Stoke City came close to signing Ba in January 2011 but a deal was not finalised after he failed a medical, with Tony Pulis saying at the time that the medics 'obviously found something which could cause problems later'.
Ba went to West Ham United instead and, after a successful spell with Newcastle United, says Chelsea had no concerns about his long-term fitness when they brought him in last week.
"My left knee? There was absolutely no problem on that level with Chelsea," the striker said in L'Equipe.
"I don't like to talk about that, but just have a look at the number of matches I have played since I have been in England (65 in the Premier League). The answer should be enough to satisfy everyone."
Ba made a stunning start to his Chelsea career as he scored two goals in a 5-1 FA Cup demolition of Southampton, and is available to face Swansea City in their Capital One Cup semi-final on Wednesday.
He admits that Chelsea will have to focus on the domestic cup competitions, as well as the Europa League, as they are currently 14 points behind leaders Manchester United in the Premier League.
"In the Premier League it will be difficult to catch Manchester United again to overtake them in the end," he said.
"However, we are still in competition in three cups and we will try to win as many titles as possible."