PAINFUL KNEE-JOINT PROSTHESES - EVALUATION FOR LOOSENING BY COMBINED RADIONUCLIDE ARTHROGRAPHY AND TRANSMISSION IMAGING

Interpretation of radionuclide arthrograms (RNA) of the knee after tot al knee joint replacement (TKR) may be difficult because of the lack o f sufficient anatomic reference information. Additional transmission i mages may provide the necessary reference information required for cor rect interpretation of RNA of the knee. Methods: Tc-99m tin colloid (2 0 MBq) RNA was combined with cobalt-57 transmission imaging in six pat ients with painful TKRs in whom loosening of the TKR was suspected. Kn ee surgery was then performed on these six cases. Results: RNA correct ly detected loosening of the tibial component in five of six cases, bu t did not detect loosening of the femoral component in any of three ca ses. Conclusion: RNA combined with transmission imaging is recommended for detection of loosening of the tibial component of a TKR. RNA may not be of value for detecting loosening of the femoral component.