ST. LOUIS (AP) -- Rehabilitation services company RehabCare Group Inc. said Tuesday it will buy hospital operator Triumph Healthcare for about $570 million, expanding the company's hospital portfolio.

RehabCare runs rehabilitation programs in a range of facilities, including hospitals, nursing facilities, and outpatient centers. Triumph, based in Houston, operates long-term acute care hospitals. It had revenue of $439.7 million for the 12-month period ending Sept. 30.

The buyout is expected to close on or about Dec. 1.

RehabCare said the combined company will represent the fourth largest post-acute hospital operator and the third largest long-term acute care provider in the country. It will have 29 long-term acute care hospitals and six inpatient rehabilitation facilities operating in 13 states.