Role of the Deltoid Ligament in Syndesmotic Instability

2018 ◽  
Vol 39 (5) ◽  
pp. 598-603 ◽  
Author(s):  
Jafet Massri-Pugin ◽  
Bart Lubberts ◽  
Bryan G. Vopat ◽  
Jonathon C. Wolf ◽  
Christopher W. DiGiovanni ◽  
...  
Keyword(s):  
Lateral Force ◽  
Coronal Plane ◽  
Deltoid Ligament ◽  
Lateral Stress ◽  
Interosseous Ligament ◽  
Intact State ◽  
Tibiofibular Ligament ◽  
Anterior Inferior Tibiofibular Ligament ◽  
Cadaveric Model

Background: The deltoid ligament (DL) is the principal ligamentous stabilizer of the medial ankle joint. Little is known, however, about the contribution of the DL toward stabilizing the syndesmosis. The aim of this study was to arthroscopically evaluate whether the DL contributes to syndesmotic stability in the coronal plane. Methods: Eight above-knee cadaveric specimens were used in this study. A lateral hook test was performed by applying 100 N of lateral force to the fibula in the intact state and after sequential transection of the DL, anterior-inferior tibiofibular ligament (AITFL), interosseous ligament (IOL), and posterior-inferior tibiofibular ligament (PITFL). At each stage, distal tibiofibular diastasis was measured arthroscopically at both the anterior and posterior third of the incisura and compared to stress measurements of the intact syndesmosis. Measurements were performed using probes ranging from 0.1 to 6.0 mm, with 0.1-mm increments. Results: There was no significant increase in diastasis at either the anterior or posterior third of the tibiofibular articulation after isolated DL disruption, nor when combined with AITFL transection. In contrast, a significant increase in diastasis was observed following additional disruption of the IOL (anterior and posterior third diastasis, P= .012 and .026, respectively), and after transection of all 3 syndesmotic ligaments (anterior and posterior third diastasis, P=.001 and .001, respectively). Conclusion: When evaluating the syndesmosis arthroscopically in a cadaveric model under lateral stress, neither isolated disruption of the DL nor combined DL and AITFL injuries destabilized the syndesmosis in the coronal plane. In contrast, the syndesmosis became unstable if the DL was injured in conjunction with partial syndesmotic disruption that included the AITFL and IOL. Clinical relevance: Disruption of the DL appeared to destabilize the syndesmosis in the coronal plane when associated with partial disruption of the syndesmosis (AITFL and IOL).

Do Coronal or Sagittal Plane Measurements Have the Highest Accuracy to Arthroscopically Diagnose Syndesmotic Instability?

2021 ◽  
pp. 107110072110041
Author(s):  
Rohan Bhimani ◽  
Bart Lubberts ◽  
Pongpanot Sornsakrin ◽  
Jafet Massri-Pugin ◽  
Gregory Waryasz ◽  
...  
Keyword(s):  
Operating Characteristic ◽  
Sagittal Plane ◽  
Area Under The Curve ◽  
Coronal Plane ◽  
Deltoid Ligament ◽  
Roc Curve Analysis ◽  
Level Of Evidence ◽  
Interosseous Ligament ◽  
Tibiofibular Ligament ◽  
Anterior Inferior Tibiofibular Ligament

Background: To compare the accuracy of arthroscopic sagittal versus coronal plane distal tibiofibular motion toward diagnosing syndesmotic instability. Methods: Arthroscopic assessment of the syndesmosis was performed on 21 above-knee cadaveric specimens, first with all ligaments intact and subsequently with sequential transection of the anterior inferior tibiofibular ligament, the interosseous ligament, the posterior inferior tibiofibular ligament, and the deltoid ligament. A lateral hook test, an anterior-to-posterior (AP) translation test, and a posterior-to-anterior (PA) translation test were performed under 100 N of applied force. Anterior and posterior third coronal plane diastasis and AP and PA sagittal plane fibular translations were measured relative to the static tibia. Results: Receiver operating characteristic (ROC) curve analysis revealed that the area under the curve (AUC) was higher for the combined AP and PA sagittal measurements (AUC, 0.91; accuracy, 83.5%; sensitivity, 78%; specificity, 89%) than the coronal plane measurements (anterior third: AUC, 0.65; accuracy, 60.5%; sensitivity, 63%; specificity, 59%; posterior third: AUC, 0.73; accuracy, 68.5%; sensitivity, 80%; specificity, 57%) ( P < .001), underscoring the higher accuracy of sagittal plane measurements. Conclusion: Arthroscopic measurement of sagittal plane fibular translation is more accurate than coronal plane diastasis for evaluating syndesmotic instability. Clinical Relevance: Clinicians should focus on distal tibiofibular motion in the sagittal plane when arthroscopically evaluating suspected syndesmotic instability. Level of Evidence: Biomechanical cadaveric study.

Arthroscopic Assessment of Syndesmotic Instability in the Sagittal Plane in a Cadaveric Model

2019 ◽  
Vol 41 (2) ◽  
pp. 237-243 ◽  
Author(s):  
Bart Lubberts ◽  
Jafet Massri-Pugin ◽  
Daniel Guss ◽  
Jonathon C. Wolf ◽  
Rohan Bhimani ◽  
...  
Keyword(s):  
Sagittal Plane ◽  
Cutoff Point ◽  
Ligament Injury ◽  
Deltoid Ligament ◽  
Optimal Cutoff ◽  
Distal Fibula ◽  
Interosseous Ligament ◽  
Tibiofibular Ligament ◽  
Optimal Cutoff Point ◽  
Cadaveric Model

Background: Syndesmotic instability is multidirectional, occurring in the coronal, sagittal, and rotational planes. Despite the multitude of studies examining such instability in the coronal plane, other studies have highlighted that syndesmotic instability may instead be more evident in the sagittal plane. The aim of this study was to arthroscopically assess the degree of syndesmotic ligamentous injury necessary to precipitate fibular translation in the sagittal plane. Methods: Twenty-one above-knee cadaveric specimens underwent arthroscopic evaluation of the syndesmosis, first with all syndesmotic and ankle ligaments intact and subsequently with sequential sectioning of the anterior inferior tibiofibular ligament (AITFL), the interosseous ligament (IOL), the posterior inferior tibiofibular ligament (PITFL), and deltoid ligament (DL). In all scenarios, an anterior to posterior (AP) and a posterior to anterior (PA) fibular translation test were performed under a 100-N applied force. AP and PA sagittal plane translation of the distal fibula relative to the fixed tibial incisura was arthroscopically measured. Results: Compared with the intact ligamentous state, there was no difference in sagittal fibular translation when only 1 or 2 ligaments were transected. After transection of all the syndesmotic ligaments (AITFL, IOL, and PITFL) or after partial transection of the syndesmotic ligaments (AITFL, IOL) alongside the DL, fibular translation in the sagittal plane significantly increased as compared with the intact state ( P values ranging from .041 to <.001). The optimal cutoff point to distinguish stable from unstable injuries was equal to 2 mm of fibular translation for the total sum of AP and PA translation (sensitivity 77.5%; specificity 88.9%). Conclusion: Syndesmotic instability appears in the sagittal plane after injury to all 3 syndesmotic ligaments or after partial syndesmotic injury with concomitant deltoid ligament injury in this cadaveric model. The optimal cutoff point to arthroscopically distinguish stable from unstable injuries was 2 mm of total fibular translation. Clinical Relevance: These data can help surgeons arthroscopically distinguish between stable syndesmotic injuries and unstable ones that require syndesmotic stabilization.

scholarly journals Arthroscopic Characterization of Syndesmotic Instability

2018 ◽  
Vol 3 (2) ◽  
pp. 2473011418S0000
Author(s):  
Mohamed Abdelaziz ◽  
Jafet Massri-Pugin ◽  
Bart Lubberts ◽  
Bryan Vopat ◽  
Daniel Guss ◽  
...  
Keyword(s):  
Confidence Interval ◽  
Stress Test ◽  
Ankle Arthroscopy ◽  
Coronal Plane ◽  
Ligament Injury ◽  
Deltoid Ligament ◽  
Interosseous Ligament ◽  
P Values ◽  
Intact State ◽  
Lateral Incision

Category: Arthroscopy, Sports, Trauma, Other, Syndesmosis Introduction/Purpose: Ankle arthroscopy is increasingly used to diagnose syndesmostic instability by visualizing the distal tibiofibular articulation and applying a lateral fibular stress. Precisely where in the incisura one should measure potential diastasis, however, remains unclear. The purpose of this study was to determine where within the incisura one should assess coronal plane instability in purely ligamentous syndesmotic injuries when performing a lateral hook stress test (LHT). Methods: Twenty-two above-knee cadaveric specimens underwent ankle arthroscopy, first with intact ligaments and thereafter after each sequential step of syndesmotic and deltoid ligament transection. At each step, a standard 100 N hook test was applied through a lateral incision 5 cm proximal to the ankle joint and the coronal plane diastasis in the stressed and unstressed states were measured at both anterior and posterior third of the distal tibiofibular joint using calibrated probes ranged from 0.1 to 6.0 mm, with 0.1 mm of increments. Results: Anterior third diastasis did not change significantly when applying a LHT, neither in the intact state nor after any stage of ligament transection (P values ranging from p=0.61 to p=0.94). In contrast, posterior third diastasis increased significantly by applying stress at the intact state at the following stages of transection: posterior-inferior tibiofibular ligament (PITFL), PITFL plus interosseous ligament, all syndesmosis ligaments, and all syndesmosis ligaments plus superficial and deep deltoid ligament (P values ranging p=0.001 to p=0.031). Interobserver agreement was substantial (ICC = 0.81; 95% confidence interval, 0.44-0.92), and moderate (ICC = 0.73; 95% confidence interval, 0.36-0.87) for anterior and posterior third diastasis measurements, respectively. Conclusion: Syndesmotic ligament injury results in coronal plane instability of the distal tibiofibular articulation that is readily identified arthroscopically with a LHT and when measured in the posterior third of the incisura. Measurement at the anterior third of the incisura may miss such injuries.

Arthroscopic Correlates of Subtle Syndesmotic Injury

2017 ◽  
Vol 38 (5) ◽  
pp. 502-506 ◽  
Author(s):  
Gregory P. Guyton ◽  
Kenneth DeFontes ◽  
Cameron R. Barr ◽  
Brent G. Parks ◽  
Lyn M. Camire
Keyword(s):  
External Rotation ◽  
Objective Measure ◽  
High Likelihood ◽  
Interosseous Ligament ◽  
Intact State ◽  
Spherical Probe ◽  
Tibiofibular Ligament ◽  
Tibiofibular Joint ◽  
Anterior Inferior Tibiofibular Ligament ◽  
Standardized Measurement

Background: Arthroscopic criteria for identifying syndesmotic disruption have been variable and subjective. We aimed to quantify syndesmotic disruption arthroscopically using a standardized measurement device. Methods: Ten cadaveric lower extremity specimens were tested in intact state and after serial sectioning of the syndesmotic structures (anterior inferior tibiofibular ligament [AiTFL], interosseous ligament [IOL], posterior inferior tibiofibular ligament [PiTFL], deltoid). Diagnostic ankle arthroscopy was performed after each sectioning. Manual external rotational stress was applied across the tibiofibular joint. Custom-manufactured spherical balls of increasing diameter mounted on the end of an arthroscopic probe were inserted into the tibiofibular space to determine the degree of diastasis of the tibiofibular joint under each condition. Results: A ball 3 mm in diameter reliably indicated a high likelihood of combined disruption of the AiTFL and IOL. Disruption of the AiTFL alone could not be reliably distinguished from the intact state. Conclusion: Use of a spherical probe placed into the tibiofibular space during manual external rotation of the ankle provided an objective measure of syndesmotic instability. Passage of a 2.5-mm probe indicated some disruption of the syndesmosis, but the test had poor negative predictive value. Passage of a 3.0-mm spherical probe indicated very high likelihood of disruption of both the AiTFL and the IOL. Clinical Relevance: The findings challenge the previously used but unsupported standard of a 2-mm diastasis of the tibiofibular articulation for diagnosis of subtle syndesmotic instability.

scholarly journals Effect of a Controlled Ankle Motion Walking Boot on Syndesmotic Instability During Weightbearing: A Cadaveric Study

2019 ◽  
Vol 7 (8) ◽  
pp. 232596711986401 ◽  
Author(s):  
Stéphanie Lamer ◽  
Jonah Hébert-Davies ◽  
Vincent Dubé ◽  
Stéphane Leduc ◽  
Émilie Sandman ◽  
...  
Keyword(s):  
External Rotation ◽  
Axial Loading ◽  
Interosseous Ligament ◽  
Ankle Motion ◽  
Paired Samples ◽  
Tibiofibular Ligament ◽  
Custom Made ◽  
Anterior Inferior Tibiofibular Ligament ◽  
Careful Management

Background: Syndesmotic injuries can lead to long-term complications; hence, they require careful management. Conservative treatment is adequate when 1 syndesmotic ligament is injured, but surgery is often necessary to achieve articular congruity when 3 syndesmotic ligaments are ruptured. However, there is some controversy over the best treatment for 2-ligament injuries. Purpose: To evaluate the effect of a controlled ankle motion (CAM) walking boot on syndesmotic instability following iatrogenic isolated anterior inferior tibiofibular ligament (AiTFL) injury and combined AiTFL/interosseous ligament (IOL) injuries in a cadaveric simulated weightbearing model. Study Design: Controlled laboratory study. Methods: Ten cadaveric specimens were dissected to expose the tibial plateau and syndesmosis. The specimens were fitted to a custom-made device, and a reproducible axial load of 750 N was applied. Iatrogenic rupture of the syndesmotic ligaments (AiTFL + IOL) was done sequentially. Uninjured syndesmoses, isolated AiTFL rupture, and combined AiTFL/IOL rupture were compared with and without axial loading (AL) and CAM boot. The distal tibiofibular relationship was evaluated using a previously validated computed tomography scan measurement system. Wilcoxon tests for paired samples and nonparametric data were used. Results: The only difference noted in the distal tibiofibular relationship during AL was an increase in the external rotation of the fibula when using the CAM boot. This was observed with AiTFL rupture (8.40° vs 11.17°; P = .009) and combined AiTFL/IOL rupture (8.81° vs 11.97°; P = .005). Conclusion: AL did not cause a significant displacement between the tibia and fibula, even when 2 ligaments were ruptured. However, the CAM boot produced a significant external rotation with 1 or 2 injured ligaments. Clinical Relevance: Further studies are needed to assess the capacity of the CAM walking boot to prevent malreduction when external rotation forces are applied to the ankle. Moreover, special care should be taken during the fitting of the CAM boot to avoid overinflation of the cushions.

Ankle Injuries During Excessive External Foot Rotation May Depend on Foot Constraint: Development of a Computational Model

2010 ◽  
Author(s):  
Feng Wei ◽  
John W. Powell ◽  
Roger C. Haut
Keyword(s):  
Computational Model ◽  
Bone Fracture ◽  
Clinical Studies ◽  
External Rotation ◽  
Ankle Injuries ◽  
Deltoid Ligament ◽  
Calcaneofibular Ligament ◽  
Tibiofibular Ligament ◽  
Posterior Talofibular Ligament

Numerous studies on the mechanisms of ankle injury deal with injuries to the syndesmosis and anterior ligamentous structures, but previous sectioning and clinical studies also describe the important role of the posterior talofibular ligament (PTaFL) in the ankle’s resistance to external rotation of the foot. Foot constraint may influence subtalar motion and the movement of the bones in the foot, thereby influencing the mode of injury during external rotation [1]. Stiehl et al. [2] constrain the foot with fiberglass cast tape, externally rotate the foot 90°, and produce injury to the deltoid ligament and anterior tibiofibular ligament (ATiFL) with bone fracture. In contrast, Stormont et al. [3] fix the foot in a potting alloy and conclude the primary ligamentous restraints to external rotation are the PTaFL and calcaneofibular ligament (CaFL).

scholarly journals New “Freer test” for assessment of syndesmotic diastasis -Cadaveric study

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0029
Author(s):  
Jinsu Kim ◽  
Young-uk Park ◽  
Kyung-tai Lee ◽  
Kiwon Young ◽  
Sang Lee
Keyword(s):  
Diagnostic Value ◽  
Type B ◽  
Interosseous Ligament ◽  
Firm Structure ◽  
Tibiofibular Ligament ◽  
Fibular Fracture ◽  
Probe Test ◽  
Anterior Inferior Tibiofibular Ligament ◽  
Weber Type ◽  
Fibular Fixation

Category: Sports Introduction/Purpose: Syndesmotic stability is usually assessed arthroscopically by an arthroscopic probe insertion between the anterolateral tibio-fibular recess. This probe test can predict the syndesmotic instability, however, is difficult to determine syndesmotic fixation. The syndesmosis has dynamic motion and fairly firm structure, 2 mm thin probe cannot make syndesmotic dynamic diastasis. We proposed a new “Freer test” for diagnosis of syndesmosis injury which performed to insert a 2 mm diameter freer elevator between tibio-fibular lateral gutter while keeping the ankle at the plantigrade. The purpose of the present study was to evaluate the diagnostic value of freer test for anterior inferior tibiofibular ligament (AITFL) complete tear, interosseous ligament (IOL) tear and Weber type B fibular fracture. Methods: Ten fresh ankle cadaveric specimens were used. Operative procedures progressed as below; firstly, exposed antero-lateral ankle joint with direct lateral longitudinal incision, incised AITFL, incised IOL, performed Weber type B osteotomy at fibular, fixed the osteomized fibular with 8-hole locking plate and fixed the AITFL with suture anchors. In each procedure, freer tests with ankle dorsiflexion (DF, plantigrade) and plantarflexion (PF) were performed with freer elevator linked 3 kgf compression gauge. A negative test was defined as the freer did not insert with a more than 3 kgf. A positive test was defined lesser than 3 kgf, and measured the force at the insertion. Results: All freer test was negative with DF before procedures. Six ankles with PF were positive with average 1.5 kgf. All freer test positive has shown after AITFL cutting in DF, PF(mean 1.76 kgf, 1.19 kgf). After IOL cutting, all freer tests were positive in DF, PF(mean 1.46, 0.79 kgf). After fibular osteotomy, all freer tests were positive in DF, PF (mean 0.83,0.18 kgf). After fibular fixation with plate, all freer tests were positive in DF, PF (mean 1.26, 0.97 kgf). After syndesmotic fixation with anchors, 8 freer tests were positive in DF. 2 negative in PF, 4 negative in PF and 6 positive in PF. 2 positive in DF had partial breakage on anchor footprint due to weak bone. Conclusion: The “freer test” is useful diagnostic tool which test positive means AITFL rupture.

scholarly journals Peritalar Kinematic Changes Associated with Increased Spring Ligament Tear in Cadaveric Flatfoot Model

2018 ◽  
Vol 3 (3) ◽  
pp. 2473011418S0032 ◽  
Author(s):  
Ashlee MacDonald ◽  
David Cifo ◽  
Emma Knapp ◽  
Hani Awad ◽  
John Ketz ◽  
...  
Keyword(s):  
Cyclic Loading ◽  
Coronal Plane ◽  
Abduction Angle ◽  
Deltoid Ligament ◽  
Interosseous Ligament ◽  
Ligament Tear ◽  
Spring Ligament ◽  
Valgus Angle ◽  
Valgus Alignment ◽  
Tear Size

Category: Hindfoot Introduction/Purpose: Adult Acquired Flatfoot Deformity (AAFD) is a complex and progressive deformity characterized by abduction of the midfoot and valgus alignment of the hindfoot. Spring ligament tear is often present in advanced stages of the AAFD. Previous anatomic studies have demonstrated that the superficial deltoid ligament blends with the superomedial spring ligament to provide both medial tibiotalar and talonavicular stability aiding in coronal plane stability. Given that the spring ligament blends with the superficial deltoid ligament, we sought to investigate the kinematic effect of spring ligament tear in development of peritalar instability in cadaveric flatfoot model. We hypothesized that increased spring ligament tear size will result in increased talonavicular joint abduction (axial) and plantarflexion (sagittal), and increased valgus alignment of the tibiotalar and subtalar joints (coronal). Methods: Seven fresh-frozen cadaveric foot specimens were employed. Reflective markers were mounted on the tibia, talus, navicula, calcaneus and the first metatarsus. Kinematics of the peritalar joints were captured by multiple camera motion capture system. A flatfoot model was created by sectioning the medial and inferior talonavicular interosseous ligament, followed by cyclic axial load of 1150 N under a hydraulic loading frame with 350 N load applied to the Achilles tendon. The talo-first metatarsus (T- 1MT) abduction angle was calculated and cycles were applied until abduction of 5-10° (mild flatfoot) was achieved. Spring ligament sectioning was extended 1 cm proximally along the superomedial ligament followed by cyclic loading until 10-15° (moderate) of T- 1MT abduction was achieved. The spring ligament was sectioned for another 1 cm followed by cyclic loading until >15° (severe) abduction was noted. The relative kinematic changes were compared among the initial, mild, moderate, and severe flatfoot model using two-way ANOVA. Results: The average T-1MT abduction angles in the mild, moderate, and severe flatfoot were 7.79°+/-2.27°, 11.47°+/-2.82°, and 15.46°+4.15°. Meary’s angle increased with progression of the flatfoot (mild 6.17°+/-2.92°, moderate 9.71°+/-3.4°, severe 12.46°+/-4.13°). Hindfoot valgus angle also increased. The mild, moderate, and severe flatfoot showed 2.4°+/-3.85°, 4.13°+/-3.9°, and 4.75°+/-3.79° of tibiotalar valgus angle. The subtalar joint exhibited 2.94°+/-3.41°, 5.52°+/-4.34°, and 6.97°+/-4.83° valgus angle in the mild, moderate, and severe models. The T-1MT abduction angle and Meary’s angle were significantly different in all flatfoot models compared to the initial condition (p<0.001), and the severe vs. mild models (p<0.01). Tibiotalar valgus was significantly increased in severe compared to the initial model (p=0.02). Subtalar valgus angle significantly increased in the moderate and severe models compared to the initial (p<0.01, p<0.001). Conclusion: Serial increment in spring ligament tear size in simulated flatfoot increased relative talus adduction and plantarflexion. It also resulted in gradual increment of valgus alignment of the tibiotalar and subtalar joints in coronal plane. This finding demonstrates that a large spring ligament tear in advanced stage AAFD leads to increased strain across the medial peritalar ligaments. In addition to osseous correction and tendon transfer, medial ligament augmentation, may be a critical component in surgical correction of AAFD with a large spring ligament tear.

Magnetic Resonance Imaging of Acute Maisonneuve Fractures

1996 ◽  
Vol 17 (5) ◽  
pp. 259-263 ◽  
Author(s):  
John R. Morris ◽  
Jackson Lee ◽  
David Thordarson ◽  
Michael R. Terk ◽  
Marshall Brustein
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Interosseous Membrane ◽  
Deltoid Ligament ◽  
Anterior Talofibular Ligament ◽  
Resonance Imaging ◽  
Calcaneofibular Ligament ◽  
Interosseous Ligament ◽  
Proximal Fibula ◽  
Tibiofibular Ligament

Magnetic resonance imaging (MRI) studies were performed on five patients with acute Maisonneuve fractures. All patients had sustained a twisting injury to their ankles and complained of ankle pain and pain over their proximal fibula. High quality images with excellent visualization of all the ankle ligamentous structures were obtained. MRI showed that the anterior inferior tibiofibular ligament was disrupted in ail patients and the posterior inferior tibiofibular ligament was intact in three of five patients. Also, the anterior talofibular ligament was disrupted in all patients and the calcaneofibular ligament was ruptured in two of five patients. This raises the question of whether patients with Maisonneuve fractures have lateral ankle instability at long-term follow-up. Although the superficial deltoid ligament was disrupted in all patients, the deep deltoid ligament was intact in one patient, partially disrupted in one patient, and completely disrupted in three patients. The interosseous ligament was disrupted at the ankle in all patients, while the interosseous membrane was disrupted in the leg in all patients except one. This patient had an intact interosseous membrane despite rupture of the interosseous ligament at the ankle, and the presence of a proximal one third fibula fracture.

Impact of Torque on Assessment of Syndesmotic Injuries Using Weightbearing Computed Tomography Scans

2019 ◽  
Vol 40 (6) ◽  
pp. 710-719 ◽  
Author(s):  
Nicola Krähenbühl ◽  
Travis L. Bailey ◽  
Maxwell W. Weinberg ◽  
Nathan P. Davidson ◽  
Beat Hintermann ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Axial Load ◽  
External Rotation ◽  
Ct Scans ◽  
Deltoid Ligament ◽  
Tibiofibular Syndesmosis ◽  
Tibiofibular Ligament ◽  
Distal Tibiofibular Syndesmosis ◽  
Axial Ct ◽  
The Impact

Background: The diagnosis of subtle injuries to the distal tibiofibular syndesmosis remains elusive. Conventional radiographs miss a large subset of injuries that present without frank diastasis. This study evaluated the impact of torque application on the assessment of syndesmotic injuries when using weightbearing computed tomography (CT) scans. Methods: Seven pairs of male cadavers (tibia plateau to toe-tip) were included. CT scans with axial load application (85 kg) and with (10 Nm) or without torque to the tibia (corresponding to external rotation of the foot and ankle) were taken during 4 test conditions. First, intact ankles (native) were scanned. Second, 1 specimen from each pair underwent anterior inferior tibiofibular ligament (AITFL) transection (condition 1A), while the contralateral underwent deltoid transection (condition 1B). Third, the lesions were reversed on the same specimens and the remaining intact deltoid or AITFL was transected (condition 2). Finally, the distal tibiofibular interosseous membrane (IOM) was transected in all ankles (condition 3). Measurements were performed to assess the integrity of the distal tibiofibular syndesmosis on digitally reconstructed radiographs (DRRs) and on axial CT scans. Results: Torque impacted DRR and axial CT scan measurements in almost all conditions. The ability to diagnose syndesmotic injuries using axial CT measurements improved when torque was applied. No significant syndesmotic morphological change was observed with or without torque for either isolated AITFL or deltoid ligament transection. Discussion: Torque application had a notable impact on two-dimensional (2-D) measurements used to diagnose syndesmotic injuries for both DRRs and axial CT scans. Because weightbearing conditions allow for standardized positioning of the foot while radiographs or CT scans are taken, the combination of axial load and torque application may be desirable. Clinical Relevance: Application of torque to the tibia impacts 2-D measurements and may be useful when diagnosing syndesmotic injuries by DRRs or axial CT images.

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