Medical experts' affirmations established prima facie that the treatment provided by defendants to the injured plaintiff following the surgery on her ankle comported with good and accepted practice. In opposition, plaintiff submitted the conclusory affirmation of an expert who did not address the specific assertions of defendants' experts, particularly with respect to the issues of malpractice and causation ( see Alvarez v Prospect Hosp., 68 NY2d 320, 325; Ramirez v Columbia-Presbyterian Med. Ctr., 16 AD3d 238), and whose ultimate assertions were speculative or unsupported by any evidentiary foundation ( see Diaz v New York Downtown Hosp., 99 NY2d 542, 544; Wong v Goldbaum, 23 AD3d 277, 279).