Sorry to hear you was injured, i had a similar experience. Unfortunately it appears that there's a lot of people experiencing the same problem. The response on here to anyone that has had this problem is the common response of ''Apple Watch cannot detect all falls'' . But hard falls where you fall hard enough as you have to break your tibular or in my case i was unconscious, and the fall detection doesn't register when someone isn't moving. Surely shows that there is a major issue with one of the major advertised features of these watches !! As per usual you will see someone will reply trying to mask the problem, which many like yourself are experiencing.