If it looks like the adjustment button has just slipped out of place. To pop it back into place you will need a flashlight, a Philips head screwdriver, and a paperclip. First, unscrew the black plastic cuff that is at the bottom of the crutch upper leg section. Once that is unscrewed you can remove the lower leg section from the crutch. The top of the lower crutch section should have a black plug with a screw in it (don't worry if the plug is missing, it can get stuck in the top of the upper crutch leg). Use the screwdriver to unscrew the screw that is in the plug, then remove the plug. Next, use your flashlight to visualize the push button inside the crutch leg. Then take your paper clip, straighten it out and bend the end into either a small hook (if the push button needs to be pulled up) or an L shape (if the push button needs to be pushed down). Use the hook to pull the push button into place or use the flat bottom of the L to push the push button into place. Once the push button is in place you can put the black plug back on the top of the lower leg section and tighten it using the screwdriver. If the black plug wasn't in the top of the lower crutch leg when you removed it all you need to do is insert the lower crutch leg into the upper crutch leg, push it all the way up to the very top, stand the crutch up, and push down from the top. Then pull the lower crutch leg all the way back out. The black plug should be in place now, so all you need to do is tighten the screw. Then the lower crutch leg goes back into the upper crutch leg, and the black plastic cuff that was removed in the beginning is screwed back onto the bottom of the upper leg section.