Stemless shoulder arthroplasty-current results and designs

Stemless shoulder arthroplasty was originally introduced in 2004 by a single manufacturer. Now, over a decade later, numerous designs are available outside the USA, but as yet, only one implant has been cleared by the Food and Drug Administration (FDA) and is available for use within the USA. Often referred to as "canal sparing," these implants are designed for metaphyseal fixation to minimize humeral bone removal, avoid intraoperative and postoperative humeral fracture complications, and to decrease morbidity associated with revision operations. Recently, the second generation of stemless arthroplasty, a convertible implant allowing use in either anatomic or reverse arthroplasty configuration, was released for use outside the USA. This paper will review the available designs, reported results, and raise potential concerns for this emerging technology.