My horse is like this too, mainly in his back legs. His problem is left with a GIANT turn-out he will stand in one spot for the majority of the time. It doesn't cause my horse to be lame at all, just makes warm-ups a little longer to get the swelling down. Usually after a good ride, with a lengthy warm up and cool down, the swelling goes back down, but was usually back by the next day.
I started putting him on a joint supplement a year ago and that has helped tremendously! After a couple months on an expensive joint supplement I even switched him to just MSM (cheaper, $20 for 3 month supply) and that worked just as well. He hasn't been stocked up for months, but this last couple weeks I ran out of joint supplement and BOTH tack stores were out of supply so his back legs got stocked up again.
Take a ride across the badlands
Feel that freedom on your face - Breathe in all that open space
You'll understand why God made -Those fly over states