Sat., 10/6/12 General Interest, PAPER #99, 1:38 pm OTA-2012
Risk of Obtaining Routine Cultures During Presumed Aseptic Orthopaedic Procedures
Matthew A. Napierala, MD; Jaime L. Bellamy, DO; Clinton K. Murray, MD;
Joseph C. Wenke, PhD; Joseph R. Hsu, MD; Skeletal Trauma Research Consortium (STReC);
San Antonio Military Medical Center, Fort Sam Houston, Texas, USA
Background/Purpose: Infection has been well established as a contributing factor to nonunion, as well as the need for other secondary procedures. For this reason, many surgeons perform intraoperative cultures routinely even when there is no suspicion of infection. The results of these routine cultures may lead to antibiotic treatment and the risk of subsequent antibiotic complications without reducing the rate of infection. To our knowledge, there are no studies evaluating the morbidity involved with obtaining routine intraoperative cultures. We hypothesize that the use of routine cultures leads to an increased rate of adverse effects without a decreased rate of deep infection.
Methods: All patients who underwent bone grafting for presumed aseptic nonunions, presumed aseptic heterotopic ossification excision, presumed aseptic symptomatic hardware removal, and presumed aseptic amputation revision at our institution between March 2005 and June 2008 were identified using surgical and inpatient databases. Within this cohort, four groups were identified. Group 1 included patients with positive routine cultures who were subsequently treated with antibiotics; group 2 included patients with positive routine cultures who were not treated with antibiotics; group 3 included patients in which routine cultures were negative; and group 4 included patients in which no routine cultures were obtained. We then used inpatient and outpatient records to tabulate all patients who were rehospitalized for a late deep infection or antibiotic complication. Late deep infection was defined as infection requiring rehospitalization or reoperation. The groups were then compared using χ2 test with calculated 95% confidence intervals. Student t test was performed on all independent variables. Significance level was set at P <0.05 for all tests.
Results: 58 of the 162 included patients had routine cultures obtained (36%). Of those with routine cultures, 18 were positive (31%), while 40 cultures were negative (69%). Overall, 22 patients developed a late infection (14%). 7 of the 14 patients (50%) in group 1 (routine cultures positive, treated with antibiotics) developed a late infection (24%, 76%). 4 of the 18 patients (22%) in group 2 (routine cultures positive, no antibiotic treatment) developed a late infection (7%, 48%). 5 of the 40 patients (12.5%) in group 3 (routine cultures negative) developed a late infection (5%, 28%). 3 of the 104 patients (3%) in group 4 (no routine cultures obtained) developed a late infection (0.1%, 9%). The most common organism obtained on routine culture and causing late infection was Klebsiella pneumoniae. Of the 24 patients with positive routine cultures treated with antibiotics, a significant number of these patients (29%) experienced an antibiotic complication (P <0.0001) (14%, 54%), with 5 (21%) requiring rehospitalization specifically for their antibiotic complication (7%, 42%). The most common antibiotic complications were renal failure and neutropenia. Patients treated for an infection underwent a significantly increased number of invasive procedures than those not treated (P <0.0001).
Conclusion: Obtaining routine intraoperative cultures for presumed aseptic secondary orthopaedic procedures appears to lead to a high risk for antibiotic-related complications without reducing the rate of late deep infection.
Alphabetical Disclosure Listing (808K PDF)
• The FDA has not cleared this drug and/or medical device for the use described in this presentation (i.e., the drug or medical device is being discussed for an “off label” use). ◆FDA information not available at time of printing. Δ OTA Grant.