Interesting, informative read -- thanks for posting.
I had read somewhere about how bone formation compensates for the stress that's put on key areas -- hence the terms "pianist knuckle" and "tennis elbow".
Densmore himself was unable to make the Doors of the 21st Century/Tiders on the Storm tours. Initially he was on board, but then later made a show of suing the others for using the sacred name of "Doors" for these outings.
In fact, Densmore was no longer able to handle the demanding workload these songs required, because he had developed tendonitis in one or both shoulders.