Medtech firm Zimmer Biomet Holdings beat Wall Street estimates for first-quarter profit on Thursday, on the back of robust demand for its devices that are used in knee and hip reconstruction procedures. Zimmer's results extend a strong quarter for medical device makers, including peer Stryker Corp which raised its annual profit outlook betting on steady demand for its hip and knee implants. Investors have increased expectations for medical device makers following a post-pandemic surge in demand for medical procedures, especially among older Americans.