Humeral Stem Design in Reverse Total Shoulder Arthroplasty.

Purpose of the review: There have been tremendous modifications to the humeral component since Paul Grammont first introduced the reverse total shoulder arthroplasty in 1985. The purpose of this article is to review historical design features and their drawbacks and to summarize the clinical outcomes of modern designs.

Recent findings: Decreasing the neck-shaft angle and increasing humeral lateralization have helped address problems of scapular notching and limited internal and external rotation that were common with traditional designs. Advancements in proximal porous coatings have also facilitated the development of short-stem and stemless implants, which decreases the need for cement fixation and allows preservation of bone stock. Moreover, a reduction in stem length with smaller metaphyseal and diaphyseal filling ratios may limit stress shielding. Current humeral implants have an aseptic loosening rate less than 1%. Despite promising results, many of these new humeral design features do not have long-term data and continued surveillance of their performance is necessary. The humeral stem design significantly influences clinical and radiographic outcomes. Surgeons should be mindful of these design variables to increase impingement-free range of motion, minimize scapular notching, reduce stress shielding, and improve implant survivorship.