E1667. 15 Interesting Cases of Complications of Shoulder Arthroplasty Implants
  1. Akshaya Jagadale; University of Arkansas Medical School
  2. Gitanjali Bajaj; University of Arkansas Medical School
  3. Roopa Ram; University of Arkansas Medical School
  4. Kedar Jambhekar; University of Arkansas Medical School
  5. Tarun Pandey; University of Arkansas Medical School
Shoulder Arthroplasty is one of the common arthroplasty procedure and has become a mainstream treatment of end stage shoulder arthritis, benefit of preservation of joint motion and improved function, revision rates show this form of therapy is rational and promising so assessment of postoperative imaging is important. The aim of this educational exhibit is to increase the awareness about imaging findings in various shoulder arthroplasty implants and diagnose the complications early.

Educational Goals / Teaching Points
Indications for shoulder Arthroplasty. Types of shoulder Arthroplasty and various implant designs. Common and uncommon complications of Shoulder Arthroplasty and their imaging findings.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Complications of shoulder arthroplasty (Osseous, periprosthetic fracture, dislocation/subluxation, prosthetic joint infection, loosening). Soft tissue (heterotopic ossification, nerve injury). Implant specific (subsidence, osteolysis, polyethylene liner wear/displacement, component failure, malalignment, arthroplasty specific [total shoulder arthroplasty, Glenoid component loosening (38%), rotator cuff tear], reverse shoulder arthroplasty [instability 31%, scapular notching, acromion fracture], hemiarthroplasty [progressive wear of native glenoid]). Periprosthetic fracture (more common after reverse shoulder arthroplasty, intra- or postoperative [2:1], stress shielding - risk factor for periprosthetic humeral fractures, Wright and Cofield Classification). Glenoid component loosening (most common after total shoulder arthroplasty, migration, shift or tilt of glenoid component as a radiolucent line >1.5 mm thick, most commonly used radiological score is mole score). Acromion fracture (most common complication after reverse shoulder arthroplasty, common in osteoporotic patients, increase in risk of revision arthroplasty, fracture classification - depending on location of fracture line related to origin of deltoid). Scapular notching (seen with reverse shoulder arthroplasty, mechanical impingement of the humeral cup on the lateral scapular pillar during adduction, Sirveaux Classification – extent of notch in relation to inferior aspect of glenosphere). Displaced glenoid component (either dissociation of the polyethylene glenoid insert from its metal tray or dissociation of the glenosphere from its metaglene, usually requires surgical revision).

Shoulder arthroplasty has become a more commonly performed surgery due to advances in implant designs and more patient demand for maintaining active lifestyle with artificial joints. Implant designs, shapes, and coatings keep evolving to maximize their longevity in the body and promote faster recovery and better outcome. With everyday advances in arthroplasty implants, it is essential for a radiologist to become more familiar with these different varieties of implants, their combinations and possible problems they could create. Radiographs are the mainstay of shoulder arthroplasty follow-up imaging; CT, MRI, ultrasound, and nuclear medicine techniques are used if radiographs are inconclusive in case of suspicious of complications.