By Kieran King Arsenal boss Mikel Arteta has a selection dilemma on his hands for the trip to Sheffield United tonight because Thomas Partey is finally back fit and available. Partey started the first four matches of the season before picking up a groin problem against Fulham at the end of August. He missed just over a month of action and returned to face Manchester City on October 8, but that proved to be his final appearance before suffering a hamstring issue. And now the 31-year-old has recovered and is back in contention for the Gunners as they prepare for the business end of the campaign….