I fixed this last night by taking of the legs.
By unscrewing the only screw in the upper hip and pulling the leg off.
There is a screw that holds the wing on, and it's a little hard to get at. Once you unscrew that, the wing comes off.
Break out some clear nail polish and give the hole and knob a lite coat. After they are dry, reassemble.
While you are at it, you might as well use the same procedure on the hips.