The addition of SPECT or SPECT/CT improves diagnosis by allowing more accurate anatomical localization of new bone formation [20]. The specificity of Tc-99m bone scans for periprosthetic fractures increases in older prostheses once postoperative remodeling has decreased. Bone Scan Shoulder There is no relevant literature to support the use of a bone scan as a first-line imaging modality in the acutely symptomatic patient with a primary shoulder arthroplasty. Tc-99m single- and 3-phase bone scans are very sensitive but with low specificity in the diagnosis of post arthroplasty fractures, and imaging findings can overlap with other abnormalities such as loosening and infection [21]. Without a radionuclide angiogram and blood pool phase, the single-phase bone scan will not depict the acute peri fracture hyperemia. Acute periprosthetic fractures are often 3- phase bone scan positive and demonstrate focal increased activity at the fracture site, which decreases over time, corresponding to fracture healing. Fracture hyperemia also typically resolves with the acute/subacute phases. Uncomplicated fracture healing may take up to 2 years before a bone scan normalizes [21,22]. In addition, increased bone uptake can be seen at the site of arthroplasty, related to postoperative bone remodeling for up to 1 year following surgery, which can further complicate matters [21]. The specificity of Tc-99m bone scan imaging for periprosthetic fracture increases in older prostheses once the postoperative remodeling has decreased and stabilized. CT Shoulder CT is not typically ordered for the initial evaluation of a symptomatic shoulder arthroplasty. CT with metal reduction protocol can be subsequently used to detect loosening and to further delineate a periprosthetic fracture seen on radiographs in terms of degree of displacement, extent, and comminution.
Imaging After Shoulder Arthroplasty PCAs. The addition of SPECT or SPECT/CT improves diagnosis by allowing more accurate anatomical localization of new bone formation [20]. The specificity of Tc-99m bone scans for periprosthetic fractures increases in older prostheses once postoperative remodeling has decreased. Bone Scan Shoulder There is no relevant literature to support the use of a bone scan as a first-line imaging modality in the acutely symptomatic patient with a primary shoulder arthroplasty. Tc-99m single- and 3-phase bone scans are very sensitive but with low specificity in the diagnosis of post arthroplasty fractures, and imaging findings can overlap with other abnormalities such as loosening and infection [21]. Without a radionuclide angiogram and blood pool phase, the single-phase bone scan will not depict the acute peri fracture hyperemia. Acute periprosthetic fractures are often 3- phase bone scan positive and demonstrate focal increased activity at the fracture site, which decreases over time, corresponding to fracture healing. Fracture hyperemia also typically resolves with the acute/subacute phases. Uncomplicated fracture healing may take up to 2 years before a bone scan normalizes [21,22]. In addition, increased bone uptake can be seen at the site of arthroplasty, related to postoperative bone remodeling for up to 1 year following surgery, which can further complicate matters [21]. The specificity of Tc-99m bone scan imaging for periprosthetic fracture increases in older prostheses once the postoperative remodeling has decreased and stabilized. CT Shoulder CT is not typically ordered for the initial evaluation of a symptomatic shoulder arthroplasty. CT with metal reduction protocol can be subsequently used to detect loosening and to further delineate a periprosthetic fracture seen on radiographs in terms of degree of displacement, extent, and comminution.