When I went for my blood tests, I used to tell the doctors that my hands were very painful and I could not make them straight. One of them had been very kind and let me put my hand on his lap.
I was working hard to find way to make my hands straight again. I followed the instruction of the physiotherapist closely to use the pulley consistently. I could feel my hands were able to go higher and I could make them quite straight slowly. I continue the exercise with hope.
I moved on with monkey bar to make use of my body weight to pull my hands up and straighten them. I adjusted the monkey bar height to the level I could reach with my foot on the floor. I slowly squat down to the level I could tolerate the pain. Many months of painful exercise, I did it and my hands could/can go straight up without any problem anymore.