Calcium on the knee.?

I picked up a rescue horse late in the fall.. 20 year old reg. Q/H gelding, with a very pleasant personality. This was a high performance horse in his younger years. From his behavior and training, I am guessing he was a barrel racer. I am also guessing that he was used a lot, ridden hard, and the signs are that he was stressed in is early years. The fellow that gave him to me was using him for trail riding on maintained municipal trails. He had him for about ten years, and in that time the horse was ridden light, and more recently, he wasn't using him anymore, just keeping him as a pet. . However, the papers did not come with the horse. At some point in the past the horse was sold, and there was some kind of disagreement, and the papers disappeared. I am pretty sure this horse has really good blood lines, but I, and the previous owner, do not even know the horse's registered name.

The horse must have sustained a knee injury at some point. He has two good sized lumps of calcium deposit on the nearside fore knee, one inside and one outside of the front of the joint.. It does not seem to be painful, and I don't feel a lameness when I ride. I would describe it more as a bit of stiffness, depending on which lead he is on. The horse is in good shape otherwise. However, the knee is qiute stiff when lifted high, and the farrier will trim, but won't shoe him, because it will hurt to keep the foot up that high, and for any length of time. He trims with the foot out straight on his farrier's rest, rather than lifting it like he does with the other hooves. I am using him accasionally for short easy walking rides, 30 minutes or less, on groomed trails, If I think there is any pain, I won't take him out.

I am using linament like Tuttle's and Bigeloil. I have done a bit of research. My experience says I don't think I can do much with this problem. I have not consulted with a vet yet, but I will. The spring visit to the stable for anual shots (even for the barn cat) is not far away.

Sorry for the long story. I am wondering if anyone has any suggestions that might help a horse with a calcium deposit on the knee. I have seen some good suggestions for other problems in this forum. It doesn't hurt to ask for suggestions. Thank you for any response..