[Shoulder prosthesis replacement options : New implants, treatment algorithms and clinical results].

BACKGROUND: Bony defect situations are a common problem in revision arthroplasty of the shoulder and are the cause of the complexity of the procedure. Aseptic and septic loosening as well as difficult implant removal can result in humeral and/or glenoid bone loss. PLANNING: A careful preoperative imaging is needed to estimate the extent of the bony defect and to enable precise planning of the bone reconstruction and the required implants. However, the size of the defect needs to be re-evaluated intraoperatively after removal of the implant components and any larger defects have to be addressed appropriately. PROSTHESIS
DESIGN: While in the glenoid autologous bone grafts and, to a lesser extent, allogenic bone grafts are preferred, metallic augmented implants have recently become available to fill the glenoid bone defect. However, humeral defects are normally addressed with longer revision stems, possibly with allograft augmentation. The soft tissue loss in proximal humeral defects can be addressed with fixation techniques to improve function and reduce the risk of dislocation. Modern modular prosthesis designs allow prosthesis conversion while leaving bony, tightly integrated component parts on the glenoid or shaft. This review describes the preoperative diagnostic steps as well as techniques for revision surgery of the shoulder in the case of bone loss.