Severe heterotopic ossification after a Rockwood type II ACJ injury in this case was successfully treated with combination of pre-operative radiotherapy, surgical excision and manipulation under anesthesia as well as NSAID therapy and physiotherapy.

Background The rate of complications after revision of reverse shoulder arthroplasty (RSA) is higher than it is in primary RSA, depending on the type of surgical intervention, the follow-up time, the preoperative condition of the patient, and the experience of the surgeon. Objective The current article represents an evaluation of the authors’ experiences with revisions of RSA and a review of literature, in order to define prognostic parameters and surgical options for the most common modes of failure. Materials and methods Between 2010 and 2019, 136 revisions of RSA were performed. Mean age of the patients at surgery was 68.3 years (29–88 years). The main indication was instability in 24 patients and chronic infection in 34. Aseptic loosening of the stem was the main indication in 15 and aseptic loosening of the baseplate in 23 patients. Periprosthetic fractures were present in 21 patients. Fractures of the scapular spine were operated on in 6 and surgery was performed for progressive notching due to malposition of the glenosphere in 4 patients. Results Staged procedures, use of allografts, and custom-made implants are common, especially for chronic infections and severe bone loss. Most of the patients (88.2%) were treated successfully. Two salvage procedures and two retentions of spacers occurred. We identified risk groups for re-revision: chronic dislocations, chronic infections, advanced bone loss, and scapular spine fractures. We observed a shift of indications and techniques, often related to the design of the implants. Conclusion These results confirm that careful preoperative planning, special implants, and a high level of experience are mandatory. With time, the authors developed an algorithm for certain indications because it was recognized that failures are often of multifactorial origin. Today, numerous implant designs which differ considerably in biomechanical features and failure modes are available. This makes revisions of RSA more complex than it was in the past.