Low-grade or chronic TKA infections may be difficult to diagnose preoperatively. Duff et al [18] noted that diagnosis of infection was not obvious in 53% of knees before revision arthroplasty. Pain is the most common presenting symptom of infection, but pain is a nonspecific finding [47]. In acute infection, findings such as pain, swelling, warmth, erythema, and fever are common, whereas chronic infections may be manifested by pain alone [44]. Night pain or pain at rest is characteristic of infection, whereas pain on weightbearing is more characteristic of mechanical loosening. Some authors suggest that infection needs to be excluded in all patients with pain persisting >6 months after joint replacement [18]. Imaging After Total Knee Arthroplasty CT Arthrography Knee CT joint arthrography can assess for lucency with contrast accumulation at the bone/cement/hardware interface. These areas of lucency are not specific for infection versus mechanical loosening. CT Knee With IV Contrast CT has a limited role in the workup of periprosthetic infection. CT with IV contrast could help demonstrate periprosthetic fluid collections and fistulae. Advances in metal artifact reduction may expand the potential role of CT. CT Knee Without and With IV Contrast CT has a limited role in the workup of periprosthetic infection. Noncontrast CT can demonstrate the size and extent of osteolysis, periprosthetic lucencies, intraosseous or soft-tissue gas, and reactive bone formation that might not be evident on radiographs [20,67]. CT with IV contrast could help demonstrate periprosthetic fluid collections and fistulae. Advances in metal artifact reduction may expand the potential role of CT. CT Knee Without IV Contrast CT has a limited role in the workup of periprosthetic infection. Noncontrast CT can demonstrate the size and extent of osteolysis, periprosthetic lucencies, intraosseous or soft-tissue gas, and reactive bone formation that might not be evident on radiographs [20,67].
Imaging After Total Knee Arthroplasty. Low-grade or chronic TKA infections may be difficult to diagnose preoperatively. Duff et al [18] noted that diagnosis of infection was not obvious in 53% of knees before revision arthroplasty. Pain is the most common presenting symptom of infection, but pain is a nonspecific finding [47]. In acute infection, findings such as pain, swelling, warmth, erythema, and fever are common, whereas chronic infections may be manifested by pain alone [44]. Night pain or pain at rest is characteristic of infection, whereas pain on weightbearing is more characteristic of mechanical loosening. Some authors suggest that infection needs to be excluded in all patients with pain persisting >6 months after joint replacement [18]. Imaging After Total Knee Arthroplasty CT Arthrography Knee CT joint arthrography can assess for lucency with contrast accumulation at the bone/cement/hardware interface. These areas of lucency are not specific for infection versus mechanical loosening. CT Knee With IV Contrast CT has a limited role in the workup of periprosthetic infection. CT with IV contrast could help demonstrate periprosthetic fluid collections and fistulae. Advances in metal artifact reduction may expand the potential role of CT. CT Knee Without and With IV Contrast CT has a limited role in the workup of periprosthetic infection. Noncontrast CT can demonstrate the size and extent of osteolysis, periprosthetic lucencies, intraosseous or soft-tissue gas, and reactive bone formation that might not be evident on radiographs [20,67]. CT with IV contrast could help demonstrate periprosthetic fluid collections and fistulae. Advances in metal artifact reduction may expand the potential role of CT. CT Knee Without IV Contrast CT has a limited role in the workup of periprosthetic infection. Noncontrast CT can demonstrate the size and extent of osteolysis, periprosthetic lucencies, intraosseous or soft-tissue gas, and reactive bone formation that might not be evident on radiographs [20,67].