Background: The annual volume of major cardiovascular and oncologic
procedures performed in hospitals and by surgeons has been inversely
associated with the rates of perioperative mortality and complications. The
relationship between hospital and surgeon volume and perioperative outcomes
following total knee replacement has received little study.
Methods: We analyzed claims data for Medicare patients who had
elective primary total knee replacement between January 1 and August 31, 2000.
Hospital and surgeon volumes were defined as the number of primary and
revision total knee replacements performed in the hospital or by the surgeon
in Medicare recipients in 2000. We examined the associations between the
annual volumes of total knee replacement performed in the hospitals and by the
surgeons and the rates of mortality and complications (infection, pulmonary
embolus, myocardial infarction, or pneumonia) in the first ninety days
postoperatively. The analyses were adjusted for age, gender, comorbid
conditions, Medicaid eligibility (a marker of low income), and arthritis
diagnosis. Analyses of hospital volume were adjusted for surgeon volume and
Results: Twenty-five percent of the primary total knee replacements
were done by surgeons who performed twelve of these procedures or fewer in the
Medicare population annually, and 11% were done in hospitals with an annual
volume of twenty-five of these procedures or fewer. Compared with the patients
who had a primary total knee replacement in hospitals with an annual volume of
twenty-five procedures or fewer, those managed in hospitals with an annual
volume exceeding 200 procedures had a lower risk of pneumonia (odds ratio,
0.65; 99% confidence interval, 0.47 to 0.90) and any of the adverse outcomes
examined (death, pneumonia, pulmonary embolus, acute myocardial infarction, or
deep infection) (odds ratio, 0.74; 99% confidence interval, 0.60 to 0.90).
Similarly, patients who had a primary total knee replacement done by surgeons
who performed more than fifty such procedures in Medicare recipients annually
had a lower risk of pneumonia (odds ratio, 0.72; 99% confidence interval, 0.54
to 0.95) and any adverse outcome (odds ratio, 0.81; 99% confidence interval,
0.68 to 0.98) compared with patients of surgeons with an annual volume of
twelve procedures or fewer.
Conclusions: Patients managed at hospitals and by surgeons with
greater volumes of total knee replacement have lower risks of perioperative
adverse events following primary total knee replacement. Patients and
clinicians should incorporate these findings into discussions about selecting
a surgeon and a hospital for total knee replacement. These data should also be
integrated into the policy debate about the advantages and drawbacks of
regionalizing total joint replacement to high-volume centers.
Level of Evidence: Prognostic study, Level II-1
(retrospective study). See Instructions to Authors for a complete description
of levels of evidence.