I had the same problem with my elbow, electrotherapy did not help. Turned out it was systemic inflammation in my body that was preventing it from healing. Change of diet fixed it.
Something that has really helped with inflammation and improved my diet is a Spirulina and Chlorella algae supplement. I take it with Metamucil to help with absorption in the intestines as well. If you use the powder version, Metamucil covers up the umami taste, but the tablets are tasteless.
This is from some research that shows spirulina can absorb toxins, and then when I take Metamucil, it helps to slow my body's processing of the supplement.
What I have noticed is that the increase in nutrients will go through me super fast since I have a lower fiber diet, but when I have taken it with Metamucil, the fiber increase really slows down my bodily function. I figured if the algae is moving more slowly, it should also be able to have a higher absorption rate since it stays in my body longer.
Spirulina had a moment, and I took it, in the UK in the 90s. I'm struggling to remember exactly why I took it or stopped taking it, but, as a veggie, it did seem to offer everything else I might be lacking in my diet.
As I've aged my digestion is no longer as robust as it was, so I'm keen to give spirulina another go, plus the husks (metamucil is especially good, you think?) for a few months and see if I feel any different.
The removal of heavy metals is a plus, though I also am a little skeptical of how essential removal is, or of the genuine serious long term damage caused. I need to read up more.
I stopped eating desserts and sweets, stopped overeating, stopped eating after 7pm, switched to eating more veggies and unprocessed foods. I started taking supplements (ag1 powder, fish oil, turmeric). Once inflammation started to reduce I started to exercise more. It wasn’t just pain in my elbow, it was also in my foot and my shoulder, for many years: all better now.