Williams et al [46] proposed high-resolution US surveillance of all asymptomatic patients with a MoM implant that is known to result in high serum metal ion levels. Low et al [50] prospectively followed 152 asymptomatic MoM hip resurfacing arthroplasties at a mean of 4.3 years using US. Progression of findings occurred in 19%, and new pseudotumors developed in 10%. No asymptomatic hip resurfacing arthroplasty patient with both a normal initial US and low blood metal ions (<2 ug/L) developed pseudotumors within 5 years of initial assessment, and, therefore, they concluded this patient subgroup did not require repeat follow-up within 5 years [50]. Comparison of US with MRI: A summary of studies comparing US to MARS-MRI as the reference standard for detecting ARMD shows sensitivities for US of 69% to 100% and specificities of 83% to 96% [36]. Kwon et al [52] found that US was valid and useful for detecting interval changes in lesion size and grade in comparison with MARS-MRI. Combined US and MARS-MRI studies: Comparison to surgical results suggests combining US and MARS-MRI improves accuracy. Small numbers of lesions detected on US are not visible on MRI and some lesions seen on MRI are not apparent on US [36,41,52]. Variant 2: Symptomatic patient with hip prosthesis. Initial imaging. Bone Scan Hip There is insufficient evidence to support the use of bone scan of the hip as the initial imaging procedure in the evaluation of the symptomatic hip arthroplasty. Bone Scan with SPECT or SPECT/CT Hip There is insufficient evidence to support the use of bone scans with SPECT or SPECT/CT of the hip as the initial imaging procedure in the evaluation of the symptomatic hip arthroplasty. Imaging After Total Hip Arthroplasty CT Hip There is insufficient evidence to support the use of CT of the hip as the initial imaging procedure in the evaluation of the symptomatic hip arthroplasty.
Imaging after Total Hip Arthroplasty PCAs. Williams et al [46] proposed high-resolution US surveillance of all asymptomatic patients with a MoM implant that is known to result in high serum metal ion levels. Low et al [50] prospectively followed 152 asymptomatic MoM hip resurfacing arthroplasties at a mean of 4.3 years using US. Progression of findings occurred in 19%, and new pseudotumors developed in 10%. No asymptomatic hip resurfacing arthroplasty patient with both a normal initial US and low blood metal ions (<2 ug/L) developed pseudotumors within 5 years of initial assessment, and, therefore, they concluded this patient subgroup did not require repeat follow-up within 5 years [50]. Comparison of US with MRI: A summary of studies comparing US to MARS-MRI as the reference standard for detecting ARMD shows sensitivities for US of 69% to 100% and specificities of 83% to 96% [36]. Kwon et al [52] found that US was valid and useful for detecting interval changes in lesion size and grade in comparison with MARS-MRI. Combined US and MARS-MRI studies: Comparison to surgical results suggests combining US and MARS-MRI improves accuracy. Small numbers of lesions detected on US are not visible on MRI and some lesions seen on MRI are not apparent on US [36,41,52]. Variant 2: Symptomatic patient with hip prosthesis. Initial imaging. Bone Scan Hip There is insufficient evidence to support the use of bone scan of the hip as the initial imaging procedure in the evaluation of the symptomatic hip arthroplasty. Bone Scan with SPECT or SPECT/CT Hip There is insufficient evidence to support the use of bone scans with SPECT or SPECT/CT of the hip as the initial imaging procedure in the evaluation of the symptomatic hip arthroplasty. Imaging After Total Hip Arthroplasty CT Hip There is insufficient evidence to support the use of CT of the hip as the initial imaging procedure in the evaluation of the symptomatic hip arthroplasty.