Injury of the tibiofibular syndesmosis: value of MR imaging for diagnosis

Arthroscopic Grading of Injuries of the Inferior Tibiofibular Syndesmosis

The objective of this study was to describe the technical details of performing a newly developed arthroscopic grading of inferior tibiofibular syndesmosis injuries. Arthroscopy is emerging as the gold standard for evaluating painful, unstable ankles. The inferior tibiofibular syndesmosis contributes substantially to disorders of the ankle. However, no structured grading system exists that would help surgeons evaluate injuries of the syndesmosis. Seventy-eight patients with pain or instability symptoms in the ankle were arthroscopically evaluated for syndesmosis injury. The lesions were graded according to the prospectively developed protocol. More than 61% of the patients had syndesmosis disruptions of various grades affecting the anterior/posterior ligaments or both ligaments. Fourteen patients had anterior ligament disruptions whereas 4 patients had posterior lesions; another 7 patients had both ligaments asymmetrically injured. Eighteen of the 78 patients had symmetric grade 1 lesions, and 5 had grade 2 lesions. More than half of chronic ankle pain cases have syndesmotic lesions. Symmetrical lesions of the anterior and posterior ligaments predominate, followed by isolated anterior ligament disruptions. The proposed grading system for inferior tibiofibular syndesmosis disruptions serves as a guide to systematic documentation of injuries of the syndesmosis.

Arthroscopic Deltoid Repair: A Technical Tip

Deltoid ligament repair can be challenging, and implementation of an arthroscopic method can be useful in terms of minimizing morbidity associated with open dissection, as long as the repair is effective and durable. In this brief report, we describe a method of arthroscopic deltoid ligament repair that we have found to be useful.

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.

Imaging in syndesmotic injury: a systematic literature review

OBJECTIVES

To give a systematic overview of current diagnostic imaging options for assessment of the distal tibio-fibular syndesmosis.

MATERIALS AND METHODS

A systematic literature search across the following sources was performed: PubMed, ScienceDirect, Google Scholar, and SpringerLink. Forty-two articles were included and subdivided into three groups: group one consists of studies using conventional radiographs (22 articles), group two includes studies using computed tomography (CT) scans (15 articles), and group three comprises studies using magnet resonance imaging (MRI, 9 articles).The following data were extracted: imaging modality, measurement method, number of participants and ankles included, average age of participants, sensitivity, specificity, and accuracy of the measurement technique. The Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool was used to assess the methodological quality.

RESULTS

The three most common techniques used for assessment of the syndesmosis in conventional radiographs are the tibio-fibular clear space (TFCS), the tibio-fibular overlap (TFO), and the medial clear space (MCS). Regarding CT scans, the tibio-fibular width (axial images) was most commonly used. Most of the MRI studies used direct assessment of syndesmotic integrity. Overall, the included studies show low probability of bias and are applicable in daily practice.

CONCLUSIONS

Conventional radiographs cannot predict syndesmotic injuries reliably. CT scans outperform plain radiographs in detecting syndesmotic mal-reduction. Additionally, the syndesmotic interval can be assessed in greater detail by CT. MRI measurements achieve a sensitivity and specificity of nearly 100%; however, correlating MRI findings with patients' complaints is difficult, and utility with subtle syndesmotic instability needs further investigation. Overall, the methodological quality of these studies was satisfactory.

The predictive value of MRI in the syndesmotic instability of ankle fracture

OBJECTIVE

Although many types of ankle fracture can be combined with syndesmosis injury, preoperative imaging studies rarely reveal instability of the syndesmosis. This study assessed the use of magnetic resonance imaging (MRI) for syndesmotic instability in patients with unstable ankle fracture.

METHODS

A total of 74 patients who were treated for Lauge-Hansen supination external rotation/Weber B type fracture or pronation external rotation/Weber C type fracture and who underwent MRI for preoperative assessment were enrolled. The MRI findings of the syndesmotic ligament and the results of an intraoperative stress test were evaluated.

RESULTS

Twenty-six patients had a positive result on the intraoperative stress test for syndesmotic instability. The MRI findings of the syndesmotic ligaments revealed that complete tear of the posterior inferior tibiofibular ligament (PITFL) was the most reliable predictor of syndesmotic instability (sensitivity, 74%; specificity, 78%; positive predictive value, 54%). Interobserver agreement for the intraoperative stress test and MRI assessment was excellent, except for the MRI findings of the interosseous ligament (62% agreement; kappa, 0.3).

CONCLUSIONS

Complete tear of the PITFL on MRI has additional diagnostic value for syndesmotic instability in ankle fracture. However, because the sensitivity might not be sufficient to justify the costs associated with MRI, cost-effectiveness should be considered.

A Radiographic Dye Method for Intraoperative Evaluation of Syndesmotic Injuries

BACKGROUND

The Chertsey test has been recently defined as an intraoperative test for the detection of the syndesmotic injuries by the application of intra-articular contrast. However, no study has investigated the reliability and comparative analysis of the Chertsey test. The purpose of this study was to explore the diagnostic accuracy of the Chertsey test in predicting syndesmosis instability of the injured ankle, with correlation to preoperative computed tomography (CT) findings.

METHODS

A total of 39 patients who were operated on due to the unilateral ankle fracture and had no complaint on the contralateral ankle joint were included in the study. An intraoperative Chertsey test was performed on all ankle fractures and bilateral ankle CT was obtained preoperatively. Ankles were classified as Chertsey +, Chertsey -, and contralateral control group. The morphology categorization, width, and volume of the syndesmotic region were measured on axial images of the CT. Mann-Whitney U test was used to compare the data. Intraobserver and interobserver agreements were accessed by calculating the intraclass correlation coefficient (ICC) for radiologic parameters and the Chertsey test.

RESULTS

The Chertsey test was positive in 13 (33.3%) of 39 ankle fractures. Patients with a positive Chertsey test showed a significant increase in syndesmotic width and volume compared with Chertsey - and control group. However, there was no significant difference between Chertsey - and the control group. All the ICC values were excellent for both radiologic measurements and test.

CONCLUSION

The Chertsey test is a reliable and useful test that can be used intraoperatively in the diagnosis of syndesmotic injuries.

LEVEL OF EVIDENCE

III, comparative series.

The effect of ankle distraction on arthroscopic evaluation of syndesmotic instability: A cadaveric study

BACKGROUND

To assist with visualization, orthopaedic surgeons often apply ankle distraction during arthroscopic procedures. The study aimed to investigate whether ankle distraction suppresses fibular motion in cadaveric specimens with an unstable syndesmotic injury.

METHODS

Fourteen fresh-frozen above knee specimens underwent arthroscopic assessment with 1) intact ligaments, 2) after sectioning of the anterior inferior tibiofibular ligament, the interosseous ligament, and the posterior inferior tibiofibular ligament, and 3) after sectioning of the deep and superficial deltoid ligament. In all scenarios, the lateral hook test, anterior-posterior hook test, and posterior-anterior hook test were applied. Each test was performed with and without ankle distraction. Coronal plane anterior and posterior tibiofibular diastasis as well as sagittal plane tibiofibular translation due to the applied load were arthroscopically measured.

FINDINGS

Tibiofibular diastasis in the coronal plane, as measured at both the anterior and posterior third of the incisura, was found to be significantly less when ankle distraction was applied, as compared to arthroscopic evaluation in the absence of distraction. In contrast, measurement of sagittal plane tibiofibular translation was not affected by ankle distraction.

INTERPRETATION

Since arthroscopic findings of syndesmotic instability are subtle the differential values of the syndesmotic measurements taken on and off distraction are clinically relevant. To optimally assess syndesmotic instability one should evaluate the syndesmosis without distraction or focus on fibular motion in the sagittal plane when distraction is required.

Effect of Sequential Sectioning of Ligaments on Syndesmotic Instability in the Coronal Plane Evaluated Arthroscopically

BACKGROUND

Arthroscopic evaluation of the syndesmosis allows direct visualization of syndesmotic instability. The purpose of this study was to determine the minimum degree of ligamentous injury necessary to destabilize the syndesmosis in the coronal plane when assessed arthroscopically and pinpoint where such instability should be measured within the incisura.

METHODS

Fourteen cadaveric specimens were divided into 2 groups and arthroscopically assessed first with the syndesmosis intact and then following serial differential ligamentous transection. Group 1 (n = 7): anterior-inferior tibiofibular (AITFL), interosseous (IOL), posterior-inferior tibiofibular (PITFL), and deltoid (DL) ligament. Group 2 (n = 7): PITFL-IOL-AITFL-DL. At each step, a standard 100-N lateral hook test was applied and tibiofibular coronal plane diastasis measured arthroscopically at both the anterior and posterior third of the incisura. These measurements were in turn compared with those of the stressed intact ligamentous state.

RESULTS

There was no significant syndesmotic instability measured at either the anterior or posterior margin of the incisura after transection of a singular ligament (AITFL or PITFL) or after the IOL was additionally transected. Diastasis at the posterior margin was significantly increased when all syndesmotic ligaments were sectioned (group 1: P = .018; group 2: P = .008), but this was not noted along the anterior margin. Diastasis at the anterior margin reached significance only with complete transection of syndesmosis and DL (group 1: P < .001; group 2: P = .044).

CONCLUSION

Under arthroscopic evaluation, the syndesmosis becomes unstable in the coronal plane only when all syndesmotic ligaments are transected, which should preferentially be measured at the posterior margin of the incisura. Anteriorly, diastasis becomes apparent only with addition of DL disruption, although this added finding may aid in diagnosis of occult deltoid injury.

CLINICAL RELEVANCE

AITFL, IOL, and PITFL need to be injured to produce coronal plane syndesmotic instability. Arthroscopic assessment of such instability should occur along the posterior margin of the incisura. When they exist, similar findings anteriorly suggest concomitant deltoid injury.

Management of syndesmotic injuries of the ankle

Injuries to the tibioperoneal syndesmosis are more frequent than previously thought and their treatment is essential for the stability of the ankle mortise.

Recognition of these lesions is essential to avoid long-term morbidity.

Diagnosis often requires complete history, physical examination, weight-bearing radiographs and MRI.

Treatment-oriented classification is mandatory.

It is recommended that acute stable injuries are treated conservatively and unstable injuries surgically by syndesmotic screw fixation, suture-button dynamic fixation or direct repair of the anterior inferior tibiofibular ligament.

Subacute injuries may require ligamentoplasty and chronic lesions are best treated by syndesmotic fusion.

However, knowledge about syndesmotic injuries is still limited as recommendations for surgical treatment are only based on level IV and V evidence.

Cite this article: EFORT Open Rev 2017;2:403–409. DOI: 10.1302/2058-5241.2.160084

Advanced MRI Techniques for the Ankle

OBJECTIVE

The purposes of this article are to present a state-of-the-art routine protocol for MRI of the ankle, to provide problem-solving tools based on specific clinical indications, and to introduce principles for the implementation of ultrashort echo time MRI of the ankle, including morphologic and quantitative assessment.

CONCLUSION

Ankle injury is common among both athletes and the general population, and MRI is the established noninvasive means of evaluation. The design of an ankle protocol depends on various factors. Higher magnetic field improves signal-to-noise ratio but increases metal artifact. Specialized imaging planes are useful but prolong acquisition times. MR neurography is useful, but metal reduction techniques are needed whenever a metal prosthesis is present. An ultrashort echo time sequence is a valuable tool for both structural and quantitative evaluation.

Acute syndesmotic instability in ankle fractures: A review

Ankle fractures are among the most common fracture types, and 10% of all ankle fractures lead to accessory syndesmotic injury. An injury that is challenging in every respect is syndesmotic instability. Since the range of diagnostic techniques and the therapeutic options is extensive, it still is a controversial subject, despite the abundance of literature. This review aimed to summarize the current knowledge on syndesmotic instability in ankle fractures and to formulate some recommendations for clinical practice. Chronic instability and the operative osseous treatment of ankle fractures are not part of this review.

Arthroscopic Correlates of Subtle Syndesmotic Injury

BACKGROUND

Arthroscopic criteria for identifying syndesmotic disruption have been variable and subjective. We aimed to quantify syndesmotic disruption arthroscopically using a standardized measurement device.

METHODS

Ten cadaveric lower extremity specimens were tested in intact state and after serial sectioning of the syndesmotic structures (anterior inferior tibiofibular ligament [AiTFL], interosseous ligament [IOL], posterior inferior tibiofibular ligament [PiTFL], deltoid). Diagnostic ankle arthroscopy was performed after each sectioning. Manual external rotational stress was applied across the tibiofibular joint. Custom-manufactured spherical balls of increasing diameter mounted on the end of an arthroscopic probe were inserted into the tibiofibular space to determine the degree of diastasis of the tibiofibular joint under each condition.

RESULTS

A ball 3 mm in diameter reliably indicated a high likelihood of combined disruption of the AiTFL and IOL. Disruption of the AiTFL alone could not be reliably distinguished from the intact state.

CONCLUSION

Use of a spherical probe placed into the tibiofibular space during manual external rotation of the ankle provided an objective measure of syndesmotic instability. Passage of a 2.5-mm probe indicated some disruption of the syndesmosis, but the test had poor negative predictive value. Passage of a 3.0-mm spherical probe indicated very high likelihood of disruption of both the AiTFL and the IOL.

CLINICAL RELEVANCE

The findings challenge the previously used but unsupported standard of a 2-mm diastasis of the tibiofibular articulation for diagnosis of subtle syndesmotic instability.

Isolated Syndesmosis Diastasis: Computed Tomography Scan Assessment With Arthroscopic Correlation

PURPOSE

To investigate which method can predict tibiofibular diastasis more accurately among the tibiofibular interval at the ankle joint level or previous parameters taken 1 cm above the joint line.

METHODS

An arthroscopic examination was performed in 78 consecutive patients with anterolateral ankle pain. Four different methods were performed to take measurements of the tibiofibular interval using an axial computed tomography (CT) scan under existing arthroscopic diagnosis. Three previously reported parameters were assessed at 1 cm above the joint level. In the first method, 2 measurements were obtained. The anterior measurement was the closest distance between the anterior border of the fibula and anterior tibial tubercle. The posterior measurement was the closest distance between the medial border of the fibula and posterior tibial tubercle. In the second method, an angle between the fibular axis and the line connecting the anterior and posterior tibial tubercle was measured. In the third method, the nearest distance between the line perpendicular to the line connecting the tubercles at the anterior tubercle of the distal tibia and the anterior-most margin of the fibula was measured. The fourth method, which was developed in this study, measured the narrowest tibiofibular distance at the joint level. Data were analyzed using Student's t-test and the receiver operating characteristic curve to make comparisons among 4 CT-based parameters.

RESULTS

In the comparison between the patients with arthroscopic diastasis and without diastasis, the posterior parameter in the first method and the narrowest tibiofibular distance at the joint level in the fourth method showed a significant difference (P < .05) The areas under the receiver operating characteristic curve (AUCs) of the anterior and posterior parameter of the first method were 0.58 (95% confidence interval [CI], 0.43-0.73; P = .167) of anterior measurement and 0.6 (95% CI, 0.45-0.75; P = .029) of posterior measurement, respectively. The second and third methods presented AUCs of 0.59 (95% CI, 0.44-0.74; P = .458) and 0.48 (95% CI, 0.33-0.64; P = .987), respectively. The fourth method presented an AUC of 0.86 (95% CI, 0.75-0.94; P = .000). When the syndesmosis was measured at the joint level, 2 mm of syndesmosis interval as a cutoff value showed 76% of sensitivity and 81% of specificity.

CONCLUSIONS

Syndesmosis assessment using an axial CT scan at the joint level best correlated with the arthroscopic examination. When there is more than 2 mm of widening in syndesmosis on the axial CT scan at the joint level, there is a high likelihood of diastasis of the distal tibiofibular syndesmosis in patients who are suspicious clinically to have acute or chronic syndesmosis lesion.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

The Broken "Ring of Fire": A New Radiological Sign as Predictor of Syndesmosis Injury?

Background:

Subcircumferential periosteal edema above the ankle joint is frequently present on magnetic resonance imaging (MRI) with syndesmosis injuries but has not been previously reported. Fluid height within the interosseous membrane also has not previously been shown to be associated with syndesmosis injury severity.

Purpose:

To investigate whether a new sign on MRI and measurement of the length of fluid within the interosseous membrane above the ankle may be used to enable identification of a syndesmosis injury and allow differentiation from lateral ligament injury.

Study Design:

Cohort study (diagnosis); Level of evidence, 3.

Methods:

Three groups of patients (those with an isolated syndesmosis injury [SI group], isolated lateral ligament injury [LLI group], and no injury [NI group]) who had an ankle MRI for another reason were identified from a patient notes database and the MRI scans retrieved. The scans were anonymized and independently assessed by 8 clinicians (surgeons and radiologists) who were blinded to the diagnosis. The maximum length of fluid above the ankle within the intraosseous membrane was measured for each patient. The presence or absence of distal anterior, lateral, and posterior tibial periosteal edema was recorded (broken “ring of fire”).

Results:

Measurement of the length of fluid above the ankle had excellent intraobserver reliability (intraclass correlation coefficient, 0.97; 95% CI, 0.93-0.99) but poor interobserver reliability. Fluid extended higher in both the LLI group (P = .0043) and SI group (P = .0058) than the NI group, but there was no significant difference between the LLI and SI groups (P = .3735), indicating that this measurement cannot differentiate between the injuries. The presence of the broken “ring of fire” around the distal tibia was significantly more frequent in the SI group when compared with both LLI and NI groups (P < .00001). The sensitivity of this sign is 49%, but when present, this sign has a 98% specificity for syndesmosis injury.

Conclusion:

The presence of tibial subcircumferential periosteal edema 4 to 6 cm above the ankle joint (the “ring of fire”) is highly suggestive of a syndesmosis injury. This new radiological sign can assist with early identification of such injuries. The measurement of height of fluid above the ankle within the interosseous membrane is variable and cannot differentiate severe ankle sprains from high ankle sprains involving the syndesmosis.

Arthroscopic Quantification of Syndesmotic Instability in a Cadaveric Model

PURPOSE

To investigate whether arthroscopy or stress radiography can identify instability resulting from single-ligament injury of the ankle syndesmosis and to determine whether either modality is capable of differentiating between various levels of ligament injury.

METHODS

Syndesmotic/deltoid ligament sectioning was performed in 10 cadaver legs. Arthroscopic evaluation and fluoroscopic stress testing were completed after each sectioning. In group 1 (n = 5), sectioning began with anteroinferior tibiofibular ligament (AITFL), then interosseous membrane (IOM), posteroinferior tibiofibular ligament (PITFL), and deltoid. In group 2 (n = 5), this order was reversed. Measurements were made by determining the largest-sized probe that would fit in the anterior and posterior syndesmosis. Radiographic parameters included tibiofibular overlap/clear space and medial clear space.

RESULTS

No radiographic measurement proved useful in distinguishing between intact and transected AITFL. Anterior probe (AP) size reached significance when distinguishing between intact and AITFL-transected specimens (P < .0001). AP detected significant differences comparing single with 2-, 3-, and 4-ligament (AITFL, IOM, PITFL, deltoid) disruptions (P = .05, <.0001, and <.0001, respectively). Significant differences were observed between 2- and 3/4-ligament (P = .02) transections. Posterior probe (PP) size detected significant differences between intact and single-, double-, triple-, and complete ligament transections (P values .0006, <.0001, <.0001, <.001, respectively). PP detected significant differences between single- and double-, triple-, and complete ligament transection models (P = .0075, .0010, and .0010, respectively). PP distinguished between 2- and 3/4-ligament (P = .03) transections.

CONCLUSIONS

Stress radiography did not distinguish between intact and single-ligament disruption, and was unreliable in distinguishing between sequential transection models. Arthroscopy significantly predicted isolated disruption of the AITFL or deltoid ligaments. Also, probing was able to differentiate between most patterns of ligament injury, including sequential transections.

CLINICAL RELEVANCE

These data can aid surgeons during arthroscopy of the ankle when attempting to correlate intraoperative syndesmotic evaluation findings with the extent of ligament injury.

Preoperative radiography versus computed tomography for surgical planning for ankle fractures

PURPOSE

To review preoperative radiography and computed tomography (CT) of the ankle in 69 patients who underwent surgery for ankle fractures to determine the value of CT in diagnosis and surgical planning.

METHODS

Preoperative radiography and CT of the ankle of 46 women and 23 men aged 17 to 90 (mean, 48.8) years were reviewed. CT was deemed necessary when radiographs showed the following features: (1) comminuted fracture of the medial malleolus involving the tibial plafond, (2) comminuted fracture of the posterior malleolus, (3) presence of loose bodies, and/or (4) suspected Chaput or Volkman fracture fragment. Two orthopaedic surgeons independently reviewed the radiographs to look for any of the above features for which CT was indicated. In patients whose radiographs did not show any of the above features, each surgeon formulated a surgical plan based on radiographs alone and decided if any modification was needed after reviewing the CT scan.

RESULTS

Based on radiographs of the 69 patients, 19 (28%) patients had features of posterior malleolar comminution (n=7), medial malleolar comminution (n=7), suspected Chaput fracture fragment (n=1), suspected Volkman fracture fragment (n=1), and combination of 2 lesions (n=3), and were deemed to require CT. In 10 (20%) of the remaining 50 patients, the surgical plan was modified after review of the CT scan. The intra- and inter-observer agreement was good to excellent.

CONCLUSION

Radiography alone is not adequate for surgical planning for ankle fractures. More accurate imaging tools such as CT are needed to enable a more accurate diagnosis and surgical planning.

Incisura Morphology as a Risk Factor for Syndesmotic Malreduction

BACKGROUND

The goal of this study was to objectively assess if rotational or translational syndesmotic malreduction is associated with certain syndesmotic morphologies. Prior studies based on subjective assessment of syndesmotic morphology and reduction have not shown any difference between groups.

METHODS

Thirty-five prospectively recruited patients with operatively treated syndesmotic injuries were recruited at an Urban Level I Trauma Center. Patients underwent postoperative bilateral computed tomographic (CT) scans of the ankle to assess incisura depth and syndesmotic reduction. The uninjured extremity was used as a control. Side-to-side differences of syndesmotic reduction were measured at several anatomic points and compared to the incisura depth.

RESULTS

There was a significant correlation between more shallow syndesmoses and increased anterior translation of the fibula in the incisura (r = -0.63, P ≤ .001). Six of 8 patients with "shallow" (≤2.5 mm) incisura were anteriorly malreduced greater than or equal to 1.5 mm compared to the contralateral ankle. The anterior malreduction rate in those with a shallow incisura was significantly greater than in the "non-shallow" patients (P < .001). There were 9 patients with incisurae greater than or equal to 4.5 mm deep. Five of the "deep" patients had posterior malreductions greater than or equal to 1.5 mm. The posterior malreduction rate in the "deep" group was significantly greater than the "non-deep" patients (P = .02). There was a significant correlation between increasing syndesmotic depth and increased malrotation (r = .46, P = .01).

CONCLUSION

Syndesmotic morphology was found to be associated with specific malreduction patterns. Shallow syndesmoses were correlated with anterior fibular malreduction, and were less likely to be malrotated. Conversely, deep syndesmoses predisposed to posterior sagittal plane and rotational malalignment. Preoperative CT scans that assess the syndesmosis morphology may allow surgeons to alter reduction strategies to avoid syndesmotic malreduction.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Magnetic resonance imaging characterization of individual ankle syndesmosis structures in asymptomatic and surgically treated cohorts

PURPOSE

Historically, syndesmosis injuries have been underdiagnosed. The purpose of this study was to characterize the 3.0-T MRI presentations of the distal tibiofibular syndesmosis and its individual structures in both asymptomatic and injured cohorts.

METHODS

Ten age-matched asymptomatic volunteers were imaged to characterize the asymptomatic syndesmotic anatomy. A series of 21 consecutive patients with a pre-operative 3.0-T ankle MRI and subsequent arthroscopic evaluation for suspected syndesmotic injury were reviewed and analysed. Prospectively collected pre-operative MRI findings were correlated with arthroscopy to assess diagnostic accuracy [sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV)].

RESULTS

Pathology diagnosed on pre-operative MRI correlated strongly with arthroscopic findings. Syndesmotic ligament disruption was prospectively diagnosed on MRI with excellent sensitivity, specificity, PPV, NPV, and accuracy: anterior inferior tibiofibular ligament (87.5, 100, 100, 71.4, 90.5 %); posterior inferior tibiofibular ligament (N/A, 95.2, 0.0, 100, 95.2 %); and interosseous tibiofibular ligament (66.7, 86.7, 66.7, 86.7, 81.0 %).

CONCLUSIONS

Pre-operative 3.0-T MRI demonstrated excellent accuracy in the diagnosis of syndesmotic ligament tears and allowed for the visualization of relevant individual syndesmosis structures. Using a standard clinical ankle MRI protocol at 3.0-T, associated ligament injuries could be readily identified. Clinical implementation of optimal high-field MRI sequences in a standard clinical ankle MRI exam can aid in the diagnosis of syndesmotic injuries, augment pre-operative planning, and facilitate anatomic repair by providing additional details regarding the integrity of individual syndesmotic structures not discernible through physical examination and radiographic assessments.

LEVEL OF EVIDENCE

II.

Isolated syndesmotic injuries in acute ankle sprains: diagnostic significance of clinical examination and MRI

PURPOSE

Acute ankle sprains are frequently accompanied by syndesmotic injuries. These injuries are often overlooked in clinical examinations. The aim of this study was (1) to evaluate the incidence of syndesmotic injuries in acute ankle sprains using MRI, (2) to determine the accuracy of common clinical diagnostic tests, (3) to analyse their inter-rater reliability, and (4) to evaluate the role of clinical symptoms in the diagnosis of syndesmotic injuries.

METHODS

A total of 100 patients with acute ankle sprain injury without associated fractures in plane radiographs were enrolled. The clinical assessment was performed by two independent examiners. Local findings, ankle ligament palpation, squeeze test, external rotation test, Drawer test, Cotton test, and the crossed-leg test (two examiners) were compared with MRI results (read by two blinded radiologists) as a reference standard.

RESULTS

Ninety-six participants (57% male) met the inclusion criteria. MRI detected a ruptured anterior inferior tibiofibular ligament (AITFL) in 14 patients (15%); 9 partial tears and 5 complete tears were evident. Evidence of pain at rest was found to predict syndesmotic injuries most accurately (p = 0.039). The palpation test over the proximal fibula produced the highest inter-rater correlation (κ = 0.65), but the lowest sensitivity for syndesmotic injuries of 8%. All other clinical tests demonstrated moderate to fair inter-rater reliabilities (κ = 0.37-0.52). Low sensitivity values were found with all clinical tests (13.9-55.6%).

CONCLUSION

In this study, clinical examination was insufficient to detect syndesmotic injuries in acute ankle sprains. MRI scanning revealed a syndesmotic lesion in 15% of patients. MRI scanning should be recommended in patients with ongoing pain at rest following ankle sprains.

LEVEL OF EVIDENCE

I.

Classification and diagnosis of acute isolated syndesmotic injuries: ESSKA-AFAS consensus and guidelines

PURPOSE

The aim of the present study was to perform a systematic review of the current classification systems, and the clinical and radiological tests for the acute isolated syndesmotic injuries to identify the best method of classification and diagnosis allowing the surgeon to choose the appropriate management.

METHODS

A systematic review of the literature according to the PRISMA guidelines has been performed. A comprehensive search using various combinations of the keywords "classification", "grading system", "ankle injury", "ligament", "syndesmotic injury", "internal fixation", "acute", "synostosis", "ligamentoplasties", "clinical", "radiological" over the years 1962-2015 was performed. The following databases were searched: MEDLINE, Google Scholar, EMBASE and Ovid.

RESULTS

The literature search resulted in 345 references for classification systems and 308 references for diagnosis methods, of which 283 and 295 were rejected due to off-topic abstract and/or failure to fulfil the inclusion criteria. After reading the remaining full-text articles, we included 27 articles describing classification systems and 13 articles describing diagnostic tests for acute isolated syndesmotic injuries.

CONCLUSIONS

The ESSKA-AFAS consensus panel recommends distinguishing acute isolated syndesmotic injury as stable or unstable. Stable injuries should be treated non-operatively with a short-leg cast or brace, while unstable injuries should be managed operatively. The recommended clinical tests include: tenderness on palpation over the anterior tibiofibular ligament, the fibular translation test and the Cotton test. Radiographic imaging must include an AP view and a mortise view of the syndesmosis to check the tibiofibular clear space, medial clear space overlap, tibial width and fibular width.

LEVEL OF EVIDENCE

IV.

Stable Versus Unstable Grade II High Ankle Sprains: A Prospective Study Predicting the Need for Surgical Stabilization and Time to Return to Sports

PURPOSE

To investigate grade II syndesmosis injuries in athletes and identify factors important in differentiating stable from dynamically unstable ankle sprains and those associated with a longer time to return to sports.

METHODS

Sixty-four athletes with an isolated syndesmosis injury (without fracture) were prospectively assessed, with a mean follow-up period of 37 months (range, 24 to 66 months). Those with an associated deltoid ligament injury or osteochondral lesion were included. Those whose injuries were considered stable (grade IIa) were treated conservatively with a boot and rehabilitation. Those whose injuries were clinically unstable underwent arthroscopy, and if instability was confirmed (grade IIb), the syndesmosis was stabilized. Clinical and magnetic resonance imaging assessments of injury to individual ligaments were recorded, along with time to return to play. A power analysis estimated that each group would need 28 patients.

RESULTS

All athletes returned to the same level of professional sport. The 28 patients with grade IIa injuries returned at a mean of 45 days (range, 23 to 63 days) compared with 64 days (range, 27 to 104 days) for those with grade IIb injuries (P < .0001). There was a highly significant relationship between clinical and magnetic resonance imaging assessments of ligament injury (anterior tibiofibular ligament [ATFL], anterior-inferior tibiofibular ligament [AITFL], and deltoid ligament, P < .0001). Instability was 9.5 times as likely with a positive squeeze test and 11 times as likely with a deltoid injury. Combined injury to the anterior-inferior tibiofibular ligament and deltoid ligament was associated with a delay in return to sports. Concomitant injury to the ATFL indicated a different mechanism of injury-the syndesmosis is less likely to be unstable and is associated with an earlier return to sports.

CONCLUSIONS

A positive squeeze test and injury to the ATFL and deltoid ligament are important factors in differentiating stable from dynamically unstable grade II injuries and may be used to identify which athletes may benefit from early arthroscopic assessment and stabilization. They may also be important in predicting the time frame for athletes' expected return to play.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

A rare type of ankle fracture: Syndesmotic rupture combined with a high fibular fracture without medial injury

High fibular spiral fractures are usually caused by pronation-external rotation mechanism. The foot is in pronation and the talus externally rotates, causing a rupture of the medial ligaments or a fracture of the medial malleolus. With continued rotation the anterior and posterior tibiofibular ligament will rupture, and finally, the energy leaves the fibula by creating a spiral fracture from anterior superior to posterior inferior. In this article we demonstrate a type of ankle fracture with syndesmotic injury and high fibular spiral fractures without a medial component. This type of ankle fractures cannot be explained by the Lauge-Hansen classification, since it lacks injury on the medial side of the ankle, but it does have the fibular fracture pattern matching the pronation external rotation injury (anterior superior to posterior inferior fracture). We investigated the mechanism of this injury illustrated by 3 cases and postulate a theory explaining the biomechanics behind this type of injury.

Football injuries of the ankle: A review of injury mechanisms, diagnosis and management

Football is the most popular sport worldwide and is associated with a high injury rate, most of which are the result of trauma from player contact. Ankle injuries are among the most commonly diagnosed injuries in the game. The result is reduced physical activity and endurance levels, lost game time, and considerable medical cost. Sports medicine professionals must employ the correct diagnostic tools and effective treatments and rehabilitation protocols to minimize the impact of these injuries on the player. This review examines the diagnosis, treatment, and postoperative rehabilitation for common football injuries of the ankle based on the clinical evidence provided in the current literature.

Correlation Between the Lauge-Hansen Classification and Ligament Injuries in Ankle Fractures

OBJECTIVE

To evaluate the ability of the Lauge-Hansen classification to predict ligament injuries in ankle fractures using magnetic resonance imaging (MRI) and intraoperative findings.

DESIGN

Prospective evaluation in consecutive patients.

SETTING

Academic level 1 trauma center.

PATIENTS

Three-hundred patients with an operatively treated ankle fracture who met the inclusion and exclusion criteria.

INTERVENTION

Injury ankle radiographs were assigned to a Lauge-Hansen classification. MRI scans were obtained to evaluate the syndesmotic and deltoid ligaments. A Lauge-Hansen classification for each patient was recorded based on intraoperative findings.

MAIN OUTCOME MEASUREMENTS

Comparisons were made between the predicted ankle ligamentous injuries based on radiographic Lauge-Hansen classifications, preoperative MRI analyses, and intraoperative findings.

RESULTS

On the basis of the Lauge-Hansen system and injury radiographs, 77% (231/300) were classified as supination external rotation, 13% (40/300) were pronation external rotation, 4% (11/300) were supination adduction, <1% (1/300) was pronation abduction, and 6% (17/300) were not classifiable. Of the 283 fractures that were classified into Lauge-Hansen classes, 266 (94%) had MRI readings of ligamentous injuries consistent with the Lauge-Hansen predictions. Intraoperative findings also highly correlated with the Lauge-Hansen class of ankle fractures, with nearly complete agreement. Comparing MRI and intraoperative findings revealed discrepancies in 6% (16/283) of ankle fracture classifications.

CONCLUSIONS

In our large cohort of patients, comparisons between injury radiographs, preoperative MRI, and intraoperative findings suggest that the Lauge-Hansen system is an accurate predictor of ligamentous injuries. The predictions based on the Lauge-Hansen system can be useful for fracture reduction maneuvers and operative planning.

LEVEL OF EVIDENCE

Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Effectiveness of a single platelet-rich plasma injection to promote recovery in rugby players with ankle syndesmosis injury

AIMS

To determine whether a single ultrasound-guided platelet-rich plasma (PRP) injection into the anterior inferior tibiofibular ligament (AITFL) reduces the time for rugby athletes to return to function and match play following MRI confirmed ankle syndesmosis injury.

METHODS

Cohort controlled pilot study. 10 Rugby Union players were recruited during the 2014 season, and consented to receive a single autologous PRP injection into the AITFL within 14 days of MRI confirmed ankle syndesmosis injury. A historical control group included 11 comparable Rugby Union players between 2011 and 2013 who were treated conservatively with the same inclusion criteria and rehabilitation protocol as the intervention group. Participants followed a standardised rehabilitation protocol involving simple milestones for progression. Early functional tests were performed 2 weeks after the removal of the CAM (controlled ankle motion) boot. Time to return to play was recorded. Repeat functional testing occurred within 1 week of return to play.

RESULTS

Groups were comparable in anthropometrics, playing position and MRI injury severity. Time to return to play was significantly less in the intervention group (p=0.048). Following return to play, athletes in the intervention group showed higher agility (p=0.002) and vertical jump (p=0.001). There was a lower level of fear avoidance associated with rugby in the intervention group (p=0.014).

CONCLUSIONS

This pilot study shows that, following ankle syndesmosis injury, a single autologous PRP injection may accelerate safe and successful return to Rugby Union, with improved functional capacity and reduced fear avoidance. It demonstrates the feasibility of a randomised controlled trial to further assess this therapy.

TRIAL REGISTRATION NUMBER

ANZCTRN12614000055606.

In Vivo Syndesmotic Overcompression After Fixation of Ankle Fractures With a Syndesmotic Injury

OBJECTIVES

The goals of this study were to assess syndesmotic reductions using computerized tomography and to determine whether malreductions are associated with certain injury types or reduction forceps.

DESIGN

Prospective cohort.

SETTING

Urban level 1 trauma center.

PATIENTS

Twenty-seven patients with operatively treated syndesmotic injuries were recruited prospectively.

INTERVENTION

Patients underwent postoperative bilateral computerized tomography of the ankle and hindfoot to assess syndesmotic reduction. The uninjured extremity was used as a control.

MAIN OUTCOME MEASUREMENT

Side-to-side differences of the fibular position within the tibial incisura were measured at several anatomic points and analyzed based on injury type, the presence of posterior malleolar injury, level of fracture, and type of reduction forceps used.

RESULTS

On average, operatively treated syndesmotic injuries were overcompressed (fibular medialization) by 1 mm (P < 0.001) and externally rotated by 5° (P = 0.002) when compared with the uninjured extremity. The absence of a posterior malleolar injury and Weber B (OTA 44-B) fractures seemed to have a protective effect against malrotation, but not against overcompression. There was no difference in malreduction based on the type of the clamp used.

CONCLUSIONS

It is possible, and highly likely based on these data, to overcompress the syndesmosis when using reduction forceps. Care should be taken to avoid overcompression, as this may affect the ankle motion and functional outcomes. To our knowledge, this is the first in vivo series of syndesmotic overcompression.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Technical Considerations in the Treatment of Syndesmotic Injuries Associated With Ankle Fractures

Malleolar ankle fractures associated with syndesmotic injuries are common. Diagnosis of the syndesmotic injury can be difficult and often requires intraoperative fluoroscopic stress testing. Accurate reduction and stable fixation of the syndesmosis are critical to maximize patient outcomes. Recent literature has demonstrated that the unstable syndesmosis is particularly prone to iatrogenic malreduction. Multiple types of malreduction can occur, including translational, rotational, and overcompression. Knowledge of the technical details regarding intraoperative reduction methods and reduction assessment can minimize the risk of syndesmotic malreduction and improve patient outcomes.

Analysis of PITFL injuries in rotationally unstable ankle fractures

BACKGROUND

Reduction and stabilization of the syndesmosis in unstable ankle fractures is important for ankle mortise congruity and restoration of normal tibiotalar contact forces. Of the syndesmotic ligaments, the posterior inferior tibiofibular ligament (PITFL) provides the most strength for maintaining syndesmotic stability, and previous work has demonstrated the significance of restoring PITFL function when it remains attached to a posterior malleolus fracture fragment. However, little is known regarding the nature of a PITFL injury in the absence of a posterior malleolus fracture. The goal of this study was to describe the PITFL injury pattern based on magnetic resonance imaging (MRI) and intraoperative observation.

METHODS

A prospective database of all operatively treated ankle fractures by a single surgeon was used to identify all supination-external rotation (SER) types III and IV ankle fracture patients with complete preoperative orthogonal ankle radiographs and MRI. All patients with a posterior malleolus fracture were excluded. Using a combination of preoperative imaging and intraoperative findings, we analyzed the nature of injuries to the PITFL. In total, 185 SER III and IV operatively treated ankle fractures with complete imaging were initially identified.

RESULTS

Analysis of the preoperative imaging and operative reports revealed 34% (63/185) had a posterior malleolus fracture and were excluded. From the remaining 122 ankle fractures, the PITFL was delaminated from the posterior malleolus in 97% (119/122) of cases. A smaller proportion (3%; 3/122) had an intrasubstance PITFL rupture.

CONCLUSIONS

Accurate and stable syndesmotic reduction is a significant component of restoring the ankle mortise after unstable ankle fractures. In our large cohort of rotationally unstable ankle fractures without posterior malleolus fractures, we found that most PITFL injuries occur as a delamination off the posterior malleolus. This predictable PITFL injury pattern may be used to guide new methods for stabilizing the syndesmosis in these patients.

LEVEL OF EVIDENCE

Level IV, case series.

Prognosis of ankle syndesmosis injury

PURPOSE

Ankle syndesmosis injury has been associated with persistent pain and prolonged recovery; however, no predictors of prolonged recovery have been identified. The aims of this study were to establish prognosis for ankle syndesmosis injury compared with a lateral ankle sprain and to explore factors associated with prolonged recovery.

METHODS

Participants (n = 63) age 21 ± 3.2 yr, with acute ankle ligament injuries (diagnosed through magnetic resonance imaging), were recruited from 10 sport clubs and sports medicine and physiotherapy clinics in two Australian cities. Follow-up was until full recovery and with preinjury activity level. Time to return to play was compared between injury types using Kaplan-Meier survival curves. Secondary analysis investigated putative factors that increased risk of prolonged recovery. For this analysis, participants unrecovered at 2 wk completed the following: Fear Avoidance Beliefs Questionnaire (FABQ); Star Excursion Balance Test, weight-bearing lunge, and vertical jump (VJ). These variables were correlated with time to recovery using bivariate Pearson's r correlation coefficient.

RESULTS

The median recovery time for conservatively treated ankle syndesmosis injury was 62 and 15 d for lateral sprain. The sport-specific subscale scores of the FABQ were significantly higher (P = 0.017) for the ankle syndesmosis group, whereas vertical jump height was lower for this group, (P = 0.052). No baseline variables were strong predictors (r ≥ 0.6) of recovery. Moderate correlations were found for VJ (r = -0.471, P = 0.004) and the sport-specific subscale of the FABQ (r = 0.463, P = 0.004).

CONCLUSIONS

Conservatively treated ankle syndesmosis injuries took four times longer to recover than lateral ankle sprain. Tests such as VJ and FABQ may identify individuals at risk of prolonged recovery and allow health professionals to determine realistic and appropriate time to recovery.

Clinical orthopedic examination findings in the lower extremity: correlation with imaging studies and diagnostic efficacy

The lower-extremity anatomy is complex and normal function is dependent on intact osteochondral, musculotendinous, and ligamentous structures. Injury may result in pain and functional limitation. Specific clinical tests are used to help isolate and define the pathoanatomy; however, their terminology may be confusing to the radiologist and the diagnostic value of these tests may not be well understood. This article presents an algorithmic approach to evaluation of the hip, knee, and ankle to improve the radiologist's understanding of lower-extremity physical examination. Knowledge of test terminology, clinical utility, and diagnostic accuracy will improve clinical and radiologic correlation. The article reviews the common clinical tests used to evaluate the lower extremity and provides an algorithm to establish a clinical examination road map and rapidly review the clinical utility and study hierarchy of a particular test. The sensitivity and specificity of the clinical tests and magnetic resonance (MR) imaging are reviewed because these parameters vary, and an understanding of the diagnostic utility of both the clinical and imaging tests is important in accurately formulating a definitive diagnosis. The structured algorithmic approach to lower-extremity examination described here, knowledge of test jargon, and familiarity with the diagnostic accuracy of the clinical and MR imaging examinations may help the radiologist focus image search patterns and provide detailed and clinically relevant reports. Online supplemental material is available for this article.

Ankle syndesmosis: a qualitative and quantitative anatomic analysis

BACKGROUND

Syndesmosis sprains can contribute to chronic pain and instability, which are often indications for surgical intervention. The literature lacks sufficient objective data detailing the complex anatomy and localized osseous landmarks essential for current surgical techniques.

PURPOSE

To qualitatively and quantitatively analyze the anatomy of the 3 syndesmotic ligaments with respect to surgically identifiable bony landmarks.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Sixteen ankle specimens were dissected to identify the anterior inferior tibiofibular ligament (AITFL), posterior inferior tibiofibular ligament (PITFL), interosseous tibiofibular ligament (ITFL), and bony anatomy. Ligament lengths, footprints, and orientations were measured in reference to bony landmarks by use of an anatomically based coordinate system and a 3-dimensional coordinate measuring device.

RESULTS

The syndesmotic ligaments were identified in all specimens. The pyramidal-shaped ITFL was the broadest, originating from the distal interosseous membrane expansion, extending distally, and terminating 9.3 mm (95% CI, 8.3-10.2 mm) proximal to the central plafond. The tibial cartilage extended 3.6 mm (95% CI, 2.8-4.4 mm) above the plafond, a subset of which articulated directly with the fibular cartilage located 5.2 mm (95% CI, 4.6-5.8 mm) posterior to the anterolateral corner of the tibial plafond. The primary AITFL band(s) originated from the tibia 9.3 mm (95% CI, 8.6-10.0 mm) superior and medial to the anterolateral corner of the tibial plafond and inserted on the fibula 30.5 mm (95% CI, 28.5-32.4 mm) proximal and anterior to the inferior tip of the lateral malleolus. Superficial fibers of the PITFL originated along the distolateral border of the posterolateral tubercle of the tibia 8.0 mm (95% CI, 7.5-8.4 mm) proximal and medial to the posterolateral corner of the plafond and inserted along the medial border of the peroneal groove 26.3 mm (95% CI, 24.5-28.1 mm) superior and posterior to the inferior tip of the lateral malleolus.

CONCLUSION

The qualitative and quantitative anatomy of the syndesmotic ligaments was reproducibly described and defined with respect to surgically identifiable bony prominences.

CLINICAL RELEVANCE

Data regarding anatomic attachment sites and distances to bony prominences can optimize current surgical fixation techniques, improve anatomic restoration, and reduce the risk of iatrogenic injury from malreduction or misplaced implants. Quantitative data also provide the consistency required for the development of anatomic reconstructions.

Evaluation and management of injuries of the tibiofibular syndesmosis

INTRODUCTION

Injury to the tibiofibular syndesmosis often arises from external rotation force acting on the foot leading to eversion of the talus within the ankle mortise and increased dorsiflexion or plantar flexion. Such injuries can present in the absence of a fracture. Therefore, diagnosis of these injuries can be challenging, and often stress radiographs are helpful. Magnetic resonance imaging scans can be a useful adjunct in doubtful cases. The management of syndesmotic injuries remains controversial, and there is no consensus on how to optimally fix syndesmosis. This article reviews the mechanism of injury, clinical features and investigations performed for syndesmotic injuries and brings the reader up-to-date with the current evidence in terms of the controversies surrounding the management of these injuries.

SOURCES OF DATA

Embase, Pubmed Medline, Cochrane Library, Elsevier and Google Scholar (January 1950-2014).

AREAS OF CONTROVERSY

The management of syndesmotic injuries remains controversial, and there is no consensus on: (i) which ankle fractures require syndesmotic fixation, (ii) the number or the size and the type of screws that should be used for fixation, (iii) how many cortices to engage for fixation, (iv) the level of screw placement above the ankle plafond, (v) the duration for which the screw needs to remain in situ to allow the tibiofibular syndesmosis to heal and (vi) when should patients weight bear.

AREAS OF AGREEMENT

(i) A high proportion of syndesmotic fixations demonstrates malreduction of the syndesmosis, (ii) no need to remove screws routinely, (iii) two screws appear to better one alone and (iv) if syndesmosis injury is not detected or not treated long term, it leads to pain and arthritis.

GROWING POINTS

(i) How to assess the adequacy of syndesmotic reduction using imaging in the peri-operative period, (ii) the use of bio-absorbable materials and Tightrope and (iii) evidence is emerging not to remove syndesmotic screws unless symptomatic.

AREAS OF TIMELY FOR DEVELOPMENT RESEARCH

(i) A bio-absorbable material that can be used to fix the syndesmosis and allow early weight bearing, and (ii) there is a need for developing a surgical technique for adequately reducing the syndesmosis without the exposure to radiation.

Preoperative Radiographic and CT Findings Predicting Syndesmotic Injuries in Supination-External Rotation-Type Ankle Fractures

BACKGROUND

The Lauge-Hansen classification system does not provide sufficient data related to syndesmotic injuries in supination-external rotation (SER)-type ankle fractures. The aim of the present study was to investigate factors helpful for the preoperative detection of syndesmotic injuries in SER-type ankle fractures using radiographs and computed tomography (CT).

METHODS

A cohort of 191 consecutive patients (104 male and eighty-seven female patients with a mean age [and standard deviation] of 50.7 ± 16.4 years) with SER-type ankle fractures who had undergone operative treatment were included. Preoperative ankle radiographs and CT imaging scans were made for all patients, and clinical data, including age, sex, and mechanism of injury (high or low-energy trauma), were collected. Patients were divided into two groups: the stable syndesmotic group and the unstable syndesmotic group, with a positive intraoperative lateral stress test leading to syndesmotic screw fixation. Fracture height, fracture length, medial joint space, extent of fracture, and bone attenuation were measured on radiographs and CT images and were compared between the groups. Binary logistic regression analysis was performed to identify the factors that significantly contributed to unstable syndesmotic injuries. Receiver operating characteristic curves were calculated, and cutoff values were suggested to predict unstable syndesmotic injuries on preoperative imaging measurements.

RESULTS

Of the 191 patents with a SER-type ankle fracture, thirty-eight (19.9%) had a concurrent unstable syndesmotic injury. Age, sex, mechanism of injury, fracture height, medial joint space, and bone attenuation were significantly different between the two groups. In the binary logistic analysis, fracture height, medial joint space, and bone attenuation were found to be significant factors contributing to unstable syndesmotic injuries. The cutoff values for predicting unstable syndesmotic injuries were a fracture height of >3 mm and a medial joint space of >4.9 mm on CT scans, and a fracture height of >7 mm and medial joint space of >4.5 mm on radiographs.

CONCLUSIONS

Fracture height, medial joint space, and bone attenuation were useful factors for the preoperative detection of unstable syndesmotic injuries in SER-type ankle fractures.

LEVEL OF EVIDENCE

Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Ligamentous Injuries and the Risk of Associated Tissue Damage in Acute Ankle Sprains in Athletes: A Cross-sectional MRI Study

BACKGROUND

Ankle joint injuries are extremely common sports injuries, with the anterior talofibular ligament involved in the majority of ankle sprains. There have been only a few large magnetic resonance imaging (MRI) studies on associated structural injuries after ankle sprains.

PURPOSE

To describe the injury pattern in athletes who were referred to MRI for the assessment of an acute ankle sprain and to assess the risk of associated traumatic tissue damage including lateral and syndesmotic ligament involvement.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A total of 261 ankle MRI scans of athletes with acute ankle sprains were evaluated for: lateral and syndesmotic ligament injury; concomitant injuries to the deltoid and spring ligaments and sinus tarsi; peroneal, flexor, and extensor retinacula and tendons; traumatic and nontraumatic osteochondral and osseous changes; and joint effusion. Patients were on average 22.5 years old, and the average time from injury to MRI was 5.7 days. Six exclusive injury patterns were defined based on lateral and syndesmotic ligament involvement. The risk for associated injuries was assessed by logistic regression using ankles with no or only low-grade lateral ligament injuries and no syndesmotic ligament damage as the reference.

RESULTS

With regard to the injury pattern, there were 103 ankles (39.5%) with complete anterior talofibular ligament disruption and no syndesmotic injury, and 53 ankles (20.3%) had a syndesmotic injury with or without lateral ligament damage. Acute osteochondral lesions of the lateral talar dome were seen in 20 ankles (7.7%). The percentage of chronic lateral osteochondral lesions was 1.1%. The risk for talar bone contusions increased more than 3-fold for ankles with complete lateral ligament ruptures (adjusted odds ratio [aOR], 3.43; 95% CI, 1.72-6.85) but not for ankles with syndesmotic involvement. The risk for associated deltoid ligament injuries increased for ankles with complete lateral ligament injuries (aOR, 4.04; 95% CI, 1.99-8.22) compared with patients with no or only low-grade lateral ligament injuries.

CONCLUSION

About 20% of athletes referred for MRI after suffering an acute ankle sprain had evidence of a syndesmotic injury regardless of lateral ligament involvement, while more than half had evidence of any lateral ligament injury without syndesmotic involvement. Concomitant talar osseous and deltoid ligament injuries are common.

Comparison of radiographic stress tests for syndesmotic instability of supination-external rotation ankle fractures: a cadaveric study

OBJECTIVE

According to the classification of Lauge-Hansen, supination-external rotation IV (OTA 44-B) injuries should not have syndesmotic instability; yet, several studies have suggested disruption is present in up to 40% of these injuries based on stress tests. In this study, we examine various stress radiographic parameters in a cadaver model of supination-external rotation IV equivalent injury. We hypothesize that external rotation stress testing and widening of the medial clear space do not always represent syndesmotic instability. Rather, the better predictor of syndesmotic instability will be an increased tibia-fibula clear space with the lateral stress test.

METHODS

Eleven fresh frozen human lower limbs were each secured into a custom frame. External rotation stress test was performed by applying an external moment of 7.5 Nm, and lateral stress test was performed by applying 100 N lateral pull at the distal fibula. True mortise radiographs were taken of intact ankles and while performing external rotation and lateral stress tests at each stage of sequentially sectioning the ankle ligaments. The deltoid ligament was sectioned first, then anterior-inferior tibiofibular ligament, posterior-inferior tibiofibular ligament, and interosseous membrane. Tibiofibular clear space and medial clear space were measured on each radiograph.

RESULTS

External rotation stress test produced significant medial clear space widening when the deltoid ligaments were sectioned (P < 0.05). Lateral stress test produced no significant widening of the tibiofibular clear space until interosseous membranes were sectioned (P < 0.05).

CONCLUSIONS

Lateral stress test with widening of the tibiofibular clear space is the preferred indicator of syndesmotic instability. The external rotation stress is a poor indicator of syndesmotic injury in the setting of deltoid ligament injury.

Injuries to the ankle syndesmosis

➤ Despite being common, syndesmotic injuries are challenging to diagnose and treat.➤ Anatomic reduction of the ankle syndesmosis is critical for good clinical outcomes.➤ Intraoperative three-dimensional radiography and direct syndesmotic visualization can improve rates of anatomic reduction.➤ The so-called gold-standard syndesmotic screw fixation is being brought increasingly into question as new fixation techniques emerge.➤ Syndesmotic screw removal remains controversial, but may allow spontaneous correction of malreductions.

Isolated posterior high ankle sprain: a report of three cases

High ankle sprains are difficult to diagnose and account for 10% of all ankle sprains. A high index of suspicion is essential for diagnosis. High ankle sprains are managed symptomatically, with prolonged rehabilitation. The posterior inferior tibiofibular ligament is the strongest syndesmotic ligament; isolated injury of it is rare. We present 3 cases of isolated posterior high ankle sprain and discuss the relevant anatomy, mechanism of injury, and management.

Syndesmosis injuries

Traumatic injuries to the distal tibiofibular syndesmosis commonly result from high-energy ankle injuries. They can occur as isolated ligamentous injuries and can be associated with ankle fractures. Syndesmotic injuries can create a diagnostic and therapeutic challenge for musculoskeletal physicians. Recent literature has added considerably to the body of knowledge pertaining to injury mechanics and treatment outcomes, but there remain a number of controversies regarding diagnostic tests, implants, techniques, and postoperative protocols. Use of the novel suture button device has increased in recent years and shows some promise in clinical and cadaveric studies. This article contains a review of syndesmosis injuries, including anatomy and biomechanics, diagnosis, classification, and treatment options.

Magnetic resonance imaging as a predictor of return to play following syndesmosis (high) ankle sprains in professional football players

BACKGROUND

Syndesmosis ankle sprains cause greater disability and longer duration of recovery than lateral ankle sprains.

OBJECTIVE

To describe the severity of syndesmosis sprains using several accepted magnetic resonance imaging (MRI) criteria and to assess the interrater reliability of diagnosing syndesmosis injury using these same criteria in professional American football players.

HYPOTHESIS

There is a high degree of interrater reliability of MRI findings in American football players with syndesmosis ankle sprains. These radiographic findings will correlate with time lost to injury, indicating severity of the sprain.

STUDY DESIGN

Uncontrolled retrospective review.

METHODS

Player demographics and time lost to play were recorded among professional football players who had sustained a syndesmosis ankle sprain and underwent standardized ankle MRI. Each image was independently read by 3 blinded musculoskeletal radiologists.

RESULTS

Seventeen players met study criteria. There was almost perfect agreement among the radiologists for diagnosing injury to the syndesmotic membrane; substantial agreement for diagnosing injury to the posterior inferior tibiofibular ligament (PITFL) and in determining the proximal extent of syndesmotic edema/injury; but only fair agreement for diagnosing injury to the anterior inferior tibiofibular ligament and in determining the width of syndesmotic separation. There was a significant correlation between the width of syndesmotic separation and time lost, but no significant correlation between individual syndesmotic ligament injury or proximal extent of syndesmotic edema/injury and time lost.

CONCLUSION

While ankle MRI can identify syndesmotic disruption with a high degree of interobserver agreement, no association was demonstrated between the extent of injury on MRI and the time to return to play following a high ankle sprain.

CLINICAL RELEVANCE

In athletes with suspected high ankle sprains, MRI may help confirm diagnosis or suggest alternative diagnoses when the syndesmotic supporting structures are intact. However, the severity of ligamentous and syndesmotic disruption on MRI cannot help predict recovery times.