[Shoulder Arthroplasty]

Shoulder arthroplasty has been performed increasingly during the last years. The concept of modern anatomic shoulder arthroplasty is based on C. S. Neer's first shoulder prosthesis in the 1950s which was originally designed for the treatment of fractures of the proximal humerus. Since then, this monoblock prosthesis has undergone many changes and improvements. By now, an anatomic reconstruction of the joint is possible. Hence, the indications for anatomic shoulder arthroplasty have been added amongst others by osteoarthritis, necrosis, rheumatoid arthritis or posttraumatic arthritis. For years stemmed shoulder arthroplasty has been state of the art with a good clinical and radiological outcome. Nevertheless, stem-related problems occurred leading to the invention of short-stem and stem-free shoulder prosthesis. Stem-free shoulder arthroplasty allows an even better anatomic reconstruction and therefore offers more opportunities, e.g. in a severe posttraumatic status. Only short- to midterm results are published so far but those are very convincing indicating that stem-free shoulder arthroplasty is the future. Reverse shoulder arthroplasty has its origin in the 1980s. Paul Grammont invented a reversed shoulder prosthesis for patients suffering from cuff arthropathy. The center of rotation is medialised and inferiorised using the pre-loading of the deltoid muscle to move the shoulder joint. The initial prosthesis had undergone many variations as well but in contrast to anatomic shoulder arthroplasty biomechanics is still discussed a lot in reverse shoulder arthroplasty; especially in terms of finding the right inclination angle or how to prevent instability or scapular notching. This article gives a review about indications, concepts and complications of shoulder arthroplasty.