[Radionuclide scan with TC-99m-tin colloid in the evaluation of orthopedic implant infections].

We have studied 26 patients (32-77 years old, 16 females) with suspicion of joint arthroplasty infection: 11 total hip replacements, 12 total knee replacements and 3 osteosinthesys. A bone scintigraphy with MDP-99mTc, a scintigraphy with HMPAO-WBC and a scintigraphy with 99mTc-stannous colloid were made in all patients. The final diagnostic was based in joint cultures and clinic and radiologic evolution of the patients. The earliest phase of the bone scintigraphy was positive in 18 patients. The later phase was positive in all them. The WBC was positive in 20 out of 26 patients. The bone marrow scintigraphy showed a congruent pattern with WBC in 18 patients (17 infected and 1 without infection). The other ones (8 patients) showed an incongruent pattern (7 with infection and 1 without it). The results show that the bone marrow scintigraphy with 99mTc-stannous colloid improves the accuracy of the diagnostic of bone prosthesis infection and should be included into the diagnosis protocol of this disease.