When I make a fist, I have trouble straightening out my ring finger.  Sometimes, I have to use my other hand to force the ring finger to straighten. 
Is this arthritis?

common orthopedic conditions explained

No, the problem is unlikely to be arthritis.  The most likely issue is something called a trigger finger.  The tendons that flex the fingers catch and this causes the pain and locking.

What can be done for trigger fingers?

common orthopedic conditions explained

There are many effective treatments for trigger fingers.  Avoiding repetitive squeezing and gripping activities will help.  Wear a brace or a cortisone injection can also alleviate the problem.  The last resort is a minimally invasive surgery.

Hands