Scintimetry after total knee arthroplasty. Prospective 2-year study of 18 cases of arthrosis and 15 cases of rheumatoid arthritis.

33 consecutive patients (18 arthrosis, 15 rheumatoid arthritis), operated on with total knee arthroplasty and randomized to cemented (18 knees) or cementless fixation (15 knees), were investigated with scintimetry 3, 6, 12, and 24 months postoperatively. Migration was evaluated with simultaneous roentgen stereophotogrammetric (RSA) examinations. The scintimetric activity in the ipsilateral femoral diaphysis decreased and the activity in the tibial diaphysis increased during the observation period. Constant and low activity was recorded in front of the femoral component. This region was chosen as a reference. Three months after surgery, high activity was noted under the tibial component in knees with a preoperative varus deformity. After 2 years, the activity had decreased to the same level as in the patients with a valgus deformity. Diagnosis and mode of fixation did not influence the activity. Low postoperative activity was recorded in the tibial metaphyses if no rotatory displacement of the tibial component occurred.