CT of acetabular fractures: postoperative appearances.

Thirty-one postoperative pelvic computed tomographic (CT) scans in 29 patients studied between 1 day and 7 years after open reduction and internal fixation of acetabular fractures were reviewed. CT was most useful in the immediate postoperative period for detecting residual intraarticular fragments, localizing metallic fixation devices, and assessing the adequacy of reduction. CT scans obtained in the late postoperative period were useful primarily for determining the position and extent of ectopic bone before surgical removal.

Valve dynamics.

Flow between two contiguous elastic sheets (valve leaflets) generates one of two types of behavior. At low pressure differences, e.g.