Biomechanical comparison of three internal fixation configurations for low transcondylar fractures of the distal humerus

BackgroundWe aimed to evaluate the biomechanical stiffness and strength of different internal fixation configurations and find suitable treatment strategies for low transcondylar fractures of the distal humerus.Methods and materialsThirty 4^th generation composite humeri were used to create low transcondylar fracture models that were fixed by orthogonal and parallel double plates as well as posterolateral plate and medial screw (PPMS) configurations (n=10 in each group) using an anatomical locking compression plate-screw system and fully threaded medial cortical screws. Posterior bending (maximum 50 N), axial loading (maximum 200 N) and internal rotation (maximum 10 N·m) were tested, in that order, for each specimen. Stiffness under different biomechanical settings among different configurations were compared. Another 18 sets of fracture models were created using these three configurations (n=6 in each group) and the load to failure under axial loading among different configurations was compared.ResultsUnder posterior bending, the stiffness of parallel group was higher than orthogonal group (P<0.001), and orthogonal group was higher than PPMS group (P<0.001). Under axial loading, the stiffness of parallel group was higher than orthogonal group (P=0.001) and PPMS group (P<0.001); however, the difference between orthogonal and PPMS group was not statistically significant (P>0.05). Under internal rotation, the stiffness of parallel group was higher than orthogonal group (P=0.044), and orthogonal group was higher than PPMS group (P=0.029). In failure test under axial loading, the load to failure in the orthogonal group was lower than parallel group (P=0.009) and PPMS group (P=0.021), but the difference between parallel group and PPMS group was not statistically significant (P>0.05). All specimens in orthogonal group demonstrated “distal medial failure”; most specimens had “distal medial and trochlear failure” in the parallel group; most specimens exhibited “contact failure” in the PPMS group.ConclusionFor treating low transcondylar fractures, the overall stiffness and strength of the parallel configuration were superior to those of the orthogonal and PPMS configurations. Nevertheless, the PPMS configuration can provide adequate stability and stiffness comparable to double-plate configurations under axial loading. Therefore, the PPMS construct may have certain clinical value.     

短缩-延长肢体治疗胫骨骨缺损合并软组织缺损

目的探索单纯使用Orthofix重建外固定架通过短缩一延长肢体治疗胫骨骨缺损合并软组织缺损的可行性。方法2001年7月～2006年7月收治胫骨骨缺损合并软组织缺损患者39例，其中37例为胫骨感染性骨折不愈合，2例为胫骨开放性骨折（GustiloⅢB型1例，Gustilo ⅢC型1例）。在患肢上安放Orthofix重建外固定架。清创术后小腿胫前内侧软组织平均缺损12cm（6～24cm），胫骨骨缺损平均9cm（4～22cm）。对胫骨骨缺损〈5cm的患者使用一期清创．腓骨截骨．胫骨缺损端加压。对22例胫骨缺损〉5cm的患者采用清创，腓骨截骨．短缩肢体〈5cm。对炎症局限、胫骨截骨部皮肤正常而且远离伤口的患者同期行胫骨截骨术，否则于1．0～1．5个月后二期行胫骨截骨术延长恢复肢体的长度。结果所有患者平均随访14个月（10～44个月）。骨缺损均得以重建，患肢肢体长度与健侧之差小于5mm，骨折愈合，无感染复发，创面均闭合。1例术后出现腓总神经麻痹，术后2个月恢复。4例胫骨缺损患者诉膝部疼痛。5例胫骨蠓损患者出现马蹄内翻足。2例胫骨缺损出现下胫腓分离。1例再骨折。结论使用Orthofix重建外固定架进行短缩．延长肢体是治疗胫骨骨缺损合并软组织缺损的有效方法，但应谨慎使用。对于软组织缺损少的小腿一期短缩的安全限度为3cm，最终短缩6cm。对于软组织缺损较大的急性胫骨开放骨折小腿一期可以短缩9cm。     

双平面骨科机器人系统辅助骶髂关节螺钉置入的实验研究

目的本研究应用双平面骨科机器人系统进行尸体骨骨盆骶髂关节螺钉置入的实验研究,评估该系统的安全性和有效性。方法双平面骨科机器人系统是由北京航空航天大学和北京积水潭医院联合开发的一种基于术中X线图像的手术导航系统。在该系统辅助下对4具尸体骨骨盆进行骶髂关节螺钉置入,共12枚空心钉,均置入S1。作为对比,由同一位医生操作,应用传统方法在C型臂透视控制下对模型骨盆进行骶髂关节螺钉置入,同样为12枚空心钉。记录从采集图像到置入空心钉导针所需透视的次数、透视累计时间及操作时间,并进行统计学分析。置入骶髂关节螺钉后,通过目测、透视和锯开骶骨直接测量的方法检查螺钉的位置。结果在机器人导航辅助下,置入一枚导针的平均透视次数是2.5次,平均透视累计时间为1.5s,平均操作时间为253s;12枚骶髂关节螺钉均在安全区内。在透视控制下徒手操作,置入每枚导针的平均透视次数是20.3次,平均透视累计时间为13.7s,平均操作时间为246s;12枚骶髂关节螺钉中,两枚螺钉误置。应用双平面骨科机器人系统辅助操作的透视次数和透视累计时间少于徒手操作,二者差异有显著性意义(P<0.05)。而操作时间二者差异无显著性意义(P>0.05)。结论双平面骨科机器人系统为骶髂关节螺钉置入提供精准的空间定位和稳定的路径导航,而这一切都在短短的数分钟之内完成,具备极好的安全性和高效性,并使患者和医生受到的X线照射量显著减少。目前的应用结果鼓舞我们进一步的临床实验应用。     

计算机辅助带锁髓内钉固定胫骨骨折全程规划手术系统的实验研究

目的评价计算机辅助带锁髓内钉固定胫骨骨折全程手术规划系统的有效性及临床可行性。方法在分析系统结构和操作流程的基础上,利用塑料胫骨模型(9根)和尸体胫骨(12具下肢肢体)进行基于C型臂透视图像的术中骨折肢体图像拼接、骨折闭合复位及髓内钉置入仿真测量实验；利用胫骨模型及尸体胫骨进行图像拼接精度分析,以验证图像拼接与规划模块的正确性。利用尸体胫骨进行计算机辅助骨折闭合复位试验,分析骨折复位机构模块的操作可行性。结果图像拼接模块只需术中采集7～10张有效的C型臂图像即可拼接出下肢长骨的全景图像,为采集图像所需的术中透视时间为(19．75±0．61)s；计算机进行X线透视图像采集和拼接总时间为(4．17±0．86)min；塑料模型拼接精度达(1．26±0．76)mm。结论该系统实现了基于C型臂拼接图像的计算机辅助胫骨骨折髓内钉内固定全程手术规划,术中可完成骨折复位图像分析、手术规划、虚拟仿真,髓内钉型号选择以及骨折复位等关键操作,为计算机辅助骨科手术系统治疗长骨骨折搭建了精确、安全、稳定的软硬件技术平台。     

带锁髓内钉治疗新鲜四肢长骨干骨折1224例疗效分析

目的总结带锁髓内钉治疗肱骨干、股骨干、股骨髁上、胫骨干和转子间骨折的疗效。方法自1996年10月至2004年6月间使用带锁髓内钉治疗的有完整资料的新鲜四肢骨折1224例,男778例,女446例;平均年龄39岁(16￣92岁)。骨折位于肱骨干92例,股骨转子间210例,股骨干488例,股骨髁上92例,胫骨342例。闭合骨折按AO分型:A型642例;B型364例;C型218例。开放骨折15例(GustiloⅠ型8例,GustiloⅡ型7例)。受伤至手术时间平均为8d(3h￣33d)。闭合复位1203例,切开复位23例;扩髓409例,非扩髓815例。结果平均随访时间为24个月(6￣70个月)。1204例骨折愈合,愈合率为98.2%,平均愈合时间为5个月(3￣12个月)。骨折不愈合22例,其中肱骨4例,股骨8例,股骨髁上4例,胫骨6例,总不愈合率为1.8%。术后无急性感染发生,3例发生晚期深部感染,总感染率为0.2%。术中16例发生严重骨折劈裂,4例为肱骨逆行髓内钉固定,4例Gamma钉固定,9例为股骨逆行髓内钉固定,占1.3%。6例发生医原性神经损伤,占0.4%。股骨髓内钉主钉断裂1例,锁钉断裂9例(0.6%)。晚期髓内钉末端骨折3例,占0.2%。53例主诉髓内钉尾端部位不适,占4.3%。结论闭合复位带锁髓内钉治疗骨干骨折在骨折愈合率、感染率、出血量、功能恢复情况和早期活动方面均较满意,是治疗骨干骨折较好的方法,但     

医用机器人辅助股骨带锁髓内针远端锁钉瞄准系统的实验研究

目的研制在骨折治疗中精确定位的机器人辅助远端锁钉瞄准系统。方法在以股骨髓内针远端锁钉植入手术中,采用模块化、小型化的并联机器人结构设计,应用机械臂空间定位技术,双目视觉、6自由度的机器人辅助髓内针远端锁钉瞄准系统。结合C型臂定位并实施导航控制进行远端锁钉植入。髓内针被分别置入塑料股骨(Swiss Sybone,5根,35孔)、人类干股骨标本(2根,12孔)、新鲜人尸体大腿(1具,6孔)。非扩髓型髓内针的尺寸范围从9/310到12/340。应用机器人辅助瞄准系统对上述髓内针进行远端锁钉植入,术中C型臂透视确认螺钉准确置入,记录锁钉植入过程的X线透视时间。结果所有远端锁孔被成功地锁定。在53个锁孔中,6例(11.1%)钻头触到锁定孔道,仍顺利穿过锁孔,没有对髓内针造成损伤。螺钉植入过程中需要的术中X线透视时间为1.8s±0.3s。结论医用机器人使仅应用两幅计算机校准的X线图像,不需要额外的术中X线透视来导航器械,手术过程中总的X线透射时间显著减少。人机交互功能操作易于掌握,可作为机器人辅助长骨治疗中精确定位和稳定操作的技术平台。     

Macroscopic and Histological Evaluations of Meniscal Allograft Transplantation Using Gamma Irradiated Meniscus: A Comparative in Vivo Animal Study

Background:

Many studies suggest that the gamma irradiation decreases allograft strength in a dose-dependent manner. However, no study has demonstrated that this decrease in strength translates into higher failure rate in meniscal allograft transplantation (MAT). The aim of this study was to investigate the effects of gamma irradiation on macroscopic and histological alterations of transplanted meniscal tissue and joint cartilage after MAT.

Methods:

Medial total meniscectomies were performed on the right knees of 60 New Zealand white rabbits. All meniscal allografts were divided into three groups (20 in each group) and then sterilized with 0 Mrad, 1.5 Mrad, or 2.5 Mrad of gamma irradiation. For each group, 5 menisci were randomly chosen for scanning electron microscopic (SEM) analysis and the remaining 15 were prepared for MAT surgeries. Forty-five right knees received MAT surgeries (0 Mrad group, 1.5 Mrad group, 2.5 Mrad group, 15 in each group), whereas the remaining 15 only received medial meniscectomy (Meni group). The left knees of the Meni group were chosen as the Sham group (n = 15). All the rabbits were sacrificed at week 24 postoperatively. Cartilage of the medial compartment of each group was evaluated macroscopically using the International Cartilage Repair Society (ICRS) score and then histologically using the Mankin score based on the Masson Trichrome staining.

Results:

The SEM analysis confirmed that the meniscal collagen fibers would be significantly damaged as the dose of gamma irradiation increased. At week 24, the overall scores of macroscopic evaluations of the transplanted meniscal tissue showed no significant differences among the three groups receiving MAT surgeries, except for 2 in the 2.5 Mrad group presented partial radial tears at midbody. The ICRS scores and the Mankin scores showed the lowest in the Sham group and the highest in the Meni group (P < 0.05). For the three groups receiving MAT surgeries, the 2.5 Mrad group showed significant higher ICRS scores and Mankin scores than both the 0 Mrad group and the 1.5 Mrad group (P < 0.05). Whereas the 1.5 Mrad group presented similar results to the 0 Mrad group concerning both the ICRS scores and the Mankin scores.

Conclusions:

The current in vivo animal study proved that although the meniscal collagen fibers were damaged after gamma irradiation, the failure rate of MAT surgeries might not significantly increase if the irradiation dose was <1.5 Mrad for New Zealand white rabbits.     

富血小板血浆对兔骨关节炎软骨中基质金属蛋白酶-13表达的影响

目的 探讨富血小板血浆(platelet-rich plasm,PRP)抑制兔骨关节炎软骨表达基质金属蛋白酶-13(matrix metalloproteinase-13,MMP-13)的表达而发挥软骨保护作用。方法 选取30只成年清洁级新西兰大白兔,采用数字表法随机分为对照组、关节炎组、PRP组,每组各10只。关节炎组和PRP组按Hulth法制备后肢左膝关节炎模型,对照组行假手术。造模后第1周开始,各组抽取耳缘静脉血制备PRP 0.2 mL,仅PRP组给予关节腔注射。至第6周处死实验动物,获取各组左膝关节,分别行软骨组织HE染色测量软骨厚度,免疫组织化学染色计数MMP-13阳性细胞数,免疫荧光及Western blotting法检测MMP-13表达量。结果 对照组显示关节软骨形态接近正常,关节炎组软骨破坏明显,而PRP干预组较关节炎组,关节厚度得以保留,MMP-13阳性细胞及其表达量明显受到抑制。结论 PRP可减少MMP-13软骨细胞的数量和抑制MMP-13表达而发挥软骨保护作用。     

肌肉骨骼系统慢性疼痛管理专家共识

肌肉骨骼系统慢性疼痛是临床最常见的慢性疼痛。目前,国内外医师对慢性疼痛的认识、临床实践环境、镇痛药物种类/使用经验/了解程度、医保药品收录均有差异,故有效、规范化的慢性疼痛管理显得尤为必要。因此,亟待制定完善的、基于生物-心理-社会医学等因素的跨学科慢性疼痛管理共识,提高广大医务人员对慢性疼痛的认识与重视、规范指导慢性疼痛的管理,提高医疗质量、降低医疗成本,消除患者感觉、情感、认知和社会维度的痛苦体验,在治疗患者原发疾病的同时,改善患者的心理需求和社会功能需求。通过查阅文献,本共识专家组遵循循证医学原则,经过反复讨论和通信修改,对肌肉骨骼系统慢性疼痛管理达成共识,供广大骨科医师在临床工作中参考。     

全肘关节置换手术入路的选择与现状

全肘关节置换术最早主要用于治疗风湿性关节炎,但是随着近十几年来技术的进步,其适应证已扩大到创伤后不稳定、创伤性关节炎以及老年人新鲜肱骨远端骨折。但是其术后伤口感染、不愈合、尺神经损伤以及肱三头肌肌力下降等并发症一直是困扰临床骨科医师的问题。全肘关节置换术接受程度最为广泛的入路为Bryan-Morrey入路,近年保留肱三头肌鹰嘴附丽点的入路逐渐增多。本文回顾国内外全肘关节置换术相关的入路报道以及生物力学研究,对全肘关节置换手术入路的选择与现状做一综述。