Imaging After Total Hip Arthroplasty US Hip US can be used to detect ARMD pseudotumors (solid or cystic) and other findings seen with ARMD such as joint effusions, bursal collections, capsular and bursal thickening, and synovitis [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. 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]. In a series of 82 hips (82 patients) undergoing revision of MoM prostheses, Lainiala et al [51] found a sensitivity of 83% and specificity of 92% for US examination of pseudotumors in the trochanteric region and a sensitivity of 79% and specificity of 94% for identifying pseudotumors in the iliopsoas region. Matharu et al [66] studied a series of 40 MoM hip resurfacing arthroplasties in 39 patients undergoing revision surgery who had preoperative imaging with both US and MARS-MRI. Comparison with operatively identified pseudotumors showed US to have a sensitivity of 90.9% and a specificity of 42.9% compared with an MRI sensitivity of 93.9% and specificity of 57.1%. The PPV was similar (88.2% US, 91.2% MRI), but the NPV was higher for MRI (66.7% on MRI, 50.0% for US) [66]. Combined US and MARS-MRI studies: Comparison to surgical results suggests combined 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 [41,52]. Variant 7: Hip arthroplasty patient with trochanteric pain. Suspect abductor injury, or trochanteric bursitis, or other soft tissue abnormality. Additional imaging following radiographs. Postoperative greater trochanter pain may be due to greater trochanteric bursitis, or other etiologies such as gluteus minimus or medius tendinitis, or tears or avulsion [73].
Imaging after Total Hip Arthroplasty PCAs. Imaging After Total Hip Arthroplasty US Hip US can be used to detect ARMD pseudotumors (solid or cystic) and other findings seen with ARMD such as joint effusions, bursal collections, capsular and bursal thickening, and synovitis [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. 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]. In a series of 82 hips (82 patients) undergoing revision of MoM prostheses, Lainiala et al [51] found a sensitivity of 83% and specificity of 92% for US examination of pseudotumors in the trochanteric region and a sensitivity of 79% and specificity of 94% for identifying pseudotumors in the iliopsoas region. Matharu et al [66] studied a series of 40 MoM hip resurfacing arthroplasties in 39 patients undergoing revision surgery who had preoperative imaging with both US and MARS-MRI. Comparison with operatively identified pseudotumors showed US to have a sensitivity of 90.9% and a specificity of 42.9% compared with an MRI sensitivity of 93.9% and specificity of 57.1%. The PPV was similar (88.2% US, 91.2% MRI), but the NPV was higher for MRI (66.7% on MRI, 50.0% for US) [66]. Combined US and MARS-MRI studies: Comparison to surgical results suggests combined 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 [41,52]. Variant 7: Hip arthroplasty patient with trochanteric pain. Suspect abductor injury, or trochanteric bursitis, or other soft tissue abnormality. Additional imaging following radiographs. Postoperative greater trochanter pain may be due to greater trochanteric bursitis, or other etiologies such as gluteus minimus or medius tendinitis, or tears or avulsion [73].