I Am 67 Years Old 5'11" Tall And 185 Lbs.

I am 67 years old 5'11" tall and 185 lbs. Retired recently, exercise 4 -5 time per week, play golf, softball and had knee replacement 2 1/2 years ago. Left hand is getting worse quickly with stiffness and pain. Hurts to know swing golf club. What exercises can I do to help from getting worse. My mother's hands where terribly stiff and crooked when she died at 86 years of age.
Kevin Kyle