The effect of suture-button fixation on simulated syndesmotic malreduction: a cadaveric study

A 3-Ligament Syndesmotic Injury Is at Higher Risk for Malreduction Than a 2-Ligament Injury: A CT-Based Analysis

BACKGROUND

Syndesmotic malreduction is common and has been associated to an impaired outcome. Various risk factors for DTFJ malreduction have been postulated. The aims of this study were to assess the DTFJ malreduction rate based on (1) the severity of the syndesmotic injury, (2) the anatomy of the tibial incisura, and (3) the fixation device used in patients treated with suture-button systems.

METHODS

This retrospective, radiographic study included all adult patients who were treated for an acute, unilateral, and unstable syndesmotic injury with a suture-button system and postoperative bilateral CT imaging. Included were isolated syndesmotic injuries and fracture cases. The number of syndesmotic ligaments injured, that is, 2-ligament (AiTFL+IOL) and 3-ligament (AiTFL+IOL+PiTFL), was rated for each patient. The quality of DTFJ reduction, as well as the anatomy of the tibial incisura, was rated based on the postoperative, bilateral CT images and the intraoperative DTFJ reduction was recalculated based on the drilling-tunnel deviation. The possible influence on the DTFJ malreduction rate was assessed.

RESULTS

A total of 147 patients were included, and 94 and 53 patients had a 2- and 3-ligament syndesmotic injury, respectively. In addition, 113 patients were treated with a single-button system, 26 with a double suture-button system, and 8 with a hybrid fixation (suture-button + screw). Malreduction was significantly higher in 3-ligament compared with 2-ligament injuries, both intraoperatively (51% vs 27%; P = .003) and postoperatively (28% vs 11%; P = .006). The tibial anatomy had no significant influence on the malreduction rates. No significant differences were seen per the different fixation devices used independent of the number of ligaments injured.

CONCLUSION

This study did not find an influence of the incisura's anatomy on the DTFJ malreduction rate. However, we did find that 3-ligament syndesmotic injuries carried a higher risk of intra- and postoperative malreduction compared with 2-ligament injuries.

LEVEL OF EVIDENCE

Level III, retrospective radiologic study.

Effect of Distal Tibiofibular Destabilization and Syndesmosis Compression on the Flexibility Kinematics of the Ankle Bones: An In Vitro Human Cadaveric Model

Background

Overcompression of the distal tibiofibular syndesmosis during open reduction and internal fixation of ankle fracture may affect multidirectional flexibility of the ankle bones.

Methods

Ten cadaveric lower limbs (78.3±13.0 years, 4 female, 6 male) underwent biomechanical testing in sagittal, coronal, and axial rotation with degrees of motion quantified. The intact force (100%) was the force needed to compress the syndesmosis just beyond the intact position, and overcompression was defined as 150% of the intact force. After intact testing, the anterior inferior tibiofibular ligament (AITFL), interosseus membrane (IOM), and posterior inferior tibiofibular ligament (PITFL) were sectioned and testing was repeated. The IOM and AITFL were reconstructed in sequence and tested at 100% and 150% compression.

Results

Overcompression of the syndesmosis did not significantly reduce ROM of the ankle bones for any loading modality (P > .05). IOM+AITFL reconstruction restored distal tibiofibular axial rotation to the intact condition. Axial rotation motion was significantly lower with AITFL fixation compared with IOM fixation alone (P < .05). The proximal tibiofibular syndesmosis demonstrated significantly higher motion in axial rotation with all distal reconstruction conditions.

Conclusion

As assessed by direct visualization, overcompression of the distal tibiofibular syndesmosis did not reduce ROM of the ankle bones. Distal tibiofibular axial rotation was significantly lower with IOM+AITFL fixation compared with IOM augmentation alone. Distal tibiofibular axial rotation did not differ significantly from the intact condition after combined IOM+AITFL fixation. Dynamic fixation of the distal tibiofibular syndesmosis resulted in increased axial rotation at the proximal tibiofibular syndesmosis.

Clinical Relevance

These biomechanical data suggest that inadvertent overcompression of the distal tibiofibular syndesmosis when fixing ankle fractures does not restrict subsequent ankle bone ROM. The AITFL is an important stabilizer of the distal tibiofibular syndesmosis in external rotation.

Level of Evidence

controlled laboratory study.

The Center-Center Image Closely Approximates Other Methods for Syndesmosis Reduction Clamp Placement

BACKGROUND

The optimal placement for a syndesmosis reduction clamp remains an open question. This study compared the center-center axis, which localizes clamp placement using only an internally rotated lateral ankle X-ray, with other common approaches, whose accuracy can only be confirmed using computed tomography (CT).

METHODS

Bone models of anatomically aligned (n = 6) and malreduced (n = 48) limbs were generated from CT scans of cadaveric specimens. Four axes for guiding clamp placement (center-center, centroid, B2, and trans-syndesmotic) were then analyzed, using digitally reconstructed radiographs derived from the bone models. Each axis' location was defined using angle-height pairs that describe axis orientation along the full anatomical region where syndesmosis fixation occurs.

RESULTS

In anatomically aligned limbs, the center-center axis was located on average (±95% CI [confidence interval]), 0.64° (±0.50°) internal rotation, 1.03° (±0.73°) internal rotation, and 2.09° (±7.29°) external rotation from the centroid, B2, and trans-syndesmotic axes, respectively. Fibular displacement altered the magnitude of limb rotation needed to identify the center-center axis.

CONCLUSION

The center-center technique is a valid method that closely approximates previously described methods for syndesmosis clamp placement without using CT, and the magnitude of C-arm rotation needed to transition from a talar dome lateral to a center-center view may be a potential method for assessing syndesmosis reduction.

LEVELS OF EVIDENCE

Level III: Retrospective comparative study.

Maisonneuve fracture treated with suture-button system stabilization combined with plate and arthroscopic assistance (SBPAA): Clinical and radiological evaluation in short-medium period

The aim of this study was to estimate the time needed for patients with Maisonneuve fractures to return to routine activities, after treatment with a suture-button system stabilization combined with plate and arthroscopic assistance (SBPAA).

Methods

The study included 13 patients treated at our surgical department from January 2018 to June2022. Specific radiographical follow-up and periodic checks were performed in a short -to-medium term period, to evaluate syndesmosis evolution and tibiofibular overlap with medial clear space (MCS).

Results

Progressive recovery and improvement were observed during follow-up from both radiographic and clinical perspective. Data showed that patients were able to return to full weight-bearing walking around the ninth week and to sport activities in 7.5 months. Long-term complications associated with residual joint stiffness, complex regional pain syndrome, or wound complications were observed in three patients.

Conclusions

Intraoperative arthroscopy represent a valid diagnostic tool to better recognize and evaluate osteochondral lesions in case of syndesmosys. The study demonstrates the importance of intraoperative arthroscopy for recognizing and treating associated osteochondral lesions with proper syndesmosis evaluation. Plate associated to double TightRope represent valid solution to functionally fix and reduce fractures. Additionally, it imitates the normal syndesmosis's anatomy and provides elasticity and robustness, guaranteeing a rapid return to sporting activity. Data and casuistry support these findings.

Validity of the Center-Center Method for the Syndesmotic Fixation Axis Compared to the Transsyndesmotic Axis

BACKGROUND

Placement of clamp forceps along the transsyndesmotic (TS) axis reduces the risk of iatrogenic syndesmotic malreduction during ankle fracture surgery with tibiofibular diastasis. This study aimed to measure the difference between the TS axis and the axis determined by an intraoperative fluoroscopic technique using the center-center (CC) method. We also compared the values obtained when the CC method was performed at different heights from the tibial plafond.

METHODS

We evaluated the computed tomography scans of 150 patients with normal syndesmosis. The CC method was simulated using digitally reconstructed radiographs. The TS and CC axes were projected onto an axial computed tomographic image linked to digitally reconstructed radiography. The angle between the two axes (interaxis angle) and the distance between the intersection of these axes and the medial tibial cortex (interaxis distance) were measured. The procedures were performed 0, 10, and 20 mm proximal to the tibial plafond, and the measurements were compared among the different heights using a 1-way repeated-measures analysis of variance.

RESULTS

The TS axis was found to be externally rotated to the CC axis, with an interaxis angle of 8.5 degrees (SD, 6.8 degrees). The interaxis angle increased from 1.9 degrees at a height of 0 mm to a greater angle at higher heights (P < .001). The overall interaxis distance was 7.7 (SD, 6.3) mm, increasing from 2.0 mm at a height of 0 mm to a greater distance at higher heights (P < .001).

CONCLUSION

The TS axis was externally rotated relative to the CC axis, and the difference between the 2 axes was greater when the CC method was performed on the higher heights from the tibial plafond. To clamp the syndesmosis along the TS axis, the CC method should be applied close to the ankle joint.

LEVEL OF EVIDENCE

Level IV, case series.

Current concepts in ankle fractures

Ankle fractures are among the most common orthopaedic injuries. Operative management is performed in unstable ankle fracture patterns to restore the stability and native kinematics of the ankle mortise and minimize the risk of post-traumatic degenerative changes. In this study, we review current concepts in ankle fracture management, including posterior malleolus fixation, syndesmosis fixation, deltoid ligament repair, fibular nailing, and early weightbearing, from both a biomechanical and clinical perspective.

Dynamic syndesmotic stabilisation and reinforcement of the antero-inferior tibiofibular ligament with internal brace

PURPOSE

Syndesmotic injuries are associated with long recovery times and high morbidity. Systematic reviews show a trend toward better outcomes of suture buttons compared to screw fixation. The anteroinferior tibiofibular ligament (AITFL) confers the most significant component of translational and rotatory stability. Techniques have developed which reinforce the AITFL. This study aimed to assess results of syndesmotic stabilisation with dynamic stabilisation and reinforcement of the AITFL, with an early mobilisation program.

MATERIALS AND METHODS

Retrospective case series of 30 patients (mean age 31 years). Syndesmotic instability was confirmed with clinical examination, MRI and weightbearing-CT. Dynamic syndesmotic stabilisation with a single suture button was performed followed by the placement of an Internal Brace over the AITFL. A standardised postoperative rehabilitation protocol was established. Foot and Ankle Ability Measure (FAAM) scores were collected postoperatively.

RESULTS

The average follow-up was 13 months. The total FAAM score for ADL was 95 ± 4.9 % (range, 83 - 100 %) and for sport activities 87 ± 13.6 % (range, 50 - 100 %). The rating of mean postoperative function for ADL was 94 ± 5.5 % (range, 80 - 100 %) and 90 ± 13 % (range, 35 - 100 %) for sportv. The difference between acute and chronic injuries was statistically higher (p < 0.05) for daily activities and sport, but the rating of current level of sport activites as well as for daily activites did not show a significant difference (p = 0.9296 and p = 0.1615, respectively). Twenty-seven patients (90 %) rated their overall current level of function as normal or nearly normal.

CONCLUSION

This technique aims to directly stabilise the AITFL and the interosseous components of the syndesmosis, and allow early mobilisation and return to sport at 10 weeks. Early results show the procedure is safe, with comparable results to the literature. Acute injuries showed better results of the FAAM score than chronic injuries.

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.

“Flexible nature of fixation” in syndesmotic stabilization of the inferior tibiofibular joint affects the radiological reduction outcome

Purpose

Fibular mobility after suture button stabilization (SBS) of inferior tibiofibular joint (syndesmosis) injuries has been described. This effect is called the “flexible nature of fixation (FNF).” In this study, we aimed to quantify FNF in syndesmotic stabilization.

Methods

Postoperative bilateral computed tomography (CT) of ankle fractures with syndesmosis stabilization by SBS or syndesmotic screw (SYS) was retrospectively analyzed. The transverse offset (TO) and vertical offset (VO) were defined by evaluating the drill channels. The reduction outcome was evaluated by the side-to-side difference between the clear space and the anterior tibiofibular distance (antTFD). The calculated anterior tibiofibular distance (cal-antTFD) was calculated by subtracting the TO from the validated antTFD. Subsequently, a reevaluation of the reduction outcomes after SYS or SBS stabilization was performed using cal-antTFD.

Results

Sixty patients (44 with SBS and 16 with SYS stabilization) were analyzed. The intra-rater and inter-rater reliabilities for TO and VO were excellent (α > 0.92). SYS stabilization showed lower mean TO (− 0.02 mm; SD 0.14) and VO (0.11 mm; SD, 0.29 mm) than SBS stabilization (TO 1.16 mm, SD 1.4 mm; VO 0.2 mm, SD 0.8 mm; p = 0.001). The rate of malreduction according to cal-antTFD was higher than that of antFTD (p = 0.033).

Conclusion

The presented method, which evaluates the position of the tibial to the fibular drill channel, allowed the quantification of the “FNF.” The often described difference in the dynamic stabilization of SBS compared to the rigid stabilization by SYS could be objectified. Considering cal-antTFD illustrates that FNF potentially reduces the rate of malreduction in SBS stabilization.

A Novel Adjustable EndoButton Fixation Assisted by 3D Printing Technology for Tibiofibular Syndesmosis Injury: A Biomechanical Study

Purpose: The recommendations for surgical fixation of tibiofibular syndesmosis injuries are increasingly challenging for many clinical orthopedists, as international consensus has not been published for the optimal treatment of the injury. Thus, we have created a 3D-printed navigation template for a precise bone tunnel and a novel adjustable EndoButton fixation (NAE) for the ideal treatment. The purpose of this research was to evaluate the accuracy of the 3D-printed navigation template and explore the biomechanical performance of the NAE technique by comparing it with the intact syndesmosis, screw technique, and TightRope (TR) technique.

Methods: Twenty-four human cadaveric legs were randomly allocated to four groups: the NAE group (n = 6), TR group (n = 6), screw group (n = 6), and intact group (n = 6). A personalized navigation template based on computed tomography scans was designed, and 3D printing models were generated for the distal tibiofibular syndesmosis. The NAE, TR, and screw group were performed via 3D-printed navigation template, respectively. All groups were tested under increasing loading forces including axial loading (from 100 N to 700 N) and torsional loading (from 1 N to 5 N), which were performed in different ankle positions. The displacements of the tibiofibular syndesmosis were analyzed using the Bose Electroforce 3510-AT biomechanical testing equipment.

Results: Surgical fixations were conducted successfully through a 3D-printed navigation template. Both in axial or torsional loading experiments, no statistically significant difference was observed in the displacements among the NAE, TR, and intact groups in most situations (p &gt; 0.05), whereas the screw group demonstrated obviously smaller displacements than the abovementioned three groups (p &lt; 0.05).

Conclusion: The 3D printing technology application may become beneficial and favorable for locating and making the bone tunnel. Also, the NAE fixation provides the performance of complete ligaments; it also restores physiologic micromotion and avoids insufficient or excessive reduction when compared to the TR and screw technique. This may offer a new fixation for the treatment of tibiofibular syndesmosis injuries that is desirable for clinical promotion.

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.

Does the orientation of syndesmosis fixative device affect the immediate reduction of the distal tibiofibular joint?

INTRODUCTION

Incongruent stabilization of the distal tibiofibular joint (syndesmosis) results in poorer long-term outcome in malleolar fractures. The aim was to analyze whether the orientation of the syndesmotic stabilization would affect the immediate reduction imaged in computed tomography (CT).

MATERIALS AND METHODS

The syndesmotic congruity in 114 ankle fractures with stabilization of the syndesmosis were retrospectively analyzed in the post-operative bilateral CT scans. The incisura device angle (IDA) was defined and correlated with the side-to-side difference of Leporjärvi clear-space (ΔLCS), anterior tibiofibular distance (ΔantTFD) and Nault talar dome angle (ΔNTDA) regardless of the stabilization technique and separately for suture button system and syndesmotic screw. Asymmetric reduction was defined as ΔLCS > 2 mm and |ΔantTFD|> 2 mm.

RESULTS

Regardless of the stabilization technique, no correlation between the IDA and the ΔLCS (r = 0.069), the ΔantTFD (r = 0.019) nor the ΔNTDA (r = 0.177) could be observed. There were no differences between suture button system and syndesmotic screw. Asymmetrical reduction was detected in 46% of the cases, while sagittal asymmetry was most common. No association was found between the orientation of stabilization device and occurrence of asymmetrical reduction (p > 0.05). The results of suture button system and syndesmotic screw were comparable in this respect (p > 0.05).

CONCLUSION

Poor correlation between the orientation of the stabilization device and the immediate post-operative congruity of the syndesmosis could be shown. In contrast to current literature, this study did not show difference of suture button system over syndesmotic screw in this regard. Careful adjustment of the fibula in anteroposterior orientation should be given special attention.

The Syndesmosis, Part II: Surgical Treatment Strategies

Syndesmotic injuries in the setting of ankle fracture are critically important to diagnosis and treat to restore an anatomic tibiotalar relationship. Physical examination and clinical suspicion remain critically important for diagnosis. Ultrasound examination and weight-bearing computed tomography scans are evolving to help diagnosis more subtle injuries. Although flexible syndesmotic fixation may decrease malreduction rates, the benefits over rigid fixation is the subject of ongoing study. Anatomic reduction remains critical regardless of fixation choice. Routine removal of rigid syndesmotic hardware does not seem to offer substantial clinical improvement in pain or range of motion; however, broken hardware may cause irritation.

Syndesmotic Stabilization: Syndesmotic Screw Versus Flexible Fixation: A Systematic Review

Syndesmotic injuries are common injuries that occur in isolation or associated with ankle fractures. The suture button device fixation (SBDF) has become increasingly attractive to orthopedic surgeons as an alternative to metallic screw fixation (MSF) for syndesmotic fixation. This review involved the highest-quality clinical biomechanical and cost analysis studies to provide a comprehensive review. A literature search in the electronic databases was conducted to identify clinical, biomechanical as well as cost analysis studies in which the MSF was compared to SBDF from 1990 to 2018. Only comparative clinical studies with a level of evidence I or II were included besides any comparative biomechanical or cost analysis study. The (PRISMA) guidelines were followed. Eight clinical, 11 biomechanical, and 3 cost analysis studies were included. The clinical studies consisted of 5 randomized controlled trials (RCTs) and 3 cohort studies. The average American Orthopaedic Foot and Ankle Society score for the SBDF group was (92.4) compared to (86.6) for the MSF group at 1 year follow-up. SBDF group showed a lower rate of malreduction, implant removal, implant failure, and complications. The biomechanical studies showed better reduction accuracy in the SBDF group. The reduction maintenance was comparable in the coronal plane but not in the sagittal plane. The cost-effectiveness of the SBDF was highly dependent on the difference in implant removal rate. In conclusion, the SBDF showed comparable to better outcomes compared to the MSF. It may be a better option for syndesmotic fixation.

Biomechanical evaluation of syndesmotic fixation techniques via finite element analysis: Screw vs. suture button

BACKGROUND AND OBJECTIVE

Tibiofibular syndesmotic injuries may cause degenerative changes, reduction in ankle function and compromising ankle stability. Different fixation techniques try to restore its functionality. Screw-fixation is the gold-standard. Recently, suture-button fixation has aroused the attention because it allows for physiologic micromotion while maintaining an accurate reduction. The aim of this study is to compare the biomechanical behaviour of both fixation techniques using the finite element method.

METHODS

A three-dimensional finite element model of the tibiofibular joint was reconstructed simulating the intact ankle and the injured syndesmosis. Then, different methods of syndesmosis fixation were analysed: screws (number of cortices, number of screws and distance between screws) and suture buttons (single, double parallel and double divergent with a sensitivity analysis on the pretension forces) configuration. Ligaments and cartilages were included and simulated as spring elements. Physiological loads during stance phase were simulated.

RESULTS

Syndesmosis widening and von Mises stresses were computed. Syndesmosis widening in the injured configuration compromised joint stability (2.06 mm), whereas using a single quadricortical screw (0.18 mm) stiffened the joint. Syndesmosis widening using suture-buttons were closer to syndesmosis widening of the intact ankle configuration (0.97 mm). Von Mises stresses were higher for the titanium screws than for the suture buttons.

CONCLUSIONS

A detailed biomechanical comparison among different syndesmotic fixation was performed. Suture buttons have advantages with regard to syndesmosis widening in comparison to screw fixation. This fact supports the good long-term clinical results obtained with suture buttons fixation. The proposed methodology could be an efficient tool for preoperative planning.

The Impact of Suture Button Removal in Syndesmosis Fixation

The suture button (SB) device was introduced to negate the need for routine hardware removal in the treatment of syndesmosis injuries. However, a considerable SB removal rate has been reported, and the impact of removal is unknown. This study aimed to evaluate the radiographic and clinical outcomes after removal of SB for syndesmosis fixation. A total of 36 patients who underwent removal surgery after syndesmosis fixation using SB were identified. The mean postoperative time to removal was 12.2 months. On a plain radiograph, tibiofibular clear space (TFCS) was measured and compared at three follow-up time points. In patients with computed tomography (CT) imaging (n = 18), the anterior-to-posterior (A/P) ratio was measured to evaluate changes in quality of reduction. Additionally, clinical outcomes were assessed. There were no significant differences in TFCS between the three follow-up periods. None of the patients exhibited recurrent diastasis after SB removal. Although CT analysis demonstrated malreduction in six patients (33.3%), five of six patients had a subsequent spontaneous reduction of the syndesmosis. Clinically, all patients described the resolution of symptoms related to painful hardware at the final follow-up. Our results demonstrate that SB removal at one year following syndesmosis fixation leads to improved clinical symptoms without negatively impacting the quality of syndesmosis reduction.

Dual Suture Button Fixation With Buttress Plate for Ankle Syndesmotic Injury

SUMMARY

In this video, we present a unique approach to a purely ligamentous syndesmotic injury in a 16-year-old football player. Syndesmotic reduction was obtained using a large clamp and validated by matching fibular position to a fluoroscopic image of the contralateral ankle. Fixation was achieved using dual suture button devices in combination with a buttress plate. A small medial incision was used to protect the saphenous neurovascular bundle during button placement.

Suture-button Versus Screw Fixation in Adolescent Syndesmotic Injuries: Functional Outcomes and Maintenance of Reduction

BACKGROUND

Fixation of the tibiofibular syndesmosis is often performed with a trans-syndesmotic screw (SS) or suture-button (SB). SB fixation has been shown to have lower rates of postoperative syndesmotic malreduction, late diastasis, and implant removal, though some studies have found complications related to infection and implant subsidence. The purpose of this study was to compare maintenance of reduction, complications, implant removal and functional outcomes of SB versus SS fixation in adolescents.

METHODS

A retrospective chart review identified patients who underwent syndesmotic fixation from 2010 to 2019 at a single institution. Loss of syndesmotic reduction (diastasis) was defined as either a >2 mm increase in tibiofibular clear space or >2 mm decrease in tibiofibular overlap, and corresponding incongruence of the ankle mortise (medial clear space 1 millimeter greater than superior clear space). Functional outcomes were collected at a minimum of 1 year postsurgery using the Foot and Ankle Ability Measure (FAAM).

RESULTS

Seventy-seven adolescents (45 SS, 32 SB) were included (mean age: 16±1.5 y). Forty-five patients had Weber C fibula fractures, 27 Weber B fractures, and 5 had isolated syndesmotic injuries or small posterior malleolus fractures. Fifty-one patients (66%) had functional outcomes available. There was no significant difference in mean FAAM Sports score between the 2 groups (SB=94.8%, SS=89.8%) at mean follow-up of 4.0±2.1 years. Syndesmotic implant removal occurred in 36/45 patients (80%) in the SS group compared with 4/32 patients (13%) in the SB group. There was 1 case of syndesmotic malreduction requiring revision surgery in the SS group, and no cases of postoperative malreduction or diastasis in the SB group. Nine patients in the SB group and 8 in the SS group weighed over 100 kilograms, with no cases of diastasis in these larger patients. There were 4 superficial infections and 1 deep infection in the screw group, with 1 superficial infection in the SB group.

CONCLUSIONS

While both SB and screw fixation maintained syndesmotic reduction, SB fixation led to lower rates of implant removal surgery. SB fixation was equally effective at preventing recurrent diastasis in adolescents weighing over 100 kilograms, and functional outcomes were at least equivalent to screw-fixation at mean follow-up of 4.0 years.

LEVEL OF EVIDENCE

Level III.

Implications of the Overlapping Degree Between Proximal Fibula and Tibia for Placing the Optimal Syndesmotic Screw: A Virtual Cadaveric Study

BACKGROUND

To determine the optimal direction of the syndesmotic screw and to introduce a consistent landmark for practical application by analyzing three-dimensional (3D) modeling and virtual implantation.

METHODS

A total of 105 cadaveric lower legs (50 males and 55 females; average height, 160.6 ± 7.1 cm) were used to reconstruct a 3D model by using the Mimics® software and the joint morphology was evaluated. Syndesmotic cylinders (Ø3.5 mm/Length 100 mm) were transversely placed in the proximal end of the incisura fibularis for simulating screw fixation. The tibial proximal cylinder, which was tangent to the posterior tibial condyles, was traced and the angle between the two cylinders was measured as the tibial torsion angle (TTA). After rotating the syndesmotic cylinder parallel to the ground, the overlapping degree between the proximal fibula and tibia was assessed as a radiologic indicator.

RESULTS

Concerning tibial torsion, the TTA was an average of 36.7° (range, 17.2°-54.4°; SD, 8.78) When the syndesmotic cylinder was rotated to be parallel to the ground, the proximal fibula had nonlinear or linear overlap with the lateral border of the tibia, regardless of the joint morphology. In this non-overlapping view, three Weber's indices for normal fibular length could be better visualized than the mortise view.

CONCLUSION

The syndesmotic cylinder in the proximal end of the incisura fibularis could be consistently placed parallel to the ground by internally rotating the tibia until there was a nonlinear or linear overlap between the proximal fibula and the tibia, regardless of the joint morphology.

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

AIMS

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.

METHODS

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.

RESULTS

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%.

CONCLUSION

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.

Strategies to Avoid Syndesmosis Malreduction in Ankle Fractures

Nearly half of surgically treated ankle fractures may have associated syndesmotic disruption, and the quality of reduction has been shown to affect functional outcomes. Malreduction ranges from 15% to 50% in the literature, and achieving anatomic reduction remains a significant challenge, even for experienced surgeons. Keys to success include having a stepwise plan and an understanding of reliable fluoroscopic parameters to help achieve reduction in both the coronal and sagittal planes. This article summarizes the literature on syndesmotic reduction and provides the authors' preferred technique using fluoroscopy.

[Research progress in diagnosis and treatment of distal tibiofibular syndesmosis injury]

Objective

To review the research progress in the diagnosis and treatment of distal tibiofibular syndesmosis injury.

Methods

The recent literature about distal tibiofibular syndesmosis injury was reviewed and analyzed.

Results

Distal tibiofibular syndesmosis injury is commonly seen in ankle joint injury, the anatomical complexities make diagnosis and treatment difficult. Preoperative physical examination, radiologic evaluation, and intraoperative stress-testing are important for the diagnosis. Aggressive treatment is also recommended for these injuries to prevent long-term chronic instability. Internal fixation is the main treatment, including metal screw, degradable screw, elastic fixation, and hybrid techniques. Metal screw fixation is still the current mainstream, but elastic fixation represented by Suture-button is more in line with the physiological characteristics of ankle joint, and the rate of secondary operation is low while the clinical outcome is satisfactory. The application prospect of elastic fixation is worthy of expectation.

Conclusion

It's crucial for patient with ankle fracture to repair the distal tibiofibular syndesmosis injury. How to diagnose the injury more accurately and simply, how to increase the success rate of reduction, and how to reduce the complications of surgery are still worthy for further exploration.

Getting the Starting Point Right: Prevention of Skiving and Fibular Cortical Breach During Suture Button Placement for Syndesmotic Ankle Injuries

The use of suture button (SB) devices in the treatment of syndesmotic ankle injuries is increasing. These constructs have demonstrated better syndesmotic reduction, improved clinical outcomes, and lower rates of hardware removal compared with screw fixation. However, placing a SB device without a fibular plate can be technically challenging. In this technique tip, we use an illustrative case to demonstrate a technique tip that minimizes the risk of anterior or posterior cortical breach of the fibula and helps facilitate more accurate placement of a SB device.Levels of Evidence: Level V: Expert opinion.

Syndesmosis Injury From Diagnosis to Repair: Physical Examination, Diagnosis, and Arthroscopic-assisted Reduction

Injuries to the tibio-fibular syndesmotic ligaments are different than ankle collateral ligament injuries and occur in isolation or combination with malleolar fractures. Syndesmotic ligament injury can lead to prolonged functional limitations and ultimately long-term ankle dysfunction if not identified and treated appropriately. The syndesmosis complex is a relatively simple construct of well-documented ligaments, but the dynamic kinematics and the effects of disruption have been a point of contention in diagnosis and treatment. Syndesmotic ligament injuries are sometimes referred to as "high ankle sprains" because the syndesmotic ligaments are more proximal than the collateral ligaments of the ankle joint. Rotational injuries to the ankle often result in malleolar fractures, which can be combined with ankle joint or syndesmotic ligament injuries. Most of the orthopaedic literature to this point has addressed syndesmosis ligament injuries in combination with fractures and not isolated syndesmotic ligament injuries. Thus, we propose a simplified general video guide to do the diagnostic examinations and arthroscopic-assisted reduction based on current evidence-based medicine.

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

PURPOSE

Disruption 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.

METHODS

Nine 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.

RESULTS

Both 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).

CONCLUSION

Ankle 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 EVIDENCE

Controlled laboratory study, Level V.

Dynamic Stabilization of Syndesmosis Injuries Reduces Complications and Reoperations as Compared With Screw Fixation: A Meta-analysis of Randomized Controlled Trials

BACKGROUND

Several devices for obtaining dynamic fixation of the syndesmosis have been introduced in recent years, but their efficacy has been tested in only a few randomized controlled trials (RCTs), without demonstrating any clear benefit over the traditional static fixation with screws.

PURPOSE

To perform a level 1 meta-analysis of RCTs to investigate the complications, subjective outcomes, and functional results after dynamic or static fixation of acute syndesmotic injuries.

STUDY DESIGN

Meta-analysis of RCTs.

METHODS

A systematic literature search was performed of the Medline/PubMed, Cochrane Central Register of Controlled Trials, and Embase electronic databases, as well as ClinicalTrials.gov for unpublished studies. Eligible studies were RCTs comparing dynamic fixation and static fixation of acute syndesmosis injuries. A meta-analysis was performed, while bias and quality of evidence were rated according to the Cochrane Database questionnaire and the Grading of Recommendations Assessment, Development and Evaluation guidelines.

RESULTS

Dynamic fixation had a significantly reduced relative risk (RR = 0.55, P = .003) of complications-in particular, the presence of inadequate reduction at the final follow-up (RR = 0.36, P = .0008) and the clinical diagnosis of recurrent diastasis or instability (RR = 0.10, P = .03). The effect was more evident when compared with permanent screws (RR = 0.10, P = .0001). The reoperation rate was similar between the groups (RR = 0.64, P = .07); however, the overall risk was reduced after dynamic fixation as compared with static fixation with permanent screws (RR = 0.24, P = .007). The American Orthopaedic Foot & Ankle Society score was significantly higher among patients treated with dynamic fixation-6.06 points higher (P = .005) at 3 months, 5.21 points (P = .03) at 12 months, and 8.60 points (P < .00001) at 24 months-while the Olerud-Molander score was similar. The visual analog scale for pain score was reduced at 6 months (-0.73 points, P = .003) and 12 months (-0.52 points, P = .005), and ankle range of motion increased by 4.36° (P = .03) with dynamic fixation. The overall quality of evidence ranged from "moderate" to "very low," owing to a substantial risk of bias, heterogeneity, indirectness of outcome reporting, and evaluation of a limited number of patients.

CONCLUSION

The dynamic fixation of syndesmotic injuries was able to reduce the number of complications and improve clinical outcomes as compared with static screw fixation-especially malreduction and clinical instability or diastasis-at a follow-up of 2 years. A lower risk of reoperation was found with dynamic fixation as compared with static fixation with permanent screws. However, the lack of patients or personnel blinding, treatment heterogeneity, small samples, and short follow-up limit the overall quality of this evidence.

Syndesmotic malreduction may decrease fixation stability: a biomechanical study

Background

This study aims to investigate the malreduction of syndesmosis and its effects on stability.

Methods

The biomechanical tests, including the three-dimensional (3D) displacement of the syndesmotic incisura, fibular rotation angle, and torque resistance, were performed on six cadaver legs. These specimens were first tested intact (intact group), then cut all the syndesmotic ligaments and fixed in anatomical position (anatomical model group) and test again. After that, syndesmosis was fixed in 1 cm malreduction (anterior and posterior displacement group) to do the same test.

Results

In internal or external load, there were significant differences in torque resistance and fibular rotation angle (internal t = 2.412, P = 0.036; external t = 2.412, P = 0.039) between the intact and post-malreduction groups. In internal rotation load, there were significant differences in sagittal displacement between the intact and post-malreduction groups (P = 0.011), and between the anatomical and post-malreduction groups (P = 0.020). In external rotation load, significant differences existed between the intact and ant-malreduction group (P = 0.034) in sagittal (anterior-posterior) displacement. Significant differences also existed between the intact and post-malreduction groups (P = 0.013), and between the anatomical and post-malreduction groups (P = 0.038) in coronal (medial-lateral) displacement.

Conclusions

Malreduction in different conditions does affect the stability of the syndesmotic fixation. The result of the study may reveal the biomechanical mechanism of poor clinical outcome in syndesmosis malreduction patients and pathological displacement patterns of the ankle under syndesmotic malreduction conditions.

Level of evidence

III

Better outcome for suture button compared with single syndesmotic screw for syndesmosis injury: five-year results of a randomized controlled trial

Aims

In a randomized controlled trial with two-year follow-up, patients treated with suture button (SB) for acute syndesmotic injury had better outcomes than patients treated with syndesmotic screw (SS). The aim of this study was to compare clinical and radiological outcomes for these treatment groups after five years.

Methods

A total of 97 patients with acute syndesmotic injury were randomized to SS or SB. The five-year follow-up rate was 81 patients (84%). The primary outcome was the American Orthopaedic Foot and Ankle Society (AOFAS) Ankle Hindfoot Scale. Secondary outcome measures included Olerud-Molander Ankle (OMA) score, visual analogue scale (VAS), EuroQol five-dimension questionnaire (EQ-5D), range of movement, complications, reoperations, and radiological results. CT scans of both ankles were obtained after surgery, and after one, two, and five years.

Results

The SB group had higher median AOFAS score (100 (interquartile range (IQR) 92 to 100) vs 90 (IQR 85 to 100); p = 0.006) and higher median OMA score (100 (IQR 95 to 100) vs 95 (IQR 75 to 100); p = 0.006). The SS group had a higher incidence of ankle osteoarthritis (OA) (24 (65%) vs 14 (35%), odds ratio (OR) 3.4 (95% confidence interval (CI) 1.3 to 8.8); p = 0.009). On axial CT we measured a significantly smaller mean difference in the anterior tibiofibular distance between injured and non-injured ankles in the SB group (–0.1 mm vs 1.2 mm; p = 0.016).

Conclusion

Five years after syndesmotic injury treated with either SB or SS, we found better AOFAS and OMA scores, and lower incidence of ankle OA, in the SB group. These long-term results favour the use of SB when treating an acute syndesmotic injury. Cite this article: Bone Joint J 2020;102-B(2):212–219.

Clinical Considerations to Reduce Saphenous Neurovascular Bundle Injury During Suture Button Fixation of Syndesmosis Injuries

OBJECTIVE

To document angles, from 2 difference starting points, or danger zones that should be avoided to minimize risk of injury or irritation to the saphenous neurovascular bundle (SNVB) during suture button (SB) fixation for distal tibiofibular syndesmosis injuries.

DESIGN

Retrospective imaging study.

SETTING

Academic Level 1 trauma center.

PATIENTS

Forty-eight randomly selected patients with healthy ankles and computed tomography scans for nonankle diagnoses.

MAIN OUTCOME MEASURES

Computed tomography scans and 3D reconstructed images were used to define the angle between the SNVB and 2 different fibular starting points, using the direct lateral (DL) and the posterolateral (PL) starting points. Descriptive analyses were performed to identify angles that should be avoided during suture button fixation. Distances from the SNVB using preset angles of 0, 10, 20, and 30 degrees were analyzed. In addition, the width of the SNVB, the midsubstance angle of the SNVB, and the distance from the 30-degree point to the tibialis anterior were recorded.

RESULTS

The mean angle between the SNVB and the standard DL starting point was 13.7 ± 5.0 degrees (P < 0.05), whereas the mean angle using the alternate PL starting point was 17.2 ± 5.3 degrees (P < 0.05). The SNVB width was 5.2 mm [range, 2.6-9.1 mm] (P < 0.05). The distances from the SNVB were greatest for the DL 30-degree group and the PL 0-degree group.

CONCLUSIONS

The results document angles that should be avoided when using suture button fixation for syndesmosis injuries. Device characteristics and surgery-related variables may require intraoperative modifications, and knowledge of this anatomical relationship may reduce SNVB injury during those situations. Considering our results, we recommend that surgeons place suture buttons from the DL starting point with a 30-degree trajectory to avoid injuries to the SNVB.

Diagnosis and treatment of tibiofibular syndesmosis lesions

The tibiofibular syndesmosis is a fibrous joint essential for ankle stability, whence the classical comparison with a mortise. Syndesmosis lesions are quite frequent in ankle trauma. This is a key element in ankle stability and lesions may cause pain or instability and, in the longer term, osteoarthritis. The lesions are often overlooked due to diagnostic difficulties, but collision sport with strong contact is the main culprit. Diagnosis, whether in the acute or the chronic phase, is founded on an association of clinical and paraclinical signs. Cross-sectional imaging such as MRI is fundamental to confirming clinical suspicion. Absence of tibiofibular diastasis no longer rules out the diagnosis. Stress CT and the introduction of weight-bearing CT are promising future diagnostic tools. Exhaustive osteo-ligamentous ankle assessment is necessary, as syndesmosis lesions may be just one component in more complex rotational instability. Therapeutically, arthroscopy and new fixation techniques, such as suture buttons, are opening up new perspectives, especially for chronic lesions (>6months). The present anatomic, epidemiological, diagnostic and therapeutic review does not preclude further clinical studies of rotational ankle instability with its strong risk of osteoarthritis.

Use of a Suture Button Device to Correct Syndesmotic Malreduction Caused by a Trans-Syndesmotic Screw

Ankle syndesmosis malreduction is a common problem that leads to significantly worse functional outcomes. This report describes the replacement of a rigid syndesmotic screw with a flexible suture button fixation device to correct fibular translation and tibiotalar malalignment related to screw contact with other tibial implants. Suture button devices, although more expensive, can result in less postoperative malreduction and lead to better functional outcomes. As seen in these cases, careful attention should be given to syndesmotic or tibiotalar reduction after screw placement around other tibial implants, and the screw can be exchanged to a suture button device to address malreduction, if needed. [Orthopedics. 2019; 42(5):e480-e484.].

Effect of a Dynamic Fixation Construct on Syndesmosis Reduction: A Cadaveric Study

OBJECTIVES

To explore what effect a dynamic fixation construct would have on the final reduction of the syndesmosis.

METHODS

Syndesmotic ligaments were sectioned in 10 cadaveric specimens. The syndesmosis was intentionally malreduced with a clamp, and the distance from the anterior edge of the fibula to the anterior incisura of the tibia was measured to quantify the sagittal syndesmotic displacement (SSD). A 3.5-mm quadricortical screw was then placed, the clamp was removed, and the SSD measured. The clamp was then replaced, and a suture-button construct (Knotless Tightrope; Arthrex Inc, Naples, FL) was then placed through the bone tunnel, the clamp was again removed, and the SSD was measured.

RESULTS

In all cases, the fibula reduced to within 1 mm of its native anatomical position with the dynamic construct. The static screw construct, however, maintained an identical SSD measurement as the clamped malreduction. The dynamic suture-button construct reliably improved the SSD (P < 0.0001).

CONCLUSIONS

Our study demonstrates that dynamic fixation constructs can help restore anatomical alignment in the case of syndesmotic malreduction. The size difference between the suture diameter and drill hole effectively allows the fibula to be pulled and seated into the tibial incisura fibularis. These findings should not be viewed as a justification to ignore the syndesmotic reduction; however, they do validate an important benefit of dynamic fixation that has been found in the recent clinical literature.

LEVEL OF EVIDENCE

Therapeutic Level III.

Diagnosis and treatment of ankle syndesmosis injuries with associated interosseous membrane injury: a current concept review

BACKGROUND

Tibiofibular syndesmosis injury leads to ankle pain and dysfunction when ankle injuries are not treated properly. Despite several studies having been performed, many questions about diagnosis and treatment remain unanswered, especially in ankle syndesmosis injury with interosseous membrane injury. Therefore, the purpose of this study was to help guide best practice recommendations.

METHODS

This review explores the mechanism of injury, clinical features, diagnosis methods, and the treatment strategy for ankle syndesmosis injury with interosseous membrane injury to highlight the current evidence in terms of the controversies surrounding the management of these injuries.

RESULTS

Radiological and CT examination are an important basis for diagnosing ankle syndesmosis injury. Physical examination combined with MRI to determine the damage to the interosseous membrane is significant in guiding the treatment of ankle syndesmosis injury with interosseous membrane injury. In the past, inserting syndesmosis screws was the gold standard for treating ankle syndesmosis injury. However, there were increasingly more controversies regarding loss of reduction and broken nails, so elastic fixation has become more popular in recent years.

CONCLUSIONS

Anatomical reduction and effective fixation are the main aspects to be considered in the treatment of ankle syndesmosis injury with interosseous membrane injury and are the key to reducing postsurgery complications.

Anatomic Ligament Repairs of Syndesmotic Injuries

Poor clinical results are seen with syndesmotic injuries in the setting of ankle sprains and ankle fractures. The goal of syndesmosis repair is to restore the normal anatomic relationship of the distal tibiofibular joint and prevent ankle arthritis. Indications for surgical intervention for isolated syndesmotic injuries include frank syndesmosis diastasis, medial clear space widening on plain radiographs, significant radiographic syndesmosis diastasis during stress examination, or subtle syndesmotic diastasis detected by arthroscopic evaluation. Complications after syndesmosis repair include symptomatic hardware, malreduction, and arthritis. Anatomic reduction of the syndesmosis leads to better outcomes following surgery.

Tibiofibular relationships of the normal syndesmosis differ by age on axial computed tomography-Anterior fibular translation with age

INTRODUCTION

This study aimed to assess the tibiofibular relationships of normal syndesmosis on axial computed tomography (CT) images and evaluate the measurement differences by gender, age, and body sides.

PATIENTS AND METHODS

The cases of 120 volunteers who underwent bilateral ankle CT were retrospectively reviewed. Volunteers were divided into three groups of 40 (20 men and 20 women) as follows: 20-40, 40-60, and 60-80 years old. Radiographic evaluation included the anterior tibiofibular clear space (ATFCS), posterior tibiofibular clear space (PTFCS), anterior tibiofibular interval (ATFI), length of incisura (LI), depth of incisura (DI), and fibular width (FW). Each measured parameter was compared based on gender, age, and body sides. To calibrate anatomical variations among the volunteers, ATFCS, PTFCA, and ATFI were expressed as ratios of FW.

RESULTS

PTFCS and ATFI were significantly larger in the men (p = 0.001, 0.001). LI and FW were significantly smaller in the women (p <0.001, <0.001). Calibrated ATFCS, PTFCS, and ATFI did not differ between the genders. ATFCS, PTFCS, and ATFI were significantly different among the age groups (p = 0.001, 0.001, and <0.001, respectively). These calibrated parameters showed significant differences according to age (p = 0.009, 0.006, and <0.001, respectively). There were no significant differences between sides. All CT measurements, except DI, showed high intra- and inter-observer reliabilities.

CONCLUSIONS

Axial CT images of the normal syndesmosis showed significant differences according to gender and age, but not between sides. In light of the anatomical variation, narrowing of the syndesmotic joint due to anterior translation of the fibula following aging may represent the most significant finding.

LEVEL OF EVIDENCE

Level IV, case series.

Achilles Tension Mitigates Fibular Malalignment Measured in Cadaveric Studies of Syndesmotic Clamping

BACKGROUND:

Fibular malreduction is becoming a commonly recognized complication of surgical repair of the syndesmosis when a reduction clamp is used. The goal of this work was to determine the interdependent effects of transsyndesmotic reduction clamp position and applied compression force on fibular alignment in a realistic cadaveric preparation of complete syndesmotic injury.

METHODS:

Six through-the-knee cadaveric specimens were CT scanned intact, with the distal syndesmosis fully destabilized, and with 53, 102, and 160 N clamping forces each applied along an anteriorly, centrally, and posteriorly directed transsyndesmotic axis. Testing was repeated incorporating 178 N of Achilles tendon tension using all 3 clamping forces applied along the centrally directed axis. Fibular reduction was automatically quantified from CT scan-generated bony surfaces as rotation of the fibula around the tibia, rotation of the fibula within the incisura, medial/lateral fibular displacement, and anterior/posterior fibular displacement.

RESULTS:

Transsyndesmotic clamping along the anteriorly directed axis resulted in the best reduction quality by all 4 quantified measures. Along the centrally and posteriorly directed axes, progressively greater forces caused significantly greater sagittal plane fibular malreduction. Addition of Achilles tension reduced the magnitude of fibular malreduction and overcompression.

CONCLUSION:

Placing the medial tine of a transsyndesmotic reduction clamp on the anterior medial tibia resulted in the most accurate syndesmotic reduction and provided some protection against overcompression with large reduction clamp forces. Achilles tension appeared to contribute to reduction, decreasing the magnitude of measured malreduction from clamping.

CLINICAL RELEVANCE:

Previous studies estimating fibular malpositioning in cadaveric models that lacked passive muscle tension may have overestimated expected magnitudes of malalignment in patients treated with syndesmotic clamping. However, syndesmotic malreduction, particularly in the sagittal plane, was a real complication of syndesmotic clamping that was reduced by using an anterior position of the medial tine on the tibia.

Syndesmosis Fixation in Unstable Ankle Fractures Using a Partially Threaded 5.0-mm Cannulated Screw

The present study evaluated the radiographic outcomes of syndesmosis injuries treated with a partially threaded 5.0-mm cannulated screw. The present study included 58 consecutive patients with syndesmosis injuries concurrent with ankle fractures who had undergone operative fixation with a partially threaded 5.0-mm cannulated screw to repair the syndesmosis injury. Radiographic indexes, including the medial clear space, tibiofibular overlap, tibiofibular clear space, and fibular position on the lateral radiograph, were measured on the preoperative, immediate postoperative, and final follow-up radiographs. The measurements were compared between the injured and intact ankles. All preoperative radiographic indexes, including the medial clear space (p < .001), tibiofibular overlap (p < .001), tibiofibular clear space (p < .001), and fibular position on the lateral radiograph (p = .026), were significantly different between the injured and intact ankles. The medial clear space of the injured ankle was significantly wider than that of the intact ankle preoperatively (p < .001) and had become significantly narrower immediately postoperatively (p < .001). Finally, the medial clear space was not significantly different between the injured and intact ankles at the final follow-up examination (p = .522). No screw breakage or repeat fractures were observed. A 5.0-mm partially threaded cannulated screw effectively restored and maintained the normal relationship between the tibia and fibula within the ankle mortise with a low risk of complications. This appears to be an effective alternative technique to treat syndesmosis injuries concurrent with ankle fractures.

Biomechanical Comparison of 3 Syndesmosis Repair Techniques With Suture Button Implants

Background:

Suture button fixation of syndesmotic injury is growing in popularity, as it has been shown to provide adequate stability in a more cost-effective manner than screw fixation while allowing more physiologic distal tibiofibular joint motion. However, the optimal repair technique and implant orientation have yet to be determined.

Purpose/Hypothesis:

The purpose of this study was to biomechanically compare 3 suture button construct configurations/orientations for syndesmosis fixation: single, parallel, and divergent. The authors hypothesized that all 3 methods would provide adequate stabilization but that the divergent technique would be the most stable.

Study Design:

Controlled laboratory study.

Methods:

The fixation strengths of 3 stabilization techniques with suture button devices were compared with 10 cadaveric legs each (N = 30). Ankle motion under cyclic loading was measured in multiple planes: first in the intact state, then following simulated syndesmosis injury, and then following fixation with 1 of 3 randomly assigned constructs—1 suture button, 2 suture buttons in parallel, and 2 divergent suture buttons. Finally, axial loading with external rotation was applied to failure.

Results:

All syndesmotic fixation methods provided stability to the torn state. There was no statistically significant difference among the 3 fixation techniques in biomechanical stability. Failure most commonly occurred through fibular fracture at supraphysiologic loads.

Conclusion:

Suture button implant fixation for syndesmotic injury appears to provide stability to the torn syndesmosis, and the configuration of the fixation does not appear to affect the strength or security of the stabilization.

Clinical Relevance:

This study provides further insight into the biomechanics and optimal configuration of suture button fixation of the torn syndesmosis. Based on these results, the addition of a second suture button may not significantly contribute to immediate postoperative stability.

Suture-Button Fixation and Mini-Open Anterior Inferior Tibiofibular Ligament Augmentation Using Suture Tape for Tibiofibular Syndesmosis Injuries

Tibiofibular fixation using suture-button implants is an optional method for the surgical treatment of syndesmosis injuries. Although good clinical outcomes have been reported, inadequate stability between the tibia and fibula has also been documented. Thus, suture-button fixation is not considered the reference standard. For surgical treatment of lateral ligament injuries of the ankle, good treatment outcomes have also been reported with ligament augmentation using nonabsorbable suture tape. Ligament augmentation tape with suture-button fixation could also be promising for improved treatment outcomes in syndesmosis injuries. We describe suture-button fixation together with mini-open anterior inferior tibiofibular ligament augmentation using suture tape for treatment of syndesmosis injuries.

Medial Structure Injury During Suture Button Insertion Using the Center-Center Technique for Syndesmotic Stabilization

BACKGROUND

The center-center technique for syndesmosis fixation has been described as an improved and reliable technique for proper reduction of the syndesmosis during ankle fracture repair. Concurrently, the use of flexible fixation with a suture button is becoming an established means of syndesmosis stabilization. The purpose of this cadaveric study was to assess for medial structure injury during the placement of a suture button using the center-center technique for ankle syndesmosis repair at 3 insertion intervals.

METHODS

Simulated open syndesmosis repair was performed on 10 cadaveric specimens. Three intervals were measured at 10 mm, 20 mm, and 30 mm proximal to the level of the distal tibial articular surface along the fibula. Proper longitudinal alignment of the center-center technique was completed under fluoroscopic guidance and was marked on the medial aspect of the tibia. The 3 intervals were drilled in the appropriate technique trajectory. The suture button was subsequently passed through each drill-hole interval. A single observer used a digital caliper to measure the distance from each suture button aperture with respect to the tibialis anterior tendon, tibialis posterior tendon, and greater saphenous vein and nerve.

RESULTS

A total of 30 interval measurements (10 cadavers with 3 suture button segments each) were used for data analysis. Direct impingement on the greater saphenous vein was seen in 11 of 30 (36.6%) interval measurements. Six of the 11 (54.5%) observed saphenous structure impingement events occurred at the 10-mm drill hole.

CONCLUSION

The results of the present study suggest that the use of the center-center technique for syndesmosis repair with suture button fixation risks preventable injury to the greater saphenous neurovasculature.

CLINICAL RELEVANCE

To understand the medial ankle anatomy, as it pertains to insertion of flexible syndesmotic fixation in a cadaveric model, to aid in prevention of clinical iatrogenic injury.

Radiographic Change of the Distal Tibiofibular Joint Following Removal of Transfixing Screw Fixation

BACKGROUND

Syndesmosis disruptions in the ankle joint are typically treated with anatomic reduction followed by transfixing screw and/or suture button fixation. The purpose of our study was to analyze the effects of the removal of transfixing screws on syndesmosis integrity using plain radiographs and computed tomography (CT) scans.

METHODS

Twenty-nine cases (29 patients) who had been treated with transfixing screw fixation for syndesmosis disruptions were studied prospectively. Plain radiographs and CT scans were obtained 1 day before and 3 months after the removal of transfixing screws. The tibiofibular clear space (TCS) and tibiofibular overlap (TFO) were measured on plain radiographs, and the anterior and posterior measurement ratio (A/P ratio) of the syndesmosis was measured on axial CT scans to radiographically analyze the effect of the removal of screws on syndesmosis integrity.

RESULTS

On plain radiographs, syndesmosis diastasis was not observed before or after the removal of transfixing screws. No statistically significant difference was found in the TCS and the TFO between measurements at prescrew removal and at postscrew removal ( P = .761 and .628, respectively). However, the syndesmosis was found malreduced on CT scans in 7 cases (24.1%) before screw removal. All 7 cases showed anterior malreduction of the syndesmosis, 5 (71.4%) of which spontaneously reduced after screw removal. The A/P ratio of the 7 cases decreased from a mean of 1.37 (range, 1.26-1.61) at prescrew removal to a mean of 1.12 (range, 0.96-1.25) at postscrew removal ( P = .016).

CONCLUSION

Syndesmosis malreduction not observed on plain radiographs after performing transfixing screw fixation was identified with CT scans. Of the cases with a malreduced syndesmosis, 71.4% showed spontaneous reduction after screw removal. Therefore, we believe the removal of transfixing screws is recommended after confirming malreduction on CT scans, although plain radiographs demonstrate anatomic reduction.

LEVEL OF EVIDENCE

Level II, prospective prognostic study.

Effect of Posterior Malleolus Fracture on Syndesmotic Reduction: A Cadaveric Study

BACKGROUND

Syndesmotic malreduction and fractures of the posterior malleolus negatively influence outcomes of rotational ankle fractures. Recent data have shown that posterior malleolus fixation contributes to the stability of the syndesmosis. The purpose of this study was to analyze syndesmotic reduction within the context of different sizes of posterior malleolus fracture fragments and different qualities of reduction.

METHODS

A model of stage-IV supination-external rotation injury was created in 9 through-the-knee cadaveric specimens. The specimens were randomized to receive either a small (one-third of the incisura, n = 4) or a large (two-thirds of the incisura, n = 5) posterior malleolus fracture. High-resolution computed tomography (CT) scans were obtained of each intact specimen and then with clamp reduction of the syndesmosis along with a fracture fragment that was (1) unreduced, (2) anatomically reduced, or (3) fixed with a 4.8-mm-gap malreduction. Syndesmotic reduction in both the anterior-posterior and the medial-lateral direction was assessed relative to the intact specimen.

RESULTS

Clamp reduction of the syndesmosis increased medial translation of the distal part of the fibula in the specimens with an unfixed or an anatomically fixed posterior malleolus fracture fragment and caused lateral displacement of the distal part of the fibula in the specimens with gap malreduction of the posterior malleolus fracture. Clamp reduction of the syndesmosis caused a slight anterior shift of the fibula in the specimens with a small unfixed or anatomically fixed posterior malleolus fracture fragment and caused a posterior shift of the fibula in the specimens with gap malreduction of a large fragment.

CONCLUSIONS

The overall anterior-posterior reduction of the syndesmosis was generally unaffected by a posterior malleolus fracture except when there was malreduction of a large fragment. Medial-lateral syndesmotic reduction was affected by the conditions of the posterior malleolus fixation, with malreduction of the posterior malleolus leading to syndesmotic malreduction.

CLINICAL RELEVANCE

When posterior malleolus fractures occur with syndesmotic injury, anatomic fracture reduction and fixation are paramount as they can affect syndesmotic reduction, especially with larger fragments.

Randomized Trial Comparing Suture Button with Single Syndesmotic Screw for Syndesmosis Injury

BACKGROUND

This study compared clinical and radiographic results between patients who underwent stabilization of an acutely injured syndesmosis with a suture button (SB) and those treated with 1 quadricortical syndesmotic screw (SS).

METHODS

Ninety-seven patients, 18 to 70 years old, with an ankle injury that included the syndesmosis were randomized to 2 groups: SB (48 patients) and SS (49). The main outcome measure was the score on the American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot scale. The secondary outcome measures were the Olerud-Molander Ankle (OMA) score, visual analog scale (VAS), and EuroQol-5D (EQ-5D) Index and VAS. Computed tomography (CT) scans of both ankles were obtained at 2 weeks and 1 and 2 years after surgery. Both groups were allowed partial weight-bearing at 2 weeks and full weight-bearing at 6 weeks. The mean time for SS removal was 85.9 days (range, 39 to 132 days) after surgery. The patients were followed at 6 weeks, 6 months, and 1 and 2 years. Two years of follow-up were completed for 87 (90%) of the patients (46 in the SB group and 41 in the SS group).

RESULTS

The SS group had more injuries to the posterior malleolus than the SB group. At 2 years, the median AOFAS score was higher in the SB group than in the SS group (96 [interquartile range, or IQR, 90 to 100] versus 86 [IQR, 80 to 96]; p = 0.001), as was the median OMA score (100 [IQR, 95 to 100] versus 90 [IQR, 75 to 100]; p < 0.001). The SB group reported less pain during walking at 2 years than the SS group (median VAS score, 0 [IQR, 0 to 1] versus 1 [IQR, 0 to 2]; p = 0.008) and less pain during rest (median VAS score, 0 [IQR, 0 to 0] versus 0 [IQR, 0 to 1]; p = 0.04). There was no difference between treatments groups with regard to pain at night or during daily activities at 2 years. The SB group had a higher median EQ-5D Index score at 2 years (1.0 [IQR, 1 to 1] versus 0.88 [IQR, 0.8 to 1.0]; p = 0.005). Twenty of 40 patients in the SS group had a difference in the tibiofibular distance of ≥2 mm between the injured and uninjured ankles at 2 years, compared with 8 of 40 in the SB group (p = 0.009). Seven patients in the SS group had symptomatic recurrent syndesmotic diastasis during the treatment period compared with none in the SB group (p = 0.005).

CONCLUSIONS

The patients treated with an SB had higher AOFAS scores, OMA scores, and EQ-5D Index scores as well as lower (better) VAS scores for pain during walking and pain during rest. Also, the SB group had less widening seen radiographically at 2 years than did the patients in the SS group. No differences in the scores for pain at night or during daily activities were identified.

LEVEL OF EVIDENCE

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

Epidemiology and return to play following isolated syndesmotic injuries of the ankle: a prospective cohort study of 3677 male professional footballers in the UEFA Elite Club Injury Study

Aim

To determine the epidemiology of isolated syndesmotic injuries in professional football players.

Methods

Data from 15 consecutive seasons of European professional football between 2001 and 2016 contributed to the dataset of this study. Match play and training data from a total of 3677 players from 61 teams across 17 countries have been included. Team medical staff recorded player exposure and time loss injuries. Injury incidence was defined as the number of injuries per 1000 player-hours. Injury burden was defined as number of days absence per 1000 player-hours. Seasonal trends for isolated syndesmotic injury incidence, isolated syndesmotic injury proportion of ankle ligament injuries and isolated syndesmotic injury burden were analysed via linear regression.

Results

The isolated syndesmotic injury incidence was 0.05 injuries per 1000 hours of exposure (95% CI 0.04 to 0.06) or one injury per team every three seasons. The injury incidence during match play was 13 times higher compared with during training, 0.21 (95% CI 0.16 to 0.26) and 0.02 (95% CI 0.01 to 0.02), respectively. Out of the 1320 ankle ligament injuries registered during the 15 seasons, 94 (7%) were diagnosed as isolated syndesmotic injuries. An annual increase in injury incidence was observed (R2=0.495, b=0.003, 95% CI 0.001 to 0.004, P=0.003). However, no significant annual change of injury burden was observed (R2=0.033, b=0.032, 95% CI −0.073 to 0.138, P=0.520). Seventy-four per cent of the injuries were contact related, and the mean (±SD) absence following an isolated syndesmotic injury was 39 (±28) days.

Conclusions

The incidence of isolated syndesmotic injuries in elite professional European football annually increased between 2001 and 2016.

Open versus minimally invasive fixation of a simulated syndesmotic injury in a cadaver model

Background

Malreduction of unstable syndesmotic ankle fractures is common. This study compared the reduction quality of an anterolateral open technique (OT) versus a conventional minimally invasive technique (MIT).

Methods

Fourteen fresh-frozen lower torso specimens with 28 matched lower extremities underwent computed tomography (CT) to measure syndesmosis position before dissection. Reduction was performed using direct visualization and fluoroscopy for the OT group (right-sided specimens) and fluoroscopy only for the MIT group (left-sided specimens). Fixation was achieved with 2 cortical screws. Measurements were repeated with postfixation CT scans. Statistical analysis used a two-tailed t test (α = 0.05).

Results

Mean posterior fibula-tibia distance decreased after OT by 0.3 ± 0.5 mm and increased after MIT by 0.7 ± 0.6 mm (P = 0.025 for difference between techniques). Mean anterior fibula-tibia distance decreased after OT by 0.4 ± 0.2 mm (P = 0.007) and did not change significantly after MIT (− 0.01 ± 0.4 mm (P = 0.686). Mean anterior translation after OT was 0.04 ± 0.4 mm (P = 0.856), and mean posterior translation after MIT was 0.3 ± 0.7 mm (P = 0.434). Mean medialization after OT was 0.3 ± 0.4 mm (P = 0.132), and mean lateralization after MIT was 0.2 ± 0.6 mm (P = 0.446).

Conclusions

Both techniques produced near-anatomic reduction of the fibula, with MIT producing significantly more internal rotation malreduction than OT. OT appears to restore near-anatomic fibula position, although this did not differ significantly from the results of MIT. We conditionally recommend OT when closed reduction of the syndesmosis cannot be obtained.

Medial Clamp Tine Positioning Affects Ankle Syndesmosis Malreduction

OBJECTIVES

To determine whether the position of the medial clamp tine during syndesmotic reduction affected reduction accuracy.

DESIGN

Prospective cohort.

SETTING

Urban Level 1 trauma center.

PATIENTS

Seventy-two patients with operatively treated syndesmotic injuries.

INTERVENTION

Patients underwent operative fixation of their ankle syndesmotic injuries using reduction forceps. The position of the medial clamp tine was then recorded with intraoperative fluoroscopy. Malreduction rates were then assessed with bilateral ankle computerized tomography.

MAIN OUTCOME MEASUREMENT

Fibular position within the incisura was measured with respect to the uninjured side to determine whether a malreduction had occurred. Malreductions were then analyzed for associations with injury pattern, patient demographics, and the location of the medial clamp tine.

RESULTS

A statistically significant association was found between medial clamp position and sagittal plane syndesmosis malreduction. In reference to anterior fibular translation, there was a 0% malreduction rate in the 18 patients where the clamp tine was placed in the anterior third, a 19.4% malreduction rate in the middle third, and 60% malreduction rate in the posterior third (P = 0.006). In reference to posterior fibular translation, there was a 11.1% malreduction when clamp placement was in the anterior third, a 16.1% malreduction rate in the middle third, and 60% malreduction rate in the posterior third (P = 0.062). There were no significant associations between medial clamp position and coronal plane malreductions (overcompression or undercompression) (P = 1).

CONCLUSIONS

When using reduction forceps for syndesmotic reduction, the position of the medial clamp tine can be highly variable. The angle created with off-axis syndesmotic clamping is likely a major culprit in iatrogenic malreduction. Sagittal plane malreduction appears to be highly sensitive to clamp obliquity, which is directly related to the medial clamp tine placement. Based on these data, we recommend placing the medial clamp tine in the anterior third of the tibial line on the lateral view to minimize malreduction risk.

LEVEL OF EVIDENCE

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