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The relationship between surgeon and hospital volume and outcomes for shoulder arthroplasty.

BACKGROUND
As far as we know, no previous study has determined the relationship between volume and outcomes for shoulder arthroplasty. We hypothesized that surgeons and hospitals with higher caseloads of total shoulder arthroplasties and hemiarthroplasties have better outcomes as measured by decreased mortality rate, shorter length of stay in the hospital, reduced postoperative complications, and routine disposition of patients on discharge.


METHODS
Data on patients undergoing shoulder arthroplasty were extracted from the Nationwide Inpatient Sample databases for the years 1988 through 2000. Logistic regression with generalized estimating equations and multiple linear regression models were used to estimate the adjusted association between surgeon and hospital volume and outcomes for total shoulder arthroplasty and hemiarthroplasty after adjusting for comorbidity, age, race, household income, and sex.


RESULTS
The mortality rates for patients who had a total shoulder arthroplasty performed by surgeons who did fewer than two procedures per year (0.36%) or who did between two and fewer than four procedures per year (0.32%) were higher than those for patients who had a total shoulder arthroplasty performed by surgeons who did four procedures or more per year (0.20%). The risk-adjusted rate of postoperative complications after hemiarthroplasty was significantly higher for patients managed by surgeons who performed fewer than two procedures per year (1.68%) than for those managed by surgeons with a volume of five procedures or more per year (0.97%). The possibility of postoperative complications when total shoulder arthroplasty was performed in hospitals with a volume of fewer than five procedures (1.44%) or in those with a volume of five to ten procedures per year (1.45%) was significantly higher than that in hospitals where ten procedures or more were performed every year (0.64%). The mean lengths of stay in the hospital after total shoulder arthroplasty and hemiarthroplasty were significantly longer when the operations were performed by surgeons who did fewer than two procedures per year or when they were done in hospitals with a volume of fewer than five procedures per year or with a volume of five to fewer than ten procedures per year than when they were done in hospitals or by surgeons in the highest volume category (p < 0.001).


CONCLUSIONS
Patients who have a total shoulder arthroplasty or hemiarthroplasty performed by a high-volume surgeon or in a high-volume hospital are more likely to have a better outcome.


LEVEL OF EVIDENCE
Therapeutic study, Level III-2 (retrospective cohort study). See Instructions to Authors for a complete description of levels of evidence.