1 Introduction

The obesity epidemic continues to drive a dramatic rise in metabolic disease burden across the United States, with substantial implications for orthopedic surgery. Obesity-related comorbidities, including type 2 diabetes, hypertension, and dyslipidemia, are known contributors to osteoarthritis and musculoskeletal degeneration, increasing demand for surgical intervention such as joint arthroplasty and soft tissue repair. ^1–3 Among these comorbidities, non-alcoholic fatty liver disease (NAFLD) has emerged as the most prevalent chronic liver condition globally, now estimated to affect over 25 % of adults worldwide and up to 40 % in some U.S. populations. ^4–6 NAFLD represents a spectrum of liver disease ranging from simple steatosis to non-alcoholic steatohepatitis (NASH), which may progress to fibrosis, cirrhosis, and hepatocellular carcinoma. ⁷

Although the impact of advanced liver disease on surgical risk has been well documented, the orthopedic relevance of early-stage NAFLD is often underrecognized. ^8–10 NAFLD has been independently associated with increased perioperative complications across general surgery and cardiac surgery cohorts, ^11,12 yet relatively few studies have examined its effect in orthopedic populations. ^13,14 This knowledge gap is especially relevant in shoulder surgery, where increasing procedural volumes for rotator cuff repair (RCR) are observed in aging, overweight populations. ^15,16 As the prevalence of NAFLD tracks closely with obesity and osteoarthritis, many patients presenting for RCR may harbor hepatic dysfunction that is not always clinically apparent. ^17,18

Prior work has shown cirrhosis to confer elevated risks of surgical site infection, bleeding, readmission, and mortality in orthopedic patients. ^8,19–21 However, the comparative postoperative risk profiles of NAFLD versus non-alcoholic cirrhosis remain poorly defined in this domain. Direct comparisons between these distinct but related hepatopathies are essential for improving risk stratification and tailoring perioperative care. In particular, understanding whether early-stage hepatic dysfunction (i.e., NAFLD) imparts similar postoperative vulnerability as cirrhosis may influence both surgical decision-making and resource allocation.

The purpose of this study was to evaluate 90-day postoperative complications following rotator cuff repair in patients with NAFLD versus those with non-alcoholic cirrhosis, using a large national administrative claims dataset. We hypothesized that patients with cirrhosis would experience higher complication rates than those with NAFLD, even after adjusting for baseline comorbidities.

2 METHODS

3 Results

4 Discussion

In this matched cohort study of 1384 patients undergoing rotator cuff repair, we found that individuals with NAFLD experienced significantly lower rates of 90-day postoperative complications and hospital readmissions compared to those with non-alcoholic cirrhosis. These findings support the hypothesis that severity of hepatic dysfunction remains a key determinant of surgical risk, even when controlling for age, sex, and comorbid disease burden. Notably, these differences persisted despite a higher baseline prevalence of obesity, osteoarthritis, COPD, and tobacco use in the NAFLD cohort, suggesting that cirrhosis itself remains a dominant driver of adverse postoperative events.

Our findings align with prior studies demonstrating elevated surgical risk in cirrhosis, including increased rates of infection, hemorrhage, renal dysfunction, and mortality across orthopedic and general surgical procedures. ^8,19–22 The mechanisms underlying these risks likely involve impaired coagulation, diminished immune function, altered drug metabolism, and systemic inflammation associated with hepatic decompensation. ^13,23,24 In contrast, while NAFLD reflects earlier-stage hepatic injury, it may carry less overt physiologic compromise, particularly in the absence of significant fibrosis or portal hypertension. ^25,26

Importantly, the orthopedic implications of NAFLD are increasingly relevant in the context of rising metabolic disease. With over 40 % of U.S. adults classified as obese and the incidence of NAFLD projected to increase by 21 % by 2030, a growing proportion of surgical candidates will fall somewhere along the NAFLD spectrum. ^6,27 NAFLD has been associated with higher rates of osteoarthritis, possibly through shared inflammatory and metabolic pathways. ^3,28 Thus, patients presenting for rotator cuff repair or joint arthroplasty may be at increased surgical risk not only due to mechanical factors related to obesity but also metabolic dysfunction underlying NAFLD.

This study provides valuable insight into how early-stage liver disease compares to more advanced hepatic pathology in influencing surgical outcomes. Our results suggest that while NAFLD may not independently confer substantially elevated orthopedic risk compared to cirrhosis, it should not be viewed as entirely benign. In fact, NAFLD patients exhibited several adverse baseline features, such as higher rates of obesity, tobacco use, and osteoarthritis, that may synergize with hepatic dysfunction to shape outcomes. Further studies with histologic or elastographic staging could clarify whether fibrosis burden within NAFLD patients further modulates surgical risk.

5 Limitations

This study has several limitations inherent to its retrospective design and reliance on administrative claims data. First, the identification of liver disease status and postoperative complications was based on ICD and CPT coding, which is subject to potential misclassification. Although we used previously validated codes to define both non-alcoholic fatty liver disease and non-alcoholic cirrhosis, inaccuracies in diagnostic coding may lead to erroneous cohort allocation. Notably, NAFLD remains frequently underdiagnosed in clinical practice, which could result in an underrepresentation or mislabeling of affected patients within the database.

While propensity score matching was employed to minimize baseline differences, residual confounding due to unmeasured variables cannot be excluded. Factors such as nutritional status, frailty, sarcopenia, alcohol history below coding thresholds, medication use, and socioeconomic context are not captured in claims-based datasets and may influence postoperative risk. Furthermore, the inability to stratify NAFLD patients by fibrosis stage limits our understanding of how disease severity within the NAFLD spectrum may differentially affect surgical outcomes. As the database lacks clinical and laboratory parameters such as liver enzyme levels, MELD or Child-Pugh scores, and imaging or biopsy findings, our ability to assess hepatic function and reserve was limited.

The PearlDiver Mariner database also does not provide granular perioperative data such as surgical technique, tear size, fixation method, anesthesia type, or postoperative rehabilitation protocols, all of which may impact outcomes following rotator cuff repair. Additionally, because the dataset primarily includes patients with private insurance and Medicare Advantage plans, the generalizability of our findings to uninsured or underinsured populations remains uncertain.

Finally, this study focused on short-term outcomes within 90 days of surgery. Long-term functional recovery, retear rates, patient-reported outcomes, and progression of hepatic disease beyond the studied time window remain important areas for future investigation, particularly in light of the chronic and progressive nature of both NAFLD and cirrhosis.

6 Conclusion

In patients undergoing rotator cuff repair, the presence of NAFLD was associated with a reduced risk of postoperative complications and readmission compared to non-alcoholic cirrhosis. These findings underscore the importance of liver disease severity in orthopedic risk stratification and perioperative planning.

Guardian patient consent

Guardian/Patient consent was not needed for this study.

Credit author statement

Catherine Hand: Writing – review and editing, Methodology, Conceptualization. Jared Sasaki: Writing – review and editing, Conceptualization. Camden Bohn: Writing – review and editing. Francis Hand: Software, Validation. Kyleen Jan: Writing – review and editing. Daniel Shinn: Writing – review and editing, Supervision. Brian Forsythe: Supervision, Project Administration.

Ethical statement

Institutional Ethical Committee Approval was not needed for this study. However, we upheld publishing ethics as our duty as authors.

Funding statement

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.