How To Treat Pain In Finger And Knuckle Despite Being Diagnosed With Osteoarthritis?

Hi I have Ostio arthritis in my right ankle knee and hip more recently i have had lots of pain in my index finger i cannot open my hand out flat and have lots of pain in my knuckle, my finger is curled like a claw and when i do try to open it up i get pain right up to my wrist could this be the start of arthritis in my fingers its sp painful