Poster 133: Low Socioeconomic Indicators Correlate with Critical Preoperative Glenoid Bone Loss and Care Delays
Authors: Neubauer Benjamin , Kuenze Christopher , Cherelstein Rachel , Nader Mitchell , Chang Edward 
Published: August 2024

Objectives: Increased preoperative shoulder dislocations correlate with recurrent instability and greater glenoid bone loss. Initial instability events can result in 6.8% glenoid bone loss and subsequent instability episodes can result in greater than 20% glenoid bone loss. Glenoid bone loss exceeding critical levels (>13.5%) can lead to further instability and decreased outcomes following arthroscopic labral repair. Low socioeconomic status (SES) indicators, such as high Area Deprivation Index (ADI) and non-commercial insurance, correlate with longer delays to orthopaedic care. ADI is a validated and publicly available measure ranking neighborhoods by socioeconomic disadvantage using 17 variables from the American Community Survey Five Year estimates, and recent studies have found that the combination of ADI and insurance status estimates the largest variability in the social deprivation of orthopedic patients. The goal of this study is to correlate between SES indicators, delays in care, and preoperative glenoid bone loss. We hypothesized higher national ADI and non-commercial insurance would correlate with more severe bone loss and longer delays in the treatment course of patients with anterior shoulder instability. Methods: 339 Bankart repair patients were chart reviewed for demographics, course of care, residency, and insurance status. National ADI percentile was obtained utilizing the Neighborhood Atlas Website and patients’ home addresses. Exclusion criteria included prior ipsilateral shoulder surgeries (N=16), non-viewable imaging (N=97), greater than 5 years from initial injury to surgery (N=46), and low-quality magnetic resonance imaging (N=34). Ten patients with workers’ compensation or charity insurance status were also excluded due to the low numbers in these groups. Glenoid bone loss was measured using the Best-fit circle method on high-quality MRIs (i.e. Fast imaging employing steady-state acquisition (FIEST). Researchers were blinded to SES when measuring glenoid bone loss and during inter- and intraobserver reliability testing. Interobserver reliability was .910, while intraobserver reliability was .948. Prior to evaluating the association between national ADI, time to imaging, and glenoid bone loss, a scatterplot was generated to qualitatively assess the nature of the relationship. A curve fitting tool determined that non-linear regression with a quadratic function best characterized the association between national ADI and glenoid bone loss. Treatment course and glenoid bone loss were compared between insurance types using one-way ANOVAs. Treatment course was defined as time from first instability event to MRI, first instability event to surgery, and MRI to surgery. The relationship between ADI and treatment course was assessed via Pearson’s correlation coefficients. Finally, Fisher’s exact test was used to compare critical bone loss between insurance statuses, while critical bone loss status was also compared with treatment course and ADI using one-way ANOVAs. Results: 146 patients (23.3% female; 22.4±7.0 years-old; ADI=16.1%±15.3%) were included in retrospective review. Overall, patients experienced 9.12%±6.63% glenoid bone loss and 49 patients (27.4%) had critical levels. A significant quadratic association between ADI and bone loss (R2=0.392, p<0.001) was observed. Individuals with Medicaid insurance experienced greater bone loss compared to commercial insurance (commercial=8.58%±6.69%, Medicaid=11.78%±6.30%, p=0.003). Critical bone loss was more likely with higher national ADI (p<0.001) and Medicaid insurance (OR=2.49, CI=1.02-6.09). While no difference in treatment characteristics was seen between insurance status, ADI was associated with longer times from injury to MRI (r=0.24) and injury to surgery (r=0.26). Individuals with critical bone loss experienced longer times from injury to MRI (p=0.07), but not with injury or MRI to surgery (p=0.12; p=0.79). Conclusions: Patients with low SES indicators, such as high ADI and non-commercial insurance, are associated with greater and critical levels of glenoid bone loss. Patients with higher ADI also saw delays in treatment and diagnostic imagining, with patients' delays in obtaining imaging being associated with critical bone loss. Further research on the association between SES and functional outcomes for anterior instability patients is needed.