Debridement, antibiotics, and implant retention in infected shoulder arthroplasty caused by Serratia marcescens: a case report

Periprosthetic joint infection (PJI) is one of the most devastating complications that can occur after shoulder arthroplasty. Although staged revision arthroplasty is the standard treatment in many cases, surgical intervention with debridement, antibiotics, and implant retention (DAIR) can be an effective option for acute PJI. We report a complex case of infected reverse shoulder arthroplasty (RSA) in a 73-year-old male. The patient had been previously treated for infected nonunion of a proximal humerus fracture caused by methicillin-resistant Staphylococcus epidermidis. He presented with a sinus tract 16 days after the implantation of RSA and was diagnosed with PJI caused by Serratia marcescens. The patient was successfully treated with DAIR and was free of infection at the last follow-up visit at four years postoperatively.

Deep infection after hip hemiarthroplasty: risk factors for infection and outcome of treatments

Aims Deep surgical site infection (SSI) remains an unsolved problem after hip fracture. Debridement, antibiotic, and implant retention (DAIR) has become a mainstream treatment in elective periprosthetic joint infection; however, evidence for DAIR after infected hip hemiarthroplaty is limited. Methods Patients who underwent a hemiarthroplasty between March 2007 and August 2018 were reviewed. Multivariable binary logistic regression was performed to identify and adjust for risk factors for SSI, and to identify factors predicting a successful DAIR at one year. Results A total of 3,966 patients were identified. The overall rate of SSI was 1.7% (51 patients (1.3%) with deep SSI, and 18 (0.45%) with superficial SSI). In all, 50 patients underwent revision surgery for infection (43 with DAIR, and seven with excision arthroplasty). After adjustment for other variables, only concurrent urinary tract infection (odds ratio (OR) 2.78, 95% confidence interval (CI) 1.57 to 4.92; p < 0.001) and increasing delay to theatre for treatment of the fracture (OR 1.31 per day, 95% CI 1.12 to 1.52; p < 0.001) were predictors of developing a SSI, while a cemented arthroplasty was protective (OR 0.54, 95% CI 0.31 to 0.96; p = 0.031). In all, nine patients (20.9%) were alive at one year with a functioning hemiarthroplasty following DAIR, 20 (46.5%) required multiple surgical debridements after an initial DAIR, and 18 were converted to an excision arthroplasty due to persistent infection, with six were alive at one year. The culture of any gram-negative organism reduced success rates to 12.5% (no cases were successful with methicillin-resistant Staphylococcus aureus or Pseudomonas infection). Favourable organisms included Citrobacter and Proteus (100% cure rate). The all-cause mortality at one year after deep SSI was 55.87% versus 24.9% without deep infection. Conclusion Deep infection remains a devastating complication regardless of the treatment strategy employed. Success rates of DAIR are poor compared to total hip arthroplasty, and should be reserved for favourable organisms in patients able to tolerate multiple surgical procedures. Cite this article: Bone Jt Open 2021;2(11):958–965.

111. Duration of Antibiotic Therapy after Debridement and Implant Retention in Patients with Periprosthetic Joint Infections

Background Debridement, antibiotics, and implant retention (DAIR) is appropriate for select acute postoperative and hematogenous periprosthetic joint infections (PJIs). However, the optimal duration of antimicrobial therapy in patients treated with DAIR has not been defined. Therefore, we aimed to identify the ideal duration of parenteral and oral antibiotics after DAIR. Methods We performed a retrospective study of patients &gt;18 years of age with hip or knee PJI managed with DAIR between January 1, 2008, and December 31, 2018, at Mayo Clinic. PJI was defined using criteria adapted from the International Consensus Meeting on PJI. The outcome was defined as either PJI recurrence or unplanned reoperation due to infection. Joint-stratified Cox proportional hazards regression models with time-dependent covariates were used to assess nonlinear effects of antibiotic duration. Hazard ratios were computed based on prespecified time points for comparison, whereas p-values represented the overall effect across the entire range of durations. Results There were 247 unique episodes of PJI in 237 patients during the study period. Parenteral antibiotics were given in 99.2% of cases (n=245). This was followed by chronic oral antibiotic suppression in 92.2% (n=226) with a median duration of 2.2 years (1.0-4.1). DAIR failed in 65 cases over a median follow-up of 4.4 years, with a 5-year cumulative incidence of 28.1%. After adjustment for risk factors, there was no significant association between duration of parenteral antibiotics and treatment failure (p=0.203), with no difference between four versus six weeks (HR 1.11; 95% CI 0.71-1.75) (Figure 1). However, both use and longer duration of oral antibiotic therapy was associated with a lower risk of failure (p=0.006). To account for the possibility that this association was driven by results during early follow-up, conditional analyses at one- and two-year follow-up were performed. Both showed a significantly lower risk for a longer duration of antibiotics (Figure 2). Figure 1. Time-Dependent Analysis of Parenteral Antibiotic Duration Figure 2. Time-Dependent Analysis of Oral Antibiotic Suppression Duration Conclusion After DAIR, efficacy from four weeks of parenteral antibiotics was no different from six weeks when followed by chronic oral antibiotic suppression. Our results could not establish an optimal duration but suggested that continuing suppression portends a lower risk of failure of DAIR. Disclosures Elie Berbari, MD, Uptodate.com (Other Financial or Material Support, Honorary unrelated to this work) Matthew P. Abdel, MD, Stryker and AAOS Board of Directors (Board Member, Other Financial or Material Support, Royalties) Aaron J. Tande, MD, UpToDate.com (Other Financial or Material Support, Honoraria for medical writing)

255. Utility of Magnetic Resonance Imaging in Predicting Failure of DAIR (Debridement, Antibiotics, and Implant Retention) for Treatment of Periprosthetic Joint Infection

Background Debridement, antibiotics, and implant retention (DAIR) is commonly utilized to treat acute periprosthetic joint infection (PJI) where thorough debridement of affected tissues is considered essential. Small case series describe occurrences where PJI spreads into adjacent tissues (iliopsoas recess in hips; neurovascular bundle in knees) and bone (osteomyelitis). Surgeons often cite adjacent tissue/bone infiltration as a poor predictor for DAIR. We sought to evaluate if the presence of adjacent tissue/bony lesions on preoperative magnetic resonance imaging (MRI) was associated with poorer DAIR outcomes. Methods MSIS criteria-positive hip (n=22) and knee (n=12) PJI cases in our institution from 2010-2020, with preoperative MRI prior to DAIR treatment, were evaluated. Demographics, microbiology, chronicity, and host grade were recorded. MRIs were assessed by two board-certified radiologists blinded to treatment outcomes, scoring images based on the presence of 18 distinct findings. Inter-rater reliability was calculated using bias adjusted Kappa scores. Failure was defined as repeat surgery for PJI. Univariate analysis and logistic regression were used to determine predictors of DAIR success at 90 days and 2 years. Results When comparing successful and non-successful hip PJI cases, the presence of a psoas recess fluid collection on MRI was significantly predictive of a higher rate of treatment failure at 2 years (odds ratio=0.12; p = 0.045), with a moderate adjusted kappa score of 0.5. With regard to knee PJI cases, capsular disruption (40% [2/5] vs 100% [7/7], p= 0.046) and patellar tendon disruption (25% [1/4] vs 100% [8/8], p = 0.018) were independently associated with higher 90-day failure. However, knee MRI findings were not predictive of failure using regression. Conclusion In this preliminary study, preoperative MRI findings anecdotally linked with PJI treatment failure could be reliably identified. However, few predicted DAIR failure. Further studies are needed to clarify the role of MRI in predicting PJI treatment success. Disclosures All Authors: No reported disclosures

239. Sex Differences in Prosthetic Joint Infection

Background Male sex has been demonstrated to be a non-modifiable risk factor for prosthetic joint infection (PJI) incidence in multiple studies. Given the known anatomical, genetic, and immunological differences between sexes, we compared the clinical characteristics of PJI among men and women. Methods A retrospective cohort of total hip and knee arthroplasty PJIs from 2009 to 2019 were identified using a single institution PJI database. Included cases met the 2013 MSIS criteria. Microbiology, acuity (defined by implant age and symptom days), and surgical outcomes were collected. Success was defined as no further PJI surgery at two years. Continuous variables were tested with either Student’s t test or Mann-Whitney U test. Categorical variables were tested with either Chi-squared test or Fisher’s exact test. Results We identified 1052 PJI patients, of whom 463 (44.0%) were women. In univariate analysis of the total cohort, women were younger (68.1 ± 11.2 vs 66.1 ± 11.8 years, p=0.01), had higher BMI (30.8 ± 7.78 vs 29.8 ± 6.0, p=0.04), and had a higher culture-negative rate (14.5% vs 9.0%, p &lt; 0.01) than men, but no difference was noted in Charlson Comorbidity Index (Table 1). Among hip PJIs, women were likelier than men to present with acute PJI (15.9% vs 8.7%, p=0.03). There were no differences in debridement, antibiotics, and implant retention (DAIR) utilization (48.2% vs 44.1%, p=0.067), and overall treatment success (72.1% vs 71.6%, p=0.9), nor in any subanalysis of acute, hip, or knee PJIs. Conclusion Although females may present differently when diagnosed with PJI, overall outcomes and outcomes with respect to acuity and type of septic revision did not clearly differ in this single-center cohort. Further research in larger cohorts, including additional biomarkers and socioeconomic variables, may further elucidate relationships between sex and PJI characteristics including culture-negativity and symptom acuity. Disclosures All Authors: No reported disclosures

248. Outcomes of Patients with Prosthetic Septic Arthritis with Debridement and Implant Retention

Background IDSA has published guidelines for the diagnosis and management of prosthetic joint infection (PJI). However, we have observed significant variability in the interpretation and application of these guidelines with respect to the management of those with PJI following debridement and implant retention (DAIR). It is not clear if variations in antimicrobial management are affecting clinical outcomes. Methods We performed a retrospective review at an academic hospital in rural New Hampshire. We included all adult patients from 1/1/2017 to 12/31/2018 with PJI of hip or knee who underwent DAIR. The demographic data, microbiology data, antibiotics treatment and duration were collected. The primary endpoint was overall re-infection rate within 2 years of surgery. Secondary endpoint was re-infection rate stratified by organism and antimicrobial type and duration. Results A total of 26 patients were included in our study. 65% involved knee joint. 50% had late-onset infection ( &gt;12 months). The top organisms were Streptococcus spp. (34%), CoNS (26 %) and MSSA (18 %). 15% were associated with bacteremia. Ceftriaxone was the most common antibiotic used (54 %). 38 % of patients received Rifampin PO along with IV antibiotics. All patients received PO antibiotic(s) after completing the course of IV therapy, and 7 patients were also on concomitant rifampin PO. The duration of PO antibiotic therapy was varied. 30% of patients received PO antibiotics for 6 months post IV treatment. Life-long suppression therapy were noted in 9 patients. Treatment failure within 2 years occurred in 8 patients (31%). Among those, 75% had Staphylococcal infection. All patients required hardware removal except one patient who required amputation. 2 patients developed recurrent PJI after completing 6 months and one year of PO suppression therapy, one patient had a recurrent infection while on life-long suppression. Staphylococcal infection was significantly associated with treatment failure. Conclusion Treatment of PJI with DAIR is challenging. Despite long-term IV therapy followed by oral antibiotics, there was a high rate of treatment failure (31% in our study) particularly with Staphylococcal infection. There was no association of variation of treatments and outcomes in our small cohort. Disclosures All Authors: No reported disclosures

Comparison of the success rate after debridement, antibiotics and implant retention (DAIR) for periprosthetic joint infection among patients with or without a sinus tract

Background The relevance between the presence of a sinus tract and the failure risk after debridement, antibiotics and implant retention (DAIR) for periprosthetic joint infection (PJI) after hip or knee arthroplasty is still unclear. This study aimed to compare the success rate of DAIR between patients with or without a sinus tract and to explore the possible risk factors for failure after DAIR in patients with a sinus tract. Methods Consecutive DAIR cases for PJI after hip or knee arthroplasty between January 2009 and June 2019 with a minimum 1-year follow-up in two tertiary joint arthroplasty centers were included. Patients were classified into the sinus tract group and the non-sinus tract group according to the presence of a sinus tract. The success rate after DAIR were compared using Kaplan-Meier survival analysis. Potential risk factors for failure in the sinus group were also explored. Results One hundred seven patients were included. At a median 4.4 years of follow-up, 19 of 52 (36.5%) cases failed in the sinus tract group, while 15 of 55 (27.3%) cases failed in the non-sinus tract group. The 1-year and 5-year cumulative success rates were 71.2% (95% confidence interval (CI): 59.8-84.6%) and 56.8% (95% CI: 42.6-75.7%) in the sinus tract group, respectively, which were similar to the counterparts in the non-sinus tract group (P = 0.214). Among patients with a sinus tract, DAIR with the exchange of modular components showed a higher success rate (75.8% versus 47.4%, P = 0.038). Conclusions The presence of a sinus tract does not affect the success rate of DAIR. Modular component exchange in DAIR was proposed for patients with a sinus tract for an improved infection control rate.