Diego Maradona is unquestionably one of the greatest footballers of all time.The Argentine icon, who inspired his country to World Cup glory in 1986, was born with a once-in-a-lifetime talent and an insatiable desire to succeed and prove people wrong in the process.That Maradona is something of a flawed genius is another reason why he’s idolised by football fans around the world. He’s not perfect and has never pretended to be. What you see is what you get.Maradona has struggled with various personal problems over the years, including drug addiction, and has even come close to death on a couple of occasions.Back in 2004, for example, the retired forward was left in intensive care after suffering a heart attack - his second heart attack within the space of four years.But Maradona appears to have cleaned up his act somewhat in recent years - he even managed the Argentina national team between 2008-2010 - and is thankfully still with us at the age of 57.Despite that, some worrying new footage has emerged of Maradona struggling to walk in a recent training session.The World Cup winner, who is currently in charge of Mexican side Dorados, can be seen hobbling gingerly onto the pitch alongside another coach.Watch the concerning footage here…

To see a football legend suffering like Maradona clearly is there is extremely sad to see.

Spanish football writer Sid Lowe pointed out on Twitter that some football fans think the footage is amusing, which is disgraceful, quite frankly.

Meanwhile, Maradona’s surgeon German Ochoa has revealed that the retired forward has no cartilage left in either knee after the footage was posted online.

"I know Diego going back to 2004 when I operated on his right knee, 27 days after he said goodbye to football at the Bombonera," Ochoa was quoted as saying by Spanish newspaper Marca.

"Then in June before the World Cup we did a basic treatment so that he could carry out his activities in Russia in the best way possible.

"Maradona has severe osteoarthritis in his two knees and has no cartilage left, the bones rub together and it is a serious problem as it causes a lot of pain, inflammation and difficulty to move.

"The solution is to operate and put prostheses.”

Poor guy. It’s hard not to feel for him.

"It would not get to the point that Diego could not walk, it would not get that bad,” Ochoa added. “Advances in technology offer a solution and the most prudent and intelligent option is to operate."

All lovers of football will surely be hoping to see him pain-free as soon as possible.