Sonographic anatomy of the ankle

Ultrasound Imaging of Ankle Retinacula: A Comprehensive Review

The retinacula of the ankle are specialized anatomical structures characterized by localized thickenings of the crural fascia that envelop the deep components of the lower leg, ankle and foot. The ankle retinacula include the extensor retinacula, the peroneal retinacula and flexor retinaculum. Despite their potential to explain persistent and unexplained pain following an injury, these structures are often overlooked or incorrectly diagnosed. Hence, this comprehensive review was performed aiming to investigate the use and the methodology of US imaging to assess ankle retinacula. The search was performed on PubMed and Web of Science databases from inception to May 2024. The MeSH keywords used were as follows: "Ankle Retinacula", "Foot Retinacula", "Superior extensor retinaculum", "Inferior extensor retinaculum", "peroneal retinaculum", "superior peroneal retinaculum", "inferior peroneal retinaculum", "flexor retinaculum", "Ultrasound Imaging", "Ultrasound", "Ultrasonography" and "Ultrasound examination". In total, 257 records underwent screening, resulting in 22 studies meeting the criteria for inclusion after the process of revision. Data heterogeneity prevents synthesis and consistent conclusions. The results showed that advanced US imaging holds promise as a crucial tool to perform an US examination of ankle retinacula, offering static and dynamic insights into ankle retinacula pathology. Understanding normal anatomy and US imaging is essential for accurately identifying injuries. Future research should focus on clinical trials to validate parameters and ensure their reliability in clinical practice.

Presurgical Perspective and Postsurgical Evaluation of the Plantar Fascia

The plantar fascia is an important structure in the foot that acts as a major stabilizer of the longitudinal arch, along with the midfoot ligaments and intrinsic and extrinsic muscles. It is composed predominantly of longitudinally oriented collagen fibers that vary in thickness and are organized into bundles closely associated with the interstitial tissues of the foot. This composition enables the plantar fascia to withstand the weight-bearing forces concentrated on the foot while standing, jumping, walking, or running. This article discusses the normal anatomy and the various pathologies that affect the plantar fascia with an emphasis on presurgical and postoperative appearances on magnetic resonance and ultrasonography imaging.

Diagnostic Performance of Ultrasonography for Evaluation of Osteoarthritis of Ankle Joint: Comparison With Radiography, Cone-Beam CT, and Symptoms

OBJECTIVES

To determine the diagnostic performance of ultrasonography (US) for evaluation of the ankle joint osteoarthritic (OA) changes. Cone-beam computed tomography (CT) was used as the gold standard and US performance was compared with conventional radiography (CR). As a secondary aim, associations between the imaging findings and ankle symptoms were assessed.

METHODS

US was performed to 51 patients with ankle OA. Every patient had prior ankle CR and underwent cone-beam CT during the same day as US examination. On US, effusion/synovitis, osteophytes, talar cartilage damage, and tenosynovitis were evaluated. Comparison to respective imaging findings on CR and cone-beam CT was then performed. Single radiologist blinded to other modalities assessed all the imaging studies. Symptoms questionnaire, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), was available for 48 patients.

RESULTS

US detected effusion/synovitis of the talocrural joint with 45% sensitivity and 90% specificity. For the detection of anterior talocrural osteophytes, US sensitivity was 78% and specificity 79%. For the medial talocrural osteophytes, they were 39 and 83%, and for the lateral talocrural osteophytes 54 and 100%, respectively. Considering cartilage damage of the talus, US yielded a low sensitivity of 18% and high specificity of 97%. Overall, the performance of US was only moderate and comparable to CR. The imaging findings showed only weak associations with ankle symptoms.

CONCLUSIONS

The ability of US to detect ankle OA is only moderate. Interestingly, performance of CR also remained moderate. The associations between imaging findings and WOMAC score seem to be weak in ankle OA.

A problem-based approach in musculoskeletal ultrasonography: heel pain in adults

Musculoskeletal ultrasonography (US) has unique advantages, such as excellent spatial resolution for superficial structures, the capability for dynamic imaging, and the ability for direct correlation and provocation of symptoms. For these reasons, US is increasingly used to evaluate problems in small joints, such as the foot and ankle. However, it is almost impossible to evaluate every anatomic structure within a limited time. Therefore, US examinations can be faster and more efficient if radiologists know where to look and image patients with typical symptoms. In this review, common etiologies of heel pain are discussed in a problem-based manner. Knowing the common pain sources and being familiar with their US findings will help radiologists to perform accurate and effective US examinations.

Quick and simple test to evaluate severity of acute lateral ankle sprain

Background/objective

For early return to sports after a lateral ankle sprain (LAS) and recurrence prevention, effective rehabilitation and gradual return to sports should be initiated while predicting the return time based on the appropriate severity evaluation immediately after injury. However, since severity evaluations performed in previous studies required large space and stairs and involved high-revel activity, their use as a test and index to evaluate severity after LAS was not appropriate considering convenience and risk of re-injury. Therefore, a quick and simple test was developed to evaluate the severity of acute LAS. This study aimed to verify the association between ankle function for severity evaluation and anterior talofibular ligament (ATFL) injury type by ultrasonography and to clarify the usefulness for acute LAS severity evaluation of the single-leg loading (SLL) test.

Methods

In total, 50 patients (34 men, 16 women) out of 58 patients who visited our sports clinic within 3 days after acute LAS and who conformed to the study criteria were included in this study. During the first visit, SLL test and objective/subjective ankle joint evaluation were performed. The SLL test consists of single-leg standing, single-leg heel raising and single-leg hopping, and patients were classified into four levels from 1 to 4 according to results. In addition, ultrasonographic evaluation was performed within 1 week after the first visit to evaluate the type of ATFL injury. Type I was defined as intact ATFL, Type II as swollen ATFL with an almost intact fibrillar pattern and Type III as ATFL appearing swollen with a disrupted fibrillar pattern. The relationship between the SLL test and each evaluation item was investigated using Spearman's correlation coefficient.

Results

As a result of the SLL test, 15 patients had Level 1 (30%), 19 Level 2 (38%), 5 Level 3 (10%) and 11 Level 4 (22%). With regard to correlation coefficients of the SLL test, Japanese Society for Surgery of the Foot ankle/hindfoot scale and sports activity were r_s = 0.71 (p < 0.001) and r_s = 0.66 (p < 0.001), respectively, showing a significant positive correlation. SLL test and the type of ATFL injury also showed a significant negative correlation (r_s = −0.58, p < 0.001).

Conclusions

The SLL test was a simple and useful test that can be used as an index to evaluate the severity of acute LAS.

Ultrasound Analysis of Lateral Ankle Ligaments in Functional Ankle Instability

The anterior talofibular ligament and the calcaneofibular ligament were sonographically investigated in 16 patients with functional ankle instability (FAI) and 16 controls under neutral and standardized stress conditions of 15 kp with a TELOS device. Clinical investigation revealed a significantly higher rate of a positive anterior drawer and talar tilt (p <0.001, respectively), significantly increased supination (p = 0.047) of the right ankle joint and increased plantarflexion (p = 0.009) of the left ankle joint in the FAI group compared with controls. Significantly higher rates of inhomogeneity and hypo-echogenicity were sonographically observed in both ligaments in the FAI group (p < 0.05, respectively). The anterior talofibular ligament was significantly longer under stress conditions, and the calcaneofibular ligament was significantly longer under both neutral and stress conditions in the FAI group (p < 0.05, respectively). Peritendinous edema of the peroneal tendons was found in 22% of the FAI group and 6% of controls.

Non-rotator cuff calcific tendinopathy: ultrasonographic diagnosis and treatment

Calcific tendinopathy is a condition that is related to the deposition of calcium, mostly hydroxyapatite crystals, within the tendons. The shoulder and the hip are commonly affected joints, but calcific tendinopathy may occur in any tendon of the body. While there is an extensive literature on the ultrasound diagnosis of calcific tendinopathy of the shoulder, there are only sporadic reports on other sites. This review combines the experience of our centers and a thorough analysis of the literature from the last 45 years (1972-2017) in order to highlight the localizations beyond the rotator cuff, their ultrasound characteristics and therapeutic possibilities.

Ankle flossing alters periarticular stiffness and arterial blood flow in asymptomatic athletes

BACKGROUND

Tissue flossing has been introduced to increase impaired range of motion (ROM) and flexibility, to enhance prevention and rehabilitation, as well as to improve athletic performance; however, limited evidence exists for its efficacy. The aim of the present study was to evaluate the effects of ankle flossing on periarticular stiffness and perfusion via Acoustic Radiation Force Impulse (ARFI) elastography and Power Doppler Sonography (PDS).

METHODS

Twenty-one healthy students (age: 24±2 years, BMI: 22±3 kg/m²) were recruited as participants. ARFI was performed to evaluate periarticular ankle stiffness involving the anterior ankle capsule (AC), the anterior talofibular ligament (ATFL) and the peroneus brevis muscle (PBM). Arterial blood flow was assessed in the dorsal pedal artery. Measurements were taken under resting conditions (T<inf>0</inf>) and twice after standardized ankle flossing (T<inf>1</inf>: 0 min., T<inf>2</inf>: 60 min. postintervention).

RESULTS

The connective tissue stiffness decreased significantly after ankle flossing compared to baseline (T<inf>1</inf>, AC: -12%, P=0.009, ATFL: -12%, P=0.003; T<inf>2</inf>, AC: -8%, P=0.002, ATFL: -9%, P=0.015). The PBM stiffness decreased by 3% (T<inf>1</inf>, P=0.304) and 4% (T<inf>2</inf>, P=0.029). The perfusion measures significantly increased by 30% at T<inf>1</inf> compared to baseline (P=0.001); no significant changes were observed at T<inf>2</inf> (P=0.492).

CONCLUSIONS

This is the first study demonstrating decreased AC and ATFL stiffness and reactive hyperemia to be key mechanisms of ankle flossing. Additional studies must be conducted to determine whether changes in biomechanical properties influence dynamic ankle stability.

Intra- and inter-rater reliability of ultrasound measures of the anterior cruciate ligament

Diagnostic ultrasound has accurately and reliably been utilized by clinicians to determine ACL morphology at the tibial insertion site, specifically measuring the entire ACL diameter, the anteromedial bundle (AM), and the posterolateral bundle. However, intra- and inter-rater reliability of these measures in a research setting is unknown. The purpose of this study was to determine intra- and inter-rater reliability of ultrasound measures of ACL diameter and AM diameter in researchers with low-to-moderate ultrasound experience. We hypothesized that intra- and inter-rater reliability of ACL and AM diameters would reach acceptable levels, a minimal intraclass correlation (ICC) of 0.6 and a desired ICC of 0.8 with an α of 0.05 and β of 0.20. Fourteen volunteers participated in this study. During the ACL ultrasound measures, participants were seated with their knee flexed to at least 90°. Each rater recorded two images of both the right and left ACL and AM bundles. Next, participants were re-examined by rater one for intra-rater reliability analyses. Two-way random ICCs were conducted for intra-rater (between sessions) and inter-rater reliability for both the full ACL and the AM bundle diameters. Standard errors between sessions for Rater 1's AM bundle and ACL diameters were less than 0.03 cm. Intra-rater reliability was higher in AM bundles compared to full ACL, 0.76 versus 0.59, respectively. Standard errors between Rater 1 and Rater 2 were less than 0.03 cm. Inter-rater reliability was higher in AM bundles compared to full ACL, 0.71 versus 0.41, respectively. The results of the study indicate researchers with low-to-moderate training with ultrasound measures can locate and measure the ACL, but with greater reliability using the AM.

Ultrasonographic Assessment of Deltoid Ligament Integrity in Ankle Fractures

BACKGROUND

Regardless of fibular status, the presence of a superficial deltoid ligament disruption or a combination of deep and superficial deltoid ligament disruption is central to the decision-making process in treating ankle fractures. The aims of the present study were to test whether ultrasonography can assess deltoid ligament integrity and to determine its validity and reliability by comparing it with gravity stress radiography.

METHODS

A consecutive series of 81 eligible patients with a nondisplaced or minimally displaced fibula fracture identified on a standard radiograph were prospectively enrolled. All patients underwent gravity stress radiography and ultrasonography. Image analysis included the layer type, integrity, and tear site of the deltoid ligament. Ultrasound validity and intra- and interobserver reliability were assessed by the interpretations of the first author and an independent observer who were blinded to the results.

RESULTS

Of all patients, 64 (79.0%) had a deltoid ligament disruption; most of the tears were of both the superficial and deep layers, partial and proximal attachment tears, and only 8 (12.5%) were complete tears. Patients with an intact deltoid ligament had a mean medial clear space (MCS) value of 2.7 ± 0.5 mm, and those with deltoid ligament tears had a mean MCS value of 5.9 ± 3.4 mm (P < .001). In a comparison between ultrasonography and gravity radiography, we found a sensitivity of 100% versus 97%, a specificity of 90% versus 100%, a positive predictive value of 97% versus 100%, and a negative predictive value of 100% versus 90%, respectively. The intra- and interobserver reliability was evaluated as almost perfect in all conditions. In a comparison between ultrasonography and gravity radiography, we found a sensitivity of 100% versus 97%, a specificity of 90% versus 100%, a positive predictive value of 97% versus 100%, and a negative predictive value of 100% versus 90%, respectively.

CONCLUSION

Ultrasonography proved to be an accurate tool, allowing the identification of deltoid ligament disruption and the involved components in a more dynamic fashion. Its relative ease of use and lack of ionizing radiation make it a useful and confident technique that can be performed by an orthopedist.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

Dorsiflexion is more feasible than plantar flexion in ultrasound evaluation of the calcaneofibular ligament: a combination study of ultrasound and cadaver

PURPOSE

Ultrasound (US) is a valuable tool for the evaluation of chronic lateral instability of the ankle; however, the feasibility of US for calcaneofibular ligament (CFL) assessment remains unknown. This study aimed to depict and compare CFL on US in various ankle positions to determine the optimal method for evaluating CFL with US and to interpret US findings using cadaveric specimens.

METHODS

The US study included 43 ankles of 25 healthy individuals. The CFL was scanned with US in 20° plantar flexion, neutral position, 20° dorsiflexion and maximum dorsiflexion. The distances between fibula and CFL were compared. The cadaveric study included macroscopic qualitative observation of the dynamic change of CFL in 7 ankles and quantitative observation of the directions of CFL and footprints in 17 ankles.

RESULTS

In the US study, the mean distance (mm) between fibula and CFL was 7.3 ± 1.3 in 20° plantar flexion, 6.7 ± 1.6 in neutral position, 4.3 ± 2.5 in 20° dorsiflexion and 3.1 ± 2.1 in maximum dorsiflexion. The more dorsiflexed the ankle was, the shorter the distance between fibula and CFL was (Jonckheere's trend test p < 0.001). In the cadaveric study, the CFL fibres were aligned parallel between the mid-substance and the fibular attachment in maximum dorsiflexion, whilst CFL was reflected and rotated in plantar flexion.

CONCLUSIONS

The whole length of the CFL, including its fibular attachment, is more likely to be visualized with US in dorsiflexion than in plantar flexion due to the direction of the CFL at the fibular attachment, which is parallel with the mid-substance in maximum dorsiflexion.

LEVEL OF EVIDENCE

IV.

[Development and clinical application of ankle prosthesis]

OBJECTIVE

To review the development and clinical application of ankle prosthesis.

METHODS

The recent literature on ankle prosthesis design and clinical application was reviewed and analyzed.

RESULTS

Compared with the hip and knee prostheses, the ankle prosthesis develops slowly and has been developed to the third generation. The ankle joint has a special structure of multi-axis movement. The design of the first and second generations of prostheses is not conformed to the biomechanics of the ankle. The third generation of prosthesis is more conform to the characteristics of ankle biomechanics, with high postoperative survival rate and satisfactory clinical outcome.

CONCLUSION

At present, the survival rate of ankle prosthesis is low, and there is still much room for improvement in biomechanics, materials, and other aspects.

Ankle and Foot Ultrasound: Reliability of Side-to-Side Comparison of Small Anatomic Structures

OBJECTIVES

In sonography of clinically relevant small structures of the ankle and foot, the healthy contralateral side can be used as a reference to identify subtle abnormalities. Intrasubject side-to-side variability must be minimal. The aim of this study was to assess the reliability of side-to-side sonographic evaluation of small structures of the ankle and foot.

METHODS

Thirty healthy volunteers were prospectively studied. Small structures of the ankle and foot were evaluated bilaterally by 2 musculoskeletal radiologists in separate sessions. The deep peroneal nerve, superior extensor retinacula, calcaneofibular ligament, superior peroneal retinacula, tibialis posterior tendon, tibial nerve, Achilles tendon, plantaris tendon, plantar fascia, and sural nerve were considered. To assess intra- and interreader agreements, 30 (100%) examinations were repeated. A nonparametric statistic was used.

RESULTS

Data were not normally distributed (P > .001). Intrareader agreement was k = 0.67 (95% confidence interval, 0.57-0.78) and interreader agreement was k = 0.73 (95% confidence interval, 0.68-0.77). The mean values and standard deviation for all the structures were 0.36 ± 1.85 mm. The overall coefficient of variation was 18.5%. The intraclass correlation coefficient was 0.93 (95% confidence interval, 0.92-0.94).

CONCLUSIONS

In ankle and foot sonography, the healthy contralateral side can be used as a reference during a real-time musculoskeletal ultrasound evaluation of small structures.

Comparison of high resolution ultrasonography with clinical findings in patients with ankle pain

Aim: The aim of this study was to investigate the diagnostic accuracy of high resolution ultrasonography for the assessment of painful ankle joint as compared with the clinical findings. Material and Methods: A prospective study was conducted on 136 patients having history of ankle pain and referred to the Department of Radiodiagnosis and Imaging for ultrasonography. Statistical analysis: Comparison of ultrasonography findings and clinical findings was done using McNemar Test. Results: 136 patients with 218 pathologies of the ankle joint were analyzed. Of these, 178 pathologies were clinically suspected, but 206 were diagnosed with ultrasonography. This difference was statistically significant (p value = 0.000). Conclusion: Ultrasonography is an excellent tool for evaluating patients with ankle pain, especially in cases of lateral ligament pathologies, tendinous pathologies, joint effusion, and miscellaneous pathologies. It can be used as the primary imaging investigation because it allows a rapid, dynamic, and cost-effective examination of the ankle joint. However, ultrasonography has limitations when using it to evaluate a suspected posterior talofibular ligament injury, marrow abnormalities, and deep seated pathologies, for which MRI should be incorporated for a diagnosis.

Aim: The aim of this study was to investigate the diagnostic accuracy of high resolution ultrasonography for the assessment of painful ankle joint as compared with the clinical findings. Material and Methods: A prospective study was conducted on 136 patients having history of ankle pain and referred to the Department of Radiodiagnosis and Imaging for ultrasonography. Statistical analysis: Comparison of ultrasonography findings and clinical findings was done using McNemar Test. Results: 136 patients with 218 pathologies of the ankle joint were analyzed. Of these, 178 pathologies were clinically suspected, but 206 were diagnosed with ultrasonography. This difference was statistically significant (p value = 0.000). Conclusion: Ultrasonography is an excellent tool for evaluating patients with ankle pain, especially in cases of lateral ligament pathologies, tendinous pathologies, joint effusion, and miscellaneous pathologies. It can be used as the primary imaging investigation because it allows a rapid, dynamic, and cost-effective examination of the ankle joint. However, ultrasonography has limitations when using it to evaluate a suspected posterior talofibular ligament injury, marrow abnormalities, and deep seated pathologies, for which MRI should be incorporated for a diagnosis.

Pseudo-tear appearance of the posterior tibiotalar ligament on fluid-sensitive sequences

PURPOSE

This study aimed at studying the MR imaging appearance of the tibiotalar ligament in asymptomatic volunteers.

MATERIALS AND METHODS

Fourty-two ankles were imaged on a 3T MR system using proton density weighted images with fat saturation (TR, 2969 ms; TE 30 ms; NA, 2; slice thickness, 2.5 mm). Subjects with acute ankle conditions or history of previous trauma were not included in the study group. Images were obtained in the three orthogonal planes. The posterior tibiotalar ligament was assessed on coronal imaging, by consensus of two radiologists. The signal intensity was recorded as isointense, hypointense, or hyperintense relative to muscle. The morphology of the ligament was classified as homogenous or striated. Descriptive statistics were obtained.

RESULTS

There were 8 men and 14 women with a mean age of 24.7 years (range 19-43 years). The ligaments were classified as hyperintense in 30/42 (70%) of ankles and isointense in 9/42 (21%) of ankles. A striated appearance was seen in 34/42 (80%) of ankles.

CONCLUSION

The posterior deep deltoid ligament is commonly hyperintense. It is usually striated although it can be homogeneously hyperintense. This appearance simulates a tear.

Intrasheath Instability of the Peroneal Tendons: Dynamic Ultrasound Imaging

Peroneal intrasheath instability is a painful snapping condition of the lateral ankle. It consists of a transient retromalleolar subluxation of the peroneal tendons without disruption of the superior peroneal retinaculum or evidence of a previous definite trauma. In type A intrasheath instability, the peroneus longus and brevis tendons are intact, and there is an intertendinous intrasheath switch. In type B intrasheath instability, the peroneus brevis tendon has a longitudinal split tear through which the peroneus longus subluxates. Both types can be missed on a physical examination because there is no displacement of the peroneal tendons over the lateral malleolus. Dynamic ultrasound is the imaging modality of choice for evaluating retromalleolar subluxation of the peroneal tendons. This review article aims to provide an overview of the anatomic basis for peroneal intrasheath instability and provide physicians with guidelines for its ultrasound assessment.

Acoustic radiation force impulse tissue characterization of the anterior talofibular ligament: a promising noninvasive approach in ankle imaging

OBJECTIVES

The anterior talofibular ligament (ATFL) is the most frequently injured ligament during inversion strains of the ankle. The purpose of this study was to evaluate the feasibility of acoustic radiation force impulse (ARFI) elastography and to determine the in vivo mechanical properties of the ATFL in healthy athletes.

METHODS

Sixty healthy athletes (32 female, 28 male; 28.9 ± 2.1 years) were recruited from the medical and sports faculty. ARFI values, represented as shear wave velocities (SWVs) as well as conventional ultrasound were obtained for the ATFL in neutral ankle position. A clinical assessment was performed in which the American Orthopaedic Foot & Ankle Society (AOFAS) Ankle-Hindfoot Score and the functional ankle ability measure (FAAM) were collected. Interobserver and intraobserver reliability (repeated sessions and repeated days) were assessed using an intra class correlation coefficient (ICC) and typical error (TE) calculation in absolute (TE) and relative units as coefficient of the variation (CV).

RESULTS

SWV values of the ATFL had an average velocity of 1.79 ± 0.20 m/s for all participants, with an average of 1.72 ± 0.36 m/s for females and 1.85 ± 0.31 m/s for males. The interobserver and intraobserver reliability revealed an ICC of 0.902 and 0.933 (TE of 0.67 (CV: 5.2%) and 0.52 (CV: 3.84%)), respectively. FAAM and AOFAS revealed the best possible scores.

CONCLUSION

ARFI seems to be a valuable diagnostic modality and represents a promising imaging marker for the assessment and monitoring of ankle ligaments in the context of acute and chronic ankle instabilities; ARFI could also be used to investigate loading or sport dependent adaptions.

Ultrasound of the Distal Insertions of the Ankle and Foot Tendons With Anatomical Correlation: A Review

The distal insertions of the tendons crossing the ankle as well as the tendons originating in the foot are less well known by radiologists. We review the anatomy and ultrasound appearance of these insertions using our own cadaveric sectioning and dissection. The ultrasound images were correlated with anatomical slices. Occasionally magnetic resonance images were also used for better understanding. Understanding the normal appearance of these tendon insertions is important for diagnosing pathology in this region.

Ankle and midfoot ligaments: Ultrasound with anatomical correlation: A review

We present a detailed overview of anatomical and US features of ankle and midfoot ligaments based on our own dissections and cadaver studies as well as US imaging in cadavers and volunteers. The ligament anatomy about the ankle and midfoot is complex. Most ligaments are superficial and hence very well accessible for US. US technique to obtain optimal visualization however is difficult and requires a learning curve. We discuss US technique in detail for each individual ligament. We divided the ligaments in different groups: tibiofibular ligaments, Bassett's ligament, lateral collateral ligament complex (anterior talofibular ligament, calcaneofibular ligament, lateral talocalcaneal ligament, posterior talofibular ligament), medial collateral ligament complex, spring ligament, Chopart joint ligaments (bifurcate ligament, dorsal talonavicular ligament, lateral calcaneocuboid ligament, long and short plantar ligaments), Lisfranc ligaments, sinus tarsi ligaments.

The 2017 EULAR standardised procedures for ultrasound imaging in rheumatology

BACKGROUND

In 2001, the European League Against Rheumatism developed and disseminated the first guidelines for musculoskeletal (MS) ultrasound (US) in rheumatology. Fifteen years later, the dramatic expansion of new data on MSUS in the literature coupled with technological developments in US imaging has necessitated an update of these guidelines.

OBJECTIVES

To update the existing MSUS guidelines in rheumatology as well as to extend their scope to other anatomic structures relevant for rheumatology.

METHODS

The project consisted of the following steps: (1) a systematic literature review of MSUS evaluable structures; (2) a Delphi survey among rheumatologist and radiologist experts in MSUS to select MS and non-MS anatomic structures evaluable by US that are relevant to rheumatology, to select abnormalities evaluable by US and to prioritise these pathologies for rheumatology and (3) a nominal group technique to achieve consensus on the US scanning procedures and to produce an electronic illustrated manual (ie, App of these procedures).

RESULTS

Structures from nine MS and non-MS areas (ie, shoulder, elbow, wrist and hand, hip, knee, ankle and foot, peripheral nerves, salivary glands and vessels) were selected for MSUS in rheumatic and musculoskeletal diseases (RMD) and their detailed scanning procedures (ie, patient position, probe placement, scanning method and bony/other landmarks) were used to produce the App. In addition, US evaluable abnormalities present in RMD for each anatomic structure and their relevance for rheumatology were agreed on by the MSUS experts.

CONCLUSIONS

This task force has produced a consensus-based comprehensive and practical framework on standardised procedures for MSUS imaging in rheumatology.

Ultrasound evaluation of bursae: anatomy and pathological appearances

A bursa is an extra-articular sac that may communicate with a joint and functions to decrease friction between tendons and either bone or skin. Bursae can be classified as native and non-native (adventitious) bursae. The native bursae are lined with a synovial membrane and occur at predictable anatomical sites; knowledge of these normal structures can help distinguish them from other pathological entities. An adventitious bursa can form at sites of friction rather than at predictable anatomical sites, but otherwise have imaging features similar to native bursae. Bursal distention can occur from many pathological processes, most commonly resulting from chronic overuse injury. When imaging bursal pathological conditions, there is often an overlap of imaging findings, regardless of the cause. In general, ultrasound of a distended bursa reveals a fluid collection with either simple anechoic or more complex hypoechoic fluid. Bursal distention is characteristically unilocular and compressible, unlike other structures such as ganglion cysts, which are usually multilocular and non-compressible. This article reviews the anatomical locations of common bursae and shows pathological examples using ultrasound. Knowledge of typical locations and imaging appearances of bursae can aid in narrowing the differential diagnosis and guiding further management and treatment decisions.

Imaging of plantar fascia disorders: findings on plain radiography, ultrasound and magnetic resonance imaging

Plantar fascia (PF) disorders commonly cause heel pain and disability in the general population. Imaging is often required to confirm diagnosis. This review article aims to provide simple and systematic guidelines for imaging assessment of PF disease, focussing on key findings detectable on plain radiography, ultrasound and magnetic resonance imaging (MRI). Sonographic characteristics of plantar fasciitis include PF thickening, loss of fibrillar structure, perifascial collections, calcifications and hyperaemia on Doppler imaging. Thickening and signal changes in the PF as well as oedema of adjacent soft tissues and bone marrow can be assessed on MRI. Radiographic findings of plantar fasciitis include PF thickening, cortical irregularities and abnormalities in the fat pad located deep below the PF. Plantar fibromatosis appears as well-demarcated, nodular thickenings that are iso-hypoechoic on ultrasound and show low-signal intensity on MRI. PF tears present with partial or complete fibre interruption on both ultrasound and MRI. Imaging description of further PF disorders, including xanthoma, diabetic fascial disease, foreign-body reactions and plantar infections, is detailed in the main text. Ultrasound and MRI should be considered as first- and second-line modalities for assessment of PF disorders, respectively. Indirect findings of PF disease can be ruled out on plain radiography.

Teaching Points

• PF disorders commonly cause heel pain and disability in the general population.

• Imaging is often required to confirm diagnosis or reveal concomitant injuries.

• Ultrasound and MRI respectively represent the first- and second-line modalities for diagnosis.

• Indirect findings of PF disease can be ruled out on plain radiography.