Howley has had many highlights in his career including representing Wales 59 times, 22 as captain. However, from a London Wasps' perspective, he will always be the scrumhalf who scored 'that try' during the Heineken Cup final at Twickenham, something that will be etched into the Wasps' history books for eternity.
Howley first suffered the Scaphoid injury during Wasps' Heineken Cup pool match against Perpignan on February 1 2004. However, he completed the season, winning two trophies, before undergoing an operation in June to correct it. He was initially expected to return to playing in November but at the beginning of October was told that the fracture had not made union.
Following professional consultation it then became apparent that the pin inserted in his Scaphoid bone had not engendered fusion in the fracture. Scaphoid injuries, which can often go undetected until the pain becomes too much, are notoriously slow to heal.
Howley said: "It's a very sad and scary feeling to be told that your rugby career is over. I had high hopes of returning to Wasps and even pushing for a place on the Lions squad, but unfortunately it's not to be. I remember playing my first few games as a youngster in Wales and wondering how long my career would be and when it would all end - now I know that answer.
"I didn't think a wrist injury would be the end of me but sadly it is. I've had a fantastic career, both at club level and internationally and would like to take this opportunity to thank everyone involved. I've met so many people along the way and made new friends.
"Yes I am sad, but from the negatives there are always positives and I can now spend extra time with my family."
Wasps Director of Rugby, Warren Gatland said: "Rob came here in the summer of 2002 and brought something special with him. His service to the club was outstanding and something we will always be grateful for. I would like to thank him for everything he's done and wish him well for the future. As we always say, Once a Wasp, Always a Wasp."
Asked what he might be doing now, Howley added: "I'm not sure, but I would like to give something back to rugby. I have said that I would like to give coaching a go, but starting at the bottom and working my way up. Who knows, but I will still be around the rugby circles."