The Swiss great said he has faced no setbacks and is recovering well.
The recurring issue flared up at the French Open, where he fell to eventual champion Novak Djokovic in the semi-finals.
Federer will miss the upcoming US Open because he needs more knee surgery, an operation that the Swiss great said will give him a "glimmer of hope" that he can resume his glittering career.
All the cheers and standing ovations in the world could not save Federer from the Centre Court mauling as it seemed his 39-year-old body finally said enough is enough.
The Pole reached his maiden major quarterfinal where he will meet eight-time Wimbledon winner Roger Federer.
Federer scored a 7-5, 6-4, 6-2 win over 23rd seed Sonego.
It was not quite vintage Federer, but the 7,500 fans packed around his favourite court did not care as the Swiss gave them plenty to ooh and aah about in a 7-6(1) 6-1 6-4 victory.
Federer survived a massive scare against Adrian Mannarino before advancing to the Wimbledon second round when the Frenchman retired with a knee injury after slipping on court.
"After two knee operations and more than a year of rehabilitation, it's important that I listen to my body and not rush back into competition," 20-time Grand Slam champion Federer said in a statement.
Federer was beaten 6-4, 4-6, 6-4 by Spaniard Pablo Andujar at the claycourt Geneva Open.