SLR - October 2018 - Natalia Cardona

Postoperative Blood Glucose Levels Predict Infection After Total Joint Arthroplasty

Reference: Kheir, MM, Tan, TL, Kheir, M, Maltenfort, MG, & Chen, AF. Postoperative Blood Glucose Levels Predict Infection After Total Joint Arthroplasty. J Bone Joint Surg AM. 2018 Aug 15;100(16): 1423–1431.

Scientific Literature Review

Reviewed By: Natalia Cardona, DPM
Residency Program: Northwest Medical Center, Margate, FL     

Podiatric Relevance: As any podiatric surgeon is aware, infection is a serious complication after elective surgery, and it is especially concerning when a total joint replacement is involved. Uncontrolled diabetes mellitus leading to hyperglycemia is one of the factors demonstrated to increase the risk of periprosthetic joint infection since increased serum glucose levels impair immune function and create an optimal medium for bacterial growth. It is known that postoperative infections lead to increased morbidity, mortality, length of hospital stay and healthcare costs. This study aimed to investigate if postoperative blood glucose levels are associated with periprosthetic joint infection after total joint arthroplasty.  

Methods: This was a single-institution retrospective case study that was conducted on 24,857 primary total joint arthroplasties performed from 2001 to 2015. Of these, 13,196 had a minimum follow-up of one year. The authors analyzed the postoperative day 1 morning fasting blood glucose levels and correlated that with the incidence of periprosthetic joint infection, as defined by the International Consensus Group on Periprosthetic Joint Infection. All patients received standard perioperative management for infection prophylaxis. Intravenous antibiotics were given within one hour prior to incision and for 24 hours postoperatively. The authors used a multivariable analysis to determine the influence of several important variables on infection. Some of the variables collected included length of stay, perioperative antibiotics and thromboprophylaxis, to name a few.         

Results: The authors noted that the rate of periprosthetic joint infection increased linearly from blood glucose levels of greater than or equal to 115 mg/dL. Greater than that threshold, patients are at significant risk of developing periprosthetic joint infection with the odds increasing by a factor of 1.004 per 1 mg/dL increments. According to the analysis, the blood glucose levels were significantly associated with periprosthetic joint infection. The optimal blood glucose threshold to reduce the likelihood of periprosthetic joint infection was 137 mg/dL. The periprosthetic joint infection rate in the entire cohort was 1.59 percent (1.46 percent in patients without diabetes compared with 2.39 percent in patients with diabetes). There was no significant association between blood glucose level and periprosthetic joint infection in patients with diabetes, although the authors stated that they noticed a linear trend.

Conclusions: The authors determined that the relationship between postoperative blood glucose levels and periprosthetic joint infection increased linearly, with an optimal cutoff of 137 mg/dL. Interestingly, the authors note that this study should promote a cautionary report for patients without diabetes undergoing elective orthopaedic procedures, as they may also encounter elevated blood glucose levels just from the stress of surgery, and they are not typically treated for hyperglycemia in the hospital setting. They note that immediate and strict postoperative glycemic control may be critical in reducing postoperative complications, as even mild hyperglycemia was significantly associated with periprosthetic joint infection. 

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