This works if you are fitting a genuine replacement knob.
Hacksaw the old one off, top to bottom!, mind the reverse gear pawl, cut down to the metal part, remove all the plastic remaining, does the job nicely - but be careful!
DONT HAMMER the new knob in place otherwise you will destroy the lower plastic ball joint. To fit the new knob, push down with all your weight and twist as it goes on, bugger to do but better than wrecking your stick with a hammer!
Bob RTE