Increased Reduction Clamp Force Associated With Syndesmotic Overcompression

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

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

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.

Does Proximal Placement of the Syndesmotic Reduction Clamp Affect the Optimal Position for the Medial Tine? A Cadaveric Pilot Study

Sagittal plane syndesmotic malreduction is associated with off-axis, eccentric reduction clamping and preferential placement of the medial tine anteriorly has been proposed to minimize the malreduction risk. Although clamp placement 1cm proximal to the plafond is recommend, no previous study has assessed whether differences in the anatomic position of the fibula within the incisura (eccentric 1cm superior and concentric 2 cm superior to the tibial plafond) affect the optimal position for the clamps medial tine during reduction of the syndesmosis. The purpose of the present cadaveric pilot study was to evaluate and compare the sagittal syndesmotic malreduction rate with various clamping vectors, 1cm and 2cm from the tibial plafond, respectively. Six through the knee cadaveric specimens were obtained. Kirschner wires and a surgical maker were used to denote placement of the reduction clamp laterally on the peroneal ridge of the fibula, and medially within the anterior, middle, and posterior thirds (Zones A, B, C) of tibia's width; 1 cm and 2 cm from the plafond. CT scans were obtained as controls, followed by destabilization of the syndesmosis. Reductions were then performed sequentially at each level (1 cm, 2 cm) and zone (A, B, C); and CT scans repeated for assessment. In most specimens (n = 5), an eccentric (1 cm) to concentric (2 cm) positional transition was observed within incisura fibularis. The transition altered the resulting fibular displacements in some specimens (2A anterior, vs 2B posterior), resulting in a higher malreduction rate with anterior (zone 2A, 33%) vs central (Zone 2B, 17%) positioning of medial tine. Although no definitive conclusions can be reached from the present pilot study, future studies with a greater number of specimens and clamping vectors are warranted to determine whether positional transitions of the fibula within the incisura fibularis affect the optimal position for the clamps medial tine.

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.

Comparison of Different Magnitudes of Applied Syndesmotic Clamp Force: A Cadaveric Study

Overcompression of the ankle syndesmosis was once thought to be improbable. Recent studies using computerized tomography (CT) however, have demonstarted otherwise; raising pertinent questions regarding the factors associated with and consequences of syndesmotic overcompression. The purpose of the present study was to directly compare different magnitudes of applied clamp force on the coronal reduction of ankle syndesmosis. Eight through-the-knee cadaveric specimens were obtained. Fiducial cannulated screws were placed in the tibia and fibula to standardize placement of the reduction clamp's tines. CT scans were obtained as baseline controls, followed by destabilization of the syndesmosis. Reductions were then performed using a clamp equipped with an inline load cell, and objective forces (60, 80, 100, 120, 140, and 160 N) applied sequentially to each of the specimens. The syndesmosis was fixed with a single quadricortical screw, and CT were scans repeated. Applied clamp forces of 60 and 80 N resulted in lateral fibular displacement and undercompression (42.9% and 57.1%, respectively), whereas forces of 140 and 160 N resulted in medial fibular displacement (p = .011 and p = .001) and overcompression (100%). The smallest mediolateral displacements were observed with 100 and 120 N, respectively. Malreduction assessment with CT was superior to traditional radiographs [r(54) = 0.22; 95% confidence interval -0.04 to 0.45; p = .101]. In our cadaveric model, an applied clamp force of 100 N most effectively mitigated iatrogenic coronal syndesmotic malreduction from under- or overcompression. Although additional research is warranted, based on the data, inherent variabilities in the applied clamp force by surgeons appear to contribute to the unacceptably high coronal syndesmotic malreduction rate.

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.

Is the Fibular Station on Lateral Ankle Radiographs Symmetric? A Retrospective Observational Radiographic Study

BACKGROUND

Precise reduction of a syndesmosis after disruption is critical to improve patient physical function. Intraoperative lateral radiographs of the unaffected ankle are often used in clinical practice as a template for anatomic syndesmotic reduction because sagittal plane malreduction is common. However, there is little data to suggest fibular station, or the position of the fibula in the AP plane on the lateral radiograph, is symmetric side-to-side in patients.

QUESTIONS/PURPOSES

(1) Is the position of the fibula in the AP plane (fibular station) on lateral ankle radiographs symmetric in an individual? (2) Do the measurements used to judge the position of the fibula on lateral radiographs have good inter- and intraobserver reliability?

METHODS

Over the period from August 2016 to October 2018, we identified 478 patients who presented to an orthopaedic clinic with forefoot and midfoot complaints. Skeletally mature patients with acceptable bilateral lateral ankle radiographs, which are common radiographs obtained for new patients to clinic for any complaint, were included. Based on that, 52% (247 of 478 patients) were included with most (22%, 107 patients) excluded for poor lateral radiographs. The most common diagnosis in the patient cohort was midfoot OA (14%, 35 patients). The median (range) age of the included patients was 54 years (15 to 88), and 65% (159 of 247) of the patients were female. Fibular station, defined as the position of the fibula in the AP plane, and fibular length were measured using a digital ruler and goniometer on lateral radiographs. A paired t-test was used to determine if no difference in fibular station existed between the left and right ankles. With 247 paired-samples, with 80% power and an alpha level of 0.05, we could detect a difference between sides of 0.008 for the posterior ratio, 0.010 for the anterior ratio, and 0.012 for fibular length. Two readers, one fellowship-trained orthopaedic traumatologist and one PGY-4, measured 40 patients to determine the inter- and intraobserver reliability by intraclass correlation coefficient (ICC).

RESULTS

The posterior fibular station (mean right 0.147 [σ = 0.056], left 0.145 [σ = 0.054], difference = 0.03 [95% CI 0 to 0.06]; p = 0.59), anterior fibular station (right 0.294 [σ = 0.062], left 0.299 [σ = 0.061], difference = 0.04 [95% CI 0 to 0.08]; p = 0.20), and fibular length (right 0.521 [σ = 0.080], left 0.522 [σ = 0.078], difference = 0.05 [95% CI 0.01 to 0.09]; p = 0.87) ratios did not differ with the numbers available between ankles. Inter- and intraobserver reliability were excellent for the posterior ratio (ICC = 0.928 and ICC = 0.985, respectively) and the anterior ratio (ICC = 0.922 and ICC = 0.929, respectively) and moderate-to-good for the fibular length ratio (ICC = 0.732 and ICC = 0.887, respectively).

CONCLUSION

The use of lateral radiographs of the contralateral uninjured ankle appears to be a valid template for determining the position of the fibula in the sagittal plane. However, further prospective studies are required to determine the efficacy of this method in reducing the syndesmosis over other methods that exists.

LEVEL OF EVIDENCE

Level III, diagnostic study.

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.

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.

Operative Setup to Improve Sagittal Syndesmotic Reduction: Technical Tip

We analyzed the operative measures that may be used to reduce the likelihood of sagittal syndesmotic malreduction. Hence, we propose a simple technical tip to avoid sagittal plane malreduction of the fibula within the syndesmosis in ankle fractures. Supporting the leg under the heel should be avoided when performing syndesmotic reduction for unstable malleolar fractures, and support under the calf should be used instead. Our observations have been confirmed in 6 cadaver specimens. We observed that there was a significant anterior subluxation of the fibula when the leg was supported under the heel. No significant difference between the intact and unstable state was present when the leg was supported under the calf. In conclusion, during syndesmotic reduction and fixation in supine position, supporting the foot under the heel should be avoided.

Comparison of Clamp Reduction and Manual Reduction of Syndesmosis in Rotational Ankle Fractures: A Prospective Randomized Trial

An optimal outcome of surgical treatment for a syndesmotic injury depends on accurate reduction and adequate fixation. It has been suggested that the use of a reduction clamp for reduction of the syndesmosis results in better reduction and a lower rate of redisplacement than manual reduction. However, these concepts have never been scientifically evaluated. We compared these 2 methods in a prospective randomized trial. A total of 85 acute ankle rotational fractures combined with syndesmotic injury were randomized to syndesmosis reduction with either a reduction clamp or manual manipulation. Reduction of the syndesmosis was assessed radiographically by measuring the tibiofibular clear space, tibiofibular overlap, and the medial clear space immediately postoperatively and at the final follow-up examination. Ankle joint range of motion, visual analog scale score, Olerud-Molander ankle scoring system, and complications were obtained at the last follow-up visit to assess the clinical outcomes. Of the 3 radiographic measurements, the tibiofibular clear space and tibiofibular overlap differed significantly between the 2 groups (p < .05). The clinical outcomes did not differ significantly between the 2 groups (p > .05). Although differences were found in the radiographic measurements, most syndesmoses in both groups were within the normal range at the final follow-up visit, and the 2 methods of syndesmosis reduction provided similar clinical outcomes. Accordingly, the results of the present study suggest that both of these methods are effective and reliable for reduction of the syndesmosis in rotational ankle fractures.

[Recent progress in foot and ankle surgery]

The article focuses on the recent progress in foot and ankle surgery, including the diagnosis of disease, treatment protocols, outcomes, and evaluation tools as well as other innovations. New and accurate diagnostic modalities and measurements have undergone a breakthrough. Diagnostic modalities tend to be simpler and less expensive. Measurement tools also change to simpler and more accurate. The accuracy and efficacy of surgery and the minimally invasive method have become more popular and important. New treatments and basic research have also made breakthroughs.

A Novel Indirect Reduction Technique in Ankle Syndesmotic Injuries: A Cadaveric Study

OBJECTIVE

To describe a novel technique using preoperative computed tomography (CT) to plan clamp tine placement along the trans-syndesmotic axis (TSA). We hypothesized that preoperative CT imaging provides a reliable template on which to plan optimal clamp tine positioning along the TSA, reducing malreduction rates compared with other described techniques.

METHODS

CT images of 48 cadaveric through-knee specimens were obtained, and the TSA was measured as well as the optimal position of the medial clamp tine. The syndesmosis was then fully destabilized. Indirect clamp reductions were performed with the medial clamp tine placed at positions 10 degrees anterior to the TSA, along the TSA, and at both 10 and 20 degrees posterior to the TSA. The specimens were then separately reduced using manual digital pressure and palpation alone. CT was performed after each clamp and manual reduction.

RESULTS

On average, reduction clamp tines were within 3 ± 2 degrees of the desired angle and within 5% ± 4% of the templated location along the tibial line for all clamp reduction attempts. Palpation and direct visualization produced the overall lowest malreduction rates in all measurements: 4.9% and 3.0%, respectively. Off-axis clamping 10 degrees anterior or 20 degrees posterior to the patient-specific TSA demonstrated an increased overall malreduction rate: 15.8% and 11.3%, respectively. Significantly more over-compression occurred when a reduction clamp was used versus manual digital reduction alone (8.6% vs. 0%).

CONCLUSIONS

Reduction clamp placement directly along an optimal clamping vector can be facilitated by preoperative CT measurements of the uninjured ankle. However, even in this setting, the use of reduction clamps increases the risk for syndesmotic malreduction and over-compression compared with manual digital reduction or direct visualization.

Effect of Ankle Position on Tibiotalar Motion With Screw Fixation of the Distal Tibiofibular Syndesmosis in a Fracture Model

BACKGROUND

Anatomic reduction and fixation of the syndesmosis in traumatic injuries is paramount in restoring function of the tibiotalar joint. While overcompression is a potential error, recent work has called into question whether ankle position during fixation really matters in this regard. Our study aimed to corroborate more recent findings using a fracture model that, to our knowledge, has not been previously tested.

METHODS

Twenty cadaver leg specimens were obtained and prepared. Each was tested for tibiotalar motion under various conditions: intact syndesmosis, intact syndesmosis with lag screw compression, pronation external rotation type 4 (PER-4) ankle fracture with syndesmotic disruption, and single-screw syndesmotic fixation followed by plate and screw fracture and syndesmotic screw fixation. In each situation, the ankle was held in alternating plantarflexion and dorsiflexion when inserting the syndesmotic screw with the subsequent amount of maximal dorsiflexion being recorded following hand-tight lag screw fixation.

RESULTS

While ankle range of motion increased significantly with creation of the PER-4 injury, under no condition was there a statistically significant change in maximal dorsiflexion angle.

CONCLUSION

Ankle position during distal tibiofibular syndesmosis fixation did not limit dorsiflexion of the ankle joint.

CLINICAL RELEVANCE

Our findings suggest that maximal dorsiflexion during syndesmotic screw fixation may not be necessary.

Correlation of Incisura Anatomy With Syndesmotic Malreduction

BACKGROUND

The anatomy of the syndesmosis is variable, yet little is known on the correlation between differences in anatomy and syndesmosis reduction results. The aim of this study was to analyze the correlation between syndesmotic anatomy and the modes of syndesmotic malreduction.

METHODS

Bilateral postreduction ankle computed tomography (CT) scans of 72 patients treated for fractures with syndesmotic disruption were analyzed. Incisura depth, fibular engagement into the incisura, and incisura rotation were correlated with degree of syndesmotic malreduction in coronal and sagittal planes as well as rotational malreduction.

RESULTS

Clinically relevant malreduction in the coronal plane, sagittal plane, and rotation affected 8.3%, 27.8%, and 19.4% of syndesmoses, respectively. The syndesmoses with a deep incisura and the fibula not engaged into the tibial incisura were at risk of overcompression, anteverted incisuras at risk of anterior fibular translation, and retroverted incisuras at risk of posterior fibular translation.

CONCLUSIONS

Certain morphologic configurations of the tibial incisura increased the risk of specific syndesmotic malreduction patterns.

LEVEL OF EVIDENCE

Level III, comparative study.

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.

3D Model Analysis of Ankle Flexion on Anatomic Reduction of a Syndesmotic Injury

BACKGROUND

The effect of ankle positioning during suture-button fixation for syndesmosis repair on range of motion (ROM) and anatomic reduction has yet to be investigated. The purpose of this cadaveric study was to compare the effects of 3 different ankle positions during suture-button repair on volumetric reduction of the syndesmosis, fibular displacement, and ROM of the ankle using 3-dimensional computed tomography (CT) analysis. The null hypothesis was that ankle position during fixation would not affect syndesmotic volume restoration, fibular displacement, or ROM.

METHODS

Twelve matched pair (n = 24) human cadaveric specimens were used for this study. Prior to syndesmotic sectioning, ROM assessment and CT scans were performed. Following sectioning of the syndesmosis, specimens were repaired in plantarflexion, dorsiflexion, or neutral, and simulated postrepair ROM evaluations and CT scans were repeated. Least squares mean differences between repair groups and the preinjury state were compared by analysis of variance and Tukey's method.

RESULTS

There were no significant differences between repair groups for volumetric reduction ( P = .917), fibular displacement (anterior-posterior, P = .805; medial-lateral, P = .949), or dorsiflexion capacity ( P = .249). Among all specimens, compared with the preinjury state, there was a significant mean ± SD volume reduction of 337 ± 400 mm³ and medial displacement of 1.9 ± 1.5 mm.

CONCLUSION

This study failed to reject the null hypothesis and demonstrated that ankle flexion at the time of syndesmotic fixation with a suture-button construct had no significant in vitro effect on volume changes, fibular displacement, or dorsiflexion capacity. However, in comparison to the preinjured state, suture-button repair resulted in significant overcompression with respect to syndesmosis volume and medial displacement of the fibula.

CLINICAL RELEVANCE

Ankle position at the time of syndesmotic fixation did not affect overall ankle ROM when using a suture-button construct; however, overcompression was observed in all positions. The clinical impact of syndesmotic overcompression remains largely unknown.