Total shoulder arthroplasty: are the humeral components getting shorter?

Abstract

Each generation of total shoulder arthroplasy has improved on the previous. The newest humeral component innovation is shortening the humeral component or eliminating the stem entirely to rely on stemless fixation in the humeral metaphysis. This offers theoretical advantages of preserved bone stock, less stress shielding, eliminating the diaphyseal stress riser, ease of stem removal at revision, and humeral head placement independent from the humeral shaft axis. There are a number of short term cohorts that have shown low complication rates and outcomes similar to previous generations of stemmed humeral components. Longer term and better designed studies are needed in order for short stems and stemless components to become the standard of care.

Short-stem anatomical shoulder replacement—a systematic review

“…This may result in massive bone loss, which requires complex revision surgery. The rationale of implants with metaphyseal fixation that are either stemless or have a short humeral stem is the facilitation of stem removal and preservation of bone in the event of revision surgery [11]. One other important aspect is the occurrence of stress shielding in longstem humeral components, which is associated with aseptic loosening and bone loss in the longer term [16].…”

“…In an effort to mimic native bone stress and to preserve bone in the case of revision surgery, design modifications led to the fourth generation of shoulder arthroplasty with stemless or short-stem humeral components aimed at metaphyseal fixation [7,11,14]. In 2016, Harmer et al performed a systematic review of stemless and short-stem shoulder prosthesis and found that only one study reported results of anatomical shoulder replacement with an uncemented short stem [11]. The authors therefore concluded that longer-term and betterdesigned studies are needed if short stems and stemless components are to become the gold standard for care.…”

“…In 2016, Harmer et al wrote a review of new humeral components in shoulder arthroplasty and considered whether "humeral components are getting shorter?" [11]. At that time, only one study by Jost et al about the results of anatomic short-stem prostheses had been published [13].…”

Restoration of the joint geometry and outcome after stemless TESS shoulder arthroplasty

“…In recent review articles, the overall complication rate lies between 4.2% and 15.2%[ 14 , 15 ]. In the literature, an arthrofibrosis after shoulder arthroplasty is rarely documented[ 15 , 16 ], whereas a rotator cuff failure is reported with incidences between 1.3% and 14%[ 17 - 19 ] and a plexus lesion with incidences up to 15%[ 20 , 21 ]. Taken together, our complication rate is high and lies in the upper range compared to the literature.…”

Comparison of revision rates and radiographic observations of long and short, uncoated and coated humeral stem designs in total shoulder arthroplasty

“…Humeral stems have gone through many design adaptations, from first-generation cemented Neer stems with a unique geometry in five sizes of increasing diameters, to fourth-generation uncemented humeral stems, featuring short and stemless designs. 28 Cemented long stems, which were the norm from the late 1970s to the early 2000s, largely improved in function and pain, 4,29 but their revision rate is around 10% at ten years and 20% to 30% at 20 years. 7,30 Our review revealed overall stem revision rates of 9% to 14% at 10 to 20 years for uncemented uncoated long designs.…”