No, he didn't. He landed a Push on Ventress, Ventress landed a kick on him, then he deprived Ventress of one of her blades and then she forced him against the railing. He then threw away her detonator and she chased it. By the end of the fight, Ventress was clearly the one in the advantageous position, and Koon generally fights one-armed anyway. His broken arm wasn't really a hindrance in that fight.