Optimisation of reverse total shoulder arthroplasty through the combination of prosthesis placement modifications

Modifying the placement of the reverse total shoulder arthroplasty (RTSA) prosthesis can have an effect on functional outcomes. A biomechanical model of the shoulder was used to evaluate 48 RTSA configurations. To determine which of these was an optimised configuration, a total of 5040 simulations were performed and four outcome measures were assessed during each simulation. It was determined that the simultaneous implementation of 5 mm inferior glenosphere translation and 5 mm posteromedial humeral tray translation maximised functional outcomes (i.e. impingement-free range of motion, joint stability, and deltoid moment arms).