Infection is Leading Cause of Failed Prosthetic Knee Joints

The number of revision total knee replacement surgeries continues to increase with periprosthetic joint infection and mechanical loosening found to be the most common reasons for revision, according to recent study data.

“Despite the success of primary total knee arthroplasty (TKA) in reducing pain and improving function in patients who suffer from knee osteoarthritis, the number of revision TKA procedures performed annually in the United States continues to rise,” Kevin J. Bozic, M.D., MBA, William R. Murry, M.D., Endowed Chair in Orthopaedic Surgery, professor and vice chair at the University of California, San Francisco, said. “Understanding the cause of TKA failure, the types of revision TKA procedures being performed, and the resource utilization associated with these procedures is essential to improving TKA outcomes.”

Researchers used a Nationwide Inpatient Sample to evaluate the cause of failure for 301,718 revision TKA procedures performed between 2005 and 2010 and compared patient characteristics, procedure information and resource utilization across revision TKA procedures.

They found that the number of revision TKA procedures increased from 48,260 in 2006 to 67,534 in 2010. Revision TKA procedures were more common in women and most commonly performed in patients between the ages of 65 years to 74 years.

The researchers recorded a moderate severity of illness score in more than 60 percent of patients studied. Periprosthetic joint infection and mechanical loosening were the most common reasons for revision, accounting for revision in 25 percent and 18 percent of patients, respectively. Among the revisions in 2010, 37 percent were due to all-component revisions, 13 percent to arthrotomy/removal of prosthesis, 12 percent to isolated tibial insert revision, 10 percent to tibial component revision, 5 percent to patellar component revisions and 4 percent to femoral component revisions. Osteolysis and periprosthetic fracture were least common reasons for revision.

Revision TKA procedures were more common in large, urban non-teaching hospitals and in the South and Midwest regions. Longest length of stay was associated with periprosthetic joint infection and periprosthetic fracture and periprosthetic fracture was associated with the highest average hospitalization costs, according to study results.