Oscar Pistorius' famous 'blade runner' prosthetic legs no longer fit him after his years in prison – as the 'overweight' Paralympian fears he will never be able to run properly again

Oscar Pistorius' famous 'blade runner' prosthetic legs no longer suit him after years of inactivity in prison – and he fears he will never be able to run properly again.

The lack of daily running while in prison means the disgraced athlete's legs have shrunk and are no longer compatible with the signature custom-made blades he wore during the Paralympic Games that made him world famous.

The 38-year-old, who shot dead model Reeva Steenkamp on Valentine's Day 2013, contacted doctors while in Pretoria's Atteridgevale prison because he was concerned about muscle deterioration.

Pistorius had both feet amputated when he was eleven months old due to a congenital defect. At birth, both feet and both fibula bones were missing.

Dr. Gerald Versfeld, the orthopedic surgeon who performed the double amputation, went to see the killer in prison to help fit new prosthetics after he complained that the prosthetics he entered prison with were uncomfortable and no longer fit.

It was found that Pistorius, who was released on parole on January 5 and who in his prime stood 6 feet tall on his artificial limbs, had experienced a reduction in the length of his remaining thighs.

'They had simply shrunk or withered away because he could no longer run as far or as far as when he was competing or when he was a free man,' a source told MailOnline.

'His muscles are much weaker now. He has been given new prosthetics to replace his old ones, which no longer fit,” the prison source said.

“He's trying to adapt, but he's afraid he'll never be able to run like he used to again.”

Pistorius was released after serving half of his 13-year, 5-month prison sentence for Reeva's murder.

But being a shrinking man is not the only ailment facing the athlete who has competed in both the 2012 London Paralympic Games and the regular Olympic Games.

He has become a chain smoker, has gained weight and is becoming paranoid about being harmed or facing public anger.

He suffers from anxiety and has not left his uncle Arnold's country house since he was smuggled out of prison, remaining at the house in Waterkloof.

The source said he had locked himself in his bedroom, reading his Bible, playing video games and watching Premier League football on his television.

But he has received loyal support from his sister Aimee and the siblings have started laughing and joking in Afrikaans.

Asked about his incarceration since his release, Dr Versfeld told MailOnline: 'I think it will take a long time before he can escape from his uncle's house.

'Maybe there are conditions that keep him at home.

'But I don't think he's ready to face the world. He's been in a pretty terrible environment for a while now. He spent eight years in prison.”

It is also reported that underworld figures were keen to take revenge on Pistorius for the slaughter of Reeva, whose star was rising and expected to become a popular TV personality.

Alan Retief of Waterkloof, who presented Pistorius with flowers upon his release, said: 'He should be right to be scared because he hasn't been in public for a long time.

'The public perception of him has changed. He was a hero and now he's a convicted murderer. He needs time, a lot of time to help him.'

Pistorius must undergo “anger management therapy” for the remaining five years of his sentence while on parole and is not allowed to drink alcohol, use drugs or handle weapons.

He must live with his uncle until December 2029, after which his sentence expires.

But Mr Retief added: 'It has been a great downfall for Oscar, but many people in this area still like him and are not convinced that he intended to shoot Reeva and that he genuinely believed it was there was an intruder in his house.'