My dad knows someone that tried to kill a deer by jumping off a tree stand onto one with a knife in his hand. I guess his plan was to cut its throat but somewhere between jumping on the deer and the deer getting away he nearly cut one of his fingers off.
With enough practice, I would rather chuck a spear at one from a tree than try to tackle one with a knife. I killed a deer from a tree with a rifle last season at less than 3 yards, close enough that I could have jumped and landed on it. The whole thing was part of why I am getting into traditional archery. One thing for sure is that a .30-30 at point blank range, quartering away and shot in such a way that the bullet went in behind the shoulder and exited at the lower jaw is a shot that didn't require any tracking. It's a little too easy to gun a deer down at such a close range, not even an uncommon occurrence for them to get that close. About half the deer i've taken have been within 20 yards.
I've also heard that you can find a well worn deer trail. Cover your scent as well as you can and dig a hole for yourself across the track. Lay down in the hole, cover yourself with brush, and wait with a large knife. When the deer steps over you, plunge the knife into it with the same orientation as the ribs, hopefully into enough vital organs that the deer goes down quickly.