Tierney, 24, suffered the injury during a training session last week and missed Monday's 3-0 defeat at Crystal Palace.

He has played 22 league games this season for Arsenal, who sit fifth in the table, outside the Champions League places on goal difference.

The need for surgery, after consultation with a specialist, also casts doubt on Tierrney's availability for Scotland's World Cup qualification play-off against Ukraine in June.

Arsenal said "a clearer understanding will be established on his recovery timescale" post-surgery, but they expected him to miss the remainder of the campaign.

Meanwhile, fellow Gunners defender Takehiro Tomiyasu should resume training in a fortnight after two months out with a calf injury.

Midfielder Thomas Partey, however, aggravated a thigh problem in the loss at Selhurst Park and will be assessed before Brighton's visit to Emirates Stadium on Saturday.