Readmission after TKA not directly correlated with index surgery

DALLAS — The causes of unplanned readmission after total knee arthroplasty varied throughout 90 days and were not directly linked with index surgery, according to study results presented here.

“What we do not understand is what percentage of readmissions can be or are directly attributable to the index procedure, and that is what we set out to discover with this study; to define the timing and the causes of unplanned readmissions to the hospital,” Robert Molloy, MD, said the American Association of Hip and Knee Surgeons Annual Meeting.

Molloy and his colleagues evaluated state inpatient databases of New York and California for total knee arthroplasties (TKAs) performed between 2005 and 2011. The frequency of causes of unplanned readmissions were identified from 0 days to 90 days after index surgery using ICD-9 diagnosis and procedure codes.

In total, Molloy and his colleagues identified 419,805 patients who underwent TKA. Of these patients, 26,924 readmissions were identified during the 90-day recovery period. Investigators noted 15,547 were identified between 0 days and 30 days; 6,593 were identified between 31 days and 60 days; and 4,784 were identified between 61 days and 90 days.

Patient readmissions were categorized as surgically or medically related. Surgically related diagnoses included infection, cellulitis, distal biceps tendons, pulmonary embolisms, component problems, periprosthetic fractures, surgical complications, pain and social modalities.

“The most common complication for readmission within the first 90 days was infection — just over 9% of readmissions were readmitted for infection. After that, we saw a decrease in infection,” he said.

In addition, all surgically related diagnoses decreased with time. Surgically related diagnoses in readmissions were 40% in the first 30 days and 16% at 61 days to 90 days. These differences were statistically significant, Molloy said.

According to Molloy, most primary diagnoses at readmission may not be directly attributed to index surgery and postoperative state up to 90 days.

“Unplanned readmissions represent a significant economic burden to the hospital systems, especially if you are in an alternative payment model and you are at risk,” Molloy said. – by Nhu Te

Reference:

Molloy R, et al. Paper #1. Presented at: American Association of Hip and Knee Surgeons Annual Meeting; Nov. 10-13, 2016; Dallas.

Disclosure: Molloy reports no relevant financial disclosures.