Pistorius, 29, was discharged from the intensive care unit last week, but would remain hospitalized for the next two weeks to undergo additional operations, said family spokeswoman Anneliese Burgess in a statement.
"Carl suffered poly-trauma injuries during the accident," she said. "These included lacerations to his heart and liver and he also went into respiratory failure."
"He has made a miraculous recovery after specialist care intervention and was discharged from ICU late last week," she said.
The crash took place August 1 outside Modimolle, Limpopo, about 130 km (80 miles) north of Pretoria.
Pistorius collided head-on with another car that swerved to the opposite side of the expressway. He and the other driver were both taken to hospital with serious injuries, while two passengers in his car were unhurt.
Barring further complications, Pistorius will be sent to a rehabilitation facility after two weeks to regain his mobility.
"Carl is overwhelmed with gratitude for the support he has received from family, friends and the public," Burgess said.
Pistorius was acquitted on a culpable homicide charge last May related to a 2008 collision that left a woman dead. He had pleaded not guilty to that charge, as was also acquitted on charges of reckless or negligent driving and driving without reasonable consideration for another person using the road.
Oscar Pistorius, meanwhile, is accused of murdering his model girlfriend Reeva Steenkamp on Valentine's Day of last year. A verdict is expected September 11.