Magnetic resonance imaging findings in anterolateral impingement of the ankle

Impingement syndromes of the ankle and hindfoot

Ankle impingement refers to a chronic painful mechanical limitation of ankle motion caused by soft-tissue or osseous abnormality affecting the tibiotalar joint or extraarticular soft tissues. Impingement can be associated with a prior single traumatic event or repetitive microtrauma, often in an adolescent with anatomical predisposition. Impingement syndromes at the tibiotalar joint can be subdivided into anterior, anterolateral, anteromedial, posterior or posteromedial. Extraarticular impingement can consist of talocalcaneal or subfibular impingement. Impingement syndromes are just one possible etiology of persistent ankle pain, and although the diagnosis is often made or suspected clinically, the radiologist might be the first person to raise the possibility of the diagnosis or be called upon to provide support for the clinically suspected diagnosis. In this article I review the etiology, imaging findings and current treatment associated with these conditions.

Preoperative MRI is helpful but not sufficient to detect associated lesions in patients with chronic ankle instability

PURPOSE

The aim of this study was to determine the reliability and validity of preoperative magnetic resonance imaging (MRI) scans for the detection of additional pathologies in patients with chronic ankle instability (CAI) compared to arthroscopic findings.

METHODS

Preoperative MRI images of 30 patients were evaluated regarding articular and periarticular comorbidities and compared to intraoperative findings. The reliability of MRI was determined by calculating specificity, sensitivity, as well as positive and negative predictive values. The accuracy of the classification of cartilage lesions by Outerbridge and Berndt and Harty rating scales was determined by calculating the area under the receiver operating curve (AUC).

RESULTS

In total, 72 additional pathologies were found arthroscopically compared to 73 lesions gathered from MRI images. Sensitivity ranged from 89% for peroneal tendinopathy to 28% for additional ligamentous lesions. Specificity ranged from 100% for anterolateral impingement, loose bodies and peroneal tendinopathy to 38% for additional ligamentous lesions. For cartilage lesions, sensitivity was at 91% and specificity was at 55% for the Outerbridge grading scale. For the Berndt and Harty classification system, sensitivity was at 91% and specificity was at 28%. Correlation of additional pathologies ranged from weak (r s = 0.48; p = 0.02) to moderate results (r s = 0.67; p < 0.001).

CONCLUSION

CAI is associated with a high incidence of additional pathologies. In some cases, MRI delivers insufficient results, which may lead to misinterpretation of present comorbidities. MRI is a helpful tool for preoperative evaluation, but arthroscopy remains gold standard in the diagnosis of associated lesions in patients with CAI.

LEVEL OF EVIDENCE

III.

ACR Appropriateness Criteria® Chronic Ankle Pain

Chronic ankle pain is a common clinical problem whose cause is often elucidated by imaging. The ACR Appropriateness Criteria for chronic ankle pain define best practices of image ordering. Clinical scenarios are followed by the imaging choices and their appropriateness. The information is in ordered tables with an accompanying narrative explanation to guide physicians to order the right test. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Does antero-lateral ankle impingement exist?

Antero-lateral ankle impingement syndrome (ALAIS) is a well-established clinical entity that is a common consequence of ankle sprains. Injury to the anterior talo-fibular ligament plays a key role in the genesis of ALAIS. Arthroscopic antero-lateral synovectomy is the standard of care. However, this treatment approach may deserve to be challenged, as it does not include any procedure on the ligaments, despite the presence in some patients of lateral rotational micro-instability of the ankle, without objective laxity. Consequently, we reviewed current data on ALAIS and its links to ankle instability, from the dual perspective of diagnosis and treatment.

Current concepts review: Arthroscopic treatment of anterior ankle impingement

Anterior ankle impingement is a common cause of chronic ankle pain, particularly in athletic populations. Morris and McMurray provided the earliest descriptions of anterior impingement, coining the condition as "athlete's ankle" or "footballer's ankle". The pathology has since been a topic of considerable investigation and has been re-termed "anterior ankle impingement syndrome". Treatment with open surgery has provided good results historically, but at the price of significant complications. Advancements in ankle arthroscopy have decreased the risk of complication drastically and evidence in the literature indicates that anterior arthroscopy is an effective approach to treating osseous and soft tissue impingement. Effective clinical diagnosis and diagnostic imaging are critical for pre-surgical planning. Preoperative detection of anterior osteophytes has been correlated with outcomes. Factors such as joint space narrowing and large osteophytes may also influence outcomes. Therefore, a comprehensive understanding of diagnosis and surgical technique can influence patient outcomes, and patient expectations can be managed around prognostic indicators such as the presence of osteoarthritis. The purpose of this review is to discuss the etiology, clinical presentation, diagnosis, surgical technique, and postoperative rehabilitation of anteromedial and anterolateral anterior ankle impingement syndrome and to evaluate the evidence-based outcomes of arthroscopic management.

Ankle impingement syndromes: an imaging review

Ankle impingement syndromes encompass a broad spectrum of post-traumatic and chronic degenerative changes that present with pain on specific movements about the ankle joint. Both amateur and professional athletes are disproportionately affected by these conditions, and while conservative measures can potentially treat an impingement syndrome, definitive therapy is often alleviated surgically. Imaging (including conventional radiography, ultrasound, CT and MRI) plays an invaluable role in the diagnosis and pre-surgical work-up. An anatomically based classification system is useful in these syndromes, as the aetiology, sites of pathology and preferred treatment methods are similarly based on anatomic locations about the ankle. This review focuses on the anatomic locations, pathophysiology, imaging considerations and brief discussion of therapies for each of the major anatomic ankle impingement syndromes.

US in ankle impingement syndrome

Ankle impingement is a common condition occurring secondary to sprain or repeated microtrauma. Clinical symptoms are chronic pain located in the affected region and limited range of ankle motion. There are three types of ankle impingement syndrome: anterior impingement, which can be subdivided into anterolateral, anteromedial and purely anterior impingement; posterior impingement, which can be subdivided into posterior and posteromedial impingement; and calcaneal peroneal impingement which is secondary to planovalgus foot deformity. This paper evaluates physiological and clinical elements of these three types of ankle impingement syndrome as well as the role of ultrasound (US) imaging and US-guided treatment.

Ankle arthroscopy in a hanging position combined with hindfoot endoscopy for the treatment of concurrent anterior and posterior impingement syndrome of the ankle

The purpose of the present study was to evaluate the results of arthroscopic and endoscopic treatment of concurrent anterior and posterior ankle impingement with the patient in a prone position. From May 2009 to September 2010, 22 patients with simultaneously combined anterior and posterior ankle impingements underwent ankle arthroscopy in a prone position. Noninvasive ankle distraction was achieved by hanging the affected ankle on a shoulder-holding traction frame, followed by hindfoot endoscopy. The mean age at surgery was 22.6 (range 20 to 46) years. The mean follow-up duration was 15.4 (range 12 to 29) months. The American Orthopaedic Foot and Ankle Society scores and Foot Function Index were checked preoperatively and at the final follow-up visit. The mean American Orthopaedic Foot and Ankle Society score increased from 62.6 preoperatively to 86.0 at the final follow-up visit (p < .05). The Foot Function Index improved from 45.8 to 17.2 (p < .05). Of the 22 patients, 18 were very satisfied or satisfied with the results, 2 rated their results as fair, and 2 were dissatisfied. No complications related to ankle distraction in a hanging position occurred. Ankle arthroscopy with the patient in a prone position with the ankle hung on a shoulder-holding traction frame combined with hindfoot endoscopy provided a useful method for treating anterior and posterior ankle impingement that does not require changing the patient's position from supine to prone.

FS-3D-FISP for the diagnosis of ankle impingement syndrome and the evaluation of clinical outcomes of arthroscopic surgery

This study aimed to assess the diagnostic value of three types of MRI sequences and to observe the clinical outcomes of arthroscopy surgery for ankle joint impingement syndrome. Ankle joint impingement syndrome was confirmed by FSE-T2WI, FSE-PDWI, and FS-3D-FISP MRI in 23 patients with arthroscopically proven ankle impingement. All 23 patients underwent arthroscopic surgery and the ankle joint function was evaluated before, 1 week after and 6 months after the operation. The patients were followed-up for 12-64 months (average 28 months). There was no significant difference in ankle function score between preoperatively and 1 week postoperatively, but 86.96 % patients got overall excellent or good scores 6 months after the surgery, significantly higher than before the surgery. The FS-3D-FISP MRI exhibited a good consistency with arthroscopic examination and had higher sensitivity and specificity for the diagnosis of ankle impingement than FSE-T2WI and FSE-PDWI. In summary, arthroscopy surgery for ankle impingement syndrome has several advantages such as good efficacy, minimal trauma, quick recovery, and much less complications. The preoperative FS-3D-FISP MRI allows accurate diagnosis and positioning of ankle impingement syndrome.

Review of common and unusual causes of lateral ankle pain

Lateral ankle pain is a common clinical presentation having several important causes, including lateral ligament injury, peroneal tendon injury, sinus tarsi syndrome, and nerve entrapments. However, other causes should be kept in mind in patients with unusual patterns of pain or intractable symptoms. We present a review of common and some unusual causes of lateral ankle pain including a review of post-operative imaging findings following surgery for lateral ankle ligament and peroneal tendon injuries.

Ankle arthroscopy in children

INTRODUCTION

Arthroscopy of the ankle has gained acceptance as a procedure for diagnosing and treating chronic and post-traumatic ankle problems. The senior author's perception is that magnetic resonance imaging (MRI) under-diagnoses anterior soft tissue impingement lesions in children. The purpose of this study was retrospectively to analyse the outcome of ankle arthroscopy in the paediatric age group.

PATIENTS AND METHODS

Between March 2005 and September 2007, 23 children underwent ankle arthroscopy for post-traumatic pathology. The indications for arthroscopy were failure of non-operative treatment for at least 12 weeks or a grade 3 or 4 osteochondral defect (OCD) on imaging.

RESULTS

At arthroscopy, OCDs were visualised in 12 cases and impingement lesions were seen in 17 ankles. MRI was performed in 8 of these 12 cases and only 1 suggested the possibility of an impingement lesion. Of the 17 cases of impingement seen on arthroscopy, 12 reported mechanical symptoms preoperatively and 4 were unstable on examination under anaesthetic. Eighteen of the twenty-three patients had complete relief of symptoms at 3 months. Eighteen children who were evaluated at one-year follow up had a mean American Orthopaedic Foot and Ankle Society score of 87. 5 (range: 49-100).

CONCLUSIONS

Ankle arthroscopy has a successful outcome in paediatric patients and the results are comparable with those reported in adult series. MRI was found to be insensitive for the diagnosis of soft tissue impingement of the ankle.

Arthroscopic treatment of anterior ankle impingement

Anterior ankle impingement is a common cause of chronic ankle pain in the athletic population. Its cause can be either soft tissue or osseous in nature. Arthroscopic debridement results in favorable and reproducible outcomes. However, in the population in which ankle instability or narrowing of the ankle joint occur, outcomes may be less favorable.

Pathoanatomy of posterior ankle impingement in ballet dancers

Dance is a high performance athletic activity that leads to great numbers of injuries, particularly in the ankle region. One reason for this is the extreme range of ankle motion required of dancers, especially females in classical ballet where the en pointe and demi-pointe positions are common. These positions of maximal plantar flexion produce excessive force on the posterior ankle and may result in impingement, pain, and disability. Os trigonum and protruding lateral talar process are two common and well-documented morphological variations associated with posterior ankle impingement in ballet dancers. Other less well-known conditions, of both bony and soft tissue origins, can also elicit symptoms. This article reviews the anatomical causes of posterior ankle impingement that commonly affect ballet dancers with a view to equipping healthcare professionals for improved effectiveness in diagnosing and treating this pathology in a unique type of athlete.

MRI evaluation of anterolateral soft tissue impingement of the ankle

BACKGROUND

The usefulness of magnetic resonance imaging (MRI) has been questioned in evaluating patients with chronic ankle sprain pain. The purpose of this study was to determine the effectiveness and reliability of routine MR imaging in the diagnosis of anterolateral soft tissue impingement.

MATERIALS AND METHODS

Inclusion criteria required that the MR examinations be performed by the same musculoskeletal radiologist after the most recent scanner upgrade and using a dedicated ankle/hindfoot coil. The surgical and MRI reports of 24 patients who had an arthroscopic diagnosis of anterolateral soft tissue impingement of the ankle were tabulated and categorized. Unlike previous studies, sagittal T1 and Short Tau Inversion Recovery (STIR) images were used primarily in the diagnosis of these lesions.

RESULTS

Using this technique, we report a 78.9% accuracy in diagnosis, a sensitivity of 83.3% and a specificity of 78.6%. Fifty-eight percent of patients had an associated diagnosis, which in 33% of patients altered our surgical plan.

CONCLUSION

Although not indicated in all cases of anterolateral ankle impingement, we advocate the use of MR imaging in complicated clinical presentations where the exclusion of additional pathology in the ankle or subtalar joint, and the confirmation of anterolateral soft tissue impingement would be beneficial.

Imaging of impingement lesions in the ankle

Ankle impingement and instability are well-recognized complications of ankle sprain. Ankle impingement is an important cause of chronic ankle pain in active populations, particularly in the professional athlete. Depending on anatomical location and the structures involved, impingement syndromes are classified into anterolateral, anterior, posterior, posteromedial, and anteromedial types. Clinically, impingement syndromes are characterized by painful limitation of full-ankle movement. Ankle impingement results from repetitive subclinical trauma due to overuse injuries, which, in the subacute or chronic situation, lead to abnormal osseous and soft-tissue thickening within the ankle joint. Various imaging techniques can be used in the diagnosis of ankle impingement. Usually, radiography is the initial imaging technique performed to rule out bony trauma and identify potential anatomical bony abnormalities. Use of computed tomography and isotope bone scanning is largely superseded by magnetic resonance imaging, although with variable sensitivity and specificity. Arthrographic techniques, using computed tomography or magnetic resonance, are useful for exquisite demonstration of capsular recesses and synovial abnormalities. Imaging-guided injection techniques can be used in the management of impingement for pain ablation and to aid clinical diagnosis, especially in hind foot pain.

Ankle impingement syndromes

Acute or repetitive trauma to the ankle can result in painful restriction of movement caused by impingement of soft tissue and osseous structures. Ankle impingement syndromes are classified according to their anatomic relationship to the tibiotalar joint. This article reviews the relevant anatomy, etiology, and clinical features of ankle impingement syndromes, and demonstrates the potential imaging findings and discusses management of each for these conditions.

Ankle MRI for anterolateral soft tissue impingement: increased accuracy with the use of contrast-enhanced fat-suppressed 3D-FSPGR MRI

Objective

To validate the use of contrast-enhanced (CE) fat-suppressed three-dimensional (3D) fast gradient-recalled acquisition in the steady state with radiofrequency spoiling (FSPGR) magnetic resonance imaging (MRI) for the diagnosis of anterolateral soft tissue impingement of the ankle, as compared to the use of routine ankle MRI.

Materials and Methods

Contrast-enhanced fat-suppressed 3D-FSPGR MRI and routine MRI scans were retrospectively reviewed for 45 patients with arthroscopically proven anterolateral impingement. In addition, scans were reviewed in 45 control subjects with diagnoses other than impingement. Two radiologists independently reviewed the two sets of images in random order. Using areas (Az) under the receiver operating characteristic curve (ROC), we compared the depiction of anterolateral soft tissue impingement in the two sets of images.

Results

The overall accuracy for lesion characterization was significantly higher (p < 0.05) using the CE fat-suppressed 3D-FSPGR MR images (Az = 0.892 and 0.881 for reader 1 and 2, respectively) than using the routine MR images (Az = 0.763 and 0.745). The use of CE fat-suppressed 3D-FSPGR MRI enhanced impingement depiction in most cases. However, in cases with a thickened non-enhancing scar or joint effusion, the routine images better depicted a soft tissue mass that intruded into anterolateral gutter than the CE images.

Conclusion

The use of CE fat-suppressed 3D-FSPGR MRI of the ankle allows a more accurate assessment of anterolateral soft tissue impingement of the ankle, as compared to the use of routine MRI.

Imaging evaluation of chronic ankle and hindfoot pain in athletes

Acute ankle and hindfoot injuries are common in athletes and typically are treated conservatively. Persistent pain that has not responded to appropriate conservative treatment and prevents the patient from returning to play is more problematic for the athlete and the treating sports clinician. Making a specific clinical and imaging diagnosis in these patients can be quite challenging. This article discusses the imaging evaluation of chronic ankle and hindfoot pain related to osseous and soft-tissue injuries in athletes. MR imaging is the preferred imaging modality in most of the presented cases.

Anterolateral ankle impingement: findings and diagnostic accuracy with ultrasound imaging

OBJECTIVE

The objective was to evaluate the findings and diagnostic accuracy of ultrasound in antero-lateral ankle impingement (ALI) with clinical and arthroscopic correlation.

DESIGN AND PATIENTS

Seventeen elite footballers with chronic ankle pain were referred for ultrasound with a clinical diagnosis of ALI (n = 8) or a control condition (n = 9; lateral mechanical instability, osteochondral defect, intra-articular bodies and osteoarthritis). Ultrasound examination included the antero-lateral gutter for abnormal synovial tissue (synovitic lesion), lateral ligament integrity, tibiotalar joint and osseous spurs of the distal tibia and talus. Ultrasound findings were correlated with subsequent arthroscopic appearance.

RESULTS

Ultrasound examination detected a synovitic mass in the antero-lateral gutter in all 8 footballers with clinical ALI (100%) and in 2 patients with a control diagnosis (22%). Arthroscopic correlation of antero-lateral synovitis and fibrosis was present in all 10 cases (100%). The synovitic lesion was seen at ultrasound as a nodular soft tissue mass of mixed echogenicity within the antero-lateral gutter, which extruded anteriorly with manual compression of the distal fibula against the tibia. Increased blood supply was detected using power Doppler imaging in only 1 patient. The synovitic lesion measured >10 mm in its maximum dimension in 7 footballers with clinical ALI and <10 mm in the control group. Additional ultrasound findings in patients with abnormal antero-lateral synovial tissue included an anterior talofibular ligament injury in all patients (n = 10), a tibiotalar joint effusion (n = 6) and osseous spurs (n = 4). Antero-lateral synovitic tissue was accurately identified at ultrasound in the absence of an effusion (n = 4). No synovitic lesion was detected at ultrasound or arthroscopy in the remaining 7 patients with a control diagnosis.

CONCLUSION

Ultrasound is accurate in detecting synovitic lesions within the antero-lateral gutter, demonstrating associated ligamentous injuries and in differentiating soft tissue from osseous impingement. Synovitic lesions in two control patients suggest that abnormal antero-lateral soft tissue does not necessarily imply the presence of symptomatic ALI. Synovitic lesions in excess of 10 mm were associated with symptoms. Ultrasound will not demonstrate osteocartilaginous lesions or stress fractures and may overlook some loose bodies. Ultrasound findings together with clinical correlation can be used to direct arthroscopic examination and surgical debridement.

MRI appearance of surgically proven abnormal accessory anterior-inferior tibiofibular ligament (Bassett's ligament)

OBJECTIVE

A thickened accessory anterior-inferior tibiofibular ligament (Bassett's ligament) of the ankle can be a cause of ankle impingement. Its imaging appearance is not well described. The purpose of this study was to determine if the ligament could be identified on magnetic resonance imaging (MRI), to determine associated abnormalities, and to determine if MRI could be used to differentiate normal from abnormal.

MATERIALS AND METHODS

Eighteen patients with a preoperative ankle MRI and an abnormal Bassett's ligament reported at surgery were found retrospectively. A separate cohort of 18 patients was selected as a control population. The presence of Bassett's ligament and its thickness were noted. The integrity and appearance of the lateral ankle ligaments, talar dome cartilage, and anterolateral gutter were also noted.

RESULTS

In 34 of the 36 cases (94%), Bassett's ligament was identified on MRI. The ligament was seen in all three imaging planes and most frequently in the axial plane. The mean thickness of the ligament in the surgically abnormal cases was 2.37 mm, compared with 1.87 mm in the control with a p value=0.015 (t test). Nine of the 18 abnormal cases (50%) had talar dome cartilage lesions as a result of contact with the ligament at surgery, with only 3 cases of high-grade defects seen on MRI. Fourteen of the 18 abnormal cases (78%) had of synovitis or scarring in the lateral gutter at surgery, with only 5 cases with scarring seen on MRI. The anterior-inferior tibiofibular ligament was abnormal or torn in 8 of the 18 abnormal cases (44%) by MRI and confirmed in only 3 cases at surgery.

DISCUSSION

Bassett's ligament can be routinely identified on MRI and was significantly thicker in patients who had it resected at surgery. An abnormal Bassett's ligament is often present in the setting of a normal anterior-inferior tibiofibular ligament. The cartilage abnormalities and synovitis associated with an abnormal Bassett's ligament are poorly detected by conventional MRI.

Impingement syndromes of the ankle

Ankle impingement syndromes are categorised according to their anatomical site around the tibiotalar joint. Anterolateral, anterior and posterior ankle impingement has been extensively described in the orthopaedic and radiology literature with more recent studies describing posteromedial and anteromedial impingement. This article aims to demonstrate the potential spectrum of imaging findings for each ankle impingement syndrome as well as the relative contributions of ultrasound and MR imaging for diagnosis and image-guided treatment.

Chronic tibiofibular syndesmosis injury of ankle: evaluation with contrast-enhanced fat-suppressed 3D fast spoiled gradient-recalled acquisition in the steady state MR imaging

PURPOSE

To retrospectively determine the accuracy of coronal contrast material-enhanced fat-suppressed three-dimensional (3D) fast spoiled gradient-recalled acquisition in the steady state (SPGR) magnetic resonance (MR) imaging, as compared with that of routine transverse MR imaging, in the assessment of distal tibiofibular syndesmosis injury, with arthroscopy as the reference standard.

MATERIALS AND METHODS

The review board of the College of Medicine in Yonsei University approved this study; informed consent was waived. The study group comprised 45 patients (26 men, 19 women; mean age, 32.1 years; range, 18-58 years) with a chronic ankle injury who had undergone MR imaging and arthroscopic surgery. Three independent readers retrospectively reviewed the two sets of MR images (one set of gadolinium-enhanced 3D fast SPGR images and one set of routine T1-, T2-, and intermediate-weighted images). Scores from 1 to 5 in increasing order of the probability of injury were assigned to both sets. Arthroscopy was the reference standard. Syndesmotic recess height was measured on contrast-enhanced images. The two sets of images were compared for diagnostic performance with receiver operating characteristic (ROC) analysis. Dissection and histologic examination of six cadaveric ankles was performed to assess the syndesmotic area and ascertain the enhancing structure at MR imaging.

RESULTS

At arthroscopy, syndesmotic injury was found in 24 ankles but not in 21 ankles. Areas under the ROC curve were significantly higher for the contrast-enhanced images (P<.05). The contrast-enhanced set showed higher accuracy, sensitivity, and specificity compared with the routine set for the assessment of syndesmosis injury. Mean syndesmotic recess height was significantly greater (P<.05) in patients with syndesmotic injury. Dissection and histologic examination revealed a highly vascular synovial fold in the syndesmotic area that is expected to enhance at MR imaging.

CONCLUSION

In the assessment of chronic syndesmosis injury, coronal gadolinium-enhanced fat-suppressed 3D fast SPGR MR images were more sensitive, specific, and accurate than routine MR images.

Magnetic resonance arthrography

For decades, fluoroscopic arthrography was the only method available to image a joint with contrast enhancement. Advances in CT led to the natural development of CT arthrography. Development of MRI and its capability for multiplanar imaging led to direct magnetic resonance arthrography (MRA). This technique has been performed since 1987 and has surpassed CT arthrography in popularity in the United States. Indirect MRA developed subsequently to offer a less invasive alternative. This article presents an overview of direct MRA and addresses joint-specific issues regarding direct MRA. An overview of indirect MRA also is provided.

MR-imaging of anterior tibiotalar impingement syndrome: Agreement, sensitivity and specificity of MR-imaging and indirect MR-arthrography

OBJECTIVE

To clarify the role of MR-imaging in the diagnosis of anterior ankle impingement syndromes.

MATERIALS AND METHODS

We prospectively examined 51 consecutive patients with chronic ankle pain by MR-imaging. Arthroscopy was performed in 29 patients who previously underwent non-enhanced MR-imaging; in 11 patients, indirect MR-arthrography additionally was performed. MR-examinations were correlated with clinical findings; MR and arthroscopy scores were statistically compared, agreement was measured.

RESULTS

Arthroscopy demonstrated granulation tissue in the lateral gutter (38%) and anterior recess (31%), lesions of the anterior tibiofibular (31%) and the anterior talofibular ligament (21%) as well as intraarticular bodies (10%). Stenosing tenosynovitis and a ganglionic cyst were revealed as extraarticular causes for chronic ankle pain by MR-examination (17%). Agreement of MR-imaging and arthroscopy was fair for the anterior talofibular ligament and the anterior joint cavity (kappa 0.40). Major discrepancy was found for non-enhanced MR scans (kappa 0.49) when compared with indirect MR-arthrography (kappa 0.03) in the anterior cavity. The sensitivity for lesions of the anterior talofibular and calcaneofibular ligament and the anterior cavity (0.91-0.87) detected by MR-imaging was superior in comparison to lesions of the anterior tibiofibular ligament and anteromedial cavity (0.50-0.24).

CONCLUSION

MR-imaging provides additional information about the mechanics of chronic ankle impingement rather than an accurate diagnosis of this clinical entity. The method is helpful in differentiating extra- from intra-articular causes of ankle impingement. Indirect MR-arthrography has little or no additional value in patients with ankle impingement syndrome.

Ankle MR Arthrography: How, Why, When

MR arthrography has become an important tool for the assessment of a variety of ankle disorders. MR arthrography may facilitate the evaluation of patients with suspected intra-articular pathology in whom conventional MR imaging is not sufficient for an adequate diagnosis and be useful for therapy planning. MR arthrography is valuable in the evaluation of ligamentous injuries, impingement syndromes, cartilage lesions, osteochondral lesions of the talus, loose bodies, and several synovial joint disorders. Indirect MR arthrography is a useful adjunct to conventional MR imaging and may be preferable to direct MR arthrography in cases in which an invasive procedure is contraindicated or when fluoroscopy is not available.

Soft tissue impingement syndrome of the ankle: diagnostic efficacy of MRI and clinical results after arthroscopic treatment

BACKGROUND

Soft-tissue impingement syndrome is now increasingly being recognized as a significant cause of chronic ankle pain. The aim of this study was to investigate the diagnostic accuracy of contrast-enhanced, fat-suppressed, three-dimensional (3D), fast-gradient-recalled acquisition in the steady state with radio-frequency-spoiling (CE 3D-FSPGR) magnetic resonance imaging (MRI), and to evaluate the clinical outcome of arthroscopic treatment of soft-tissue impingement associated with the ankle trauma.

METHODS

This study reviewed 38 patients who had preoperative MRI and arthroscopic treatment of chronic ankle pain after trauma. The CE 3D-FSPGR MRI was used to evaluate the chronic ankle pain, and the American Orthopedic Foot and Ankle Society (AOFAS) Ankle-Hindfoot Score was used to evaluate the clinical results after arthroscopic treatment.

RESULTS

The CE 3D-FSPGR MRI showed a sensitivity of 91.9%, a specificity of 84.4%, and an accuracy of 87.5% in diagnosing synovitis and soft tissue impingement. All patients had excellent or good outcomes after arthroscopic debridement.

CONCLUSION

The results of this study suggest that a preoperative fat-suppressed CE 3D-FSPGR MRI is highly beneficial in diagnosing synovitis and soft-tissue impingement and that arthroscopic debridement of the synovitis or soft-tissue impingement has a good clinical outcome.

Diagnosis and Management of the Painful Ankle/Foot. Part 2: Examination, Interpretation, and Management

Diagnosis, interpretation, and subsequent management of ankle/foot pathology can be challenging to clinicians. A sensitive and specific physical examination is the strategy of choice for diagnosing selected ankle/foot injuries and additional diagnostic procedures, at considerable cost, may not provide additional information for clinical diagnosis and management. Because of a distal location in the sclerotome and the reduced convergence of afferent signals from this region to the dorsal horn of the spinal cord, pain reference patterns are low and the localization of symptoms is trustworthy. Effective management of the painful ankle/foot is closely linked to a tissue-specific clinical examination. The examination of the ankle/foot should include passive and resistive tests that provide information regarding movement limitations and pain provocation. Special tests can augment the findings from the examination, suggesting compromises in the structural and functional integrity of the ankle/foot complex. The weight bearing function of the ankle/foot compounds the clinician's diagnostic picture, as limits and pain provocation are frequently produced only when the patient attempts to function in weight bearing. As a consequence, clinicians should consider this feature by implementing numerous weightbearing components in the diagnosis and management of ankle/foot afflictions. Limits in passive motion can be classified as either capsular or non-capsular patterns. Conversely, patients can present with ankle/foot pain that demonstrates no limitation of motion. Bursitis, tendopathy, compression neuropathy, and instability can produce ankle/foot pain that is challenging to diagnose, especially when they are the consequence of functional weight bearing. Numerous non-surgical measures can be implemented in treating the painful ankle/foot, reserving surgical interventions for those patients who are resistant to conservative care.

Multi-fasciculated anterior talo-fibular ligament: reassessment of normal findings

The aims of this study were to (a) provide an accurate description of the anterior talo-fibular ligament (ATFL) multifasciculated feature by means of cadaver study, and (b) to further delineate contour and signal variations on MR images related to this feature in a group of asymptomatic subjects. After MR imaging, three cadaveric feet were frozen and cut in the coronal plane. The ATFL were harvested and sent to pathology. Another cadaveric foot was dissected. The MR imaging was performed in 3 healthy volunteers and 19 patients without pathology of the ATFL. For both cadaveric feet and subjects, MR imaging protocol consisted of axial and coronal proton-density (PD) and T2-weighted turbo-spin-echo (TSE) sequences (TR/TE: 3500 ms/17-119 ms). On MR images, ATFL signal and fascicle numbers were assessed, respectively, in the axial and coronal planes. Gross anatomy and pathology confirmed the ATFL bifasciculated aspect. On cadaveric coronal MR images, 3 of 4 ATFLs were bifasciculated and one of four was striated. On patients' coronal MR images, 2 of 22 of the ATFL were monofasciculated, 12 of 22 bifasciculated, and 8 of 22 striated. On axial MR images, 16 of 22 of the ATFL demonstrated a low signal intensity and 8 of 22 an intraligamentous subtle increased signal intensity. Two of 22 of the ATFL had contour irregularities. Isolated anterior talo-fibular intraligamentous signal abnormalities or contour irregularities on axial PD and T2-weighted MR images with an otherwise normal ATFL aspect on coronal MR images and no other MRI criteria for ankle sprain may reflect normal anatomy.

Synovitis and soft tissue impingement of the ankle: Assessment with enhanced three-dimensional FSPGR MR imaging

PURPOSE

To assess soft tissue impingement as well as synovitis of the ankle associated with trauma by using contrast-enhanced (CE), fat-suppressed, three-dimensional, fast gradient-recalled acquisition in the steady state with radiofrequency spoiling (FSPGR) magnetic resonance (MR) imaging.

MATERIALS AND METHODS

A total of 36 patients who had had chronic ankle pain associated with a traumatic injury undertook fat-suppressed CE three-dimensional FSPGR MR imaging and then arthroscopy of the ankle. The ankle joint was divided into four compartments by anatomic details: the anterolateral gutter, anteromedial gutter, anterior recess, and posterior recess. Synovial enhancement was graded as follows: grade I, no enhancement; grade II, linear enhancement; grade III, focal nodular enhancement; and grade IV, irregular nodular enhancement. MR grading of the synovial enhancement (synovitis, grade III or IV; soft tissue impingement, grade III or IV with its intrusion from the capsular reflection) was compared with arthroscopic findings. A control study of twenty asymptomatic ankles was done for determining enhancement. Arthroscopy confirmed synovitis in 47 compartments of 27 patients. Of the 27 patients, 15 revealed soft tissue impingement in 17 compartments.

RESULTS

For the assessment of synovitis, fat-suppressed CE three-dimensional FSPGR MR imaging had an accuracy of 72.9%, sensitivity of 91.5%, and specificity of 63.9%; whereas for that of soft tissue impingement it had an accuracy of 94.4%, sensitivity of 76.5%, and specificity of 96.9%. All of the asymptomatic subjects showed grade I (81%) or II (19%) synovial enhancement.

CONCLUSION

Fat-suppressed CE three-dimensional FSPGR MR imaging was sensitive for the evaluation of synovitis of the ankle associated with trauma, whereas it was specific for soft tissue impingement evaluation.

Soft-tissue and osseous impingement syndromes of the ankle: role of imaging in diagnosis and management

Soft-tissue and osseous impingement syndromes of the ankle can be an important cause of chronic pain, particularly in the professional athlete. The main impingement syndromes are anterolateral, anterior, anteromedial, and posterior impingement. These conditions arise from initial ankle injuries, which, in the subacute or chronic situation, lead to development of abnormal osseous and soft-tissue thickening within the ankle joint. The relative contributions of the osseous and soft-tissue abnormalities are variable, but whatever component is dominant there is physical impingement and painful limitation of ankle movement. Conventional radiography is usually the first imaging technique performed and allows assessment of any potential bone abnormality, particularly in anterior and posterior impingement. Computed tomography (CT) and isotope bone scanning have been largely superseded by magnetic resonance (MR) imaging, but the accuracy and role of MR imaging in assessment of possible ankle impingement have not been clearly established. MR imaging can demonstrate osseous and soft-tissue edema in anterior or posterior impingement. Studies of conventional MR imaging have produced conflicting sensitivities and specificities in assessment of anterolateral impingement. CT and MR arthrographic techniques allow the most accurate assessment of the capsular recesses, albeit with important limitations in diagnosis of clinical impingement syndromes.

MR arthrography of the lower extremity

MR arthrography by virtue of its ability accurately to demonstrate intra-articular structures and abnormalities of these structures has become an important tool for the evaluation of a variety of articular disorders. Although not necessary in all patients, MR arthrography may facilitate the evaluation of patients with suspected intra-articular pathology in whom conventional MRI is not sufficient for an adequate therapy planning. MR arthrography combines the advantages of arthrography, like joint distention and delineation of intra-articular structures, with the superior spatial resolution of MRI. This technique improves diagnostic confidence, particularly in the assessment of subtle lesions and of complex anatomic structures. MR arthrography is of high value in the evaluation of osteochondral defects, loose bodies, previously operated menisci, and acetabular labral lesions.

MRI of soft tissue disorders of the ankle

In summary, MRI has become the dominant imaging modality for assessing soft tissue disorders of the ankle. It is useful in evaluating patients with acute or chronic ankle pain or instability, and for diagnosis and staging of soft tissue mass lesions. MRI often provides information that is essential to treatment planning of a variety of traumatic, degenerative, and neoplastic lesions.

Anteromedial impingement of the ankle: using MR arthrography to assess the anteromedial recess

OBJECTIVE

Our objective was to describe the appearance of the anteromedial tibiotalar joint on MR arthrography in patients with clinically and arthroscopically confirmed anteromedial impingement.

CONCLUSION

Anteromedial impingement of the ankle is now being recognized in the orthopedic literature as a distinct entity. MR arthrographic findings of anteromedial impingement include capsular and synovial soft-tissue thickening anterior to the tibiotalar ligaments and any associated osseous abnormality. Although anteromedial impingement is uncommon compared with other impingement syndromes of the ankle, the radiologist should be aware of the diagnosis and possible findings on cross-sectional imaging.

Anterolateral ankle impingement: mr arthrographic assessment of the anterolateral recess

PURPOSE

To determine the accuracy of magnetic resonance (MR) arthrography in assessing the anterolateral recess of the ankle.

MATERIALS AND METHODS

Thirty-two patients with chronic ankle pain prospectively underwent gadolinium-enhanced MR arthrography of the tibiotalar joint. All underwent clinical examination and were included if anterolateral impingement (n = 13) or a control condition (n = 19; suspected osteochondral defect, intraarticular bodies, instability, osteoarthritis) was diagnosed. MR imaging included transverse and coronal T1-weighted and sagittal T2-weighted imaging sequences. Images were prospectively analyzed by two readers blinded to the clinical diagnosis. The anterolateral gutter contour was assessed. MR arthrographic findings were correlated with subsequent arthroscopic appearances.

RESULTS

MR arthrographic assessment of the anterolateral soft tissues had an accuracy of 97%, sensitivity of 96%, specificity of 100%, negative predictive value of 89%, and positive predictive value of 100%. Accuracy was 100% with clinical anterolateral impingement, with an arthroscopically confirmed abnormality in 12 cases and a normal appearance in one. Anterolateral soft-tissue thickening was identified at MR arthrography in 11 control cases, with arthroscopic confirmation in all. The remaining cases had normal appearances, with an arthroscopic soft-tissue abnormality in one case and a normal appearance in seven.

CONCLUSION

MR arthrography of the tibiotalar joint is accurate in assessing the anterolateral recess of the ankle.

From the RSNA Refresher Courses. Radiological Society of North America. MR imaging of the ankle and foot

Magnetic resonance (MR) imaging has opened new horizons in the diagnosis and treatment of many musculoskeletal diseases of the ankle and foot. It demonstrates abnormalities in the bones and soft tissues before they become evident at other imaging modalities. The exquisite soft-tissue contrast resolution, noninvasive nature, and multiplanar capabilities of MR imaging make it especially valuable for the detection and assessment of a variety of soft-tissue disorders of the ligaments (eg, sprain), tendons (tendinosis, peritendinosis, tenosynovitis, entrapment, rupture, dislocation), and other soft-tissue structures (eg, anterolateral impingement syndrome, sinus tarsi syndrome, compressive neuropathies [eg, tarsal tunnel syndrome, Morton neuroma], synovial disorders). MR imaging has also been shown to be highly sensitive in the detection and staging of a number of musculoskeletal infections including cellulitis, soft-tissue abscesses, and osteomyelitis. In addition, MR imaging is excellent for the early detection and assessment of a number of osseous abnormalities such as bone contusions, stress and insufficiency fractures, osteochondral fractures, osteonecrosis, and transient bone marrow edema. MR imaging is increasingly being recognized as the modality of choice for assessment of pathologic conditions of the ankle and foot.