Abstract
INTRO
Two-stage revision arthroplasty for PJI may make use of an antibiotic-loaded cement spacer (ACS), as successful long- term prevention of reinfection have been reported using this technique.[i] However, there is little data on systemic complications of high-dose antibiotic spacers. Acute kidney injury (AKI) is of clinical significance, as the drugs most commonly utilized, vancomycin and aminoglycosides, can be nephrotoxic. We intended to determine the incidence of AKI in patients that underwent staged revision arthroplasty with an ACS, as well as to identify potential predisposing risk factors for the disease.
METHODS
Local databases of six different orthopaedic surgeons were retrospectively reviewed for insertion of either a static or articulating antibiotic cement spacer by from 2007–2017. Dose of antibiotic powder implanted, as well as IV antibiotic used, was collected from operative records. Demographics, comorbidities, and preoperative and postoperative creatinine and hemoglobin values were recorded from the EHR. AKI was defined by a more than 50% rise in serum creatinine from preoperative baseline to at least 1.4 mg/dL, as described by Menge et al.[ii] Variables were analyzed for the primary outcome of AKI within the same hospital stay as insertion of the ACS. Categorical variables were analyzed with Chi-Square test, and continuous variables with univariate logistic regression.
RESULTS
75 patients (39 M, 36 F) receiving an ACS were identified, with a mean age of 70.0 (SD=10.6) and a mean BMI of 31.3 (SD=7.3). Incidence of in-hospital AKI was 13.3%. Patients reached AKI at a mean 6.7 days (SD=4.5), during a median length of stay of 13.5 days (IQR=21.8). No significant correlation was found between AKI and the variables of age (p=.430), BMI (p=.569) or gender (p=.181). AKI was also not associated with increased dose of vancomycin (p=.416), tobramycin (p=.440), or gentamycin (p=.846) within the cement spacer, or the comorbidities of hypertension (p=.094), diabetes (p=.146), coronary artery disease (p=1.00) and renal disease (p=.521). However, decreased baseline hemoglobin showed significantly increased risk for AKI (OR=1.67, p =.049), and increased creatinine showed a trend (OR=2.9, p=.059). Percentage of hemoglobin decrease (preoperative to postoperative) did not increase odds for AKI (p=.700).
CONCLUSION
The incidence of acute kidney injury in patients that receive antibiotic cement spacers is relatively high when compared to the data reported in primary TKA.ii,[iii] Our results suggest that patient related risk factors, such as low preoperative hemoglobin, may be involved in the etiology of AKI in this population. Therefore, it may be clinically appropriate to monitor anemic patients for AKI when implanting an ACS.
