The study authors sought to determine whether or not blood sugar level (glycemic control) influenced outcome in TKR. Fifty-two percent of people with diabetes have arthritis. Previous studies have found that poor glycemic control may cause postoperative complications.

Researchers reviewed records of more than 40,000 Kaiser Permanente patients who underwent TKR between January 2001 and December 2009, of whom 7,567 (18.7 percent) had diabetes, 464 underwent revision surgery (1.1 percent), and 287 (.7 percent) developed a deep infection. Of the total number of patients, 12.5 percent had controlled diabetes and 6.2 percent had uncontrolled diabetes.

In this study, researchers found no significant increase in risk for TKR revision, deep infection or deep vein thrombosis in patients with diabetes -- controlled or uncontrolled -- compared to patients without diabetes.

Other Key Findings:

• Patients with diabetes were more likely than patients without diabetes to be obese (56.7 percent compared with 40.3 percent), and have a severe comorbidity (related disease/condition) burden (17.5 percent compared with 2.4 percent).
• The rates of deep infection, deep vein thrombosis and pulmonary embolism (when a blood clot reaches the lungs) were low, and comparable in the controlled and uncontrolled diabetic groups to the non-diabetic group.
• Uncontrolled diabetics did not appear to be associated with an increased risk of myocardial infarction (heart attack) or rehospitalization.
• Controlled diabetics had a slightly greater percentage of revisions (1.7 percent) compared to uncontrolled diabetics (1.2 percent).

"This current study suggests that patients with diabetes who have higher glucose levels may not be at greater risk of poor surgical outcomes," said Annette L. Adams, PhD, MPH, of the Kaiser Permanente Southern California Department of Research & Evaluation. "There appear to be other factors at play, and patients and their providers need to consider multiple factors, including but not limited to diabetes status, as they make decisions about whether to have this surgery."