The cast and crew of the musical comedy were wrapping up the project in late November, 1979, when Belushi, high on cocaine, borrowed a passerby's skateboard.
The tragic star crashed, severely injuring his knee, prompting studio executive Lew Wasserman to call in California's best orthopaedic doctor after-hours to treat his leading man.
In a new Vanity Fair expose about the making of the movie, editor Ned Zeman writes, ""(Co-star) Daniel (Aykroyd) gets a call from (producer Bob) Weiss. 'You better get down here,' Weiss says. When Daniel arrives, Weiss explains. A kid had ridden past Belushi on a skateboard. Belushi asked to ride the board. Belushi fell off the board.
""Daniel finds the star clutching his knee and in serious pain. 'This was bad,' Daniel recalls. 'We had to deal with it in the most effective and emergency-like way.'
""Wasserman calls the top orthopaedist in town. 'It's Thanksgiving weekend,' the doctor points out. 'I'm on my way to Palm Springs.' 'Not yet,' Wasserman replies.
""Thirty minutes later, the orthopaedist wraps and injects Belushi, who then grits his way through the finale.""