Fluoroscopy Knee There is no recent evidence supporting the routine use of fluoroscopy for the assessment of aseptic loosening, osteolysis, or instability. Fluoroscopy may be useful to see lucent lines in profile that could be obscured on standard AP radiographs [20,129,130] and can also be useful for demonstrating loosening under real-time manipulation. It can be useful in optimally positioning the joint for detection of radiographic osteolysis [129,130] and facilitates dynamic assessment of the knee under stress. In older studies, this procedure was determined to be useful, but it has been supplanted by other modalities and is now infrequently performed. MRI Knee Without and With IV Contrast MRI without and with IV contrast is not useful for assessment of osteolysis or instability. The use of IV contrast for assessing loosening has not been described. Imaging After Total Knee Arthroplasty MRI Knee Without IV Contrast The literature regarding MRI in the detection of implant loosening is evolving, and the available evidence supports its use. Using metal artifact reduction techniques, Fritz et al [93] described what they posited are distinct appearances for an intact periprosthetic interface (direct contact of the implant or cement with the surrounding bone), a periprosthetic fibrous membrane that indicates limited implant fixation that may or may not progress to loosening (1- to 2-mm thick layer with smooth margins surrounding the prosthesis along the bone interface) and frank bone resorption (a periprosthetic layer >2-mm thick with irregular margins). They reserve the use of the term loosening for cases in which MRI demonstrates circumferential osseous resorption together with signs of implant displacement, subsidence, or rotation. In a study of 116 knees in 114 patients that evaluated the interface type (normal, fibrous membrane, fluid, or osteolysis), percent integration (<33%, 33%-66%, or >66%), and presence of bone marrow edema.
Imaging After Total Knee Arthroplasty. Fluoroscopy Knee There is no recent evidence supporting the routine use of fluoroscopy for the assessment of aseptic loosening, osteolysis, or instability. Fluoroscopy may be useful to see lucent lines in profile that could be obscured on standard AP radiographs [20,129,130] and can also be useful for demonstrating loosening under real-time manipulation. It can be useful in optimally positioning the joint for detection of radiographic osteolysis [129,130] and facilitates dynamic assessment of the knee under stress. In older studies, this procedure was determined to be useful, but it has been supplanted by other modalities and is now infrequently performed. MRI Knee Without and With IV Contrast MRI without and with IV contrast is not useful for assessment of osteolysis or instability. The use of IV contrast for assessing loosening has not been described. Imaging After Total Knee Arthroplasty MRI Knee Without IV Contrast The literature regarding MRI in the detection of implant loosening is evolving, and the available evidence supports its use. Using metal artifact reduction techniques, Fritz et al [93] described what they posited are distinct appearances for an intact periprosthetic interface (direct contact of the implant or cement with the surrounding bone), a periprosthetic fibrous membrane that indicates limited implant fixation that may or may not progress to loosening (1- to 2-mm thick layer with smooth margins surrounding the prosthesis along the bone interface) and frank bone resorption (a periprosthetic layer >2-mm thick with irregular margins). They reserve the use of the term loosening for cases in which MRI demonstrates circumferential osseous resorption together with signs of implant displacement, subsidence, or rotation. In a study of 116 knees in 114 patients that evaluated the interface type (normal, fibrous membrane, fluid, or osteolysis), percent integration (<33%, 33%-66%, or >66%), and presence of bone marrow edema.