The value of skeletal scintigraphy in predicting the need for revision surgery in total knee replacement.

We have reviewed the results of 99mtech-netium-methylene diphosphonate (Tc-MDP) bone scintigrams performed on patients following total knee arthroplasty. In addition, 67gallium (Ga) citrate scintigrams were carried out sequentially on 29 patients. Three groups of patients were identified: those with asymptomatic knees (undergoing scans for other reasons); those with aseptic or septic loosening; and those with pain without radiologic evidence of loosening. There was good correlation between the results of the scans and the final outcome. We conclude that sequential 99mTc-MDP and 67Ga citrate scintigrams are useful for demonstrating the presence of aseptic and septic loosening in knee prostheses, and pain with a normal scan appearance is probably not due to loosening or infection.