MRI of the annular ligament of the elbow: review of anatomic considerations and pathologic findings in patients with posterolateral elbow instability

A 70° Arthroscope Provides Better Visualization of the Medial Side of the Elbow Than a 30° Arthroscope

Purpose

To assess and quantify the improvement in visualization of humeral insertion of the medial collateral ligament (MCL) using a 70° scope compared with a 30° scope during elbow arthroscopy.

Methods

Twenty patients undergoing elbow arthroscopy for different pathologic conditions were enrolled in this single-center study. Visualization of the medial gutter of the elbow was evaluated by using both the 70° and the 30°scope. During the procedure, a needle was inserted at 45° with respect to the axis of the forearm, directed toward the intra-articular humeral emergence of the MCL. Four areas were established: the body (Z1), the lanceolate part (Z2), the tip of the needle (Z3), and the medial portion of the trochlea (Z4). The visible areas during arthroscopy using 2 different scopes were collected.

Results

The 70° scope allowed the detection of the first 3 areas in all patients (Z1, Z2, and Z3) and the visualization of the last area (Z4) in 19 patients (95%). On the other hand, the 30° scope allowed the detection of Z1 in 85% of patients, Z2 in 60% of patients, and Z3 in only 5% of patients. The medial portion of the trochlea was never visualized with the 30° scope. These findings were statistically significant.

Conclusions

The 70° scope improves visualization of the medial elbow compartment during elbow arthroscopy compared to the 30° scope, enhancing the extent of joint visualization and potentially permitting the detection of otherwise missed injuries in the difficult-to-reach areas of the joint.

Level of Evidence

Level II, diagnostic, prospective, cohort study.

Magnetic Resonance Imaging Manifestations of Annular Ligament Injuries in Children With Monteggia Fractures

BACKGROUND

Magnetic resonance imaging (MRI) is commonly performed in children with elbow injuries to visualize soft tissues such as the annular ligament. Herein, we investigated the MRI manifestations of annular ligament injuries in children with Monteggia fractures following attempted closed reduction.

METHODS

The clinical and imaging data of 88 children with acute Monteggia fractures treated at our hospital between 2015 and 2019 were analyzed. Clinically and radiographically, 67 patients achieved radiologic reduction of the radial head at the time of MRI, whereas 21 patients had a failed closed reduction. Annular ligament injury and superior radioulnar joint congruency were analyzed qualitatively, and the maximum superior radioulnar joint gap distance was measured.

RESULTS

MRI manifestations of annular ligament injury were primarily characterized as varying degrees of annular ligament displacement, as follows: I degree (10 patients), the annular ligament encircled the radial head without displacement; II degree (5 patients), the annular ligament was partially displaced but visibly encircled the radial head at the level of the radial notch; and III degree (73 patients), the annular ligament was completely displaced. In 15 patients with I and II degrees annular ligament injuries, the annular ligament encircled the radial head (maximum superior radioulnar joint gap distance, 1.2±0.3 mm), showing good congruency of the superior radioulnar joint. In 73 patients with III degree annular ligament injury, the annular ligament was displaced and did not encircle the radial head (maximum superior radioulnar joint gap distance, 3.3±2.7 mm; P <0.05), showing good congruency of the superior radioulnar joint in 25 of 73 patients, and significantly poor congruency in 48 of 73 patients ( P <0.05).

CONCLUSIONS

Annular ligament injuries in children with Monteggia fractures exhibit different degrees of displacement of the annular ligament. In I and II degree annular ligament injuries, the annular ligament still encircles the radial head. In III degree annular ligament injuries, the annular ligament is displaced away and is no longer around the radial head. Without the annular ligament restraining the radial head, the superior radioulnar joint is more likely to exhibit poor congruency and increased gap distance.

LEVEL OF EVIDENCE

Level II.

MRI of the Elbow: Interpretation of Common Orthopaedic Injuries

MRI is a valuable diagnostic tool that has become an essential part of an orthopaedic surgeon's practice. When acquired in the appropriate clinical setting, an MRI can direct patient management as surgical versus nonsurgical, guide surgical decision making, and even predict patient outcomes. The quality of MRI obtained and quality of the radiology report received varies. Ultimately, the orthopaedic surgeon must interpret the available imaging and apply these findings to treat the patient. The current day practicing orthopaedic surgeon should be familiar with interpreting common MRIs. Although subspecialized orthopaedic surgeons usually have experience and understanding of MRIs in their field, the general orthopaedic surgeon and those in-training will encounter the gamut of musculoskeletal MRIs. This review focuses on common injuries that can occur in the elbow and provides an approach to minimize missed findings.

MRI of the Elbow: How to Do It

The diagnostic cascade for elbow complaints starts with the physical examination and radiographs that already can clarify or rule out many causes. Depending on the suspected pathology, additional imaging is necessary. Magnetic resonance imaging (MRI) has the advantage of accurately demonstrating a broad spectrum of diseases. The main indication for noncontrast MRI of the elbow is chronic epicondylitis. For magnetic resonance (MR) arthrography, it is suspected chondral and osteochondral abnormalities. Indirect MR arthrography is an option when direct arthrography is not practicable. MR arthrography of the elbow with traction is feasible, with promising results for the assessment of the radiocapitellar cartilage.

Evaluation of the association between olecranon fracture and radial head subluxation or annular ligament displacement in children

Olecranon fractures are seen substantially more often in children than in adult and are potentially occult in nature. We noticed this fracture pattern in two cases of delayed Monteggia fracture. Our study purpose was to confirm whether olecranon fracture is associated with radial head subluxation or annular ligamentous displacement in children. In addition, we have developed an effective and simple approach to avoid serious treatment-related complications as much as possible. Forty-eight pediatric patients with olecranon fracture and normal radiocapitellar alignment on radiography were enrolled. All patients' fingers, forearms and elbows were examined carefully, and treated with a modified radial head reduction approach and then cast immobilization. MRI of the affected elbow was performed in 16 symptomatic patients. Overall, 70.83% of patients had a positive clinical finding of radial head subluxation. These symptomatic patients presented with similar clinical findings that typically included painful finger movement actively or passively and movement limitation of forearm and elbow. MRI showed that annular ligaments were interposed and trapped in the radiohumeral joint. In 34 symptomatic patients, 91.18% of them achieved fair radial head reduction during the first reduction attempt. Herein, 95.85 and 100% of patients reported excellent and satisfactory outcomes, respectively. Radial head subluxation occurred in most children with an olecranon fracture. We highly suggest performing a careful physical examination to identify this fracture pattern. Early reduction of the radial head with the modified approach may be a simple and primary option for emergency room doctors.

Acute elbow dislocation: comparison between magnetic resonance imaging and intra-operative finding of ligament injury

PURPOSE

The aim of this current study was to assess elbow ligament tears after dislocation using magnetic resonance imaging (MRI) and to correlate any pre-operative imaging with intra-operative findings of elbow ligament tears.

METHODS

We prospectively included 32 patients with acute elbow dislocation investigated by MRI at a means of five days from dislocation. A simple elbow dislocation was diagnosed in 14 patients (44%); associated bone injuries were identified in 18 elbows (56%). Surgical repair of elbow ligaments was carried out in 23 patients, and nine cases were treated non-operatively. A blinded MRI evaluation of all 32 elbows was performed by an orthopaedic surgeon (rater 1) and a musculoskeletal radiologist (rater 2).

RESULTS

Inter-rater agreement for MRI evaluation of 32 was poor for lateral ulnar collateral ligament (LUCL) tears, fair for radial collateral ligament (RCL), moderate for annular ligament (AL), and fair for ulnar collateral ligament (UCL). All tears were reported as complete by rater 1; 13/32 partial tears were identified by rater 2 (LUCL = 2, RCL = 2, UCL = 9). Correlation between surgical and MRI findings showed good inter-rater agreement for LUCL and AL tears in both raters. Agreement for RCL tear was poor for rater 1 and fair for rater 2; agreement for UCL tear was fair for rater 1 and poor for rater 2. Intra-operative findings showed ten radial head fractures (RHFs) and ten coronoid fractures (CFs). LUCL tears were found in the four cases of type II RHFs and in 3/4 cases of CFs. Bone injuries and ligament tears were not significantly associated.

CONCLUSION

MRI scan supported surgeons to identify soft tissue injuries and to address the most suitable surgical approach after acute elbow dislocation. Inter-observer agreement for intra-operative findings was high for LCL complex injuries and poor for UCL.

Magnetic resonance imaging of the elbow

Elbow pain can cause disability, especially in athletes, and is a common clinical complaint for both the general practitioner and the orthopaedic surgeon. Magnetic resonance imaging (MRI) is an excellent tool for the evaluation of joint pathology due to its high sensitivity as a result of high contrast resolution for soft tissues. This article aims to describe the normal imaging anatomy and biomechanics of the elbow, the most commonly used MRI protocols and techniques, and common MRI findings related to tendinopathy, ligamentous and osteochondral injuries, and instability of the elbow.

Double ulnar osteomy for the treatment of congenital radial head dislocation

OBJECTIVE

The aim of this study was to retrospectively evaluate the effects of our double osteotomy technique in the treatment of congenital radial head dislocation (CRHD).

METHODS

A total 14 children (14 elbows; 71.42% male; mean age: 9.31 ± 3.06 years) with CRHD who underwent double osteotomy of the proximal ulna between April 2010 and June 2015 were included in the study. The patients with CRHD were identified according to medical history, plain radiographs or magnetic resonance imagings. The outcomes were evaluated through comparison of the preoperative and postoperative motion range of elbow and Mayo Elbow Performance Score (MEPS).

RESULTS

After a follow-up of 13-35 months (22.29 ± 5.80), compared with pre-operation, the flexion (132.14 ± 3.23° vs 123.21 ± 7.75°, P = 0.003), extension (8.21 ± 4.21° vs 1.07 ± 3.50°, P = 0.003), and pronation of elbow (83.21 ± 4.21° vs 80.36 ± 4.14°, P = 0.011) improved significantly in all patients. Furthermore, the carrying angle was recovered to the normal level (5-15°) in all of these patients (18.57 ± 5.69° vs 8.21 ± 2.49°, P = 0.001). MEPS score was significantly increased postoperatively (96.79 ± 2.49 vs. 90.71 ± 1.82, P = 0.000), with the good outcome in CRHD patients.

CONCLUSION

The results of our study suggested that this double osteotomy on the proximal ulna might be an effective method for the treatment of CRHD.

LEVEL OF EVIDENCE

Level IV, Therapeutic Study.

The usefulness of ultrasound and the posterior fat pad sign in pulled elbow

INTRODUCTION

A pulled elbow is a common cause of acute elbow pain that is generally managed by a reduction maneuver without radiographic examination. However, children with atypical presentation with no history of abrupt longitudinal traction should undergo elbow imaging. This study aimed to investigate plain radiography findings and determine the usefulness of ultrasonography (US) in atypical pulled elbow.

MATERIALS AND METHODS

We retrospectively reviewed the medical records and images of 37 (22 males) consecutive patients with pulled elbow who presented with an atypical history or failed reduction between April 2015 and September 2018. Mean age at presentation was 4.34 years (range, 1.25-9.5 years). Of the 37 elbows, 20 were left elbows. The injury mechanism, incidence of the posterior fat pad sign on plain radiographs, and characteristic US findings, pre- and post- reduction, were investigated.

RESULTS

The original mechanisms of injury included slipping (n = 14), rolling over the arm (n = 7), vague history (n = 6), falling down (n = 6), abrupt longitudinal traction (n = 2), and direct injury (n = 2). On plain radiographs, six of the 37 elbows (16%) showed the posterior fat pad sign. Before the reduction, an entrapped supinator, a pathognomonic sign of pulled elbow, was identified on US in all cases. After reduction, the characteristic US findings showed a disentangled and swollen supinator (100%) and restored annular ligament (100%) in all successful cases. Although a click was not felt in three cases, the reductions were considered successful because the annular ligament was restored on US with free elbow motion.

CONCLUSION

Pulled elbow may be caused by atypical mechanisms of injury, such as slipping and rolling over the arm. Clinicians should be aware of the possibility of the posterior fat pad sign on plain radiographs of pulled elbow to prevent unnecessary immobilization. In such circumstances, US is a useful method for detecting an entrapped supinator and confirming adequate reduction via restoration of the annular ligament in children with atypical pulled elbow.

The elbow: review of anatomy and common collateral ligament complex pathology using MRI

The elbow is a complex joint whose stability is imparted by osseous and soft-tissue constraints. Anatomical and biomechanical knowledge of the supporting structures that provide stability to the medial and lateral elbow is essential to correctly interpret the pathological findings. Conventional MRI and MR arthrography are the imaging modalities of choice in the evaluation of elbow ligament injuries. Elbow instability can be classified according to timing (acute, chronic, or recurrent), the direction of displacement, the degree of displacement, and the articulations involved. This article reviews the MR imaging protocols recommended for each diagnosis and the normal anatomy and biomechanical aspects of the medial and lateral collateral ligament complex. We also present multiple cases of typical and atypical patterns of injury.

A combination of an anteromedial, anterolateral and midlateral portals is sufficient for 360° exposure of the radial head for arthroscopic fracture fixation

PURPOSE

Arthroscopic fixation of radial head fractures is an alternative to open reduction and internal fixation; the latter, however, presents the advantage of minimal soft-tissue damage. The exposure of the radial head for adequate screw placement can be technically challenging. The aim of this study was to evaluate the inter-observer agreement on the effective contact arc in the axial plane of the radial head of three different elbow arthroscopy portals.

METHODS

A fresh-frozen cadaver specimen was obtained and prepared in an arthroscopic setting. Standard anterolateral (AL), anteromedial (AM), and midlateral (ML) portals were established and a circular reference system was marked on the radial head. Ten orthopaedic surgeons were then asked to move the forearm from maximal supination to maximal pronation and indicate with a Kirschner wire from each portal the extension in which they would feel confident in placing a cannulated screw passing through the centre of the articular plane of the radial head (axial contact arc). The Shapiro-Wilk normality test was used to evaluate the normal distribution of the sample. A coefficient of variation (CoV) was calculated to determine agreement among observers.

RESULTS

The average arc of axial contact arc that could be contacted from the AM portal measured 150 ± 14.1°, or 41.7% of the radial head circumference; the one from the AL portal measured 257 ± 29.5°, or 71.4% of the radial head circumference; that from the ML portal measured 212.5 ± 32.6°, or 59.0% of the radial head circumference. Considering all three portals, the whole radial head circumference could be contacted. The AM portal showed the smallest CoV (9.4%) as compared to the AL (11.5%), and the ML (15.3%) portals.

CONCLUSIONS

With an appropriate use of the standard AL, AM, and ML portals, the whole radial head circumference can be effectively exposed for adequate fixation of radial head fractures. The contact arc of the AM portal presents the smallest variability among different observers and the AL portal shows a superiority in axial contact arc. This information is important for pre-operative planning, and helps to define the limits of arthroscopic radial head fracture fixation.

Annular ligament reconstruction in chronic Monteggia fracture-dislocations in the adult population: indications and surgical technique

Chronic Monteggia fracture is defined as dislocation of the radial head that is still present 4 weeks after injury. The cause may reside in residual ulnar deformity after internal fixation, in failure of annular ligament healing, or both. This situation may lead to elbow pain, decreased motion, neurologic problems and valgus deformity. The aim of the present study is to investigate indications and surgical technique for annular ligament reconstruction (ALR) in chronic Monteggia fractures. Relevant articles on annular ligament anatomy and biomechanics, clinical-radiographic evaluation of chronic Monteggia lesions and surgical techniques for ALR were reviewed. A case of an ALR in chronic Monteggia injury using a modified Bell Tawse surgical technique with triceps tendon autograft is presented. Little data exist on chronic Monteggia injury in the adult population. The annular ligament has a critical role in radial head stability. Nonetheless, bony alignment of the ulna is confirmed to be the most relevant feature to address in chronic Monteggia fractures. ALR has been advocated to address radial head instability both combined with ulna osteotomy and as a single procedure, with several surgical techniques described and controversial results reported. A modified Bell Tawse surgical technique resulted to be effective in the presented case. ALR seems to be indicated in chronic Monteggia fractures with normal bony alignment, without conclusive evidence on a preferable surgical technique.

Acute and overuse elbow trauma: radio-orthopaedics overview

Summary. The correct management of acute, subacute and overuse-related elbow pathologies represents a challenging diagnostic and therapeutic problem. While major trauma frequently requires a rapid surgical intervention, subluxation and minor trauma allow taking more time for diagnostics and planning the correct elective treatment after careful clinical and radiological investigation. In these conditions, communication between orthopaedic surgeon and radiologist allow to create a detailed radiology report, tailored to the patient’s and surgeon’s needs and optimal to plan proper management. Imaging technique as X-Ray, CT, US, MRI, CTA and MRA all belong to the radiologist’s portfolio in elbow diagnostics. Detailed knowledge of elbow pathology and its classification and of the possibilities and limits of each imaging technique is of crucial importance to reach the correct diagnosis efficiently. The aim of this review is to present the most frequent elbow pathologies and suggest a suitable diagnostic approach for each of them. (www.actabiomedica.it)

Point-of-Care Ultrasonography to Assist in the Diagnosis and Management of Subluxation of the Radial Head in Pediatric Patients: A Case Series

BACKGROUND

A subluxation of the radial head (SRH) is a clinical condition that commonly occurs in children under 6 years of age. History and physical examination findings typically include a child who presents with an elbow held in extension and with forearm pronation, after having suffered significant longitudinal traction on the arm, or after a fall on an outstretched hand. The diagnosis is often clinically obvious. The injury responds dramatically to closed reduction, and usually no imaging is required. However, cases with atypical presentations and patients who do not respond favorably to a reduction maneuver present clinical challenges, because the initial diagnosis of SRH may seem to be questionable or erroneous. Point-of-care ultrasound (POCUS) can assist decision-making and clinical management for these patients.

CASE REPORTS

We report three cases of SRH that were diagnosed and managed with POCUS in the emergency department. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: POCUS can assist in the diagnosis and management of patients with clinical suspicion of SRH, especially in cases of atypical presentations or cases in which the mechanism of injury is unknown. It is also an extremely valuable tool in determining postprocedure reduction success.

Annular ligament reconstruction with the superficial head of the brachialis: surgical technique and biomechanical evaluation

PURPOSE

The purpose of this study was to perform biomechanical testing of annular ligament (AL) reconstruction using the superficial head of the brachialis tendon (SHBT) as a distally based tendon graft. We hypothesized that posterior translation of the radial head following AL reconstruction with an SHBT graft does not significantly differ from intact specimens.

METHODS

Six fresh-frozen elbow specimens were used. The stability of the radial head against posterior translation forces (30 N) was evaluated in 0°, 45°, 90° and 120° of elbow flexion. Posterior translation was obtained for the intact AL, the sectioned AL and the reconstructed AL. Cyclic loading (100 cycles) in 90° of elbow flexion was performed for the intact and the reconstructed AL.

RESULTS

Posterior translation of the radial head decreased during elbow flexion in native specimens. Sectioning of the AL significantly increased instability over the full range of motion. AL reconstruction with the SHBT restored the stability of the proximal radius but-other than the native AL-was not influenced by elbow flexion. In 120° of flexion the native AL provided significantly more stability when compared to the reconstructed AL. Cyclic loading did not provide significant differences between native and reconstructed specimens.

CONCLUSIONS

We provide a feasible technique for AL reconstruction using the SHBT. The biomechanical results obtained in this study confirm the efficacy of the procedure. AL reconstruction restores the stability of the proximal radius, yet it cannot fully mimic the complex features of the intact AL.

MR Imaging of the Elbow

Almost all movements of the upper extremities during routine daily life and many athletic activities require a painless and stable elbow joint. Studying the elbow is a diagnostic challenge because of its complex anatomy. MR imaging is an extremely important tool in the evaluation of common elbow disorders, the spectrum of which ranges from obvious acute lesions to chronic overuse injuries whose imaging manifestations can be subtle.

Fractures of the Radial Head

Radial head fractures are the most common fractures around the elbow. Because they are often accompanied by ligamentous injuries, we recommend considering them to be osteoligamentous injuries rather than simple fractures, even in undisplaced or minimally displaced fractures. Surgeons should always suspect and actively exclude concomitant ligament tears. The incidence of these associated injuries increases with greater severity of the radial head fracture. However, the standard Mason classification system does not adequately address this problem, and all attempts to establish a new classification system that provides concise treatment algorithms have failed. This article discusses the current treatment options and the current controversies in nonsurgical therapy, open reduction and internal fixation (ORIF) and radial head replacement.