Paper of the Week: Risk of Periprosthetic Infection Following Intra-Articular Corticosteroid Injections After Total Knee Arthroplasty

Roecker Z, Quinlan ND, Browne, JA, Werner BC

The Journal of Arthroplasty 35 (2020): 1090-1094
DOI: 10.1016/j.arth.2019.11.017

Summary by: Samuel Clarkson, MD

Intraarticular corticosteroid injections are commonly used in the nonoperative and preoperative management of knee osteoarthritis. Although less common, corticosteroid injections are also occasionally used in the postoperative period following total knee arthroplasty (TKA). Despite its efficacy, recent literature has demonstrated an increased risk of periprosthetic joint infection (PJI) if an injection is performed within three months prior to TKA [1]. However, prior studies that examined safety in the postoperative period are conflicting single center studies limited by a lack of control group [2] or small sample size [3].

In this study, Roecker et al. used a large national database to examine the risk of PJI after postoperative corticosteroid injection following TKA. The authors evaluated a retrospective cohort of 166,946 patients from the Humana database undergoing TKA from 2007 to 2017. Patients who received a postoperative corticosteroid injection (n=5,628; 3.4%) were compared to a 2:1 matched cohort control group of patients who did not receive a postoperative injection.

In all three outcome measures studied by the authors, there was a significant association between postoperative injection and PJI:

1. Increased rate of PJI diagnosis at 6-month (1.9% vs. 1.1%; OR 1.85, p < 0.0001)
2. Increased rate of PJI diagnosis at 1-year (2.4% vs. 1.4%; OR 1.97, p < 0.0001)
3. Increased rate of ipsilateral procedure for PJI at any time point (1.8% vs. 0.4%; OR 7.36, p < 0.0001)

The authors acknowledged the limitations of using a large national database. Most significantly, the outcome measures were dependent upon what was available in the database. First, there was no uniform classification used for diagnosis of PJI, determination was done by the individual surgeon. Second, the absence of laterality in ICD-9 codes created the possibility that 6-month and 1-year PJI diagnosis was not always the initial joint injection.

Despite these limitations, the authors concluded that despite efficacy in managing pain and stiffness, postoperative corticosteroid injections following TKA are associated with subsequent PJI.

References:

1. Richardson SS, Schairer WW, Sculco TP, Sculco PK. Comparison of Infection Risk with Corticosteroid or Hyaluronic Acid Injection Prior to Total Knee Arthroplasty. J Bone Joint Surg Am 2019;101:112–8. https://doi.org/10.2106/JBJS.18.00454.
2. Mills ES, Elman MB, Foran JRH. The Risk of Acute Infection Following Intra-articular Corticosteroid Injection Into a Pre-existing Total Knee Arthroplasty. J Arthroplasty 2018;33:216–9. https://doi.org/10.1016/j.arth.2017.07.029.
3. Klement MR, Luzzi AJ, Siddiqi A, Valichka K, Sharkey PF. Intra-articular Corticosteroid Injection Following Total Knee Arthroplasty: Is It Effective? J Arthroplasty 2019;34:303–8. https://doi.org/10.1016/j.arth.2018.10.033.