Ligamentous stabilizers against posterolateral rotatory instability of the elbow.

BACKGROUND: The lateral ulnar collateral ligament, the entire lateral collateral ligament complex, and the overlying extensor muscles have all been suggested as key stabilizers against posterolateral rotatory instability of the elbow. The purpose of this investigation was to determine whether either an intact radial collateral ligament alone or an intact lateral ulnar collateral ligament alone is sufficient to prevent posterolateral rotatory instability when the annular ligament is intact. METHODS: Sequential sectioning of the radial collateral and lateral ulnar collateral ligaments was performed in twelve fresh-frozen cadaveric upper extremities. At each stage of the sectioning protocol, a pivot shift test was performed with the arm in a vertical position. Passive elbow flexion was performed with the forearm maintained in either pronation or supination and the arm in the varus and valgus gravity-loaded orientations. An electromagnetic tracking device was used to quantify the internal-external rotation and varus-valgus angulation of the ulna with respect to the humerus. RESULTS: Compared with the intact elbow, no differences in the magnitude of internal-external rotation or maximum varus-valgus laxity of the ulna were detected with only the radial collateral or lateral ulnar collateral ligament intact (p > 0.05). However, once the entire lateral collateral ligament was transected, significant increases in internal-external rotation (p = 0.0007) and maximum varus-valgus laxity (p < 0.0001) were measured. None of the pivot shift tests had a clinically positive result until the entire lateral collateral ligament was sectioned. CONCLUSIONS: This study suggests that, when the annular ligament is intact, either the radial collateral ligament or the lateral ulnar collateral ligament can be transected without inducing posterolateral rotatory instability of the elbow.     

Muscle forces and pronation stabilize the lateral ligament deficient elbow.

The influence of muscle activity and forearm position on the stability of the lateral collateral ligament deficient elbow was investigated in vitro, using a custom testing apparatus to simulate active and passive elbow flexion. Rotation of the ulna relative to the humerus was measured before and after sectioning of the joint capsule, and the radial and lateral ulnar collateral ligaments from the lateral epicondyle. Gross instability was present after lateral collateral ligament transection during passive elbow flexion with the arm in the varus orientation. In the vertical orientation during passive elbow flexion, stability of the lateral collateral ligament deficient elbow was similar to the intact elbow with the forearm held in pronation, but not similar to the intact elbow when maintained in supination. This instability with the forearm supinated was reduced significantly when simulated active flexion was done. The stabilizing effect of muscle activity suggests physical therapy of the lateral collateral ligament deficient elbow should focus on active rather than passive mobilization, while avoiding shoulder abduction to minimize varus elbow stress. Passive mobilization should be done with the forearm maintained in pronation.     

The effect of arthroscopic sectioning of the lateral ligament complex of the elbow on posterolateral rotatory stability

This study evaluates the relative roles of the radial collateral ligament, the lateral ulnar collateral ligament, and the overlying musculature in posterolateral rotatory instability of the elbow. Fourteen cadaveric upper limbs underwent sequential arthroscopic sectioning of the lateral collateral ligament complex. After sectioning, arthroscopic and fluoroscopic evaluation of a lateral pivot shift test was done. Minimal instability was noted after the first section, but no difference between radial collateral or lateral ulnar collateral ligament sectioning was found. A greater degree of instability was seen between the first and second cut ( P = .0001), but no significant difference was seen between sectioning the 2 groups ( P = .61). Complete instability occurred only after sectioning the overlying musculature. On the basis of this study, injury to both the radial collateral and lateral ulnar collateral ligaments is necessary to cause significant posterolateral rotatory instability of the elbow. Furthermore, the overlying musculature plays an important role in overall stability.     

The effect of radial head fracture size on elbow kinematics and stability.

This study determined the effect of radial head fracture size and ligament injury on elbow kinematics. Eight cadaveric upper extremities were studied in an in vitro elbow simulator. Testing was performed with ligaments intact, with the medial collateral (MCL) or lateral collateral (LCL) ligament detached, and with both the MCL and LCL detached. Thirty degree wedges were sequentially removed from the anterolateral radial head up to 120 degrees . Valgus angulation and external rotation of the ulna relative to the humerus were determined for passive motion, active motion, and pivot shift testing with the arm in a vertical (dependent) orientation. Maximum varus-valgus laxity was calculated from measurements of varus and valgus angulation with the arm in horizontal gravity-loaded positions. No effect of increasing radial head fracture size was observed on valgus angulation during passive and active motion in the dependent position. In supination, external rotation increased with increasing fracture size during passive motion with LCL deficiency and both MCL and LCL deficiency. With intact ligaments, maximum varus-valgus laxity increased with increasing radial head fracture size. With ligament disruption, elbows were grossly unstable, and no effect of increasing radial head fracture size occurred. During pivot shift testing, performed with the ligaments intact, subtle instability was noted after resection of one-third of the radial head. In this in vitro biomechanical study, small subtle effects of radial head fracture size on elbow kinematics and stability were seen in both the ligament intact and ligament deficient elbows. These data suggest that fixation of displaced radial head fractures less than or equal to one-third of the articular diameter may have some biomechanical advantages; however, clinical correlation is required.     

Non-anatomical reconstruction of lateral ulnar collateral ligament of the elbow after tumor resection

We present the case of an 80-year-old man with a tumor recurrence on his right arm 6 years after initial treatment. The lateral aspect of the elbow joint, involving overlaying skin, muscles, tendons, joint capsule, lateral collateral ligament complex, the lateral 1/3 of the capitellum, and lateral epicondyle of humerus were excised in the tumor resection. Intraoperative assessment revealed multidirectional instability of the elbow, and joint stabilization was needed. Because the lateral epicondyle was resected, graft placement in an anatomical position was impossible to carry out. Therefore, non-anatomical reconstruction of lateral ulnar collateral ligament with palmaris longus tendon graft was performed. The skin was reconstructed using an antegrade pedicled radial forearm flap. For wrist extension reconstruction, the pronator quadratus tendon was transferred to the extensor carpi radialis brevis tendon. One year after the operation, elbow range of motion was 5–130°. The patient remains symptom free. The Mayo elbow performance score is good. The Musculoskeletal Tumor Society rating score is excellent. To our knowledge, this is the first report of an elbow lateral ulnar collateral ligament reconstruction after tumor resection.     

The in vivo isometric point of the lateral ligament of the elbow

BACKGROUND: Many reports have discussed reconstruction of the lateral ulnar collateral ligament for the treatment of posterolateral rotatory instability of the elbow, but information regarding the isometric point of the lateral ligament of the elbow is limited. The purposes of the present study were to investigate the in vivo and three-dimensional length changes of the lateral ulnar collateral ligament and the radial collateral ligament during elbow flexion in order to clarify the role of these ligaments as well as to identify the isometric point for the reconstructed lateral ulnar collateral ligament on the humerus where the grafted tendon should be anchored. METHODS: We studied in vivo and three-dimensional kinematics of the normal elbow joint with use of a markerless bone-registration technique. Magnetic resonance images of the right elbows of seven healthy volunteers were acquired in six positions between 0 degrees and 135 degrees of flexion. We created three-dimensional models of the elbow bones, the lateral ulnar collateral ligament, and the radial collateral ligament. The ligament models were based on the shortest calculated paths between each origin and insertion in three-dimensional space with the bone as obstacles. We calculated two types of three-dimensional distances for the ligament paths with each flexion position: (1) between the center of the capitellum and the distal insertions of the ligaments (to investigate the physiological change in ligament length) and (2) between eight different humeral origins and the one typical insertion of the lateral ulnar collateral ligament (to identify the isometric point of the reconstructed lateral ulnar collateral ligament). RESULTS: The three-dimensional distance for the lateral ulnar collateral ligament was found to increase during elbow flexion, whereas that for the radial collateral ligament changed little. The path of the lateral ulnar collateral ligament gradually developed a detour because of the osseous protrusion of the lateral condyle with flexion. The most isometric point for the reconstructed lateral ulnar collateral ligament was calculated to be at a point 2 mm proximal to the center of the capitellum. CONCLUSIONS: The radial collateral ligament is essentially isometric, but the lateral ulnar collateral ligament is not. The lateral ulnar collateral ligament is loose in elbow extension and becomes tight with elbow flexion.     

Lateral collateral ligament deficiency of the elbow joint: A modeling approach

A computational model capable of predicting the effects of lateral collateral ligament deficiency of the elbow joint would be a valuable tool for surgical planning and prediction of the long‐term consequences of ligament deficiency. The purpose of this study was to simulate lateral collateral ligament deficiency during passive flexion using a computational multibody elbow joint model and investigate the effects of ligament insufficiency on the kinematics, ligament loads, and articular contact characteristics (area, pressure). The elbow was placed initially at approximately 20° of flexion and a 345 mm vertical downward motion profile was applied over 40 s to the humerus head. The vertical displacement induced flexion from the initial position to a maximum flexion angle of 135°. The study included simulations for intact, radial collateral ligament deficient, lateral ulnar collateral ligament deficient, and combined radial and lateral ulnar collateral ligament deficient elbow. For each condition, relative bone kinematics, contact pressure, contact area, and intact ligament forces were predicted. Intact and isolated radial collateral ligament deficient elbow simulations were almost identical for all observed outcomes. Minor differences in kinematics, contact area and pressure were observed for the isolated lateral ulnar collateral ligament deficient elbow compared to the intact elbow, but no elbow dislocation was detected. However, sectioning both ligaments together induced substantial differences in kinematics, contact area, and contact pressure, and caused complete dislocation of the elbow joint. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:1645–1655, 2016.     

桡骨小头切除晚期并发症的原因及机制探讨

目的：研究桡骨小头切除后晚期并发症产生的原因、发病机制和预防措施。方法：对２８例桡骨小头切除术后进行２年以上随访。同时对２０例新鲜上肢标本进行生物力学检测。结果：发现桡骨小头切除术后的晚期并发症有肘外翻畸形、创伤性关节炎、桡尺远侧关节脱位等。肘关节内侧副韧带损伤、骨间膜撕裂伤和桡尺关节远侧脱位是桡骨小头切除术后引起或加重晚期并发症的主要原因。结论：桡骨小头切除时,应考虑上述三种组织损伤是否存在及对预后的影响;桡骨小头切除在青少年患者应视为禁忌     

The effect of radial head excision and arthroplasty on elbow kinematics and stability

BACKGROUND: Radial head fractures are common injuries. Comminuted radial head fractures often are treated with radial head excision with or without radial head arthroplasty. The purpose of the present study was to determine the effect of radial head excision and arthroplasty on the kinematics and stability of elbows with intact and disrupted ligaments. We hypothesized that elbow kinematics and stability would be (1) altered after radial head excision in elbows with intact and disrupted ligaments, (2) restored after radial head arthroplasty in elbows with intact ligaments, and (3) partially restored after radial head arthroplasty in elbows with disrupted ligaments. METHODS: Eight cadaveric upper extremities were studied in an in vitro elbow simulator that employed computer-controlled actuators to govern tendon-loading. Testing was performed in stable, medial collateral ligament-deficient, and lateral collateral ligament-deficient elbows with the radial head intact, with the radial head excised, and after radial head arthroplasty. Valgus angulation and rotational kinematics were determined during passive and simulated active motion with the arm dependent. Maximum varus-valgus laxity was measured with the arm in a gravity-loaded position. RESULTS: In specimens with intact ligaments, elbow kinematics were altered and varus-valgus laxity was increased after radial head excision and both were corrected after radial head arthroplasty. In specimens with disrupted ligaments, elbow kinematics were altered after radial head excision and were similar to those observed in specimens with a native radial head after radial head arthroplasty. Varus-valgus laxity was increased after ligament disruption and was further increased after radial head excision. Varus-valgus laxity was corrected after radial head arthroplasty and ligament repair; however, it was not corrected after radial head arthroplasty without ligament repair. CONCLUSIONS: Radial head excision causes altered elbow kinematics and increased laxity. The kinematics and laxity of stable elbows after radial head arthroplasty are similar to those of elbows with a native radial head. However, radial head arthroplasty alone may be insufficient for the treatment of complex fractures that are associated with damage to the collateral ligaments as arthroplasty alone does not restore stability to elbows with ligament injuries.     

Instabilitätsrelevante Anatomie des Ellenbogens

Background

Detailed knowledge of elbow anatomy is crucial for diagnosis and therapy of instabilities around the elbow joint.

Discussion

Several anatomical structures stabilize the elbow joint. Due to its high congruency, the ulnohumeral joint protects the joint especially against varus as well as valgus stress and distraction particularly in full extension. The radiohumeral joint and proximal radioulnar joint are secondary stabilizers against valgus stress. The primary stabilizer against valgus stress is the medial collateral ligament which can be divided into an anterior and a posterior bundle. The lateral collateral ligament consists of the radial collateral ligament, the lateral ulnar collateral ligament and the annular ligament. The lateral collateral ligament in its entirety stabilizes the elbow against varus forces and posterolateral rotatory instability.

Conclusion

In addition, muscles spanning over the elbow joint are dynamic and static stabilizers via joint compression forces of the muscles and the orientation of muscle fibers that resemble those of the collateral ligaments.

     

The stability of the elbow following excision of the radial head and transection of the annular ligament. An experimental study

The stabilizing role of the lateral ligament complex and the radial head were investigated in ten osteoligamentous elbow preparations. The annular ligament was the prime stabilizer of the lateral aspect of the elbow. Transection of the annular ligament caused maximal varus and external rotatory instability of 13.7 degrees and 32.8 degrees respectively, with an elbow flexion about 70 degrees. Isolated excision of the radial head caused slight varus and external rotatory instability of 4.8 degrees and 10.4 degrees respectively, with an elbow flexion about 40 degrees. The lateral collateral ligament had only a minor stabilizing function of the elbow. The stability of the elbow after excision of the radial head may be improved by proper preservation of the annular ligament.     

超声结合应力实验在肘关节侧副韧带损伤中的临床意义分析

目的探讨在肘关节韧带损伤治疗中,应用超声检查判断肘关节稳定性的可靠性和临床意义。 方法选自2014年1月至2017年12月复旦大学附属华山医院收治的23例肘关节损伤病例,其中男11例、女12例,年龄15 ~ 68岁,平均年龄41.5岁。根据超声检查侧副韧带完整性作为依据,将术中应力实验结果作为治疗参考标准,以此决定肘关节韧带损伤的治疗方式。手术均采用韧带探查锚钉固定重建缝合术。随访肘关节功能评分和骨折愈合情况。 结果超声检查中发现14例患者内、外侧副韧带均撕裂;8例患者为外侧副韧带损伤,其中5例完全撕裂;1例患者为内侧副韧带损伤。以麻醉下应力实验结果作为金标准,其敏感性为97%,特异性为70%。采用Mayo肘关节功能评分系统,结果为优17例、良3例、中3例,优良率为87%。 结论对于肘关节侧副韧带损伤后稳定性的判断,超声检查是一项价廉、高效的检查方式,也有助于临床医生在术中结合应力实验结果对肘关节侧副韧带损伤处理作出判断。     

The stability of the elbow following excision of the radial head and transection of the annular ligament

Summary The stabilizing role of the lateral ligament complex and the radial head were investigated in ten osteoligamentous elbow preparations. The annular ligament was the prime stabilizer of the lateral aspect of the elbow. Transection of the annular ligament caused maximal varus and external rotatory instability of 13.7° and 32.8° respectively, with an elbow flexion about 70°. Isolated excision of the radial head caused slight varus and external rotatory instability of 4.8° and 10.4° respectively, with an elbow flexion about 40°. The lateral collateral ligament had only a minor stabilizing function of the elbow. The stability of the elbow after excision of the radial head may be improved by proper preservation of the annular ligament.     

Arthrolysis of the elbow and reconstruction of the collateral ligaments using a fascial strip of the triceps

Objective  Anatomic reconstruction of the collateral ligament of the elbow. Restoration of stability and function of the elbow. Reduction of pain. Improvement of range of motion. Indications  Instability of elbow. Insufficiency of ulnar or radial collateral ligament. Loss of the capsuloligamentous apparatus as seen after extensive resection of heterotopic ossifications involving ligaments and capsule. Contraindications  Unfavorable skin condition. Local infection. Damage to or previous operation of triceps tendon. Surgical Technique  Posterior, posterolateral or posteromedial approach. Dissection while always protecting the ulnar nerve. A neurolysis or a subcutaneous transposition may become necessary. Resection as complete as possible of ossifications and removal of ossified radial/ulnar capsuloligamentous apparatus. Exposure of the superficial fascial of triceps up to the olecranon. Harvesting of a fascial strip of the triceps 12 cm long and 1.5 cm wide on either the radial or ulnar side or both, left attached to the olecranon. Anatomic triangular reconstruction of the collateral ligaments with the fascial strip. Transosseous fixation. Wound closure in two layers. Results  In five patients, aged 25–59 years, an open arthrolysis combined with an ulnar triceps fascioplasty was done. In one instance it was combined with radial fascioplasty and once with a reconstruction of the radial collateral ligament using the tendon of the palmaris longus. Average duration of follow-up 2.2 years (8 months to 4.4 years). Assessment criteria and results: Function: marked improvement. Subjective assessment: no instability. Joint stability: laxity of ulnar collateral ligament grade I in one patient. Pain: excellent pain reduction. Range of motion: marked increase.     

A modified posterolateral approach to the elbow and proximal radioulnar joints

A modified posterolateral approach is useful for extensive exposure of the elbow and proximal radioulnar joints. The patient is placed prone and the elbow flexed over a padded support: a pneumatic tourniquet is placed proximally on the arm. The laterally curved skin incision extends from the center of the posterior surface of the arm, at the upper limit of the triceps tendon, to the back of the lateral epicondyle and thence to the posterior border of the ulna 3 finger-breadths distal to the tip of the olecranon. The large medial and smaller lateral flaps are secured with sutures. The ulnar nerve is exposed and protected. A distally based tongue of triceps tendon is fashioned and retracted downwards. The anconeus is separated from the extensor carpi ulnaris muscle and retracted medially with the underlying capsule. The common extensor origin and the lateral collateral ligament, with the adjacent capsule, are partially reflected from the humerus. Excellent exposure of the elbow and proximal radioulnar joints is easily achieved and visualization can be increased by putting a varus strain on the elbow.     

Surgical reconstruction for posterolateral rotatory instability of the elbow

We reviewed the results of 10 patients (10 elbows) who underwent surgical reconstruction for clinically symptomatic posterolateral rotatory instability of the elbow. The symptoms resulted from previous dislocation or a hyperextension or varus stress injury of the elbow. Two elbows had underlying preexisting varus deformity. Surgical reconstruction was performed with a tendon graft in 6 elbows and reattachment of the lateral ulnar collateral ligament to the humerus in 4. Postoperatively, no patient had residual instability or a positive pivot shift test in the elbow. Results were graded as excellent or good in 8 and fair in 2. All patients with excellent results had surgical reconstruction with a tendon graft. Subjective assessment revealed that all 10 patients were satisfied with the outcome of the surgery. Accurate recognition of posterolateral rotatory instability of the elbow is important for appropriate management. Surgical ligament reconstruction or repair is the most favorable treatment option for restoration of normal elbow function. The choice of reconstruction with a tendon graft appeared to produce better results than the reattachment of the injured ligament by itself in achieving an excellent outcome.     

肘关节后外侧旋转不稳定的研究进展

目的综述肘关节后外侧旋转不稳定(posterolateral rotatory instability,PLRI)的病理解剖、诊断及治疗进展。方法查阅国内外有关肘关节PLRI研究的相关文献,并进行综合分析。结果肘外侧韧带复合体(lateralcollateral ligament complex,LCLC)、桡骨头、肱骨小头及尺骨冠突损伤是导致肘关节PLRI的重要因素,跨越肘外侧的肌群起次要作用。临床检查主要包括侧方轴移试验、侧方轴移恐惧试验、撑椅征、俯卧撑试验、撑桌试验和后外侧旋转抽屉试验。影像学、关节镜及超声检查可以协助诊断PLRI。损伤的LCLC可采用骨性固定重建或软组织固定重建方式。结论 LCLC是PLRI的首要限制结构。超声能准确识别并测量正常的LCLC,有望成为一种可靠的无创检查方法。软组织固定重建方式避免了医源性骨折的缺点,是一种可选择的治疗方法。     

Metallic radial head arthroplasty improves valgus stability of the elbow

The stabilizing influence of radial head arthroplasty was studied in eight medial collateral ligament deficient anatomic specimen elbows. An elbow testing apparatus, which used computer controlled pneumatic actuators to apply tendon loading, was used to simulate active elbow flexion. The motion pathways of the elbow were measured using an electromagnetic tracking device, with the forearm in supination and pronation. As a measure of stability, the maximum varus to valgus laxity over the range of elbow flexion was determined from the difference between varus and valgus gravity loaded motion pathways. After transection of the medial collateral ligament, the radial head was excised and replaced with either a silicone or one of three metallic radial head prostheses. Medial collateral ligament transection caused a significant increase in the maximum varus to valgus laxity to 18.0 degrees +/- 3.2 degrees. After radial head excision, this laxity increased to 35.6 degrees +/- 10.3 degrees. The silicone implant conferred no increase in elbow stability, with a maximum varus to valgus laxity of 32.5 degrees +/- 15.5 degrees. All three metallic implants improved the valgus stability of the medial collateral ligament deficient elbow, providing stability similar to the intact radial head. The use of silicone arthroplasty to replace the radial head in the medial collateral ligament deficient elbow must be questioned. Metallic radial head arthroplasty provides improved valgus stability, approaching that of an intact radial head.     

Reconstruction of posttraumatic elbow instability

Successful reconstruction of posttraumatic elbow instability depends on restoration of the anatomic contributors to stability. The osseous and articular structures are paramount. The radial head and coronoid should be repaired or reconstructed and the olecranon (proximal ulna) should be repaired in anatomic alignment so that the contour and dimensions of the trochlear notch are restored and the radiocapitellar joint is aligned appropriately. The lateral collateral ligament complex is commonly disrupted and usually can be reattached to its origin from the lateral epicondyle. Patients with longstanding subluxation or dislocation may require temporary hinged external fixation or reconstruction of the collateral ligaments with tendon grafts.     

Anatomic and histologic studies of lateral collateral ligament complex of the elbow joint

We studied the gross and histologic anatomic characteristics of the lateral collateral ligament complex of the elbow joint from 15 cadavers to demonstrate its cross-sectional anatomy. The lateral ulnar collateral ligament adheres closely to the supinator, the extensor muscles, its intermuscular fascia, and the anconeus muscle and lies posterior to the radial collateral ligament. The lateral ulnar collateral ligament itself was identified with microscopy as a slender, poor structure consisting of the thick area of the posterolateral capsuloligamentous layer and a poorer structure than the anterior bundle of the medial collateral ligament as the primary stabilizer of the elbow joint. We believe that the lateral ulnar collateral ligament contributes to rather than is a major constraint to the posterolateral rotatory instability as part of the lateral collateral ligament complex with the surrounding tissues.