Working as it does with the support of warm water, hydrotherapy can be really helpful for people with arthritis or joint pain. It's a great way to regain mobility and strength.
Drink some water, have a little something to eat, and rest up. Your therapist may recommend stretches and exercises for you to do at home.
Once to three times a week is great at first. Although, of course, your therapist will come up with a plan that suits you.