Essex-Lopresti损伤的生物力学研究

目的 探讨Essex-Lopresti损伤的生物力学机制,为诊治Essex-Lopresti损伤提供生物力学依据.方法 取12具成人新鲜冰冻上肢标本予以处理,先将12具标本("完整状态组")分别在旋前位、旋后位及中立位三种状态下把标本夹持固定于MTS 858生物材料试验机上进行力学测试,恒定加载100 N的压力负荷,每种状态持续30 s后减载.随后将12具标本随机分为2组,6具切除桡骨头为"切头留膜组";另6具切断前臂骨间膜(interosseous membrane,IOM)中间腱性部分为"留头切膜组".每组按上述方法进行生物力学测试.最后将所有标本均切除桡骨头并切断IOM("切头切膜组")按上述方法进行生物力学测试.结果 前臂旋转状态或单纯切断IOM对桡骨纵向位移无影响.单纯切除桡骨头或联合切断IOM和切除桡骨头增加了桡骨的纵向位移.前臂中立位时的桡骨刚度比前臂旋前位大,但比前臂旋后位小.单纯切断IOM对桡骨刚度没有影响,单纯切除桡骨头或联合切断IOM和切除桡骨头则会使桡骨刚度下降.结论 桡骨头骨折合并IOM损伤可能是Essex-Lopresti损伤产生并发症的重要原因,其中桡骨头骨折是Essex-Lopresti损伤主要原因,而IOM损伤是次要原因.桡骨头切除后IOM是维持前臂纵向稳定的主要结构.

Abstract：

Objective To study the biomechanical mechanism of Essex-Lopresti injury, and provide biomechanical basis for diagnosis and treatment of Essex-Lopresti injury. Methods Twelve fresh frozen adult upper limbs were addressed. Firstly, 12 samples ("complete state group") were loaded 100 N of a compressive force lasting 30 seconds in pronation, supination and neutral position on the mechanical testing machine. Secondly, 12 specimens were randomly divided into 2 groups. In the group named resection of radial head, the radial head was removed and interosseous membrane (IOM)was intact. In the group named the section of interosseous membrane, IOM was cut off. Finally, the radial head were removed and IOM was cut off in all specimens. The group was named as resection of radial head and IOM. Each sample was tested according to the method as described. Results The forearm rotation or single excision of the IOM had no effect on radial longitudinal displacement. Simple radial head excision or resection of the IOM and the radial head increased the vertical displacement of the radius. The radial stiffness had a gradual decline in forearm supination, neutral position and pronation. Simple excision IOM has no effect on the radial stiffness. The radial stiffness had decreased under the condition of excision of radial head or resection of the IOM and the radial head. Conclusion These in vitro measurements validate that the radial head fracture with IOM injury may be important reason for complications of the Essex-Lopresti injury. Radial head fracture play a key role for Essex-Lopresti injury and the injury of IOM is secondary cause. IOM is responsible for maintaining the vertical stability of the forearm after radial head resection.     

前臂纵向不稳定的生物力学研究

目的研究前臂纵向不稳定的生物力学机制,为临床诊断及治疗提供可靠的理论依据。方法12具新鲜冷冻尸体上肢标本制成生物力学模型,固定于MTS858型生物材料实验机上加载恒定100N的轴向负荷,测试不同解剖状态对桡骨纵向位移及前臂纵向稳定性的影响。结果单纯切断骨间膜对前臂的纵向稳定性影响甚微。切除桡骨头,前臂的纵向稳定性降低,桡骨向近端移位明显,再切断骨间膜,将使上述改变加重。结论桡骨是维持前臂纵向稳定的主要结构,前臂骨问膜是次要稳定结构。桡骨头切除后骨间膜损伤是前臂纵向不稳定产生并发症的主要原因。     

桡侧腕长伸肌肌腱重建骨间膜结合桡骨头置换恢复前臂纵向稳定性的生物力学研究

目的通过生物力学测试,评价桡侧腕长伸肌肌腱重建前臂骨间膜结合桡骨头置换恢复前臂纵向稳定性的效果。方法取10具新鲜冰冻成人前臂标本,男8具,女2具;年龄29~74岁,平均38.2岁。每个标本依次作以下处理:切除桡骨头(A组)、切除桡骨头+分离远侧尺桡关节(B组)、切除桡骨头+分离远侧尺桡关节+切除骨间膜中央束(C组)、桡侧腕长伸肌肌腱重建骨间膜(D组)、单纯桡骨头置换(E组)、桡侧腕长伸肌肌腱重建骨间膜+桡骨头置换(F组)。大体观察各组标本制备后在负荷及非负荷状态下,尺桡骨间距以及尺桡关节移位情况;行生物力学测试,记录桡骨向近端移位5 mm时施加在标本两端的负荷。结果恢复桡骨长度可以维持正常尺桡骨间距,骨间膜重建可以恢复尺桡骨间的负荷传导。生物力学测试显示,A~F组桡骨向近端移位5 mm所需负荷分别为(74.507±4.967)、(49.227±1.940)、(17.827±1.496)、(24.561±1.390)、(140.247±8.029)、(158.423±9.142)N,各组间比较差异均有统计学意义(P0.01)。结论单纯桡侧腕长伸肌肌腱重建骨间膜不能恢复前臂纵向稳定,而其联合桡骨头置换可有效重建前臂纵向稳定性。     

Essex-Lopresti损伤诊断与治疗

高能量暴力作用于前臂引起的Essex-Lopresti损伤包括桡骨头骨折、三角纤维软骨复合体损伤及前臂骨间膜撕裂三联损伤,很容易漏诊.桡骨头骨折伴有下尺桡关节疼痛、前臂旋转受限时须考虑是否存在Essex-Lopresti损伤,详细体检、X线平片、超声、MRI及术中桡骨纵向牵拉试验可帮助诊断.治疗的关键在于维持前臂纵向稳定性,因此需要通过切开复位内固定或人工桡骨头置换来恢复桡骨的正常长度.近年研究提示前臂骨间膜和三角纤维软骨复合体对维持前臂纵向稳定性也相当重要.该文就该损伤的诊断与治疗研究进展作一综述.     

前臂骨间膜的解剖及生物力学研究

目的 探讨前臂骨间膜(interosseous membrane,IOM)的解剖及生物力学特性.方法 从10个新鲜冰冻上肢标本中取出尺桡骨连同骨间膜结构,测量腱性部分的长度、宽度及厚度.测量完毕后将骨间膜腱性部分同其尺桡骨附着端一并分离,将标本的桡骨近端及尺骨远端分别用牙托粉包埋固定,标本夹持固定于MTS 858型生物材料试验机上.使用10000N力传感器进行测定,以50mm/min的速度拉伸骨间膜,直至骨间膜断裂.通过计算机采集数据描绘载荷一位移曲线,同时测定骨间膜的最大载荷和刚度.结果 (1)前臂骨间膜由三部分组成:中央腱性部分、两端膜性部分及背侧附属斜索.3个标本中未观察剑背侧附属斜索.骨间膜在前臂中立位时伸展,在前臂旋前及旋后时弯曲.(2)6个标本发生骨间膜腱性部分撕裂,最大载荷为(1021.50+250.13)N,刚度为(138.24±24.29)N/mm,骨间膜的拉伸长度为(9.77+1.77)mm;4个标本在腱性部分撕裂之前发生尺骨固定端骨折,最大载荷为(744.40+109.85)N,刚度为(151.17+30.68)N/mm,骨间膜的拉伸长度为(6.51+0.51)mm.结论 前臂骨间膜是尺桡骨之间具有韧带性质的结构,对维持前臂的纵向稳定至关重要.其解剖学及生物力学数据可以作为评估前臂骨间膜重建方法的客观标准.     

前臂纵向分离的研究进展

前臂纵向分离(longitudinal radioulnar dissociation,LRUD)是指腕部受到轴向暴力,造成桡骨头/颈骨折或脱位合并骨间膜撕裂和下尺桡关节分离的复杂联合损伤,引起前臂纵向不稳定。生物力学研究表明在切除桡骨小头情况下,单纯重建骨间膜仅能减轻桡骨向近侧移位,而恢复LRUD前臂的纵向稳定性需要骨间膜重建与桡骨头金属假体置换联合。LRUD误诊和漏诊率高,MRI和B超是早期检查骨间膜损伤的有效方法。目前治疗强调修复LRUD的所有损伤结构而恢复前臂稳定性,即修复或重建桡骨头、矫正下尺桡关节,同时重建骨间膜。治疗成功与否取决于能否早期诊断。     

前臂骨间膜的磁共振成像及其动态变化

前臂骨间膜（interosseous membrane,IOM）损伤常作为前臂骨折的伴随损伤而出现（如Essex—Lopresti骨折、盖氏骨折和桡骨远端骨折等）。由于常规平片检查无法显示骨间膜,因而漏诊和误诊的病例较多,患者多出现长期腕部疼痛、握持力量减弱、前臂旋转功能受限及肘关节活动障碍等严重并发症。IOM对于维护前臂的纵向稳定和旋转功能至关重要。Hotchkiss等研究指出,桡骨头切除后前臂纵向稳定强度的71％由IOM中央区维持。目前运用磁共振成像（MRI）对骨间膜进行研究已有报道,但在临床应用方面尚无太多经验。     

前臂完整性与尺桡肌的生物力学变化

目的：从生物力学角度探讨桡骨头切除后远期并发症的病因。方法：用新鲜解冻尸体上肢,在尺桡骨表面粘巾应变片,安装百分表。在生物力学试验机上连续加载和卸载,测试不同体位,不同解部状态各点应变值及纵轴位移。结果：应变值与载荷、体位及解剖状态有关。体位及单纯骨间膜切断对尺柳骨间纵轴稳定性影响甚微。切除桡骨小头,尺桡骨间稳定性降低,再切断骨间膜,将使以上改变加重。结论：桡骨小头切除后肱尺关节载荷紊乱及纵轴失稳     

Essex-Lopresti损伤治疗

EssexLopresti损伤包括桡骨头骨折、尺桡远侧关节分离和骨间膜撕裂,导致前臂活动障碍和纵向不稳定。Essex-Lopresti损伤发病率极低,容易漏诊而未予处置,使患肢功能受损;治疗不充分也会使前臂急性不稳定变成更为复杂的陈旧性纵向不稳定。及时诊断有赖于对此类损伤的充分了解和详尽的物理、超声及放射线检查。急性期损伤治疗旨在防止桡骨向近侧移位,需要正确处理桡骨头骨折,避免桡骨头切除,修复三角纤维软骨复合体,损伤的骨间膜重建与否尚有争议;陈旧性损伤处理的中心环节是重建完整的稳定结构,恢复尺桡远侧关节高度,最终恢复前臂尺桡骨之间的正常关系,消除纵向不稳定,方法包括人工桡骨头置换、尺骨截骨短缩、骨间膜中央束重建和三角纤维软骨复合体修复。     

前臂完整性与尺桡骨的生物力学变化

目的：从生物力学角度探讨桡骨头切除后远期并发症的病因。方法：用新鲜解冻尸体上肢,在尺桡骨表面粘贴应变片,安装百分表。在生物力学试验机上连续加载和卸载,测试不同体位,不同解剖状态各点应变值及纵轴位移。结果：应变值与载荷、体位及解剖状态有关。体位及单纯骨间膜切断对尺桡骨间纵轴稳定性影响甚微。切除桡骨小头,尺骨应力增加,尺桡骨间稳定性降低,再切断骨间膜,将使以上改变加重。结论：桡骨小头切除后肱尺关节载荷紊乱及纵轴失稳是多种术后并发症的原因。     

Graft reconstruction of the interosseous membrane in conjunction with metallic radial head replacement: a cadaveric study

PURPOSE: Longitudinal radioulnar dissociation (Essex-Lopresti injury) occurs when traumatic axial loading through the wrist disrupts the interosseous membrane (IOM) of the forearm and fractures the radial head. Proximal migration of the radius results in an ulnar-positive wrist, which can lead to painful ulnar-sided wrist degeneration and distal radioulnar joint instability. The purpose of this study was to measure the ability of an IOM reconstruction used in combination with a metal prosthetic radial head implant to reduce distal ulnar forces in a cadaveric model. The effects of varying the initial graft pretension on distal ulnar force were also studied. METHODS: Twelve fresh frozen and thawed cadaveric forearms had a miniature load cell installed to record force in the distal ulna as the wrist was loaded axially to 134 N of compression force in neutral rotation. Intact forearms were tested first with the elbow in valgus and varus alignments. Loading tests were repeated after (1) insertion of a metal radial head implant that restored radius anatomic length, (2) excision of the IOM (with a radial head implant), and (3) reconstruction of the IOM using a palmaris longus tendon autograft (with a radial head implant). The implant then was removed and loading tests were repeated using 3 levels of initial graft pretension. RESULTS: Mean distal ulnar forces with an intact forearm were 23% of applied wrist force in the varus alignment and 12% in the valgus alignment. Mean force levels after insertion of the implant were 18% (varus) and 13% (valgus); these were not significantly different from corresponding values for the intact forearm. Mean force levels after section of the IOM were 30% (varus) and 14% (valgus); these were not significantly different from corresponding values for the intact forearm (varus and valgus) but the mean for varus was significantly greater than the corresponding value with an implant. After IOM reconstruction with a palmaris longus tendon tensioned to 22 N mean distal ulnar forces were 8% (varus) and 7% (valgus); these means were significantly less than the corresponding values for all prior test conditions. With the radial head removed increasing the level of graft pretension reduced significantly mean distal ulnar force. CONCLUSIONS: With the IOM resected insertion of a metal radial head implant alone did not reduce distal ulnar forces to intact forearm levels. When an IOM reconstruction was performed in combination with the implant mean distal ulnar force was reduced significantly to a level below that for the intact forearm. Applying pretension to the graft displaced the radius distally thereby making the wrist more ulnar negative and reducing distal ulnar force. Our results suggest that an IOM reconstruction used in combination with a metal radial head implant theoretically could help reduce distal ulnar impaction in an Essex-Lopresti injury.     

The effects of partial and total interosseous membrane transection on load sharing in the cadaver forearm.

This study was performed to examine the effects of partial and total transection of the interosseous membrane (IOM) on load transfer in the forearm. Twenty fresh frozen forearms were instrumented with custom designed load cells placed in the proximal radius and distal ulna. Simultaneous measurements of load cell forces, radial head displacement relative to the capitellum, and local tension within the central band of the IOM were made as the wrist was loaded to 134 N with the forearm at 90 degrees of elbow flexion and in neutral pronation supination. For valgus elbow alignment (radial head contacting the capitellum), mean force carried by the distal ulna was 7.1% of the applied wrist force and mean force transferred from radius to ulna through the IOM was 4.4%. For varus elbow alignment (mean 2.0 mm gap between the radial head and capitellum), mean distal ulna force was 28% and mean IOM force was 51%. Section of the proximal and distal one-thirds of the IOM had no significant effect upon mean distal ulnar force or mean IOM force. Total IOM section significantly increased mean distal ulnar force for varus elbow alignment in all wrist positions tested. The mean level of applied wrist force necessary to close the varus gap (89 N) decreased significantly after both partial IOM section (71 N) and total IOM section (25 N). The IOM became loaded only when the radius displaced proximally relative to the ulna, closing the gap between the radius and capitellum. As the radius displaced proximally, the wrist becomes increasingly ulnar positive, which in turn leads to direct loading of the distal ulna. This shift of force to the distal ulna could present clinically as ulnar sided wrist pain or as ulnar impaction after IOM injury.     

Ultrasonography for the evaluation of forearm interosseous membrane disruption in a cadaver model

Recognition of interosseous membrane disruption associated with radial head injury and Essex-Lopresti injury is important, especially if radial head excision is contemplated. Because a widely accepted method to diagnose interosseous membrane disruption does not exist, we evaluated the accuracy of ultrasonography to diagnose this injury in a cadaver model. Nine pairs of cadaver forearms were randomized into 2 groups. The central third of the interosseous membrane of forearms of group 1 was cut, whereas it was visualized but not cut in group 2. A dynamic ultrasound examination was performed to determine interosseous membrane integrity, and static images were made. The static images were evaluated by 2 other radiologists and interpretations were recorded. One radiologist incorrectly interpreted 1 pair of forearms; the other 2 radiologists were 100% accurate. The accuracy of ultrasonography in detecting interosseous injuries was 96% with our methods.     

Forearm and elbow injury: the influence of rotational position

BACKGROUND: The purpose of this study was to develop an axial loading forearm fracture model and to determine the influence of forearm rotation on the fracture pattern. METHODS: Twenty-six cadaveric arms were thawed in saline solution. Pressure-sensitive film was sealed and was placed through a lateral arthrotomy into the radiocapitellar joint. The arm was potted at the proximal part of the humerus with the elbow in extension. Rotational range of motion was measured with use of a goniometer starting from a supinated position (0 degrees ). Specimens were placed in a vertical position at various angles of forearm rotation, and a 27-kg mass was raised to 90 cm and was dropped onto the distal part of the radius. The pressure film was removed and was analyzed to determine the radiocapitellar joint contact area following impact. Each arm was dissected, and the injury pattern was assessed. RESULTS: Both-bone forearm fractures (proximal radial fractures with concomitant distal ulnar fractures) occurred at 5 degrees +/- 2.6 degrees of rotation, isolated radial head fractures occurred at 44.4 degrees +/- 5.2 degrees of rotation, and Essex-Lopresti fractures (radial head fractures with tearing of the interosseous membrane) occurred at 70 degrees +/- 25.2 degrees of rotation. The distribution of Essex-Lopresti and radial head fractures was significantly different at a cutpoint of 54 degrees of forearm rotation (p = 0.009), and the distribution of radial head fractures and both-bone forearm fractures was significantly different at a cutpoint of 10 degrees of forearm rotation (p = 0.001). The percent contact area of the radial head varied with the injury pattern (p = 0.029). Marginal radial head fractures occurred at 46.7 degrees +/- 6.6 degrees of rotation with a contact area of 30.9% +/- 8.6%, while comminuted radial head fractures occurred at 74.4 degrees +/- 27.2 degrees of rotation with a contact area of 53.9% +/- 8.3%. CONCLUSION: The amount of forearm rotation at the time of axial load impact directly influenced the injury pattern. Furthermore, the radial head contact area and the fracture severity increased in pronation compared with supination.     

Radius pull test: predictor of longitudinal forearm instability

BACKGROUND: Longitudinal instability of the forearm (the Essex-Lopresti lesion) following radial head excision may be difficult to detect. This cadaveric study examines a stress test that can be performed in the operating room to identify injury to the ligamentous structures of the forearm. METHODS: Twelve cadaveric upper extremities were randomized into two groups and underwent radial head resection. Group 1 underwent sequential transection of the triangular fibrocartilage complex and the interosseous membrane. Group 2 underwent sequential transection of the interosseous membrane and the triangular fibrocartilage complex. Ulnar variance and radial migration were examined with use of fluoroscopy of the wrist before, during, and after the application of a 9.1-kg load via longitudinal traction on the proximal part of the radius. RESULTS: Group 1 demonstrated no significant changes in proximal radial migration with load (compared with the findings after radial head resection alone) after transection of the triangular fibrocartilage complex. However, Group 2 demonstrated significant changes in proximal radial migration with load after transection of the interosseous membrane (p = 0.03; median, 3.5 mm). In both groups, transection of both the triangular fibrocartilage complex and the interosseous membrane resulted in significant changes in proximal radial migration with load (p = 0.001; median, 9.5 mm). When the load was removed, specimens were ulnar positive (median, 3.0 mm), with no specimen returning to the preload position of ulnar variance (p = 0.001). CONCLUSION: After radial head resection, 3 mm of proximal radial migration with longitudinal traction indicated disruption of the interosseous membrane. In all specimens, proximal radial migration of > or =6 mm with load indicated gross longitudinal instability with disruption of all ligamentous structures of the forearm.     

Anatomical and biomechanical study on the interosseous membrane of the cadaveric forearm

Objective

To study the anatomical and biomechanical features of the interosseous membrane (IOM) of the cadaveric forearm.

Methods

Ten radius-IOM-ulna structures were harvested from fresh-frozen cadavers to measure the length, width and thickness of the tendinous portion of IOM. Then, the tendinous portion was isolated along with the ulnar and radial ends to which the tendon attached after measurement. The proximal portion of the radius and the distal portion of the ulna were embedded and fixed in the dental base acrylic resin powder. The embedded specimen was clamped and fixed by the MTS 858 test machine using a 10 000 N load cell for the entire tensile test. IOM was stretched at a speed of 50 mm/min until it was ruptured. The load-displacement curve was depicted with a computer and the maximum load and stiffness were recorded at the same time.

Results

The IOM of the forearm was composed of three portions: central tendinous tissue, membranous tissue and dorsal affiliated oblique cord. IOM was stretched at a neutral position, and flexed at pronation and supination positions. The tendinous portion of IOM was lacerated in 6 specimens when the point of the maximum load reached to 1021.50 N ± 250.13 N, the stiffness to 138.24 N/m±24.29 N/m, and the length of stretch to 9.77 mm±1.77 mm. Fracture occurred at the fixed end of the ulna before laceration of the tendinous portion in 4 specimens when the maximum load was 744.40 N ± 109.85 N, the stiffness was 151.17 N/m±30.68 N/m, and the length of the stretch was 6.51 mm±0.51 mm.

Conclusions

The IOM of the forearm is a structure having ligamentous characteristics between the radius and the ulna. It is very important for maintenance of the longitudinal stability of the forearm. The anatomical and biome-chanical data can be used as an objective criterion for evaluating the reconstructive method of IOM of the forearm.     

The Essex-Lopresti lesion

The Essex-Lopresti lesion represents a severe injury of the forearm unit. In the 1940s, it’s pathology and consequences have already been mentioned by several authors. Over the course of time, the pathophysiology of the lesion was displayed in more detail. Therefore, an intensive analysis of the involved anatomic structures was done. The interosseous membrane was shown to play a major role in stabilising the forearm unit, in the situation of a fractured radial head, which is the primary stabiliser of the longitudinal forearm stability. Moreover, biomechanical analyses showed a relevant attribution of the distal radio-ulnar joint to the forearm stability. If, in the case of a full-blown Essex-Lopresti lesion, the radial head, the interosseous membrane and the distal radio-ulnar joint are injured, proximalisation of the radius will take place and will come along with secondary symptoms at the elbow joint and the wrist. According to actual studies, the lesion seems to occur more often than realised up to now. Thus, to avoid missing the complex injury, subtle clinical diagnosis combined with adequate imaging has to be undertaken. If the lesion is confirmed, several operative treatment options are available, yet not proofed to be sufficient.     

The role of the distal radioulnar ligaments, interosseous membrane, and joint capsule in distal radioulnar joint stability

The individual contribution of the distal radioulnar ligaments to dorsal and palmar translational stability during forearm rotation remains controversial. Furthermore, the role of the distal radioulnar joint capsule as a restraint and contributor to stability has not been investigated. A biomechanical study was performed in 11 fresh cadaver specimens to simultaneously measure dorsal and palmar radioulnar ligament tension. Joint rotation and radial translation were measured after sequential excision of the disk, interosseous membrane, joint capsule, and radioulnar ligaments. Results confirmed that the dorsal ligament tightens during pronation while the palmar ligament becomes progressively lax; the converse occurred during supination. Translational stability remained intact at all positions throughout the sectioning sequence until one of the radioulnar ligaments was sectioned. The most significant increases in translation occurred after sectioning the dorsal radioulnar ligament in pronation and after sectioning the palmar radioulnar ligament in supination. Forearm rotation increased significantly after excising either hemicapsule.     

Ultrasonography for the interosseous membrane of the forearm.

The ability to improve the technique for an accurate clinical diagnosis of the injury of interosseous membrane of the forearm (IOM) associated with forearm fractures and dislocations is important for its treatment and prognosis. Ultrasound examination of the IOM in 46 forearms from 18 normal volunteers, five patients with restricted forearm pronation and supination, and two preoperative cases was performed to determine the usefulness and reproductivity of this examination. The intact IOM was observed as a continuous, slightly convex anteriorly and hyperechoic structure between the radius and ulna with both transverse and longitudinal views. IOMs with histories of forearm injuries were distinguished by the findings, which demonstrated a loss of continuity and were seen as hypoechoic traces from the others. This study confirmed that it is possible to trace the entire IOM and to detect differences between intact and disrupted IOMs with transverse and longitudinal views.