ABSTRACT
Objective: To study the specific alignment and structure of cancellous bone within the talus in order to understand the mechanism of force transmission within the bone and to provide some theoretical basis for the repositioning of talar fractures and the design of prostheses. Methods: In January 2020, a total of 40 adult talar bone specimens were scanned by Micro-CT in 20 pairs obtained from the Department of Orthopedics of Tianjin Hospital. The bone volume fraction, bone surface area fraction, trabecular thickness, number of trabeculae, trabecular pattern factor of the head, neck and body of the talus were calculated, and the differences in each parameter were compared between different parts of the same side and different sides of the same part, respectively. The talus was cut into 2 mm thick slices in the coronal, sagittal and horizontal planes using a hard tissue slicer, and the slices were then scanned using high-resolution X-rays to describe the bone structure. Results: There were no statistically significant differences between the medial and lateral talar and right and left side in lateral trabecular bone volume fraction, bone surface area fraction, trabecular thickness, trabecular number, trabecular pattern factors (all P>0.05). The number of trabeculae in the talar head, neck and body was 1.608±0.150, 1.639±0.142 and 1.749±0.159, respectively; trabecular thickness (µm) in the talar head, neck and body was 0.378±0.054, 0.370±0.053 and 0.331±0.062, respectively; and the trabecular pattern factors (mm-1) in the talar head, neck and body was -0.407±0.699, -0.478±0.848 and -1.029±0.851, respectively. There were significant differences between talar head, neck and the talar body trabeculae in terms of the number of trabeculae, trabecular thickness,trabecular pattern factor parameters(all P<0.05). The structure of the talar body trabeculae was found to consist of plate trabeculae arranged vertically parallel to each other in the coronal, sagittal and horizontal planes. The talar neck trabeculae were twisted, external-superior to internal-inferior reticular plate structure that travelled posteriorly and anteriorly, and the talar head trabeculae consisted of similarly parallel aligned semi-arc-shaped external-superior and internal-inferior trabeculae. Conclusion: The talar trabeculae are clearly directional and functional, so anatomical reduction should be achieved after the fracture; at the same time, the design of the talar prosthesis should take into account the stress distribution and direction of the prosthesis during walking and standing.
Subject(s)
Talus , Ankle Joint , Radiography , Talus/diagnostic imaging , X-Ray Microtomography , X-RaysABSTRACT
BACKGROUND: The ultrasound-guided interscalene block (ISB) has been considered a standard technique in managing pain after shoulder surgery. However, this method was associated with the incidence of hemi-diaphragmatic paresis. In contrast to ISB, supraclavicular block (SCB) was suggested to provide effective anaesthesia for shoulder surgery with a low rate of side-effects. Thus, we performed a meta-analysis of randomised controlled trials (RCTs) to compare SCB with ISB for evaluating the efficacy and safety. METHOD: The literature was searched from PubMed, Wiley Online Library, EMBASE, and the Cochrane Library by two reviewers up to April 2017. All available RCTs written in English that met the criteria were included. Two authors pulled data from relevant articles and assessed the quality with the Cochrane Handbook. Review Manager 5.3 software was used to analyse the data. RESULTS: Five RCTs and one prospective clinical study met the eligibility criteria and were included in the meta-analysis. We considered that there were no statistically significant differences between supraclavicular and interscalene groups in procedural time (P = 0.81), rescue analgesia (P = 0.53), and dyspnoea (P = 0.6). The incidence of hoarseness and Horner syndrome was statistically lower in the SCB group than in the ISB group (P = 0.0002 and P < 0.00001, respectively). CONCLUSION: The meta-analysis showed that ultrasound-guided SCB could become a feasible alternative technique to the ISB in shoulder surgery.
