Knock on wood, I have only had one kettlebell related injury and it was caused by not packing the down shoulder in a super heavy Turkish Get-up.  It is very important that both the shoulder on the bell side and the down side be packed throughout the entire exercise.

I’ve found that many people have trouble feeling what “pack the shoulder means.”  This drill, shown to me by Susan Moore, is the most effective way I have seen to force the packing of the down shoulder.

Set a super heavy bell on its side right where the down hand will be planted (about 45 degrees out from the body.)  As you roll to the elbow, pull the handle of that bell and that will force you to pack the shoulder and show you how the down shoulder works as much as the bell side shoulder. Repeat a few times before continuing in the get-up.