A palm thorn penetrated my knee about a month ago. Though I never had arthritis before, I now have a mild case in my right knee, puncture healed, tetanus shot next day, no warmth or swelling--just light arthritis. Ultrasound showed nothing. My GP does not know what to do. I live in Maui, HI, and no doctor here for it. I can fly anywhere to get this taken care of. Who would be the best doctor to see?