"Prior inconsistent statement" is a general exception to the hearsay rule. It allows entry into evidence of sworn testimony taken outside of court that would otherwise be excluded under the hearsay rule where a witness gives sworn testimony in court that is at odds with previous testimony. As a rule, it will only be admitted under cross-examination or with a hostile witness. It would include such pre-trial testimony such as:

However, only the relevant portion of the pre-trial testimony can be admitted under this rule. It is not an open door to allow all pre-trial testimony into evidence. It also generally prohibits the introduction of pre-trial testimony in lieu of examination-in-chief.

The existence of this rule is to make pre-trial discovery a useful exercise. It prevents a party from taking one position prior to trial and another position at trial. In addition, it encourages full disclosure at the discovery stage to aid settlement as answers given at the discovery stage may not be used directly at trial, allowing trial counsel to avoid matters that don't support their client's case.