Hello, this is Dr. Linda. I hope I can help with your question today.
I am very sorry your paint is having some problems with his front leg. Even though he has not been out for the past 10 days, it is amazing what a horse can do to himself in a stall. He could have banged the knee on the stall door/wall, or spun around in the stall just out of boredom & wrenched it a bit. Hopefully, it is just a strain or mild sprain.
But any soft tissue injury in the horse needs to be taken seriously because of the consequences. Early treatment of primary problems minimizes the extent of possible secondary joint damage.
Many therapeutic options are designed to treat active soft tissue inflammation & prevent progression of articular cartilage damage. Rest is the simplest, but often the most difficult recommendation to enforce. Physical therapy & controlled exercise by hand walking & supervised turnout is advised. I would also include a nonsteroidal anti-inflammatory agent ( such as phenylbutazone of flunixin/banamine ) daily & even the use of a topical anti-inflammatory product such as Surpass Cream for equines.
Cold hosing is also always a good idea. Just make sure the leg is completely dry afterwards, & you might even massage a linament in well ( but not If you use the Surpass ).
I hope this makes sense & you find the information helpful. Please let me know if you have ay further questions or concerns.