American Academy of Orthopaedic Surgeons Annual Meeting
American Academy of Orthopaedic Surgeons Annual Meeting
March 13, 2014
1 min read

Study: Added comorbidities increases in length of stay, costs after TKA

You've successfully added to your alerts. You will receive an email when new content is published.

Click Here to Manage Email Alerts

We were unable to process your request. Please try again later. If you continue to have this issue please contact

NEW ORLEANS — Research presented here links additional patient comorbidities to increases in hospital length of stay and charges for total knee arthroplasty.

“We have used the 2009 [National Inpatient Sample] NIS database to evaluate primary total knee arthroplasty (TKA) and found the average hospital costs were $14,500, mean charges were $49,000 and the mean hospital stay was 3.3 days. Both costs and length of stay rise dramatically with increases in patient comorbidity,” Andrew J. Pugely, MD, said at the American Academy of Orthopaedic Surgeons Annual Meeting.

He added, “The current reimbursement schemes may not adequately account for these multiple comorbidity patients, and as payments continue to decline, it is imperative that policymakers look to provide fair adjustments to reimbursements after total knee arthroplasty. Otherwise, we fear restrictions in access to care may occur.”

Using ICD-9 codes, the researchers identified 621,000 patients who underwent primary TKA in 2009. Pugely noted information in the database allows for conversion of hospital charges to hospital costs. After obtaining costs, the investigators used linear models to calculate the effect of patient characteristics on costs and length of stay.

They found 12% of patients had no comorbidities, while a third of patients had three or more comorbidities. The most common were hypertension, diabetes and obesity.

“Baseline costs were about $14,500, but patients with zero comorbidities cost less at $13,700 and those with seven or more comorbidities were $5,000 more with $17, 700,” Pugely said. “With each successive comorbidity, there was a statistically significant increase in cost. The same trend was true for hospital length of stay.”

He noted patients without comorbidities had a length of stay of 2.9 days, while patients with 7 comorbidities or more stayed nearly 2 days longer. — by Gina Brockenbrough


Pugely AJ. Paper #405. Presented at: the American Academy of Orthopaedic Surgeons Annual Meeting; March 11-15, 2014; New Orleans. 

Disclosure: Pugely has no relevant financial disclosures.