JAAOS - 2026-05-26 - Journal Article
The Effect of Technological Innovations in Reverse Total Shoulder Arthroplasty on the Rate of Periprosthetic Acromion and Scapular Spine Fractures.
Phillips T, Mousad A, Abdelshaheed JM, Beleckas C, Levy J
Topics
Key Takeaway
Across 2,380 rTSA cases over 17 years, overall acromion/scapular spine fracture incidence was 5.4%, but dropped significantly with successive technological advances, with year-to-year variability falling from 5.33% to 0.45% after routine preoperative virtual planning was adopted.
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Summary
This single-surgeon, single-implant-platform retrospective study evaluated whether successive technological innovations in rTSA—grouped into five cohorts based on implant design, surgical technique, and virtual planning milestones—were associated with reduced acromion and scapular spine fracture (ASF) incidence. Overall ASF rate was 5.4%, with rotator cuff-deficient patients carrying significantly higher risk than cuff-intact patients (7.39% vs. 2.8%, P<0.001), though this gap disappeared after 2014. A logarithmic decline in ASF incidence across the study period (r²=0.765, P<0.001) was temporally associated with technology adoption, and year-to-year variability in ASF rate dropped from 5.33% to 0.45% following routine implementation of preoperative virtual planning (P=0.008).
Key Limitation
Temporal confounding—surgeon experience accumulating over 17 years is inseparable from technology adoption—prevents causal attribution of ASF reduction to any specific implant or planning innovation.
Original Abstract
INTRODUCTION
Innovations in reverse total shoulder arthroplasty (rTSA) have improved outcomes and mitigated complications through improvements in implant design, surgical techniques, and enabling technologies. The purpose of this study was to evaluate the association between technologic evolutions in rTSA and the incidence of acromion and scapular spine fracture (ASF). The authors hypothesize that ASF incidence has decreased over time and that this decrease is temporally associated with successive changes in implant design, surgical technique, and enabling technology within a single-design platform.
METHODS
A retrospective case series from January 2007 to December 2024 was conducted. All patients undergoing rTSA by a single-implant manufacturer with a constant implant design philosophy (Enovis) were included. Patient-specific and surgical variables were collected. Five cohorts were formed based on major technologic advances focused on implant design, surgical technique, and virtual planning. Descriptive statistics were used to compare cohorts, while regression and moving average statistics assessed longitudinal trends.
RESULTS
In total, 2,380 patients met inclusion criteria, including 2,068 primary rTSA and 312 revision rTSA cases. The overall incidence of ASF was 5.4% with no notable difference between primary and revision procedures. A higher incidence of ASF was observed for patients with rotator cuff deficiency when compared with rotator cuff-intact patients (7.39% vs. 2.8%; P < 0.001). A significant decrease in ASF incidence was observed across the study period (P < 0.001), with reductions between successive technologic cohorts. Regression analysis of the data revealed a logarithmic best-fit with r2 = 0.765. Year-to-year variability in ASF incidence was significantly lower during periods of routine preoperative planning compared with earlier periods (0.45% vs. 5.33%; P = 0.008). In 2014, the difference between the rates of cuff-intact and cuff-deficient cases disappeared (P = 0.025).
CONCLUSION
Advancements in implant design and surgical technique within a single rTSA implant design philosophy were temporally associated with lower observed ASF incidence. Routine use of preoperative virtual planning coincided with the lowest ASF rates and reduced year-to-year variability. These findings should be interpreted in the context of time-related confounding, including surgeon experience and practice evolution.
LEVEL OF EVIDENCE
III.