Radionuclide arthrography and transmission imaging for assessment of painful hip prostheses.

Abstract

Interpretation of the radionuclide hip arthrogram may present difficulty because of a lack of anatomical reference information. Additional transmission images to determine tracer localization may facilitate scan interpretation. Isotope arthrography (20 MBq 99mTc-tin colloid and 57Co transmission imaging) was prospectively performed on 21 patients with painful hip prostheses and suspected stem loosening. The radionuclide arthrogram was positive in 10 patients and negative in 9 patients. Extravasation of tracer, confirmed by transmission images, resulted in two nondiagnostic studies. Surgery was undertaken in 10 patients and loosening was confirmed in 6 patients. In this surgical subgroup, the scan was true-positive in six patients, true-negative in two patients, false-positive in one patient and nondiagnostic in one patient. The combination of radionuclide arthrography and transmission imaging facilitates scan interpretation and is a recommended method for investigating suspected loosening of the femoral stem.