Storm Over Warlock by Andre Norton

"Well, it works as good as new. " Shann held his hand and arm out into the full path of the sun. He had just stripped off the skin-case bandage, to show the raw seam of a half-healed scar, but as he flexed muscles, bent and twisted his arm, there was only a small residue of soreness left.

"Now what, or where? " he asked Thorvald with some eagerness. Several days' imprisonment in this room had made him impatient for the outer world again. Like the officer, he now wore breeches of the green fabric, the only material known to the Wyverns, and his own badly worn boots. Oddly enough, the Terrans' weapons, stunner and knife, had been left to them, a point which made them uneasy, since it suggested that the Wyverns believed they had nothing to fear from clumsy alien arms.