Distinguishing Periprosthetic Crystalline Arthropathy from Infection in Total Knee Arthroplasty: A Systematic Review

Abstract

Distinguishing periprosthetic crystalline arthropathy from periprosthetic joint infection (PJI) remains a diagnostic challenge as both symptom presentation and diagnostic tests overlap. Accurate differentiation is important as treatment plans vary significantly. We sought to systematically review all cases of total knee arthroplasty (TKA) periprosthetic crystalline arthropathy reported in the literature and summarize clinical, diagnostic, and operative findings in the context of guidelines for diagnosing PJI. The goal of this systematic review is to determine the amount of diagnostic overlap and to identify best practices for differentiating between these two diagnoses. MEDLINE and Google Scholar were searched to identify cases of crystalline arthropathy following TKA. Case reports were reviewed for patient characteristics, clinical symptoms, physical exam, laboratory results, and treatment outcomes. These findings were summarized across patients and dichotomized based on current thresholds for diagnosing PJI according to Musculoskeletal Infection Society criteria. Twenty-six articles were identified which included 42 cases of periprosthetic crystalline arthropathy (17 gout, 16 pseudogout, one both, and eight not specified). Of these cases, 25 presented over 1 year after their index arthroplasty and 15 had no prior history of crystalline arthropathy. Only six cases had a superimposed infection based on aspiration or intraoperative cultures. For cases without a culture-positive infection, several diagnostic tests overlap with PJI thresholds: 95% of patients had C-reactive protein greater than 1 mg/dL, 76% had an erythrocyte sedimentation rate greater than 30 mm/hour, 91% had a synovial white blood cell greater than 3,000 cells, and 76% had a synovial polymorphonuclear cells percent greater than 80%. Patients without co-infection were managed with non-steroidal anti-inflammatory drugs, colchicine, allopurinol, steroids, or a combination of these treatments and most had complete resolution of symptoms within 1 week. Commonly used markers of PJI fail to reliably distinguish periprosthetic crystalline arthropathy from infection. Though clinical judgement and consideration of the implications of delayed treatment for acute PJI remain paramount, in the setting of synovial crystals, surgeons may wish to consider this alternate etiology as the source of the patient's clinical symptoms.

Diagnosis Dilemma, Culture-Negative Periprosthetic Hip Infection Versus Acute Gouty Arthritis

“…In addition, serum levels for WBC, ESR, and CRP demonstrate a similar pattern in both acute gout and septic arthritis. Bradley et al found significant overlap in diagnostic tests with 95% of patients having a CRP greater than 1 mg/dL, 76% with an ESR greater than 30 mm/h, 91% with synovial WBC greater than 3,000 cells, and 76% with a percentage of synovial polymorphonuclear cells greater than 80% 7 . In total, nearly two-thirds (64%) met criteria for PJI, as per the Musculoskeletal Infection Society guidelines.…”

“…Exceedingly few cases of gout involving the hip, particularly after THA, have been reported. A recent meta-analysis identified 26 articles and 42 cases of gout associated with TKA while only 3 cases of acute gouty arthritis associated with THA have been reported [7][8][9][10] . We present the case of acute gouty arthritis in a patient with a history of a multiply revised THA.…”

Pseudogout After Total Knee Arthroplasty Meeting Minor Criteria for Infection Treated by Polyethylene Exchange

“…3,4 The clinical presentation of periprosthetic crystalline arthropathy, which includes both gout and pseudogout, is similar to PJI with underlying symptoms consisting of erythema, swelling, and pain in the affected joint. 5 While total knee arthroplasty (TKA) has a high survivorship, infection is a devastating complication. 6,7 Based on Medicare data, the infection rate in the first 2 years following TKA is 1.55% with an additional 0.46% in years 2-10.…”

“…8 Although the incidence is unknown, there has been minimal reporting of periprosthetic crystalline arthropathy following TKA in the literature. 5,9 While pseudogout in a joint after arthroplasty is a rare phenomenon, it is difficult to distinguish from infection and could also present with a concomitant infection. 5,10,11 In this unique case, we present an elderly patient who developed her first episode of pseudogout at 75 years of age, which was 17 years after her primary TKA leading to an isolated polyethylene exchange.…”

“…5,9 While pseudogout in a joint after arthroplasty is a rare phenomenon, it is difficult to distinguish from infection and could also present with a concomitant infection. 5,10,11 In this unique case, we present an elderly patient who developed her first episode of pseudogout at 75 years of age, which was 17 years after her primary TKA leading to an isolated polyethylene exchange. The patient provided informed consent for publication of this article.…”