NUCLEAR ARTHROGRAPHY - COMBINED SCINTIGRAPHIC AND RADIOGRAPHIC PROCEDURE FOR DIAGNOSIS OF TOTAL HIP-PROSTHESIS LOOSENING

Radiographic arthrography and bone scintigraphy are common diagnostic procedures used for evaluating total hip prostheses. In this study, bo th techniques are combined, and nuclear contrast imaging (nuclear arth rography) is added, The efficacy of the procedures is evaluated. Metho ds: After intravenous injection of Tc-99m-methylene diphosphonate (MDP ), standard radiographic arthrography was performed in 105 patients (1 07 prostheses). The radiographic contrast medium was mixed with insolu ble In-111-colloid (5 MBq/20 mi). After completion of the radiographic arthrography, nuclear arthrography was performed, and multiple-view d ual-isotope images (In-111, 247-keV peak only) were recorded. Images w ere interpreted by superposition of the In-111 image and the correspon ding Tc-99m-MDP image, the latter serving as a landmark for the positi on of the prosthesis and osseous structures. Findings at surgery were used as the gold standard. Results: In both cemented and uncemented ac etabular and femoral components, nuclear arthrography performed better than or equal to radiographic arthrography (70%-90% and 60%-75%, resp ectively). Nuclear arthrography had higher diagnostic accuracy than Tc -99m-MDP images alone. Conclusion: Nuclear arthrography is a sensitive technique for detection of loosening of prostheses, offering added va lue over radiographic arthrography and bone scanning alone, especially for evaluation of the femoral component. Radiographic arthrography re mains necessary not only for adequate deposition of contrast agents bu t also for detailed evaluation of osseous structures.