Does a touchpad button malfunction require top case replacement?

I had a different kind of trackpad button failure (mine was stuck as permanently clicked, which prevented booting), but was able to get around it by snipping the cable to the button only (under the battery). The keyboard and trackpad work as usual, and I turned on trackpad-tap-clicking, which takes some getting used to but works just fine. The one caveat is if you do a reinstall, you'll need to borrow a USB mouse, because the OSX installer doesn't default to tap-clicking.

It's nearly impossible to fix a broken trackpad on a MBP - the mechanism is spot soldered/welded in place and there is no way to remove the button without damaging the unit, let alone the trackpad itself.

You need a new top case. Sorry.

I have the exact same problem. Cleaning around the edges fixed the problem for about a week, then it came back with a vengence and cleaning again didn't help. I didn't even realize that tapping the trackpad could often substitute for clicking the button/bar, and figuring that out of course helped - but there are still times that one has to click.

I also discovered, however, that simply resting my plam or pressing on the topcase anywhere to the right of the trackpad activates the clickbar/trackpad button as if it had been pushed. It doesn't take much pressure either. This seemed to be the cause of some of my worst "stuck clickbar/button" episodes.

It's almost second nature to rest my right palm just to the side of the trackpad while using it - but being sure I'm NOT doing so has really reduced this problem. When it still seems stuck, sometimes just using a fingernail with a little pressure on the edge of the click bar/button closest to you and flicking upwards (like you're trying to move the button upwards) once or even a few times if necessary will unstick it.