Objective: Discrepancies in the definition of adductor canal block (ACB) lead to inconsistent results. To investigate the actual analgesic and motor-sparing effects of ACB by anatomically defining femoral triangle block (FTB), proximal ACB (p-ACB), and distal ACB (d-ACB), we re-classified the previously claimed ACB approaches according to the ultrasound findings or descriptions in the corresponding published articles. A meta-analysis with subsequent subgroup analyses based on these corrected results was performed to examine the true impact of ACB on its analgesic effect and motor function (quadriceps muscle strength or mobilization ability). An optimal ACB technique was also suggested based on an updated review of evidence and ultrasound anatomy. Materials and Methods: We systematically searched studies describing the use of ACB for knee surgery. Cochrane Library, PubMed, Web of Science, and Embase were searched with the exclusion of non-English articles from inception to 28 February 2022. The motor-sparing and analgesic aspects in true ACB were evaluated using meta-analyses with subsequent subgroup analyses according to the corrected classification system. Results: The meta-analysis includes 19 randomized controlled trials. Compared with the femoral nerve block group, the quadriceps muscle strength (standardized mean difference (SMD) = 0.33, 95%-CI [0.01; 0.65]) and mobilization ability (SMD = −22.44, 95%-CI [−35.37; −9.51]) are more preserved in the mixed ACB group at 24 h after knee surgery. Compared with the true ACB group, the FTB group (SMD = 5.59, 95%-CI [3.44; 8.46]) has a significantly decreased mobilization ability at 24 h after knee surgery. Conclusion: By using the corrected classification system, we proved the motor-sparing effect of true ACB compared to FTB. According to the updated ultrasound anatomy, we suggested proximal ACB to be the analgesic technique of choice for knee surgery. Although a single-shot ACB is limited in duration, it remains the candidate of the analgesic standard for knee surgery on postoperative day 1 or 2 because it induces analgesia with less motor involvement in the era of multimodal analgesia. Furthermore, data from the corrected classification system may provide the basis for future research.

Whether the use of neuraxial anesthesia or general anesthesia leads to more favorable postoperative outcomes in patients receiving hip fracture surgery remains unclear. We used data from the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) Data Files between 2016 and 2020 to investigate the association of neuraxial anesthesia and general anesthesia with morbidity and mortality after hip fracture surgery. Inverse probability of treatment weighting (IPTW) was used to balance the baseline characteristics, and multivariable Cox regression models were used to estimate the hazard ratio (HR) with a 95% confidence interval (CI) for postoperative morbidity and mortality among the different anesthesia groups. A total of 45,874 patients were included in this study. Postoperative adverse events occurred in 1087 of 9864 patients (11.0%) who received neuraxial anesthesia and in 4635 of 36,010 patients (12.9%) who received general anesthesia. After adjustment for IPTW, the multivariable Cox regressions revealed that general anesthesia was associated with increased risks of postoperative morbidity (adjusted HR, 1.19; 95% CI, 1.14–1.24) and mortality (adjusted HR, 1.09; 95% CI, 1.03–1.16). The results of the present study suggest that, compared with general anesthesia, neuraxial anesthesia is associated with lower risks of postoperative adverse events in patients undergoing hip fracture surgery.

This paper introduces a wearable, cuffless blood pressure (BP) monitoring system for continuous, real-time measurement in the operating room. Traditional cuff-based BP monitoring is intermittent and unsuitable for surgery, while intra-arterial measurements are invasive. The system uses a finger clip with a force sensor to detect pressure changes caused by arterial pulsations, with a waveform decomposition analysis algorithm estimating systolic and diastolic BP in real time. A clinical validation study involving 46 patients in the operating room demonstrated the system’s accuracy, with reference measurements from an intra-arterial catheter. The reference systolic pressure ranged from 83 mmHg to 194 mmHg, and diastolic pressure from 42 mmHg to 105 mmHg. The error between paired measurements was − 1.44 ± 6.64 mmHg for systolic and 3.35 ± 6.91 mmHg for diastolic, with the device’s measurements meeting the ISO 81060-2:2018 accuracy specification of 5 ± 8 mmHg. Pearson correlation coefficients were r = 0.90 (p < 0.01) for systolic and r = 0.78 (p < 0.01) for diastolic, indicating significant correlations with intra-arterial catheter measurements. The data analysis also considered the IEEE 1708 standard, ensuring compliance with guidelines for non-invasive BP monitoring. In collaboration with the device developer, the authors designed the clinical calibration protocol and user interface to ensure compatibility with intra-operative monitoring workflows. This study represents the first clinical validation of a tactile force–sensing cuffless system against intra-arterial reference measurements, demonstrating its feasibility for real-time, non-invasive blood pressure monitoring during anesthesia.