Three-dimensional finite element analysis of intramedullary nail with different materials in the treatment of intertrochanteric fractures

Intramedullary nails are the common treatment options for femoral intertrochanteric fractures. However, aseptic loosening is considered to be one of the primary forms of failure that can be caused by the stress shielding between the bone and implants. The matching in mechanical properties of implant and bone is a key issue to prevent this failure. Polyetheretherketone (PEEK) and Function-graded (FG) materials are widely used in clinical because of their excellent mechanical properties. In this study, to investigate the biomechanical behaviors of intramedullary nails made of Ti-6Al-4V alloy, Stainless Steel (SS), PEEK and two FG materials, three-dimensional finite element models of intertrochanteric fracture femur with intramedullary nail were constructed with ABAQUS. The maximum von Mises stress on the femoral fracture surface fixed by PEEK intramedullary nail was the largest, followed by FG intramedullary nail, which help stimulate bone growth and subsequently reduce fracture healing time. Compared with traditional metal intramedullary nails, PEEK and FG implants might increase von Mises stress along the same path in the proximal femur. The results showed that PEEK and FG intramedullary nails obviously changed the stress distributions in the bone and reduced stress shielding. This finding indicated that PEEK and FG intramedullary nails have the potential to become alternatives to the conventional metal intramedullary nails.     

A randomized controlled trial: Comparison of one-per-mil tumescent technique and tourniquet in surgery for burn hand contracture in creating clear operative field and assessment of functional outcome

BackgroundThis study aims to compare the use of one-per-mil tumescent solution (a mixture of epinephrine and 0.2% lidocaine in a ratio of 1:1,000,000 in normal saline solution) and tourniquet to create clear operative fields and to evaluate the functional outcomes after post burn hand contracture surgery.MethodsThe subjects of this randomized controlled trial were divided into one-permil tumescent technique and tourniquet group for a similar surgical procedure. Three independent assessors evaluated the clarity of the operative fields through recorded videos for the first 15 min and the first 10-minute of each hour of the surgery. Functional outcome was evaluated at least three months postoperatively using total active and passive motion (TAM and TPM) of each digit. Malondialdehyde (MDA) and tumor necrosis factor alpha (TNF-α) were tested during baseline (5 min before the procedures), ischemia phase, and reperfusion phase (a phase when the blood flow returned to the tissue).Results35 subjects were included in this study: 17 in the tumescent group and 18 in the tourniquet group. We found a significant difference in the clarity of operative field between tumescent and tourniquet groups, 5 vs 35 bloodless operative fields, respectively (p < 0.05). TAM and TPM of each digit before surgery and 3 months postoperatively showed no significant difference between both groups (p > 0.05). Furthermore, we found no difference in MDA and TNF-α levels between both groups at their respective phases.ConclusionsThe use of one-per-mil tumescent technique does not replace tourniquet use to create bloodless operative fields in burned hand contracture surgery. However, the postoperative functional results were similar in both groups showing that tumescent technique can be used as an alternative to tourniquet without compromising outcomes. The MDA and TNF-α examinations do not provide conclusive outcomes regarding ischemia and reperfusion injury.     

幼龄大鼠颅骨缺损及钛网修补后对其颅骨生长和智力发育的影响

目的:针对目前小儿颅骨缺损的多种治疗观念及课题组前期研究提出的“滑行理论”,利用幼龄SD大鼠模型探究颅骨缺损及钛网修补后对其颅骨生长和智力发育的影响。方法:将3周幼龄SD大鼠随机分成假手术对照组(SOC)、颅骨缺损组(SD)和钛网修补组(TMR),术前排除组间差异,术后同环境下饲养至性成熟进行旷场实验和Morris水迷宫实验后处死,测量体质量、颅骨径线、颅骨厚度、缺损内径和脑容积等指标。结果:术前体质量及颅骨径线显示三组间差异无统计学意义(P>0.05),具有可比性;性成熟时体质量、颅骨径线、脑容积三组间均无差异(P>0.05),仅SOC组平均颅骨厚度较大(P<0.05);缺损内径方面SD组与TMR组无差异(P>0.05),且与术前相比均呈狭长形变;旷场实验中总路程、平均速度和静止时间及部分区域数据方面SD组与其他组有差异(P<0.05);Morris水迷宫实验显示第5天逃避潜伏期、首次穿越平台时间和目标象限时间占比等SD组与其他组均有差异(P<0.05)。结论:颅骨缺损未行修补对幼龄大鼠颅骨的正常生长无明显影响,但可能影响其智力发育;钛网修补并不会...     

血小板活化因子、癌胚抗原、糖类抗原724在结直肠癌中的表达及与临床病理特征的关系

目的:探讨血小板活化因子(PAF)、癌胚抗原(CEA)、糖类抗原724(CA-724)在结直肠癌(CRC)患者术前血清中的阳性表达率及与临床病理特征的关系、发病的独立危险因素。方法:选取2019年12月至2021年10月于包头医学院第一附属医院就诊的CRC患者75例为CRC组,另选取同时期在本院体检的健康志愿者75例为对照组。采用酶联免疫吸附(ELISA)法分别检测CRC患者术前及对照组的晨空腹外周静脉血PAF含量;回顾性分析上述入组患者术前血清CEA、CA-724含量,进行统计分析。结果:(1)CRC组PAF、CEA、CA-724单独检测和联合检测的阳性率分别为25.33%、42.67%、30.67%、74.67%,均高于对照组,且联合检测的阳性率均高于单独检测指标的阳性率,组间差异均具有统计学意义(P<0.05);(2)单因素方差分析结果显示,血清CEA表达水平的影响因素为患者的淋巴结转移(P<0.05);血清CA-724表达水平的影响因素为患者的年龄(P<0.05);(3)二元Logistic回归分析结果显示,PAF表达在临床病理特征之间的差异无统计学意义(P&...     

环氧酶-2抑制剂对关节炎大鼠小肠黏膜的影响

目的 探讨环氧酶-2抑制剂对关节炎大鼠小肠黏膜的影响。方法 将32只雄性SD大鼠随机分为空白对照组、造模对照组、空白给药组和造模给药组,造模对照组、造模给药组给予弗氏完全佐剂右后足跖注射,空白对照组、空白给药组注射等量生理盐水。1周后造模给药组、空白给药组给予选择性环氧酶-2抑制剂塞来昔布（溶于1%甲基纤维素）灌胃28 d,空白对照组、造模对照组给予等量溶剂。处死大鼠后观察小肠黏膜大体损伤、病理评分,酶联免疫吸附试验检测末段小肠前列腺素浓度。结果 造模对照组与造模给药组模型复制第7天的足周径比较,差异无统计学意义（P>0.05）,但两组分别与空白对照组和空白给药组比较,差异有统计学意义（P <0.05）,空白对照组与空白给药组比较,差异无统计学意义（P>0.05）。空白对照组与造模对照组小肠黏膜损伤面积比较,差异有统计学意义（P <0.05）,空白给药组与空白对照组比较,差异有统计学意义（P <0.05）。造模对照组、空白给药组和造模给药组组间小肠黏膜病理评分比较,差异无统计学意义（P>0.05）,且空白对照组与其他3组比较,差异有统计学意义（P &...