Landa crashed and sustained the injury at the Clásica San Sebastián in August and was unable to return in time to race the Vuelta a España alongside his Movistar team-mates Alejandro Valverde and Nairo Quintana.
The Basque rider returned to racing for the first time on Wednesday at the one-day Giro della Toscana in Italy, but failed to finish.
In a statement, the Spanish Cycling Federation said Landa then contacted national coach Javier Mínguez following the race to tell him that "he still didn't have good sensations on the bike" and that he couldn't compete in Innsbruck on September 30.
Landa will be replaced by Astana's Omar Fraile, who was unlucky to miss out on initial selection after a stellar season which saw him win a stage of the Tour de France as well as stages at the Tour of the Basque Country and the Tour de Romandie.
Omar Fraile wins stage five of the 2018 Tour of the Basque Country (Sunada)
(Image credit: Yuzuru Sunada)
Fraile will form part of the eight-man road race squad along with a strong line-up including Alejandro Valverde (Movistar), Enric Mas (Quick-Step), Ion Izagirre (Bahrain-Merida), Jesús Herrada (Cofidis), Mikel Nieve (Mitchelton-Scott), David de la Cruz and Jonathan Castroviejo (both Team Sky).
Get The Leadout Newsletter
The latest race content, interviews, features, reviews and expert buying guides, direct to your inbox!
The Innbruck course for this year's Worlds will be a brutal affair, but present a rare opportunity for the pure climbers with over 5,000m of climbing in the 265km course.
For the time trial, which takes place a few days before the road race, Spain will send national champion Castroviejo along with one of Marc Soler and of Imanol Erviti filling the other spots. Selection will be decided based on how either rider performs in the team time trial for Movistar, which takes place this Sunday on September 23.
Thank you for reading 20 articles this month* Join now for unlimited access
Richard is digital editor of Cycling Weekly. Joining the team in 2013, Richard became editor of the website in 2014 and coordinates site content and strategy, leading the news team in coverage of the world's biggest races and working with the tech editor to deliver comprehensive buying guides, reviews, and the latest product news.
An occasional racer, Richard spends most of his time preparing for long-distance touring rides these days, or getting out to the Surrey Hills on the weekend on his Specialized Tarmac SL6 (with an obligatory pub stop of course).
