Prosthetic overhang is the most effective way to prevent scapular conflict in a reverse total shoulder prosthesis

Methods An average and a "worst case scenario" shape in A-P view in a 2-D computer model of a scapula was created, using data from 200 "normal" scapulae, so that the position of the glenoid and humeral component could be changed as well as design features such as depth of the polyethylene insert, the size of glenosphere, the position of the center of rotation, and downward glenoid inclination. The model calculated the maximum adduction (notch angle) in the scapular plane when the cup of the humeral component was in conflict with the scapula. Results A change in humeral neck shaft inclination from 155 degrees to 145 degrees gave a 10 degrees gain in notch angle. A change in cup depth from 8 mm to 5 mm gave a gain of 12 degrees. With no inferior prosthetic overhang, a lateralization of the center of rotation from 0 mm to 5 mm gained 16 degrees. With an inferior overhang of only 1 mm, no effect of lateralizing the center of rotation was noted. Downward glenoid inclination of 0 boolean OR to 10 boolean OR gained 10 degrees. A change in glenosphere radius from 18 mm to 21 mm gained 31 degrees due to the inferior overhang created by the increase in glenosphere. A prosthetic overhang to the bone from 0 mm to 5 mm gained 39 degrees. Interpretation Of all 6 solutions tested, the prosthetic overhang created the biggest gain in notch angle and this should be considered when designing the reverse arthroplasty and defining optimal surgical technique

Current concepts in locking plate fixation of proximal humerus fractures

Despite numerous available treatment strategies, the management of complex proximal humeral fractures remains demanding. Impaired bone quality and considerable comorbidities pose special challenges in the growing aging population. Complications after operative treatment are frequent, in particular loss of reduction with varus malalignment and subsequent screw cutout. Locking plate fixation has become a standard in stabilizing these fractures, but surgical revision rates of up to 25% stagnate at high levels. Therefore, it seems of utmost importance to select the right treatment for the right patient. This article provides an overview of available classification systems, indications for operative treatment, important pathoanatomic principles, and latest surgical strategies in locking plate fixation. The importance of correct reduction of the medial cortices, the use of calcar screws, augmentation with bone cement, double-plate fixation, and auxiliary intramedullary bone graft stabilization are discussed in detail

Complications in reverse shoulder arthroplasty

The reported rate of complications of reverse shoulder arthroplasty (RSA) seems to be higher than the complication rate of anatomical total shoulder arthroplasty. The reported overall complication rate of primary RSA is approximately 15%; when RSA is used in the revision setting, the complication rate may approach 40%. The most common complications of RSA include instability, infection, notching, loosening, nerve injury, acromial and scapular spine fractures, intra-operative fractures and component disengagement. Careful attention to implant design and surgical technique, including implantation of components in the correct version and height, selection of the best glenosphere-humeral bearing match, avoidance of impingement, and adequate management of the soft tissues will hopefully translate in a decreasing number of complications in the future. Cite this article: Barco R, Savvidou OD, Sperling JW, Sanchez-Sotelo J, Cofield RH. Complications in reverse shoulder arthroplasty. EFORT Open Rev 2016;1:72-80. DOI: 10.1302/2058-5241.1.160003