Our joints, primarily ball-and-socket and hinge, are there to facilitate our movements. As such the articular cartilages need to be separated by the synovial fluid inside the joint, the cartilages being held in position by the ligament and supported by our tendons. Joint pain arises because some parts of the articular cartilages of the adjoining bones touch and scratch upon each other. It is ultimately caused by an overuse (at certain angle or orientation), and it is immediately caused by the collapse of a certain point(s) separating the cartilages and weakening and shortening of the affected tendons. What makes a cure by chi kung possible is that the collapse is only one pointed or single sided. If we can lift up (or slightly separate) our joints, train our tendons, re-position our bones, so that our bones will be jointed together at a slight different place (with strengthened tendons), then the articular cartilage will not touch upon each other while the joint is in action (i.e. the person in movement in respect of the joint concerned). And we are cured!
It can be done by finely-conditioning of our tendons around our joints. And it can be achieved with a good practice of chi kung, starting with zhan zhuang. The Japanese master said she had many examples of successful cases of healing, and so have I. One caveat, a continual practice is needed to stabilize and/or further improve the situation. Lack of continual practice can easily make the joint fall back into its original (wrong) place!
Note: A number of anatomical terms were mentioned above. Readers have to check their meaning for a good understanding. In future, I will do some explanatory drawings for a better explanation. Until then, do some research for a better understanding.