Stephen M. Petis MD MSc FRCSC1 and Steven J. MacDonald MD FRCSC2 1 Woodstock General Hospital, Woodstock, ON, Canada 2 London Health Sciences Centre, University Hospital, London, ON, Canada By 2030, it is predicted that 3.48 million primary TKAs will be performed each year in the United States.1 As the number of procedures performed continues to rise, the burden of PJI following TKA will rise concomitantly. PJIs are associated with patient morbidity and mortality, poor patient‐reported outcomes, and tremendous costs to the healthcare system.2–4 Any intervention that mitigates the risk of PJI following TKA would be worthwhile. The best available evidence includes three randomized, controlled trials.5–7 One of these trials is a level I (therapeutic) trial. The other two trials are graded as level II (therapeutic) despite their randomized study design because of lack of blinding and poor randomization technique. Impactful data are also available from large registry‐derived studies, graded as level IV (therapeutic) based on their retrospective design.8,9 Finally, there is a meta‐analysis of randomized controlled trials (RCTs; level I) that also seeks to answer this question. There are three randomized trials examining the clinical effectiveness of ALBC on PJI following TKA. Chiu et al. randomized 78 patients undergoing TKA to receive cement with or without 2 g of cefuroxime added to each 40 g batch of cement.5 The primary diagnosis was osteoarthritis in all cases, and every patient had been diagnosed with diabetes mellitus. At mean follow‐up of 50 months, there was a significant reduction in deep PJI for patients with ALBC (relative risk [RR] = 0.865; 95% confidence interval [CI]: 0.77–0.97; p = 0.021). However, this study had methodological and practical limitations, including lack of blinding, small sample size, and hybrid fixation technique (cementless femur and cemented tibia). Chiu et al. later published a series of 340 primary TKAs randomized to receive ALBC (178 knees) and cement without antibiotics (162 knees).6 The PJI rate was significantly lower in the group with ALBC (0% vs 3.1%, p = 0.024). Similarly, this study was limited by the lack of blinding, as well as generalizability, as the procedures were performed in an environment that was not optimized for sterility. In the largest trial to date on the topic, Hinarejos et al. randomized 3000 TKA patients to ALBC (n = 1483) versus plain cement (n = 1465).7 They found no significant difference in the deep infection rate between the two groups (1.4% in both, p = 0.96). In their meta‐analysis of RCTs, which included all of the above trials, Zhou et al. found no significant difference in deep or superficial infection rate.10 A large series from the Finnish Arthroplasty Register retrospectively examined 40 135 primary TKAs using a Cox regression analysis to determine risk factors for PJI.8 The risk of PJI was higher for cases without ALBC (hazard ratio [HR] = 1.35; 95% CI: 1.01–1.18), as well as for cases with intravenous (IV) antibiotics alone compared to IV antibiotics with ALBC (HR = 1.42; 95% CI: 1.08–1.88). Patients with secondary osteoarthritis (HR = 1.86; 95% CI: 1.12–3.11) and rheumatoid arthritis (HR = 1.86; 95% CI: 1.31–2.63) were identified as having a higher risk of PJI after primary TKA. A more recent registry review performed in Spain examined the effect of ALBC on infection rates in 1250 TKAs (555 with and 695 without ALBC).9 They found a significant reduction in PJI rates (RR = 0.37; 95% CI: 0.16–0.87; p = 0.019) after the introduction of ALBC. Interestingly, two other registry studies, one from New Zealand (n = 64 566 joints) and another from the United States (n = 56 216 knees) both found increased infection rate in those undergoing surgery with ALBC. Registry data should be interpreted cautiously, as the diagnosis of PJI cannot be confirmed, and the data output is limited by the initial accuracy of diagnostic coding at the time of treatment. In addition, registry data are naturally prone to selection bias.
35 Antibiotic Cement in Total Knee Arthroplasty
Clinical scenario
Top three questions
Question 1: For patients undergoing primary TKA, does the routine use of antibiotic-loaded bone cement (ALBC) reduce the rate of periprosthetic joint infection (PJI) compared to cement without antibiotics?
Rationale
Clinical comment
Available literature and quality of the evidence
Findings
Resolution of clinical scenario