bb44,I am so sorry for just getting here now but have been away for a bit.
I agree with Judy. In osteoarthritis, sometimes muscle spasms can be the most troublesome and painful part of the condition. Certainly, physical therapy maneuvers such as ultrasound massage and those modalities can be helpful. I would ask her physician about physical therapy as a possibility for your Mom.
My husband just had a bad flare of his arthritis and warm heat to the affected areas helped him, however, he ended up on a 16 day run of Prednisone. He does use Aleve sparingly for pain when he is not in a bad flare.
I hope your Mother finds something to help here. Again I am sorry you did not get a prompt response.
Kindly,
Kitt