The Routine Use of Atypical Cultures in Presumed Aseptic Revisions Is Unnecessary

Abstract

Background In presumed aseptic hip and knee revisions, it is common practice to send intraoperative cultures to screen for occult infection. Currently no guidelines exist for the routine use of acid-fast bacillus (AFB) and fungal cultures in this setting. Questions/purposes We established (1) the rate of positive fungal and AFB cultures in aseptic hip and knee revision arthroplasties, (2) factors associated with positive fungal and AFB cultures, (3) the likelihood that positive cultures represent true-positive results, and (4) the hospital charges of sending fungal and AFB cultures routinely. Methods We retrospectively evaluated all 1717 presumed aseptic hip and knee revisions performed from January 2006 to November 2011: 1139 patients had at least one intraoperative fungal culture and 1133 patients had at least one intraoperative AFB culture, with 923 and 920, respectively, achieving 1-year followup. The Musculoskeletal Infection Society criteria were used to classify subsequent infections. We attempted to identify risk factors for positive cultures. Results We observed six (0.5%) patients with positive AFB cultures and 19 (1.7%) with positive fungal cultures. Patients undergoing reimplantation procedures were more likely to have a positive fungal culture. The true-positive rate was 0% and 0.1% for AFB and fungal cultures, respectively. The total hospital charges for these cultures over the time frame of our study were USD 1,315,533. Conclusions Given the extremely low rate of true-positive AFB and fungal cultures in presumed aseptic revision joint arthroplasty and the charges associated with maintaining these cultures, we believe their routine use is unwarranted.

Management of Resistant, Atypical and Culture-negative Periprosthetic Joint Infections after Hip and Knee Arthroplasty

“…If preoperative cultures are negative or if P. acnes , fungi or mycobacterium are suspected, prolonged culture incubation for 14 to 21 days should be considered [ 78 ]. Cultures for mycobacterium and fungi should not be routine, since that practice is not cost-effective [ 79 ]. If available, sonication of the retrieved prosthesis can retrieve viable microorganisms from biofilm and improve the sensitivity of cultures [ 54 ].…”

Diagnosis of Periprosthetic Joint Infection

“…Evidence has shown that routine AFB and fungal testing in presumed aseptic cases does not yield clinically important findings, nor is it cost‐effective …”

What Strategies Can Be Implemented to Help Isolate the Causative Organism in Patients With Infection of the Foot and Ankle?

“…Evidence has demonstrated that routine AFB and fungal testing in presumed aseptic cases does not yield clinically important results nor is it cost-effective. 43 However, when mycobacterium and fungal organisms are considered, AFB and fungal-selective media must be included, and it should be noted that prolonged culture may be required according to national laboratory standards. One should expand diagnostic testing to include tissue samples for histologic examination, especially in patients with high clinical suspicions of infection.…”