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

Comparison of Ankle Fracture Fixation Using Intramedullary Fibular Nailing Versus Plate Fixation

Ankle fracture fixation using intramedullary fibular (IMF) nails has been shown to allow for earlier weightbearing, reduced wound complications, better union rates, and the absence of prominent hardware, compared to plates/screw (PS) constructs. The purpose of present retrospective cohort study was to compare outcomes of patients who underwent ankle fracture fixation using an IMF nail versus PS. Demographic, clinical, and radiographic data were recorded for patients who underwent ankle fracture fixation between May 2020 and May 2022, and who were at least 1 year postoperative. Toe-touch weightbearing was permitted immediately after surgery, protected weightbearing (PWB) at postoperative week 2, and weightbearing as tolerated in a brace at week 6. Radiographs were assessed preoperatively, and at 2, 6, 12, 24, and 48 weeks postoperative. Sixty-one ankle fractures (30 IMF, 31 PS) with a mean follow up of 14.7 and 18 (range, 12 to 23) months were included. Overall, the IMF nail cohort had less pain, faster time to union (11.4 vs 13.2 weeks), and less complications (23% vs 45%), reoperations (10% vs 16%), and surgical failures (9% vs 9.7%), compared to the PS cohort. The differences were not statistically significant. The PS cohort had a higher rate of symptomatic hardware irritation (p =< .001). Tobacco use adversely effected direct osseous healing (p < .001) and increased postoperative complications (p = .050). The present study lends credence to the previously reported advantages of IMF nailing over PS fixation for ankle fractures. Ankle fracture fixation using a fourth generation, IMF nail is a viable alternative to traditional PS fixation.

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 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.

Suture button fixation method used in the treatment of syndesmosis injury: A biomechanical analysis of the effect of the placement of the button on the distal tibiofibular joint in the mid-stance phase with finite elements method

PURPOSE

The purpose of this study is to research the effect of suture button (SB) fixation, a method used at the treatment of ankle syndesmosis injury, which was applied in various angles, pretension force, and levels, on the distal tibiofibular joint (DTFJ) in the mid-stance phase, with the help of three-dimensional finite elements method (FEM) METHOD: The ankle of a healthy individual was digitally analyzed by a finite element method-based package computer program. Then, anterior inferior tibiofibular ligament (AITFL), interosseous ligament, posterior inferior tibiofibular ligament (PITFL) and deltoid ligament (DL) were cut and force and rotation has been applied to the proximal tibia, resulting in syndesmosis injury. Then, various suture button applications on the injured model have been analyzed. Three parameters have been changed; which were divergence in the axial plane (20°, 30°, 40°), distance from the ankle (2, 3, 4 cm), and pretension force (200, 300, 600 N) RESULTS: As the result of this study, the rotation, change in the gap between the distal tibia and distal fibula, and the displacements of the fibula in the x and y axes have been obtained, and numerical results were evaluated. As the force increased, rotation, change in the gap between the distal tibia and distal fibula, and the displacements of the fibula decreased. As suture button application rotation increased, change in the gap between the distal tibia and distal fibula, and displacements of the fibula increased. As the distance from the ankle increases and reaches a certain level, the results converge to those of the healthy model; in the proximal, it diverges from healthy results.

CONCLUSION

In the study, it has been shown that abnormal tibiofibular joint movements can be prevented with suture button application, and optimum application parameters (divergence in the axial plane, distance from the ankle, and pretension force) are given for proper reduction.

The Effect of Syndesmotic Screw Level on Postoperative Syndesmosis Malreduction

Tibiofibular injury repair of ankle fractures may result in over-compression when performed via a partially threaded screw depending on its placed level. We aimed to examine the relationship between the screw level relative to the tibiotalar joint and syndesmosis malreduction in postoperative radiographs of ankle fractures treated with partially threaded screws. We retrospectively analyzed 129 patients who underwent surgery due to lateral malleolar fractures between 2011 and 2019. We measured the distance between the screw and the tibiotalar joint and stratified the patients per their screw level as either trans-syndesmotic or suprasyndesmotic. According to Lauge-Hansen, 83 cases were supination-external rotation type (64.3%), and the remaining were pronation-external rotation type (35.7%) injuries. We found postoperative syndesmosis malreduction in 20 cases (15.5%). Eight (6.2%) cases had medial clear space mismatch. As the distance of the screw to the joint increased, postoperative medial clear space values increased (rho: 0.190, p = .031). The relationship between postoperative syndesmosis mismatch and the level of the syndesmotic screw was statistically significant (p = .044). In syndesmosis repair with a partially threaded screw, as the distance of the screw from the joint increases, the over-compression caused by the screw may cause an increase in postoperative syndesmotic malreduction rates.

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.