Suspension let me down

[forestcrab]

Hi all, 

I have had a major failure of my front drivers side suspension, it had been making noises for a while and today I found out why. The bag has now burst (I do have a spare) but the the suspension knuckle joint assembly is broken and this has taken a piece of the housing out around the size of a 5 cent piece. It has also damaged the top bump stop. Does anyone know why the knuckle joint would have broken?