Three-dimensional motion analysis of clinical stress tests for anterior knee subluxations

The three rotations and three translations that comprise total knee motion were simultaneously measured in cadaveric knees during the commonly employed clinical tests for anterior cruciate injury. A second study determined the three-dimensional motions that occurred when known forces and moments were applied. A total of eight whole lower limbs were studied. A 6 degree-of-freedom instrumented linkage (3-D electrogoniometer), rigidly mounted to the tibia and femur, was used. The ligaments sectioned included the lateral extraarticular restraints (iliotibial band, lateral capsule) and the anterior cruciate ligament, both separately and in combination.

After sectioning the anterior cruciate ligament alone, anterior displacement of both the medial and lateral tibial condyles increased markedly during the flexion rotation drawer and pivot shift tests. At 30° knee flexion, total anterior-posterior displacement increased 100 percent, but internal-external tibial rotation increased only 15 percent.

In all the anterior displacement type of clinical tests (including Lachman's test), there was not a true rigid coupling of knee motions because the examiner controlled the amount of internal tibial rotation and anterior tibial translation. After anterior cruciate sectioning alone, both the lateral and medial tibial condyles displaced anteriorly. Sectioning the medial structures caused additional anterior translation of the medial and lateral tibial condyles.

We measured many different combinations of motions that depend on the ligament and capsular structures injured, the clinical test used, and how the clinician performed the test. Differing types of anterior subluxation require that the separate subluxations of the medial and lateral tibial condyles be determined during each stress test.     

Three-dimensional analysis of neck motion. A clinical method

A clinical method is described for simultaneous recording of neck motion in three different planes using electrogoniometric equipment. Results correlated with those reported in the literature regarding separate examinations of the motion range in the separate planes. Correlation with conventional gravity goniometer was good as to flexion-extension and lateral flexion, whereas, for rotation, a compass goniometer showed poor correlation and, also, unsatisfactory reproducibility. The electrogoniometric recordings showed good correlation with radiographically determined flexion-extension occiput-C7 as well as lateral flexion C1-T1. Graphical recordings made in the three different planes demonstrated in detail the different movements that contribute to the complex motion pattern of the neck. This three-dimensional motion analysis affords a more objective functional evaluation of common neck disorders that may supplement radiographic examination.     

新型膝关节运动分析系统的研制及临床应用

运动分析技术在临床步态分析以及肌骨系统的辅助诊断,功能评估和康复领域已有较多应用。而新型的Opti_Knee膝关节运动分析系统是一种临床操作简便,可移动便携设计,在体无创动态评估膝关节6自由度运动的分析系统,近年来也开始应用于骨科、运动医学、康复等领域。本文从技术原理和临床应用角度出发,对国内外近6年的相关文献进行了系统归纳和总结,回顾了该系统的起源与发展、结构与原理,归纳了在健康人群膝关节功能评估、膝关节运动损伤因素和膝关节疾病临床诊治方面的应用和成果,如步态特征观察、前交叉韧带损伤辅助诊断、膝骨关节炎手术疗效评价和科学指导康复等,总结了应用中遇到的问题和下一步需要攻克的难题,展望了该系统在运动损伤防治领域应用的未来。     

Three-dimensional knee motion before and after high tibial osteotomy for medial knee osteoarthritis

Background High tibial osteotomy (HTO) is an established surgical option for treating medial knee osteoarthritis. HTO moves the mechanical load on the knee joint from the medial compartment to the lateral compartment by changing the leg alignment, but the effects of the operation remain unclear. The purpose of this study was to evaluate the change in three-dimensional knee motion before and after HTO, focusing on lateral thrust and screw home movement, and to investigate the relationship between the change in knee motion and the clinical results. Methods A series of 19 patients with medial knee osteoarthritis who had undergone HTO were evaluated. We performed a clinical assessment, radiological evaluation, and motion analysis at 2.4 years postoperatively. The clinical assessment was performed using the Japanese Orthopaedic Association knee score. Results The score was significantly improved in all patients after operation. Motion analysis revealed that lateral thrust, which was observed in 18 of the 20 knees before operation, was reduced to 7 knees after operation. Regarding active terminal extension of the knee, three patterns of rotational movement were observed before operation: screw home movement (external rotation), reverse screw home movement (internal rotation), and no rotation. By contrast, after operation, only reverse screw home movement and no rotation were observed; the screw home movement disappeared in all patients. In the knees with reverse screw home movement after operation, the preoperative score was significantly lower than those in the knees with no rotation after operation. Conclusions Kinetically, HTO was useful for suppressing lateral thrust in medial knee osteoarthritis, although the rotational movement of the knee joint was unchanged.     

Three-dimensional instability of the anterior cruciate deficient knee

Using roentgen stereophotogrammetry we have recorded the three-dimensional movements of the knee during an anteroposterior laxity test in 36 patients with torn anterior cruciate ligaments and in three cadaver knees. At 30 degrees of knee flexion and before loads were applied the tibia occupied a more laterally rotated position if the anterior cruciate ligament had been injured. When the tibia was pulled anteriorly knees with cruciate deficiency rotated more laterally and were more abducted than normal knees. Posterior traction induced lateral rotation in the injured knee and medial rotation in the intact one. Precise knowledge of the three-dimensional instability of the anterior cruciate deficient knee may be important when the laxity is evaluated only in relation to one of the three cardinal axes.     

Three-dimensional motion analysis with Synex

The authors present a new implant for vertebral body replacement in the thoracic and lumbar spine. Synex is a titanium implant designated for reconstruction of the anterior column in injury, post-traumatic kyphosis or tumour of the thoracolumbar spine and must be supplemented by a stabilizing implant. After positioning, the implant is distracted in situ, thus ensuring best contact with adjacent end-plates and three-dimensional (3D) stability, and minimizing the possibility of secondary dislocation or loss of correction. We compared the effectiveness of the Synex implant with that of the “Harms cage” (MOSS) in combination with two alternative stabilizing instrumentations: the USS and Ventrofix. In a 3D spinal loading simulator, we determined the bisegmental (T12–L2) neutral zone (NZ), elastic zone (EZ), and range of motion (ROM) of 12 human cadaveric spines. After corpectomy of L1, we tested the four possible combinations of stabilizing instrumentation and vertebral replacement implant: USS/Synex, USS/MOSS, Ventrofix/Synex, Ventrofix/MOSS. We analysed the differences between each of the instrumentations as well as differences compared to the intact spine. Comparing the two stabilizing implants, a significantly higher stability was achieved with the USS for flexion, extension, and lateral bending, regardless of whether Synex or MOSS was used as vertebral body replacement. No differences were observed for axial rotation. In addition, no implant combination was able to restore the rotational stability of the intact spine. Comparing the vertebral body replacing implants, significantly higher stability was noted with Synex in combination with USS for extension, lateral bending, and axial rotation. No differences between Synex and MOSS were observed in combination with Ventrofix. Posterior fixation was found to offer superior stability compared to anterior fixation. Synex was at least comparable to MOSS for suspensory replacement of the vertebral body in the thoracolumbar spine. The increased biomechanical stability demonstrated for Synex suggests that a more rigid construction would also be achieved in vivo. When using MOSS in combination with posterior stabilization, the induction of intervertebral compression via the posterior fixator is recommended. This surgical step was not necessary with Synex. Received: 25 January 2000 Revised: 5 May 2000 Accepted: 22 May 2000     

膝关节三维有限元分析

有限元分析是在工程科学技术领域广泛应用的数学物理方法,是解决复杂工程学问题的必备工具之一.将有限元分析应用于人体生物力学研究,已显示出极大的优越性.通常的力学试验手段基本上不直接应用于人体,其试验结果并不十分准确;有限元分析则可通过对实验条件的控制,更准确地模拟体内的力学情况.对人体力学行为进行有限元数值模拟已成为深化对人体认识的一种有效手段.该文对膝关节三维有限元分析的近期研究进展进行综述,讨论在临床应用中的实际意义,并总结目前有限元分析在膝关节生物力学研究中存在的不足.     

Characterizing the motion of total knee replacements in laboratory tests

The purposes of determining the motion of a total knee replacement in vitro are to characterize the stability and laxity characteristics and to predict the kinematic behavior of the total knee replacement when implanted. With this information, different total knee replacement designs can be compared, the stability of the implanted knee replacement with and without the retention of ligaments can be assessed, and tests can be formulated to measure the wear and deformation of the materials, the strength of the components, and the fixation to the bone. Initially, different ways are described for characterizing the kinematics of the natural knee. We propose a rationale for the kinematic testing of total knee replacements in vitro using mechanical tests. One of the key questions is whether there is an objective method of measuring the kinematics of a total knee replacement in vitro, which will relate to or predict its behavior in vivo.     

Three-dimensional analysis of image-free navigation system for total knee arthroplasty

Malalignment causes abnormal forces that may lead to loosening after knee replacement. Whether a computer-assisted technique can improve the precision of implant positioning guaranteeing good long-term results in total knee arthroplasty, this is a matter of discussion. The authors evaluate the alignment accuracy of 20 primary total knee arthroplasties, performed using an image-free computer navigation systems, with standardized CT protocol and three-dimensional digital model reconstruction. The results of this study demonstrate that the image-free navigation system is able to improve accuracy in axial limb alignment and positioning of the components in the majority of cases; moreover, the difference between the mean mechanical axis value of the navigation system (179.7° ± 1.7°) and the median mean value obtained during the post-operative evaluation (180.3° ± 1.9°) is not statistically significant (P = 0.28).     

Association of KT-1000 measurements with clinical tests of knee stability 1 year following anterior cruciate ligament reconstruction.

STUDY DESIGN: Prospective, observational study. OBJECTIVES: To determine the association between KT-1000 measurements with an anterior translation force of 89 N and other measures of outcome (the Tegner activity score, the modified Lysholm score, subjective rating of instability, Lachman test, and pivot-shift test) 1 year following anterior cruciate ligament (ACL) reconstruction. BACKGROUND: Health care professionals often use the side-to-side difference measured with the KT-1000 arthrometer to determine ACL integrity during passive motion. It has been postulated that a 5-mm or greater difference between impaired and nonimpaired knees represents a procedural failure. METHODS AND MEASURES: Ninety patients (46 men, 44 women) with a mean age of 30 +/- 8 years were examined 1 year after surgery. Patients were classified in 1 of 3 groups depending on the amount of laxity between the impaired knee and the nonimpaired knee. Seventy percent of the subjects had a side-to-side difference less than or equal to 3 mm (tight), 13% had a difference of between 3 and 5 mm (moderate), and 17% had a difference greater than or equal to 5 mm (loose) on examination using the KT-1000. RESULTS: Mean Lysholm and Tegner scores did not differ significantly among groups. Side-to-side differences in KT-1000 measurements at 89 N were not associated with the Lysholm score (r = -0.09) or Tegner score (r = 0.02). Lachman tests were related to involved-knee KT-1000 measurements (r = 0.39) but not to side-to-side differences in KT-1000 measurements (r = 0.15). Similarly, pivot-shift tests were related to involved-knee KT-1000 measurements (r = 0.26) but not to side-to-side differences (r = -0.08). CONCLUSIONS: These results suggest that side-to-side KT-1000 measurements obtained with an anterior translation force of 89 N should not be used in isolation to determine ACL reconstruction success or failure 1 year following surgery.     

全膝关节置换术后膝关节线改变与膝前痛的相关性

目的 探讨全膝关节置换术后膝关节线改变与膝前痛的相关性.方法 回顾性分析2008年1月至2010年12月因膝关节骨关节炎行初次全膝关节置换的76例患者的病例资料,男11例,女65例;年龄47～83岁,平均(68.88±7.61)岁.术中应用PFC后稳定型固定平台膝关节假体.术后每12个月定期门诊随访一次.根据Figgie膝关节线测量方法对术前及随访时的关节线进行测量,并计算术前、术后关节线的变化.关节线升高为正值,关节线降低为负值.采用Feller评分法评估术前及随访时的髌骨功能.评估术后24个月的关节线改变水平与Feller髌骨评分的相关性.结果 关节线改变-6.8～10.44 mm,平均(2.69±3.31) mm.随膝关节线升高,Feller髌骨评分呈下降趋势;关节线改变值与Feller髌骨评分呈负相关(r=-0.763,P=0.000).随关节线降低,Feller髌骨评分呈下降趋势;关节线改变值与髌骨评分呈正相关(r=0.914,P=0.000).术后12、24个月关节线改变4 mm以内的患者(55例)Feller髌骨评分均高于关节线改变大于4 mm的患者(21例),差异有统计学意义(t=12.648,P=0.000;t=11.775,P=0.000).结论 对后稳定型固定平台膝关节假体,关节线改变与膝前痛具有相关性,保持关节线变化在±4 mm以内有利于恢复膝关节功能.     

Interesting clinical presentation of anterior knee pain causing diagnostic dilemma

A diverse variety of lesions may occasionally occur in the patella. In this case report, we are presenting an interesting case of anterior knee pain in middle aged gentleman. Initial investigations including Magnetic Resonance Imaging not showed any abnormality. Due to prolonged continued pain he had bone scan and MRI, which confirmed the diagnosis of Brodie’s abscess. We are presenting this case of Brodie’s abscess of the patella causing diagnostic dilemma because of its rarity.     

膝关节血供三维可视化研究及其临床意义

目的了解膝关节血管分布和血供模式，为微创化全膝关节置换术入路的选择提供应用解剖学基础。方法1例新鲜成人下肢标本动脉血管改良显影剂灌注后，薄层CT扫描，Mimics10．0软件重建下肢骨与血管；对标本解剖观测。分析膝关节局部血管走行及分布特点，了解各知名血管与全膝关节置换手术入路的关系。结果血管显影清晰，伪影少。重建了膝关节的骨性结构和血管的三维（3D）模型。股动脉、胭动脉、胫前动脉和股深动脉等血管的分支在膝部交通、吻合，形成可分为髌网、股骨外侧髁和内侧髁网、髌下网等的膝关节血管网。膝关节置换术，经股肌下／经股肌入路时肌肉关节支是防止神经、股动脉损伤的安全标志，应尽可能保留；膝下外侧动脉应注意保护。结论结合CT／MRI、计算机图像处理、3D重建技术，可以直观立体再现膝关节结构及其血供特点，为临床手术入路选择提供直观的参考。     

A biomechanical evaluation of clinical stress tests for syndesmotic ankle instability

Displacement transducers were placed across the anterior and posterior tibiofibular ligaments of 17 fresh cadaver (78.4 +/- 6.7 years old at death) lower extremities. Displacements induced by various clinical tests (squeeze, fibula translation, Cotton, external rotation, and anterior drawer) were measured with the ankle ligaments intact and after sequential sectioning of the anterior tibiofibular ligament, anterior deltoid ligament, and posterior tibiofibular ligament. None of the syndesmotic stress tests could distinguish which ligaments were sectioned. Furthermore, the small displacements measured during the stress tests (with the exception of the external rotation test) suggest it is unlikely that the displacement induced in injured syndesmoses can be clinically differentiated from normal syndesmoses. Therefore, pain, rather than increased displacement, should be considered the outcome measure of these tests.     

Measurement of anterior instability of the knee. A new apparatus for clinical testing

We have developed an apparatus to measure the anteroposterior stability of the knee to forces of up to 250 N, applied at 20 degrees of flexion. We measured anterior laxity at 200 N, anterior stiffness at 50 N and total laxity at +/- 200 N. A study of cadaveric knees revealed that the soft tissues surrounding the bones had a significant influence on the force-displacement curve, and emphasised that differences between injured and normal pairs of knees are much more important than the absolute values of the parameters. In 61 normal volunteers we found no significant left to right differences in anterior laxity at 200 N and anterior stiffness at 50 N. In 92 patients with unilateral anterior cruciate deficiency there were significant differences (p less than 0.0005) in anterior laxity, anterior stiffness and total laxity, the injured-normal differences averaging 6.7 mm, 1.3 N/mm, and 8.1 mm respectively.     

Three-dimensional knee joint movements during a step-up: Evaluation after anterior cruciate ligament rupture

The three-dimensional motions of the knee were analysed during closed kinetic chain knee extension in 13 patients with unilateral chronic injury of the anterior cruciate ligament. The patients ascended a platform, and serial stereophotogrammetric roentgenograms were exposed from about 100° of flexion to full extension. From a position of about 100° of knee flexion and 20° of internal rotation, the tibia rotated externally during the extension. Almost no tibial adduction or abduction was observed. The tibial intercondylar eminence translated laterally, distally, and anteriorly relative to the femur. In knees with absence of the anterior cruciate ligament, the intercondylar eminence had a more posterior position compared with the contralateral normal knees. The proximal tibia was used as a fixed reference segment to evaluate the anteroposterior translations of a central point in the femoral condyles. The femoral point was more anteriorly displaced in the injured than in the contralateral knees. This difference might reflect increased activity of the hamstrings in the injured knees, because it was most pronounced at 80° of flexion and decreased with increasing extension. In the sagittal plane, the mean helical axis was positioned close to the femoral insertion of the ligament at 80° of flexion and was displaced distally and anteriorly during extension. In the frontal plane, the axis had a transverse direction at 80° of flexion. At close to full extension, the axis was positioned distally in the lateral condyle and proximally in the medial condyle. In the horizontal plane, the helical axes ran slightly more anteriorly in the medial than in the lateral femoral condyle but changed inclination at close to full extension and became almost parallel to the transverse axis.