Timothy L. Tan
NEW YORK — Male gender, a diagnosis of diabetes and having native septic arthritis are factors that put patients with septic arthritis who undergo total joint arthroplasty at greater risk for developing prosthetic joint infection, a presenter said.
At the Musculoskeletal Infection Society (MSIS) Annual Open Scientific Meeting, Timothy L. Tan, MD, presented results of a retrospective study of patients who underwent 233 TJA procedures (124 total hip arthroplasties; 109 total knee arthroplasties) at four institutions and developed prosthetic joint infection (PJI).
“The [prior] treatment, we found that this does not influence the development of PJI after arthroplasty whether it is comparing an [irrigation and debridement] I&D vs. a two-stage or an arthroscopic vs. an open I&D,” Tan said.
Development of PJI as defined by MSIS criteria was the primary outcome. Infection was determined by extracting data from patients’ medical records regarding culture results, any prior treatments and other variables.
Tan said PJI rates in these patients are typically 1%, but have been reported to be as high as 6%.
In this study, he said, “Overall, the rate of PJI in this patient population was 12.4%. The most common reason for native septic arthritis was prior postoperative etiology. In the multivariate analysis, the risk factors for PJI development were male gender, a postoperative etiology and diabetes. Antibiotic-resistant organisms were significant in the unadjusted model but in the multivariate analysis, it was not significant.”
Concerning the role of prior surgical treatment in relation to PJI, there was no difference shown for prior two-stage exchange performed with a spacer or I&D, Tan said.
“The infection rate was 13% in the I&D group and the two-stage group was 8.4%” with no difference in the I&D group’s infection rate whether patients underwent arthroscopic or open I&D, he said.
“We then wanted to look at time from infection to arthroplasty to see if this had a role. We found that [a] patient with a PJI had a mean interval of 14 months, while patients who did not develop PJI had a mean interval of 22 months from initial septic arthritis infection to arthroplasty,” Tan said.
He noted the study had some limitations. These included the possibility it was underpowered, that 5% of patients underwent aspiration and treatment protocols of the participating institutions may have varied.
“Lastly, we found that [erythrocyte sedimentation rate] ESR and [C-reactive protein] CRP does not predict the development of PJI and has poor diagnostic utility at the time of conversion arthroplasty,” Tan said. – by Susan M. Rapp
Tan TL, et al. Total joint arthroplasty after septic arthritis: When can this be safely performed? Presented at: Musculoskeletal Infection Society Annual Open Scientific Meeting; Aug. 2-3, 2019; New York.
Disclosure: Tan reports no relevant financial disclosures.