Browsing by Author "Pucar, Dragan (6603430034)"

Background/Aim. Although the number of new primary implantation of hip and knee prostheses every year increases, the rate of failed arthroplasty is nearly the same. The main question is whether it is an aseptic instability or instability caused by infection. The aim of this preliminary study was an attempt with combined 99mTc-ciprofloxacin and 99mTc-methylene diphosphonate (MDP) bone scintigraphy to improve diagnostic accuracy in the differentiation of hip and knee prosthesis aseptic loosening and periprosthetic joint infection. Methods. Inclusion criteria of patients for this study were based on suspected periprosthetic joint infection: painful prosthetic joint, restricted joint movements and increased value of erythrocyte sedimentation rate or levels of C-reactive protein. We examined 20 patients with implanted 14 hip and 6 knee prosthesis. All patients also underwent plain radiography of suspected joint. In all patients, three-phase 99mTc-MDP bone scintigraphy was performed. Three to five days after the bone scan, we performed scintigraphy using 99mTc-ciprofloxacin with the calculation of accumulation index. Periprosthetic joint infection was confirmed on the basis of microbiological findings. Results. Periprosthetic joint infection was confirmed in fourteen of twenty observed joints, in five of them the aseptic loosening was present and in one patient’s symptoms were not related to the prosthesis (poor biomechanics of prosthetic joints caused by weaknesses of muscle). Estimated sensitivity/specificity for 99mTc-MDP bone scintigraphy alone were 100/17%; for 99mTc-ciprofloxacin scintigraphy were 85,7/100%. Sensitivity and specificity were 92,3% and 83,3%, respectively for results obtained with combined assessment by both methods. Our study confirmed the high negative predictive value of 99mTc-MDP bone scan. The negative result of bone scan virtually excludes the possibility of periprosthetic infection. On the other hand, positive findings of 99mTc-MDP scintigraphy cannot with certainty confirm the infection. Conclusion. Combined 99mTc-MDP scintigraphy with 99mTc-ciprofloxacin scintigraphy significantly increases the ability of differentiation of aseptic loosening from periprosthetic joint infection. © 2017, Institut za Vojnomedicinske Naucne Informacije/Documentaciju. All rights reserved.

Background/Aim. In the last five decades primary hip and knee arthroplasty is the most common and effective surgical intervention worldwide. Infection, although unfrequented, is the most serious complication. Nuclear medicine imaging, not affected by metallic hardware, is the current imaging modality of choice for the evaluation of suspected joint replacement infection. The aim of this study was to estimate the diagnostic accuracy of three phase 99m technetium methylene diphosphonate (99mTc-MDP) bone scintigraphy in periprosthetic hip and knee joint infection. Methods. Inclusion criteria of patients in the study were suspected knee or hip periprosthetic joint infections. In this study, we examined 45 patients (14 men and 31 women) with 39 hip and 24 knee prosthesis (total 63). In all patients, three-phase bone scintigraphy was performed after intravenous application of 555 MBq of 99mTc-MDP. The final confirmation of infection was microbiological or pathohistology finding. Results. Infection was confirmed in 29 prosthetic joints, in 13 (44.8%) knee and 16 (55.2%) hip joints while there was no infection in 34 prosthetic joints. The connection of different modalities of negative and positive findings 99mTc-MDP three-phase bone scintigraphy with the final confirmation of infection showed a high statistical significance (p < 0.001). Three phase bone scintigraphy showed a high sensitivity of 90% but a modest specificity of 69.7% in the detection of periprosthetic infection with the diagnostic accuracy of 79%. The calculated positive predictive value was 73% but the negative predictive value was high 89%. Our results of three-phase bone scintigraphy with calculated sensitivity, specificity and diagnostic accuracy of 79% are in consent with the majority of published studies, or even slightly better. Conclusion. Bone scintigraphy is sensitive in the diagnosis of periprosthetic infection but insufficiently specific. In the detection of periprosthetic infections three-phase bone scan can be used as a diagnostic method of the first line only aimed at its exclusion. The only reasonable use of bone scintigraphy is in combination with other radionuclide methods with high specificity. © 2017, Institut za Vojnomedicinske Naucne Informacije/Documentaciju. All Rights Reserved.