SOUTH BEND, Ind. - In response to what an Indiana federal judge called two "head-scratching" motions, a federal judge in Indiana on Feb. 8 denied Zimmer Biomet Holding Inc.'s (Biomet) motions for summary judgment on a state-of-the-art defense regarding its metal-on-metal hips and for lack of causation testimony in four non-metal-on-metal hip cases (In Re: Biomet M2a Magnum Hip Implant Products Liability Litigation, MDL Docket No. 2391, No. 12-md-2391, N.D. Ind., South Bend Div., 2018 U.S. Dist. LEXIS 20758).