After listening to his story, I pointed out the problem was his missing left index finger which he lost at age of six after a heavy brick fell on it. Extra stress caused microtears and inflammation in his flexors origins on medial epicondyle. Four sessions of acupuncture and stretching exercise in our office has resolved his issue. In order to keep up with his exercises, he'd need to use hand/wrist support to compensate his weakened grip due to missing index finger in left hand.
Now it looks pretty simple to fix something appearing difficult to treat, doesn't it? It takes a clinician who is always keen on the "small" details, no matter which form of medicine one practices, acupuncture or conventional.
Frank He, L. AC., QME, DAOM