Fibular Translation Research Articles

Biomechanical profile of varying suture button constructs in cadaveric specimens: a systematic review and meta-analysis.

Suture button fixation of syndesmotic injuries allows for more physiologic motion of the ankle joint while maintaining adequate reduction and may avoid the need for additional surgeries, given the lower risk of syndesmotic diastasis and implant failure. Few studies have examined the optimal number and configuration of suture buttons for syndesmotic disruption. The purpose of this systematic review and meta-analysis is to compare different suture button configurations from the cadaveric literature and to assess their relative effect on the stability of the syndesmotic reduction and functional movement of the ankle. A literature search in the databases MEDLINE via PubMed, Embase via Elsevier, Scopus via Elsevier, and SPORTDiscus via EBSCO were searched through December 2022 to identify studies related to cadaveric modeling of the syndesmosis. Only cadaveric studies with suture button fixation and studies in English were included. The quality of cadaveric studies was assessed using the Quality Assessment for Cadaveric Studies (QUACS) tool. Revman 5.3 software was used to perform the meta-analysis. The meta-analysis included 5 studies and 86 limbs. The systematic review included 15 studies. When comparing single and double suture button configurations, no difference was found between groups with regard to fibular rotation (MD =-0.9; 95% CI: -2.09 to 0.27; I2=79%; P=0.13) and both groups had similar rotational stability. The double suture button technique did demonstrate less sagittal fibular translation compared to the single suture button (MD =0.48; 95% CI: 0.02-0.94; I2=66%; P=0.04). When comparing two suture buttons in parallel and divergent configurations, studies did not find any differences with regard to strength or stability. There were no significant differences in biomechanical parameters when comparing single and double suture button constructs. While single button suture constructs result in minimal fibular rotation, double suture button constructs minimize fibular translation. This review may serve as a guide for clinicians when approaching these injuries.

A Novel Flexible Fixation Method for Syndesmotic Injury.

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. 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. 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. 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 IV, case series.

Imaging Threshold for Assessment of the Correct Reduction in the Treatment of Unstable Syndesmotic Injuries - A Retrospective Analysis of 57 CT Scans.

An incongruence of the distal tibiofibular joint (TFJ) after treatment of upper ankle joint injury represents a prearthrotic deformity and must be corrected. The objectives of this study were to analyze postoperative CT scans after surgical treatment of unstable syndesmotic injuries, and to determine the prevalence of syndesmotic malreduction and its contributing factors. The specific parameters of three-dimensional imaging for objective detection of malreduction should be identified as a helpful intraoperative imaging threshold. Postoperative CT scans of 57 patients were analyzed by identifying cases requiring correction. Factors that influenced the reduction result (patient age, sex, fracture type and surgeon qualifications) were evaluated. The following CT measurements were determined: anterior (AD) and posterior tibiofibular distance (PD), TFJ width, anteroposterior fibular translation (APT), length and rotation of the fibula, position of the malleoli to the talar joint surface. A confidence interval of 95% was assumed (significance level p < 0.05). A very high proportion of the cases required revision (38.5%). Age (p=0.199), sex (p=0.752), body mass (p=0.722), and fracture type (p=0.266) had no significant influence on the reduction result. The risk of requiring correction was slightly lower for well-experienced trauma surgeons. The measurements revealed the following thresholds: AD: ø 3.2 mm (±2.2), PD: ø 5.1 mm (±2.2), TFJ: ø 3.4 mm (±1.4), APT: ø 7.9 mm (±3.5), and rotation: ø 10.7° (±6.8). The fibula was too long in 4 cases (7%) and too short in 8 cases (14%). There was a malleolar incongruence in 5 cases (8.7%). The analysis revealed a significant correlation between the ratio of the anterior and posterior tibiofibular distances and a need for correction. The ratio between the anterior and posterior tibiofibular distances in the axial sectional image is an aid for intraoperative assessment of the correct reduction in the TFJ.

Syndesmosis Instability

The syndesmosis is one of important stabilizer of the ankle joint and consists of a complex ligamentous structure: the anterior inferior tibiofibular ligament; the interosseous ligament; the posterior inferior tibiofibular and the transverse ligaments. The posterior syndesmosis plays the most important role providing 40–45% of the resistance to diastasis, while the AITFL provides around 35%. Major injuries of two of the syndesmosis components represent a loss of more than 50% of resistance to diastasis and may result in instability. Syndesmosis injury or a high ankle sprain, is a frequent athletic trauma accounting for 1% to 18% of all ankle sprains, 17 to 84% of all sport injuries, and 10% of all ankle fractures. Most of the mechanism injury is external rotation injury. A radiographic study suggested that about 20.3% of ankle sprains were combined with a syndesmosis injury. Without proper treatment, the chronic syndesmosis injury remains symptomatic for more than 6 months after the initial trauma, with persistent pain, functional disability, and early-stage ankle arthritis. Normally, syndesmosis widens 1 mm during normal gait. Widening of syndesmosis more than 1 mm can reduce tibiotalar contact surface about 42%. The degenerative changes can occur if the lateral talar shift more than 2 mm. Clinical tests for syndesmosis injuries are external rotation stress test, Cotton test, dorsiflexion-compression test, squeeze test, crossed-leg test, fibular translation and AITFL palpation. Standard radiographs are part of ankle trauma evaluation, especially for fracture exclusion, applying the Ottawa criteria. Computerized tomography (CT) scan is a useful tool to assess tibiofibular diastasis, fibular rotation and joint asymmetry, but shows low sensitivity. MRI is showing very high sensitivity and specificity in identification of syndesmotic injuries. For stable lesion can be treated with conservative means, including non weight bearing or protected weight bearing with a cast or walking boot and a rehabilitation protocol. An unstable lesion requires a surgical procedure to avoid long-term disability and chronic instability. Ankle arthroscopy remains essential for diagnosis and treatment. With accessory tools that measure the syndesmosis gap (e.g. 3.5 mm shaver canula or a metallic tools). Passage of a 3 mm spherical probe during external rotation indicates very high likelihood of rupture of both the AITFL and the IOL. Also, concomitant intra-articular pathologies (osteochondral lesions, other ligamentous rupture or loose bodies) can be presented, with 19% needs to be addressed, reinforcing the role of arthroscopy not only for diagnosis but also for treatment. It is also an excellent tool to evaluate anatomic reduction and residual diastasis.

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

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. 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. 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. 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 II, prospective cohort study.

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.

Isolated injuries to the lateral ankle ligaments have no direct effect on syndesmotic stability.

This study aim was to detect the impact of lateral ankle ligaments injury on syndesmotic laxity when evaluated arthroscopically in a cadaveric model. The null hypothesis was that lateral ankle ligament injury does not affect the stability of syndesmosis. Sixteen fresh-frozen above-knee amputated cadaveric specimens were divided into two groups of eight specimens that underwent arthroscopic evaluation of the distal tibiofibular joint. In both the groups, the assessment was first done with all syndesmotic and ankle ligaments intact. Thereafter, Group 1 underwent sequential transection of the three lateral ankle ligaments first to identify the effects of lateral ligament injury: (1) anterior talofibular ligament (ATFL), (2) calcaneofibular ligament (CFL), (3) posterior talofibular ligament (PTFL), then followed by the syndesmotic ligaments, (4) AITFL, (5) Interosseous ligament (IOL), and (6) PITFL. Group 2 underwent sequential transection of the (1) AITFL, (2) ATFL, (3) CFL, (4) IOL, (5) PTFL, and (6) PITFL, which represent the most commonly injured pattern in ankle sprain. In all scenarios, four loading conditions were considered under 100N of direct force: (1) unstressed, (2) a lateral fibular hook test, (3) anterior to posterior (AP) fibular translation test, and (4) posterior to anterior (PA) fibular translation test. Distal tibiofibular coronal plane diastasis at the anterior and posterior third of syndesmosis, as well as AP and PA sagittal plane translation, were arthroscopically measured. The distal tibiofibular joint remained stable after transection of all lateral ankle ligaments (ATFL, CFL, and PTFL) as well as the AITFL. However, after additional transection of the IOL, the syndesmosis became unstable in both the coronal and sagittal plane. Syndesmosis laxity in the coronal plane was also observed after transection of the ATFL, CFL, AITFL, and IOL. Subsequent transection of the PITFL precipitated syndesmosis laxity in the sagittal plane, as well. The findings from the present study suggest that lateral ankle ligament injuries itself do not directly affect the stability of syndesmosis. However, if it combines with IOL injuries, even partial injuries cause syndesmotic laxity. As a clinical relevance, accurate diagnosis is the key for surgeons to determine syndesmosis fixation whether there is only AITFL injury or combined IOL injury in concomitant acute syndesmotic and lateral ligament injury.

The effect of proximal tibiofibular joint dislocation on knee mechanics: reduction and fixation matters.

Proximal tibiofibular joint (PTFJ) dislocations are under-investigated injuries. There is scant basic science or clinical evidence to direct management. The purpose of this study was twofold; first to investigate the pathomechanics of PTFJ dislocation on knee mechanics. The second purpose was to evaluate knee mechanics following reduction and fixation. Six cadaveric legs were tested on a mechanical platform. A 5Nm external rotation force was applied to each knee and the external rotation and fibular translation was measured for several study conditions at 0°, 30°, and 90° of flexion. Conditions included: the native state, transection of the posterior PTFJ ligament, transection of the anterior and posterior ligaments, screw fixation, and suspensory fixation. Screw fixation was performed using a single quadricortical 3.5mm screw. Suspensory fixation was performed using an Arthrex TightRope device RESULTS: Transection of the anterior and posterior ligaments increased external rotation by 4.3°, 5.9°, and 5.6°, at 0°, 30°, and 90° (p ≤ 0.001), respectively. Screw and suspensory fixation returned external rotation to a near native state with mild overconstraint. Complete transection of anterior and posterior ligaments resulted in pathologic anterior fibular translation of 1.51mm (p = 0.001), 1mm, (p = 0.02) and 0.44mm (p = 0.69) for 0°, 30°, 90° of knee flexion. Screw and suspensory fixation restored native translation at all points with a small degree of overconstraint. Disruption of the PTFJ causes pathologic external rotation and anterior fibular translation. Fixation restores near native motion with minor overconstraint. Surgeons should consider reduction and fixation of PTFJ injuries to restore native knee mechanics.

Changes in the Syndesmotic Reduction After Syndesmotic Suture-Button Fixation for Ankle Malleolar Fractures: 1-Year Longitudinal Evaluations Using Computed Tomography.

Evaluation over time is important in assessing the reduction of the syndesmosis after suture-button fixation for ankle malleolar fractures. The purposes of this study were to evaluate time-dependent change in the syndesmotic reduction immediately after suture-button fixation for ankle malleolus fractures and 1 year after surgery using computed tomography, and to investigate the reliability of the measurement values to evaluate the reduction of syndesmosis. We assessed 28 patients who underwent suture-button fixation for ankle fractures. Syndesmotic reduction was assessed within 2 weeks of the fracture surgery and 1 year after surgery using axial computer tomographic images. Side-to-side differences in the anterior, central, and posterior tibiofibular distances, anteroposterior fibular translation, fibular rotation, and syndesmosis area were measured. The mean anterior tibiofibular distance and anteroposterior fibular translation were 1.8 mm and 1.5 mm, respectively, after syndesmotic fixation. They decreased to 1.2 mm and 0.6 mm, respectively, at 1 year after surgery (P = .03 and P = .01, respectively). The other measurement values did not change over time. The minimum detectable change in the distance of measurements was 1 mm or less. The anterior tibiofibular distance and anteroposterior fibular translation had decreased 1 year after fixation in ankle malleolar fractures with syndesmotic suture button. Even if the fibula is posteriorly malreduced by the time computed tomography is performed immediately after surgery, the fibula may return to a good position 1 year after surgery. Level IV, case series.

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

To compare the accuracy of arthroscopic sagittal versus coronal plane distal tibiofibular motion toward diagnosing syndesmotic instability. 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. 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. Arthroscopic measurement of sagittal plane fibular translation is more accurate than coronal plane diastasis for evaluating syndesmotic instability. Clinicians should focus on distal tibiofibular motion in the sagittal plane when arthroscopically evaluating suspected syndesmotic instability. Biomechanical cadaveric study.

Biomechanics of the Distal Tibiofibular Syndesmosis: A Systematic Review of Cadaveric Studies.

Background:This investigation’s purpose was to perform a systematic review of the literature examining the biomechanics of the ligaments comprising the distal tibiofibular syndesmosis with specific attention to their resistance to translational and rotational forces. Although current syndesmosis repair techniques can achieve an anatomic reduction, they may not reapproximate native ankle biomechanics, resulting in loss of reduction, joint overconstraint, or lack of external rotation resistance. Armed with a contemporary understanding of individual ligament biomechanics, future operative strategies can target key stabilizing structure(s), translating to a repair better equipped to resist anatomic displacing forces.Study design:Systematic review.Methods:A systematic review was conducted according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines using a PRISMA checklist. Biomechanical studies testing cadaveric lower limb specimens in the intact and injured state measuring the distal tibiofibular syndesmosis resistance to translational and rotational forces were included in this review. Only studies that included numerical data were included in this review; studies that only reported figures and graphs were excluded.Results:Twelve studies met the inclusion and exclusion criteria. Two studies determined the mechanical properties of syndesmotic ligaments, finding superior strength and stiffness of the interosseous ligament (IOL), as compared to the anterior (AITFL) or posteroinferior tibiofibular ligament (PITFL). Four studies examined native ankle biomechanics establishing physiologic range of motion of the fibula relative to the tibia. Fibular range of motion was found to be up to 2.53 mm of posterior translation (Markolf et al), 1.00 mm lateral translation (Xenos et al), 3.6 degrees of external rotation (Burssens et al), and 1.4 degrees of internal rotation (Clanton et al). Four studies evaluated syndesmotic biomechanics under physiological loading and found that the AITFL, IOL, and PITFL provide the majority of resistance to external rotation, diastasis, and internal rotation, respectively. Two studies investigated the biomechanics of clinically and intraoperatively used tests for syndesmotic injuries and found increased sensitivity of sagittal plane posterior fibular translation, as opposed to coronal plane lateral fibular translation for unstable injuries.Conclusions:Study findings suggest that although the IOL is the strongest syndesmotic ligament, the AITFL has a dominant role stabilizing the distal tibiofibular syndesmosis to external rotation force. Because of these characteristics, operative repair of the AITFL along its native vector may provide a more biomechanically advantageous construct and should be investigated clinically. Additionally, evaluation of clinical stress tests revealed that the external rotation stress test is the most sensitive test to recognize an AITFL tear, and that a 3-ligament disruption is needed to cause diastasis greater than 2 mm.

Assessment of malreduction standards for the syndesmosis in bilateral CT scans of uninjured ankles.

Malreduction of the syndesmosis has been reported in up to 52% of patients after fixation of ankle fractures. Multiple radiological parameters are used to define malreduction; there has been limited investigation of the accuracy of these measurements in differentiating malreduction from inherent anatomical asymmetry. The purpose of this study was to identify the prevalence of positive malreduction standards within the syndesmosis of native, uninjured ankles. Three observers reviewed 213 bilateral lower limb CT scans of uninjured ankles. Multiple measurements were recorded on the axial CT 1 cm above the plafond: anterior syndesmotic distance; posterior syndesmotic distance; central syndesmotic distance; fibular rotation; and sagittal fibular translation. Previously studied malreduction standards were evaluated on bilateral CT, including differences in: anterior, central and posterior syndesmotic distance; mean syndesmotic distance; fibular rotation; sagittal translational distance; and syndesmotic area. Unilateral CT was used to compare the anterior to posterior syndesmotic distances. A difference of anterior to posterior syndesmotic distance > 2 mm was observed in 89% of ankles (n = 190) on unilateral CT assessment. Using bilateral CT, we found that 35% (n = 75) of normal ankles would be considered malreduced by current malreduction parameters. In 50 patients (23%), only one parameter was anomalous, 18 patients (8%) had two positive parameters and seven patients (3%) had three. Difference in fibular rotation had the lowest false positive rate of all parameters at 6%, whereas posterior syndesmotic distance difference had the highest at 15%. In this study, 35% of native, uninjured syndesmoses (n = 75) would be classified as malreduced by current diagnostic standards on bilateral CT and 89% had an asymmetric incisura on unilateral CT (n = 190). Current radiological parameters are insufficient to differentiate mild inherent anatomical asymmetry from malreduction of the syndesmosis. Cite this article: Bone Joint J 2021;103-B(1):178-183.

A New Method for Reduction and Stabilization of the Distal Tibiofibular Syndesmosis

Category:Ankle; TraumaIntroduction/Purpose:Fixation strategies for distal tibiofibular syndesmotic injuries are associated with risk of malreduction. We describe a new method of reduction and fixation of the syndesmosis with two suture buttons placed through a single sagittal tunnel through the fibula and across the tibia at the attachment sites of the anterior and posterior-inferior tibiofibular ligaments.Methods:Eighteen frozen cadaveric lower leg specimens were divided in two groups of nine and subjected to syndesmotic injury followed by reduction and fixation. Nine were repaired with the new method and 9 with the conventional method. Post-reduction CT images were obtained and compared to pre-injury CT images to assess quality of reduction. Specimens were then tested on an MTS machine and loaded between +\\-5Nm at 0.5Hz of internal and external rotation for 500 cycles. Cyclic loading was paused at 0, 100, and 500 cycles to assess torsional resistance, fibular rotation, and fibular translation with the foot first internally rotated 10 degrees and then externally rotated 15 degrees. Peak torque and translation of the fibula was measured.Results:A statistically significant difference was detected between groups, with the new method of fixation showing less lateral translation of the fibula. Data that did not reach statistical significance showed a trend towards decreased post reduction translation in the sagittal plane and improved rotational alignment with the new method. Decreased fibular rotation that reached statistical significance was noted in the new technique with internal rotation at 0, 100 and 500 cycles and during external rotation at 100 and 500 cycles. No differences were noted for torsional resistance or fibular translation between groups.Conclusion:The new method of syndesmotic fixation facilitated reduction of the syndesmosis that resulted in improved alignment, and better rotational stability compared with the conventional technique. This may be a reliable alternative to current methods of syndesmosis reduction and fixation.

Biomechanical Evaluation of a New Suture Button Technique for Reduction and Stabilization of the Distal Tibiofibular Syndesmosis.

Background:Stabilization methods for distal tibiofibular syndesmotic injuries present risk of malreduction. We compared reduction accuracy and biomechanical properties of a new syndesmotic reduction and stabilization technique using 2 suture buttons placed through a sagittal tunnel in the fibula and across the tibia just proximal to the incisura with those of the conventional method.Methods:Syndesmotic injury was created in 18 fresh-frozen cadaveric lower leg specimens. Nine ankles were repaired with the conventional method and 9 with the new technique. Reduction for the conventional method was performed using thumb pressure under direct visualization and for the new method by tightening both suture buttons passed through the fibular and tibial tunnels. Computed tomography was used to assess reduction accuracy. Torsional resistance, fibular rotation, and fibular translation were evaluated during biomechanical testing.Results:The new technique showed less lateral translation of the fibula on CT measurements after reduction (0.06 ± 0.06 mm) than the conventional method (0.26 ± 0.31 mm), P = .02. The new technique produced less fibular rotation during internal rotation after 0 cycles (new –2.4 ± 1.4 degrees; conventional –5.0 ± 1.2 degrees, P = .001), 100 cycles (new –2.1 ± 1.9 degrees; conventional –4.6 ± 1.4 degrees, P = .01), and 500 cycles (new –2.2 ± 1.6 degrees; conventional –5.3 ± 2.5 degrees, P = .01) and during external rotation after 100 cycles (new 3.9 ± 3.3 degrees; conventional 5.9 ± 3.5 degrees, P = .02) and 500 cycles (new 3.3 ± 3.2 degrees; conventional 6.3 ± 2.6 degrees, P = .03). Fixation failed in 3 specimens.Conclusion:The new syndesmotic reduction and fixation technique resulted in more accurate reduction of the fibula in the tibial incisura in the coronal plane and better rotational stability compared with the conventional method.Clinical Relevance:This new technique of syndesmosis reduction and stabilization may be a reliable alternative to current methods.

Using Portable Ultrasound to Measure the Effect of Lateral Ankle Ligament Injury on Syndesmotic Stability: A Cadaveric Study

Category:Ankle; Sports; TraumaIntroduction/Purpose:About one-fifth of all patients diagnosed with an ankle sprain also suffer a ligamentous injury of the ankle syndesmosis. Despite the common concomitant injuries, it is still unclear whether there is a direct contribution of the lateral ligaments towards stabilizing the syndesmosis. Portable ultrasonography (PUS) has increasingly been used in the clinical setting, allowing dynamic and non-invasive evaluation at the point of care. The primary aim of this study was to assess to what extent lateral ankle ligaments contribute to syndesmotic stability in the sagittal and rotational plane using PUS. Secondary, we determine if PUS is a reliable tool for the assessment of syndesmotic instability. Our primary hypothesis was that lateral ankle ligaments contribute significantly to the stability of the ankle syndesmosis.Methods:16 fresh-frozen cadaveric specimens were equally divided into 2 groups that underwent PUS evaluation for syndesmotic stability. The assessment was done at the intact state and later with sequential ligament transection. In group 1, the anterior talofibular ligament (ATFL) was transected, followed by the calcaneofibular ligament (CFL), the posterior talofibular ligament (PTFL), the anteroinferior tibiofibular ligament (AITFL), the interosseous ligament (IOL), and the posteroinferior tibiofibular ligament (PITFL). In group 2, the transection started with the AITFL then followed by the ATFL, the CFL, the IOL, the PTFL, and the PITFL. PUS measurements were performed during anterior to posterior (AP), posterior to anterior (PA), and external rotated loading condition (Figure 1). One-way ANOVA and post hoc Dunnett test were used to compare the findings of each state to the intact. Besides, we assessed the inter-rater and intra-rater reliability using the intraclass correlation coefficient (ICC) through a two-way mixed-effects model.Results:In group 1, showed that compared to the intact stage, fibular translation in the sagittal plane and the anterior tibiofibular clear space (TFCS) distance did not increase after transection of all three lateral ankle ligaments. However, the syndesmotic PUS measurements did increase after subsequent transection of the AITFL and IOL (p-values ranging from 0.047 to <0.001). In group 2, the AP translation of the fibula in sagittal plane, as well as the anterior TFCS distance, only increased significantly after transection of at least two syndesmotic ligaments (AITFL, IOL) together with two lateral ligaments (ATFL and CFL) (p-values ranging from 0.047 to <0.001). The ICCs Inter-rater and intra-rater reliability for syndesmotic PUS measurements ranged from 0.84-0.95, indicating excellent agreement.Conclusion:PUS is a reliable tool for the assessment of syndesmotic instability. Using PUS we found that lateral ankle ligaments contribute marginally to the stability of the ankle syndesmosis. Syndesmotic sagittal and rotational plane instability occurred after injury to all three syndesmotic ligaments or after partial syndesmotic injury (AITFL+IOL) with concomitant two or more lateral ankle ligament injury. The intraclass correlation coefficient for the sagittal and rotational plane assessment of syndesmosis using PUS indicated excellent inter- and intraobserver agreement, and thus, can be a valuable diagnostic tool at the point of care.

Diagnosing syndesmotic instability with dynamic ultrasound – establishing the natural variations in normal motion

BackgroundSyndesmotic instability, when subtle, is challenging to diagnose and often requires visualization of the syndesmosis during applied stress. The primary aim was to assess normal distal tibiofibular motion in the sagittal plane using dynamic ultrasound under stress conditions. The secondary aim was to evaluate the reliability of dynamic stress ultrasonography. MethodsTwenty-eight participants without history of ankle injury were included. Sagittal fibular translation was generated by applying a manual force to the fibula from anterior to posterior and from posterior to anterior. Distance between the ultrasound probe and the fibula was taken at two predefined points: 1) no force applied and, 2) during maximum force application. Each participant was scanned twice by two independent examiners, and each scan was analysed by two independent examiners. Three participants were scanned a second time by the same examiner who analysed these films twice to assess for intraobserver agreement. Means of exam 1 versus exam 2 were compared using a mixed linear model. Agreement among observers was calculated using intraclass correlation coefficients (ICC) interpreted as 0.4, poor; 0.4 〈 ICC < 0.59, acceptable; 0.6 < ICC < 0.74, good; ICC 〉 0.74, excellent. ResultsFifty-six ankles were included in the study, including 16 (57%) males and 12 (42%) females. Average anterior to posterior fibular sagittal translation was 0.89 ± 0.6 mm and posterior to anterior fibular sagittal translation was 0.49 ± 1.1 mm. Anterior to posterior translation means of exam 1 versus exam 2 showed no significant differences, means of 0.81 mm [0.7–0.9] versus 0.77 mm [0.7–1.0], and posterior to anterior means [95% CI] of 0.42 mm [0.3–0.5] versus 0.44 mm [0.2–0.6] (p-values 0.416 and 0.758, respectively). Excellent Inter- and intraobserver agreement was found for all measurements taken. ConclusionDynamic ultrasound allows one to effectively and readily evaluate sagittal translation of the distal tibiofibular joint. It is able to afford bilateral comparisons, which becomes critical as the amount of syndesmotic instability approaches greater degrees of subtlety.

Does Intramedullary Nailing for Distal Fibular Fractures Restore Anatomic Parameters and Syndesmotic Relationship?

Category:Trauma; AnkleIntroduction/Purpose:Fibular nailing (FN) is a method of fixation that has proven to be useful for the treatment of distal fibular fractures (DF). FN minimizes soft tissue complications, provides similar stability compared to plating with less hardware related symptoms. Nevertheless, FN has been associated with syndesmotic malreduction and incapacity of restoring length and rotation of the fibula. We aimed to evaluate the fibular and syndesmotic reduction after fixation with FN compared to the uninjured ankle.Methods:Prospective cohort, cross-sectional study with a paired control group. Patients with DF fractures treated with FN between January 2017 and July 2019 were included. Immediate postoperative bilateral Ankle CT was obtained in all cases. Two independent radiologists performed all the measurements on both ankles (fibular rotation, length, translation, and syndesmotic diastasis. Statistical analysis was made using the Wilcoxon Test and Intraclass correlation coefficient (ICC). Considering a medium size sample effect, 95% confidence with .05 alpha error, a total sample of 26 subjects were needed to achieve a .80 of statistical power (G-Power 3.1). All analyses were performed using SPSS V20.Results:Twenty-six patients were included (14 Women). The mean age was 47 years (18-91). No statistically significant differences were identified considering fibular rotation (p:0,694), fibular length (p:0,585) and syndesmotic diastasis (p:0,078) between the injured and uninjured ankle. Fibular translation has statistical differences (p:0,043). The ICC shows an excellent concordance between radiologists except for Fibular translation (ICC 0,47)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.

Screw Versus Suture Button in Treatment of Syndesmosis Instability: Clinical and Radiographic Outcomes Using PROMIS and Weight Bearing CT Scan

Category:Trauma; Ankle; SportsIntroduction/Purpose:Traumatic injuries to the distal tibiofibular syndesmosis are relatively common and can be associated with ankle fractures or occur as purely ligamentous injuries. Unstable syndesmotic injuries require surgical repair, generally performed using either screw or suture button fixation. The superiority of either fixation method remains a subject of ongoing debate. The aim of this study is to compare both clinical and radiographic outcomes of screw and suture button fixation of syndesmosis instability using Patient-Reported Outcomes Measurement Information System (PROMIS) and weight bearing CT scan (WBCT).Methods:Medical records were reviewed to identify patients who had a unilateral syndesmotic injury requiring surgical stabilization and who were at least one year out from injury. Exclusion criteria included patients less than 18 years old, ipsilateral pilon fracture, history of contralateral ankle or pilon fracture or syndesmosis injury, BMI >40, and any neurological impairment. Twenty eligible patients were recruited to complete PROMIS questionnaires and undergo bilateral WBCT scan of both ankles, divided into two groups. In the first group (n=10) the patients had undergone screw fixation of the syndesmosis, while in the second group (n=10) the syndesmosis was fixed using a suture button construct. All patients completed PROMIS questionnaires for pain intensity, pain interference, physical function and depression. Radiographic assessment was performed using axial images of WBCT scan of both the injured ankle and the contralateral normal side at a level one cm proximal to the tibial plafond (Figure 1).Results:At an average follow up of three years, none of the recruited patients required a revision surgery. There was no significant difference between the two groups in terms of the four PROMIS questionnaires (P values ranged from 0.17 to 0.43). In the suture button group, the measurements of the injured side were significantly different from the normal side for the syndesmotic area (P=0.003), fibular rotation (P=0.004), anterior difference (P=0.025) and direct anterior difference (P=0.035).Other measurements of posterior difference, middle difference, direct posterior difference and fibular translation were not significantly different (P values ranged from 0.36 to 0.99). In the screw fixation group, the syndesmotic area was the only significantly different measurement in the injured side as compared to the normal side (P=0.006).Conclusion:Screw and suture button fixation for syndesmotic instability have similar clinical outcomes at average three years follow up as measured by PROMIS scores. Both screw and suture button did not entirely restore the syndesmotic area as compared to the contralateral normal ankle, suggesting some residual diastasis on weight bearing CT. In addition, as compared to screw fixation, the suture button did not seem to restore the normal fibular rotation, with residual external rotation of the fibula noted. Longer clinical follow up is necessary to understand the clinical implication of such malreduction.

Sagittal instability with inversion is important to evaluate after syndesmosis injury and repair: a cadaveric robotic study

PurposeDisruption of the syndesmosis, the anterior-inferior tibiofibular ligament (AITFL), the posterior-inferior tibiofibular ligament (PITFL), and the interosseous membrane (IOM), leads to residual symptoms after an ankle injury. The objective of this study was to quantify tibiofibular joint motion with isolated AITFL- and complete syndesmotic injury and with syndesmotic screw vs. suture button repair compared to the intact ankle.MethodsNine fresh-frozen human cadaveric specimens (mean age 60 yrs.; range 38–73 yrs.) were tested using a six degree-of-freedom robotic testing system and three-dimensional tibiofibular motion was quantified using an optical tracking system. A 5 Nm inversion moment was applied to the ankle at 0°, 15°, and 30° plantarflexion, and 10° dorsiflexion. Outcome measures included fibular medial-lateral translation, anterior-posterior translation, and external rotation in each ankle state: 1) intact ankle, 2) AITFL transected (isolated AITFL injury), 3) AITFL, PITFL, and IOM transected (complete injury), 4) tricortical screw fixation, and 5) suture button repair.ResultsBoth isolated AITFL and complete injury caused significant increases in fibular posterior translation at 15° and 30° plantarflexion compared to the intact ankle (p < 0.05). Tricortical screw fixation restored the intact ankle tibiofibular kinematics in all planes. Suture button repair resulted in 3.7 mm, 3.8 mm, and 2.9 mm more posterior translation of the fibula compared to the intact ankle at 30° and 15° plantarflexion and 0° flexion, respectively (p < 0.05).ConclusionAnkle instability is similar after both isolated AITFL and complete syndesmosis injury and persists after suture button fixation in the sagittal plane in response an inversion stress. Sagittal instability with ankle inversion should be considered when treating patients with isolated AITFL syndesmosis injuries and after suture button fixation.Level of evidenceControlled laboratory study, Level V.

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

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. 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. 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%). 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. These data can help surgeons arthroscopically distinguish between stable syndesmotic injuries and unstable ones that require syndesmotic stabilization.