Intraoperative fractures in shoulder arthroplasty: risk factors and outcomes

The incidence of shoulder arthroplasty in the United States continues to increase, and while the risk of intraoperative complications such as fracture remains relatively low, there has been little investigation into whether certain patient-specific risk factors predispose to this complication. This study characterizes the incidence of intraoperative fracture during shoulder arthroplasty and additionally hypothesizes that certain risk factors may exist in addition to potentially leading to worsened near-term outcomes.

An institutional database of shoulder arthroplasties (N = 1773; 994 anatomic, 779 reverse) was retrospectively reviewed, and the operative reports for each case were examined for documentation of an intraoperative fracture, including during which surgical step the fracture took place. Various preoperative and intraoperative factors were tested for comparative significance (P < .05) using chi-square and Kruskal-Wallis tests as appropriate. Length of stay, 90-day readmission, and discharge to rehabilitation or skilled nursing facility (SNF) were further examined as secondary outcomes.

Twenty-one (1.2%) intraoperative fractures were documented, a majority of which occurred in reverse shoulder arthroplasties compared to anatomic procedures (overall incidence: 2.5% vs. 0.2%, P < .001). These most commonly occurred during either stem broaching (33%) or seating (33%) and were most likely to involve the metaphysis (53%) or greater tuberosity (33%). Five fractures occurred during revision arthroplasty, while 16 fractures occurred during primary procedures (overall incidence: 3.0 vs. 1.0%, P = .03). Patient factors reaching statistical significance included female gender and liver disease, while age and smoking history were notably not associated with intraoperative fracture. The fracture cohort had a significantly longer mean length of stay (2.42 vs. 2.17 days, P < .001). While the rates of 90-day readmission and discharge to SNF/rehab were higher in the fracture cohort, these values did not reach statistical significance.

Intraoperative fractures are a rare complication (1.2%) in shoulder arthroplasty, with reverse shoulder arthroplasty, revision cases, and female gender associated with an elevated overall risk. While these patients had a longer inpatient hospitalization, the substantially higher rates of 90-day readmission and discharge to SNF/rehab did not reach significance in our limited institutional cohort. The aforementioned incidence and risk factors serve as crucial evidence for use during the preoperative counseling process with patients as part of a shared decision-making model.