The appearance of the lateral ulnar collateral ligament on magnetic resonance imaging

Sensitivity and specificity of the posterolateral rotatory drawer test in the diagnosis of lateral collateral ligament insufficiency of the elbow

BACKGROUND

Numerous clinical tests are described for the diagnosis of chronic lateral collateral ligament (LCL) insufficiency of the elbow; however, none of these tests have been adequately assessed for sensitivity, with at most 8 patients included in previous studies. Furthermore, no test has had specificity assessed. The posterolateral rotatory drawer (PLRD) test is thought to have improved diagnostic accuracy over other tests in the awake patient. The aim of this study is to formally assess this test using reference standards in a large cohort of patients.

METHODS

A total of 106 eligible patients were identified for inclusion from a single-surgeon database of operative procedures. Examination under anesthetic (EUA) and arthroscopy were chosen as the reference standards to compare the PLRD test against. Only patients with a clearly documented PLRD test finding performed preoperatively in the clinic, and a clearly documented EUA and/or arthroscopic findings from surgery were included. A total of 102 patients underwent EUA, 74 of whom also underwent arthroscopy. Twenty-eight patients had EUA, and then an open procedure without arthroscopy. Four patients had arthroscopy without a clearly documented EUA. Sensitivity, specificity, and positive (PPV) and negative predictive values (NPV) were calculated with 95% confidence intervals.

RESULTS

Thirty-seven patients had a positive PLRD test, and 69 had a negative test. Compared to the reference standard of EUA (n = 102), the PLRD test had a sensitivity of 97.3% (85.8%-99.9%) and a specificity of 98.5% (91.7%-100%) (PPV = 0.973, NPV = 0.985). Compared to the reference standard of arthroscopy (n = 78), the PLRD test had a sensitivity of 87.5% (61.7%-98.5%) and a specificity of 98.4% (91.3%-100%) (PPV = 0.933, NPV = 0.968). Compared to either reference standard (n = 106), the PLRD test has a sensitivity of 94.7% (82.3%-99.4%) and a specificity of 98.5% (92.1%-100%) (PPV = 0.973, NPV = 0.971).

CONCLUSION

The PLRD test demonstrated an overall sensitivity of 94.7% and specificity of 98.5% with high positive and negative predictive values. This test is recommended as the primary diagnostic tool for LCL insufficiency in the awake patient and should be widely incorporated into surgical training.

Arthroscopic rod technique compared to stress ultrasound in the dynamic evaluation of lateral ligament instabilities of the elbow

INTRODUCTION

The purpose was to compare the arthroscopic rod technique to stress ultrasound in the dynamic assessment of lateral elbow instabilities.

MATERIALS AND METHODS

Fifteen elbows of eight specimen with a mean age of 66.4 ± 13.3 years were assessed in a prone position following a defined dissection setup. After evaluation of the native status, an arthroscopic dissection of the radial collateral ligament (RCL) or lateral ulnar collateral ligament (LUCL), and finally of entire capsuloligamentous structures was performed. Three raters examined each state (native, RCL or LUCL lesion, complete lesion) with the arthroscopic rod technique in 90° flexion and with stress ultrasound in 30 and 90° flexion. The intra-class correlation coefficient (ICC) was calculated to assess the interrater reliability as well as test-retest reliability for each testing modality (arthroscopy and ultrasound).

RESULTS

The arthroscopic rod technique showed a superior interrater and test-retest reliability of 0.953 and 0.959 (P < 0.001), respectively, when compared to stress ultrasound with an ICC of 0.4 and 0.611 (P < 0.001). A joint space opening during arthroscopy of > 6 mm humero-ulnar or > 7 mm humero-radial was indicative for a lateral collateral ligament lesion. However, a differentiation between an isolated RCL or LUCL tear was not possible. A lateral joint opening of ≥ 9 mm was only observed in complete tears of the lateral capsuloligamentous complex.

CONCLUSIONS

The arthroscopic rod technique showed a superior interrater and test-retest reliability when compared to stress ultrasound. Arthroscopic assessment for radial elbow instability was found to be reliable and reproducible. A joint gapping ≥ 9 mm in the arthroscopic evaluation is a sign for a complete insufficiency of the radial capsuloligamentous complex. However, it is not possible to precisely distinguish between a lesion of the RCL or LUCL by arthroscopy. On the basis of our results, dynamic ultrasound testing may be inappropriate to objectify lateral elbow instability.

Coronoid fixation and lateral collateral ligament repair in varus posteromedial rotatory instability of the elbow

Background

Varus posteromedial rotatory instability is a relatively rare elbow injury, that has been infrequently reported in published literature. We intended to evaluate the outcomes of surgical management of this rare injury with anteromedial coronoid fixation, and, in selected patients, lateral ulnar collateral ligament (LUCL) repair.

Methods

Between 2017 and 2020, we identified 12 patients with anteromedial coronoid fractures, and a varus posteromedial rotatory instability, who underwent surgery for fixation of the coronoid fracture, with or without LCL repair. All the included patients were either O'Driscoll subtype 2-2, or subtype 2-3. All the 12 patients were followed up for a minimum of 24 months, and their functional outcomes assessed using the Mayo Elbow Performance Score (MEPS).

Results

The mean MEPS recorded in our study was 92.08, and the mean range of elbow flexion achieved was 124.2°. The mean flexion contracture in our patients was 5.83°. Three of our twelve patients (25%) suffered from elbow stiffness even at final follow-up. The results were graded as Excellent in eight, Good in three, and Fair in one patient.

Conclusion

Coronoid fractures and LUCL disruptions associated with varus posteromedial rotatory instability can be reliably managed by employing a protocol that combines radiographic parameters, as well as intra-operative assessments of stability. While surgical intervention successfully restored stability, there is a learning curve to the management of these injuries and complications are not uncommon, particularly elbow stiffness. Hence, in addition to surgical fixation, emphasis should also be placed on intensive post-operative rehabilitation to improve outcomes.

Ultrasonography: an interesting imaging method for ligament assessment during the acute phase of closed elbow injuries

PURPOSE

To evaluate whether ultrasonography can be used to explore the medial and lateral ligament structures during the acute phase of a closed elbow injury.

METHODS

A single-center, prospective study performed between December 2019 and June 2020, including patients who suffered a radial head fracture or elbow dislocation. Two radiologists did a blinded analysis using ultrasonography of visibility, injury grade, and presence of bone avulsion for the radial collateral ligament (RCL), lateral ulnar collateral ligament (LUCL), annular ligament (AL), and anterior (MCLant) and posterior bundles (MCLpost) of the medial collateral ligament. The inter-rater agreement was calculated. The ultrasonography findings were compared with the intraoperative findings in the patients who subsequently underwent surgery.

RESULTS

Forty patients were included (28 radial head fractures and 12 elbow dislocations). The inter-rater agreement was strong for all the study parameters (kappa between 0.65 and 1), except for the visibility of the LUCL (kappa 0.52) and the visibility and appearance of the MCLpost (kappa 0.54 and 0.47, respectively). The injured ligaments were thicker than their contralateral counterparts (p < 0.05). In the 10 patients who underwent surgery, the radiological-surgical correlation was 100% for the RCL and medial ligaments and 70% for the LUCL.

CONCLUSION

Ultrasonography is a reproducible examination that can be used to assess the damage to elbow ligaments during the acute phase following an injury. This examination could be incorporated into the exploration protocol for elbow injuries during the preoperative assessment and to adapt the treatment.

Does sonography allow an objective and reproducible distinction between stable, hypermobile, and unstable elbow joints?

BACKGROUND

The diagnosis of residual or chronic elbow instability is often challenging. Sonography allows a dynamic examination of the elbow joint without any radiation exposure. The purpose of this prospective single-center study was to investigate the application of sonography for the evaluation of ligamentous instabilities of the elbow joint. Therefore, asymptomatic (stable) and acute dislocated (unstable) elbows were examined by sonography.

METHODS

A total of 72 elbows in 36 participants (23 women and 13 men; mean age, 40 ± 17 years [range, 18-82 years]) were examined. Group 1 (G1 [normal]) included 40 unaffected, asymptomatic elbow joints; 28 elbows belonged to 14 voluntary participants (bilateral), whereas 12 asymptomatic elbows belonged to patients who had an acute elbow dislocation (contralateral elbow). Group 2 (G2 [hypermobile]) included 20 hypermobile elbow joints in 10 participants (bilateral), and group 3 (G3 [unstable]) included 12 acute unstable elbow joints without bony lesions. Radiographic assessment included sonography of both elbow joints with standardized measurements of the neutral and stressed radiocapitellar and ulnohumeral distances (calculated as Δ values). Two investigators independently performed all measurements. Additionally, plain radiographs and magnetic resonance imaging of the affected elbow joints were obtained in G3.

RESULTS

On the radial side, the mean radiocapitellar Δ was statistically higher in G3 (2.2 ± 1.6 mm) than in G1 (0.5 ± 0.4 mm, P < .01) or G2 (0.8 ± 0.6 mm, P < .01). G3 also showed an increased ulnohumeral Δ (2.7 ± 0.7 mm) compared with G1 (1.0 ± 0.7 mm, P < .01) or G2 (0.9 ± 0.3 mm, P < .01). No significant differences in the mean radiocapitellar Δ (P = .06) and ulnohumeral Δ (P = .26) were found between G1 and G2. Within G3, Δ was significantly higher at the affected elbow joint than at the contralateral, unaffected elbow joint (P = .04 for the radial side and P = .04 for the ulnar side). The inter-rater correlation coefficient was 0.82 for the radial side and 0.74 for the ulnar side. Patients with collateral ligament injuries, diagnosed on magnetic resonance imaging, showed higher Δ values than those with intact collateral ligaments, although no significant difference was found.

CONCLUSION

Sonography of the elbow joint is a valuable imaging tool for the assessment of ligamentous instability. Nevertheless, a distinction between healthy and hypermobile elbow joints is not possible, and therefore, obtaining a complete clinical history and examination is vital. We further recommend comparing the affected elbow joint with the contralateral side to access intraindividual differences.

Ultrasonographic Technique, Appearance, and Diagnostic Accuracy for Common Elbow Sports Injuries

Ultrasonography is a valuable diagnostic imaging tool because of its availability, tolerability, low cost, and utility in real-time dynamic evaluation. Its use in diagnosing elbow injuries has expanded recently and continues to do so. In particular, stress ultrasonography represents a unique imaging technique that directly visualizes the ulnar collateral ligament (UCL) and allows the assessment of ligament laxity, offering an advantage over magnetic resonance imaging and magnetic resonance arthrography in this patient population. Furthermore, ultrasonography has shown particular usefulness in instances where invasive techniques might be less desirable. This is particularly important in athletes since more invasive procedures potentially result in lost time from their sport. Ultrasonography is an important imaging tool that complements a thorough history and physical examination in the evaluation of elbow injuries in athletes. The use of ultrasonography in orthopaedic sports medicine has been investigated previously; however, to our knowledge, there has been no comprehensive review regarding the utility of ultrasonography for common elbow injuries in athletes. The current study provides a comprehensive, detailed review of the utility and indications for the use of ultrasonography for common elbow injuries in athletes.

Analysis of magnetic resonance imaging-confirmed soft tissue injury pattern in simple elbow dislocations

BACKGROUND

The elbow is the second most commonly dislocated joint. Stability depends on the degree of soft tissue injury, with 2 proposed patterns, one starting laterally and the other medially. The purpose of this study was to describe the injured structures observed in magnetic resonance images (MRIs) in a prospective cohort of simple elbow dislocations.

METHODS

We evaluated 17 consecutive cases of simple elbow dislocations. Two musculoskeletal radiologists assessed the initial x-ray images and MRIs performed for all elbows. Radiologists evaluated the following soft tissue structures: medial collateral ligament complex (MCL), flexor-pronator muscle mass origin, anterior capsule (AC), posterior capsule, lateral collateral ligament complex (LCL), and extensor muscle mass origin. The radiologists were blinded to the study hypothesis.

RESULTS

The initial radiographs in 16 patients showed the dislocation was posterolateral in 12, posterior in 3, and posteromedial in 1. We observed complete AC tear in 12 patients, MCL in 10, and LCL in 9. The inter-rater reliability for the radiologists was 0.70 (substantial) for MRI.

CONCLUSIONS

In our series after simple elbow dislocation, complete AC tears were most common, followed by MCL and LCL tears. No single mechanism-related soft tissue injury pattern of simple elbow dislocation was observed, and different grades of soft tissue injury exist.

[Chronic ligamentous instability of the elbow]

BACKGROUND

Chronic ligamentous instability of the elbow is an important pathology as it is accompanied with pronounced dysfunction. Moreover, it represents an established risk factor for the development of osteoarthritis. Posterolateral rotatory instability (PLRI) caused by insufficiency of the lateral collateral ligament (LCL) is the most common type of chronic elbow instability and is usually a sequel of traumatic elbow dislocation. Chronic overload can lead to insufficiency of the ulnar collateral ligament (UCL) with subsequent valgus instability, especially in overhead athletes.

DIAGNOSTICS

Subjective instability and recurrent elbow dislocations are not always the main symptoms but elbow instability is instead often characterized by pain and secondary joint stiffness. Many clinical tests are available yet eliciting them can be difficult and inconclusive. A "drop sign" on lateral radiographs as well as the detection of collateral ligament injuries and joint incongruity on MRI scans can support the suspected diagnosis. In some cases, instability can only be verified by diagnostic arthroscopy.

TREATMENT

Reconstruction of the lateral ulnar collateral ligament (LUCL) for treatment of PLRI generally leads to good clinical results, yet recurrent instability remains an issue and has been reported in 8 % of cases. UCL reconstruction for chronic valgus instability leads to a return-to-sports rate of about 86 % in the overhead athlete. Ulnar neuropathy, which is seen in approximately 6 % of patients, represents the most common complication. On the rare occasion of multidirectional instability, the box-loop technique can be used for simultaneous reconstruction of the LUCL and UCL with a circumferential graft. 15 cases with promising results have been reported in literature thus far.

Posterolateral Rotatory Instability of the Elbow: Part II. Supplementary Examination and Dynamic Imaging Techniques

Currently, a number of examination and imaging techniques exist for diagnosing posterolateral rotatory instability of the elbow. Although the posterolateral rotatory drawer is the primary examination maneuver, other special tests include the lateral pivot-shift test, prone push-up test, chair push-up test, and tabletop push-up test. In addition, posterolateral rotatory instability can be evaluated using radiography, magnetic resonance imaging, dynamic fluoroscopy, or dynamic ultrasound. In this Technical Note, each of these tests is described in detail. Video instruction is also provided to further explain the techniques and provide examples of positive tests.

Interobserver and intraobserver agreement of ligamentous injuries on conventional MRI after simple elbow dislocation

Background

The primary objective of this study was to assess the interobserver and intraobserver agreement on ligamentous injuries on conventional magnetic resonance imaging (MRI) in acute simple elbow dislocation. The secondary objectives were to determine the interobserver agreement on the assessment of joint congruity, joint effusion, loose bodies and chondral lesions on conventional MRI.

Methods

Conventional MRIs (1.5 Tesla, elbow specific surface coil) of 30 patients (40.7 years; range 14–72) with simple elbow dislocations were evaluated by four blinded examiners. An analysis of the interobserver agreement of all raters and for several subgroups (radiologists, orthopaedics, experienced, non-experienced) was performed. The examiners assessed the integrity (intact, partial tear, complete tear) of the lateral collateral ligament (LCL), medial collateral ligament (MCL), extensor and flexor tendons, as well as the presence of joint congruity, joint effusion, loose bodies and chondral lesions. Agreement strength, correlation and proportion of exact agreement were determined for interobserver agreement, and intraobserver agreement analyses.

Results

Interobserver agreement of all examiners was fair to moderate for collateral ligaments (LCL: 0.441, MCL: 0.275). Exact agreement of all raters was found in 33.3% for the LCL and in 26.7% for the MCL. The both experienced examiners showed highest agreement strength for the LCL (0.619) and the radiologists showed highest agreement strength for the MCL (0.627), the proportion of exact agreement was 60.0% in both categories. A high proportion of exact agreement regarding joint congruity (90%), joint effusion (100%), loose bodies (96.7%) and chondral lesion (80%) was found among the radiologists. The evaluation of the intraobserver agreement revealed slight to substantial agreement (0.227 to 0.718) for the collateral ligaments.

Conclusions

This study shows difficulties in the evaluation of ligaments by conventional MRI technique as demonstrated by a weak inter- and intraobserver agreement. This should be the basis to develop new MRI quality standards with special focus on coronal oblique reconstructions to improve the evaluation of ligament injuries after simple elbow dislocations.

Posterolateral rotatory instability of the elbow

Posterolateral rotatory instability of the elbow is often caused by a complex injury to the lateral ulnar collateral ligament complex. This often leads to chronic mechanical symptoms of instability and pain. Surgical repair or reconstruction of the ligament is often required to stabilize the radiocapitellar joint. Multiple techniques have been described in the literature for repair or reconstruction of the lateral ligamentous complex with overall good clinical outcomes.

Elbow magnetic resonance imaging: imaging anatomy and evaluation

The elbow is a complex joint. Magnetic resonance imaging (MRI) is often the imaging modality of choice in the workup of elbow pain, especially in sports injuries and younger patients who often have either a history of a chronic repetitive strain such as the throwing athlete or a distinct traumatic injury. Traumatic injuries and alternative musculoskeletal pathologies can affect the ligaments, musculotendinous, cartilaginous, and osseous structures of the elbow as well as the 3 main nerves to the upper limb, and these structures are best assessed with MRI.Knowledge of the complex anatomy of the elbow joint as well as patterns of injury and disease is important for the radiologist to make an accurate diagnosis in the setting of elbow pain. This chapter will outline elbow anatomy, basic imaging parameters, compartmental pathology, and finally applications of some novel MRI techniques.

How should anteromedial coronoid facet fracture be managed? A surgical strategy based on O'Driscoll classification and ligament injury

BACKGROUND

Despite an improved understanding of coronoid anteromedial facet (AMF) fractures, the optimal treatment protocol and technique have not yet been established. The goals of the study were to describe the characteristics of AMF fractures, to suggest a surgical strategy, and to report the outcomes after treatment according to this protocol.

METHODS

This was a retrospective study of 19 patients with AMF fractures between 2010 and 2012. Eight patients were excluded because of secondary olecranon fracture, radial head fracture, and elbow dislocation, leaving 11 patients with isolated AMF fracture in the study cohort. There were 7 men and 4 women, with an average age of 42 years (range, 29-62 years). Fracture classification, injury pattern, and accompanying collateral ligament injury were analyzed. O'Driscoll subtype 1 fractures were treated with lateral collateral ligament (LCL) repair; O'Driscoll subtype 2 and subtype 3 fractures were treated with buttress plating and LCL repair. Plain radiographs were used to evaluate union, arthritic change, and joint articulation. Functional outcomes were evaluated with range of motion and the Mayo Elbow Performance Score.

RESULTS

Two patients had O'Driscoll anteromedial subtype 1 fracture, 4 patients had subtype 2, and 5 patients had subtype 3. Two patients with subtype 1 fracture had associated posterior dislocation; 9 patients with subtype 2 or subtype 3 had associated varus posteromedial injury. All 11 patients had associated LCL injury, and 6 patients had associated medial collateral ligament injury. The mean range of motion was 128°, and the average Mayo Elbow Performance Score was 89 points. Qualitatively, patient outcomes were scored excellent in 4 patients, good in 6 patients, and fair in 1 patient.

CONCLUSION

AMF fractures are almost always accompanied by collateral ligament injuries. Thus, our surgical strategies, which include collateral ligament repair, are able to stabilize and result in favorable clinical outcomes. On the basis of our results, we recommend LCL repair alone for subtype 1 fractures and buttress plating and LCL repair for subtype 2 and subtype 3 fractures.

Posterolateral rotatory instability of the elbow

Symptomatic posterolateral rotatory instability (PLRI) results from a lateral collateral ligament complex injury and presents with pain, clicking, and subluxation within the flexion and extension arcs of elbow motion. Often, symptoms and examination characteristics are subtle and can be easily misdiagnosed. Therefore, a thorough history and provocative physical examination maneuvers are important to correctly establish the diagnosis. Patients frequently have a history of elbow trauma such as an episode(s) of elbow dislocation, prior surgery, or previous cortisone injections. Radiographs and advanced imaging can aid in the diagnosis, and examination under anesthesia, manipulation with arthroscopic visualization, and/or stress radiographs can be confirmatory. Symptomatic cases of PLRI can be effectively treated with a repair or isometric ligament reconstruction.

MR imaging of the elbow in the injured athlete

This article summarizes key MR imaging findings in common athletic elbow injuries including little leaguer's elbow, Panner disease, osteochondritis dissecans, olecranon stress fracture, occult fracture, degenerative osteophyte formation, flexor-pronator strain, ulnar collateral ligament tear, lateral ulnar collateral ligament and radial collateral ligament tear, lateral epicondylitis, medial epicondylitis, biceps tear, bicipitoradial bursitis, triceps tear, olecranon bursitis, ulnar neuropathy, posterior interosseous nerve syndrome, and radial tunnel syndrome. The article also summarizes important technical considerations in elbow MR imaging that enhance image quality and contribute to the radiologist's success.

Simple elbow dislocations: evaluation, management, and outcomes

Elbow dislocations are common athletic injuries and occur during a fall onto an outstretched hand as a combination of axial-compressive and rotational-shear forces are conducted across the elbow joint. Simple dislocations are those that involve purely ligamentous injury, while complex dislocations include periarticular fractures. The initial assessment, radiographic evaluation, and on-field treatment of these injuries is discussed. Multiple reduction techniques are described with the patient positioned both supine and prone. Definitive management involves primarily nonoperative treatment with limited immobilization and early active range of motion to minimize joint contracture and hasten return to pre-injury activities. For unstable elbows, surgical treatment is usually appropriate. Operative management may involve exploration, lateral ligament repair or reconstruction, and assessment of the need for medial ligament repair or reconstruction. The role of arthroscopic and arthroscopically assisted surgery for elbow dislocation is evolving. Clinical series have shown that extended periods of immobilization (> 3 weeks) are associated with poor outcomes. Early active range of motion should be initiated as early as possible because late or recurrent instability is uncommon. Contracture is the most common adverse sequela of elbow dislocation. The literature indicates an average of 3° to 8° of extension loss with standard management of simple elbow dislocations.

Ultrasound assessment of the lateral collateral ligamentous complex of the elbow: imaging aspects in cadavers and normal volunteers

OBJECTIVE

The Lateral Collateral Ligamentous complex (LCL) is an important stabiliser of the elbow. It has a Y-shaped structure with three components. In this study, we sought to describe the ultrasound aspect of the individual components of this ligamentous complex and to evaluate the performance of ultrasound in both cadavers and in normal subjects.

METHODS

Ten cadaveric elbow specimens underwent high-frequency ultrasound. Two specimens were sliced and two were dissected for anatomical correlation. Ten elbows of normal subjects were also evaluated by ultrasound. The findings were compared.

RESULTS

The three components of the LCL could be visualised in all specimens and normal subjects with the exception of the proximal portion of one specimen. In 80% of the specimens and 100% of the healthy volunteers the proximal portion of the LCL could be separated from the extensor tendons.

CONCLUSION

High-resolution ultrasound can assess all components of the LCL of the elbow and can distinguish them from surrounding structures.

[Posterolateral rotatory instability of the elbow secondary to sprain]

We present a case of a 23 year-old man who presented to the emergency department after sustaining indirect trauma to the left elbow with unremarkable physical examination and normal radiographs. He presented again three weeks after with repeated episodes of locking and snapping of the left elbow occurring every time he attempted to rise from a chair while pushing the armrests, and when manoeuvring the steering wheel of his vehicle. On physical examination, the patient was apprehensive to the "lateral pivot shift" test as described by O'Driscoll et al. (1991) [1]. MRI of the left elbow demonstrated avulsion of the proximal epicondylar insertion of the lateral collateral ligament complex (LCLC). The "lateral pivot shift test" was positive under general anaesthesia. Lateral elbow radiograph taken during the test showed widening of the ulno-humeral joint space with posterior subluxation of the radial head. The patient underwent surgical treatment for posterolateral rotatory instability (PLRI) of the elbow. This case report aims to highlight the clinical aspects of the PLRI which may occur after a simple elbow sprain and be easily missed if not suspected; it also aims to draw attention to the importance of the "lateral pivot shift test" and the value of the stress lateral elbow radiograph in establishing the diagnosis of this rare and subtle entity.

Detailed MRI-anatomic study of the lateral epicondyle of the elbow and its tendinous and ligamentous attachments in cadavers

OBJECTIVE

The objective of our study was to document discrete bone landmarks in the lateral epicondyle of the humerus that represent the "footprints" of those tendons and ligaments that attach to it using MRI-anatomic correlation in cadavers.

MATERIALS AND METHODS

Thirty-three dried humeral specimens were inspected to document bone landmarks in the lateral epicondyle. MRI with anatomic correlation was performed in 10 additional cadaveric elbows. The locations of the tendinous and ligamentous attachments to the lateral epicondyle were determined with respect to the same osseous landmarks.

RESULTS

The surface of the lateral epicondyle ranged from a flat surface to a surface with up to six discrete landmarks: superior tubercle, anterior tubercle, posterior tubercle, intertubercular sulcus, rough area surrounding the tubercles, and epicondylar ridge. The radial collateral ligament attached to the superior aspect of the intertubercular sulcus and inferior aspect of the superior tubercle and was indistinguishable from the attachment of the lateral ulnar collateral ligament. The extensor carpi radialis brevis, extensor digitorum communis, and extensor digiti minimi had a common origin in the superior aspect of the lateral epicondyle. The extensor carpi ulnaris tendon arose from the posteroinferior aspect of the lateral epicondyle.

CONCLUSION

Our investigation documents osseous landmarks that are useful in the identification of the footprints of the tendons and ligaments that attach to the lateral epicondyle. Knowledge of these structures contributes to correct interpretation of MR images in persons with tendinous and ligamentous abnormalities in this region.

Elbow magnetic resonance imaging variants and pitfalls

Imaging variants of the elbow and pitfalls can be disconcerting and can lead to diagnostic mistakes. Inhomogeneities in the magnetic field and coil position can result in signal changes that may simulate abnormality. Bone signal and morphology variants, such as the islands of red marrow and the pseudodefect of the capitellum and intraarticular inclusions such as plicae, may be mistaken for abnormal findings. Variations of the distal biceps and triceps tendons and different aspects of the ligaments and their insertions, as well as nonpathologic signal and width changes in the ulnar nerve, are other examples of common pitfalls in magnetic resonance imaging of the elbow.

Sonography of the lateral ulnar collateral ligament of the elbow: study of cadavers and healthy volunteers

OBJECTIVE

The purpose of this study was to assess the utility of high-resolution sonography in identification and characterization of the size and echogenicity of the lateral ulnar collateral ligament of the elbow in cadavers and healthy volunteers.

SUBJECTS AND METHODS

The lateral ulnar collateral ligaments of four cadaveric elbows were imaged with a high-resolution linear-array ultrasound transducer. On localization, the ligaments were injected with 0.1% methylene blue under sonographic guidance. For confirmation of identification of the ligaments, the elbows were immediately dissected to reveal the exact location of the stain. The ligaments of both elbows of 35 healthy adult volunteers were imaged.

RESULTS

Surgical dissection confirmed injection of methylene blue into all four cadaveric ligaments. The lateral ulnar collateral ligament was identified bilaterally over the radial head in all 35 volunteers. The mean thickness of the ligament at this point was 1.2 mm in women and men. The proximal attachment of the ligament to the humerus was well visualized bilaterally in 94.3% of volunteers. The mean thickness at this point was 1.7 mm in women and 1.6 mm in men. The distal attachment on the ulna was well visualized in 90% of elbows. The ligament was hyperechoic in relation to muscle in all volunteers. Differences in ligament measurements with regard to sex and hand dominance were not significant. Ligament thickness correlated weakly with volunteer weight, height, body mass index, and age.

CONCLUSION

High-resolution ultrasound imaging is accurate for identification and measurement of normal lateral ulnar collateral ligaments. Therefore, ultrasound may prove valuable in assessment of abnormal lateral ulnar collateral ligaments.

Osborne-cotterill lesion: an osseous defect of the capitellum associated with instability of the elbow

OBJECTIVE

Posterolateral rotatory instability of the elbow is a diagnosis largely made by clinical examination; no relevant radiographic signs have been reported. We have seen four patients with an osseous defect and detachment of a fragment of bone in the posterolateral margin of the capitellum. These patients had chronic posterolateral rotatory instability of the elbow.

CONCLUSION

An osseous defect of the posterolateral corner of the capitellum is an uncommon finding that in each instance was associated with chronic posterolateral rotatory instability of the elbow. We termed this lesion the "Osborne-Cotterill lesion." We report our findings in these patients; when this lesion is diagnosed, clinicians should consider posterolateral rotatory instability.

Posterolateral rotatory instability of the elbow

Posterolateral rotatory instability is the most common type of symptomatic chronic instability of the elbow. In this condition the forearm complex rotates externally in relation to the humerus, causing posterior subluxation or dislocation of the radial head. The lateral ligament complex, radial head and coronoid process are important constraints to posterolateral rotatory instability, and their disruption is involved in the pathogenesis of this condition. The diagnosis relies on a high index of clinical suspicion, active and passive apprehension tests, and examination under anaesthesia. Surgical treatment has given consistently successful results. Open reconstruction of the lateral ligaments with a tendon graft has been the procedure of choice, with arthroscopic techniques emerging as a potential alternative.

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.

Elbow instability in children

Instability in the pediatric elbow can be secondary to trauma, developmental disorders, congenital anomalies, inherited disorders, or acquired systemic processes. The pediatric elbow presents unique challenges with regard to open growth plates, propensity for dislocation and spontaneous reduction, and increased time for the development of post-traumatic deformity into adulthood. The purpose of this article is to review current concepts of injuries leading to elbow instability, discuss how to recognize and treat the instability, and address other, nontraumatic causes of elbow instability.

Ligament and tendon injury to the elbow: clinical, surgical, and imaging features

Significant advances in the understanding of elbow anatomy, biomechanics, imaging, and surgical technique have been made over the last decade. Tendon injuries are often seen in athletes and physical laborers from repetitive eccentric overload. Ligament injuries are commonly seen in throwing athletes or after elbow dislocation. Magnetic resonance imaging has proven valuable for diagnosing and monitoring most of these soft tissue injuries, and effective surgical techniques have evolved to address them. This article describes typical clinical findings associated with ligament and tendon injuries in the elbow as well as common surgical therapies. The use of magnetic resonance imaging is highlighted throughout because this modality has revolutionized noninvasive evaluation of the elbow.