My 3 yr. Old thoroughbred was found stumbling and losing her balance one day in her stall. The vet dx it as locked stifle. After this she showed no more signs of extending the leg backwards with the toe under. Instead that hind leg would have a spasm in it periodically. (Like a shock wave going down her leg). The gaskin and stifle area were a bit swollen, sometimes painful to touch, no heat to the area ever. Called for a second opinion. This vet thinks it could be a partial tear of the ligament. Rural area so no availability for ultrasound or xray to verify. Very different treatment for both. I've had her for 2 weeks, no known injury, past owner is very surprised about all this (she was last raced last in Nov). Any thoughts on this one???