A Hamilton police officer who was seriously injured when a teenager rammed a stolen car into his patrol vehicle is finally back at work after a 14-month recovery.

Myles O'Donnell's femur was broken in four places when the 16-year-old unlicensed driver "T-boned" the car the constable was driving during the November 2010 pursuit in Hamilton.

Paramedics told the 36-year-old that without a side airbag in the driver's door, which took the brunt of the impact, Mr O'Donnell would probably have died.

"It's pretty scary being on the other side of it," Mr O'Donnell said.

"I've been to that many accidents and seen that many people get cut out of cars but it was a little bit different having it done to yourself."

Mr O'Donnell and his police partner, who was unhurt, were trapped in the car for at least 20 minutes, during which time they made a frantic phone call to his girlfriend to tell her of the crash.

At Waikato Hospital he had 4 hours of surgery, with a metal rod and four screws inserted in his right leg to hold it together.

That was followed by 12 days in hospital, three months on crutches barely able to walk, four months of intensive physiotherapy, further surgery to remove two screws, and a gradual return to work starting with two hours a day behind a desk.

Yesterday the police officer donned his uniform again and hit the beat for the first time since that day.

Mr O'Donnell was pleased to be back and said he never considered giving up the job. "I just want to get back into it. But probably my first pursuit will be a little bit testing."

The incident was one of 168 crashes in the Waikato in 2010 where 208 people suffered serious injuries.

Waikato Hospital trauma specialist Dr Grant Christey said each year it treated about 250 people suffering major injuries from a road crash, and a significant factor in the situation was poor decision-making.

"Drinking and driving, taking drugs, or driving while fatigued which can all be contributors," Dr Christey said.

People would be surprised at the high cost of road accidents, the specialist said.

"After the scene is cleared up and the injured taken to hospital, the average cost of a major trauma case is $3000 to $6000 per day, and an average 14-day stay in intensive care is about $50,000 before you factor in additional surgery, nursing care and rehabilitation."

Mr O'Donnell's rehabilitation included support from the police to employ a part-time home helper, an advanced physiotherapy programme, and his job held open, while the written-off patrol car cost about $50,000 to replace. On top of this he would probably need a new hip in 10 years because of damage caused by the breaks.

District road policing manager Inspector Leo Tooman said advances in medical technology meant more people were surviving serious crashes with potentially life-altering injuries.

Although the teenage driver was sentenced to six months' imprisonment, Mr O'Donnell said: "Ironically, it was me that ended up with the longer sentence."

By Natalie Akoorie Email Natalie