Exegesis:

kai epataxen heis tis ex autōn ‘and (indeed) one of them struck…,’ without waiting for Jesus’ answer to the question of v. 49. heis tis is equivalent to heis alone.

tou archiereōs ton doulon ‘the slave of the high priest.’ tou archiereōs is emphatic by virtue of its position before ton doulon.

kai apheilen to ous autou to dexion ‘and cut off his right ear.’ aphaireō lit. ‘to take away’ is used here in a more specific meaning, i.e. ‘to cut off,’ ‘to shear off.’

Translation:

For slave see on 7.2, for high priest see references on 3.2.

His right ear. In several languages one has to say, ‘his ear at the right side.’

Quoted with permission from Reiling, J. and Swellengrebel, J.L. A Handbook on the Gospel of Luke. (UBS Handbook Series). New York: UBS, 1971. For this and other handbooks for translators see here . Make sure to also consult the Handbook on the Gospel of Mark for parallel or similar verses.