doesn't like being bent past 90 deg (as in pigeon pose). X rays a couple weeks ago didn't raise any red flags to an orthopedist.
June 2016--twisted knee in a fall (but didn't land on it specifically) at the team trials middle and am back to Jan/Feb level of pain, with more swelling. Maybe a different doctor.
Sept 2016--June and Jan level pain reduced to mostly better (no pillow between knees needed when sleeping). Did two orienteering courses 2nd weekend of Sept and knee is sore on the Monday after, so it's not resolved completely.