Yikes!! How'd that happen?
Those in the know recommend the labonville chaps. Especially the ones that wrap around the calf.
These are what I use. The competition model. Example: Amazon.com : Labonville X-Treme Competition Chainsaw Safety Chaps - X-Large : Chain Saw Accessories : Patio, Lawn & Garden
They have saved a thigh twice- both times at the end of a long, hot day when I was tired and not paying enough attention. I will not use a chain saw for any reason without having chaps on.