What Are the Indications for Aspiration of a Possibly Infected Total Ankle Arthroplasty (TAA)?

Rationale

We performed a systematic review of the literature regarding the research question found above as recommended: A PubMed Search for the MeSH Terms (“arthrocentesis”[MeSH Terms] OR “arthrocentesis”[All Fields] OR (“joint”[All Fields] AND “aspiration”[All Fields]) OR “joint aspiration”[All Fields]) AND (“arthroplasty, replacement, ankle”[MeSH Terms] OR (“arthroplasty”[All Fields] AND “replacement”[All Fields] AND “ankle”[All Fields]) OR “ankle replacement arthroplasty”[All Fields] OR (“total”[All Fields] AND “ankle”[All Fields] AND “arthroplasty”[All Fields]) OR “total ankle arthroplasty”[All Fields]) was performed on February 16, 2018. A total of n = 10 results were found.

Additionally, a PubMed Search for the MeSH Terms (“infection”[MeSH Terms] OR “infection”[All Fields]) AND (“arthroplasty, replacement, ankle”[MeSH Terms] OR (“arthroplasty”[All Fields] AND “replacement”[All Fields] AND “ankle”[All Fields]) OR “ankle replacement arthroplasty”[All Fields] OR (“total”[All Fields] AND “ankle”[All Fields] AND “arthroplasty”[All Fields]) OR “total ankle arthroplasty”[All Fields]) was performed on February 17, 2018. A total of n = 200 results were found. After exclusion of irrelevant manuscripts or duplicates, only 4 publications remained that can be considered a “match” regarding a specific answer to the research question.

Investigation of a prosthetic joint for possible infection, including the ankle, commences with detailed history-taking, physical examination, and ordering a series of laboratory tests. There is no gold standard for diagnosis of periprosthetic joint infection (PJI), and because of this, we must rely on a combination of diagnostic techniques to reach or refute the diagnosis of PJI. The serum laboratory tests that should be ordered include erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and potentially other tests, such as d-dimer levels. If these laboratory tests are elevated or with normal serological tests and high clinical suspicion for infection, the next line of investigation is believed to be joint aspiration.

The synovial fluid obtained, if any, should be sent for analyses that include total white blood cell count, neutrophil count and the percentage of neutrophils, as well as analyses for biomarkers, such as leukocyte esterase and alpha-defensin. The joint aspirate is also cultured to identify the potential infecting pathogen.

Although the algorithm for investigation of PJI in hip and knee arthroplasty has been well studied and the optimal threshold for parameters, such as cell count and neutrophil differential, determined, there is little data related to PJI of total ankle arthroplasty (TAA). In the absence of such data, we believe that TAA should also be investigated in a similar fashion to hip and knee arthroplasty. In fact, our search determined that most studies related to TAA use the MusculoSkeletal Infection Society criteria and extrapolate data published in total hip and knee arthroplasty literature to TAA. ⁴ In one study, Alrashidi et al recommended that aspiration for synovial fluid analysis should be considered if the ESR and CRP are elevated. ¹ This has been corroborated by other studies in recent years, confirming the utility of aspiration to help gauge the presence of inflammation or infection around a TAA.^2,3,5

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