Kevin Pietersen could find himself in a race to be fit for England's Champions Trophy campaign in September, after a London-based orthopaedic surgeon warned that he could need considerably longer than the estimated six weeks to recover from the operation he underwent on his right Achilles tendon on Wednesday.

"Kevin Pietersen has a serious problem with his Achilles tendon known as chronic tendinopathy, which hasn't responded to the usual measures of physiotherapy and injections," Dr Simon Moyes, who works out of the Wellington Hospital in St John's Wood, told the Press Association. "Less than five percent of patients end up needing surgery for this condition and therefore he is most unfortunate."

Pietersen was booked in for an operation on Wednesday morning, after struggling throughout England's historic victory in the second Test, in which they took a 1-0 lead in the Ashes series with their first win over Australia at Lord's since 1934. He was never comfortable at the crease, nor in the field, although his twin scores of 32 and 44 took his career tally against Australia to a formidable 1116 runs in 12 Tests, at an average of 50.72.

In a statement, the ECB's Chief Medical Officer, Nick Peirce, said that Pietersen had been operated on by a leading surgeon who had been specially flown in from Sweden, and that the early signs were that the operation had been routine.

"The operation involved a small incision and trimming of the blood vessels and nerves around the inflamed tendon," said Peirce. "Kevin will look to undertake a comprehensive rehabilitation programme to ensure there is no risk of recurrence. This is expected to be approximately six weeks but will be taken at an appropriate pace following constant review."

Moyes, however, warned that there was no guaranteeing a quick fix to Achilles injuries, and said that Pietersen and England might have to be patient in his recovery period. "The surgery to the tendon is not always predictable and involves cleaning inflammatory tissue, necrotic tissue and neovascular tissue - i.e. new blood vessels," he said. "I believe it will be at minimum of three months before he is fully recovered. Even then there is still a risk that the surgery may not work."

"As an England cricketer the Ashes are the pinnacle of the game so I'm absolutely devastated to be missing the rest of this series," said Pietersen. "I hate missing matches for England and especially during an Ashes summer but now that the decision has been made to undergo surgery I'm confident I can return to the England team injury-free following a course of rehabilitation."