Sentence:  Then Romany went down, then we fell together, and the chaps separated us. I got another knock-down blow in, and was beginning to enjoy the novelty of it, when Romany staggered and limped. / ‘I've done,' he said. ‘I've <WSD>twisted</WSD> my ankle.' He'd caught his heel against a tuft of grass. 
Meaning of the word marked with <WSD> tags:  To injure (a body part) by bending it in the wrong direction.