Complete Ankle Joint that is Tibiotalar and Distal Tibiofibular Coalition Presenting with Foot and Ankle Pain - A Case Report

Introduction

Coalition is an abnormal, usually congenital, or developmental connection in between or the complete fusion of two bones that are otherwise separate. It is of three types, i.e., synostosis (bony connection), synchondrosis (cartilaginous connection), or syndesmosis (fibrous tissue). Its typical cause is the failure of mesenchymal segmentation and differentiation. Usually, it is seen in tarsal or carpal bones and very rarely in between other bones. Only a single case of a tibiotalar coalition has been reported previously in literature. Herein, we are reporting a case of the talocrural coalition, which is the first one from the Indian sub-continent.

Case Report

A 16-year-old moderately built female patient of Indian origin presented with chronic pain of 1-year duration in the right foot and ankle region on weight bearing. The pain was dull aching type, mild-to-moderate in severity and worsened with activity or prolonged walking, and relieved on taking non-steroidal anti-inflammatory drugs. No relevant history was present. On local examination, diffuse tenderness was present in the ankle and the tarsal bones. Almost negligible dorsiflexion and about 15° plantar flexion of the foot were possible. An initial radiograph of the right ankle revealed osseous fusion between the distal tibia and fibula, as well as between the tibia, fibula, and the dome of the talus. Magnetic resonance imaging (MRI) revealed osseous fusion involving the distal tibia, fibula, and the dome of the talus (both medially and laterally), indicative of talocrural fusion. No edema or inflammation was appreciable in the adjacent tendons or synovium. The patient was explained regarding the pathology and the prognosis. She was managed conservatively and was satisfied.

Conclusion

Radiographs play a crucial role in evaluating patients suspected of having a coalition or ankylosis. Complementary tools such as computed tomography and MRI are valuable for a more in-depth assessment of the fusion and aid in surgical planning.

Measuring External Rotation of the Fibula and Fibular Length in Bilateral Computed Tomography Scans: How Reliable Is This Method?

OBJECTIVES

During ankle fracture surgery, goals include accurate reduction and fixation of the fibula regarding rotation and fibular length. Bilateral postoperative computed tomography (CT) can be performed to assess fibular rotation using the talar dome angle, and fibular length. The aim of this study was to compare side-to-side differences of the fibular rotation and fibular length using bilateral CT scans of uninjured ankles.

METHODS

DESIGN

Retrospective.

SETTING

Single center, Level I Academic Trauma Center.

PATIENT SELECTION CRITERIA

Patients with bilateral CT scans of uninjured ankles.

OUTCOME MEASURES AND COMPARISONS

External rotation using the Nault talar dome method and fibular length using the coronal method of Prior et al. The average, difference, and ratio (injured side/healthy side) and interobserver variability were calculated.

RESULTS

There were 83 patients included (166 ankles, mean age 47 years, 77.1% male). A random set of 66 ankles (33 CT scans) were used to measure interobserver variability. The mean degrees of external rotation ranged from 6.6 to 7.7, mean difference ranged from 1.4 to 3.4 degrees, mean ratio ranged from 1.1 to 1.5, and interobserver variability ranged from 0.27 to 0.65. For fibular length, the mean ranged from 24.6 to 25.8 mm, mean difference in fibular length ranged from 0.5 to 2.1 mm, mean ratio ranged from 1.0 to 1.1 mm, and interobserver variability ranged from 0.45 to 0.73.

CONCLUSIONS

Using bilateral ankle CT scans, mean differences in fibular rotation using the Nault talar dome method were 1.4-3.4 degrees. The distal fibular length had a mean difference between both sides of 0.5-2.1 mm. Although the intraclass correlation's were low, the interleg differences between patients were small, making them useful for clinical practice.

LEVEL OF EVIDENCE

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

Morphological Variations and Normal Parameters of the Cross-Sectional Anatomy of the Tibiofibular Syndesmotic

BACKGROUND

The aim of this study was to determine morphological variations and normal parameters of the cross-sectional tibiofibular syndesmotic anatomy.

METHODS

Configurations of syndesmosis, anterior syndesmotic width (ASW), posterior syndesmotic width (PSW), and overlap distance, defined as the overlap of medial fibula with a drawn line from tip of anterior tubercle of incisura fibularis to the posterior tip, were measured on normal computed tomography (CT) scans of 110 cases. Results: Seventy seven male (70%) and 33 female (30%) (left: 50 and right: 60) were assessed. Mean age of the cases was 33 ± 13 (range: 15-80) years. Three different syndesmotic configurations were crescent (55.5%), rectangular (39.1 %), and semicircle (5.4 %). Overall, mean ASW, PSW, and overlap distance were 2.72, 3.98, and 1.02 mm, respectively. Upper limit of normal ASW in crescent, rectangular, and semicircle was 4.80, 4.85, and 3.89 mm, respectively. The maximum of PSW in crescent, rectangular, and semicircle was 6.25, 6.50, and 4.97 mm, respectively. There was not significant difference between syndesmotic configurations based on age (P = .69) and sex (P = .16).

CONCLUSIONS

During interpreting axial CT scan to diagnose syndesmotic injuries, the normal range of parameters according to the different configurations of the tibiofibular syndesmosis should be carefully considered.

LEVEL OF EVIDENCE

Level 4.

The Radiological Anatomy of the Distal Tibiofibular Joint: A Retrospective Computed Tomography Study

Introduction Distal tibiofibular joint (DTFJ) injuries are commonly encountered in patients with ankle fractures. Achieving optimal fixation is mandatory, but it requires a thorough understanding of the local anatomical relationships. For this reason, we performed a retrospective CT study in healthy ankles to radiologically describe the normal anatomy of the DTFJ and the anatomical relationship of the fibula within the ankle joint. Materials and methods For this study, we retrospectively examined 60 CT scans of healthy, non-injured ankles in a plantigrade position. Patients with prior ankle surgery or systemic diseases with ankle involvement were excluded because we needed to describe the normal anatomy of the joint. The radiological evaluation included the position of the fibula in the fibular notch and the rotational relationship of the fibula with the talus and the medial malleolus. Results Our study included 60 healthy ankles. Thirty-three were right ankles, and 27 were left. The cohort included 36 females and 24 males with a mean age of 48.3 years old. We found that the fibular notch was retroverted on the transverse plane, with the tibiofibular engagement being 0.11 mm (SD=1.57 mm, SE=0.2 mm), at 1 cm proximally to the tibial plafond. Additionally, we observed that the fibula was internally rotated against the lateral talar facet, while the medial and lateral malleolus facets were externally rotated in between. Moreover, we found a strong positive correlation between the incisura retroversion and fibular engagement at 1 cm above the tibial plafond line (Pearson correlation=0.273, p=0.03). Conclusion Our study highlights the importance of gaining a comprehensive understanding of the inherent anatomy of the DTFJ to achieve reduction goals in ankle fractures. According to our results, in ankle fracture treatment, surgeons should aim for anatomical fracture and syndesmotic fixation, with the fibula in internal rotation against the lateral talar facet. Additionally, as normal tibiofibular engagement is borderline, we do not suggest that over-tightening the syndesmotic screws is essential. This study's findings can aid surgeons in reducing the malreduction rates in patients with ankle fractures.

Reliability of preoperative CT and intraoperative manual tests in syndesmosis injury

OBJECTIVE

We always confirm the diagnosis of syndesmotic injury with a Hook test for all ankle fractures and fixed if necessary. Then, we noticed a discrepancy between preoperative radiology and the Hook test. Moreover, we want to report the reliability of syndesmotic fixation decisions with Hook test and preoperative radiology.

METHODS

A total of 37 surgically treated patients with isolated Weber type C ankle fractures were included in the study. In all patients, the syndesmosis joint was injured in preoperative computed tomography and X-ray imaging. However, only patients with (+) Hook tests had undergone a syndesmosis fixation. Patients were divided into two groups: Group A: Hook tests (+) and Group B: Hook test (-). Also, the groups were compared according to clinical outcomes with the Visual Analog Scale (VAS), American Orthopedic Foot and Ankle Society (AOFAS), and foot and ankle disability index (FADI) scores.

RESULTS

The mean participant age was 39 (19-80) years, and the mean follow-up period was 47.27 (22-68) months. Groups A and B consisted of 17 (45.9%) and 20 (54.1%) patients, respectively. The mean VAS, AOFAS, and FADI scores were 17.7±14.3, 90.32±8.06, and 92.9±6.88, respectively. "Excellent" and "good" results were found in 34 (%91.8) patients according to AOFAS nad FADI. The malreduction rate was 8.1% in all patients, 5% in group A, and 11.8% in group B. No statistically significant differences in final functional scores were found between groups A and B.

CONCLUSION

Hook test is reliable and adequate for evaluating the stability and quality of syndesmosis reduction. Weber type C lateral malleolar fractures in the decision of syndesmosis fixation; although syndesmosis injury is diagnosed in preoperative radiology, we recommend that the diagnosis be confirmed with the Hook test.

A systematic review of studies on the diagnostics and classification system used in surgically treated, acute, isolated, unstable syndesmotic injury: a plea for uniform definition of syndesmotic injuries

Objective

To this day, diagnostic standards and uniform definition for acute, isolated syndesmotic injuries are missing. The aim of the current study was to conduct a systematic review of the classification systems and diagnostics currently applied and to propose a best evidence diagnostic approach.

Methods

Medline (PubMed), Scopus, Cochrane Central Register of Controlled Trials, and Embase were searched from inception to June 5, 2022, for studies reporting the outcome of surgically treated acute, isolated syndesmotic injuries. First, all classifications used in the eligible studies were identified and illustrated according to the individual syndesmotic structures injured. Second, the indication for surgery and stabilization, based on the diagnostics applied and the time point assessed (pre- or intra-operatively), was analyzed, including the applied cutoff criteria.

Results

Ten out of 4190 studies, comprising 317 acute ligamentous syndesmotic injuries, met the inclusion criteria. Seven studies facilitated one of the three different classification systems (Calder, West Point, or Sikka classification). Eight studies based their indication for surgery on a combination of clinical and radiographic examinations and two on radiographs only. The most applied clinical tests were the external rotation stress test and squeeze test. The most common radiologic diagnostics were plain radiographs and MRI. Intraoperatively, instability was verified most commonly using arthroscopy.

Conclusion

Current classifications and diagnostics for syndesmotic injuries are heterogeneous, often cannot be attributed to the ligaments injured. An evidence-based diagnostic algorithm based on noninvasive diagnostics and an anatomy-based classification for acute syndesmotic instability is presented.

Morphology of Fibular Incisura is a Deciding Factor Between Posterior Malleolus Avulsion Fracture or Syndesmotic Ligament Injury in Ankle Fractures

The bone anatomy of tibiofibular syndesmosis has been a topic of interest. Fibular incisura morphology has been analyzed on cadaver specimens, plain radiographs, or CT images. The aim of this study is to examine the effects of fibula incisura features and fibula morphology in ankle injuries, especially involving posterior malleolus and posteroinferior tibiofibular ligament injuries. From 2017 through 2022, A total of 59 patients with isolated lateral malleolar fracture, Mason-Malloy type 1 posterior malleolar fracture, syndesmosis injury in those without posterior malleolar fracture, supination external rotation type 3 injuries according to Lauge-Hansen classification, and preoperative bilateral ankle computed tomography images were included in the study. Fibula morphologies and syndesmosis measurements were made from preoperative computed tomography images using axial CT images from 1 cm proximal to the tibial plafond. The diagnosis of posterior malleolar fractures was made using the CT classification system of Mason and Malloy, and the diagnosis of syndesmosis injury was made with a cotton test during surgery. Age, gender, fractured side, incisura type, incisor depth, width, anterior and posterior facet lengths, incisor version (antevert-retrovert), the angle between the anterior and posterior facets, and fibula type were recorded. There was a statistically significant difference between the groups in posterior facet length and incisura width. Morphological features of fibular incisura may be the determinant of PITFL injury or PMA injury in fibular fractures caused by an external rotation mechanism.

Center-Center Surgical Technique With Dynamic Syndesmosis Fixation: A Cadaveric Pilot Study

The objective of this cadaveric biomechanical study was to evaluate if the center-center surgical technique is a reliable and repeatable method of achieving proper syndesmotic reduction when using dynamic syndesmotic fixation. Nine fresh frozen above-knee cadaveric lower extremities were used. Computerized tomography (CT) scans were first obtained for each intact specimen as the baseline for comparison. A simulated complete syndesmotic disruption was created by transection of all deltoid and syndesmotic ligaments. Instability of the ankle was confirmed with stress imaging using fluoroscopy. Each unstable specimen was repaired using the center-center surgical technique with dynamic syndesmosis fixation. A series of measurements from the axial CT images of intact and repaired specimens were used to determine the anatomic distal tibiofibular relationships for comparison of changes from intact to postfixation. All radiographic measurements were performed by 4 independent foot and ankle surgeons. The level of inter-rater reliability for all the measurements was found to be "moderate" to "excellent" agreement (ICC value: 0.865-0.983, 95% confidence interval: 0.634-0.996). There was no statistical difference found between rotational alignment of native and postfixation (a/b: p = .843; b-a: p = .125; θ: p = .062). There was a statistical difference detected for lateral alignment at the center of fibularis incisura between native and postfixation (average: -0.6 ± 0.8 mm, range: -2.3 to 1.2 mm, p < .001). There was no statistical difference found for the anteroposterior translation alignment between native and postfixation (d/e: p = .251; f: p = .377). This study demonstrated the use of the center-center surgical technique as a viable and repeatable method for achieving anatomical reduction of the tibiofibular syndesmosis when used with dynamic fixation modalities.

Normal Values for Distal Tibiofibular Syndesmotic Space With and Without Subject-Driven External Rotation Stress

BACKGROUND

The diagnosis and treatment of distal tibiofibular syndesmosis (DTFS) injury can be challenging, especially in cases of subtle instability that may be masked on 2-dimensional conventional radiographs. Weightbearing computed tomography (WBCT) has recently emerged as a useful diagnostic tool allowing direct assessment of distal tibiofibular area widening. The purpose of the current study was to examine and report normal threshold values for DTFS area measurements in a cohort of healthy volunteers, assessing the ankles in natural weightbearing position and under subject-driven external rotation stress.

METHODS

In this prospective study, we enrolled 25 healthy volunteers without a history of DTFS injury or high ankle sprain, previous foot and ankle surgery, or current ankle pain. Subjects with any prior ankle injuries were excluded. Study participants underwent bilateral standing nonstress and external rotation stress WBCT scans. The DTFS area (mm2) was semiautomatically quantified on axial-plane WBCT images 1 cm proximal to the apex of the talar dome using validated software. Syndesmosis area values were compared between "unstressed" and "stressed" ankles, as well as left and right ankles. Statistical analysis was performed using independent t tests/Wilcoxon analysis with statistical significance defined as P <.05.

RESULTS

The study cohort consisted of 50 ankles in 25 patients (12 males, 48%) with a mean age of 28.7 ± 9.3 years. In the unstressed ankle, the mean pooled DTFS area was determined to be 103.8 + 20.8 mm2. The mean syndesmosis area of unstressed left ankles (104.2 + 19.5 mm2) was similar to unstressed right ankles (109.2 + 17.2 mm2) in the cohort (P = .117). With external rotation stress, the DTFS area of left ankles (mean difference -0.304 mm2, CI -12.1 to 11.5; P = .082), right ankles (mean difference -5.5 mm2, CI 16.7-5.7; P = .132), and all ankles (mean difference -2.9 mm2, CI -10.8 to 5.1; P = .324) remained similar.

CONCLUSION

This study presents normal values and range for DTFS area calculation. In uninjured ankles with expected intact ligaments, subject-driven external rotation stress did not result in significant widening of the DTFS space as imaged on with WBCT.

LEVEL OF EVIDENCE

Level II, cross-sectional study.

Normal Distal Tibiofibular Syndesmosis Assessment Using Postmortem Computed Tomography (PMCT)

BACKGROUND

Distal tibiofibular syndesmotic injuries, often misdiagnosed, can lead to substantial morbidity. This study utilized postmortem computed tomography (PMCT) to define normal syndesmotic relationships in 131 subjects.

METHODS

Three parameters were measured: fibular rotation (FR), sagittal translation (ST), and incisura depth (ID).

RESULTS

Interobserver reliability was excellent for FR and ID but moderate for ST. Anatomical variability was wide, with FR ranging from -0.4° to 16.6°, ST from 0.33 mm to 3.49 mm, and ID from 1.89 mm to 6.05 mm. Side-to-side variability within subjects was minimal. Gender-specific differences were observed in ST, possibly due to size variations, highlighting the need for gender-specific diagnostic criteria.

CONCLUSIONS

Although establishing universal reference values is challenging, using contralateral ankles for comparison can enhance diagnostic accuracy in syndesmotic injuries. This study, the first of its kind, offers valuable insights into normal distal tibiofibular syndesmotic relationships based on PMCT data. Future validation studies in patients with syndesmotic injuries can further improve diagnostic accuracy.

Isolated Capitulum-Trapezoid Coalition: An Unusual Cause of Wrist Pain

Chronic wrist pain presents a diagnostic challenge, demanding a comprehensive understanding of its multifactorial etiology. This case report focuses on wrist coalition, an infrequent orthopedic condition characterized by abnormal articulations between carpal bones, often associated with prolonged wrist discomfort. A 45-year-old man with a two-year history of persistent left wrist pain, with no previous history of trauma or systemic illness, had a localized tenderness in the left carpal region with a restricted range of motion, and diminished grip strength on physical examination. Initial investigations, including autoimmune profiles and plain radiographs, were inconclusive. Magnetic resonance imaging ultimately identified a coalition between the capitulum and the trapezoid. A multidisciplinary team recommended a conservative approach, resulting in a positive response and symptomatic improvement during follow-up. This case report contributes valuable insights to the limited literature on isolated capitulum and trapezoid coalition, highlighting the significance of considering such rare orthopedic entities in the comprehensive evaluation of chronic wrist pain.

Safe Insertion Angle of the Suture Button to Avoid Saphenous Structure in Syndesmosis Injury

In placing the medial suture button for syndesmosis injury, the risk of great saphenous vein and saphenous nerve injury has been reported. This study aimed to determine the safe insertion angle of the guide pin to avoid saphenous structure injury during suture button fixation. The incidence of saphenous structure injury was investigated using 8 legs of cadavers. The greater saphenous vein was depicted on the skin using near-infrared light (VeinViewer® Flex) and the distance between the greater saphenous vein and the posterior edge of the tibia at levels of 10, 20, and 30 mm from the joint line of the tibiotalar joint was measured in the 60 legs of healthy participants. On computed tomography (CT) images, the angles between the greater saphenous vein and transmalleolar axis at levels of 10, 20, and 30 mm from the joint line of the tibiotalar joint were measured. The cadaveric study revealed that the percentages of contact with the saphenous nerve were 8.3% to 16.7%. Using near-infrared light, the vein and tibia distance was 32.9 ± 6.8 mm of 10 mm, 26.6 ± 6.4 mm of 20 mm, and 20.4 ± 6.4 mm of 30 mm. The angle between the vein and transmalleolar axis was 1.0° to 9.4°, and more proximal, the angle was smaller. The veins depicted by near-infrared light can be a landmark to identify great saphenous vein, and injury of the saphenous structure can be prevented using VeinViewer Flex or considering the insertion angle defined in this study when placing the suture button for syndesmosis injuries.Level of Evidence: Level IV.

Do lateral ankle ligaments contribute to syndesmotic stability: a finite element analysis study

Whether the lateral ankle ligaments contribute to syndesmotic stability is still controversial and has been the subject of frequent research recently. In our study, we tried to elucidate this situation using the finite element analysis method. Intact model and thirteen different injury models were created to simulate injuries of the lateral ankle ligaments (ATFL, CFL, PTFL), injuries of the syndesmotic ligaments (AITFL, IOL, PITFL) and their combined injuries. The models were compared in terms of LFT, PFT and EFR. It was observed that 0.537 mm LFT, 0.626 mm PFT and 1.25° EFR occurred in the intact model (M#1), 0.539 mm LFT, 0.761 mm PFT and 2.31° EFR occurred in the isolated ATFL injury (M#2), 0.547 mm LFT, 0.791 mm PFT and 2.50° EFR occurred in the isolated AITFL injury (M#8). The LFT, PFT and EFR amounts were higher in the both M#2 and M#8 compared to the M#1. LFT, PFT and EFR amounts in M#2 and M#8 were found to be extremely close. In terms of LFT and PFT, when we compare models with (LFT: 0.650 mm, PFT: 1.104) and without (LFT: 0.457 mm, PFT: 1.150) IOL injury, it is seen that the amount of LFT increases and the amount of PFT decreases with IOL injury. We also observed that injuries to the CFL, PTFL and PITFL did not cause significant changes in fibular translations and PFT and EFR values show an almost linear correlation. Our results suggest that ATFL injury plays a crucial role in syndesmotic stability.

Cortices of Fibula and Tibia Can Provide Landmarks for Accurate Syndesmosis Fixation Angle: Computed Tomography Validation of Angle Bisector Method

Anatomic syndesmosis reduction is necessary to restore ankle biomechanics and prevent poor clinical outcomes, but malreduction can be encountered frequently since the ideal fixation angle varies between patients and fixation levels. This study aimed to validate the angle bisector method to reveal whether it provides an accurate syndesmotic fixation angle that is patient- and level-specific. Lower extremity CT angiography of 50 consecutive patients (25 male, 25 female) without evident ankle pathology were evaluated. The average age was 52.8 (±18, range: 18-75). Lines tangent to anterior and posterior cortices of tibia and fibula were drawn in the axial plane at both 2 cm and 3.5 cm above the ankle joint line. Bisection of the angle formed between these lines was drawn and its relationship with the centroidal axis, which is proposed to be the ideal syndesmotic axis, was evaluated. The angle between the bisector line & the centroidal axis and the distance between their most lateral intersections with the fibula were calculated. The measurements were made by 3 blinded observers. Intra- and interobserver reliability analyses were conducted. The average centroidal axis-bisector angle was 2.1° ± 2.1° at 2 cm and 0.6° ± 1.3° at 3.5 cm level. The average distance to the actual syndesmosis entry point was 1.0 ± 0.9 mm at 2 cm and 0.4 ± 0.4 mm at 3.5 cm level. The values didn't show any significant difference according to gender. Intra- and interobserver reliability analysis showed excellent correlation in all parameters (interclass correlation coefficient > 0.90). Angle bisector method was found strongly reliable providing accurate direction for syndesmotic axis. It can provide a patient- and level-specific angle for the application of syndesmotic implants without increasing the fluoroscopy exposure. Its use can have a broad impact on functional outcomes of ankle injuries by decreasing the malreduction rates. Further cadaveric validation and safety studies should be conducted for possible clinical usage.

A Novel Flexible Fixation Method for Syndesmotic Injury

BACKGROUND

This study aims to evaluate the results and the safety of a novel fixation method we developed for syndesmosis injuries that we call the "embrace" technique.

METHODS

Between March 2018 and October 2020, a total of 67 patients with ankle fractures and syndesmotic injuries underwent syndesmosis fixation with the embrace technique at our institute. Plain radiographs and computed tomographic (CT) scans were obtained preoperatively. Postoperative radiographic assessment included anteroposterior (AP) and lateral radiographs and CT scans of both ankles. Additionally, the American Orthopaedic Foot & Ankle Society (AOFAS) Ankle-Hindfoot Score, Olerud-Molander Ankle Score, and visual analog scale (VAS) score were used for postoperative assessment.

RESULTS

The mean age was 27.6 ± 10.9 (range, 14-56) years. The mean follow-up time was 30.3 ± 6.2 (range, 24-48) months. There were no malreductions indicated by any CT parameter except fibular rotation in a postoperative comparison between 2 sides. We found significant preoperative-postoperative changes in anterior difference, posterior difference, and fibular rotation but no significant preoperative-postoperative difference in fibular translation. There was no significant postoperative difference between the affected-side and normal-side measurements of any parameter. Complications included delayed wound healing, lateral pain because of wire knot irritation (11.9%), and medial fiber wire irritation (7.5%). The mean AOFAS, Olerud-Molander, and VAS scores at the last follow-up were 94.4 ± 6.8 (range, 84-100), 95.4 ± 6.1 (range, 80-100), and 0.68 ± 1.0 (range, 0-3) points, respectively.

CONCLUSION

In our cohort, this novel technique proved to be an effective method for syndesmosis fixation in patients with ankle fractures associated with very good radiologic and patient-reported outcomes.

LEVEL OF EVIDENCE

Level IV, case series.

Physiologic Motion in the Intact and Unstable Syndesmosis During Plantigrade Weightbearing in Controlled Ankle Motion Boots

Consensus has not been reached for the optimal postoperative care after high ankle sprain and syndesmotic fixation. A potential drawback of earlier return to activity is greater instability of the ankle and fixation failure. The controlled ankle motion (CAM) boot has been an effective implementation to stabilize the leg and may aid in safe early weightbearing status. However, there is insufficient study of its effect on motion in the syndesmosis following injury. Hence, the aim of this cadaveric study was to determine the stability of the ankle with a CAM boot at 3 levels of injury: syndesmosis ligaments intact (no injury), syndesmosis ligaments cut, and syndesmosis and fibula cut. Six cadaveric legs were subjected to each level of injury and axially loaded at 1 Hz between 100 N-1.5 times body weight for 50 seconds, and axial force, axial displacement, and optical tracking data were recorded. It was found that the ankle, when protected by the CAM boot, maintained syndesmosis motion with no difference (p > .05) from the uninjured state, regardless of syndesmotic ligament and fibular injury. This finding was consistent across anterior-posterior, medial-lateral, and superior-inferior axes. Overall, our study may suggest that early weightbearing with a CAM boot maintains a physiologically range of motion in the syndesmosis.

Anterior Incisura Fibularis Corner Landmarks Can Safely Validate the Optimal Distal Tibiofibular Reduction in Malleolar Fractures-Prospective CT Study

BACKGROUND

Distal tibiofibular injuries are common in patients with malleolar fractures. Malreduction is frequently reported in the literature and is mainly caused by insufficient intraoperative radiological evaluation. In this direction, we performed a prospective observational study to validate the efficacy of the anatomical landmarks of the anterior incisura corner.

METHODS

Patients with malleolar fractures and syndesmotic instability were reduced according to specific anatomic landmarks and had a postoperative bilateral ankle CT. The quality of the reduction was compared to the healthy ankles.

RESULTS

None of the controlled parameters differed significantly between the operated and healthy ankles. Minor deviations were correlated to the normal incisura morphology rather than the reduction technique.

CONCLUSIONS

The anterior incisura anatomical landmarks can be an efficient way of reducing the distal tibiofibular joint without the need for intraoperative radiological evaluation.

Factors and Radiographic Findings Influencing Patient-Reported Outcomes Following Maisonneuve Fractures

BACKGROUND

This research adds to the literature by providing prognostic information for physicians and patients regarding the outcomes of operative management of Maisonneuve fractures (MFs). To date, this is the only cohort study of patient-reported outcomes measurement information systems (PROMIS) scores following surgical fixation of MF. Patient outcomes were compared focusing on the mean population with an inter-analysis using basic demographic information, radiographic findings, and patient comorbidities and their respective impact on PROMIS scores.

METHODS

A total of 24 patients between 2012 and 2020 met the inclusion criteria and completed PROMIS surveys at a minimum of 18 months postoperatively. Patient charts were reviewed through the electronic medical record (EMR) for demographic information and comorbidities as well as operative variables. PROMIS scores for physical function (PF), pain interference (PI), and depression were obtained via follow-up visits and phone calls. The impact of categorical variables on complications was compared using Chi-Squared tests. Variables were analyzed with a type 3 SS test to stratify independent risk factors' effect on PROMIS scores and to account for confounding variables.

RESULTS

PROMIS PF averaged 44.84 and was significantly affected by BMI>30 (p=.033), hypertension (HTN) (p=.026), patients with clinical anxiety or depression (p=.047), and subsequent screw removal (p=.041). PROMIS PI averaged a score of 54.57 and was significantly affected by BMI>30 (p=.0046), coronary artery disease (CAD) (p=.0123), patients with clinical anxiety or depression (p=.0206), and subsequent screw removal (p=.0039). PROMIS depression scores averaged 46.03 and were significantly affected by the presence of CAD (p=.049) and subsequent screw removal (p=.023).

CONCLUSION

Patient-reported outcomes following MF surgery demonstrated PROMIS scores within +/- 1 standard deviation of the population-based control, and thus many patients can reasonably expect to return to a level of function comparable to the general population. Nonetheless, the significant effects of patient comorbidities and surgical variables ought to be evaluated and utilized as prognostic indicators when managing patient expectations prior to operative treatment of an MF injury.

Objective Assessment of Syndesmosis Stability Using the Hook Test

The hook test is a widely used intraoperative method for assessing syndesmosis stability. However, there are no recommendations regarding the force required to perform this test. Furthermore, the reliability of the test is unclear. Ten experienced surgeons performed hook tests on a cadaver bone model. The applied forces were recorded in a blinded manner. In addition, standardized hook tests with defined forces (50, 80, and 100 N) were performed on 10 pairs of cadaver lower legs and the syndesmosis was sequentially destabilized. Diastasis of the syndesmosis was recorded using an optical 3D camera system. A median force of 81 N (Range: 50 N-145 N) was applied. A proportion of 82% of the tests showed a force < 100 N. The data showed good intraraterreliability and poor interraterreliability. In the standardized investigation of the hook test on the cadaver bone model, both the force and the instability of the syndesmosis had a significant influence on the syndesmosis diastasis. Nevertheless, even with maximum instability of the syndesmosis, diastasis > 2 mm could only be measured in 12 of the 19 evaluable specimens. The widely used hook test shows a high variability when performed in practice. Even in a standardized manner, the hook test cannot detect a relevant syndesmosis injury.

Predictors of Hardware Removal in Orthopaedic Trauma Patients Undergoing Syndesmotic Ankle Fixation With Screws

Background

Indications for removal of syndesmotic screws are not fully elucidated. This study aimed to determine factors related to elective syndesmotic screw removal.

Methods

Patients who underwent fixation of ankle syndesmotic injuries were included. Screw removal was offered after a minimum of 12 weeks after surgery for pain, stiffness or patient desire to remove painful or broken hardware. Patient demographics, surgical data, distance of the syndesmotic screw from the joint, location of the screw at the physeal scar, and number of syndesmotic screws placed were collected for all patients. Bivariate and multivariate analyses were performed to determine the relationship between patient characteristics and screw removal and independent predictors of hardware removal.

Results

Of 160 patients, 60 patients (38%) with an average age of 36.1 (range: 18-84) years underwent elective syndesmotic screw removal at a mean of 7 (range, 3-47) months after initial fixation. The most common reason for screw removal (50/60 patients) was ankle stiffness and pain (83%). Patients who underwent screw removal were more likely to be younger (36.1 years ± 13.0 vs 46.6 years ± 18.2, P < .001) and have a lower ASA score (2 ± 0.8 vs 2.1 ± 0.7, P = .003) by bivariate analysis. Of patients who underwent screw removal, 21.7% (13/60) had a broken screw at the time of removal. Whether the screw was placed at the physeal scar was not significantly associated with patient decision for hardware removal (P = .80).

Conclusion

Younger and healthier patients were more likely to undergo elective removal of syndesmotic hardware. Screw distance from joint and screw placement at the physeal scar were not significantly associated with hardware removal.

Level of Evidence

Level III, retrospective cohort study.

Syndesmotic Suture Button Fixation Results in Higher Tegner Activity Scale Scores When Compared to Screw Fixation: A Multicenter Investigation

BACKGROUND

Suture buttons and metal screws have been used and compared in biomechanical, radiographic, and clinical outcome studies for syndesmotic injuries, with neither implant demonstrating clear superiority. The aim of this study was to compare clinical outcomes of both implants.

METHODS

Patients who underwent syndesmosis fixation at 2 separate academic centers from 2010 through 2017 were compared. Thirty-one patients treated with a suture button and 21 patients treated with screws were included. Patients in each group were matched by age, sex, and Orthopaedic Trauma Association fracture classification. Tegner Activity Scale (TAS), Foot and Ankle Ability Measure (FAAM), patient satisfaction score, surgical failure, and reoperation rates were compared.

RESULTS

Patients who underwent suture button fixation had significantly higher TAS scores than those who underwent screw fixation (p < 0.001). There was no significant difference in FAAM ADL scores between cohorts (p = 0.08). Symptomatic hardware removal rates were similar (3.2% suture button cohort vs 9.0% in screw cohort). One patient (4.5%) underwent revision surgery secondary to syndesmotic malreduction after screw fixation, for a reoperation rate of 13.5%.

CONCLUSION

Patients with unstable syndesmotic injuries treated with suture button fixation had higher mean TAS scores compared to patients treated with screws. Foot and Ankle Ability Measure and ADL scores in these cohorts were similar.Level of Evidence: Level 3 Retrospective Matched Case-Cohort.

Instability of the distal tibiofibular syndesmosis

The distal tibiofibular syndesmosis (DTFS) is more frequently injured than previously thought. Early diagnosis and appropriate treatment is essential to avoid long term complications like chronic instability, early osteoarthritis and residual pain. Management of these injuries require a complete understanding of the anatomy of DTFS, and the role played by the ligaments stabilizing the DTFS and ankle. High index of suspicion, appreciating the areas of focal tenderness and utilizing the provocative maneuvers help in early diagnosis. In pure ligamentous injuries radiographs with stress of weight bearing help to detect subtle instability. If these images are inconclusive, then further imaging with MRI, CT scan, stress examination under anesthesia, and arthroscopic examination facilitate diagnosis. An injury to syndesmosis frequently accompanies rotational fractures and all ankle fractures need to be stressed intra-operatively under fluoroscopy after fixation of the osseous components to detect syndesmotic instability. Non-operative treatment is appropriate for stable injuries. Unstable injuries should be treated operatively. Anatomic reduction of the syndesmosis is critical, and currently both trans-syndesmotic screws and suture button fixation are commonly used for syndesmotic stabilization. Chronic syndesmotic instability (CSI) requires debridement of syndesmosis, restoration of ankle mortise with or without syndesmotic stabilization. Arthrodesis of ankle is used a last resort in the presence of significant ankle arthritis. This article reviews anatomy and biomechanics of the syndesmosis, the mechanism of pure ligamentous injury and injury associated with ankle fractures, clinical, radiological and arthroscopic diagnosis and surgical treatment.

Effect of Arthroscopically Confirmed Syndesmotic Widening on Outcome Following Isolated Broström Operation for Chronic Lateral Ankle Instability

BACKGROUND

Tibiofibular syndesmosis (TFS) widening sometimes is not evident on radiography but can be found under arthroscopy in chronic lateral ankle instability (CLAI). This study aimed to evaluate the effect of TFS widening severity on clinical outcomes and return to activities after isolated Broström operation in CLAI patients and to propose an indication for its surgical intervention.

METHODS

A total of 118 CLAI patients undergoing diagnostic ankle arthroscopy and open Broström-Gould operation were included. Based on the middle width of TFS measured under arthroscopy, patients were divided into the TFS-2 group (≤2 mm, n = 44), the TFS-3 group (2-4 mm, n = 42), and the TFS-4 group (≥4 mm, n = 32). The time to return to recreational sport and work, Tegner activity score, and proportion of returning to preinjury sports at the final follow-up were evaluated and compared. Other subjective evaluations included the American Orthopaedic Foot & Ankle Society score, visual analog scale, and Karlsson-Peterson score.

RESULTS

Among the 3 groups, the TFS-4 group demonstrated the longest mean time to return to work and recreational sports, with the lowest proportion returning to preinjury sports. The TFS-4 group showed a significantly higher rate of sprain recurrence (12.5%) than the other 2 groups (P =.021). All the other subjective scores significantly improved after the operation without differences among the 3 groups.

CONCLUSION

Concomitant severe syndesmotic widening adversely affects the return to activities after Broström operation in CLAI cases. The CLAI patients with a middle TFS width ≥4 mm were associated with delayed return to work and sports, a lower proportion of returning to preinjury sports, and more sprain recurrence, which might require further surgical intervention for syndesmosis in addition to Broström surgery.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Diagnostic Accuracy of Conventional Ankle CT Scan With External Rotation and Dorsiflexion in Patients With Acute Isolated Syndesmotic Instability

BACKGROUND

Syndesmotic injury in an athletic population is associated with a prolonged ankle disability after an ankle sprain and often requires a longer recovery than a lateral collateral ligament injury. Although several imaging tests are available, diagnosing syndesmotic instability remains challenging.

PURPOSE

To determine the diagnostic accuracy of conventional ankle computed tomography (CT) scans with the joint in external rotation and dorsiflexion and compare it with that of conventional ankle CT scans in a neutral position.

STUDY DESIGN

Cohort study (Diagnosis); Level of evidence, 2.

METHODS

Between September 2018 and April 2021, this prospective study consecutively included adults visiting the foot and ankle outpatient clinic with a positive orthopaedic examination for acute syndesmotic injury. Participants underwent 3 CT scan tests. First, ankles were scanned in a neutral position. Second, ankles were scanned with 45° of external rotation, dorsiflexion, and extended knees. Third, ankles were scanned with 45° of external rotation, dorsiflexion, and flexed knees. Three measurements, comprising rotation (measurement a), lateral translation (measurement c), and anteroposterior translation (measurement f) of the fibula concerning the tibia, were used to diagnose syndesmotic instability in the 3 CT scans. Magnetic resonance imaging was used as a reference standard. The area under the curve (AUC) was used to compare the diagnostic accuracy, and Youden's J index was calculated to determine the ideal cutoff point.

RESULTS

Images obtained in 68 participants (mean age, 36.5 years; range, 18-69 years) were analyzed, comprising 36 syndesmotic injuries and 32 lateral collateral ligament injuries. The best diagnostic accuracy occurred with the rotational measurement a, in which the second and third CT scans with stress maneuvers presented greater AUCs (0.97 and 0.99) than did the first CT scan in a neutral position (0.62). The ideal cutoff point for the stress maneuvers was 1.0 mm in the rotational measurement a and reached a sensitivity and specificity of 83% and 97% for the second CT scan with extended knees and 86% and 100% for the third CT scan with flexed knees, respectively. The ideal cutoff point for the first CT scan with a neutral position was 0.7 mm in the rotational measurement a, with a sensitivity of 25% and specificity of 97%.

CONCLUSION

Conventional ankle CT with stress maneuvers has excellent performance for diagnosing subtle syndesmotic rotational instability, as it shows a greater AUC and enhanced sensitivity at the ideal cutoff point compared with ankle CT in the neutral position.

Diagnostic Value of DECT-Based Collagen Mapping for Assessing the Distal Tibiofibular Syndesmosis in Patients with Acute Trauma

Background: Injury to the distal tibiofibular syndesmosis (DTFS) is common in patients with trauma to the ankle, but diagnostic accuracy of conventional X-ray and CT is insufficient. A novel dual energy CT (DECT) post-processing algorithm enables color-coded mapping of collagenous structures, which can be utilized to assess the integrity of the DTFS. Methods: Patients were included in this retrospective study if they underwent third-generation dual-source DECT followed by 3T-MRI or ankle joint surgery within 14 days between January 2016 and December 2021. Three radiologists blinded to all patient data independently evaluated grayscale images and, after 8 weeks, grayscale and collagen mapping images for the presence of ligamentous injury or avulsion fractures of the DTFS. MRI and surgery provided the reference standard. Diagnostic accuracy parameters were calculated for all ratings, and a comparison of ROC curve analysis was performed to evaluate the incremental diagnostic value of color-coded images over grayscale images. Results: A total of 49 patients (median age 49 years; 32 males) were evaluated. Application of collagen mapping significantly increased sensitivity (25/30 [83%] vs. 20/30 [67%]), specificity (110/118 [93%] vs. 70/118 [60%]), positive predictive value (25/33 [76%] vs. 20/67 [30%]), negative predictive value (110/115 [96%] vs. 70/80 [88%]), and accuracy (134/147 [91%] vs. 90/147 [61%]) for the detection of injury to the DTFS (all parameters, p < 0.001). Collagen mapping achieved higher diagnostic confidence, image quality, and noise scores compared to grayscale CT (all parameters, p < 0.001). Conclusions: Collagen mapping yields substantially higher diagnostic accuracy and confidence for assessing the integrity of the distal tibiofibular syndesmosis compared to grayscale CT in patients with acute trauma. The application of this algorithm can accelerate the adequate diagnosis and treatment of DTFS injury in clinical routine.

Fibula Nail versus Locking Plate Fixation-A Biomechanical Study

In the treatment of ankle fractures, complications such as wound healing problems following open reduction and internal fixation are a major problem. An innovative alternative to this procedure offers a more minimally invasive nail stabilization. The purpose of this biomechanical study was to clarify whether this method was biomechanically comparable to the established method. First, the stability (range of motion, diastasis) and rotational stiffness of the native upper ankle were evaluated in eight pairs of native geriatric specimens. Subsequently, an unstable ankle fracture was created and fixed with a locking plate or a nail in a pairwise manner. The ankles showed significantly less stability and rotational stiffness properties after nail and plate fixations than the corresponding native ankles (p < 0.001 for all parameters). When comparing the two methods, both showed no differences in their range of motion (p = 0.694) and diastasis (p = 0.166). The nail also presented significantly greater rotational stiffness compared to the plate (p = 0.001). However, both fixations remained behind the native stability and rotational stiffness. Due to the comparable biomechanical properties of the nail and plate fixations, an early weight-bearing following nail fixation should be assessed on a case-by-case basis considering the severity of fractures.

Value of Intraoperative 3D Imaging on the Quality of Reduction of the Distal Tibiofibular Joint When Using a Suture-Button System

BACKGROUND

The quality of reduction of the distal tibiofibular joint (DTFJ) has a major impact on the outcome. Novel suture-button systems as well as intraoperative 3D imaging can be applied to increase the quality of DTFJ reduction intraoperatively. The individual effect of either remains unknown. The aim of this study was to investigate the value of intraoperative 3D imaging on the quality of reduction of the DTFJ when using a suture-button system.

METHODS

Retrospective, radiographic study including adult patients who underwent surgical stabilization of the syndesmosis with a suture-button system for acute, unilateral, unstable syndesmotic injuries with postoperative bilateral CT imaging. The use of an intraoperative 3D scan was the individual surgeon's choice. Assessed was whether the intraoperative 3D imaging had an influence on the postoperative quality of DTFJ reduction and revision rates. These findings were put in perspective to the correction potential of the suture-button system.

RESULTS

A total of 147 patients were included; 76 of these received an intraoperative 3D imaging. Neither the rate of formal malreduction (17% vs 17%) nor the postoperative revision rate (4% vs 3%) differed significantly between patients with or without intraoperative 3D imaging. Intraoperative 3D imaging revealed a false-negative rate of 14%. The intrinsic correction potential of the suture-button system reduced the number of formally malreduced DTFJs in both groups by 51%.

CONCLUSION

The additional value of intraoperative 3D imaging to assess the quality of DTFJ reduction in our series did not improve syndesmotic reduction when using a flexible suture-button system.

LEVEL OF EVIDENCE

Level III, retrospective comparative cohort study.

Use of a Lightweight Portable Fluoroscopy Device for Obtaining Weightbearing Ankle Images

Portable fluoroscopy devices provide point-of-care imaging in emergency and out-patient clinics. In this prospective study, we compared weightbearing images of syndesmosis obtained using a novel lightweight portable battery-powered fluoroscopy device with those obtained with a conventional radiography device. Eleven healthy participants underwent bilateral 3-view weightbearing imaging of both ankles using a radiography (X-ray group) device and a portable fluoroscopy system (LPF group). Anteroposterior, mortise, and lateral views were compared between the 2 techniques. Radiographic measurements were done by 2 observers. These measurements included talar tilt, tibiofibular clear space, tibiofibular overlap, plafond malleolar angle, medial distal tibial angle, medial clear space, lateral distal tibial angle, anterior and posterior tibiofibular distance were measured using the appropriate view. Data were compared between the 2 techniques; the interobserver agreement was calculated within each group. P < .05 was considered statistically significant. Comparing the 2 imaging modalities, there was no significant difference between the measurements in LPF and X-ray groups except plafond malleolar angle. The overall interobserver agreement was excellent between the 2 observers. There was no significant difference between the measures by the 2 observers and between the bilateral ankles. Fluoroscopy was associated with about 50% extra radiation exposure, although the absolute amount of radiation was not clinically significant. These results support the use of weightbearing images using portable fluoroscopy device as an alternative for the conventional radiography systems.

Biomechanical Analysis of Tibiofibular Syndesmosis Injury Fixation Methods: A Finite Element Analysis

The optimal treatment strategy after syndesmotic injuries is still controversial. In our study, we aimed to evaluate ideal fixation method in syndesmotic injury by using finite element analysis method. A 3D SolidWorks model file was created by taking computed tomography (CT) images of the area from the right foot base to the knee joint level of a healthy adult male. The intact model, injury model, and 8 different fixation models were created that 3.5 mm screw and suture-button were used in. The models were compared in terms of lateral fibular translation, posterior fibular translation and external rotation of fibula compared to tibia and stress values occurred on screws and suture-buttons. In the hybrid-1 model, lateral fibular translation and external fibular rotation values were obtained as close to the intact model. Von Mises stresses occurred in the screw (435.7 MPa) and suture-button (424.7 MPa) that used in hybrid-1 model was more than single screw at 4 cm model (316.8 MPa) and single suture-button at 2 cm model (160.7 MPa). In the Hybrid-1 model, the screw compensates for posterior fibular translation and external fibular rotation, while the suture-button compensates for lateral fibular translation. Also, the effect of the distal suture-button preventing diastasis in case of proximal screw failure, it was concluded that the hybrid-1 model can be used as a good treatment alternative in the surgical treatment of distal tibiofibular syndesmotic injuries.

Management of Syndesmosis Injury: A Narrative Review

The syndesmosis is an important fibrous joint that plays a crucial role in normal ankle weight-bearing and movements. Syndesmosis injuries include disruption of one or more of the ligaments comprising the distal tibiofibular syndesmosis and are commonly associated with ankle fractures. The treatment of grade 1 syndesmosis injury should be conservative, such as immobilization for one to three weeks followed by gradual return to activity. For the treatment of grade 2 syndesmosis injury, if it was stable enough, the patients still could be managed with conservative therapies. But majority of them strongly favor surgical treatment. For the treatment of grade 3 syndesmosis injury, it should treat with surgical reconstruction. If syndesmosis injury is associated with ankle fractures, surgical reduction, fixation, and reconstruction are usually required. Common surgical treatment methods include syndesmosis screws, composed of either metallic or bioabsorbable material; fibula intramedullary nails; and dynamic button-suture fixation, TightRope or ZipTight. Each method has advantages and disadvantages which must be considered while determining which treatment will provide the best outcomes depending on the patient's needs. Continued exploration of new materials, devices, and methods for surgical fixation is necessary for advancement in this field.

Restoration of Anatomic Parameters and Syndesmotic Reduction After Intramedullary Nailing of Distal Fibular Fractures

Background:

Intramedullary nailing of the fibula (FN) is a method of fixation that has proven to be useful for treating distal fibular fractures (DFs). FN minimizes soft tissue complications and provides similar stability to plating, with fewer hardware-related symptoms. Nevertheless, FN has been associated with syndesmotic malreduction and the incapacity of restoring length and rotation of the fibula. We aimed to evaluate the fibular position and syndesmotic reduction after fixation with FN compared with the uninjured ankle in the immediate postoperative period.

Methods:

Prospective cohort study. Patients with DF fractures treated with IN between January 2017 and January 2020 were included. Immediate postoperative bilateral ankle CT was obtained in all cases. Fibular rotation, length, and translation as well as syndesmotic diastasis were measured on both ankles and compared by 3 independent observers.

Results:

Twenty-eight patients were included (16 women). The mean age was 46 years (range 16-91). Fracture type distribution according to AO/ASIF classification included 19 patients with 44.B (67.9%), 8 patients with 44.C (28.6%), and 1 patient with a 44.A fracture (3.6%). No significant differences were identified considering fibular rotation (P = .661), syndesmotic diastasis (P = .147), and fibular length (P = .115) between the injured and uninjured ankle. Fibular translation had statistical differences (P = .01) compared with the uninjured ankle. The intraclass correlation coefficient showed an excellent concordance between observers except for fibular translation on the injured ankle.

Conclusion:

In this cohort, fixation of DF fractures with FN allows restoration of anatomical parameters of the ankle in terms of fibular rotation, length, and syndesmotic diastasis. However, fibular translation had significant differences compared with the uninjured ankle based on bilateral CT scan evaluation.

Level of Evidence:

Level II, prospective cohort study.

Fluoroscopic Evaluation of the Role of Syndesmotic Injury in Lateral Ankle Instability in a Cadaver Model

BACKGROUND

There is a high prevalence of concomitant lateral ankle ligament injuries and syndesmotic ligamentous injuries. However, it is unclear whether syndesmotic ligaments directly contribute toward the stability of the lateral ankle. Therefore, the aim of this study was to fluoroscopically evaluate the role of the syndesmotic ligaments in stabilizing the lateral ankle.

METHODS

Twenty-four cadaveric specimens were divided into 3 groups and fluoroscopically evaluated for lateral ankle stability with all syndesmotic and ankle ligaments intact and then following serial differential ligamentous transection. Group 1: (1) anterior talofibular ligament (ATFL), (2) calcaneofibular ligament (CFL), and (3) posterior talofibular ligament (PTFL). Group 2: (1) anterior inferior tibiofibular ligament (AITFL), (2) interosseous ligament (IOL), (3) posterior inferior tibiofibular ligament (PITFL), (4) ATFL, (5) CFL, and (6) PTFL. Group 3: (1) AITFL, (2) ATFL, (3) CFL, (4) IOL, (5) PTFL, and (6) PITFL. At each transection state, 3 loading conditions were used: (1) anterior drawer test performed using 50 and 80 N of direct force, (2) talar tilt <1.7 Nm torque, and (2) lateral clear space (LCS) <1.7 Nm torque. These measurements were in turn compared with those of the stressed intact ligamentous state. Wilcoxon rank-sum test was used to compare the findings of each ligamentous transection state to the intact state. A P value <.05 was considered statistically significant.

RESULTS

The lateral ankle remained stable after transection of all syndesmotic ligaments (AITFL, IOL, PITFL). However, after additional transection of the ATFL, the lateral ankle became unstable in varus and anterior drawer testing conditions (P values ranging from .036 to .012). Lateral ankle instability was also observed after transection of the ATFL and AITFL in varus and anterior drawer testing conditions (P values ranging from .036 to .012). Subsequent transection of the CFL and PTFL worsened the lateral ankle instability.

CONCLUSION

Our findings suggest that isolated syndesmosis disruption does not result in lateral ankle instability. However, the lateral ankle became unstable when the syndesmosis was injured along with ATFL disruption.

CLINICAL RELEVANCE

When combined with ATFL release, disruption of the syndesmosis appeared to destabilize the lateral ankle.

Compensation of Dynamic Fixation Systems in the Quality of Reduction of Distal Tibiofibular Joint in Acute Syndesmotic Complex Injuries: A CT-Based Analysis

BACKGROUND

There is an ongoing discussion on how to best stabilize syndesmotic injuries. Previous studies have indicated a better quality of reduction of the distal tibiofibular joint (DTFJ) for the suture button systems compared to syndesmotic screw fixation. Still, the reason for this superiority remains unclear. The aims of this retrospective study were to (1) analyze the deviation of the tibial and fibular drilling tunnels of the suture button system and (2) to compare these to the quality of reduction of the DTFJ assessed on bilateral postoperative CT images.

METHODS

Included were all adult patients who underwent syndesmotic stabilization for an acute injury using a suture button system, with postoperative, bilateral CT imaging over a 10-year period. A total of 147 patients were eligible. Based on individually reconstructed axial CT slices, the postoperative quality of reduction of the DTFJs was rated on bilateral CT images. Furthermore, the rotation and translation of the suture button drilling tunnels were analyzed. Based on these measurements, the intraoperative reduction of the DTFJ was recalculated and again rated. Using these values, the correction potential of suture button systems on the reduction of the DTFJ was analyzed.

RESULTS

(1) The drilling tunnel deviated considerably for both rotation |2.3±2.1 degrees| (range: |0.0-13.1 degrees|) and translation |0.9±0.8 mm| (range: |0-4.3 mm|). Based on the deviation of the drilling tunnels in fibula and tibia, the calculated intraoperative reduction of the DTFJ was classified as malreduced in 35.4%. (2) The DTFJ was postoperatively identified as malreduced in 17% of patients. Overall, the suture button system tended to compensate toward a more anatomical reduction both in the axial and sagittal plane.

CONCLUSION

A suture button system postoperatively deviates and apparently has the capacity to compensate for intraoperative malreduction. Analysis of the drilling tunnels revealed that the use of a rigid fixation system would have doubled the postoperative malreduction rate.

A systematic review and meta-analysis on the value of the external rotation stress test under fluoroscopy to detect syndesmotic injuries

Purpose

Methods

Results

Conclusion

Kirschner Wire as a Reference Marker for the Positioning of a Syndesmotic Screw: A Radiological Study and Clinical Evaluation

OBJECTIVE

No consensus has been reached regarding optimal implantation for a syndesmotic screw. Thus, we aimed to explore the feasibility of a reliable and static fibular incisura plane reference for ideal syndesmotic screw placement.

METHODS

A retrospective review of computed tomography (CT) scans of 42 uninjured adult ankles with foot fractures were analyzed to measure the tibiofibular vertical distance (TFVD) at 2.5 cm proximal to the plafond from August 2016 to June 2017 in our hospital. The patients (20 females, 22 males) were divided into four groups according to their TFVD: 0-1, 1-2, 2-3, and 3-4 mm, and patients in each group were counted. We retrospectively assessed 41 patients (15 females, 26 males) who underwent syndesmotic screw fixation for ankle fractures from December 2015 to June 2020. We performed t-testing of two independent samples to determine the differences in the angle between the anatomic axis of the syndesmosis and screw axis (AAS) and ankle function using the American Orthopaedic Foot and Ankle Society (AOFAS) score at 3 and 6 months postoperatively between the conventional (20 patients) and K-wire marker (21 patients) groups. The correlation between the AAS and AOFAS score was analyzed.

RESULTS

The TFVD measured 2.23 ± 1.01 mm at 2.5 cm proximal to the plafond, and occurred at 25% of the distance from 2 to 3 mm in 47.6% of the patients. This new technique decreased AAS deformation by 62%, from 13.01° ± 2.84° to 4.89° ± 2.43°, in the conventional group (p < 0.001). At 3 months postoperatively, the AOFAS scores of ankle function were similar in both groups, but it was significantly better in the new group than that of conventional group at the 6-month follow-up (p = 0.024). There was a moderate negative correlation between AAS and AOFAS score at 6 months postoperatively (R = -0.684). No obvious complications affecting ankle function were observed in either group postoperatively.

CONCLUSIONS

Surgeons can accurately place a screw trajectory using the fibular incisura plane as a reliable intraoperative reference. A 1.6-mm K-wire placed in the syndesmosis at 2.5 cm proximal to the tibial plafond could act as a static marker of the syndesmotic plane.

Anterior Inferior Tibiofibular Ligament Suture Tape Augmentation for Isolated Syndesmotic Injuries

BACKGROUND

The best operative construct and technique for treatment of isolated syndesmotic injuries is highly debated. The purpose of this study was to determine whether the addition of anterior inferior tibiofibular ligament (AITFL) suture repair or suture tape (ST) augmentation provides any biomechanical advantage to the operative repair of an isolated syndesmotic injury.

METHODS

Twelve lower leg specimens underwent biomechanical testing in 6 states: (1) intact, (2) AITFL suture repair, (3) AITFL suture repair + transsyndesmotic suture button (SB), (4) AITFL suture repair + ST augmentation + SB, (5) AITFL suture repair + ST augmentation, and (6) complete syndesmotic injury. The ankle joint was subjected to 6 cycles of 5 Nm internal and external rotation torque under a constant axial load. The spatial relationship between the tibia, fibula, and talus was continuously recorded with a 5-camera motion capture system.

RESULTS

AITFL suture repair and AITFL suture repair + ST augmentation showed no statistically significant change in fibula kinematics compared to the intact state. Compared to native, AITFL suture repair + SB showed increased fibular external rotation (+2.32 degrees, P < .001), and decreased tibiofibular gap (overtightening) (-0.72 mm, P = .007). AITFL suture repair + ST augmentation + SB also showed increased fibular external rotation (+1.46 degrees, P = .013). Sagittal plane motion of the fibula was not significantly different between any states. None of the repairs restored intact state talus rotation; however, the repairs that used ST augmentation reduced the talus external rotation laxity compared to the complete syndesmotic injury.

CONCLUSION

AITFL suture repair and AITFL ST augmentation best restored the rotational kinematics and stability of the fibula and ankle joint in an isolated syndesmotic injury model.

CLINICAL RELEVANCE

AITFL suture repair with or without ST augmentation may be a good operative addition or alternative to SB fixation for isolated syndesmotic disruptions.

Prospective Results of the Modified Glide Path Technique for Improved Syndesmotic Reduction During Ankle Fracture Fixation

BACKGROUND

Malreduction after syndesmotic stabilization occurs in as many as 52% of cases and has been shown to detrimentally affect clinical outcomes. We propose that the modified Glide Path technique reduces the occurrence of syndesmotic malreduction.

METHODS

This study is a prospective series comparing 16 patients reduced with the modified Glide Path technique with a retrospectively reviewed series of 25 patients reduced with a traditional technique using fluoroscopy and a clamp. The modified Glide Path technique consists of manual reduction of the fibula and placement of a Kirschner wire through the fibula and tibia along the transmalleolar axis. The syndesmosis can then be reduced along the glide path created by the Kirschner wire to prevent posterior or anterior malreduction. Computed tomographic scans of the repaired and contralateral ankles were obtained postoperatively to assess reduction.

RESULTS

We found a statistically significant decrease of syndesmotic malreductions using the modified Glide Path technique when compared with technique that did not use a glide path. In our study, 2 of 16 patients (12.5%) had syndesmotic malreductions using the modified Glide Path technique, compared with 11 of 25 patients (44%) with syndesmotic malreductions in the historical cohort.

CONCLUSION

The modified Glide Path technique is a simple method for ankle syndesmotic reduction. The technique has lower rates of malreduction compared with historical methods and may be useful for most operative syndesmotic injuries.

LEVEL OF EVIDENCE

Level II, prospective cohort study.

Bilateral ankle syndesmosis injury: a rare case report

This report describes a case of bilateral acute ankle syndesmosis injuries in a 15-year-old male basketball player. The patient had a background of previous inversion injuries but no symptoms of chronic pain or instability. The case report illustrates the importance of clinical suspicion when evaluating acute syndesmosis injuries in conjunction with radiographic assessments in primary care. This is the first reported case of such injury in bilateral limbs.

Investigating the Radiological Outcomes of Syndesmosis Injuries in Ankle Fracture Patients After Suture Button Fixation

Concomitant syndesmotic injury occurs in 10% of ankle fractures. Anatomic reduction and maintenance of this reduction is critical in ensuring ankle stability and preventing long-term complications. This is a retrospective cohort study aimed at evaluating the mid-term radiological outcomes of syndesmotic injuries in ankle fracture patients after surgical fixation with suture button device. The study group included 33 patients. Plain radiographs including anteroposterior, lateral and mortise views of the affected ankle were performed preoperatively, postoperatively and at 3-month follow-up. Anteroposterior views were used to measure the amount of tibiofibular overlap and tibiofibular clear space. Paired Student's t test and linear model regression were performed. Between the immediate postoperative and 3-month follow-up period, there was a mean decrease in tibiofibular overlap of 0.841 (±2.07) mm (p = .0259). There was a mean increase in tibiofibular clear space of 0.621 (±1.46) mm (p = .0201). In addition, we found significant correlation between fracture type and change in tibiofibular clear space (p = .047). Our study showed that there is statistically significant widening of the syndesmosis after suture button fixation at 3-month follow-up as evidenced by reduced tibiofibular overlap and increase in tibiofibular clear space. However, they remain within the maximum threshold for acceptable syndesmotic widening of 1.5 mm. Further correlation between radiological outcomes and patient function is needed to determine clinical significance of these changes.

Arthroscopic Quantitative Measurement of Medial Clear Space for Deltoid Injury of the Ankle: A Cadaveric Comparative Study With Stress Radiography

BACKGROUND

The deltoid ligament (DL) is an important stabilizer of the ankle. DL injury of varying severity can occur alone or with syndesmotic injury and fibular fracture. Limited diagnostic tools are available to assess DL injury quantitatively.

PURPOSE

To establish an arthroscopic quantitative assessment of DL injury and to compare its performance with that of external rotation stress (ERS) and gravity stress (GS) radiography.

STUDY DESIGN

Controlled laboratory study.

METHODS

In total, 24 cadaveric lower extremities were divided into 4 groups: group 1 consisted of intact DL, group 2 of superficial DL disruption, group 3 of deep DL disruption, and group 4 of complete DL (superficial and deep) disruption. All specimens underwent sequential sectioning of syndesmotic ligaments, and medial clear space (MCS) was measured with ankle arthroscopy, ERS radiography, and GS radiography at different stages of syndesmotic sectioning.

RESULTS

For noninjured deltoid (group 1) and injured deltoid (groups 2-4), area under the receiver operating characteristic curve (AUC) of measurement of MCS was 0.939 for arthroscopy, 0.932 for ERS radiography, and 0.874 for GS radiography, with a significant difference between arthroscopy and GS radiography (P = .014). For incomplete deltoid injury (groups 1-3) and complete deltoid injury (group 4), the AUC of MCS was 0.811 for arthroscopy, 0.656 for ERS radiography, and 0.721 for GS radiography, with a significant difference between arthroscopy and ERS radiography (P < .001) and between arthroscopy and GS radiography (P = .035). For all stages of syndesmotic sectioning, cutoff values of arthroscopic MCS with intact fibula were ≤2.5 mm for intact DL, between 2.5 and 3.5 mm for partial DL injury (superficial or deep), and ≥3.5 mm for complete DL injury. Arthroscopy was unable to detect a difference between superficial deltoid injury (group 2) and deep deltoid injury (group 3) in partial DL injury, with a measured MCS between 2.5 and 3.5 mm. The intraclass correlation coefficient of interrater reliability was 0.975 for arthroscopy, 0.917 for ERS radiography, and 0.811 for GS radiography.

CONCLUSION

Arthroscopic MCS measurement can differentiate intact DL, partial DL injury, and complete DL injury. Compared with ERS and GS radiography, arthroscopic MCS measurement has greater accuracy with excellent interrater reliability.

CLINICAL RELEVANCE

For patients with suspected DL injury, arthroscopic MCS is useful for determining deltoid lesion severity based on defined cutoff values for consideration in preoperative planning to improve surgical outcomes.

Volume measurements on weightbearing computed tomography can detect subtle syndesmotic instability

While weightbearing computed tomography (WBCT) allows three-dimensional (3D) visualization of the distal syndesmosis, image interpretation has largely relied on one-dimensional (1D) distance and, more recently, two-dimensional (2D) area measurements. This study aimed to (1) determine the sensitivity and specificity of 2D area and 3D volume WBCT measurements towards detecting subtle syndesmotic instability, (2) evaluate whether the patterns of changes in the 3D shape of the syndesmosis can be attributed to the type of ligament injury. A total of 24 patients with unilateral subtle syndesmotic instability and 24 individuals with uninjured ankles (controls) with bilateral ankle WBCT were assessed retrospectively. First, 2D areas at 0, 1, 3, 5, and 10 cm, and 3D volumes at 1, 3, 5, and 10 cm above the tibial plafond were measured bilaterally. Secondly, the 3D model of the distal tibiofibular space was created based on WBCT in a subset of 8 out of 24 patients in whom the type of ligament injury was recognized via magnetic resonance imaging. The 3D model of the injured side was superimposed on the uninjured contralateral side to visualize the pattern of changes in different planes. Volume measurement up to 5 cm above the tibial plafond showed the lowest p-value (<0.001 vs. other methods), higher sensitivity (95.8%, 95% confidence interval [CI]: 87.8-100), and specificity (83.3%, 95% CI: 68.4-98.2) for detection of syndesmotic instability. No specific pattern of changes in the 3D shape could be attributed to a type of ligament rupture. We suggest 3D volume measurements, best measured up to 5 cm proximal to the plafond, as a promising means of diagnosing syndesmotic instability, particularly for subtle cases that are hard to detect. Clinical significance: The ability to compare the ankle joints bilaterally in a 3D manner under physiologic weight provided by weightbearing CT has led to a more accurate diagnostic method. Using volumetric measurement up to 5 cm above the tibial plafond showed higher sensitivity and specificity for recognizing an unstable syndesmosis, especially in subtle cases. However, our preliminary investigations showed that the pattern of 3D alterations in the distal tibiofibular joint space based on WBCT images does not indicate the type of syndesmotic ligamentous injury. Our results can also help image viewing programs to improve their measurement tools to facilitate 3D measurement for the syndesmosis as well as other conditions that may benefit from 3D evaluation of the clinical images.

Articular Cartilage of the Syndesmosis: Avoiding Iatrogenic Cartilage Injury During Syndesmotic Fixation

BACKGROUND

The optimal surgical management of syndesmosis injuries consists of internal fixation between the distal fibula and tibia. Much of the available data on this joint details the anatomy of the syndesmotic ligaments. Little is published evaluating the distribution of articular cartilage of the syndesmosis, which is of importance to minimize the risk of iatrogenic damage during surgical treatment. The purpose of this study is to describe the articular cartilage of the syndesmosis.

METHODS

Twenty cadaveric ankles were dissected to identify the cartilage of the syndesmosis. Digital images of the articular cartilage were taken and measured using calibrated digital imaging software.

RESULTS

On the tibial side, distinct articular cartilage extending above the plafond was identified in 19/20 (95%) specimens. The tibial cartilage extended a mean of 6 ± 3 (range, 2-13) mm above the plafond. On the fibular side, 6/20 (30%) specimens demonstrated cartilage proximal to the talar facet, which extended a mean of 24 ± 4 (range, 20-31) mm above the tip of the fibula. The superior extent of the syndesmotic recess was a mean of 10 ± 3 (range, 5-17) mm in height. In all specimens, the syndesmosis cartilage did not extend more than 13 mm proximal to the tibial plafond and the syndesmotic recess did not extend more than 17 mm proximal to the tibial plafond.

CONCLUSION

Syndesmosis fixation placed more than 13 mm proximal to the tibial plafond would have safely avoided the articular cartilage in all specimens and the synovial-lined syndesmotic recess in most.

CLINICAL RELEVANCE

This study details the articular anatomy of the distal tibiofibular joint and provides measurements that can guide implant placement during syndesmotic fixation to minimize the risk of iatrogenic cartilage damage.

Evidence-Based Surgical Treatment Algorithm for Unstable Syndesmotic Injuries

Background: Surgical treatment of unstable syndesmotic injuries is not trivial, and there are no generally accepted treatment guidelines. The most common controversies regarding surgical treatment are related to screw fixation versus dynamic fixation, the use of reduction clamps, open versus closed reduction, and the role of the posterior malleolus and of the anterior inferior tibiofibular ligament (AITFL). Our aim was to draw important conclusions from the pertinent literature concerning surgical treatment of unstable syndesmotic injuries, to transform these conclusions into surgical principles supported by the literature, and finally to fuse these principles into an evidence-based surgical treatment algorithm. Methods: PubMed, Embase, Google Scholar, The Cochrane Database of Systematic Reviews, and the reference lists of systematic reviews of relevant studies dealing with the surgical treatment of unstable syndesmotic injuries were searched independently by two reviewers using specific terms and limits. Surgical principles supported by the literature were fused into an evidence-based surgical treatment algorithm. Results: A total of 171 articles were included for further considerations. Among them, 47 articles concerned syndesmotic screw fixation and 41 flexible dynamic fixations of the syndesmosis. Twenty-five studies compared screw fixation with dynamic fixations, and seven out of these comparisons were randomized controlled trials. Nineteen articles addressed the posterior malleolus, 14 the role of the AITFL, and eight the use of reduction clamps. Anatomic reduction is crucial to prevent posttraumatic osteoarthritis. Therefore, flexible dynamic stabilization techniques should be preferred whenever possible. An unstable AITFL should be repaired and augmented, as it represents an important stabilizer of external rotation of the distal fibula. Conclusions: The current literature provides sufficient arguments for the development of an evidence-based surgical treatment algorithm for unstable syndesmotic injuries.

Anatomical reconstruction of the anterior inferior tibiofibular ligament in elite athletes using InternalBrace suture tape

AIMS

The ideal management of acute syndesmotic injuries in elite athletes is controversial. Among several treatment methods used to stabilize the syndesmosis and facilitate healing of the ligaments, the use of suture tape (InternalBrace) has previously been described. The purpose of this study was to analyze the functional outcome, including American Orthopaedic Foot & Ankle Society (AOFAS) scores, knee-to-wall measurements, and the time to return to play in days, of unstable syndesmotic injuries treated with the use of the InternalBrace in elite athletes.

METHODS

Data on a consecutive group of elite athletes who underwent isolated reconstruction of the anterior inferior tibiofibular ligament using the InternalBrace were collected prospectively. Our patient group consisted of 19 elite male athletes with a mean age of 24.5 years (17 to 52). Isolated injuries were seen in 12 patients while associated injuries were found in seven patients (fibular fracture, medial malleolus fracture, anterior talofibular ligament rupture, and posterior malleolus fracture). All patients had a minimum follow-up period of 17 months (mean 27 months (17 to 35)).

RESULTS

All patients returned to their pre-injury level of sports activities. One patient developed a delayed union of the medial malleolus. The mean return to play was 62 days (49 to 84) for isolated injuries, while the patients with concomitant injuries returned to play in a mean of 104 days (56 to 196). The AOFAS score returned to 100 postoperatively in all patients. Knee-to-wall measurements were the same as the contralateral side in 18 patients, while one patient lacked 2 cm compared to the contralateral side.

CONCLUSION

This study suggests the use of the InternalBrace in the management of unstable syndesmotic injuries offers an alternative method of stabilization, with good short-term results, including early return to sports in elite athletes. Cite this article: Bone Joint J 2022;104-B(1):68-75.

Bilateral ankle syndesmosis injury: a rare case report

This report describes a case of bilateral acute ankle syndesmosis injuries in a 15-year-old male basketball player. The patient had a background of previous inversion injuries but no symptoms of chronic pain or instability. The case report illustrates the importance of clinical suspicion when evaluating acute syndesmosis injuries in conjunction with radiographic assessments in primary care. This is the first reported case of such injury in bilateral limbs.

Suture Button versus Screw Fixation for Distal Tibiofibular Injury and Expected Value Decision Analysis

Patient preference for fixation technique of syndesmotic injury in the presence of an ankle fracture is not known. This study followed a five-step process for expected value decision analysis: decision tree, outcome probabilities, expected patient values, foldback analysis, and sensitivity analysis. Outcome variables were "well" (cases that did not require further procedures or suffer any complications related to surgery), surgical site infection (SSI), loss of reduction (LOR), hardware removal (HWR), and malreduction. The systematic review included 22 studies including 358 patients who underwent suture button fixation and 739 who underwent screw fixation. Outcome probabilities for suture button fixation were 76.4% well, 6.2% SSI, 5.4% LOR, 10.4% HWR, and 1.6% malreduction. Outcome probabilities for screw fixation were 47.1% well, 4.3% SSI, 8.1% LOR, 30.7% HWR, and 9.8% malreduction. After the survey and foldback analysis, overall utility values for suture button and screw fixation were 7.46 and 4.78, respectively. One-way sensitivity analysis revealed that the overall utility value for suture button fixation was greater than the utility value of screw fixation under all circumstances except when the rate of malreduction for suture button fixation was theoretically elevated to 85%. Level of evidence: therapeutic, level IV.

Anatomic and Radiographic Safe Zone for Posterior Malleolar Screw Placement

BACKGROUND

The most appropriate treatment and management of posterior malleolar fractures (PMFs) lacks consensus. Indirect reduction and fixation with posterior to anterior (PA) screw shows promise by avoiding the risks associated with direct reduction or indirect anterior to posterior approaches. Some authors have raised concerns about potential risk to nearby structures with the PA technique, including hardware prominence into the syndesmosis. This study highlights use of the posteromedial vertical syndesmotic line (PVSL) as a fluoroscopic landmark, helping surgeons avoid intrasyndesmotic placement. Study aims are to evaluate PVSL correspondence with posterior border of the incisura tibialis and to define a safe zone between this line and flexor hallucis longus tendon.

METHODS

Indirect PA screw placement was completed on 10 cadaveric specimens, followed by fluoroscopy in mortise and lateral views. Dissection was performed to assess screw placement relative to the posteromedial border of the syndesmosis. The posterior border of the syndesmosis was marked with a radiopaque wire. Repeat imaging was completed to validate the fluoroscopic PVSL is representative of the posteromedial border of the tibial incisura.

RESULTS

On dissection, 9 out of 10 cadavers had accurate screw placement with no penetration into the syndesmosis. Corresponding imaging showed the screw head to be medial to the marker on mortise view. For the specimen with penetration into the syndesmosis, imaging confirmed that the screw head was lateral to the marker on mortise views. The radiopaque marker correlated with the PVSL for all specimens when comparing anatomic to radiographic findings. A radiographic safe zone is defined for the PA screw 12 mm medial to the PVSL to ensure no iatrogenic injury to the flexor hallucis longus tendon.

CONCLUSION

This study demonstrated that a posterior incisura tibialis fluoroscopic landmark is unambiguous in localizing the posterior syndesmotic border and that screws medial to this line are safely out of the syndesmosis, while screws placed lateral are either in or at risk of intrasyndesmotic placement. A safe zone is defined for screw placement.

CLINICAL RELEVANCE

This article describes a radiographic and clinical safe zone for fixation and hardware placement during open reduction internal fixation (ORIF) of PMFs. This information will assist surgeons in avoiding intrasyndesmotic hardware placement as well as injury to deep soft tissue structures.

Four-Dimensional CT Analysis of Normal Syndesmotic Motion

BACKGROUND

The syndesmosis ligament complex stabilizes the distal tibiofibular joint while allowing for small amounts of physiologic motion. When injured, malreduction of the syndesmosis is the most important factor that contributes to inferior functional outcomes. Syndesmotic reduction is a dynamic measure, which is not adequately captured by conventional computed tomography (CT). Four-dimensional CT (4DCT) can image joints as they move through range of motion (ROM). The aim of this study was to employ 4DCT to determine in vivo syndesmotic motion with ankle ROM in uninjured ankles.

METHODS

Uninjured ankles were analyzed in patients who had contralateral syndesmotic injuries, as well as a cohort of healthy volunteers with bilateral uninjured ankles. Bilateral ankle 4DCT scans were performed as participants moved their ankles between maximal dorsiflexion and plantarflexion. Multiple measures of syndesmotic width, as well as sagittal translation and fibular rotation, were automatically extracted from 4DCT using a custom program to determine the change in syndesmotic position with ankle ROM.

RESULTS

Fifty-eight ankles were analyzed. Measures of syndesmotic width decreased by 0.7 to 1.1 mm as the ankle moved from dorsiflexion to plantarflexion (P < .001 for each measure). The fibula externally rotated by 1.2 degrees with ankle ROM (P < .001), but there was no significant motion in the sagittal plane (P = .43). No participants with bilateral uninjured ankles had a side-to-side difference in syndesmotic width of 2 mm or greater.

CONCLUSION

4DCT allows accurate, in vivo syndesmotic measurements, which change with ankle ROM, confirming prior work that was limited to biomechanical studies. Side-to-side syndesmotic measurements are consistent within subjects, validating the method of templating syndesmotic reduction off the contralateral ankle, in a consistent ankle position, to achieve anatomic reduction of syndesmotic injury.

LEVEL OF EVIDENCE

Level II, prospective cohort study.

Sub-Acute Syndesmotic Injury: A Review and Proposed Treatment Algorithm

Sub-acute syndesmotic injuries are classified as from six weeks to six months from the initial injury date and can be considered a distinct group of patients; however, they are often mistreated and progress to chronic injuries with significant sequelae. The authors performed a comprehensive literature search on the MEDLINE database. The search yielded 165 studies up to January 2021, after the application of inclusion/exclusion criteria. This yielded 10 studies with a total of 156 relevant patients for review. We found that a delay in diagnosis is common and has a negative impact on outcomes. If a sub-acute syndesmotic injury is suspected and plain radiographs are inconclusive, magnetic resonance imaging is indicated if there is still an index of suspicion. Surgical intervention should aim to restore normal length and rotational alignment of the fibula whilst also addressing the need to debride tissues within the joint and syndesmosis. Syndesmosis must then be adequately reduced and stabilised with syndesmotic screw fixation, and augmentation with tendon/ligament reconstruction should be considered. All studies showed an average improvement in functional outcome measures post-operatively. The only study to compare sub-acute and chronic patients' functional outcomes post-operatively showed significant improvement in the sub-acute cohort; highlighting the importance of early intervention. We suggest a treatment algorithm that may help with the diagnosis and management of these injuries. We believe this will help all healthcare professionals to standardise care. Further research is required to assess sub-acute injury outcomes with tendon/ligamentous augmented reconstruction, as no level 1 or 2 studies currently exist.