I dont think WICKED has had any major injuries aside from SJB and Idina but those were freak accidents (Idina's could happen to any actor who makes an exit via a elevator on the floor)
But the dancing they do in Ozdust is pretty extensive in terms of flinging their bodies in awkward positions so who knows how many are injured. It always seems like the swings are on so maybe it is tough
"Life in theater is give and take...but you need to be ready to give more then you take..."