Basu et al [81] found the sensitivity, specificity, PPV, and NPV of FDG-PET in knee prostheses were 94.7%, 88.2%, 69.2%, and 98.4%, respectively, in 87 patients with knee prostheses suspected of being either infected or experiencing noninfectious loosening. Van Acker et al [82] investigated the use of FDG-PET in combination with bone scans and showed no advantage over HMPAO-labeled WBC and bone scans. Comparison of FDG-PET with In-111- labeled leukocyte/Tc-99m-labeled sulfur colloid marrow imaging showed that FDG-PET was less accurate than the leukocyte/marrow scans and could not replace that combination of tests [69]. Fluoride PET/CT Whole Body There is insufficient evidence to support the use of fluoride PET/CT for the initial evaluation of TKA. Imaging After Total Knee Arthroplasty as a month may be necessary for cultures of aspirated fluid to become positive [30]. Weekly repeat aspirations may be needed if the first aspiration is negative and clinical suspicion for infection remains high. Even with a negative preoperative aspiration, intraoperative tissue may indicate infection. Bernard [50], after literature review and a multicenter trial, advocated CRP and joint aspiration as the best tools for diagnosing prosthetic joint infection. When the CRP level is >10 mg/L, repeat joint aspiration or biopsy is suggested. Della Valle [90] also found the combination of ESR and CRP to be a good screening tool for infection, with only one infected knee having negative results on both tests. These authors suggest preoperative aspiration if the ESR or CRP is elevated or if clinical suspicion is high, combined with intraoperative frozen section analysis of the periprosthetic synovial tissue [90].
Imaging After Total Knee Arthroplasty. Basu et al [81] found the sensitivity, specificity, PPV, and NPV of FDG-PET in knee prostheses were 94.7%, 88.2%, 69.2%, and 98.4%, respectively, in 87 patients with knee prostheses suspected of being either infected or experiencing noninfectious loosening. Van Acker et al [82] investigated the use of FDG-PET in combination with bone scans and showed no advantage over HMPAO-labeled WBC and bone scans. Comparison of FDG-PET with In-111- labeled leukocyte/Tc-99m-labeled sulfur colloid marrow imaging showed that FDG-PET was less accurate than the leukocyte/marrow scans and could not replace that combination of tests [69]. Fluoride PET/CT Whole Body There is insufficient evidence to support the use of fluoride PET/CT for the initial evaluation of TKA. Imaging After Total Knee Arthroplasty as a month may be necessary for cultures of aspirated fluid to become positive [30]. Weekly repeat aspirations may be needed if the first aspiration is negative and clinical suspicion for infection remains high. Even with a negative preoperative aspiration, intraoperative tissue may indicate infection. Bernard [50], after literature review and a multicenter trial, advocated CRP and joint aspiration as the best tools for diagnosing prosthetic joint infection. When the CRP level is >10 mg/L, repeat joint aspiration or biopsy is suggested. Della Valle [90] also found the combination of ESR and CRP to be a good screening tool for infection, with only one infected knee having negative results on both tests. These authors suggest preoperative aspiration if the ESR or CRP is elevated or if clinical suspicion is high, combined with intraoperative frozen section analysis of the periprosthetic synovial tissue [90].