Juan Martin del Potro undergoes new surgery on troublesome knee

Former world No. 3 Juan Martin del Potro has undergone surgery on his troublesome right knee for the third time in less than two years as he attempts to jumpstart his stalled career.

Doctor Roland Biedert, the favoured orthopaedic surgeon of Roger Federer, carried out the procedure at a clinic in Bern, Switzerland, his management team said on Wednesday, reports Xinhua news agency.

"del Potro and Biedert had been in contact since January," read the statement on Twitter. "In recent months, Delpo followed his doctors' advice and even tested the knee on a tennis court in Buenos Aires, but the pain persisted. After their first meeting in Bern, Biedert recommended new surgery."

The statement did not provide details of the operation but said the 31-year-old Argentine would be discharged "in the next few days".

del Potro has not played since June 2019, when he suffered a fractured patella for the second time in nine months during the Queen's ATP 500 tournament in London.

He underwent surgery in Barcelona just days later but remained beset by pain and was forced to twice postpone his return to the ATP tour last year.

The 2009 US Open champion has grappled with a long list of injuries in recent years and extended periods on the sidelines saw his career ranking drop to 1,045th place in 2016.

In 2018, he won two ATP titles and reached the final of the US Open, where he was beaten by Novak Djokovic.

del Potro is currently 128th in the ATP men's singles rankings, despite more than 14 months on the sidelines.