Police are investigating a serious assault which took place in Sark on Friday night.
It happened in the Bel Air pub around midnight.
The victim suffered what police have described as a 'significant knee injury', requiring an urgent medical evacuation to the PEH to be operated on.
Officers deployed to Sark on Sunday arrested a 20-year-old man who was transferred with the officers back to Guernsey.
Police say there were plenty of people in the pub throughout the evening, and they want to hear from anyone who has information.
If you can help, you're asked to call Guernsey Police on on 725111 or Crimestoppers on 0800 555 111.

Guernsey primary school gets daily vegetable tasters
Storm Benjamin dramatically ends Guernsey's dry spell
Tireless Guernsey fundraiser "re-energised" by awards evening
Deputy Neil Inder is Guernsey's new Planning Authority president
Red warning issued for severe winds
Spike in 'sextortion' cases targeting 14 to 30-year-olds in Guernsey
Guernsey cemetery removes bins due to rising costs
Risk of WW2 bombs buried in Guernsey field to be assessed