Elbow instability

An understanding of elbow instability is predicated on knowledge of the anatomy of the lateral collateral ligament complex and of the mechanism and kinematics of elbow subluxation and dislocation. The lateral collateral ligament complex is the key structure involved in recurrent elbow instability and it is virtually always disrupted in elbow dislocations that result from a fall. The ulnar part of the lateral collateral ligament complex (also known as lateral ulnar collateral ligament) is the critical portion of the ligament complex securing the ulna to the humerus and preventing posterolateral rotatory instability. The kinematics of elbow subluxation and dislocation are a three dimensional coupled motion referred to as posterolateral rotatory instability in which the forearm rotates off the humerus in valgus/external rotation during flexion from the extended position. Elbow instability is diagnosed on clinical examination by the lateral pivot-shift test, the posterolateral rotatory apprehension and drawer tests and on radiographic examination by performing stress x-rays. While the lateral pivot-shift test is difficult to perform, the posterolateral rotatory drawer test is much less difficult. The most sensitive test, however, is the posterolateral rotatory apprehension test. A positive apprehension test in a patient presenting with a history of recurrent painful clicking, snapping, clucking, or locking of the elbow should lead one directly to the suspected diagnosis of posterolateral rotatory instability. Treatment is surgical, by repair or reconstruction of the lateral collateral ligament complex, specifically the ulnar part. Deficiencies of the coronoid and/or radial head must be addressed.     

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.     

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.     

Posterolateral rotatory instability of the elbow

Recurrent posterolateral rotatory instability of the elbow is an apparently undescribed clinical condition that is difficult to diagnose. We treated five patients, ranging in age from five to forty years, who had such a lesion and in whom the instability could be demonstrated only by what we call the posterolateral rotatory-instability test. This test involves supination of the forearm and application of a valgus moment and an axial compression force to the elbow while it is flexed from full extension. The elbow is reduced in full extension and must be subluxated as it is flexed in order to obtain a positive test result (a sudden reduction of the subluxation). Flexion of more than about 40 degrees produces a sudden palpable and visible reduction of the radiohumeral joint. The elbow does not subluxate without provocation. The cause for this condition, we think, is laxity of the ulnar part of the lateral collateral ligament, which allows a transient rotatory subluxation of the ulnohumeral joint and a secondary dislocation of the radiohumeral joint. The annular ligament remains intact, so the radio-ulnar joint does not dislocate. Operative repair of the lax ulnar part of the lateral collateral ligament eliminated the posterolateral rotatory instability, as revealed intraoperatively in our five patients.     

Ligamentous reconstruction for posterolateral rotatory instability of the elbow.

Eleven consecutively seen patients who had posterolateral rotatory instability of the elbow joint were managed operatively. The radial collateral-ligament complex was advanced and imbricated in three of them. In seven patients, the ulnar band of the radial collateral ligament (the lateral ulnar collateral ligament) was reconstructed with the palmaris longus tendon and in two of the seven, the reconstruction was augmented with a prosthetic ligament. The ligament was reconstructed with the lateral one-third of the triceps fascia in the remaining patient. Stability was obtained in ten patients, and seven patients had an excellent functional result. There was one failure in one of the patients in whom the ulnar band of the radial collateral ligament had been reconstructed with the palmaris longus tendon and augmented with a prosthetic ligament.     

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.     

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 appearance of the lateral ulnar collateral ligament on magnetic resonance imaging

The lateral ulnar collateral ligament is an important element of the elbow's lateral capsuloligamentous complex, and loss of integrity contributes to posterolateral rotatory instability. However, the normal appearance on magnetic resonance imaging is poorly defined. The purpose of this study was to assess the appearance of the lateral ulnar collateral ligament of asymptomatic elbows on magnetic resonance imaging. We performed magnetic resonance imaging on 20 asymptomatic elbows. The lateral ulnar collateral ligament was identified as a hypointense structure originating from the lateral epicondyle and inserting on the proximal ulna in 10 cases (50%) and was ambiguous in the other 10 elbows. The identified lateral ulnar collateral ligament images included areas of high signal intensity, which was confusing because it suggested ligamentous disruption within the ligament. These results indicate that magnetic resonance imaging is not reliable for diagnosing lateral ulnar collateral ligament injuries at the present time. Further progress in magnetic resonance imaging will be clinically useful for diagnosing abnormalities of the lateral ulnar collateral ligament.     

Single-strand reconstruction of the lateral ulnar collateral ligament restores varus and posterolateral rotatory stability of the elbow

Because of a lack of biomechanical studies of lateral elbow ligament reconstruction in the literature, the initial stability afforded by 3 different techniques of lateral ulnar collateral ligament reconstruction was evaluated in 8 cadaveric elbows. The arm was mounted in a testing apparatus, and passive flexion was performed with the arm in varus and valgus orientations. A pivot shift test was performed with the arm in the vertical orientation. An electromagnetic tracking device was used to quantify motion pathways. After intact testing, each specimen underwent sectioning of the radial collateral and lateral ulnar collateral ligaments from the lateral epicondyle. Reconstruction of the lateral ulnar collateral ligament was performed in a randomized sequence, consisting of proximal single-strand, distal single-strand, and double-strand tendon grafts. Division of the radial collateral and lateral ulnar collateral ligaments from the lateral epicondyle caused a significant decrease in rotational stability when the pivot shift test was being performed (P <.0001). Varus-valgus stability also decreased after transection of the radial collateral and lateral ulnar collateral ligaments (P <.0001). Reconstruction of the lateral ulnar collateral ligament restored elbow stability to that of the intact state. There was no significant difference in stability between the single- and double-strand repair techniques (P >.05). This study demonstrates that both single- and double-strand reconstructions restore varus and posterolateral elbow stability and may be considered appropriate reconstructive procedures in patients with symptomatic insufficiency of the lateral ligaments of the elbow.     

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.     

Arthroscopic electrothermal shrinkage of chronic posterolateral elbow instability: good or moderate outcome in 21 patients followed for an average of 2.5 years

Background The lateral collateral ligament complex is the key structure involved in recurrent elbow instability. Treatment is surgical, by repair or reconstruction of the lateral collateral ligament complex. We evaluated the effect of arthroscopic electrothermal shrinkage for treatment of chronic posterolateral rotator elbow instability.

Methods 21 patients, median age 32 (24-50) years, suffering from chronic lateral elbow instability underwent arthroscopic electrothermal ligament shrinkage with a bipolar shrinkage probe. All patients were available for follow-up after median 30 (8-48) months.

Results No complications were seen. The Morrey score increased from 40 to 77 points. The result was moderate (50-80 points) in 10 patients, and in the other patients a good result was achieved (80-95 points). The manual stress radiography showed a mean lateral joint opening of 13 (8-18) mm preoperatively. During follow-up, it decreased to 2 (1-4) mm.

Interpretation Our findings suggest that arthroscopic bipolar ligament shrinkage is sufficient for the treatment of chronic posterolateral rotator elbow instability.     

Chronic lateral elbow instability

Posterolateral rotatory instability of the elbow is the most common pattern of chronic lateral elbow instability. The primary lesion in posterolateral rotatory instability is injury or attenuation of the lateral ulnar collateral ligament. Posterolateral rotatory instability is diagnosed on the basis of careful history taking and specific physical examination techniques. Reconstruction of the lateral ulnar collateral ligament with repair of the surrounding soft tissue structures is recommended in patients who have symptoms of recurrent lateral instability. Open and arthroscopic reconstruction techniques have resulted in improvement of elbow function and satisfactory results in most patients, although mild limitation in terminal extension of the elbow is a common finding.     

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.     

Arthroscopic electrothermal shrinkage of chronic posterolateral elbow instability: Good or moderate outcome in 21 patients followed for an average of 2.5 years

Background The lateral collateral ligament complex is the key structure involved in recurrent elbow instability. Treatment is surgical, by repair or reconstruction of the lateral collateral ligament complex. We evaluated the effect of arthroscopic electrothermal shrinkage for treatment of chronic posterolateral rotator elbow instability.

Methods 21 patients, median age 32 (24–50) years, suffering from chronic lateral elbow instability underwent arthroscopic electrothermal ligament shrinkage with a bipolar shrinkage probe. All patients were available for follow-up after median 30 (8–48) months.

Results No complications were seen. The Morrey score increased from 40 to 77 points. The result was moderate (50–80 points) in 10 patients, and in the other patients a good result was achieved (80–95 points). The manual stress radiography showed a mean lateral joint opening of 13 (8–18) mm preoperatively. During follow-up, it decreased to 2 (1–4) mm.

Interpretation Our findings suggest that arthroscopic bipolar ligament shrinkage is sufficient for the treatment of chronic posterolateral rotator elbow instability.     

Ultrasonographic assessment of the ulnar collateral ligament and medial elbow laxity in college baseball players

BACKGROUND: The prevalence of medial elbow instability is high in athletes who throw, such as baseball players. The aim of this study was to assess the medial aspect of the elbow with ultrasonography to detect changes in baseball players. METHODS: Ultrasonography of the medial aspect of the elbow was performed, while gravity stress was applied with the elbow in 90 degrees of flexion, on thirty college baseball players (twelve pitchers and eighteen fielders) to assess medial joint laxity and deformity of the ulnar collateral ligament. The dominant (throwing) extremity was compared with the contralateral extremity. Clinical data were correlated with ultrasonographic findings. RESULTS: The medial joint space was significantly wider on the throwing side than it was on the contralateral side (2.7 mm and 1.6 mm, respectively; p < 0.01), and the proximal part of the ulna was shifted significantly laterally on the throwing side (p < 0.01). Angular deformity of the ulnar collateral ligament was found in five subjects, and it was significantly associated with lateral shift of the proximal part of the ulna (p < 0.01). Medial elbow pain was associated with widening of the medial joint space (p < 0.05) and with the presence of angulation of the ulnar collateral ligament (p < 0.01). CONCLUSIONS: Medial elbow laxity and elbow valgus on the throwing side of baseball players were increased compared with those in nonplayers. Angular deformity of the ulnar collateral ligament suggests that the ligament bends over the distal-medial edge of the trochlea. Ultrasonography can provide useful information about the condition of the ulnar collateral ligament and about medial elbow laxity in athletes who throw.     

肘关节后外侧旋转不稳的诊断及治疗

目的:研究手术重建肘关节外侧韧带复合体治疗肘关节后外侧旋转不稳定的疗效。方法:收集2013年1月至2015年1月20例肘关节后外侧旋转不稳患者的资料,男12例,女8例;年龄30~60岁,平均45.5岁;右侧16例,左侧4例。9例有肘关节脱位史,6例有肘关节骨折史,5例无外伤史,所有患者为闭合性损伤。结合患者病史、查体及术前X线、MRI检查明确诊断。经保守治疗时间超过2个月无效,20例均在全麻下取患侧掌长肌腱作为重建移植物,行肘外侧韧带复合体的重建,术后根据患者情况进行个体化康复锻炼。结果:术后20例均获随访,未出现感染、肘关节功能明显受限等现象,平均随访16个月(12~23个月)。采用美国特种外科医院HSS评分标准和VAS评分标准对手术前后肘关节功能进行评分,术前HSS评分75.2±8.3,术后94.1±5.4;术前VAS评分6.7±3.2,术后2.3±1.5;术后评分均优于术前。结论:肘外侧韧带复合体是肘关节后外侧旋转不稳定的首要限制结构,重建肘外侧韧带复合体是治疗肘关节后外侧旋转不稳定的一种有效方法。     

Posterolateral rotatory instability of elbow: An uncommon entity

Posterolateral rotatory instability of elbow is an exceedingly uncommon entity, which results from injury to the lateral ligamentous complex. Failure of adequate healing of lateral collateral ligaments may necessitate its surgical repair or reconstruction. We describe here a boy 12 years of age who was initially treated as soft tissue injury and later presented with instability of the same elbow. He later required repair of lateral ulnar collateral ligament.     

Mid-radial portal for operative arthroscopy of the elbow: cadaveric and clinical description of a new portal

We report a previously undescribed portal on the lateral aspect of the elbow-the mid-radial portal-and discuss the safety and use of this portal in a clinical practice via cadaveric dissection and retrospective review of 61 patients. It is located midway between the proximal anterolateral and the direct lateral portals at the level of the radiocapitellar joint and serves as a second portal on the lateral side of the elbow for use anteriorly or posteriorly. The portal penetrates the common extensor origin and courses between the radial and ulnar bands of the lateral collateral ligament complex prior to penetrating the joint capsule.In the clinical series, the mid-radial portal was used in 40 (66%) of 61 cases. The most common procedures involved removal of loose bodies and debridement in the radiocapitellar joint or posterolateral gutter. Follow-up in the clinical series averaged 6 months. No major and 2 minor complications, neither of which could be directly attributed to the use of the mid-radial portal, were found. Specifically, no cases of postoperative lateral instability existed. The previously undescribed mid-radial portal is a safe, effective option for arthroscopy on the lateral aspect of the elbow.     

Ligamentous reconstruction around the elbow using triceps tendon

Posttraumatic instability of the elbow joint can be osseous or ligamentous. Ligamentous instability can be in valgus or in posterolateral rotatory direction. Rupture of both the lateral and medial collateral ligament of the elbow can be seen as an isolated injury, or it can be part of a more complex injury such as a dislocation. Persistent insufficiency of the lateral collateral ligament of the elbow results in posterolateral rotatory instability. Insufficiency of the medial collateral ligament, the anterior part in particular, results in valgus instability. Persistent symptoms after nonoperative treatment are an indication for reconstruction. In the past, ligamentous reconstruction at both the lateral and medial side was performed using palmaris tendon graft through bony drill holes.In this article I describe a new technique using ipsilateral triceps tendon, fixed in drill holes using bioabsorbable interference screws. This technique allows simplified graft tensioning and improved graft fixation, and avoids the risk of fracturing of the bony tunnels. An accelerated rehabilitation protocol can be applied. The final result depends on proper isometric reconstruction, associated lesions or degeneration of the elbow joint and adequate after-treatment. Taking these factors into account, the technique described shows promising short-term results.     

Ligamentous reconstruction around the elbow using triceps tendon

Posttraumatic instability of the elbow joint can be osseous or ligamentous. Ligamentous instability can be in valgus or in posterolateral rotatory direction. Rupture of both the lateral and medial collateral ligament of the elbow can be seen as an isolated injury, or it can be part of a more complex injury such as a dislocation. Persistent insufficiency of the lateral collateral ligament of the elbow results in posterolateral rotatory instability. Insufficiency of the medial collateral ligament, the anterior part in particular, results in valgus instability. Persistent symptoms after nonoperative treatment are an indication for reconstruction. In the past, ligamentous reconstruction at both the lateral and medial side was performed using palmaris tendon graft through bony drill holes. In this article I describe a new technique using ipsilateral triceps tendon, fixed in drill holes using bioabsorbable interference screws. This technique allows simplified graft tensioning and improved graft fixation, and avoids the risk of fracturing of the bony tunnels. An accelerated rehabilitation protocol can be applied. The final result depends on proper isometric reconstruction, associated lesions or degeneration of the elbow joint and adequate after-treatment. Taking these factors into account, the technique described shows promising short-term results.