
There is great interest in stemless implants for shoulder arthroplasty.
Some articles, such as the recent Radiographic comparison of eccentric stemmed versus concentric stemless prosthetic humeral head positioning after anatomic total shoulder arthroplasty focus on the degree to which the arthroplasty created the desired head position and concluded that “stemless and stemmed aTSA implants have similar rates of reproducing satisfactory postoperative humeral head center of rotation.”
Both types of humeral replacements are subject to the surgeon’s ability to “get it right”. Below is an example of overstuffing a stemless part due to an incorrect humeral cut.
Another recent article Impact of Humeral Stem Length on Calcar Resorption in Anatomic Total Shoulder Arthroplasty pointed out that while resorption of calcar bone occurred with stemless, short stemmed and standard stemmed implants, higher degrees of resorption were less common with the stemless design because it directly loads the calar.

Contrary to designs in which the calcar is unloaded and loaded onto the metaphysis

These authors did not find any clinical significance in these differences.
