An elderly man was injured in an elevator mishap at a rehabilitation center in Saddle Brook on Thursday night, police said. The 68-year-old man from Cedar Grove was visiting a relative at the Kessler Institute for Rehabilitation on Market Street with his son, when the elevator door opened and his arm and leg got trapped between floors, according to Police Capt. John Zotollo. The man was taken to Hackensack University Medical Center by the Saddle Brook Volunteer Ambulance Corps. Police are investigating the cause of the accident.