Concomitant dislocation and intraarticular foreign body: a rare complication of the Charnley total hip arthroplasty

In the Charnley total hip arthroplasty, periarticular foreign bodies represent potential foci for intraarticular migration at the time of hip dislocation. This complication, although very rare, should be verified radiographically to prevent unsucessful attempts at closed reduction. Although intraarticular radiopaque foreign bodies should be identified on plain radiographs of the hip, intraarticular radiolucent foreign bodies require positive-contrast arthrography for identification. Two illustrative cases are presented.