Aims. This study aims to determine difference in annual rate of early-onset (≤ 90 days) deep surgical site infection (SSI) following primary total knee arthroplasty (TKA) for osteoarthritis, and to identify risk factors that may be associated with infection. Methods. This is a retrospective population-based cohort study using prospectively collected patient-level data between 1 January 2013 and 1 March 2020. The diagnosis of deep SSI was defined as per the Centers for Disease Control/National Healthcare Safety Network criteria. The Mann-Kendall Trend test was used to detect monotonic trends in annual rates of early-onset deep SSI over time. Multiple logistic regression was used to analyze the effect of different patient, surgical, and healthcare setting factors on the risk of developing a deep SSI within 90 days from surgery for patients with complete data. We also report 90-day mortality. Results. A total of 39,038 patients underwent primary TKA for osteoarthritis during the study period. Of these, 275 patients developed a deep SSI within 90 days of surgery, representing a cumulative incidence of 0.7%. The annual infection rate did not significantly decrease over the seven-year study period (p = 0.162). Overall, 13,885 (35.5%) cases were excluded from the risk analysis due to missing data. Risk factors associated with early-onset deep SSI included male sex, American Society of Anesthesiologists grade ≥ 3, blood transfusion, acute length of stay, and surgeon volume < 30 TKAs/year. Early-onset deep SSI was not associated with increased 90-day mortality. Conclusion. This study establishes a reliable baseline infection rate for early-onset deep SSI after TKA for osteoarthritis using robust Infection Prevention and Control surveillance data, and identifies several potentially modifiable risk factors. Cite this article: Bone Joint J 2023;105-B(9):971–976

Introduction. Antibiotic-impregnated bone cement (AIBC) has been used for decades to treat and prevent post-operative infections in joint arthroplasty. Local delivery of antibiotics may theoretically have a bactericidal effect, however evidence supporting this is controversial and literature suggests its prophylactic use in primary total knee arthroplasty (TKA) is seldom justified. With evolving standards of care, historical data is no longer relevant in addressing the efficacy of AIBC in the contemporary TKA. The purpose of this study was to evaluate outcomes following primary TKA using AIBC and regular non-AIBC by comparing rates of surgical site infection (SSI) and prosthetic joint infection (PJI). Methods. A retrospective review was conducted of all cemented primary TKA procedures from a large institutional database between January 1, 2015 and December 31st, 2016. This identified 6,073 cases, n=2,613 in which AIBC was used and n=3,460 cases using bone cement without antibiotics. Patients were stratified into low risk and high-risk groups based on age (>65 years), BMI (>40), and Charlson Comorbidity Index (CCI; >3). Medical records were reviewed for diagnoses of SSI (skin and superficial wound infections) and PJI (deep joint infections requiring surgery) over a 2-year postoperative period. Univariate analysis and multivariate regression models were used to ascertain the effects of cement type, patient factors (age, gender, BMI, CCI), operative time, and length of stay on infection rates. Additionally, mixed models (adjusted for gender, age, race, BMI, and CCI) were built to account for surgeon variability. Results. The use of AIBC and risk group distributions were equal across the study period and no collinearity was found between the study variables. The SSI rate was 3.0% and the PJI rate was 0.8% in the total study population. Univariate analysis showed there was no significant difference in SSI rates with AIBC compared to non-AIBC (3.3% vs. 2.8%, p=0.278) or in PJI rates (1.0% vs. 0.7%, p=0.203). Multivariate logistic regression analysis adjusted for patient factors, operative time, and length of stay showed no significant difference in SSI rates with a procedure using AIBC compared to non-AIBC (OR=0.90; 95% CI, 0.66–1.23; p=0.515) and no significant difference in PJI rates (OR=1.01; 95% CI, 0.55–1.84; p=0.984). Mixed models also showed no difference in PJI rates with AIBC use after adjusting for surgeon variability as well as patient factors (gender, race, age, BMI, and CCI). Discussion. Prophylactic use of AIBC in primary TKA is not without consequence when considering the significant increase in cost and its potential side effects, namely organism specific antibiotic resistance and mechanical loosening. This study shows that even when adjusted for patient factors, procedure-related factors, and length of stay, there is no clinically significant decrease in infection rates with the use of AIBC in primary TKAs

Aims

To evaluate the influence of discharge timing on 30-day complications following total knee arthroplasty (TKA).

We reviewed 231 patients who had undergone total knee replacement with an AGC (Biomet) implant over a period of 2.5 years. After applying exclusion criteria and with some loss to follow-up, there were 144 patients available for study. These were divided into two groups; those who had received intra-articular steroid in the 11 months before surgery and those who had not.

There were three deep infections, all of which occurred in patients who had received a steroid injection. The incidence of superficial infection was not significantly different in the two groups. Five patients had undergone investigation for suspected deep infection because of persistent swelling or pain and all of these had received an intra-articular injection pre-operatively. We conclude that the decision to administer intra-articular steroids to a patient who may be a candidate for total knee replacement should not be taken lightly because of a risk of post-operative deep infection.