(Adds details on outlook)

Jan 13 (Reuters) - Orthopedic device maker Stryker Corp said on Tuesday it expects the strong U.S. dollar to have a bigger negative impact on its 2015 earnings than it previously forecast, shaving about 20 cents from its per-share profit.

The maker of artificial hip and knee joints previously forecast a currency impact of 10 cents to 12 cents on its 2015 earnings.

U.S. manufacturers such as Stryker that sell products overseas are hurt by a rising dollar when they exchange revenue earned abroad back into dollars.

The dollar has benefited from more upbeat U.S. economic prospects compared with the rest of the world and is trading near a nine-year high against the euro.

Kalamazoo, Michigan-based Stryker also forecast adjusted fourth-quarter earnings of $1.43 to $1.45 per share, with net sales growing 6.1 percent to $2.6 billion.

Fourth-quarter sales rose 12.1 percent in the company's medical and surgical products business and 1.7 percent in orthopedics.

Analysts on average were expecting fourth-quarter earnings of $1.46 per share on revenue of $2.63 billion, according to Thomson Reuters I/B/E/S.

Stryker shares were down 1.3 percent in after hours trading.

(Reporting by Susan Kelly in Chicago; Editing by Bernard Orr and Andre Grenon)