An action for damages for injury or death against any physician, health care provider or hospital licensed under the laws of this state, whether based in tort, breach of contract or otherwise, arising out of patient care, shall be brought within two (2) years of the date the plaintiff knew or should have known, through the exercise of reasonable diligence, of the existence of the death, injury or condition complained of; provided, however, the minority or incompetency when the cause of action arises will extend said period of limitation.
Okla. Stat. tit. 76, § 18