"I'm devastated, I hoped to have a long career and achieve a lot," Martenko told the South Wales Evening Post.

"It's been one problem after another. I had two operations, then it went again and the doctors said I wouldn't be able to lift my arm up if I kept on playing.

"The Ospreys have been brilliant. They did all they could to get me right, but it wasn't to be."

There were big hopes for the Tonyrefail-born second-row when he joined the Ospreys on a development contract from Pontypridd last summer.

But he had already hurt his shoulder while playing for Wales Under-21, and he made just two substitute appearances for the west Glamorgan region, against Leinster and Connacht.

My recovery requires 10 weeks without contact and I am four weeks into it Ospreys hooker Barry Williams

The news of his retirement will cause further worry to the Ospreys' stretched second row resources.

Alun Wyn Jones, Ian Gough, Jon Thomas and Brent Cockbain are likely to be on World Cup duty, along with Ian Evans if he can prove his fitness in time.

Lyndon Bateman's long-standing shoulder injury is expected to keep him out for around the first month of the season, leaving Mike Powell - who is expected to recover from a summer shoulder operation - as the only senior second row.

"In terms of senior locks there is a possibility we could be stretched, but we do have a very promising young lad, Michael Collins, who could do a good job for us if required," said Ospreys director of rugby Kevin Hopkins.

Collins joined Swansea from Maesteg last summer, and has made 16 appearances for the All Whites.

Another talented young Swansea lock, Daniel Lloyd-Jones, is also expected to be considered by the Ospreys.

Meanwhile, shoulder problems have also struck Ospreys hooker Barry Williams, the region's former captain having undergone an operation in the summer.

"If everything goes to plan, I should be available for the opening of the season," said the ex-Lions and Wales man, 33.

"My recovery requires 10 weeks without contact and I am four weeks into it.