Oh my gosh, what has happened to Richard Dragon's leg? It looks like it has no bones at all on the cover of Richard Dragon, Kung-Fu Fighter 13 (Jan/Feb 77).
Richard's leg is in fine condition in the story inside, by O'Neil and Estrada. The tale begins as Ben Turner gets shot with a poisoned dart. He collapses, and Richard and Lady Shiva deal with the attackers.
Once they have disposed of them, they bring Ben to the hospital. Young Ben is back, so I guess Barney Ling took good care of the boy while the others were in Asia. Bad news for big Ben, though, the poison he received is not one the doctors can do anything about. Shiva informs Richard that she recognized the fighting style of the attackers, that they are part of the League of Assassins, frequen foes of Batman. The poison, she deduces, was likely made by the Viper, who works for the League.
So Lady Shiva and Richard Dragon head to Mongolia, and the Viper's lair, to try to force him to give them the antidote. They fight off quite a few members of the League of Assassins along the way.
But when they reach the Viper he tries to flee by helicopter. He flies towards the Russian border, and winds up getting shot down and killed. Now there is no cure for Ben.