In-vitro ligament tension pattern in the flexed knee in passive loading

Tensions generated in selected bands of the four major ligaments of the flexed knee (40-90 degrees) have been measured in vitro when the tibia is subjected to passive anterior translation and axial rotation with and without a compressive preload. The measurements were made in 30 fresh-frozen specimens using the buckle transducer attached to the anteromedial band of the anterior cruciate ligament [ACL (am)], the posterior fibres of the posterior cruciate ligament [PCL (pf)], the superficial fibres of the medial collateral ligament [MCL (sf)], and in the total lateral collateral ligament (LCL). Particular attention was placed on the evaluation of the performance of the transducer specific to such measurements in order to minimize the errors associated with the use of this transducer. The results indicate that, among the measured ligaments, substantial tension (greater than 20 N) is generated only in the ACL (am) in tibial anterior translation up to 5 mm. The tension pattern generated in response to tibial axial rotation, however, is complex and exhibits considerable variation between specimens. In general, both the MCL (sf) and LCL are tensed at all tested flexion angles, with the tension in external rotation being significantly greater than in internal rotation. At 40 degrees of flexion, the ACL (am) bears tension mainly in internal rotation, while at 90 degrees of flexion the PCL (pf) is tensed in both senses of rotation. The response of the LCL shows marked variation among specimens; very small tension (less than 15 N) is generated in internal rotation in 48% of the specimens, and in either sense of rotation in 20% of the specimens. The tension in the ACL (am) in internal rotation is invariably greater in those specimens in which LCL tension is negligible. This correlation between increased ACL (am) function and inadequate LCL restraint appears significant in terms of ACL injury and repair.     

Fixed‐bearing medial unicompartmental knee arthroplasty restores neither the medial pivoting behavior nor the ligament forces of the intact knee in passive flexion

Medial unicompartmental knee arthroplasty (UKA) is an accepted treatment for isolated medial osteoarthritis. However, using an improper thickness for the tibial component may contribute to early failure of the prosthesis or disease progression in the unreplaced lateral compartment. Little is known of the effect of insert thickness on both knee kinematics and ligament forces. Therefore, a computational model of the tibiofemoral joint was used to determine how non‐conforming, fixed bearing medial UKA affects tibiofemoral kinematics, and tension in the medial collateral ligament (MCL) and the anterior cruciate ligament (ACL) during passive knee flexion. Fixed bearing medial UKA could not maintain the medial pivoting that occurred in the intact knee from 0° to 30° of passive flexion. Abnormal anterior–posterior (AP) translations of the femoral condyles relative to the tibia delayed coupled internal tibial rotation, which occurred in the intact knee from 0° to 30° of flexion, but occurred from 30° to 90° of flexion following UKA. Increasing or decreasing tibial insert thickness following medial UKA also failed to restore the medial pivoting behavior of the intact knee despite modulating MCL and ACL forces. Reduced AP constraint in non‐conforming medial UKA relative to the intact knee leads to abnormal condylar translations regardless of insert thickness even with intact cruciate and collateral ligaments. This finding suggests that the conformity of the medial compartment as driven by the medial meniscus and articular morphology plays an important role in controlling AP condylar translations in the intact tibiofemoral joint during passive flexion. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1868–1875, 2018.

     

The effect of section of the medial collateral ligament on force generated in the anterior cruciate ligament

Ten fresh-frozen knees from cadavera were instrumented with a specially designed transducer that measures the force that the anterior cruciate ligament exerts on its tibial attachment. Specimens were subjected to tibial torque, anterior tibial force, and varus-valgus bending moment at selected angles of flexion of the knee ranging from 0 to 45 degrees. Section of the medial collateral ligament did not change the force generated in the anterior cruciate ligament by applied varus moment. When valgus moment was applied to the knee, force increased dramatically after section of the medial collateral ligament; the increases were greatest at 45 degrees of flexion. Section of the medial collateral ligament had variable effects on the force generated in the anterior cruciate ligament during internal rotation but dramatically increased that generated during external rotation; these increases were greatest at 45 degrees. Section of the medial collateral ligament increased mean total torsional laxity by 13 degrees (at 0 degrees of flexion) to 20 degrees (at 45 degrees of flexion). Application of an anteriorly directed force to the tibia of an intact knee increased the force generated in the anterior cruciate ligament; this increase was maximum near the mid-part of the range of tibial rotation and minimum with external rotation of the tibia. Section of the medial collateral ligament did not change the force generated in the anterior cruciate ligament by straight anterior tibial pull near the mid-part of the range of tibial rotation.(ABSTRACT TRUNCATED AT 250 WORDS)     

In vivo strain patterns in the four major canine knee ligaments

Using mercury gauges, we measured strains in vivo in the four major ligaments of the canine knee joint as the tibia was loaded in valgus or varus at fixed angles of knee flexion. Free axial rotation of the tibia on the femur was allowed. Forces up to 78.4 N were applied to the tibia, producing moments of approximately 9 N-m. We found that with valgus loading, significant strains were observed in the medial collateral ligament at extension. At 45 degrees of flexion, the medial collateral, posterior cruciate, and anterior cruciate were strained. At 90 degrees of flexion, all four ligaments were strained. With varus loading, significant strains were found in the lateral collateral and anterior cruciate at extension. The lateral collateral and anterior cruciate ligaments were strained at 45 degrees of flexion. At 90 degrees of flexion, the lateral collateral, anterior cruciate, and posterior cruciate ligaments were strained. With valgus loading, the tibia rotated internally and the degree of axial rotation increased with flexion. External rotation of the tibia resulted from varus loading, and was relatively constant through the range of flexion. Thus when axial rotation is allowed, stability of the knee in response to valgus and varus loads is maintained by the cruciates as well as the collaterals, and the role of the cruciates increases with flexion and axial rotation.     

Instability of knees with ligament lesions. Cadaver studies of the anterior cruciate ligament

We studied the importance of the two parts of the anterior cruciate ligament (ACL), the medial collateral ligament (MCL), and the posterior medial capsule (PMC) to translatory and spontaneous axial rotatory instability in 15 osteoligamentous knee preparations. Instability was recorded continuously from zero to 90 degrees of flexion with application of a constant force to the tibia. Isolated cutting of the ACL caused a moderate anterior translatory movement, which increased if the MCL was also cut. Transection also of the PMC resulted in an even larger range of anterior translatory movement. Combined lesions to the MCL and the PMC and the posterolateral part of the ACL did not cause such instability provided the anteromedial part of the ACL was intact. Application of a valgus moment to specimens with injured ACL and medial structures induced a spontaneous anteromedial subluxation of the tibia in a semiflexed position. When flexion was increased to 70-80 degrees, a sudden reduction was observed.     

Instability of knees with ligament lesions: Cadaver studies of the anterior cruciate ligament

We studied the importance of the two parts of the anterior cruciate ligament (ACL), the medial collateral ligament (MCL), and the posterior medial capsule (PMC) to translatory and spontaneous axial rotatory instability in 15 osteoligamentous knee preparations. Instability was recorded continuously from zero to 90 degrees of flexion with application of a constant force to the tibia. Isolated cutting of the ACL caused a moderate anterior translatory movement, which increased if the MCL was also cut. Transection also of the PMC resulted in an even larger range of anterior translatory movement. Combined lesions to the MCL and the PMC and the posterolateral part of the ACL did not cause such instability provided the anteromedial part of the ACL was intact.

Application of a valgus moment to specimens with injured ACL and medial structures induced a spontaneous anteromedial subluxation of the tibia in a semiflexed position. When flexion was increased to 70–80 degrees, a sudden reduction was observed     

Instability of knees with ligament lesions: Cadaver studies of the anterior cruciate ligament

We studied the importance of the two parts of the anterior cruciate ligament (ACL), the medial collateral ligament (MCL), and the posterior medial capsule (PMC) to translatory and spontaneous axial rotatory instability in 15 osteoligamentous knee preparations. Instability was recorded continuously from zero to 90 degrees of flexion with application of a constant force to the tibia. Isolated cutting of the ACL caused a moderate anterior translatory movement, which increased if the MCL was also cut. Transection also of the PMC resulted in an even larger range of anterior translatory movement. Combined lesions to the MCL and the PMC and the posterolateral part of the ACL did not cause such instability provided the anteromedial part of the ACL was intact.

Application of a valgus moment to specimens with injured ACL and medial structures induced a spontaneous anteromedial subluxation of the tibia in a semiflexed position. When flexion was increased to 70-80 degrees, a sudden reduction was observed     

Ruptur des vorderen Kreuzbands

Rupture of the anterior cruciate ligament (ACL) is the most common ligamentous knee injury. The knee is stabilized by the cruciate ligaments and the collateral ligaments. The ACL originates from the inner surface of the lateral condyle of the femur, runs in an anterior medial direction and inserts at the tibial plateau in the intercondyle area. The most common injury is an indirect knee trauma, typically a joint torsion in sports. Patients often describe a snapping noise followed by hemarthrosis. Concomitant injuries are lesions of the medial collateral ligament, the medial meniscus (unhappy triad) and chondral fractures. The age peak is between 15 and 30 years with a higher incidence in females. The cardinal symptom of the ACL rupture is the giving way phenomenon. The clinical diagnosis is provided by a positive Lachman test, a positive pivot shift test and the anterior drawer test. Fractures can be excluded by X-ray examination. Magnetic resonance imaging (MRI) allows the evaluation of the internal knee structures. ACL repair is carried out by arthroscopically assisted bone-tendon-bone or semitendinosus grafting techniques. Early rehabilitation is important for a good functional outcome.     

Complex instability of the anterior knee

Complex knee instability involves the anterior cruciate ligament (ACL) and one or more major stabilizers of the knee [medial collateral ligament (MCL), lateral collateral ligament (LCL), posterior cruciate ligament (PCL)]. The medial side has a high healing potential and does not need operative treatment in most cases if ACL reconstruction is performed. Reconstruction of the medial ligament complex is indicated in gross instability of the medial meniscus fixation, dislocation of the MCL into the joint, and large dislocated bony avulsions. Injuries on the lateral side do not heal spontaneously and require acute operative treatment (first 2 weeks). Frank knee dislocations and gross multiligament injuries should be reduced acutely, and the integrity of the vascular structures must be examined closely. In a European multicenter study, operative treatment with reconstruction of both cruciate ligaments and functional rehabilitation gave better results than conservative treatment with immobilization of the joint.     

A biomechanical evaluation of the Lenox Hill knee brace

This study was conducted to determine the effectiveness of the Lenox Hill knee brace in limiting anterior translation and external rotation of the tibia in reference to the femur in normal and ligament-deficient knees. Four fresh cadaver knees were fitted with Lenox Hill knee braces according to the manufacturer's guidelines. A computer-assisted testing apparatus was constructed that allowed each knee to be tested as a function of knee flexion angle, joint load, and soft tissue integrity. Each knee served as its own control. While 45 kg of anterior force was applied to the tibia of the anterior cruciate ligament deficient knees, the Lenox Hill knee brace was able to decrease anterior translation from an average of 10 mm, to 5.7 mm, at 30 degrees of flexion when no vertical load was present. This limiting effect was lost when the medial collateral ligament was sectioned in addition to the anterior cruciate ligament or when both the medial and the lateral collateral ligaments were sectioned along with the anterior cruciate ligament. When 20 Newton-meters (Nm) of torque was applied to the femurs at 30 degrees of flexion without vertical load, the Lenox Hill knee brace limited external rotation of the tibia in all tested categories. For intact knees at 30 degrees of flexion and no vertical load, the Lenox Hill knee brace decreased external rotation from 18 degrees to 10 degrees. In the anterior cruciate ligament-sectioned knees, external rotation was decreased from an average of 20.2 degrees to 16.1 degrees. In the knees with sectioned anterior cruciate and medial collateral ligaments, the average reduction was from 21.2 degrees to 15.4 degrees.(ABSTRACT TRUNCATED AT 250 WORDS)     

Stability after medial collateral ligament release in total knee arthroplasty.

Six knees from cadavers were tested for change in stability after release of the medial collateral ligament with posterior cruciate-retaining and substituting total knee replacements. Load deformation curves of the joint were recorded in full extension and 30 degrees, 60 degrees, and 90 degrees flexion under a 10 N-m varus and valgus torque, 1.5 N-m internal and external rotational torque, and a 35 N anterior and posterior force to test stability in each knee. The intact specimen and posterior cruciate ligament-retaining total joint replacement were tested for baseline comparisons. The superficial medial collateral ligament was released, followed by release of the posterior cruciate ligament. The knee then was converted to a posterior-stabilized implant. After medial collateral ligament release, valgus laxity was statistically significantly greater at 30 degrees, 60 degrees, and 90 degrees flexion after posterior cruciate ligament sacrifice than it was when the posterior cruciate ligament was retained. The posterior-stabilizing post added little to varus and valgus stability. Small, but significant, differences were seen in internal and external rotation before and after posterior cruciate ligament sacrifice. The posterior-stabilized total knee arthroplasty was even more rotationally constrained in full extension than the knee with intact medial collateral ligament and posterior cruciate ligament.     

The role of the posterolateral and cruciate ligaments in the stability of the human knee. A biomechanical study

Injury to the posterolateral structures of the knee, including the popliteus tendon and arcuate complex, frequently results in poorly understood patterns of instability. To evaluate the static function of these tissues, we used a mechanical testing apparatus that allowed five degrees of freedom to test seventeen specimens from human cadavera at angles of flexion that ranged from zero to 90 degrees. Selective section of the lateral collateral ligament, popliteus-arcuate (deep) ligament complex, anterior cruciate ligament, and posterior cruciate ligament was performed. At all angles of flexion, the lateral collateral ligament and deep ligament complex functioned together as the principal structures preventing varus rotation and external rotation of the tibia, while the posterior cruciate ligament was the principal structure preventing posterior translation. However, at angles of flexion of 30 degrees or less, the amount of posterior translation after section of only the lateral collateral ligament and the deep structures was similar to that noted after isolated section of the posterior cruciate ligament. Isolated section of the posterior cruciate ligament did not affect varus or external rotation of the tibia at any position of flexion of the knee. When the posterior cruciate ligament was sectioned after the lateral collateral ligament and deep ligament complex had been cut, a large increase in posterior translation and varus rotation resulted at all angles of flexion. In addition, at angles of flexion of more than 30 degrees, external rotation of the tibia also increased. The application of internal tibial torque resulted in no increase in tibial rotation after isolated section of the anterior cruciate ligament or combined section of the lateral collateral ligament and deep ligament complex. However, combined section of all three structures increased internal rotation at 30 and 60 degrees of flexion. The increases in external rotation that were produced by section of the lateral collateral ligament and deep ligament complex were not changed by the addition of the section of the anterior cruciate ligament.     

关节镜下修复重建膝关节脱位合并多发韧带损伤的疗效观察

目的 探讨关节镜下重建断裂的前交叉韧带(anterior cruciate ligament,ACL)和后交叉韧带(posteriorcruciate ligament,PCL)及修复膝关节内部结构,治疗膝关节脱位合并多发韧带损伤的临床疗效.方法 2003年7月-2006年8月,收治24例膝关节脱位患者,采用关节镜下重建ACL和PCL,修复内侧副韧带(medial collateral ligament,MCL)、外侧副韧带(lateral collateralligament,LCL)和其他膝关节损伤结构.男19例,女5例;年龄20～69岁,平均42岁.均为单膝损伤,其中左膝11例,右膝13例.于伤后4h～6个月入院.ACL、PCL、MCL及LCL损伤8例,ACL、PCL及MCL损伤12例,ACL、PCL及LCL损伤4例.合并腓总神经损伤1例,内侧半月板损伤3例,外侧半月板损伤7例.评估患者术后并发症、膝关节活动范围和手术前后症状改善情况,Lysholm评分评估手术前后膝关节功能情况.结果 术后患者均获随访11～36个月,平均25个月.4例出现轻微关节僵硬,3例出现轻微关节疼痛,均未作特殊处理.11例(45.8%)运动功能恢复至伤前运动水平;13例(54.2%)显著改善,不需要辅助独立行走.24例Lachman试验、膝内外翻应力试验及前、后抽屉试验均为阴性,胫骨前后移动均<5 mm.1例腓总神经损伤者感觉运动恢复良好.Lysholm膝关节功能评分术前(41.8 ±4.3)分,术后(87.0±6.0)分:关节活动范围术前(87.5±12.5).术后(125.0 ±9.2)°术前、后比较差异均有统计学意义(P<0.05).结论 膝关节脱位后关节镜下重建ACL、PCL和修复其他膝关节结构是治疗膝关节脱位的一种有效方法.     

Differential expression of integrin subunits in canine knee ligament fibroblasts.

A method for measuring the expression of integrin subunits on the cell surface of knee ligament fibroblasts was developed with use of flow cytometry and immunofluorescence. The ligament cells exhibited uniform size and density, as shown by forward and side-scatter properties, and showed minimal nonspecific binding of isotype control antibodies compared with unstained cells. All cells expressed the alpha5 integrin subunit; lateral collateral ligament cells stained with antibody to alpha5 showed a mean fluorescence intensity 2-fold higher than that of medial collateral ligament cells, 1.5-fold higher than that of posterior cruciate ligament cells, and 3-fold higher than that of anterior cruciate ligament cells, indicating a greater expression of the alpha5 subunit by lateral collateral ligament cells than by medial collateral, posterior cruciate, and anterior cruciate ligament cells. All cells expressed the beta1 integrin subunit; the expression by posterior cruciate ligament cells was 3-fold higher than that by medial collateral ligament or lateral collateral ligament cells and 5-fold higher than that by anterior cruciate ligament cells. All cells expressed the beta3 integrin subunit; the expression by posterior cruciate ligament cells was 1.5, 3, and 4.5-fold greater than that by lateral collateral, anterior cruciate, and medial collateral ligament cells, respectively. Our data suggest there is a differential expression of integrin subunits in knee ligament fibroblasts, and this in part may explain differences in their attachment and adherence to extracellular matrix molecules.     

Active knee motion after cruciate ligament rupture. Stereoradiography

In 10 patients with an old injury of the anterior cruciate ligament, the three-dimensional movements of the knee joint were studied when the patients flexed their knees. Tibial motions were recorded using roentgen stereophotogrammetric analysis. Internal rotation and adduction of the tibia were reduced in the injured knees when compared with the intact knees; during flexion of the knee joint, the tibial intercondylar eminence occupied a more lateral and posterior position on the injured side. Our results may indicate that the knee joint is continuously exposed to abnormal stresses when the anterior cruciate ligament is torn.     

Active knee motion after cruciate ligament rupture

In 10 patients with an old injury of the anterior cruciate ligament, the three-dimensional movements of the knee joint were studied when the patients flexed their knees. Tibial motions were recorded using roentgen stereopho-togrammetric analysis. Internal rotation and adduction of the tibia were reduced in the injured knees when compared with the intact knees; during flexion of the knee joint, the tibial intercondylar eminence occupied a more lateral and posterior position on the injured side. Our results may indicate that the knee joint is continuously exposed to abnormal stresses when the anterior cruciate ligament is torn.     

Isolierte und kombinierte Kniebandverletzungen

Complex knee ligament injuries are characterized by simultaneous rupture of the anterior cruciate ligament (ACL) and/or the posterior cruciate ligament (PCL) and at least one collateral ligament. Isolated injury to the medial collateral ligament (MCL) and PCL have a high healing capacity and can be treated conservatively in many cases. Ruptures of the MCL can also be treated conservatively in complex injuries if the cruciate ligaments are reconstructed. Ruptures of the lateral structures usually need surgical reconstruction. Indications for acute surgical repair include meniscus dislocation, entrapment of collateral ligament portions in the joint, knee dislocation with severe knee instability, and displaced bony avulsions. The anatomy of the knee ligaments must be carefully respected in surgical reconstruction. Acute repair of collateral ligament injuries is possible only in the first 2 weeks after trauma. Acute arthroscopy is indicated only in combination with reconstructive surgery.     

生物可吸收挤压螺钉在膝关节韧带重建术中的应用

目的探讨生物可吸收挤压螺钉在膝关节韧带重建术中的应用和疗效。方法2002年4月~2004年8月,收治膝关节韧带损伤患者39例,其中男33例,女6例;年龄15~65岁,中位年龄25岁。单纯前交叉韧带(anterior cruciate ligament,ACL)损伤29膝,单纯后交叉韧带(posterior cruciate ligament,PCL)损伤6膝,ACL和PCL联合损伤4膝。合并内侧或外侧侧副韧带损伤3膝,合并后外侧结构损伤1膝。病程1周~8年。所有患者均行关节镜下或结合开放韧带重建术,采用自体移植物及生物可吸收螺钉固定。采用Lysholm临床评分系统对膝关节功能进行评估。结果术后34例获随访6~28个月,平均13.7个月。术后膝关节功能评分由术前43.6±13.4分,增加至术后85.4±16.3分,且差异有统计学意义(P<0.05)。患者疼痛均消失,关节稳定,无交锁和无力等症状,均恢复关节活动度,螺钉无松动。术后1例出现感染征象,3例发生局部积液和滑膜炎,经保守治疗后好转。结论在膝关节韧带重建术中,生物可吸收挤压螺钉固定疗效可靠,能有效重建韧带,恢复膝关节稳定性。     

Effects of joint load on the stiffness and laxity of ligament-deficient knees. An in vitro study of the anterior cruciate and medial collateral ligaments

We measured the effects of serial section of the medial collateral ligament and anterior cruciate ligament and of the anterior cruciate ligament and medial collateral ligament on anterior-posterior force-versus-displacement and tibial torque-versus-rotation response curves for seven fresh frozen cadaver knees at zero and 20 degrees of flexion before and after application of as much as 925 newtons of compressive load on the tibiofemoral joint. Section of the anterior cruciate ligament always increased anterior laxity in an unloaded specimen; joint load reduced this increase by a greater amount at zero degrees than at 20 degrees of flexion. Joint load was more effective in limiting anterior laxity in anterior cruciate-deficient specimens at low levels of applied anterior force; at higher levels of applied force, the effects of joint congruency were overcome and ligament restraints came into play. Section of the medial collateral ligament increased anterior laxity in an unloaded knee only for specimens in which the anterior cruciate ligament had been previously sectioned; joint load eliminated this increase at full extension but did not do so at 20 degrees of flexion. The medial collateral ligament was the more important of the two ligaments in controlling torsional laxity. Secondary section of either ligament (the other ligament having been sectioned first) produced a greater increase in laxity than did primary section of that ligament in an intact knee. Increases in torsional laxity due to primary section of either ligament were unaffected by the application of joint load. Joint load reduced increases in laxity that were due to secondary section of the medial collateral ligament.     

关节镜与MRI诊断膝关节韧带损伤的对照研究

目的对比关节镜与MRI检查膝关节韧带损伤的精准率,评价临床应用效果。方法选取膝关节韧带损伤患者52例,进行关节镜及手术前先采用MRI诊断技术进行检查,检查后的7d~6个月内进行关节镜检查或手术,将两次诊断的结果进行对比。结果 MRI诊断与关节镜及手术损伤程度的符合率:前交叉韧带为93.5%,后交叉韧带为100%,外侧副韧带为90.6%,内侧副韧带为88.5%,关节镜及手术对比诊断的符合率为93.1%。结论膝关节韧带损伤的诊断检查采用MRI诊断技术,具有精准率高、无创、安全、方便等优势,临床应用效果满意。