Atlantic Southeast Airlines had a CRJ200 main gear shear off on landing a few years ago. No significant injuries and not all that much damage to aircraft either. Bombardier said it was a manufacturing defect.
There is also a significant problem with CRJ700 gear doors cracking or falling off planes. So far the solution has been to take the gear doors off that are cracked, send them away for a few months to be repaired, and then wait until they crack again. Aircraft is limited to .78M cruise with the gear door(s) removed.