OBJECTIVES: As a result in the rise in number of total joint arthroplasty (TJA) procedures there has been a similar increase in the incidence of periprosthetic joint infection (PJI) and associated revisions. PJI accounts for 25% and 15% of failed total knee arthroplasties (TKA) and total hip arthroplasties (THA), respectively. Standard of care for preoperative diagnosis of PJI in revision TJA is typically a Serum C-Reactive Protein (Serum CRP) test. However, the reliability of Serum CRP has been questioned due to varied reporting of specificity and sensitivity ranges (Sensitivity: 82%-96.6%; Specificity: 68.1%-88%). To address this issue, a novel Alpha Defensin detection test has been developed. The economic impact of Serum CRP’s performance with and without this Alpha Defensin detection test has not been fully characterized.

METHODS: This budget impact model leverages evidence from a commercial payer database (IBM MarketScan^® Treatment Pathways) and peer-reviewed literature to consider both current PJI diagnostic costs and avoidance of unnecessary revision TJA. The model is built on two components: 1) calculating diagnostic test costs; and 2) quantifying unnecessary TJA revision costs due to misdiagnosed PJI.

RESULTS: Combining Serum CRP with the Alpha Defensin detection test resulted in savings of $915 and $503 per TKA and THA, respectively. In addition, combining the two diagnostic tests resulted in fewer unnecessary revision TJA procedures per patient versus the Serum CRP test alone (TKA – 0.056 two-stage revisions, 0.024 misdiagnosed one-stage revisions; THA – 0.034 two-stage revisions, 0.011 misdiagnosed one-stage revisions).

CONCLUSIONS: This novel Alpha Defensin detection test provides an accurate and rapid result to aid in PJI diagnosis and reduces the economic and clinical burden associated with unnecessary revision TJA procedures due to misdiagnosed PJI. This diagnostic test may offer demonstrable economic value to patients, healthcare providers and payers.