The epiphyseal scar joint line distance and age are important factors in determining the optimal screw length for medial malleoli fractures

AimThe screw length is important to achieve a stable fixation for medial malleoli fractures. We aimed to evaluate the optimal screw length for different age groups in surgically treated medial malleoli fractures. The second aim was to identify the utility of the distance of epiphyseal scar to joint line or joint line to medullary space for assessment of screw length.Material method368 X-rays and computed tomography (CT) images of ankle joints were retrospectively evaluated for optimal screw length, epiphyseal scar to joint line distance, joint to medullary space distance. The mean screw length for each decade was calculated. The correlations of screw length with age, screw length with distance of epiphyseal scar to joint line, and screw length with distance of joint line to medullary space were evaluated.ResultsThe optimal screw length was obviously decreased in patients in 61–70 and >70 years old group (p = 0.002). As the distance of epiphyseal scar from joint line was increased, the optimal length of screw was also increased (p = 0.001). The distance of epiphyseal scar from joint line was decreased by age (p = 0.011).ConclusionThe optimal screw length was decreased by age and the epiphyseal scar to joint line distance could be a clue for optimal screw length in medial malleoli fractures.     

Reoperation rates and risk factors for revision 4 years after dynamic stabilization of the lumbar spine

Background Context

The concept of dynamic stabilization (DS) of the lumbar spine for treatment of degenerative instability has been introduced almost two decades ago. Dynamic stabilization follows the principle of controlling movement in the coronal plane by providing load transfer of the spinal segment without fusion and, at the same time, reducing side effects such as adjacent segment disease (ASD). So far, only little is known about revision rates after DS due to ASD and screw loosening (SL).

Particulate endocytosis mediates biological responses of human mesenchymal stem cells to titanium wear debris.

Continual loading and articulation cycles undergone by metallic (e.g., titanium) alloy arthroplasty prostheses lead to liberation of a large number of metallic debris particulates, which have long been implicated as a primary cause of periprosthetic osteolysis and postarthroplasty aseptic implant loosening. Long-term stability of total joint replacement prostheses relies on proper integration between implant biomaterial and osseous tissue, and factors that interfere with this integration are likely to cause osteolysis. Because multipotent mesenchymal stem cells (MSCs) located adjacent to the implant have an osteoprogenitor function and are critical contributors to osseous tissue integrity, when their functions or activities are compromised, osteolysis will most likely occur. To date, it is not certain or sufficiently confirmed whether MSCs endocytose titanium particles, and if so, whether particulate endocytosis has any effect on cellular responses to wear debris. This study seeks to clarify the phenomenon of titanium endocytosis by human MSCs (hMSCs), and investigates the influence of endocytosis on their activities. hMSCs incubated with commercially pure titanium particles exhibited internalized particles, as observed by scanning electron microscopy and confocal laser scanning microscopy, with time-dependent reduction in the number of extracellular particles. Particulate endocytosis was associated with reduced rates of cellular proliferation and cell-substrate adhesion, suppressed osteogenic differentiation, and increased rate of apoptosis. These cellular effects of exposure to titanium particles were reduced when endocytosis was inhibited by treatment with cytochalasin D, and no significant effect was seen when hMSCs were treated only with conditioned medium obtained from particulate-treated cells. These findings strongly suggest that the biological responses of hMSCs to wear debris are triggered primarily by the direct endocytosis of titanium particulates, and not mediated by secreted soluble factors. In this manner, therapeutical approaches that suppress particle endocytosis could reduce the bioreactivity of hMSCs to particulates, and enhance long-term orthopedic implant prognosis by minimizing wear-debris periprosthethic osteolysis.     

降钙素防治骨质疏松模型兔的人工假体无菌性松动的实验研究

[目的]探讨降钙素对已行人工假体植入骨质疏松模型免的假体无菌性松动防治作用的实验研究。[方法]将30只假体植入模型的骨质疏松症兔随机分成实验组和对照组，各15只。实验组给予鲑鱼降钙素治疗（6U／kg，肌注，隔日1次），而对照组给予等量的生理盐水肌注，持续治疗半年。两组均分别于术前、术后4、8、12和24周检测假体周围感应区（ROI）骨密度（BMD）；于术前及术后4、12、24周行血清骨代谢指标检测：骨特异性碱性磷酸酶（BALP）、骨钙素（BGP）、抗酒石酸酸性磷酸酶-5b（TRAP-5b）；所有动物于术后24周处死，分别行假体拔出实验与扭转实验测定和假体周围骨组织形态计量学分析。[结果]术后24周，实验组假体周围局部感兴趣区BMD增加近5％，而对照组假体周围局部感兴趣区BMD下降了6％，两组比较有显著性差异（P〈0．01）；骨代谢指标中，术后24周实验组的BALP、BGP稍有下降，但组内无显著性差异（P〉0．05），而TRAP-5b有明显下降（P〈0．05），这些指标与对照组比较差异显著（P〈0．05或P〈0．01）；生物力学检测显示，实验组的假体拔出实验较对照组提高了约50％，扭转实验提高近1倍，且两组比较差异显著（P〈0．01）；骨组织形态计量学显示，实验组中反映骨吸收的Oc．No／Tb．Pm、ES／BS明显减少；反映骨量和微结构的％Tb．Ar、Tb．N明显增多，而Tb．Sp明显变窄：反映骨形成与骨矿化的OS／BS、MAR、BFR／TV及％L．Pm也均明显增多；这些指标与对照组比较差异显著（P〈0．01或P〈0．05）。[结论]鲑鱼降钙素能明显减少人工假体周围骨量的丢失和抑制骨溶解；并加快假体周围的骨形成，提高骨密度，促进生理性骨矿化；还能改善骨质量，促进骨微结构改变，提高骨的生物力学特性并增加假体四周的支撑力。其对骨质疏松症兔的假体松动有明显的预防和治疗作用。这对临床预防和治疗人工关节的无菌性松动有很好的指导意义。     

关节镜下可吸收空心界面螺钉固定、四股腘绳肌腱重建前交叉韧带

目的探讨关节镜下可吸收空心界面螺钉固定、四股自体腘绳肌肌腱重建前交叉韧带(anterior cruciate ligament,ACL)的方法及疗效. 方法关节镜下以四股自体腘绳肌肌腱作为ACL替代物,应用(96L-4D)SR-PLA聚丙交酯生物可降解界面螺钉进行移植物固定, 对42例ACL损伤行ACL重建术. 结果 42例术后随访3～22个月,平均11.4月,膝关节活动度均在正常范围.术后Lachman 试验:37例≤1 ,4例2 ,1 例3 .轴移试验:42 例均为阴性.术后Lysholm 评分(89.7 ±9.6)分较术前(49.4±9.1)分显著提高(t=2.12,P=0.038).术后Tegner 活动评分(5.3±1.1)分较术前(2.3±0.7)分显著提高(t=4.13,P=0.008).术后1年MRI示29例可吸收空心界面螺钉部分被吸收;27例重建的韧带位置良好、形态正常;2例韧带在股骨的止点偏前;3例胫骨止点偏前,有轻度顶撞击现象. 结论四股腘绳肌腱是ACL重建的理想替代材料,可吸收空心界面螺钉是ACL重建的理想内固定材料.     

骶骨上关节突关节面5点7点进钉方法的放射解剖学研究

目的 :对骶骨螺钉上关节突关节面 5点 7点进钉方法进行相关的放射解剖学研究。方法 :在 5 0块骶骨标本上 ,用 为 1mm的软钢丝在骶骨翼、骶骨上关节突处紧紧缠绕 2个钢丝圈 ,将 为 3mm的钢珠用胶布固定在 5点 7点处 ,拍骶骨正位片 ,观测钢珠与 2个钢丝圈的位置关系及其至骶管外侧壁、骶骨上面的距离。作经 5点 7点水平平行于S1椎体上面的CT扫描 ,观察骶骨横断面的形态特点 ,测量与矢状面夹角为 0°和向内 10°时的进钉深度。结果 :5点 7点处钢珠均位于上关节突与S1后孔缠绕的钢丝圈显影内 ,位于骶管侧壁钢丝圈显影的外侧 ,钢珠与骶管外侧壁的距离为左侧〔 ( 6 7± 2 3 ) ( 5 0～ 12 0 )〕mm ,右侧〔 ( 6 6± 1 9) ( 5 0～ 11 0 )〕mm ;此点至骶骨上面的距离为左侧〔 ( 11 5± 5 3 ) ( 5 0～ 2 8 0 )〕mm ,右侧〔 ( 11 6± 5 4) ( 5 0～ 2 9 0 )〕mm。CT片显示钉道与矢状面平行( 0°)时 ,进钉深度左侧为〔 ( 3 2 6± 3 5 ) ( 2 4 0～ 40 0 )〕mm ,右侧为〔 ( 3 2 6± 3 5 ) ( 2 4 0～ 42 0 )〕mm ;螺钉向内与矢状面的夹角为 10°时 ,进钉深度左侧为〔 ( 3 8 1± 3 8) ( 3 0 0～ 46 0 )〕mm ,右侧为〔 ( 3 8 0± 3 9) ( 3 0 0～ 46 0 )〕mm。结论 :骶骨上关节突恒定存在 ,将每侧上关节     

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。     

屈膝过程中的胫股运动特性分析

本文采用三维位移测量方法，测试１０例离体人膝标本的胫股关节三维运动特性。发现屈膝过程中，胫股运动也具有典型的三维运动特点。其中在屈膝初期的３０°内，胫骨内旋最明显并伴有胫骨内翻现象，平均内旋８°，内翻６－７ｍｍ，膝关节完全伸直时胫股扣锁使膝关节稳定，屈曲时胫股“解锁”使膝关节松弛，具重要的临床意义，同时提示，在解释传统的胫股扣锁现象时不应遗漏伴随发生的胫骨内／外翻现象。     

闭合复位经皮螺钉内固定治疗跖跗关节损伤

目的探讨应用闭合复位经皮螺钉内固定治疗跖跗关节损伤的临床疗效。方法自2003年1月～2005年6月应用闭合复位经皮螺钉内固定治疗跖跗关节损伤26例。按照Myerson分类:中间柱损伤13例,内侧、中间柱合并损伤7例,内侧、中间、外侧柱三柱损伤6例。结果本组切口均一期愈合,平均手术时间为40min(30～70min),切口长度平均为5mm;所有患者获平均11.4个月(6～17个月)随访,根据美国足踝骨科协会(AOFAS)评分平均为87分,患者术后平均5.3个月(3～11个月)恢复正常生活。结论闭合复位经皮螺钉内固定手术创伤小,软组织并发症低,能有效治疗跖跗关节复合体损伤;中间柱复位并沿Lisfranc韧带方向插入螺钉内固定是重建跖跗关节复合体稳定性的关键。     

寰椎椎弓根螺钉置钉的解剖与临床研究

目的：建立和验证寰椎后路椎弓根螺钉固定的进钉技术。方法：利用40套干燥配套寰枢椎标本测量进钉技术的相关参数，而后临床应用该技术方法置钉并行X线、CT复查其准确性。结果：寰椎椎弓根平均宽度为7．78mm，进钉点在寰椎椎弓根中线外侧2．2m，螺钉进钉点可由经枢椎下关节突中点的纵垂线来确定；手术中该方法不仅能简化操作过程，而且术后检查发现螺钉均准确置入。结论：用枢椎下关节突中点作为术中判定寰椎椎弓根螺钉进钉点的方法准确可靠。