Is It Possible to Overcompress the Syndesmosis?

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.

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

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

Clinical outcomes of an olive wire and external fixator versus a metallic screw in the treatment of inferior tibiofibular syndesmosis injuries in ankle fractures

BACKGROUND

Metal screws are the most widely used in treating syndesmotic injuries, but failure and the rigidity of the screws can threaten the success of the treatment and increase the cost of care. We have provided an alternative with an olive wire and external fixator(OWEF) used for syndesmotic fixation.

METHODS

A retrospective longitudinal follow-up study was conducted. From February 2011 to January 2018, 58 of 72 patients with ankle fractures and associated syndesmotic disruption were treated with either screw or OWEF fixation. The costs, complications, and clinical outcomes using Olerud-Molander score and Visual Analog score in screw and OWEF fixation group were compared.

RESULTS

We found the severity of the injury, BMI of the patients and the different fixation methods were determinants of the complications and clinical outcomes. But if no malreduction of the syndesmosis was present, no difference in clinical result was detected.

CONCLUSION

The OWEF method appeared to be at least equally functional and effective to screw fixation while maintaining possible lower complication rate.

LEVELS OF CLINICAL EVIDENCE

Level 3.

In Vivo Syndesmotic Motion After Rigid and Flexible Fixation Using 4-Dimensional Computerized Tomography

INTRODUCTION

Maintaining reduction after syndesmotic injury is crucial to patient function; however, malreduction remains common. Flexible suture button fixation may allow more physiologic motion of the syndesmosis compared with rigid screw fixation. Conventional syndesmotic imaging fails to account for physiologic syndesmotic motion with ankle range of motion (ROM), providing misleading results. Four-dimensional computerized tomography (4DCT) can image joints through a dynamic ROM. Our purpose was to compare syndesmotic motion after rigid and flexible fixation using 4DCT.

METHODS

We analyzed 13 patients with syndesmotic injury who were randomized to receive rigid (n = 7) or flexible (n = 6) fixation. Patients underwent bilateral ankle 4DCT while moving between ankle dorsiflexion and plantar flexion. Measures of syndesmotic position and rotation were extracted from 4DCT to determine syndesmotic motion as a function of ankle ROM.

RESULTS

Uninjured ankles demonstrated significant decreases in syndesmotic width of 1.0 mm with ankle plantar flexion (SD = 0.6 mm, P < 0.01). Initial rigid fixation demonstrated reduced motion compared with uninjured ankles in 4 of 5 measures (P < 0.01) despite all patients in the rigid fixation group having removed, loose, or broken screws by the time of imaging. Rigid fixation led to less motion than flexible fixation in 3 measures (P = 0.02-0.04). There were no observed differences in syndesmotic position or motion between flexible fixation and uninjured ankles.

CONCLUSION

Despite the loss of fixation in all subjects in the rigid fixation group, initial rigid fixation led to significantly reduced syndesmotic motion. Flexible fixation recreated more physiologic motion compared with rigid fixation and may be used to reduce rates of syndesmotic malreduction.

LEVEL OF EVIDENCE

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

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.

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.

Acute and Chronic Syndesmotic Instability: Role of Surgical Stabilization

Acute and chronic syndesmotic injuries significantly impact athletic function and activities of daily living. Patient history, examination, and judicious use of imaging modalities aid diagnosis. Surgical management should be used when frank diastasis, instability, and/or chronic pain and disability ensue. Screw and suture-button fixation remain the mainstay of treatment of acute injuries, but novel syndesmotic reconstruction techniques hold promise for treatment of acute and chronic injuries, especially for athletes. This article focuses on anatomy, mechanisms of injury, diagnosis, and surgical reduction and stabilization of acute and chronic syndesmotic instability. Fixation methods with a focus on considerations for athletes are discussed.

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

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.