关节镜下股骨单隧道与双隧道重建后十字韧带的疗效分析

目的分析比较关节镜下单束单隧道与双束股骨双隧道重建后十字韧带(PCL)术后的临床效果。方法1999年1月～2001年12月,采用单束前外束重建法重建PCL 18例,男14例,女4例;年龄18～50岁,平均35.5岁;右膝12例,左膝6例。移植物为骨-髌腱(中1/3)-骨的11例,半腱肌腱和股薄肌腱的7例。于PCL股骨附着点解剖中心的稍前方钻取股骨隧道,屈膝70°,拉紧并固定移植物。2000年1月～2002年12月,采用双束股骨双隧道法重建PCL12例,男10例,女2例;年龄21～47岁,平均33岁;右膝9例,左膝3例。移植物为半腱肌腱和股薄肌腱的7例,一端带髌骨块的股四头肌肌腱的5例。将肌腱编织分为两束。于股骨侧钻取双隧道。两束分别于屈膝70°和0°时拉紧并固定。结果采用前外束重建法的18例患者平均随访23个月,采用双束股骨双隧道重建法的12例患者平均随访17个月。前外束重建组与双束股骨双隧道重建组随访时的Lysholm评分分别为(92.4±3.7)分和(94.3±3.4)分,两组间差异无显著性(P>0.05)。屈膝0°和30°时,前外束重建组的胫骨后移距离是(5.9±0.4)mm和(6.2±0.5)mm,双束股骨双隧道重建组是(3.5±0.3)mm和(4.0±0.4)mm,两组间差异有显著性(P<0.05);屈膝60°和90°时,两组胫骨后移距离差异无显著性(P>0.05)。结论双束股骨双隧道重建PCL的方法优于前外     

A simple mechanical model using a piston to produce localized cerebral contusions in pigs

Summary A simple mechanical model using a piston to produce localized cerebral contusions in pigs, is presented.The precision and reproducibility of the method are described by the biomechanical and pathological results.There are only pathological changes with haemorrhage and laceration close to the place of entry of the piston. The changes in the physiological parameters also indicate that the damage is focal.In this model, when kept intact, the dura mater offers considerable protection as no pathological changes in the brain are observed even when the energy at the time of the contusion is increased to twice the values which, when the dura is open, cause considerable damage.     

不同保存方法对肌腱生物力学特征的影响

目的　分析 5种常用的肌腱保存方法对肌腱生物力学的影响。从生物力学的角度寻找最佳的保存方法 ,用于指导临床肌腱移植。方法　采用 5 0只健康白色Leghorn鸡 ,随机分成 5组 ,建立 2 ,3 ,4爪浅屈肌腱做供体模型。分别采用常用的保存组织方法 :低温冷藏 ,70 %酒精 ,10 %福尔马林 ,85 %甘油。结果　低温冷藏组在最大抗拉伸力Pmax及最大延伸率δmax与新鲜肌腱组比较 ,无明显差异。酒精组、85 %甘油组最大抗拉伸力较高 ,而福尔马林组最低。结论　低温冷藏的方法保存肌腱 ,从生物力学角度考虑是最佳的保存方法     

Functional anatomy and biomechanics of the meniscus

The meniscus is no longer considered the evolutionary remnant in the knee joint.Rather, it is now well established as an important structure that is integral to the complex biomechanics and proper functioning of the knee. The medial and lateral menisci form two crescent-shaped wedges of fibrocartilage between the femoral condyles and tibial plateaus.The knee joint biomechanics are based on a complex interaction of these intra-articular structures. The functions ascribed to the menisci include load transmission, shock absorption, stability, proprioception, joint lubrication, and joint nutrition. Load transmission generally is accepted as one of its primary functions. The menisci transmit a portion of the axial forces across the knee joint by converting this load into “hoop stresses.” This is accomplished by their unique shape, composition, and anatomic attachments. The menisci are relatively mobile structures and their motion during knee flexion also is determined by their shape and soft tissue attachments/constraints. Preservation of the meniscal functions is essential, and the authors review the basic anatomic and biomechanical concepts necessary to understand techniques for repair and restoration of these functions.     

Automated assessment of cervical dystonia.

We developed an automated and objective method to measure posture and voluntary movements in patients with cervical dystonia using Fastrack, an electromagnetic system consisting of a stationary transmitter station and four sensors. The junction lines between the sensors attached to the head produced geometrical figures on which the corresponding aspects of the head were superimposed. The head position in the space was reconstructed and observed from axial, sagittal, and coronal planes. Four patients with cervical dystonia and 6 healthy subjects were studied. Each patient was representative of one of the typical patterns of cervical dystonia. The study allowed the authors to collect quantitative data on posture and range of motion of the head. This pilot study demonstrates the efficacy of the Fastrack system to objectively measure the head position in cervical dystonia patients.     

Surface movement errors in shank kinematics and knee kinetics during gait

The movement of surface mounted targets (SMT) on a shell at the mid-shank and of bone mounted targets attached to the distal shank using a Percutaneous Skeletal Tracker (PST) were simultaneously measured during free-speed walking of three adult subjects having different body types. Surface movement errors in shank kinematic estimates were determined by expressing the segmental motion derived from the SMT relative to the PST-based segment coordinate system (SCS) located at the segment center of gravity. The greatest errors were along and around the shank longitudinal axis, with peak magnitudes of 10 mm of translation and 8° of rotation in one subject. Estimates of knee joint center locations differed by less than 11 mm in each SCS direction. Differences in estimates of net knee joint forces and moments were most prominent during stance phase, with magnitudes up to 39 N in the shank mediolateral direction and 9 N.m about the mediolateral axis. The differences in kinetics were primarily related to the effect of segment position and orientation on the expression of joint forces and on the magnitude and expression of joint moments.     

Gait biomechanics and the evolution of total joint replacement

The history and evolution of total knee and total hip replacement has been influenced substantially by the knowledge obtained from gait analysis studies. Many of the mechanical problems associated with these devices have been analyzed and evaluated in terms of the mechanics of walking. The magnitude and pattern of the forces at the hip and knee joints derived from gait analysis studies have provided valuable input into the design criteria of both total hip and total knee replacements. Information generated from the gait analysis of patients with total joint replacements has provided objective criteria for assessing functional recovery following this procedure. In addition to providing a basis for design evaluation, the key to the analysis of function following joint replacement is the ability to identify functional adaptations specific to design features. Gait analysis provides a unique opportunity to obtain objective information that cannot be obtained through other clinical means and provides a means for evaluating current designs and future design modifications.     

膝关节 Q 角变化规律的实验研究

本研究利用精密三维位移测读仪，研究分析了Ｑ角的变化趋势，以及对髌股关节运动的影响。研究结果表明，Ｑ角是一空间夹角，随屈膝角的增大而增大。力线在平面上的投影所呈的平面夹角Ｑｐ也就是通常所指的Ｑ角，在屈膝１５°左右达最大，而在９０°左右达最小。整个屈膝过程中，ＱＰ在５°－１５°之间变化，变化幅度达１０°左右。     

板股韧带的MRI研究及临床意义

目的　明确板股韧带正常MRI表现 ,建立由它所致假撕裂与外侧半月板后角真撕裂的鉴别方法。资料与方法　采用 6 0侧正常膝进行矢状和冠状位MR扫描 ,观察板股韧带的MRI表现。结果　板股韧带显示率为88.3% (5 3侧 ) ,其中板股前韧带为 2 6 .7% (16侧 )、板股后韧带为 86 .7% (5 2侧 )和两条韧带同时存在为 2 3.3% (14侧 )。板股韧带在矢状像上表现为位于后交叉韧带前或后方的类圆形或短棒状低信号结构 ,而在冠状像上表现为自外侧半月板后角至股骨内侧髁外侧面的条带样低信号结构。在矢状像上 ,5 2 .8% (2 8/5 3)板股韧带与外侧半月板后角之间显示出一线样高信号 ,被称为假撕裂 ,易与外侧半月板后角撕裂混淆。但假撕裂仅有两种走行方向即后下斜行 (2 1/2 8)或垂直方向 (7/2 8)。结论　根据假撕裂位置、方向以及冠状像和连续矢状面的观察 ,可正确区分外侧半月板后角真假撕裂     

Closed suction drainage after orthopaedic surgery: evidence versus practice

Abstract Closed suction drainage systems are commonly used in orthopaedic surgery, particularly in joint arthroplasty. The rationale for the use of drains is a theoretical reduction of wound haematomas and infection. However the benefit of using drains after total hip or knee arthroplasty is controversial. Several reports have shown that the use of drains does not reduce infection and morbidity and is an unnecessary and potentially dangerous practice. In fact most studies highlighted that at best their use appears to make no difference to important clinical outcomes. Recently a metaanalysis raised the question about the usefulness of closed suction drainage again, concluding that it has no major benefits. The purpose of this study was to review the evidences available concerning the utility of closed suction drainage outlining that this practice is not supported by clinical evidence.