Q. I took my lab out to play in 2 ft of snow and she was running around all of a sudden stopped and whined and held her back paw up. What's the problem
DAVID ELBEZE, DVM, MRCVS
A. holding the rear leg up because of pain in labradors is usually a crutiate ligament injury (ligament in the knee joint), it's very painful and requires surgery in order to repair it. Hopefully for you it's not that, it might be something stuck under the paw (try to have a look yourself) or could be soft tissue trauma - in this case a few days of complete rest could resolve the problem.