The addition of SPECT or SPECT/CT improves anatomic localization of new bone formation [20] but remains nonspecific. A positive 3-phase bone scan can be seen in periprosthetic infection, periprosthetic fracture, and in the early postoperative state. 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 increases in older prostheses once the postoperative remodeling has stabilized. Image-Guided Aspiration Shoulder Aspiration of the shoulder should be performed when there is suspicion for an infected shoulder arthroplasty clinically, with or without radiographic evidence of infection, to avoid the destructive soft-tissue and bone changes that can result from an untreated infection. Imaging-guided aspiration procedures provide a minimally invasive means to sample fluid from the joint suspected of infection [34,35]. Shoulder joint aspiration has been shown to have a sensitivity of 33% and specificity of 98% [36]. Shoulder aspiration can be completed with the use of fluoroscopy, US, and CT guidance. MR guidance is possible but rarely utilized. Arthrography can be performed along with aspiration, when done under fluoroscopy and CT, to confirm the intra-articular origin of any aspirated fluid as well as to assess for any extension of the infectious process into adjacent bursae, sinus tracts, and abscesses [34]. Bone Scan Shoulder The use of nuclear imaging for the evaluation of periprosthetic infection has been limited to the evaluation of hip and knee arthroplasties, but various clinical studies anecdotally suggest utilizing this modality in shoulder arthroplasties [30].
Imaging After Shoulder Arthroplasty PCAs. The addition of SPECT or SPECT/CT improves anatomic localization of new bone formation [20] but remains nonspecific. A positive 3-phase bone scan can be seen in periprosthetic infection, periprosthetic fracture, and in the early postoperative state. 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 increases in older prostheses once the postoperative remodeling has stabilized. Image-Guided Aspiration Shoulder Aspiration of the shoulder should be performed when there is suspicion for an infected shoulder arthroplasty clinically, with or without radiographic evidence of infection, to avoid the destructive soft-tissue and bone changes that can result from an untreated infection. Imaging-guided aspiration procedures provide a minimally invasive means to sample fluid from the joint suspected of infection [34,35]. Shoulder joint aspiration has been shown to have a sensitivity of 33% and specificity of 98% [36]. Shoulder aspiration can be completed with the use of fluoroscopy, US, and CT guidance. MR guidance is possible but rarely utilized. Arthrography can be performed along with aspiration, when done under fluoroscopy and CT, to confirm the intra-articular origin of any aspirated fluid as well as to assess for any extension of the infectious process into adjacent bursae, sinus tracts, and abscesses [34]. Bone Scan Shoulder The use of nuclear imaging for the evaluation of periprosthetic infection has been limited to the evaluation of hip and knee arthroplasties, but various clinical studies anecdotally suggest utilizing this modality in shoulder arthroplasties [30].