The Quick-Step rider developed knee problems following a spate of falls in Switzerland and California.
Tom Boonen: "Last week I experienced less pain, but on Monday I tried to ride 100 km and the pain was unbearable. In consultation with the medical staff I decided to undergo an operation."
Boonen's woes earlier led him to pull out of the Belgian cycling championships and the Tour de France.
Dr Yvan Van Mol: "We tried to heal Tom's injury in a natural way through rest and therapy, but it failed.
Boonen will be able to resume training after 4 weeks. Dr Van Mol: "Only then will we start to think about a comeback. The Vuelta would be ideal preparation for the World Championships in Australia."