A tearful Hsu, the Taiwanese world record holder and double Olympic champion at 53kg, injured her right elbow on her third snatch attempt and left for treatment at the Anaheim Convention Center before Sopita emerged for her first clean and jerk.
There was better news for Taiwan in the women's 58kg class, however, when Kuo Hsing-chun made six good lifts to defeat another Olympic champion from Thailand, Sukanya Srisurat, with Latvian teenager Rebeka Koha claiming third.
Kuo had finished third to Sukanya at last year's Games in Rio but won easily with a combined total of 240kg.
Sopita, who was fourth at this weight class behind Hsu in the last world championships in Houston two years ago, won in Rio when she dropped down to 48kg.
Back up again in weight, she made a total of 210kg to finish well clear of Kristina Shermetova of Turkmenistan and Hidilyn Diaz of the Philippines.
Hsu, competing for the first time since Rio, was one of only two world champions defending the titles they won in Houston. Thirteen holders are absent because nine nations are banned for multiple doping offences, and North Korea did not enter.
Georgia's Lasha Talakhadze, world record holder in the men's super-heavyweight class, is the other champion lifting at the event.
(Reporting by Brian Oliver; Editing by John O'Brien)
