Comparison of Short Uncemented Metaphyseal Stem and Long-Stem Reverse Shoulder Arthroplasty in Proximal Humerus Fractures: Preliminary Study at 2-Year Follow-Up

<b>Introduction</b>: In the last few years, short metaphyseal-socket prosthetic humeral stems have been introduced for reverse shoulder arthroplasty (RSA). A short stem may have advantages in humeral force distribution, reducing shear stress and preserving bone stock, keeping in mind the need for possible future revision surgery. The main objective of our study was to validate the use of a short stem prosthesis in the surgical treatment of humeral fractures by comparing clinical and radiological outcomes of our studied implant with those obtained with the use of traditional long-stem implants. <b>Methods</b>: In this multicentric, controlled prospective study, 125 patients with proximal three- or four-fragment humerus fractures were selected and treated with RSA. A short stem was used in group A (n = 53, mean age: 75.6 ± 5.6 years old), and a long stem was used in group B (n = 72, mean age: 71.76 ± 3). Active range of motion (ROM), Constant score (CS), Quick DASH, American Shoulder and Elbow Surgeons Shoulder (ASES) score, and Visual Analog Scale (VAS) scores were collected and analyzed at 2 years mean follow-up, as well as humeral and glenoid bone resorption (sum Inoue scores and Sirveaux scores were used). <b>Results</b>: No statistically significant differences were observed between group A and B in ROM, Constant score (51.69 ± 15.8 vs. 53.46 ± 15.96, <i>p</i> > 0.05), Quick DASH (31.5 ± 21.81 vs. 28.79 ± 13.72, <i>p</i> = 0.85), ASES (82.53 ± 17.79 vs. 84.34 ± 15.24, <i>p</i> = 0.57), or the VAS (0.53 ± 1 vs. 0.56 ± 1.07, <i>p</i> = 0.14) at the final follow-up. No statistically significant differences were found in the radiographic parameters between the two groups. No statistically significant differences were found for the average degree of humeral and glenoid bone resorption either. <b>Conclusions</b>: The use of a short metaphyseal-socket stem can be considered a safe, effective, and feasible option in reverse shoulder arthroplasty for treating proximal humerus fractures. Our results are encouraging, with no statistically significant differences identified between the proposed treatment and traditional long stems.