Appeal from an order of the Supreme Court, Erie County (Joseph D. Mintz, J.), entered September 9, 2004. The order, insofar as appealed from, denied defendants’ motion for summary judgment dismissing the complaint in a medical malpractice action.

It is hereby ordered that the order so appealed from be and the same hereby is unanimously affirmed with costs.

Memorandum: Supreme Court properly denied defendants’ motion for summary judgment dismissing the complaint in this *1145medical malpractice action. We agree with defendants that “[a] plaintiff cannot defeat an otherwise proper motion for summary judgment by asserting a new theory of liability for negligence for the first time in opposition to the motion” (Winters v St. Vincent’s Med. Ctr. of Richmond, 273 AD2d 465, 465 [2000]; see Matacale v County of Steuben, 289 AD2d 949, 950 [2001]). Contrary to defendants’ contention, however, the affidavit of plaintiffs expert presents “no new factual allegations, raises no new theories of liability, and has caused no prejudice to defendants]” (Noetzell v Park Ave. Hall Hous. Dev. Fund Corp., 271 AD2d 231, 233 [2000]; see Johnston v City of New York, 17 AD3d 534 [2005]; Warden v Orlandi, 4 AD3d 239, 241 [2004]). The court therefore properly considered that affidavit and concluded that it raised triable issues of fact with respect to defendants’ alleged malpractice. Present—Pigott, Jr., P.J., Green, Gorski, Smith and Hayes, JJ.