Comparison of Clinical Effect of PFNA and Internal Fixation with Anatomical Locking Plate of Proximal Femur in Treatment of Intertrochanteric Fracture of Femur

Purpose:To investigate the clinical value of proximal femoral nail antirotation and anatomical locking plate of proximal femur in the treatment of intertrochanteric fracture of femur.Methods:The study group is treated with PFNA internal fixation.The control group is treated by internal fixation with anatomical locking plate of proximal femur.Results:The time of operation,the amount of intraoperative bleeding and the time of fracture healing in the study group are significantly less than those in the control group.The incidence rate of complication in the study group(3.23%)is significantly lower than that in the control group(17.2%).Data comparison shows P<0.05.Conclusion:The curative effect and prognosis for patients with intertrochanteric fracture of femur treated by PFNA internal fixation are more ideal.

Comparison of Clinical Effect of PFNA and Internal Fixation with Anatomical Locking Plate of Proximal Femur in Treatment of Intertrochanteric Fracture of Femur

Purpose To investigate the clinical value of proximal femoral nail antirotation and anatomical locking plate of proximal femur in the treatment of intertrochanteric fracture of femur.Methods The study group is treated with PFNA internal fixation.The control group is treated by internal fixation with anatomical locking plate of proximal femur.Results The time of operation,the amount of intraoperative bleeding and the time of fracture healing in the study group are significantly less than those in the control group.The incidence rate of complication in the study group(3.23%)is significantly lower than that in the control group(17.2%).Data comparison shows P<0.05.Conclusion The curative effect and prognosis for patients with intertrochanteric fracture of femur treated by PFNA internal fixation are more ideal.

Conversion hip arthroplasty for failed nailing of intertrochanteric fracture: Reflections on some important aspects

In this editorial,I present my comments on the article by Solarino et al.Conversion hip arthroplasty,which is an optional salvage procedure performed following unsuccessful fixation of intertrochanteric femur fractures in elderly pati-ents,entails more complex processes and higher rates of operative complications than primary arthroplasty.Hence,it is important to consider the appropriateness of the primary treatment choice,as well as the adequacy of nailing fixation for intertrochanteric fractures.This article briefly analyzes the possible factors contributing to the nailing failure of intertrochanteric fractures and attempts to find corresponding countermeasures to prevent fixation failures.It also analyzes the choice of treatment between nailing fixation and primary arthroplasty for intertrochanteric fractures.

PFNA2 versus 95 Degree Condylar Blade Plate in the Management of Unstable Trochanteric Fractures

Purpose: The proximal femoral nail anti-rotation (PFNA) is known to have advantages in enhancing the anchorage ability of internal fixation in elderly unstable osteoporotic intertrochanteric fracture patients. However whether it is superior to condylar blade fixation is not clear. This study aimed to determine which treatment has better clinical outcomes in older patients. Materials and Methods: A total of 86 patients over the age of 60 with unstable trochanteric fractures within the past 3 weeks, were included in this prospective study conducted from June 1, 2018, to May 31, 2021. All the intertrochanteric fractures were classified according to AO/OTA classification. Among them, 44 cases were treated with the Proximal Femoral Nail (PFNA2) with or without an augmentation screw, and 42 cases were treated with the Condylar Blade Plate. In addition, the operative time, intraoperative blood loss, intraoperative and postoperative blood transfusion, postoperative weight-bearing time, hospitalization time, Harris score of hip function, Kyle’s criteria and postoperative complications were compared between the two groups. Results: The mean duration of surgery for the PFN group was 66.8 minutes (on average), whereas for the condylar blade plate group, it was 99.30 minutes (on average). The PFNA2 group experienced less blood loss (average of 80 mL) compared to the condylar blade plate group (average of 120 mL). Union and partial weight-bearing occurred earlier in the PFNA2 group (14.1 weeks and 10.6 weeks, respectively) compared to the Condylar blade plate group (18.7 weeks and 15.8 weeks). In two patients from the PFNA2 group, screw backing out and varus collapse complications were encountered;however, these patients remained asymptomatic and did not require revision surgery. In two other patients, screw cut out and breakage of the nail at the helical screw hole leading to non-union of the proximal femur were observed during the nine-month follow-up, necessitating revision surgery with prosthetic replacement. Among the condylar blade plate group, three patients experienced complications, including blade breakage at the blade and plate junction. In two cases, the fracture united in varus, and in one case, the blade cut through, resulting in non-union of the femoral head, which required revision surgery. According to the Harris hip score and Kyle’s criteria, a good-excellent outcome was observed in 92.85% of cases in the PFNA2 group and 90.90% of cases in the condylar blade plate group. Conclusion: Both the Proximal Femoral Nail A2 and Condylar blade plate are effective implants for the treatment of unstable trochanteric fractures. The intramedullary implant promotes biological healing and allows for early ambulation with minimal complications. Similarly satisfactory restoration of anatomy and favorable radiological and functional results can be achieved with the biological fixation provided by the 95-degree condylar blade plate. However, the use of PFNA2 internal fixation technique has the advantage of less trauma in elderly patients than the 95-degree condylar blade plate.

Risk Assessment of Retrograde Intramedullary Nailing for Proximal Humeral Fracture

In proximal humeral fracture except AO classification 11A1, fixations with a locking plate and nails are recommended. We performed mechanical tests to investigate whether retrograde intramedullary nailing has fixation stability comparable to those of anterograde intramedullary nailing and locking plate which achieve clinically favorable outcomes. In retrograde intramedullary nailing, a nail entry point is made in the diaphysis, for which reduction of stiffness of the humerus is of concern. Thus, we investigated the influence of a nail entry point made in the diaphysis on humeral strength. Retrograde intramedullary nailing had fixation stability against bending and a force loaded in the rotation direction comparable to those of anterograde intramedullary nail and locking plate. Displacement by the main external force loaded on the humerus, compressive load, was less than half in the bone fixed by retrograde intramedullary nailing compared with that in the bone fixed with a locking plate, showing favorable fixation stability. It was clarified that stiffness of the humerus against rotation and a load in the compression direction is not reduced by a nail entry point made by retrograde intramedullary nailing.

Fragility of statistically significant findings from randomized clinical trials of surgical treatment of humeral shaft fractures:A systematic review

BACKGROUND Despite recent meta-analyses of randomized controlled trials(RCTs),there remains no consensus regarding the preferred surgical treatment for humeral shaft fractures.The fragility index(FI)is an emerging tool used to evaluate the robustness of RCTs by quantifying the number of participants in a study group that would need to switch outcomes in order to reverse the study conclusions.AIM To investigate the fragility index of randomized control trials assessing outcomes of operative fixation in proximal humerus fractures.METHODS We completed a systematic review of RCTs evaluating the surgical treatment of humeral shaft fractures.Inclusion criteria included:articles published in English;patients randomized and allotted in 1:1 ratio to 2 parallel arms;and dichotomous outcome variables.The FI was calculated for total complications,each complication individually,and secondary surgeries using the Fisher exact test,as previously published.RESULTS Fifteen RCTs were included in the analysis comparing open reduction plate osteosynthesis with dynamic compression plate or locking compression plate,intramedullary nail,and minimally invasive plate osteosynthesis.The median FI was 0 for all parameters analyzed.Regarding individual outcomes,the FI was 0 for 81/91(89%)of outcomes.The FI exceeded the number lost to follow up in only 2/91(2%)outcomes.CONCLUSION The FI shows that data from RCTs regarding operative treatment of humeral shaft fractures are fragile and does not demonstrate superiority of any particular surgical technique.

Proximal Femur Bionic Nail (PFBN): A Panacea for Unstable Intertrochanteric Femur Fracture

With the aging population,intertrochanteric femur fracture in the elderly has become one of the most serious public health issues and a hot topic of research in trauma orthopedics.Due to the limitations of internal fixation techniques and the insufficient mechanical design of nails,the occurrence of complications delays patient recovery after surgical treatment.Design of a proximal femur bionic nail(PFBN)based on Zhang’s N triangle theory provides triangular supporting fixation,which dramatically decreases the occurrence of complications and has been widely used for clinical treatment of unstable intertrochanteric femur fracture worldwide.In this work,we developed an equivalent biomechanical model to analyze improvement in bone remodeling of unstable intertrochanteric femur fracture through PFBN use.The results show that compared with proximal femoral nail antirotation(PFNA)and InterTan,PFBN can dramatically decrease the maximum strain in the proximal femur.Based on Frost’s mechanostat theory,the local mechanical environment in the proximal femur can be regulated into the medium overload region by using a PFBN,which may render the proximal femur in a state of physiological overload,favoring post-operative recovery of intertrochanteric femur fracture in the elderly.This work shows that PFBN may constitute a panacea for unstable intertrochanteric femur fracture and provides insights into improving methods of internal fixation.

构建股骨转子间骨折股骨近端防旋髓内钉内固定失效的风险预测模型

背景:股骨转子间骨折是主要的老年脆性骨折类型,股骨近端防旋髓内钉是首选手术方案,但术后内固定失效的相关因素尚存在争议。目的:通过术前评估患者影像学资料提出一种新的股骨转子间骨折“三柱”分类法,并分析其与术后内固定失效的交互关系,利用数字技术运算开发和验证风险预测模型,便于临床医生术前甄别并干预高风险患者。方法:选择2012年6月和2022年6月佛山市中医院三水医院收治的股骨转子间骨折患者,按照术后是否出现内固定失效结局,分为内固定失效组和内固定维持组。根据患者术前X射线片将股骨近端分为“三柱”:内侧柱、外侧柱及中柱,每柱均有不同的亚组分型。分析“三柱”的形态特征与股骨近端防旋髓内钉内固定术后复位失效的关系,通过先单因素后多因素logistics回归分析,筛选出引起内固定失效的独立风险因素,根据独立风险因素利用R语言软件构建风险预测模型。采用自助法重抽样1000次,使用受试者工作特征曲线下的面积、校准曲线、临床决策曲线评价模型的区分度、校准能力及临床应用价值。通过Youden指数确定预测模型的最佳风险分界值,据此将患者分为高、低风险组,根据模型风险预测能力的准确度来评价其稳定性和外延性。结果与结论:①利用“三柱”分型系统预测骨折术后内固定失效的4个独立风险因素,分别为内侧柱(小转子及股骨距粉碎性骨折)[优势比=5.385,95%CI(1.961,14.782),P=0.001]、中间柱(烟囱型)[优势比=2.893,95%CI(1.167,7.173),P=0.022]、外侧柱(外侧壁厚度<20.5 mm)[优势比=2.804,95%CI(1.078,7.297),P=0.035]及外侧柱(外侧壁骨折)[优势比=4.278,95%CI(1.670,10.959),P=0.012];②构建的风险预测模型表现出良好的区分度和准确度[受试者工作特征曲线下面积=0.852,95%CI(0.837,0.922)],校准曲线显示模型预测风险和实际发生风险有较好的一致性;③临床决策曲线提示风险阈值概率在0.2-0.82范围内时,模型具有较好的临床适用性;风险概率为28%是模型风险分层的最佳阈值,模型在不同风险组别患者的预测性能较好;④此次研究通过“三柱”分型系统构建预测模型计算股骨转子间骨折患者术后内固定失效的风险概率,此方法准确、简便,易于临床应用,可作为一种数字化工具指导临床个性化治疗。

Biomechanical analysis of the computer-assisted internal fixation of a femoral neck fracture

The number and spatial configuration of the screws will affect the stability and prognosis of the fractures.In our study,we assessed the biomechanical effects of the double-head cannulated compression screw(DhCCS)and ordinary cannulated compression screw(OCCS)for the treatment of femoral neck fractures by using computer finite element analysis.The original digital imaging and communications in medicine(DICOM)data of a proximal femur were imported into Materialise’s interactive medical image control system(MIMICS)software for modeling.Both DhCCS and OCCS 3D-models were obtained by using the 3D scan technique.Using the fracture model and internal fixation assembly model with an inverted triangle,two horizontal and vertical distribution were established in UG software.Next,the displacement and stress distribution were calculated in ANSYS software.The displacement value of the femoral head in the DhCCS group was smaller than that in the OCCS group,and the displacement value in the two horizontal groups was smaller than that in the vertical group.The stress distribution in the DhCCS group was concentrated on the screw rod at the fracture block and thread end,while only at the fracture block in the OCCS group.The stress in the horizontal group was more dispersed on the screws than that in the vertical group.DhCCS has reliable stability for the fixation of femoral neck fractures and applied in the clinical work and 2 horizontal fixation can be used when two screws are selected.

三种内固定方法治疗Pauwels Ⅲ型股骨颈骨折伴前内侧骨缺损的有限元分析

背景:不稳定型股骨颈骨折伴前内侧骨缺损是非常少见且难以处理的,治疗此种骨折的最佳内固定方案一直是骨科医生中持续争论的话题。目的:通过有限元分析评估不同内固定方式治疗Pauwels Ⅲ型股骨颈骨折伴前内侧缺损的生物力学性能,以期为临床手术决策提供实验支撑。方法:利用Mimics 21.0、Geomagic和Solidworks软件构建伴有前内侧缺损且Pauwels角为70°的股骨颈骨折模型,模拟3种内固定方法:A组(3枚空心钉+内侧钢板)、B组(股骨颈动力交叉钉+1枚空心钉)和C组(4枚空心钉“菱形固定”)。在3倍体质量2100 N的载荷下分析3组模型股骨、内固定以及股骨头的应力和位移变化。结果与结论:①A组模型的股骨整体应力最小,且受力更加均匀且分散;B组内固定模型的应力较小,说明其具有更好的应力分散和抗剪切的作用;A组股骨应力侧的应力明显小于其余两组,且未发生应力集中现象;②A组无论是整体股骨模型、内固定或是股骨头的位移均小于其余两组,说明空心钉联合内侧钢板能够起到更好的稳定作用,可减少髋内翻的发生;③3枚螺钉联合内侧支撑钢板应用于垂直、不稳定且前内侧骨缺损的股骨颈骨折,可显著提高骨折的稳定性,提高对变形力的抵抗力,是治疗该类型骨折的不错选择。

不同载荷条件下三种内固定方式治疗PauwelsⅢ型股骨颈骨折的有限元分析

背景:治疗PauwelsⅢ型股骨颈骨折的最佳内固定方式仍未达成共识,既往相关有限元分析大多采用单一简化载荷条件,对于常用内固定装置的生物力学特性还需进一步探究。目的:通过有限元方法分析空心加压螺钉、动力髋螺钉和股骨颈系统治疗PauwelsⅢ型股骨颈骨折在单腿站立载荷及侧方跌倒载荷条件下的生物力学特性。方法:通过CT扫描获取健康成人股骨DICOM数据,导入Mimics 15.0软件,得到骨组织的粗糙模型,再通过Geomagics软件对Mimics导出的数据进行优化处理,然后根据空心加压螺钉、动力髋螺钉和股骨颈系统的临床应用参数采用Pro/E软件建立3种内固定模型并与股骨模型组装,最后导入Ansys软件进行加载、计算,分析3种内固定模型在单腿站立载荷及侧方跌倒载荷的不同工况下股骨和内固定的应力分布和位移情况,以及股骨距和Ward三角区的应力特点。结果与结论:(1)单腿站立载荷及侧方跌倒载荷下,3种内固定模型的股骨近端应力均主要分布在股骨颈骨折端内上方,3种内固定模型的股骨近端、骨折端、Ward三角以及股骨距的应力峰值均为股骨颈系统内固定模型最小,空心加压螺钉内固定模型最大;(2)单腿站立载荷及侧方跌倒载荷下,3种内固定模型的股骨近端位移峰值均位于股骨头顶端,且位移峰值均为股骨颈系统内固定模型最小,空心加压螺钉内固定模型最大;(3)3种内固定模型在单腿站立及侧方跌倒载荷条件下内固定的位移峰值均位于内固定装置上方顶端,且位移峰值均为股骨颈系统内固定模型最小,空心加压螺钉内固定模型最大;(4)3种内固定模型在单腿站立及侧方跌倒载荷条件下内固定的应力均主要集中在内固定装置的骨折端附近区域,且内固定应力峰值均为股骨颈系统内固定模型最小,空心加压螺钉内固定模型最大;(5)结果表明,股骨颈系统的机械稳定性最佳,但是可能存在对于骨折端和股骨距应力遮挡的风险;股骨颈系统的内固定装置应力更为分散,内固定断裂风险更低。

空心双头加压螺钉治疗Hoffa骨折的临床研究

【目的】回顾性分析空心双头加压螺钉在Hoffa骨折中应用的临床效果。【方法】本院自2004至2013年间治疗的Hoffa骨折患者共21例，其中男13例，女8例；车祸伤15例，高处坠落伤4例，砸伤2例；按Letenneur分型I型11例，Ⅱ型6例，Ⅲ型4例；闭合性骨折15例，开放性骨折6例；全部患者均采用空心双头加压螺钉进行骨折固定，术后及时进行康复功能锻炼。【结论】术后随访时间6个月至3年，平均21．5个月；随访结果为所有骨折均达到骨性愈合，术中术后无血管及神经损伤、术后没有出现伤口及关节腔感染、术后无螺钉松动及断裂等并发症发生；根据Letenneur评估系统进行术后功能评估，本组患者优良18例，可2例，差1例，优良率85．7％。【结论】空心双头加压螺钉固定治疗Hoffa骨折具有手术创伤小、固定可靠、术后功能恢复好的优点，是一种疗效可靠的治疗方法。

改良跗骨窦锁定钢板联合经皮空心钉内固定对跟骨骨折患者AOFAS评分及并发症的影响

目的探讨跟骨骨折患者联合应用改良跗骨窦锁定钢板及经皮空心钉内固定治疗对美国足踝学会踝与后足功能(AOFAS)评分及并发症的影响。方法选择2018年1月至2019年1月某院收治的72例跟骨骨折患者,按随机数表法分为两组,各36例。对照组行传统外侧L形切口复位内固定,观察组行改良跗骨窦锁定钢板联合经皮空心钉内固定,比较两组跟骨高度、Gissane角、Bohler角、AOFAS评分及并发症。结果治疗6个月后,观察组跟骨高度、Gissane角、Bohler角、AOFAS评分为(42.64±1.91)mm、(113.42±6.28)°、(32.56±1.10)°、(92.08±4.59)分,对照组为(39.42±1.13)mm、(118.89±6.32)°、(28.08±2.43)°、(87.31±5.87)分,差异有统计学意义(P<0.05);观察组并发症发生率2.78%,低于对照组的22.22%,差异有统计学意义(P<0.05)。结论跟骨骨折患者联合应用改良跗骨窦锁定钢板及经皮空心钉内固定治疗,可有效提高AOFAS评分,改善足部功能,且并发症较少,利于患者转归。

Comparison of two kinds of intramedullary nails in the treatment of femoral shaft fractures in adults

Intramedullary nails have been widely used in treating femoral shaft fractures. However, end caps falling into soft tissue intraoperatively may cause trouble to surgeons, prolong operative time and increase radiation exposure. Additionally, difficulties may be encountered when removing nails because of callus formation over the nail tip. We performed a prospective study to compare two types of nails in managing femoral shaft fractures. Methods Group I consisted of seventy-four patients with unilateral femoral shaft fractures treated with cannulated interlocking anatomical femoral intramedullary nails. Group II consisted of seventy-eight patients treated with cannulated interlocking anatomical femoral intramedullary nails with tail wires. The patients＇ ages, fracture severity, duration of operation, fluoroscopy time, blood loss and falls of end caps into soft tissue were recorded. Nails were removed after fracture healing. The duration of operation and blood loss during nail removal were recorded. Results There were no significant differences between groups with respect to age and fracture severity （P 〉0.05）. End caps fell into soft tissue 17 times in 15 cases in group I and 21 times in 16 cases in group I1. An average of seven minutes was spent recovering a lost cap in group I. In group II, all lost caps were recovered immediately. The duration of operation and fluoroscopy time in group II was significantly less than in group I （P 〈0.05）. Asymptomatic palpable nodules were detected in 4 cases in group I1. Nail removals were performed on 58 patients in group I and 69 patients in group I1. The duration of operation, blood loss and complications in group II were less than in group I （P〈0.05）. Conclusion Intramedullary nails with tail wires facilitate both fracture fixation and nail removal, which can be used to treat femoral shaft fractures with less radiation exposure, shorter surgical time and fewer complications.

Hoffa骨折切开复位内固定术中不等距无头加压螺纹钉的可行性

目的：对Hoffa骨折切开复位内固定术中不等距无头加压螺纹钉的可行性进行分析与探讨。方法：选取2009年12月-2011年12月在本院接受治疗的Hoffa骨折患者50例,其中22例外髁骨折,12例内髁骨折,16例双髁骨折,随机分为观察组与对照组,每组各25例。观察患者实施不等距无头加压螺纹钉切开复位内固定术治疗,完成手术后的第2天为患者拔管,并指导患者展开被动与主动活动锻炼,完成手术后2个月,鼓励患者行负重行走训练。对照组患者单纯行复位内固定手术治疗,比较两组患者治疗效果。结果：对所有患者进行2~24个月的随访调查发现,观察组所有患者骨折部位均出现骨性愈合,对照组6例患者骨性愈合,两组比较差异有统计学意义（P〈0.05）。采用Letenneur法对患者功能恢复情况实施评估,观察组22例优良,3例为可,无患者出现内固定松动、深部感染以及关节僵直等情况。对照组14例为优良,2例为可,9例为差,其中6例患者出现内固定松动,2例患者关节僵硬,1例患者发生深部感染,观察组治疗有效率明显优于对照组,两组比较差异有统计学意义（P〈0.05）。结论：不等距无头加压螺纹钉具有较强的把持力,而且无头结构在股骨髁部骨折中比较适用,能够达到患者骨折端解剖复位,内固定比较稳定,再加上患者早期进行功能性锻炼,因此能够取得较为理想的临床效果,值得临床应用与推广。

交锁髓内钉内固定术对胫骨远端关节外骨折患者HSS、AOFAS评分的影响

目的探究交锁髓内钉(IMN)内固定术对胫骨远端关节外骨折患者美国特种外科医院(HSS)评分、美国足踝外科医生协会评分系统(AOFAS)评分的影响。方法选择2018年1月至2021年1月于我院就诊的100例胫骨远端关节外骨折患者作为研究对象,按照治疗方案差异性将其分为对照组与观察组,每组50例。对照组给予微创经皮钢板固定术(MIPPO)治疗,观察组给予IMN内固定术治疗。比较两组的治疗效果。结果两组的手术时间、愈合时间、住院时间以及术中出血量无显著差异(P>0.05)。观察组的术前等待时间、下地负重时间明显短于对照组(P<0.05)。治疗6个月后,两组的踝关节背屈度数、胫骨对线度数无显著差异(P>0.05)。两组的并发症总发生率无显著差异(P>0.05)。治疗1个月后,观察组的HSS、AOFAS评分高于对照组(P<0.05)。结论IMN内固定术有利于促进胫骨远端关节外骨折患者短期膝、踝关节功能恢复,可缩短患者术前等待时间以及术后下地负重时间,降低并发症发生风险,安全性尚可。

股骨颈骨折空心钉内固定后股骨近端骨质疏松的有限元分析

背景:股骨颈骨折空心钉内固定术后由于患肢短期内常常不能负重,且高刚度的内植物对骨折断端存在应力遮挡效应,易导致患肢出现骨质疏松,股骨近端生物力学分布发生变化,术后股骨头坏死发病率较高,目前关于股骨颈骨折术后股骨近端骨质疏松对股骨近端及空心钉生物力学影响的研究较少。目的:通过有限元分析探讨股骨颈骨折术后发生骨质疏松对空心钉内固定治疗的生物力学影响,探究生物力学因素在股骨头坏死进程中的作用。方法:获取1例股骨颈骨折患者股骨CT扫描数据,利用Mimics 19.0、3-Matic、UG 11.0、Hypermesh 14.0、Abaqus软件建立空心钉治疗股骨颈骨折的股骨近端模型,利用Abaqus软件分析1种术后股骨近端无骨质疏松、3种术后股骨近端骨质疏松的有限元模型,测量分析4种模型不同部件的应力、接触压力、位移峰值及云图,对比分析股骨头内部应力变化及分布情况。结果与结论:股骨头及下前空心钉的应力、接触压力随骨质疏松程度变化较大,4种模型的位移峰值随着骨质疏松程度加重而缓慢增长。通过单因素方差分析,结果显示骨质疏松程度对不同部件的应力、接触压力、位移峰值无显著性影响,股骨头内部应力分布随骨质疏松发生相应变化,股骨近端的生物力学环境变化对股骨头坏死有着重要影响。

Compression Test and Finite Element Analysis for Failure Criterion of the Tibial Post of a Posterior-Stabilized Knee Prosthesis

Post cam mechanism of Posterior Stabilized (PS) knee prostheses is useful to realize intrinsic stability for cases with severe degeneration. However, some retrieval studies report severe failure of the polyethylene tibial post. We thought that severe failures were caused by high loads during daily activities. In the current study, we performed a compression test and a finite element analysis of the mechanical forces produced in the tibial post in posterior-stabilized knee prostheses in order to develop a specification for the tibial posts found in the polyethylene inserts of PS knee prostheses. Anterior tibial post impingement and posterior tibial post impingement were simulated. The surface pressure values detected in the compression test were consistent with those obtained in the FE analysis. Of the three designs, the lowest von Mises stress values were generated inside the round tibial post;therefore, tibial posts should be round. The risk of tibial post failure was low when 500 or 1000 N was loaded onto the knee joint. It was suggested that tibial post failure occurs when the shear strain at the base of the tibial post exceeds 0.1.

髋关节囊周围神经阻滞与髂筋膜间隙阻滞对老年股骨粗隆间骨折患者镇痛效果的对比研究

目的 探讨髋关节囊周围神经(pericapsular nerve group, PENG)阻滞与髂筋膜间隙阻滞(fascia iliaca compartment block, FICB)对老年股骨粗隆间骨折(intertrochanteric femur fracture, IFF)患者股骨近端防旋髓内钉(proximal femoral nail anti-rotation, PFNA)内固定术的镇痛效果。方法 选取2022年1—12月首都医科大学附属北京积水潭医院老年IFF患者60例,随机分为P组和F组,每组各30例。P组采用PENG阻滞,F组采用FICB。两组患者均接受椎管内麻醉进行手术,术后均给予患者静脉自控镇痛(patient controlled intravenous analgesia, PCIA)。比较两组患者不同时点(T1,神经阻滞前;T2,神经阻滞后30 min;T3,术后6 h;T4,术后24 h;T5,术后48 h)静息和运动时的视觉模拟评分(visual analogue score, VAS)、术后补救镇痛率、镇痛满意度评分、住院时间、PCIA按压次数及不良反应发生率。结果 60例患者中,男23例,女37例,年龄65~85岁,平均(70.6±6.0)岁。两组T2~T5时点静息和运动时VAS均低于T1时点,差异均有统计学意义(P <0.05);两组静息和运动时所有时点VAS、术后补救镇痛率、镇痛满意度评分、住院时间、PCIA按压次数及不良反应发生率的比较,差异均无统计学意义(P>0.05)。结论 PENG阻滞与FICB均可缓解老年IFF患者PFNA内固定术的镇痛,且镇痛效果相当。

Haraguchi Ⅱ型后踝骨折3种内固定方式的有限元分析

目的 基于计算机三维有限元技术方法研究HaraguchiⅡ型后踝骨折不同内固定材料的生物力学特性,确定后踝骨折的最佳内固定材料,为临床提供基础理论支持。方法 通过计算机三维有限元技术,建立后踝空心螺钉固定+内踝空心螺钉(A组)、后踝支撑钢板固定+内踝空心螺钉(B组)和后踝重建钢板固定+内踝空心螺钉(C组)三种不同内固定材料固定HaraguchiⅡ型后踝骨折的三维有限元模型,并对模型行生物力学分析,比较各组内固定材料的优劣性。结果 两组钢板固定模型的最大主应力和胫骨应力要明显低于3枚空心螺钉固定模型组,而重建钢板组的应力又低于支撑钢板组;三组模型中内踝处空心螺钉的应力重建钢板组最小,空心螺钉组最大;胫骨的总位移变化范围空心螺钉组最大,支撑钢板组次之,重建钢板组最小。结论 重建钢板固定HaraguchiⅡ型后踝骨折的生物力学稳定性最强,为一种比较理想的固定方法,对临床具有一定的指导性。