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Objectives: Aseptic loosening (AL) is the most common reason of total hip arthroplasty (THA) failure and revision surgery. Osteolysis, caused by wear particles released from implant surfaces, has a vital role in AL. Although previous studies suggest that wear particles always lead to osteoblast programmed death in the process of AL, the specific mechanism remains incompletely understood and osteoblast ferroptosis maybe a new mechanism of AL. Materials and Methods: CoCrMo nanoparticles (CoNPs) were prepared to investigate the influence of ferroptosis in osteoblasts and calvaria resorption animal models. Periprosthetic osteolytic bone tissue was collected from patients who underwent AL after THA to verify osteoblast ferroptosis. Results: Our study demonstrated that CoNPs induced significant ferroptosis in osteoblasts and particles induced osteolysis (PIO) animal models. Blocking ferroptosis with specific inhibitor Ferrostatin‐1 dramatically reduced particle‐induced ferroptosis in vitro. Moreover, in osteoblasts, CoNPs significantly downregulated the expression of Nrf2 (nuclear factor erythroid 2‐related factor 2), a core element in the antioxidant response. The overexpression of Nrf2 by siKeap1 or Nrf2 activator Oltipraz obviously upregulated antioxidant response elements (AREs) and suppressed ferroptosis in osteoblasts. Furthermore, in PIO animal models, the combined utilization of Ferrostatin‐1 and Oltipraz dramatically ameliorated ferroptosis and the severity of osteolysis. Conclusions: These results indicate that CoNPs promote osteoblast ferroptosis by regulating the Nrf2‐ARE signalling pathway, which suggests a new mechanism underlying PIO and represents a potential therapeutic approach for AL. [ABSTRACT FROM AUTHOR]

Objective: To investigate the influence of body mass index (BMI) and hip anatomy on direct anterior approach (DAA) total hip replacement.Subjects and Methods: The study is a retrospective analysis of 124 cases of DAA total hip replacement from 2009 to 2012. The BMI, the ratio of the greater trochanter (GT) and anterior superior iliac spine (ASIS) bilaterally (GT/ASIS), and the vertical distance between the ASIS and GT (AGVD) were obtained from medical records. All cases were categorized into three groups (43, 49, and 32 cases in each group, respectively) based on BMI (BMI <18.5, BMI 18.5-25, and BMI >25) or divided into two groups based on GT/ASIS (≤1.17 or >1.17) or AGVD (≤86 or >86 mm). Operating time, intraoperative bleeding, and surgical complications were compared between different groups.Results: A longer average operating time, more intraoperative bleeding, and a higher rate of complications were observed in the group with the highest BMI. The complications included a case of intraoperative femur fracture, a wound hematoma, and a lateral femoral cutaneous nerve injury. The group with higher GT/ASIS had a shorter average operating time, less bleeding, and a lower complication rate than the group with lower GT/ASIS. Moreover, the group with higher AGVD showed a shorter average operating time, less bleeding, and a lower complication rate compared with the group with lower AGVD.Conclusion: Our study suggests that lower BMI and larger GT/ASIS and AGVD are associated with a shorter operating time, less bleeding, and a lower complication rate in DAA total hip replacement. These findings are valuable for clinicians to make the appropriate choice of surgery types for different individuals. [ABSTRACT FROM AUTHOR]

Background: The coronavirus disease 2019 (COVID-19) rapidly spreads worldwide and causes more suffering. The relation about the aggravation of inguinal pain and COVID-19 was unclear in patients with total hip arthroplasty (THA). This study aimed to evaluate the risk of groin pain aggravation in short-term THA patients after COVID-19. Methods: Between 2020 and 2022, 129 patients with THA who were affected COVID-19 were enrolled. A short-standardized questionnaire was administered during follow-up to inquire about the aggravation of groin ache before and after SARS-COV-2 affection. Furthermore, we evaluated the potential association between the presence of increased pain and various factors, including age, gender, body mass index, diagnosis, and length of hospital stay. Results: The case-crossover study revealed an increased risk of inguinal soreness aggravation when comparing 8 weeks after COVID-19 with 12 weeks before COVID-19 (Relative risk [RR], 9.5; 95% Confidence intervals [CI], 2.259–39.954). For COVID-19 positive patients, multivariate analysis showed length of stay was an independent factor significantly associated with increased risk of aggravation of groin pain (Odds ratio [OR], 1.26; 95%CI, 1.03–1.55, p = 0.027). Conclusion: This study confirms the association between COVID-19 and the exacerbation of soreness in the groin region in THA patients and extended length of stay is a possible contributing factor. This study expands the current literature by investigating the risk of aggravation of inguinal pain in patients with THA after COVID-19, providing valuable insights into postoperative outcomes in this specific population. Trial registration This retrospective study was approved by the Institutional Review Board of Shanghai general hospital (No.2023-264). [ABSTRACT FROM AUTHOR]