The movie, set during World War I, took in $3.2 million (£2 million) in its third week of release, seeing off competition from George Clooney's new film The Descendants.
The drama debuted in second place with $2.9 million (£1.8 million), while Liam Neeson's survival blockbuster The Grey was third with $1.8 million (£1.1 million).
Animated family film A Monster In Paris landed fourth with $1.6 million (£1 million) while Oscar favourite The Artist rounded out the top five with $1.1 million (£704,000).
