SLR - February 2018 - Richard C. Harris III

Intraoperative Frozen Section Histology: Matched for Musculoskeletal Infection Society Criteria

Reference: Kwiecien G, George J, Klika AK, Zhang Y, Bauer TW, Rueda CA. Intraoperative Frozen Section Histology: Matched for Musculoskeletal Infection Society Criteria. J Arthroplasty. 2017;32(1):223–227.

Scientific Literature Review

Reviewed By: Richard C. Harris III, DPM 
Residency Program: UF Health Jacksonville, Jacksonville, FL

Podiatric Relevance: A periprosthetic joint infection (PJI) is one of the most challenging complications following lower-extremity joint arthroplasty. What makes it even more difficult is the lack of a “gold standard” for diagnosing this dreaded complication. The question posed is then what tests or criteria can be utilized to define a PJI? The Musculoskeletal Infection Society (MSIS) developed a list of criteria for diagnosing PJI that has recently gained popularity. Although beneficial, the MSIS criteria are not without drawbacks as they are often incomplete at the time of surgery. Preoperative joint aspiration cultures yield inferior results when compared with intraoperative tissue microbiology. Because intraoperative cultures are available two to three days after surgery, surgeons often end up relying on frozen section histology in planning treatment. Also, serology markers, such as ESR/CRP, may be elevated in the absence of a PJI if there are coexistent inflammatory conditions, such as rheumatoid arthritis, urinary tract infections and soft-tissue infections. Thus, frozen section has become a promising and important tool in reconstructive surgery due to its cost effectiveness, simplicity and timely results.

Methods: A retrospective review of 200 procedures consisting of revision total hip or total knee arthroplasty due to PJI or mechanical failure. An experienced pathologist analyzed multiple sections from each site, and the number of polymorphonuclear cells (PMNs) per high power fields (HPFs) was determined in multiple separate microscopic fields. Acute inflammation suggestive of infection was reported when at least five neutrophils in at least three HPFs were seen on the frozen section slides (modified Mirra’s criterion). Results of frozen sections were compared to the modified MSIS criteria. The discrepancy rate between frozen and permanent sections was also calculated.

Results: Of the 421 frozen histology samples from the 200 cases, 75 were positive for infection (17.8 percent). Perioperative cultures from the periprosthetic tissue/synovial fluid were positive in 27 cases (13.5 percent).

Staphylococcus aureus (n = 9/27) and coagulase negative Staphylococcus (n = 6/27) were the most commonly isolated pathogens. Frozen sections resulted in the following: sensitivity 73.7 percent, specificity 98.8 percent, positive predictive value 94.1 percent, negative predictive value 93.3 percent and accuracy 94 percent. There were 10 discrepancies between the results of frozen and permanent sections, thereby yielding a 97.6 percent concordance.

Conclusions: PJI can lead to devastating outcomes, such as implant failure, conversion to complex salvage arthrodesis and limb loss. Thus, it is imperative that the surgeon be able to differentiate between septic and aseptic joint failure as management of these two is vastly different. A multitude of tests are available for diagnosing PJI; however, the limited sensitivity and specificity of these tests pose difficulties in distinguishing between PJI and other causes of joint failure. This study contributes to the ongoing debate as it determined when matched to the MSIS criteria, intraoperative frozen section histology yields a high specificity, positive predictive value, negative predictive value, accuracy and moderate sensitivity. They were also able to determine a low discrepancy rate between frozen and permanent sections, thus lending further credence to frozen section as an effective diagnostic test for PJI.

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