technetium-tc-99m-medronate and Foreign-Body-Migration

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.

Topics: Adult; Aged; Arthritis, Rheumatoid; Data Interpretation, Statistical; Female; Femur; Foreign-Body Migration; Humans; Knee Joint; Knee Prosthesis; Male; Middle Aged; Osteoarthritis; Photogrammetry; Prospective Studies; Radionuclide Imaging; Technetium Tc 99m Medronate; Time Factors

To establish the time-course of bone scans after bipolar hip arthroplasty (BHA) bone scanning was performed before and after surgery in 22 hips. The influence of migration of the outer head into the acetabulum on the time-course of bone scans was examined by analyzing the relationship between the uptake of radioisotope and the magnitude of migration. The bone scans were quantitatively analyzed by single photon emission computed tomography (SPECT) on the basis of the ratio of radioactivity at the acetabulum to that in the anterior superior iliac spine (ASIS). The increased radionuclide activity decreased exponentially to a baseline with time after surgery. The postoperative uptake ratio could be expressed as a function of the preoperative uptake ratio and the postoperative length of time. The regression slope representing the decreasing rate of uptake showed no significant differences between two groups divided by the magnitude of migration of the outer head. Migration of the outer head was considered not to influence the time-course of the bone scans.

Topics: Adult; Aged; Aged, 80 and over; Evaluation Studies as Topic; Female; Foreign-Body Migration; Hip Prosthesis; Humans; Male; Middle Aged; Osteoarthritis, Hip; Technetium Tc 99m Medronate; Tomography, Emission-Computed, Single-Photon