Since its introduction 25 years ago reverse arthroplasty has evolved into an indispensable technique in the field of shoulder surgery. Today probably more than 50% of shoulder arthroplasties are performed as a reverse prosthesis. This technique not only provides a very effective treatment of cuff tear arthropathy, but also in many cases, is the only solution for problems in revision arthroplasty of the shoulder.

Despite of the significant advantages, some major concerns of this technique are still unsolved, one of which is inferior scapular notching. The erosion of bone in the inferior part of the glenoid, which potentially leads to loosening and failure of the glenosphere component is a result of 2 mechanisms:

1. mechanical impingement of the humeral component to the inferior scapular neck in adduction
2. Polyethylene (PE) wear of the reverse liner material, inducing biological osteolysis of the scapula next to the mechanically caused notching defect. 

LIMA, with the SMR shoulder arthroplasty system, have developed a group of implants which provide unique modularity both at the humeral as well as glenoid side. With the introduction of the 40 and 44 mm PE-glenospheres some more features have recently been added to the system. The use of these larger glenospheres potentially provide greater stability and larger range of motion compared to the standard smaller 36 mm glenospheres. Moreover due to major changes in design and material these implants have a high potential to effectively counteract the problem of scapular notching. 

The asymmetric shape of the glenosphere component provides an overhang of the implant across the inferior part of the glenoid,

thus reducing the risk of mechanical impingement of the humeral component against the scapula. Inversion of materials: the glenosphere is manufactured from PE, the humeral reverse liner from metal, thus potentially minimizing the risk of PE wear and

subsequent osteolysis of the scapular bone. Using the SMR system since 2006

in primary as well as revision shoulder arthoplasty, I now have implanted the new40and44mm glenospheres in more than 50 cases without a complication and with excellent clinical and radiological results. Due to the fact that significant concerns about the longevity of reverse shoulder prostheses have found new and promising answers in the design of the SMR components, their use has now become my standard technique in reverse arthroplasty.