A pending dispute over an employee’s workers compensation claim could prevent Chrysler Group L.L.C. from using an exclusive remedy defense in a related civil lawsuit, a Missouri appellate court ruled Tuesday. Kevin Cooper slipped and fell while working for Chrysler in March 2007, and filed for workers comp a week later, court records show. Mr. Cooper underwent surgery for his injuries in 2008, but Chrysler argues that the procedure was unrelated to Mr. Cooper’s workplace accident.