But the 30-year-old said he hoped to regain fitness in time for Pakistan's summer tour of England, despite also suffering problems with the other knee and his left ankle.
"I am going to Australia next week to have a specialist's opinion on the two injured knees and if they advise an operation then I will go through it and hopefully get fit for the England tour," Akhtar told AFP on Thursday.
"I don't want to miss the England tour, and hope that I make it after healing the injuries," said Akhtar.
Akhtar, who has taken 165 wickets in 42 Tests and 199 wickets in 129 One-day internationals, said he would consult Australian surgeon David Young next week.
A Pakistan Cricket Board medical panel diagnosed the degenerative disease in his left knee but Akhtar said his right knee has also caused him trouble for a long time.
"Both my knees were causing problems but I played on despite these injuries, just for the sake of my team," said Akhtar, who took just four wickets in Pakistan's 2-0 home Test series win against India early this month.
Pakistan will tour England from mid-June to play four Tests and five One-day internationals, and Akhtar said he desperately wants to play.
Captain Inzamam-ul Haq and coach Bob Woolmer -- who have both criticised Akhtar's commitment in the past -- hailed his change in attitude in last year's victorious home series against England, when he took 14 wickets.
The injuries are a fresh blow for Akhtar, who is already ruled out of next month's tour of Sri Lanka and who missed the home One-day series against India due to a stress fracture of his left ankle.
Pakistan Cricket Board director operations Salim Altaf said Akhtar was an "asset" and everything possible would be done to get him fit.
"Shoaib bowled in pain in the Test matches on generally flat pitches, which aggravated his ankle and knee injuries," Altaf said.
"Initially we thought it was a cartilage problem but the MRI scans revealed it's a bit more serious."
Altaf said it was too early to say whether the injury was career threatening.
"We'll only find out once he sees the surgeon," he added.
Pakistan suffered badly through injuries to Akhtar, allrounder Shahid Afridi (rib) and Umar Gul (back) during their 4-1 loss to arch-rivals India in the One-day series which finished early this week.