Painful knee joint prostheses: evaluation for loosening by combined radionuclide arthrography and transmission imaging.

UNLABELLED: Interpretation of radionuclide arthrograms (RNA) of the knee after total knee joint replacement (TKR) may be difficult because of the lack of sufficient anatomic reference information. Additional transmission images may provide the necessary reference information required for correct interpretation of RNA of the knee.

METHODS

Tc-99m tin colloid (20 MBq) RNA was combined with cobalt-57 transmission imaging in six patients with painful TKRs in whom loosening of the TKR was suspected. Knee surgery was then performed on these six cases.

RESULTS

RNA correctly detected loosening of the tibial component in five of six cases, but did not detect loosening of the femoral component in any of three cases.

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.