If the knob itself came off in your hand it s probably the kind that slips over a cylindrical spindle which is mounted to the door as part of the latch assembly.
Door handle came off front door.
The front door handle is the first picture and if you compare it to the second one you can see that the part that connects to the opening rod the yellow piece is broken off on the front handle and not on the rear.
My front exterior door has a lever handle that started to pop out a few months ago.
Look for a little slot on the door end of the knob then find a small matching button on the side or underside of the spindle.
The house door handle will continue to come off even after putting the handle back on.
This would be confirmed by looking at the interior lever where there is a set screw that is screwed out from the shaft to hold the lever using the hole in the lever.
I ve been slowly poking around trying to figure out how to fix it and i now suspect there was a set screw on the shaft of the handle that fell off and is probably now sitting somewhere inside my door.
Typically the problem is the result of a missing or loose screw in the house door plate.
It has a loose or missing screw in the door plate.
These problems could stem from a broken spindle or a door knob trim that is rusted or held up by debris and dirt.
The locking mechanism on the house door handle might fail to properly open and latch the door.
It is aged and subjected to buildup of dirt dust and other pollutants that hinders the operation of the handle or lock.
The door handle s locking mechanism might be malfunctioning.
15 to 30 minutes this video will guide you through the process of repairing replacing or tightening your door handles at your home.
It becomes wobbly or loose over time and needs to be adjusted and made tight again.
The exterior handle came off.
Looking at it there s a small hole in the lever and your first thought is that the set screw used to hold the lever in place came loose and fell off.