前交叉韧带损伤后胫骨前移征的发生率及临床特点

目的:探究膝关节前交叉韧带损伤后胫骨前移征的发生率及临床特点。方法:对153例连续的前交叉韧带损伤患者行膝关节伸直位核磁共振扫描。根据矢状位下外侧胫骨平台后缘与股骨外侧髁后缘的相对位置,将患者分为胫骨前移征阳性组与胫骨前移征阴性组。此外,分别对比两组患者的胫骨平台后倾角、前外侧韧带连续性以及外侧半月板后角的完整性,以期找到造成胫骨前移征阳性的危险因素。结果:入选的153例患者中,共有46例存在胫骨前移。其中,胫骨前移征阳性组胫骨平台后倾角显著大于阴性组患者(15.4°>8.8°,P<0.01),而前外侧韧带连续性以及外侧半月板后角完整性在两组患者中差异均无统计学意义。结论:本研究中,前交叉韧带损伤后静态胫骨前移征的发生率为30.1%,该现象可能与胫骨平台后倾角异常增大有关。     

膝关节盘状半月板类型及损伤的MRI分析

目的探讨外侧盘状半月板的MRI分型特征及不同类型盘状半月板撕裂的发生率.资料与方法将89例MRI表现典型的外侧盘状半月板分作两组,即未成年组和成年组,其中未成年组35例(36膝),4～17岁(平均13.2岁);成年组54例(57膝),18～74岁(平均42.0岁).将盘状半月板分作板型、楔型、肥角型.分析不同类型的盘状半月板合并半月板撕裂的发生率.结果未成年组板型26膝、楔型4膝、肥角型6膝;成年组板型36膝、楔形15膝、肥角型6膝.两组盘状半月板类型的发生比率无显著性差异(P＞0.10).无论未成年组或成年组均以板型常见.不同类型盘状半月板发生撕裂的比率有显著性差异(P＜0.005),肥角型全部显示半月板撕裂,板型盘状半月板撕裂比率高于楔型.结论无论成年组或未成年组的盘状半月板多见于外侧,其盘状半月板类型的分布两组间无显著差异.而不同类型的盘状半月板合并半月板撕裂的概率是有差异的,因此,MRI检查对临床确定治疗盘状半月板的方案很有帮助.     

膝关节盘状半月板分型与撕裂类型相关性的MRI分析

目的:进行盘状半月板的流行病学研究,探讨膝关节盘状半月板的诊断标准、分型及其与年龄、撕裂类型的关系,以提高对盘状半月板及撕裂MRI表现的认识。方法:对842例诊断为盘状半月板的患者按年龄分为≤19岁、20³9岁、4039岁、40⁵9岁、≥60岁组。对全部患者冠状面髁间棘层面半月板宽度与胫骨平台宽度之比(板面比)、矢状面"领结样"改变层面中半月板后角最厚层面的厚度及矢状面"领结样"改变层数进行测量、分析。根据盘状半月板MRI表现,分为板型、楔型、肥角型。分析盘状半月板分型、年龄与撕裂类型的关系。结果:盘状半月板以外侧多见,女性发病率是男性的1.64倍。842例中,板型535例、楔型274例、肥角型33例。半月板撕裂354例,撕裂率为42.0%。842例板/面比均≥0.20,矢状面"领结样"改变层面中半月板后角最厚层面的厚度≥4.40mm。盘状半月板分型与撕裂类型及年龄分布有关系,而年龄分布与撕裂类型无明显相关。结论:盘状半月板多见于外侧,常伴半月板撕裂。板面比≥0.20、矢状面"领结样"改变层面中半月板后角最厚层面的厚度≥4.40mm、矢状面连续≥3层"领结样"改变,为盘状半月板的MRI诊断标准;盘状半月板分型与撕裂类型有关系;年龄可影响盘状半月板分型。     

膝关节盘状半月板及撕裂的MRI诊断

目的 探讨盘状半月板的MRl分型及其撕裂的MRI诊断.方法 对55例(57膝)经手术或关节镜证实且有完整MRI资料的盘状半月板进行回顾性分析,观察盘状半月板的形态、大小及信号改变,包括半月板宽度和厚度的测量.结果 57膝盘状半月板,56膝发生在外侧,只1膝在内侧.57膝中,板型34膝,楔型15膝,肥角型8膝,其中46膝盘状半月板发生撕裂、7膝伴有变性.结论 盘状半月板多见于外侧,且常并发半月板撕裂或变性.     

前交叉韧带缺失对膝半月板各部分应力影响的有限元研究北大核心CSCD

目的:采用三维有限元力学分析法,对比分析前交叉韧带(anterior cruciate ligament,ACL)正常时和缺失后膝关节半月板前角、体部和后角的应力变化。方法:构建并运用胫股关节三维有限元模型,模拟ACL正常时和缺失后膝关节在伸直位、15°和30°屈曲位的运动状态,并在股骨上施加700 N轴向载荷和134 N后向载荷,比较ACL正常时和缺失后内、外侧半月板前角、体部和后角各自的应力分布变化。结果:当ACL缺失后,在膝关节伸直时,内侧半月板前角的应力比正常膝增加100.7%,大于外侧半月板前角的应力增幅(30.7%);在15°和30°屈曲位时,内侧半月板后角的应力分别比正常膝增加36.4%和59.7%,而外侧半月板后角的应力增加不明显;除了外侧半月板体部的应力在膝伸直位比正常膝增加39.5%以外,内、外侧半月板体部的应力变化不明显。结论:ACL缺失对半月板各部分应力的影响并不相同,其主要导致内侧半月板前角和后角的应力分别在膝伸直位和屈曲位显著增加。     

前交叉韧带缺失对膝半月板各部分应力影响的有限元研究

目的:采用三维有限元力学分析法,对比分析前交叉韧带(anterior cruciate ligament,ACL)正常时和缺失后膝关节半月板前角、体部和后角的应力变化。方法:构建并运用胫股关节三维有限元模型,模拟ACL正常时和缺失后膝关节在伸直位、15°和30°屈曲位的运动状态,并在股骨上施加700 N轴向载荷和134 N后向载荷,比较ACL正常时和缺失后内、外侧半月板前角、体部和后角各自的应力分布变化。结果:当ACL缺失后,在膝关节伸直时,内侧半月板前角的应力比正常膝增加100.7%,大于外侧半月板前角的应力增幅(30.7%);在15°和30°屈曲位时,内侧半月板后角的应力分别比正常膝增加36.4%和59.7%,而外侧半月板后角的应力增加不明显;除了外侧半月板体部的应力在膝伸直位比正常膝增加39.5%以外,内、外侧半月板体部的应力变化不明显。结论:ACL缺失对半月板各部分应力的影响并不相同,其主要导致内侧半月板前角和后角的应力分别在膝伸直位和屈曲位显著增加。     

半月板根部放射状撕裂MR表现

目的 探讨半月板根部放射状撕裂的MRI表现.方法 回顾性分析17例经关节镜证实半月板根部放射状撕裂MRI表现.结果 17例半月板根部放射状撕裂中,16例位于内侧半月板后角,1例位于外侧半月板后角.MRI表现为根部横断位和冠状位后角条状高信号和矢状位表现为后角弥漫性高信号.同时检出继发征象,包括半月板膨出11例,关节面下骨挫伤13例.17例患者均伴有膝关节退行性改变.结论 膝关节半月板根部放射状撕裂主要发生在内侧半月板后角,MRI可以依据多方位成像显示其多种征象,熟悉这些征象可以帮助放射诊断医师作出正确诊断指导临床治疗方案的实施.     

盘状半月板MRI分型及其表现分析

目的:探讨盘状半月板MRI表现及其分型特点,提高盘状半月板MRI诊断率.材料和方法:将70例行MRI检查并经关节镜证实的盘状半月板分为未成年组、成年组.对全部病例冠状面髁间棘层面半月板宽度与胫骨平台宽度之比(板面比)、矢状面层厚4mm扫描"领结样"改变层数及"领结样"改变最宽层面前后径宽度进行测量、分析.根据盘状半月板MRI表现分为板型、楔型、肥角型.结果:70例盘状半月板中未成年组30例、成年组40例,板型33例、楔型19例、肥角型18例,69例发生不同程度撕裂.整组病例板面比≥20%(P<0.01),各型年龄分布无显著性差异(P>0.05),各型矢状面"领结样"改变最宽层面不全相同(P<0.05).结论:板面比≥20%诊断盘状半月板最可靠,矢状面层厚4mm扫描"领结样"改变层数≥3诊断盘状半月板易发生漏诊,矢状面"领结样"改变最宽层面楔型较肥角型大,年龄可影响盘状半月板分型.     

膝关节盘状半月板的MRI诊断

目的　探讨膝关节盘状半月板的MRI表现以及MRI诊断盘状半月板的标准。材料与方法　对 2 6例经手术或关节镜证实的盘状半月板和 3 0例健康志愿者的膝关节进行MRI检查 ,对正常及盘状半月板的形态、大小及信号改变进行对照观察 ,包括半月板宽度和厚度的测量。结果　 2 6例盘状半月板中 ,2 5例为外侧盘状半月板 ,只有 1例为内侧盘状半月板 ,18例为厚板型 ,8例为楔型。冠状面上 ,盘状半月板体部平均宽度及厚度明显大于正常半月板 ,分别为 2 3 .4mm、11.5mm (P <0 .0 5 )和 3 .2mm、0mm(P <0 .0 1)。但盘状半月板边缘厚度与对侧半月板厚度差超过 2mm者只有 6例。矢状面上 ,连续 3层或 3层以上显示盘状半月板的前后角相连形成“领结”样改变 ,而正常半月板只有 2层有此表现。 2 6例盘状半月板中 ,2 4例并发半月板变性或撕裂。结论　盘状半月板多见于外侧半月板。盘状半月板特征性的MR表现是盘状半月板明显较正常半月板厚、大 ,MRI检查易于诊断。盘状半月板常并发半月板变性或撕裂。     

正常膝关节半月板及关节软骨的低磁场MRI表现

目的:研究正常膝关节半月板及关节软骨的低场MRI表现。材料和方法:选择膝关节无外伤史、无任何临床症状的志愿者28例,按照不同的年龄分为3组。MRI显示正常半月板及关节软骨的外形、信号强度。冠状位T1WI,最厚层面,测量半月板体部厚度;矢状位T1WI,最厚层面,测量半月板前、后角及关节软骨厚度。结果:MRI显示半月板外形均为三角形,厚度随年龄和位置的不同有差异,半月板SET1WI均见不到达关节面的条状高信号。关节软骨的厚度随年龄发生变化,但信号均匀,边缘光整。结论:正常膝关节半月板及关节软骨的厚度随年龄而发生变化,低场MRI半月板内可见线条状高信号,应避免对半月板损伤的误诊。     

MR assessment of movement and morphologic change in the menisci during knee flexion

PURPOSE: To examine movement and morphologic alteration in the menisci during knee flexion. MATERIAL AND METHODS: Twenty healthy knees were imaged at 0 degrees, 45 degrees, and 90 degrees of passive non-weight-bearing flexion in the sagittal plane with MR. In each meniscus, posterior movement distance during knee flexion and the ratio of anteroposterior (a.p.) diameter at flexion to that at extension were calculated. RESULTS: Each meniscus moved posteriorly during knee flexion. Movement was greater in the anterior horn than in the posterior horn, and greater in the medial meniscus than in the lateral meniscus (p<0.05). The a.p. diameter of each meniscus was reduced at flexion (p<0.05). CONCLUSION: Knee flexion normally leads to posterior movement and shortening of the a.p. diameter of the menisci, which may be related to the positioning and curvature of femoral condyles at the femorotibial contact point at knee flexion.     

盘状半月板MRI表现（附56例分析）

目的分析56例盘状半月板MRI表现,以提高盘状半月板诊断正确率.材料和方法经手术、关节镜确诊的56例盘状半月板,对其MR图像不同层面进行测量,参照Crues等有关半月板损伤行MRI分级.结果56例盘状半月板形态学分型凹透镜型29例,厚板型10例,簸箕型5例,后角肥大型8例,不完全型4例,其中央薄弱部分以粉碎性撕裂为主,周缘厚实部分以退变为主,MRI诊断与手术对比总符合率为89.3%;结论对各种盘状半月板的认识有助于提高MRI诊断盘状半月板的正确率,并对外科手术有指导意义.     

Comparison of the insertion of the posterior horn of the lateral meniscus: discoid versus non-discoid

Purpose

The purpose of this study was to compare the insertion sites of the posterior horn between discoid and non-discoid lateral meniscus using magnetic resonance imaging (MRI).

Methods

Two hundred and twenty-seven patients who had MRI scans before surgery and underwent arthroscopy were enroled in this study. A coronal view showing the narrowest width of the midbody of the lateral meniscus was chosen to measure the widths of the entire tibial plateau and the midbody of the lateral meniscus. Considering the ratio of the meniscal width to the tibial plateau width, the patients were divided into non-discoid, incomplete discoid, and complete discoid groups. On a coronal view accurately showing the insertion of the posterior horn of the lateral meniscus, a distance between the peak of the lateral tibial eminence and the centre of the insertion of the posterior horn, and a width of the lateral tibial plateau between the lateral edge of the tibial plateau and the peak of the lateral tibial eminence were measured.

Results

The insertion centre of the posterior horn was located more medially in the incomplete and complete discoid groups than in the non-discoid group (p = 0.003, 0.010, respectively). When individual differences in the knee size were corrected, the insertion centre of the posterior horn in the incomplete discoid and complete discoid groups was located more medially than in the non-discoid group (p = 0.009, 0.003, respectively).

Conclusion

The insertion centre of the posterior horn of the lateral meniscus is located more medially to the apex of the lateral tibial eminence in the discoid group than in the non-discoid group. This finding needs to be considered for an accurate position of the posterior horn of lateral meniscus during the lateral meniscal allograft transplantation.

Level of evidence

IV.

     

Prosthetic replacement of the medial meniscus in cadaveric knees: does the prosthesis mimic the functional behavior of the native meniscus?

Meniscus replacement by a polymer meniscus prosthesis in dogs resulted in generation of new meniscal tissue. HYPOTHESIS: Optimal functioning of the prosthesis would involve realistic deformation and motion patterns of the prosthesis during knee joint motion. STUDY DESIGN: Controlled laboratory study. METHODS: The movements of the meniscus were determined during knee joint flexion and extension with and without internal and external tibial torque by means of roentgen stereophotogrammetric analysis. Subsequently, the meniscus in 6 human cadaveric knee joints was replaced by a meniscus prosthesis. RESULTS: All different parts of the meniscus showed a posterior displacement during knee joint flexion. The anterior horn was more mobile than the posterior horn. The prosthesis mimicked the movements of the meniscus. However, the excursions of the prosthesis on the tibial plateau were less. The knee joint laxity was not significantly higher after replacement with the meniscus prosthesis. CONCLUSIONS: The prosthesis approximated the behavior of the native meniscus. Improvement in both the gliding characteristics of the prosthetic material and the fixation of the prosthesis may improve the function. CLINICAL RELEVANCE: The meniscus prosthesis needs to be optimized to achieve a better initial function in the knee joint.     

Displacement of the medial meniscus within the passive motion characteristics of the human knee joint: an RSA study in human cadaver knees

The objective of this study was to validate an in vitro human cadaver knee-joint model for the evaluation of the meniscal movement during knee-joint flexion. The question was whether our model showed comparable meniscal displacements to those found in earlier meniscal movement studies in vivo. Furthermore, we determined the influence of tibial torque on the meniscal displacement during knee-joint flexion. Three tantalum beads were inserted in the medial meniscus of six human-cadaver joints. The knee joints were placed and loaded in a loading apparatus, and the movements of the beads were determined by means of RSA during knee-joint flexion and extension with and without internal tibial (IT) and external tibial (ET) torque. During flexion without tibial torque, all menisci moved in posterior and lateral direction. The anterior horn showed significantly greater excursions than the posterior horn in both posterior and lateral direction. Internal tibial torque caused an anterior displacement of the pathway on the tibial plateau. External tibial torque caused a posterior displacement of the pathway. External tibial torque restricted the meniscal displacement during the first 30° of knee-joint flexion. The displacements of the meniscus in this experiment were similar to the displacements described in the in vivo MRI studies. Furthermore, the application of tibial torque confirmed the relative immobility of the posterior horn of the meniscus. During external tibial torque, the posterior displacement of the pathway on the tibial plateau during the first 30° of flexion might be restricted by the attached knee-joint capsule or the femoral condyle. This model revealed representative meniscal displacements during simple knee-joint flexion and also during the outer limits of passive knee-joint motion.     

Transverse ligament and its effect on meniscal motion. Correlation of kinematic MR imaging and anatomic sections.

RATIONALE AND OBJECTIVES: To evaluate the effect of the transverse ligament on translation of the menisci. METHODS: Six cadaveric knees were examined by MR imaging inside a positioning device before and after transecting the transverse ligament. The knees were examined at various positions: extension, 30 degrees of flexion, 60 degrees of flexion, and full flexion. Sagittal T1-weighted spin-echo images were generated at each knee position and evaluated for statistical differences with regard to anterior-posterior meniscal excursion. RESULTS: Statistically significant differences in meniscal excursion were found before and after transsecting the transverse ligament for anterior-posterior meniscal motion of the anterior horn of the medial meniscus at 30 degrees of knee flexion. No such significant differences were found, however, at 60 degrees of flexion and full flexion in anterior-posterior meniscal excursion of the anterior or posterior horn of either meniscus before and after transsecting the transverse ligament. CONCLUSIONS: The transverse ligament has a restricting effect on anterior-posterior excursion of the anterior horn of the medial meniscus at lower degrees of knee flexion.