THE ROLE OF ASPIRATION AND CONTRAST-ENHANCED ARTHROGRAPHY IN EVALUATING THE UNCEMENTED HIP-ARTHROPLASTY

OBJECTIVE. The purpose of this study was to determine the value of asp iration and contrast-enhanced arthrography in evaluating uncemented to tal hip arthroplasty components. A retrospective study was performed t o determine the sensitivity, specificity, and accuracy of these proced ures. MATERIALS AND METHODS. Preoperative aspiration of the hip joint and contrast-enhanced arthrography were performed by a skeletal radiol ogist in 33 hips with uncemented components before exploration or revi sion, In one patient, the hip aspiration yielded grossly purulent flui d and arthrography was not performed. Twenty-one uncemented acetabular components and 29 uncemented femoral components were evaluated by art hrography. The aspiration of the hip provided fluid for culture in 33 hips; in one hip, no fluid could be obtained. RESULTS. A preoperative diagnosis of infection based on growth on solid media was made in five hips (15%). An additional infection was determined to be present in t he hip in which no fluid was obtained when purulent fluid was found at operation. On the basis of the operative findings, contrast-enhanced arthrography of the 21 acetabular components had a sensitivity of 50%, a specificity of 77%, and an accuracy of 68%. Arthrography of the 29 femoral components had a sensitivity of 63%, a specificity of 64%, and an accuracy of 63%. CONCLUSION. Aspiration of the hip joint before re vision of uncemented hip arthroplasties was valuable because the diagn osis of infection was made preoperatively in five of six hips. However , contrast-enhanced arthrography was not valuable, with a low sensitiv ity and specificity for both uncemented acetabular and uncemented femo ral components. Only a preoperative aspiration of the hip joint is rec ommended before revision of uncemented components.