The standard Tc-99m bone scan is a sensitive modality for the identification of abnormal bone in acute osteomyelitis, particularly in the setting of normal radiographs. However, the 3-phase bone scan is often preferred to assess for associated hyperemia in acute fracture and acute osteomyelitis. Bone scans remain low in specificity as the imaging findings can overlap with other abnormalities, such as mechanical loosening with osteolysis [30], periprosthetic fracture, and postarthroplasty bone remodeling, which can be seen up to 1 year following surgery [30]. Postoperative change and fracture healing tend to decrease over time. Fracture confirmation can also be identified with anatomic imaging (eg, radiographs, CT with metal artifact reduction techniques). Normal uncomplicated postoperative change tends to decrease over time and up to 2 years or longer after surgery [21,22], whereas aseptic loosening generally tends to progress. The specificity of bone scans for periprosthetic fracture or infection increases in older prostheses once the postoperative remodeling has stabilized. CT Shoulder CT with metal reduction protocols can elucidate the findings seen on radiographs and can further narrow the differential diagnosis in a patient suspected of periprosthetic infection as well as assist in preoperative planning [3]. CT may play a more important role after removal of the hardware and debridement in a patient with infection because it can help quantify the amount of remaining bone that can be used for revision arthroplasty [3]. CT can also be used to evaluate the surrounding soft tissues for infection and to aid in planning before image-guided joint aspiration. Administration of intravenous (IV) contrast improves the evaluation of adjacent soft-tissue fluid collections/abscesses and sinus tracts.
Imaging After Shoulder Arthroplasty PCAs. The standard Tc-99m bone scan is a sensitive modality for the identification of abnormal bone in acute osteomyelitis, particularly in the setting of normal radiographs. However, the 3-phase bone scan is often preferred to assess for associated hyperemia in acute fracture and acute osteomyelitis. Bone scans remain low in specificity as the imaging findings can overlap with other abnormalities, such as mechanical loosening with osteolysis [30], periprosthetic fracture, and postarthroplasty bone remodeling, which can be seen up to 1 year following surgery [30]. Postoperative change and fracture healing tend to decrease over time. Fracture confirmation can also be identified with anatomic imaging (eg, radiographs, CT with metal artifact reduction techniques). Normal uncomplicated postoperative change tends to decrease over time and up to 2 years or longer after surgery [21,22], whereas aseptic loosening generally tends to progress. The specificity of bone scans for periprosthetic fracture or infection increases in older prostheses once the postoperative remodeling has stabilized. CT Shoulder CT with metal reduction protocols can elucidate the findings seen on radiographs and can further narrow the differential diagnosis in a patient suspected of periprosthetic infection as well as assist in preoperative planning [3]. CT may play a more important role after removal of the hardware and debridement in a patient with infection because it can help quantify the amount of remaining bone that can be used for revision arthroplasty [3]. CT can also be used to evaluate the surrounding soft tissues for infection and to aid in planning before image-guided joint aspiration. Administration of intravenous (IV) contrast improves the evaluation of adjacent soft-tissue fluid collections/abscesses and sinus tracts.