The world number 12 slipped as he slid for a volley in the second set and later withdrew from the tournament.

Del Potro - a quarter-finalist at Wimbledon in 2018 - has only played five events since suffering the initial fracture in Shanghai last October.

The 30-year-old was due to play at Wimbledon, which starts on 1 July.

Del Potro underwent medical exams after withdrawing from Queen's due to pain and swelling in his knee.

"The surgery will take place in the next couple of days with a date and location to be determined," said his team.

Del Potro, who beat world number 25 Shapovalov 7-5 6-4, was seeded third in the singles at the tournament and has also withdrawn from the doubles with partner and compatriot Horacio Zeballos.