Pre-Op Hip, Knee Injections May Up Infection Risk

At the 2016 Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS), data from 2 studies indicated injections received in the months prior to total knee or total hip replacement surgery may increase the risk for infection and related complications.

Most hip and knee injections used to relieve pain and inflammation in osteoarthritis contain corticosteroids. While they act in suppressing pain and inflammation, they also suppress the immune system. This increases the patient’s risk for severe, post-operative infections that may lead to additional surgery, prolonged antibiotic use, and possibly death.

The first study, “Preoperative Hip Injections Increase the Rate of Periprosthetic Infection After Total Hip Arthroplasty,” looked at data from patients in the Statewide Ambulatory Surgery and Inpatient Database (n=177,762) for Florida and California from 2005-2012. Injections given within 3 months of total hip replacement surgery was associated with a 40% increased risk for post-op infection. Rate of infection after 1 year was 2.06% in patients who did not receive an injection vs. 2.81% in patients who received an injection within 3 months before their procedure. Injections seemed safe when administered more than 3 months pre-operatively (0.87% rate).

The second study, “Do Injections Increase the Risk of Infection Following Total Knee Arthroplasty,” evaluated patients in the Humana database (n=83,684) who had total knee replacement for the first time between 2007-2014. Patients with an injection prior to total knee replacement had a significantly higher rate of surgical site infection than those without (4.4% vs. 3.6%), as were the rates of infection requiring a return to the operating room (1.5% vs. 1%). Specifically, patients who had an injection within 1 month of surgery had a higher rate of infection requiring a return to the operating room vs. patients who had an injection 7 months prior to surgery (odds ratio [OR] 1.8 vs. 1.4).

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