Background: Periprosthetic joint infections (PJIs) represent a serious complication following total hip arthroplasty (THA) and are associated with significant morbidity. While recent data suggest that Enterobacter cloacae is an emerging source of PJI, characteristics and outcomes of E. cloacae-associated infections are rarely described. The study aimed to present and describe the findings and outcomes of E. cloacae-associated PJI in our department. Methods: This is a retrospective descriptive study of patients who underwent revision THA for E. cloacae-associated PJI between 2011 and 2020 and has a minimum follow-up of 2 years. Outcomes included organism characteristics as well as clinical outcomes, represented by the number of reoperations needed for PJI eradication and the Musculoskeletal Infection Society (MSIS) outcome reporting tool score. Of 108 revision THAs, 12 patients (11.1%) were diagnosed with E. cloacae-associated PJI. Results: The majority of cases had a polymicrobial PJI (n=8, 66.7%). Five E. cloacae strains (41.7%) were gentamicin-resistant. Six patients (50.0%) underwent 2 or more revisions, while 3 of them (25.0%) required 4 or more revisions until their PJI was resolved. When utilizing the MSIS outcome score, the first surgical intervention was considered successful (MSIS score tiers 1 and 2) for 5 patients (41.7%) and failed (tiers 3 and 4) for 7 patients (58.3%). Conclusions E. cloacae is emerging as a common source of PJI following hip arthroplasty procedures. The findings of our study suggest that this pathogen is primarily of polymicrobial nature and represents high virulence and poor postoperative outcomes, as represented by both an increased number of required revision procedures and high rates of patients with MSIS outcome scores of 3 and 4. When managing patients with E. cloacae-associated PJI, surgeons should consider these characteristics and inform patients regarding predicted outcomes

Background: Understanding the risk factors and outcomes of intraoperative periprosthetic femoral fractures (IPFF) during hip arthroplasty is crucial for appropriate perioperative management. Previous studies have identified risk factors for IPFF in total hip arthroplasty patients, but data for hip hemiarthroplasty (HA) is lacking. The aim of this study was to determine the age associated with increased rates of IPFF in patients undergoing HA. Methods: We retrospectively reviewed patients aged 65 years and above who underwent a cementless HA for a displaced femoral neck fracture and had a minimum of 1-year follow-up. Patients were stratified into five age groups (65–79, 80–84, 85–89, 90–94, and ≥ 95 years) and further divided into two subgroups (under 95 years and 95 years or older). The presence, location, and treatment of IPFF, as well as the effect of IPFF on the postoperative weight-bearing status, were compared between groups. A multivariate logistic regression was also performed. A total of 1,669 met the inclusion criteria and were included in the study. Results: The rates of IPFF were significantly higher for patients 95 years or older (p = 0.030). However, fracture location (greater trochanter fractures, p = 0.839; calcar fractures, p = 0.394; and femoral shaft fractures p = 0.110), intraoperative treatment (p = 0.424), and postoperative weight-bearing status (p = 0.229) were similar between the groups. While mortality and nonorthopedicrelated readmissions were significantly higher for patients 95 years or older, orthopedic-related readmissions (p = 0.148) and revisions at the latest follow-up (p = 0.253) were comparable between groups. In a regression analysis, age over 95 years (odds ratio, 2.049; p = 0.049) and body mass index (odds ratio, 0.935; p = 0.016) were independently associated with IPFF. Conclusions The findings of this study suggest that age over 95 years is a significant, independent risk factor for IPFF in patients undergoing cementless HA. Although we were unable to show an impact on perioperative outcomes and orthopedic complications, when operating on patients 95 years or older, surgeons should be aware of the increased risk of IPFF and consider the use of stem designs and fixation types associated with decreased IPFF rates.