Hospital Network Centralization of Primary Total Joint Arthroplasty Is Associated With Reduced Early Complication Rates But Not Reduced Readmission or Reoperation Rates: A Retrospective Database Study.

Background: Hospital networks centralize primary total joint arthroplasty (TJA) within their existing systems to develop specialized service lines with higher surgical volumes to reduce adverse events. It is not known what role hospital network centralization has had on primary TJA outcomes.

Purpose: We sought to determine whether the degree of hospital network centralization for primary TJA is associated with (1) 90-day postoperative complication rates, (2) 90-day hospital readmission rates, or (3) 1-year revision rates.

Methods: We conducted a retrospective database study of Medicare Part A beneficiaries who underwent inpatient primary TJA for osteoarthritis in 2016 and 2017 (n = 523,142 patients); individual hospital-level characteristics and hospital networks were also identified (n = 360 unique networks, n = 3339 hospitals). Patients having surgery at a hospital that was not a member of a health care network were excluded (n = 163,998 patients) because we wanted to examine only the role of network structures on outcomes; this resulted in a cohort of 359,144 patients. Hospital network centralization, which was defined as the percentage of total network cases performed at the highest volume hospital and categorized into quartiles (eg, lowest 25% of networks by concentration, 26%-50% of networks by concentration, etc). Primary outcomes included postoperative 90-day complications, 90-day readmissions, and 1-year revisions. Multivariable logistic and linear regressions evaluated associations of hospital network centralization with outcomes and controlled for relevant patient-level and hospital-level covariates, including hospital network volumes.

Results: Odds of 90-day complications were lower in the most centralized hospital networks than in least centralized networks (odds ratio [OR] = 0.85; 95% confidence interval [CI]: 0.75, 0.95). Degree of centralization was not associated with readmissions or 1-year revision rates. Non-modifiable patient and individual hospital characteristics appeared to have a greater association with complications, readmissions, and early revision rates than hospital network centralization or volume.

Conclusion: This retrospective database study found that increased centralization of primary TJA within a hospital network was associated with lower 90-day complication rates but not with 90-day readmission or 1-year revision rates. This suggests that structural changes within hospital networks may be beneficial to reduce early complications in this patient population. In addition, our findings suggest that risk adjustment in assessing non-modifiable patient and hospital risk factors may be important when assessing TJA outcomes.