A radiographic evaluation of the tibiofibular syndesmosis

Quality of fracture reduction assessed by radiological parameters and its influence on functional results in patients with pilon fractures-A prospective multicentre study

INTRODUCTION

The management of pilon fractures remains a challenging issue. Due to the complexity of factors that influence the outcome, it has been questioned if anatomical reductions of articular fracture are relevant. The lack of a commonly accepted assessment of quality of fracture reduction compounded the uncertainty of the importance of anatomical reduction in pilon fracture. The current study aimed to define parameters that can better assess the reduction quality and to investigate the influence of reduction quality on functional outcomes.

METHODS

Patients with unilateral pilon fracture of the AO/OTA type 43-B or 43-C were consecutively recruited to the study and followed up for 2 years after surgery. Postoperative radiographs of the injured and the contralateral joints were evaluated and 13 radiological parameters measured by 2 independent surgeons. The reliability of the measurements for each parameter was assessed by the Intraclass Correlation Coefficient (ICC), and 4 parameters with the highest ICC scores were deemed most reliable and were selected for further analyses. Functional outcome was assessed by the Foot and Ankle Ability Measure (FAAM) for daily living and sports activities. The 4 most reliable radiologic parameters, together with 3 possible baseline confounders (age, AO/OTA fracture type, and open versus closed injury), were analysed using both univariable and multivariable analysis for their association with the FAAM scores. Secondary outcome measures including pain, ankle range of motion (ROM), quality of life (QoL), and adverse events were also reported.

RESULTS

The length of lateral malleolus (LLM), anterior distal tibia angle, anterior talar shift, and length of medial malleolus scored highest on reliability in ICC assessment (ICC=0.76, 0.72, 0.58, and 0.45, respectively). Only LLM exhibited statistical significant association with the 2-year FAAM results. At the 2-year follow-up, the injured joints on average achieved a ROM of 70.7% (95% CI=63.9-77.6) when compared to the contralateral joints, and patients did not regain the pre-injury QoL overall.

CONCLUSION

The multivariable analysis showed that LLM (independent of age, AO/OTA fracture type, and open/closed injury) was a reliable indicator of reduction quality and a prognostic factor for patient outcome in pilon fracture surgery.

A New Intraoperative Syndesmosis Instability Classification System: Utility and Medium-term Results in Closed Displaced Ankle Fractures

OBJECTIVE

To investigate the utility and medium-term results of a new intra-operative classification system for distal tibiofibular syndesmosis injury in ankle fractures.

METHODS

Between January 2010 and January 2015, 116 patients diagnosed with displaced closed Weber B and C ankle fractures were treated in our department. The etiology of injury was 56 cases of fall-sprain, 36 of traffic injury, 14 of fall from a height, and 10 of multiple injuries. After fixation of the fibular fracture, we classify syndesmosis stability as either normal or one of three grades of instability using the fibular hook traction test. This determined further fixation selection and final syndesmosis treatment.

RESULTS

Of 116 cases, 82 (71%) demonstrated a tibiofibular syndesmosis injury and 52 (45%) were unstable. Twenty-six cases were type I injuries (<4 mm displacement), 41% cases were type II injuries (4-7 mm displacement), and 3% of cases were type III injuries (>7 mm displacement). Types II and III are defined as unstable and require stabilization. Type III injuries have multiplanar instability and require two screws at the syndesmosis. Weber C fractures demonstrate significantly greater degrees of instability than Weber B fractures (χ² = 15.50, P = 0.0014). All patients were followed up for 12-24 months, with no cases of non-union or broken screws. Good and excellent results were achieved in 93% of cases (according to the American Orthopaedic Foot and Ankle Society scoring system).

CONCLUSION

The syndesmosis instability classification system provides a rational and efficient basis for managing syndesmosis instability. Our results from application of the algorithm justify its further evaluation in the treatment of patients with closed displaced Weber B and C ankle fractures.

Dynamic ultrasound evaluation of the syndesmosis ligamentous complex and clear space in acute ankle injury, compared to magnetic resonance imaging and surgical findings

Background: Syndesmosis injuries are often more serious than an injury to the lateral ligament complex of the ankle, with double the recovery time, chronic discomfort and joint instability. Although magnetic resonance imaging (MRI) is considered as the best imaging modality to assess the integrity of the syndesmotic ligamentous complex and clear space, a dynamic ultrasound evaluation may provide an alternative imaging option worthy of exploring.Aim: The aim of this article is to compare the sensitivity and specificity of musculoskeletal ultrasound and MRI, in the diagnosis of syndesmosis pathology, with surgical findings as the reference point.Method: MRI was performed on 114 participants presenting with pain over the lateral aspect of the ankle after injury. This was followed by a dynamic ultrasound examination during which the anterior tibiofibular ligament (ATiFL) was assessed for continuity, contour and haematoma. The tibiofibular clear space was measured with the ankle in a neutral position, followed by internal and external rotation.Results: The Fisher’s exact test was used to determine non-random associations between variables and compute statistical significance (p < 0.05). Ultrasound achieved a sensitivity of 86.3%, specificity of 97% with a false-positive rate of 3%. The sensitivity of MRI is similar to that of ultrasound (86%) with a specificity of 100%.Conclusion: Although both imaging tests performed very well, MRI was slightly better at excluding pathology while both tests performed equally in demonstrating pathology. As a simple, inexpensive and reproducible test, dynamic ultrasound can thus be considered as an alternative to MRI in acute ankle pathology.

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.

Unstable fragility fractures of the ankle in the elderly: Transarticular Steinmann pin or external fixation

INTRODUCTION

Because of poor skin conditions and comorbidity, open reduction and internal fixation in ankle fractures is frequently contra-indicated in the elderly. This study reports the results of two temporary fixation types in fragility fractures in the older patient: transarticular Steinmann pin fixation and external fixation.

METHODS

Patients aged over 60 treated with a Steinmann pin or external fixation were retrospectively included. Patient, fracture and treatment characteristics were collected.

RESULTS

Fifteen patients were included. Nine were managed using a Steinmann pin and six by external fixation. All reached fracture consolidation. Patients treated with a Steinmann pin underwent a median of 2 operations and the pin was left in situ for 80 days. Three patients suffered from superficial wound infection. X-ray showed malreduction in 67% and only two patients returned to pre-injury mobility. A median of 2 operations with 32 fixation days was reported in the external fixation group. This group showed one deep infection. In 50% there was malreduction, one patient experienced disability in ambulation at the end of treatment.

CONCLUSION

Both techniques show few complications, but have, as expected, poor results in fracture reduction and functional outcome. External fixation and subsequent internal fixation could result in better functional outcome.

Radiological assessment of ankle syndesmotic reduction

INTRODUCTION

The intraoperative assessment of adequacy of syndesmotic reduction is challenging. The aim of this study was to develop a radiographic measure based on the lateral ankle view to assess both the normal and abnormal relationship between the tibia and fibula after simulated syndesmotic malreduction and to evaluate the effect on commonly used mortise measurements.

METHODS

Mortise and talar dome lateral radiographs were obtained in eight fresh-frozen cadaveric specimens before and following syndesmosis division and posterior fibular displacement of 2mm increments. Using the technique described, on the lateral radiograph the anterior fibular line ratio (AFL ratio) and posterior fibular line distance (PFL distance) were measured. Both measures were based on the anterior and posterior distal tibia articular margins and flat borders of the fibula.

RESULTS

Inter- and intraobserver reliability of the AFL ratio and PFL distance measured almost perfect agreement. In all uninjured specimens the AFL lay just anterior to the midpoint of the tibia and the PFL intersected the posterior tibia articular margin or lay just anterior to it, not posterior. At 2, 4 and 6mm of posterior fibular displacement the decrease in AFL ratio and PFL distance showed significant differences between all pairwise comparisons.

CONCLUSION

The proposed new measures of syndesmotic reduction are reproducible and capable of detecting from 2mm of sagittal fibula displacement and can be useful adjuncts in the assessment of syndesmotic reduction.

Distal Tibiofibular Syndesmosis: Anatomy, Biomechanics, Injury and Management

A stable and precise articulation of the distal tibiofibular syndesmosis is essential for normal motion of the ankle joint. Injury to the syndesmosis occurs through rupture or bony avulsion of the syndesmotic ligament complex. External rotation of the talus has been identified as the major mechanism of syndesmotic injury. None of the syndesmotic stress tests was sensitive or specific; therefore the diagnosis of syndesmotic injury should not be made based on the medical history and physical examination alone. With the improvement in ankle arthroscopic technique, it can be used as a diagnostic and therapeutic tool in the management of distal tibiofibular syndesmosis injury.

Is Incisura Fibularis a Reliable Landmark for Assessing Syndesmotic Stability? A Systematic Review of Morphometric Studies

Incisura fibularis (IF) is an important landmark in assessing syndesmotic stability radiologically postinjury. The purpose of this review was to explore the anatomy and morphometrics of this widely used anatomical landmark and to further the understanding of the same. A systematic review was conducted online using PubMed and Google Scholar, per PRISMA guidelines. Predefined eligibility criteria were applied, and the data thus compiled were analyzed. Wide variability in morphometrics and, thus, anatomy of IF were observed in the present review, which was influenced by gender. There was no side-to-side variability seen in this study. The study stresses the need to consider the anatomical and gender-based variability while assessing syndesmotic stability and further supports the recommendation of side-to-side comparison.

LEVELS OF EVIDENCE

Anatomical, Level V.

Management of acute injuries of the tibiofibular syndesmosis

The syndesmosis is important for ankle stability and load transmission and is commonly injured in association with ankle sprains and fractures. Syndesmotic disruption is associated with between 5 and 10% of ankle sprains and 11-20% of operative ankle fractures. Failure to recognize and appropriately treat syndesmotic disruption can portend poor functional outcomes for patients; therefore, early recognition and appropriate treatment are critical. Syndesmotic injuries are difficult to diagnose, and even when identified and treated, a slightly malreduced syndesmosis can lead to joint destruction and poor functional outcomes. This review will discuss the relevant anatomy, biomechanics, mechanism of injury, clinical evaluation, and treatment of acute injuries to the ankle syndesmosis.

Syndesmosis injuries in the pediatric and adolescent athlete: an analysis of risk factors related to operative intervention

PURPOSE

To review all paediatric ankle syndesmotic injuries occurring at our institution and identify risk factors associated with operative intervention.

METHODS

Among 22 873 evaluations for ankle trauma, we found 220 children suffering from syndesmotic injuries (incidence: 0.96%). We recorded demographic data, details of the injury, features on examination and treatment variables. Univariable and multivariable logistic regression modelling was performed to identify risk factors associated with operative intervention.

RESULTS

The mean age at injury was 15.8 years (8.9 to 19.0) with a median follow-up of 13 weeks (IQR 5 to 30 weeks). A sports-related injury was most common (168/220, 76%). A total of 82 of 220 (37%) patients underwent operative fixation, of which 76 (93%) had an associated fibular fracture. Patients undergoing surgery had a higher incidence of swelling and inability to weight bear (p < 0.001). Statistically significant differences were recorded in tibiofibular (TF) clear space, TF overlap and medial clear space (MCS) between the operative and non-operative cohorts (6.0 vs 4.6 mm (p = 0.002), 5.4 vs 6.9 mm (p = 0.004) and 6.4 vs 3.5 mm (p < 0.001)). Multivariable analysis revealed patients with a fracture of the ankle had 44 times the odds of surgical intervention, patients with a closed physis had over five times the odds of surgical intervention and patients with a medial clear space greater than 5 mm had nearly eight times the odds of requiring surgical intervention.

CONCLUSIONS

Operative ankle syndesmotic injuries in the paediatric population are often associated with a closed distal tibial physis and concomitant fibular fracture.

Tibiofemoral syndesmosis injury treated by temporary screw fixation and ligament repair

INTRODUCTION

Tibiofemoral syndesmosis injuries are common but have not been extensively researched. The primary objective of this study was to evaluate the outcomes after temporary screw fixation with ligament repair of these injuries. The secondary objective was to look for factors that could impact these outcomes. We hypothesised that this double fixation (screw+suture) would lead to good outcomes with minimal secondary opening of the syndesmosis upon screw removal.

MATERIAL AND METHODS

This was a retrospective study of 285 patients with a tibiofemoral syndesmosis injury (01/2004-12/2011) who were treated by temporary tricortical or quadricortical screw fixation and ligament repair. The operated leg was unloaded for 6-8 weeks postoperative with the patient wearing a walking cast. The screw was removed in all patients before weight bearing was allowed. At follow-up, the range of motion, return to sports, pain, and functional scores (AOFAS and OMAS) were determined, and a radiological assessment was performed.

RESULTS

One hundred twenty-six patients were reviewed after a mean follow-up of 5.9±5.7years (2.9-10.5). Mean plantarflexion was 95% of the contralateral side and mean dorsiflexion was 93%. Return to sports occurred after a mean of 10weeks; 83% of patients returned to their pre-injury level of participation. Pain on VAS was 0.8/10 on average. The mean AOFAS and OMAS scores were both above 90 points. At the review, 4% of screws had broken. Diastasis was found in 5.6% of cases, osteoarthritis in 6.3% and an osteophyte in 11.1% of cases, but with no clinical repercussions. No risk factors were identified.

DISCUSSION AND CONCLUSION

Treatment by temporary screw fixation and ligament repair leads to good objective results, confirming our hypothesis. However, there is little published data and no consensus on the fixation method or the need to remove the screw.

LEVEL OF EVIDENCE

IV, retrospective, non-comparative.

Role of Ankle Arthroscopy in Management of Acute Ankle Fracture

PURPOSE

To report the operative findings of ankle arthroscopy during open reduction and internal fixation of acute ankle fractures.

METHODS

This was a retrospective review of 254 consecutive patients with acute ankle fractures who were treated with open reduction and internal fixation of the fractures, and ankle arthroscopy was performed at the same time. The accuracy of fracture reduction, the presence of syndesmosis disruption and its reduction, and the presence of ligamentous injuries and osteochondral lesions were documented. Second-look ankle arthroscopy was performed during syndesmosis screw removal 6 weeks after the key operation.

RESULTS

There were 6 patients with Weber A, 177 patients with Weber B, 51 patients with Weber C, and 20 patients with isolated medial malleolar fractures. Syndesmosis disruption was present in 0% of patients with Weber A fracture, 52% of patients with Weber B fracture, 92% of patients with Weber C fracture, and 20% of the patients with isolated medial malleolar fracture. Three patients with Weber B and one patient with Weber C fracture have occult syndesmosis instability after screw removal. Osteochondral lesion was present in no patient with Weber A fracture, 26% of the Weber B cases, 24% of the Weber C cases, and 20% of isolated medial malleolar fracture cases. The association between the presence of deep deltoid ligament tear and syndesmosis disruption (warranting syndesmosis screw fixation) in Weber B cases was statistically significant but not in Weber C cases. There was no statistically significant association between the presence of posterior malleolar fracture and syndesmosis instability that warrant screw fixation.

CONCLUSIONS

Ankle arthroscopy is a useful adjuvant tool to understand the severity and complexity of acute ankle fracture. Direct arthroscopic visualization ensures detection and evaluation of intra-articular fractures, syndesmosis disruption, and associated osteochondral lesions and ligamentous injuries.

LEVEL OF EVIDENCE

Level IV, case series.

Clinical Adaptation of the "Tibiofibular Line" for Intraoperative Evaluation of Open Syndesmosis Reduction Accuracy: A Cadaveric Study

BACKGROUND

The "tibiofibular line" is a new axial computed tomography parameter for assessing syndesmosis reduction, which references the flat anterolateral surface of the fibula and anterolateral tibial tubercle. These same bony landmarks are easily visualized via a lateral approach to the fibula. This cadaveric study assessed the practical aspects of measuring the tibiofibular line intraoperatively.

METHODS

Three observers simulated the tibiofibular line using operative rulers in 3 measurement series utilizing 10 cadaveric specimens: intact syndesmosis, syndesmosis reduction, and fixation after application of lateral plate and screws to the fibula, and post syndesmosis reduction and fixation without plate and screws.

RESULTS

The majority (78%) of clinical tibiofibular line measurements were within the "normal" range (0-2 mm). However, there was a general trend toward malreduction (>2 mm) across measurement series. Intraobserver variability ranged from poor to excellent (intraclass correlation range, 0.12-0.85, Fleiss kappa range, 0.19-0.40) and interobserver reliability was only generally in the fair range (intraclass correlation range, 0.49-0.61; Fleiss kappa range, 0.19-0.40).

CONCLUSION

Taken as a whole, these findings found that the technique was feasible but clearly indicated that further refinement of this protocol, including the use of computed tomography, would be needed to determine if better control of confounding variables would reveal better observer reliability.

CLINICAL RELEVANCE

The CT-based TFL technique for syndesmosis reduction assessment could not reliably be translated into an intraoperative open technique because of the confounding effects of subjectivity and operator error.

Correlation and comparison of syndesmosis dimension on CT and MRI

INTRODUCTION

Various methods using CT scan have been described to diagnose distal tibiofibular syndesmotic injuries. However, CT scan does not take into account the amount of cartilage within the distal tibiofibular joint and could therefore lead to false positive results. We present the first study correlating the findings of the distal tibiofibular syndesmosis on CT and MRI scans.

METHODS

CT and MRI scan of consecutive patients over a period of 18 months, and of a time lapsed less than 12 months between the two imaging modalities, were reviewed. Measurements of the distal tibiofibular syndesmosis were taken according to a previously published study at the level of the distal tibial physeal scar.

RESULTS

Twenty-six ankles from 25 patients were included in this study for analysis. Significant difference between CT and MRI assessments in the overall distal tibiofibular dimensions and in the posterior distal tibiofibular distance for those ankles with evidence of osteoarthritis was found. Interclass correlation coefficients suggest that such methodology was reproducible and reliable.

CONCLUSION

When the widening found on a CT scan is minor or the diagnosis is equivocal, a contralateral comparative CT or an ipsilateral MRI scan is recommended to prevent misdiagnosis.

LEVEL OF EVIDENCE

Level IV.

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.

Increased Reduction Clamp Force Associated With Syndesmotic Overcompression

BACKGROUND

The distal tibiofibular syndesmosis is disrupted in up to 45% of operatively treated ankle fractures, and syndesmotic malreduction has historically been correlated with poor outcome. The purpose of this study was to quantify the clamp force used during syndesmotic reduction and to evaluate the effect of clamp force on fibular overmedialization (overcompression) at the level of the distal tibiofibular syndesmosis.

METHODS

A prospectively recruited cohort of 21 patients underwent operative syndesmotic reduction and fixation. A ball point periarticular reduction forceps that was modified to include a load cell in one tine was used for the reduction, and the clamp force required for reduction was measured. Patients underwent postoperative bilateral computed tomographic scans of the ankle and hindfoot to assess syndesmotic reduction. The uninjured extremity was used as a control. Side-to-side differences in fibular medialization, translation, and rotation within the tibial incisura were measured. These findings were correlated with the reduction clamp force utilized to obtain the reduction.

RESULTS

Syndesmotic overcompression (fibular medialization greater than 1.0 mm when compared with noninjured ankle) was seen in 11 of 21 patients (52%). Increased clamp force significantly correlated with syndesmotic overcompression. The mean reduction clamp forces were 88 N for the undercompressed group, 130 N for the adequately compressed group, and 163 N for the overcompressed group.

CONCLUSION

This study demonstrated a significant correlation between increased clamp forces and syndesmotic overcompression, and determined objective forces that lead to overcompression. Our results indicate that surgeons should be cognizant of the clamp force used for syndesmotic reduction.

LEVEL OF EVIDENCE

Level III, case-control series, in accordance with STROBE guidelines.

Management of Syndesmotic Ankle Injuries in Children and Adolescents

Pediatric ankle injuries are common, especially in athletes; however, the incidence of syndesmosis injuries in children has been scarcely reported. Injuries to the ankle syndesmosis, termed "high ankle sprains," can affect high-level and recreational athletes and have been related to delayed return to play, persistent pain, and adult injuries have been associated with long-term disability. Syndesmotic injuries do occur in children, especially those who participate in sports that involve cutting and pivoting (football, soccer) or sports with rigid immobilization of the ankle (skiing, hockey). Unstable pediatric syndesmosis injuries requiring surgical fixation are often associated with concomitant fibular fracture in skeletally mature children. Physician vigilance and careful clinical examination coupled with appropriate radiographs can determine the extent of the injury in the majority of circumstances.

Effects of inferior tibiofibular syndesmosis injury and screw stabilization on motion of the ankle: a finite element study

PURPOSE

Traditional studies of syndesmosis injury and screw stabilization have been conducted in cadaveric models, which cannot yield sufficient and exact biomechanical data about the interior of the ankle. The purpose of this study was to evaluate the effects of inferior tibiofibular syndesmosis injury (ITSI) and screw stabilization on the motion of the ankle with finite element analysis.

METHODS

Three-dimensional models of the ankle complex were created with CT images of a volunteer's right ankle in three states: normal, post-ITSI, and stabilization with a screw 2.5 cm above (parallel to) the ankle. Simulated loads were applied under three conditions: neutral position with single foot standing, internal rotation, and external rotation of the ankle.

RESULTS

Compared with the normal state, ITSI increased the relative displacement between the lower extremes of the tibia and fibula in the anteroposterior and mediolateral directions and the angular motion of the tibia, fibula, and talus at internal and external rotations (ERs). However, when stabilized with syndesmotic screws, the range of motion (ROM) and all these parameters significantly decreased.

CONCLUSION

ITSI can lead to internal and ER instability of the ankle joint. Screw stabilization is effective in controlling the instability, but may reduce markedly the ROM of the ankle joint. Through this study, it can be proposed that the screws should be removed once the healing is gained in order to restore normal function of the ankle joint as soon as possible.

Targeted computerised tomography scanning of the ankle syndesmosis with low dose radiation exposure

OBJECTIVES

To devise a new protocol for targeted CTscanning of the distal tibiofibular syndesmosis with minimal radiation exposure to patients. We also aimed to correlate the reduction of the syndesmosis as seen on CT scans with the functional outcome of patients.

MATERIALS AND METHODS

Prospective study. Forty adults undergoing surgical stabilisation of an acute distal tibiofibular syndesmosis injury were recruited. A targeted five-cut computerised tomography scan protocol was developed. The radiation exposure to the patient with this protocol was only 0.002 mSv. Scans were performed 12 weeks after surgery. The contralateral ankle of every patient was used as a control to determine the accuracy of the reduction of the syndesmosis for that individual patient. American Orthopaedic Foot and Ankle Society (AOFAS) scores were obtained at a minimum of 1 year after surgery.

RESULTS

After considering the exclusions, 36 patients formed the study group. A wide variation was observed in the anatomy of the normal syndesmosis. If we considered a difference of more than 2 mm between the normal and injured syndesmosis relationship as significant, 15 (41.6 %) of our patients had a significant difference between the injured and normal sides. AOFAS scores were available for 13 of these patients and were good to excellent in 11(84.6 %).

CONCLUSION

Our study describes a reliable new CT scanning technique for the distal tibiofibular syndesmosis using only five cuts and a low-radiation-dose protocol. Clinical correlation of the findings on the scan with functional outcomes suggests that routine post-operative CT of the syndesmosis is probably not justified.

Outcomes and Return to Activity After Operative Repair of Chronic Latent Syndesmotic Instability

BACKGROUND

This study is a retrospective review of prospectively gathered data determining the postoperative outcomes of patients who underwent operative treatment to address chronic syndesmotic instability.

METHODS

The cohort is composed of 19 individuals who elected to undergo operative treatment of chronic syndesmotic instability. The operative repair consisted of arthroscopic debridement in all cases with reduction and suture button fixation of those patients who had greater than 4 mm of syndesmotic diastasis on arthroscopic evaluation. All patients had a minimum of 24 months follow-up. This study retrospectively examined the prospectively gathered preoperative and postoperative outcome scores to include a Visual Analog Scale (VAS) pain score and an American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score. In addition, patients were questioned on their ability to return to their preinjury level of activity and their ability to continue running sports. Fourteen patients returned their postoperative surveys.

RESULTS

Mean AOFAS scores improved significantly from 48 to 82.7 (P = .014). Mean VAS scores improved from 6.1 to 1.0 (P = .002). Overall, 86% (12/14) of patients were able to return to running and 79% (11/14) of patients were able to return to their preinjury level of sport. Preoperative and postoperative weight-bearing ankle radiographs were reviewed to evaluate the tibiofibular clear space and overlap. The clear space measured on anteroposterior (AP) radiographs decreased from 5.4 mm to 4.6 mm (P = .005), the clear space evaluated on the mortise radiograph decreased from 4.5 mm to 3.6 mm (P = .006), and the overlap measured on the AP radiograph increased from 5.7 mm to 6.9 mm (P = .019). All radiographs were measured by a board-certified musculoskeletal radiologist.

CONCLUSION

This study presents a treatment method that can be instituted at the time of diagnosis for syndesmotic injuries with greater than 4 mm of diastasis that were treated with debridement and stabilization. The results of this treatment technique are promising, with significant improvements in subjective outcome scores and a high rate of return to running sports.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

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.

A reliable radiographic measurement for evaluation of normal distal tibiofibular syndesmosis: a multi-detector computed tomography study in adults

Background

Syndesmotic injury may be difficult to diagnose, and radiological evaluation is very important. The purpose of this study was to offer a series of reliable and repeatable normal tibiofibular syndesmosis parameters in diagnosing injuries of the syndesmosis.

Methods

Multi-detector computed tomography (MDCT) and radiographs of the distal tibiofibular syndesmosis in 484 cases were retrospectively reviewed. Relevant parameters included the tibiofibular clear space (TCS), the tibiofibular overlap (TFO), the depth of the incisura fibularis (IFD), and the height of the incisura fibularis (IFH), which were measured by novel three-dimensional (3-D) and two-dimensional (2-D) techniques. The distance between the measuring plane of the distal tibiofibular syndesmosis and the tibial plafond was measured. Intra- and inter-rater reliability was assessed by intraclass correlation coefficient (ICC) and the root mean square standard deviation (RMS-SD), to determine measurement precision. Sex differences of parameters were analyzed using analysis of covariance (ANCOVA) with body height as the covariate. Paired sample t-testing was used to compare parameters in different image modalities, including radiography, and 2-D and 3-D CT.

Results

The reliability of the 3-D images measurement (ICC range, 0.907 to 0.972) was greater than that for the 2-D axial images (ICC range, 0.895 to 0.927), and the AP view radiographs (ICC range, 0.742 to 0.838). The intra-rater RMS-SD of the 3-D CT, 2-D CT and radiographic measurements were less than 0.94 mm, 0.26 mm, and 2.87 mm, respectively. The measuring plane of the distal tibiofibular syndesmosis showed the sex difference, which was 12.1 mm proximal to the tibial plafond in the male group and 7.8 mm in the female group. In this plane, the parameters for tibiofibular syndesmosis were measured in different image modalities. All variables were significantly different between females and males (p < 0.05).

Conclusions

3-D measurement technique could be helpful to identify the precise measurement planes for syndesmosis, which were not at the fixed level above the tibial plafond because of the sex difference. In this plane, reliable measurement results could be provided, in either 2-D or 3-D MDCT images.

Electronic supplementary material

The online version of this article (doi:10.1186/s13047-015-0093-6) contains supplementary material, which is available to authorized users.

Can pre-operative axial CT imaging predict syndesmosis instability in patients sustaining ankle fractures? Seven years' experience in a tertiary trauma center

OBJECTIVE

The purpose of this study is to explore the diagnostic accuracy of CT measurements in predicting syndesmosis instability of injured ankle, with correlation to operative findings.

METHODS

From July 2006 to June 2013, 123 patients presented to a single tertiary hospital who received pre-operative CT for ankle fractures were retrospectively reviewed. All patients underwent open reduction and internal fixation for fractures and intra-operative syndesmosis integrity tests. The morphology of incisura fibularis was categorized as deep or shallow. The tibiofibular distance (TFD) between the medial border of the fibula and the nearest point of the lateral border of tibia were measured at anterior (aTFD), middle (mTFD), posterior (pTFD), and maximal (maxTFD) portions across the syndesmosis on axial CT images at 10 mm proximal to the tibial plafond. Statistical analysis was performed with independent samples t test and ROC curve analysis. Intraobserver reproducibility and inter-observers agreement were also evaluated.

RESULTS

Of the 123 patients, 39 (31.7%) were operatively diagnosed with syndesmosis instability. No significant difference of incisura fibularis morphology (deep or shallow) and TFDs was demonstrated respective to genders. The axial CT measurements were significantly higher in ankles diagnosed with syndesmosis instability than the group without (maxTFD means 7.2 ± 2.96 mm vs. 4.6 ± 1.4 mm, aTFD mean 4.9 ± 3.7 mm vs. 1.8 ± 1.4 mm, mTFD mean 5.3 ± 2.4 mm vs. 3.2 ± 1.6 mm, pTFD mean 5.3 ± 1.8 mm vs. 4.1 ± 1.3 mm, p < 0.05). Their respective cutoff values with best sensitivity and specificity were calculated; the aTFD (AUC 0.798) and maxTFD (AUC 0.794) achieved the highest diagnostic accuracy. The optimal cutoff levels were aTFD =  mm (sensitivity, 56.4%; specificity, 91.7%) and maxTFD = 5.65 mm (sensitivity, 74.4%; specificity, 79.8%). The inter-observer agreement was good for all aTFD, mTFD, pTFD, and maxTFD measurements (ICC 0.959, 0.799, 0.783, and 0.865). The ICC for intraobserver agreement was also very good, ranging from 0.826 to 0.923.

CONCLUSIONS

Axial CT measurements of tibiofibular distance were useful predictors for syndesmosis instability in fractured ankles. The aTFD and maxTFD are the most powerful parameters to predict positive operative instability.

A prospective randomized multicenter trial comparing clinical outcomes of patients treated surgically with a static or dynamic implant for acute ankle syndesmosis rupture

OBJECTIVES

To compare the clinical and radiographic outcome after stabilization of an acute syndesmosis rupture with either a static implant (a 3.5-mm metallic screw through 4 cortices) or a dynamic device (TightRope; Arthrex).

DESIGN

Multicenter randomized double-blind controlled trial.

SETTINGS

Study realized in 5 trauma centers (2 level 1 and 3 level 2) in 2 countries.

PATIENTS/PARTICIPANTS

Seventy subjects admitted for an acute ankle syndesmosis rupture entered the study and were randomized into 2 groups (dynamic fixation = 34 and static fixation = 36). The 2 groups were similar regarding demographic, social, and surgical data. Sixty-five patients (dynamic = 33 and static = 32) completed the study and were available for analysis.

INTERVENTION

Syndesmosis fixation in the static group was realized with a 4 cortices 3.5-mm cortical screw (Synthes) and in the dynamic group with 1 TightRope (Arthrex). Standardized rehabilitation process for the 2 groups: no weight bearing in a cast for 6 weeks and then rehabilitation without protection.

MAIN OUTCOME MEASUREMENT

Olerud-Molander score.

RESULTS

Subjects with dynamic fixation achieved better clinical performances as described with the Olerud-Molander scores at 3 (68.8 vs. 60.2, P = 0.067), 6 (84.2 vs. 76.8, P = 0.082), and 12 months (93.3 vs. 87.6, P = 0.046). We also observed higher American Orthopaedic Foot and Ankle Society scores at 3 months (78.6 vs. 70.6, P = 0.016), but these were not significant at 6 (87.1 vs. 83.8, P = 0.26) or 12 months (93.1 vs. 89.9, P = 0.26). Implant failure was higher in the screw group (36.1% vs. 0%, P < 0.05). Loss of reduction was observed in 4 cases in the static screw group (11.1% vs. 0%, P = 0.06).

CONCLUSIONS

Dynamic fixation of acute ankle syndesmosis rupture with a dynamic device seems to result in better clinical and radiographic outcomes. The implant offers adequate syndesmotic stabilization without failure or loss of reduction, and the reoperation rate is significantly lower than with conventional screw fixation.

LEVEL OF EVIDENCE

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

Mid-term results of ankle fractures with and without syndesmotic rupture

BACKGROUNDS

This study investigated the effect of short term removal of syndesmotic screws on the ankle function after 6 years, as there still exists controversy on the duration of screw stabilization.

METHODS

Patients with an ankle fracture who received surgery between 1998 and 2004 were reviewed. One group was composed of patients with an ankle fracture needing a syndesmotic repair with screws. The second was composed of operated patients that did not need syndesmotic repair. The primary scoring used was the Olerud-Molander Ankle Score (OMAS).

RESULTS

A total of 59 patients were studied with comparable characteristics, with no significant difference on the OMAS after 6 years between the repair group (81.9) and the non-repair group (90.4). On additional clinical scoring groups remained the same. Joint degeneration was seen in both groups (86.7% vs. 55.5%).

CONCLUSIONS

Patients with ankle fractures using syndesmotic repair and screw removal after 8 weeks and operated patients without syndesmotic injury have comparable results after 6 years.

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.

An update on the evaluation and treatment of syndesmotic injuries

INTRODUCTION

Injuries to the distal tibiofibular syndesmosis are frequent and continue to generate controversy.

METHODS

The majority of purely ligamentous injuries ("high ankle sprains") is not sassociated with a latent or frank tibiofibular diastasis and may be treated with an extended protocol of physical therapy. Relevant instability of the syndesmosis with diastasis results from rupture of two or more ligaments that require surgical stabilization. Syndesmosis disruptions are commonly associated with bony avulsions or malleolar fractures. Treatment consists in anatomic reduction of the distal fibula into the corresponding incisura of the distal tibia and stable fixation. Proposed means of fixation are refixation of bony syndesmotic avulsions, one or two tibiofibular screws and suture button. There is no consensus on how long to maintain fixation. Both syndesmotic screws and suture buttons need to be removed if symptomatic.

RESULTS/COMPLICATIONS

The most frequent complication is syndesmotic malreduction and may be minimized with open reduction and intraoperative 3D scanning. Other complications include hardware failure, heterotopic ossification, tibiofibular synostosis, chronic instability and posttraumatic arthritis.

CONCLUSION

The single most important prognostic factor is anatomic reduction of the distal fibula into the tibial incisura.

The tibiofibular line: an anatomical feature to diagnose syndesmosis malposition

BACKGROUND

Medical imaging of the distal tibiofibular joint requires reliable and simple tools to identify disruption of the syndesmosis. We present an anatomical feature, the "tibiofibular line," which appears on axial computed tomography (CT) images of normal ankles. This feature is a straight line that connects the anterolateral surface of the fibula with the anterolateral tubercle of the tibia at the level of the ankle syndesmosis. The purpose of this study was, first, to demonstrate that this line is a reliable anatomical feature in normal ankles and, second, to demonstrate that this line is displaced with diastasis or malrotation of the syndesmosis.

METHODS

A series of 150 normal ankle CTs were collected, negative for history of ankle injury with a normal tibiofibular overlap and clear space. Thirty ankles with a displaced syndesmosis were identified by history, CT, and abnormal tibiofibular overlap and clear space parameters. The tibiofibular line was applied to both groups and measured for its distance displaced from the anterior tibial tubercle.

RESULTS

All CT images in the normal ankle group had a tibiofibular line within 2 mm of the anterior tibial tubercle (77% of the tibiofibular lines were within 0 mm, 19% were within 1 mm, and 4% were within 2 mm). The tibiofibular line in the injured group was displaced anteriorly by 4 to 19 mm (minimum to maximum) from the tibial tubercle (P < .0001).

CONCLUSION

The tibiofibular line was a normal anatomical feature that could be used to identify displacement of the distal tibiofibular syndesmosis.

LEVEL OF EVIDENCE

Level III, comparative series.

Fibular malalignment in individuals with chronic ankle instability

STUDY DESIGN

Case series.

OBJECTIVES

To determine whether abnormal fibular alignment is present in individuals with chronic ankle instability (CAI) using 3-D analysis of computed tomography (CT)-based bone models.

BACKGROUND

A positional difference of the distal fibula in individuals with unilateral CAI, when compared to the contralateral side, has been suggested. However, previous studies report no consistent pattern of fibular malalignment in the anteroposterior direction and, to our knowledge, no study has investigated mediolateral malalignment.

METHODS

Seventeen males with unilateral CAI (mean ± SD age, 21.0 ± 2.4 years) and no history of injury in the contralateral side were enrolled. Geometric bone models of the tibia and fibula were created from non-weight-bearing CT images, and anatomical coordinate systems were embedded in the tibia model. Bilateral tibiae were superimposed using a best-fit algorithm that moved the tibia to the position of best congruity, and the amount of side-to-side difference in position of the fibulae was measured. The anteroposterior and mediolateral positional difference of the fibula of the ankle with CAI relative to the contralateral ankle, for the distal 10 cm of the fibula length, was determined using a color-coded map.

RESULTS

The fibula of the ankle with CAI was significantly more lateral (0.57-0.68 mm) than that of the contralateral healthy ankle at all reference points from distal 10 cm to the lateral malleolus. There was no significant difference in anteroposterior position between the healthy ankles and those with CAI.

CONCLUSION

This study detected malalignment of the distal fibula in ankles with CAI in a non-weight-bearing position. The fibula of the ankles with CAI had a significantly more lateral position than that of the healthy ankles, which may contribute to recurrent lateral ankle sprain or giving-way episodes.

Evaluation and treatment recommendations for acute injuries to the ankle syndesmosis without associated fracture

Ankle ligamentous injuries are commonly seen in athletes in a variety of sports. Surveys of physicians and trainers of professional sports teams have identified syndesmotic injuries as among the most difficult to treat. In particular, injuries of the ankle syndesmosis have been strongly linked with a prolonged recovery and increased time to return to play. Due to sudden external rotation with the tibiotalar joint in dorsiflexion, these structures are commonly injured in association with fractures of the distal fibula. Surgery is indicated in cases with associated fractures and ligamentous instability, but optimal treatment for syndesmosis injuries without an associated fracture is less clear. A thorough history and physical examination, as well as appropriate imaging, are necessary to effectively diagnose and classify the injury. For stable injuries, short-term immobilization and functional rehabilitation is recommended. Unstable Grade 2 and 3 injuries require surgical fixation. Debate currently exists over rigid screw fixation versus suture button techniques as the ideal fixation method.

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.

The lambda sign: a new radiographic indicator of latent syndesmosis instability

BACKGROUND

Latent syndesmotic instability is a common cause of chronic ankle pain. The diagnosis is not readily apparent on static imaging as the fibula remains reduced. The hypothesis of this study was that a previously undescribed novel finding on coronal MRI (lambda sign) is an independent indicator of latent syndesmosis instability. We also report on the utility of classic radiographic and physical exam findings.

METHODS

A total of 23 patients with latent syndesmotic instability diagnosed via arthroscopy (group I) were compared to a cohort of 40 patients who were found to have a stable syndesmosis during arthroscopy for unrelated conditions (group II). A retrospective chart review was performed evaluating their clinical history, preoperative physical examination, and radiologic findings. The lambda sign is a high intensity signal seen on coronal MR imaging that resembles the Greek letter lambda.

RESULTS

All of the physical exam findings tested were statistically significant. Pain at the syndesmosis had the highest sensitivity (83%), while pain reproduced with the proximal squeeze test resulted in the highest specificity (89%). The external rotation stress test had the highest positive predictive value (75%). Of the radiographic examinations performed, only the lambda sign was found to have statistical significance with a sensitivity of 75% and a specificity of 63%. The presence of a lambda sign on the MRI of patients with physical exam findings suggestive of syndesmotic pain was highly sensitive (75%) and specific (85%).

CONCLUSION

The lambda sign noted on the coronal MRI was both sensitive and specific for injuries involving greater than 2 mm of diastasis on arthroscopic stress examination of the syndesmosis. While neither the lambda sign nor any other finding on physical or radiographic examination represented an independent predictor of syndesmotic instability, the presence of a lambda sign in concert with positive physical exam findings might help health care providers determine which patients might benefit from operative intervention or referral.

LEVEL OF EVIDENCE

Level III, case control study.

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.

Posterior translation of the fibula may indicate malreduction: CT study of normal variation in uninjured ankles

OBJECTIVES

The aim of our study was to assess the intersubject and intrasubject variations of distal tibiofibular syndesmosis on computed tomography (CT) scans and to define standardized measures to verify syndesmosis reduction.

DESIGN

A retrospective study of 107 CT scans of ankles with normal tibiofibular syndesmosis.

SETTING

Main trauma center, university teaching hospital.

PATIENTS

The CT scans of 64 patients were reviewed by 2 musculoskeletal radiologists.

MAIN OUTCOME MEASUREMENTS

Bilateral variation was estimated. The intra- and interobserver reliabilities were calculated using standardized measurement points. CT measurements included the length of the tibial incisura (LI), A width and P width of the incisura (PW), depth of the incisura, narrowest part of the incisura, and sagittal translation of the fibula.

RESULTS

In 97% of normal cases, the fibula is situated either centrally or anteriorly in the tibial incisura. There were significant differences in PW and LI between genders, and the difference between the PW and A width was significantly larger in males (2.7 mm, SD 2.1) than in females (1.9 mm, SD 1.6, P = 0.023, t test). Significant asymmetry was not detected between ankles in single subjects. All CT measurements demonstrated good inter- and intraobserver reliabilities.

CONCLUSIONS

If P translation of the fibula is present, malreduction should be considered. Sagittal translation measurements are not affected by the size of the joint or the gender of the patient, in contrast to traditionally used cross-sectional measurement methods.

Analysis of the stress and displacement distribution of inferior tibiofibular syndesmosis injuries repaired with screw fixation: a finite element study

BACKGROUND

Studies of syndesmosis injuries have concentrated on cadaver models. However, they are unable to obtain exact data regarding the stress and displacement distribution of various tissues, and it is difficult to compare models. We investigated the biomechanical effects of inferior tibiofibular syndesmosis injuries (ITSIs) and screw fixation on the ankle using the finite element (FE) method.

METHODOLOGY/PRINCIPAL FINDINGS

A three-dimensional model of a healthy ankle complex was developed using computed tomography (CT) images. We established models of an ITSI and of screw fixation at the plane 2.5 cm above and parallel to the tibiotalar joint surface of the injured syndesmosis. Simulated loads were applied under three conditions: neutral position with single-foot standing and internal and external rotation of the ankle. ITSI reduced contact forces between the talus and fibula, helped periarticular ankle ligaments withstand more load-resisting movement, and increased the magnitude of displacement at the lower extreme of the tibia and fibula. ITSI fixation with a syndesmotic screw reduced contact forces in all joints, decreased the magnitude of displacement at the lower extreme of the tibia and fibula, and increased crural interosseous membrane stress.

CONCLUSIONS/SIGNIFICANCE

Severe syndesmosis injuries cause stress and displacement distribution of the ankle to change multidirectional ankle instability and should be treated by internal fixation. Though the transverse syndesmotic screw effectively stabilizes syndesmotic diastasis, it also changes stress distribution around the ankle and decreases the joint's range of motion (ROM). Therefore, fixation should not be performed for a long period of time because it is not physiologically suitable for the ankle joint.

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.

[Intraoperative 3-dimensional imaging - beneficial or necessary?]

BACKGROUND

With reference to two large retrospective studies we would like to make a contribution to the discussion whether intraoperative 3-dimensional imaging is only a helpful tool or state of the art for some special indications.

METHODS

To answer this question the intraoperative revision rates of syndesmotic injuries and calcaneal fractures were analyzed over a period of 10 years and 8 years, respectively. Additionally, the clinical outcome was evaluated depending on the restoration of the joint reconstruction.

RESULTS

Intraoperative revision rates of 32.7 % of 251 syndesmotic injuries and 40.3 % of 377 calcaneal fractures were found. The mutivariate analysis showed that residual joint incongruity leads to significantly worse clinical and radiological outcome of calcaneal fractures.

CONCLUSIONS

Correct assessment of alignment and joint line reconstruction are not possible by means of fluoroscopy in every case of syndesmotic injuries and calcaneal fractures. Therefore, intraoperative 3-dimensional imaging should be used in the treatment of these injuries due to the high intraoperative revision rates and the clinical relevance.

Time to return to play after high ankle sprains in collegiate football players: a prediction model

BACKGROUND

Determining the severity of high ankle sprains in athletes and predicting the time that an athlete can return to unrestricted sport activities following this injury remain significant challenges.

PURPOSE

The objectives of this study were (1) to determine if objective measurements of injury severity after high ankle sprains could predict the time to return to play in Division I football players and (2) to determine whether physical examination or diagnostic musculoskeletal ultrasound was more predictive of return to play. The hypothesis was that objective measures of injury severity of a high ankle sprain can be predictive of time to return to athletic participation in collegiate football players.

STUDY DESIGN

Prospective case series.

METHODS

Twenty consecutive Division I collegiate football players with a diagnosis of a grade I high ankle sprain (syndesmosis sprain without diastasis) were studied. Two clinical measurements of injury severity were determined: the height of the zone of injury on physical examination and the height of the zone of injury as defined by diagnostic musculoskeletal ultrasound examination. All athletes followed a standardized treatment program and return-to-play criteria. A regression model and Cox proportional hazards model were developed to determine time to return to unrestricted play as a function of injury severity and player position.

RESULTS

Physical examination but not ultrasound was significantly correlated with time to return to play. Regression and Cox analyses revealed that injury severity on physical examination and player position were significant predictors of time to return to unrestricted play following high ankle sprain.

CONCLUSIONS

Injury severity on physical examination and player position are associated with the time to return to unrestricted athletic activity after injury. A model based on the data can be applied to help predict the time to return to unrestricted play in Division I collegiate football players following high ankle sprain.

Syndesmosis and deltoid ligament injuries in the athlete

PURPOSE

Injury to the syndesmosis and deltoid ligament is less common than lateral ligament trauma but can lead to significant time away from sport and prolonged rehabilitation. This literature review will discuss both syndesmotic and deltoid ligament injuries without fracture in the professional athlete.

METHODS

A narrative review was performed using PUBMED, OVID, MEDLINE and EMBASE using the key words syndesmosis, injury, deltoid, ankle ligaments, and athlete. Articles related to the topic were included and reviewed.

RESULTS

The incidence of syndesmotic injury ranges from 1 to 18 % of ankle sprains. This may be underreported and is an often missed injury as clinical examination is generally not specific. Both MRI and ultrasonography have high sensitivities and specificities in diagnosing injury. Arthroscopy may confirm the diagnosis, and associated intra-articular pathology can be treated at the same time as surgical stabilization. Significant deltoid ligament injury in isolation is rare, there is usually associated trauma. Major disruption of both deep and superficial parts can lead to ankle dysfunction. Repair of the ligament following ankle fracture is not necessary, but there is little literature to guide the management of deltoid ruptures in isolation or in association with syndesmotic and lateral ligament injuries in the professional athlete.

CONCLUSION

Management of syndesmotic injury is determined by the grade and associated injury around the ankle. Grade I injuries are treated non-surgically in a boot with a period of non-weight bearing. Treatment of Grade II and III injuries is controversial with little literature to guide management. Athletes may return to training and play sooner if the syndesmosis is surgically stabilized. For deltoid ligament injury, grade I and II sprains should be treated non-operatively. Unstable grade III injuries with associated injury to the lateral ligaments or the syndesmosis may benefit from operative repair.

Management of syndesmosis injuries in the elite athlete

This article reviews the basics and evidence base thus far on syndesmosis injuries, focusing on its management in the elite sporting population. A syndesmosis injury or "high ankle sprain" is a significant injury, especially in the elite athlete. Among all ankle sprains, the syndesmotic injury is most predictive of persistent symptoms in the athletic population. Late diagnosis of unstable syndesmosis injuries leads to a poor outcome and delayed return to sports. A high index of suspicion and an understanding of the mechanism of injury is required to ensure an early diagnosis. Incomplete/inaccurate reduction leads to a poor outcome.