Falafel falling apart is one of the most frequent problems when making falafel. This is very likely to happen when using canned chickpeas, and not dried ones (you'll find more information on dried chickpeas in this recipe). Another reason is that you didn't allow the mixture enough time prior to use. After blending the ingredients, cool the falafel mixture in the fridge for about 1 hour. I've compiled an article with the 7 most common reasons for falafel falling apart and how to fix the mixture.