The federal government has received a surge in complaints in recent months about failed hip replacements, suggesting that serious problems persist with some types of artificial hips even as researchers scramble to evaluate the health dangers. An analysis of federal data by The New York Times indicates that the Food and Drug Administration has received more than 5,000 reports since January about several widely used devices known as metal-on-metal hips, more than the agency had received about those devices in the previous four years combined. The vast majority of filings appear to reflect patients who have had an all-metal hip removed, or will soon undergo such a procedure because a device failed after only a few years; typically, replacement hips last 15 years or more. The mounting complaints confirm what many experts have feared -- that all-metal replacement hips are on a trajectory to become the biggest and most costly medical implant problem since Medtronic recalled a widely used heart device component in 2007. About 7,700 complaints have been filed in connection with that recall.