Kaka in 'perfect shape' after surgery
"Kaka needed to have the surgery, he could not play with the pain he was feeling and the treatment he has had since the operation has been perfect," Doctor Marc Martens told sports daily Marca.
"Now he has a new knee, it is like he had never had the operation. He is in perfect shape. After the surgery we really did not know when he would return. There was an estimated timeline but we did not think he would return so early and in such good physical condition."
The 28-year-old underwent surgery on his left knee on 5 August and only returned to training last month. He returned to action for the first time since his operation on Monday, coming on the pitch in the 75th minute of Real's 3-2 Spanish league win at Getafe.
"I am very happy for playing a game again and for stepping onto a pitch. Coming back with a victory is the best thing that could have happened to me," the player said after the match.
"At times, I was afraid when I thought about when I was going to come back, or if I ever would. I must now earn a spot because the team is in great form. Competition is always good for the team."
Kaka's hopes of reclaiming a first-team place have been hit by the arrival of 22-year-old playmaker Mesut Ozil, who joined Real from Werder Bremen last summer after starring for Germany at the 2010 FIFA World Cup South Africa™.
Prior to his injury, Kaka had struggled to shine due to a combination of injuries and poor form. He joined Real from AC Milan for around €65 million in June 2009, shortly before the arrival of Portuguese forward Cristiano Ronaldo.
Kaka won the Ballon d'Or and FIFA World Player of the Year awards in 2007 while he was at AC Milan.