Introduction: In most of the reported series, scapular notching in inverse shoulder arthroplasty has been identified as a major problem. Therefore, a novel concept has been developed in order to minimize the incidence and the evolution (pathophysiology) of scapular notching. The current cohort study is now large enough to examine the results with special attention on notching.

Methods: A dual peg design of the metaglene with CaP coating provides high primary and secondary stability. “Geometrical” notching is reduced by inferior (eccentric) fixation of the glenosphere on the metaglene, beveling of the medial part of the humeral inlay, and by the choice of three different sizes of the glenosphere (36, 39 and 42). “Biological” notching is addressed by inversion of the components: the epiphysis – as the mobile part – is metallic. Its contact to the scapula, should this occur, cannot lead to polyethylene wear. This study is a prospective multicentric study on Affinis Inverse and Affinis Fracture Inverse shoulder prosthesis (Mathys Ltd Bettlach, Switzerland), which is running in 7 European hospitals since December 2007. All cases but two (lost to follow-up) are included.

Preoperative and all postoperative radiographs were reviewed. Notching has been graded 0 to 4, on a scale adapted after Sirveaux.

Results: At submission deadline for the abstract, 163 cases were included. Grade 1 notching was detected in 8 cases (4.9%), and grade 2 notching in one. In those cases, notching developed early, but was not progressive over time. There were no cases of grade 3 or 4. In 17 cases, the X-rays were not assessable and therefore it was impossible to definitively rule out a possible grade 1 notching. None of the Affinis Fracture Inverse prostheses produced any notching. New bone apposition on the inferior aspect of the scapula was detected in 15 cases. We postulate this to be a metaplasia of the long head of the triceps due to local periosteal stimulation.

Conclusions: The present design leads to a very low rate of scapular notching. Even in the 9 cases where notching was present, it appears that the epiphysis only created the space it needed, without any ongoing osteolytic process beyond this. Specific prosthetic design improves both quantity and quality of scapular notching.

This prospective follow-up study investigates the correlation between healing of the tuberosities and the functional outcome after arthroplasty with a trauma shoulder prosthesis in elderly patients with non-reconstructable humeral head fractures.

Surgery was performed on 65 patients (66 cases). Patients underwent clinical and radiological evaluation.

A total of 56 patients (57 cases) were examined after a mean time to follow-up of 16 months (range 4–62 months). Mean Constant Score was 50 and the age- and gender-corrected value was 73%.

The Constant Score was significantly higher (62 points, p=0.015) if the tuberosities healed. Mean ASES index was 68 and correlated significantly to the Constant Score (r=0.77).

Healing of the tuberosities is crucial to achieve good functionality in patients treated with a humeral head prosthesis. For elderly patients, the main objectives are to recover the ability to perform activities of daily living, to become pain free, and to reach a high level of satisfaction. All these criteria are largely achieved by the procedure described in this paper.