True or False: During explanting process, when removing the trunion on the Univers II or Apex stems, it's necessary to remove both the inferior and superior screws to disengage from stem.

• A. True
• B. False
• C. Cannot be determined
• D. Not applicable

Answer: (B)

In modular neck–stem designs, the neck is secured to the trunnion with locking screws, and removing those screws frees the neck from the stem. For Univers II and Apex stems, you generally release the locking action by backing out the inferior screw; once that clamp is released, the neck can be disengaged from the trunnion with the appropriate controlled force. The superior screw is not required to be removed to achieve disengagement, and leaving it in place does not prevent the trunnion from separating after the inferior screw is loosened. Therefore, it’s not necessary to remove both screws to detach the trunnion. If the neck won’t disengage after the inferior screw is released, you would follow the instrument protocol for additional steps, but removing both screws is not the standard requirement.