Flexible stabilization of the distal tibiofibular syndesmosis: clinical and biomechanical considerations: a review of the literature

Better outcomes using suture button compared to screw fixation in talofibular syndesmotic injuries of the ankle: a level I evidence-based meta-analysis

INTRODUCTION

The present meta-analysis evaluated current level I clinical trials which compared the use of a suture button (SB) versus syndesmotic screw (SS) fixation techniques for syndesmosis injuries of the ankle. The outcomes of interest were to compare patient-reported outcome measures (PROMs) and complications. It was hypothesised that SB might achieve better PROMs along with a lower rate of complications.

METHODS

This study was conducted according to the 2020 PRISMA statement. In August 2023, PubMed, Web of Science, Google Scholar, and Embase were accessed. All the randomised controlled trials (RCTs) which compared SB versus SS fixation for syndesmosis injuries of the ankle were accessed. Data concerning the American Orthopaedic Foot & Ankle Society (AOFAS), and Olerud-Molander score (OMS) were collected at baseline and at last follow-up. Data on implant failure, implant removal, and joint malreduction were also retrieved.

RESULTS

Data from seven RCTs (490 patients) were collected. 33% (161 of 490) were women. The mean length of the follow-up was 30.8 ± 27.4 months. The mean age of the patients was 41.1 ± 4.1 years. Between the two groups (SB and SS), comparability was found in the mean age, and men:women ratio. The SS group evidenced lower OMS (P = 0.0006) and lower AOFAS (P = 0.03). The SS group evidenced a greater rate of implant failure (P = 0.0003), implant removal (P = 0.0005), and malreduction (P = 0.04).

CONCLUSION

Suture button fixation might perform better than the syndesmotic screw fixation in syndesmotic injuries of the ankle.

Clinical and Biomechanical Outcomes of Suture Button Fixation for Ligamentous Lisfranc Injury: A Systematic Review and Meta-analysis

Background

Flexible ligamentous fixation has increased in popularity for the treatment of ligamentous Lisfranc injury, but the optimal fixation strategy is unclear.

Purpose

To review the biomechanical, clinical, and radiographic results of ligamentous Lisfranc injuries treated with flexible fixation.

Study Design

Systematic review; Level of evidence, 4.

Methods

A systematic literature review was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The PubMed/Medline and Google Scholar literature databases were queried for clinical and biomechanical (cadaveric) studies relating to flexible fixation of ligamentous Lisfranc injury. Outcomes of interest included patient-reported outcome scores, clinical/biomechanical results, radiographic alignment, and return to activity. Where appropriate, meta-analysis of the postoperative outcomes was performed.

Results

Of the 34 initial studies, 14 articles (243 feet) were included in the analysis. In the 11 clinical studies (216 patients), the mean postoperative American Orthopaedic Foot & Ankle Society score was 90.1 (n = 150; 6 studies) and the mean visual analog scale score was 1.5 (n = 137; 5 studies). The rate of return to activity was 100% (n = 35; 5 studies), and 100% of patients maintained radiographic alignment postoperatively (n = 62; 6 studies). No complications or subsequent hardware removals were reported. Of the 3 biomechanical studies (27 feet), 1 study found significantly greater change in diastasis under axial load between intact and postfixation ligaments with suture button versus screw fixation (+1.1 vs -0.1 mm; P < .05), another found no difference in the decrease in diastasis under axial load between the injured state and screw or suture button fixation (1.2 vs 1.0 mm; P = .5), and the third found no difference in displacement between intact and either screw or suture button fixation under either axial (intact vs screw: 1.0 vs 2.0 mm, P = .1; intact vs suture button: 0.6 vs 1.8 mm, P = .1) or abduction (intact vs screw: 1.5 vs 1.1 mm, P = .5; intact vs suture button: 1.3 vs 2.1 mm, P = .1) load.

Conclusion

Flexible fixation use in the treatment of ligamentous Lisfranc injury was found to have significant potential as a fixation option, as demonstrated by excellent clinical results. Biomechanical evidence was inconclusive but suggested a trend toward decreased diastasis in specimens fixed with screws compared with suture buttons.

A comparison of double single suture-button fixation, suture-button fixation, and screw fixation for ankle syndesmosis injury: A retrospective cohort study

Different methods have been used throughout the years for syndesmotic injury but there is no consensus on the ideal treatment. Some methods are expensive and some have more complications. The aim of this study is to compare single suture endobutton with double suture endobutton and screw fixation for syndesmotic injury.Sixty nine patients with syndesmotic injury with fibular fractures whom were treated with a single interosseous suture endobutton system (ZipTightTM, Zimmer Biomet), a double interosseous suture endobutton system (ZipTightTM, Zimmer Biomet) and 1 syndesmotic screw (TST, Istanbul, Turkey) were included in this study. Functional and radiological results from patient records between 2015 and 2018 were retrospectively evaluated.Twenty patients were treated with the double interosseous suture endobutton, 23 were treated with the single interosseous suture endobutton, and 26 were treated with traditional AO screw fixation. Three patients from the screw fixation group (11.5%) required revision surgery (P < .05). All the radiologic and clinical outcomes were statistical similar in all 3 groups.Our findings showed that the interosseous suture endobutton system is at least as safe as the screw fixation technique for treatment of syndesmosis joint injuries and can be used as an alternative to the screw method. The interosseous suture endobutton system eliminates the need for a second surgery to remove the hardware, which minimizes the probability of re-diastasis. Since our results showed no statistical difference between single and double interosseous suture endobutton systems, the less costly single endobutton system may be the better alternative.

Biomechanical Analysis of a Novel Syndesmotic Plate Compared With Traditional Screw and Suture Button Fixation

Many lateral malleolus fractures have been found to have syndesmosis injuries after anatomic reduction. The main methods for the treatment of syndesmosis injuries are screw fixation and suture-button flexible fixations. In pursuit of innovation, we have designed a novel syndesmotic plate (NSP) for simultaneous fixation of lateral malleolus fractures and distal tibiofibular syndesmosis injuries. The purpose of this study is to compare the biomechanical characteristics of the NSP to syndesmotic screw and suture-button fixations. Twelve adult cadaveric specimens were used in this experiment. Axial loading as well as rotation torque were applied in 3 different ankle positions: neutral, dorsiflexion, and plantarflexion. After the initial specimens were tested, they were made into a pronation-abduction III fracture model as described by Lauge-Hansen. Subsequently, the specimens were fixed sequentially using a distal fibular anatomic locking plate (DFALP) combined with syndesmotic screws, DFALP combined with suture button, and NSP. Then the above tests were repeated. The syndesmotic displacement and the strain of the tibia and fibula were recorded during the experiment. In most cases, the displacements and strains of the NSP group and the screw group were smaller than the suture button groups and the native (SBGAN) (p < .05), and the displacements and strains of the NSP group were also slightly smaller than the screw group in most cases, and there was no significant difference between the 2 groups. The NSP we developed has a fixed strength no less than the traditional syndesmotic screw fixation. This provides us a new idea for the treatment of distal tibiofibular syndesmosis injuries.

Motion of the distal tibiofibular syndesmosis under different loading patterns: A biomechanical study

PURPOSE

The distal tibiofibular syndesmosis is an important structure for ankle stability. The objective of this study was to evaluate the motion of the syndesmosis under different loading patterns and determine the characteristics of the syndesmotic motion.

METHODS

Six fresh cadaveric lower extremity specimens with the knee reserved were tested in this study. The skin and muscles were removed with all ligaments around the syndesmosis and knee and ankle joint intact. An axial load of 600 N was applied to the specimens with the ankle joint in 10° dorsiflexion, neutral position, and 15° plantar flexion using a universal material testing machine. Then, with the ankle joint positioned neutrally, a combination of 600-N axial and 5-Nm torsional external rotation loading was applied to the specimens. The medial-lateral and anterior-posterior displacement and rotation of the distal fibula relative to the distal tibia were measured.

RESULTS

Under the axial loading, the distal fibula tended to move medially and anteriorly and rotate internally with the ankle positioned from the neutral position to 15° plantar flexion. Meanwhile, when the ankle was positioned from the neutral position to 10° dorsiflexion, the distal fibula tended to move laterally and posteriorly and rotate externally. Under the combined loading, with respect to the isolated axial loading, the distal fibula tended to move medially and posteriorly, and rotate externally relative to the distal tibia.

CONCLUSION

Micro motion existed in the syndesmosis. The relative motion of the syndesmosis was correlated to the ankle position and loading patterns.

Syndesmotic Fixation With Suture Button: Neurovascular Structures at Risk: A Cadaver Study

OBJECTIVES

The objective of this study was to describe the anatomic variations in the saphenous nerve and risk of direct injury to the saphenous nerve and greater saphenous vein during syndesmotic suture button fixation.

METHODS

Under fluoroscopic guidance, syndesmotic suture buttons were placed from lateral to medial at 1, 2, and 3 cm above the tibial plafond on 10 below-knee cadaver leg specimens. The distance and position of each button from the greater saphenous vein and saphenous nerve were evaluated.

RESULTS

The mean distance of the saphenous nerve to the suture buttons at 1, 2, and 3 cm were 7.1 ± 5.6, 6.5 ± 4.6, and 6.1 ± 4.2, respectively. Respective rate of nerve compression was as follows, 20% at 1 cm, 20% at 2 cm, and 10% at 3 cm. Mean distance of the greater saphenous vein from the suture buttons at 1, 2, and 3 cm was 8.6 ± 7.1, 9.1 ± 5.3, and 7.9 ± 4.9 mm, respectively. Respective rate of vein compression was 20%, 10%, and 10%. A single nerve branch was identified in 7 specimens, and 2 branches were identified in 3 specimens.

CONCLUSION

There was at least one case of injury to the saphenous vein and nerve at every level of button insertion at a rate of 10% to 20%. Neurovascular injury may occur despite vigilant use of fluoroscopy and adequate surgical technique. Further investigation into the use of direct medial visualization of these high-risk structures should be done to minimize the risk. Levels of Evidence: Therapeutic, Level II: Prospective, comparative study.

Dynamic Fixation versus Static Fixation in Treatment Effectiveness and Safety for Distal Tibiofibular Syndesmosis Injuries: A Systematic Review and Meta-Analysis

To compare the effectiveness and safety of dynamic fixation (DF) and static fixation (SF) in distal tibiofibular syndesmosis injuries (DTSI) by a system review and meta-analysis. PubMed, Cochrane, and EMBASE were systematically searched by computer to select clinical randomized controlled trials (RCT) and cohort trials comparing DF and SF in treating patients with DTSI. RCT and cohort trials comparing DF and SF for patients with DTSI were included. Inclusion criteria: (i) prospective or retrospective study of patients with DTSI; (ii) patients were diagnosed as having DTSI by imageology and only received DF treatment or SF treatment; (iii) the study compared DF and SF in DTSI; and (iv) one or more of the following outcomes were reported: ankle joint functional score, surgical complications, malreduction of syndesmosis, and second operations. Exclusion criteria: (i) non-human studies; (ii) DTSI patients accompanied with other complications or other joints injuries; and (iii) full text unavailable. RevMan V5.3 software was used to perform the statistical analysis. Outcomes analyzed by Revman software showed that there were no statistically significant differences between DF and SF in the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot score (MD, 1.90; 95% CI, -0.23 to 4.03; P = 0.08; I² = 0%), Olerud-Molander (OM) score (MD, 1.92; 95% CI, -7.96 to 11.81; P = 0.70; I² = 55%), incidence of syndesmotic malreduction (RR, 0.19; 95% CI, 0.03 to 1.09; P = 0.06; I² = 0%), and overall postoperative complication rate (RR, 0.30; 95% CI, 0.09 to 0.99; P = 0.05, I² = 75%) and the rate of second procedure was significantly lower with DF (RR, 0.17; 95% CI, 0.07 to 0.43; P = 0.0002, I² = 54%). Compared to SF, DF has an advantage, with a low rate of second procedures to treat DTSI.

Titanium cable isotonic annular fixation system for the treatment of distal tibiofibular syndesmosis injury

Distal tibiofibular syndesmosis injury (DTS) occurs frequently with ankle sprains. Current treatments pose several limitations including causing soft tissue irritation, bringing damage to fixation secondary to weight-bearing, and requiring follow-up surgeries. Here, we investigated the clinical effects of a new technique, titanium cable isotonic annular fixation, for the treatment of DTS injury. From January 2015 to June 2017, 36 patients with ankle fractures and DTS injuries had their fractures repaired with the titanium cable isotonic annular fixation system. Recovery was scored by the AOFAS ankle function score system. We also assessed the differences in ankle motion between healthy and operative joints, and recorded the complications. All patients recovered from surgery without any serious complications. We followed all the cases for 18-25 months with an average follow-up of 21.26±3.23 months. 12 months after the operation, X-ray images showed that the titanium cables were fixed in the correct position without any fracture or loosening. Additionally, no degeneration or traumatic arthritis was observed in the ankle joint. There were no incision or bone mineral density changes between the titanium fix and tibiofibular bones. Nearly all patients recovered well except for three who developed inflammation and infection. However, these three patients recovered following 1 week of intravenous antibiotics and local radiofrequency physiotherapy. According to the AOFAS scoring system, all patients achieved satisfactory recovery 12 months post operation. Our titanium cable isotonic annular fixation system has both the advantages of elastic and rigid fixations. It can restore isotonic strength of the distal tibiofibular joint, and its biomechanical performance approaches normal physiological function. After the operation, patients tolerated weight-bearing exercise and recovered joint mobility. Finally, there is no need to remove the distal tibiofibular implant after 12 weeks. Overall, it is a highly effective surgical method to treat DTS injury.

Changes in the Width of the Tibiofibular Syndesmosis Related to Lower Extremity Joint Dynamics and Neuromuscular Coordination on Drop Landing During the Menstrual Cycle

Background:

Many injuries of the lower extremities, especially the knee and ankle, occur during sports activity, and the incidence rate is higher in women than in men.

Hypothesis:

The hypothesis was that phases of the menstrual cycle affect the width of the tibiofibular syndesmosis during drop landing in healthy young women and that such changes at the tibiofibular joint also affect the dynamics and neuromuscular coordination of the lower extremities.

Study Design:

Descriptive laboratory study.

Methods:

Participants included 28 healthy young women (mean age, 21.0 ± 0.8 years). Blood samples were collected to determine plasma levels of estradiol and progesterone immediately before the performance of the task: drop landing on a single leg from a 30-cm platform. Using ultrasonography, the distance between the tibia and the distal end of the fibula, regarded as the width of the tibiofibular syndesmosis, was measured in an upright position without flexion of the ankle. The peak ground-reaction force (GRF) on landing was measured using a force platform. The time to peak GRF (Tp-GRF) was measured as the time from initial ground contact to the peak GRF. Hip, knee, and ankle joint angles during the single-leg landing were calculated using a 3-dimensional motion analysis system. Muscle activities of the lower extremities were measured using surface electromyography.

Results:

The width of the tibiofibular syndesmosis was significantly greater in the luteal phase when compared with the menstrual, follicular, and ovulation phases (by 5%-8% of control). Also, during the luteal phase, the Tp-GRF was significantly shorter than in the follicular phase (by 6%); hip internal rotation and knee valgus were significantly greater than in the menstrual phase (by 43% and 34%, respectively); knee flexion was significantly less than in the menstrual and follicular phases (by 7%-9%); ankle dorsiflection was significantly less than in the follicular phase (by 11%); ankle adduction and eversion were significantly greater than in the menstrual and follicular phases (by 26%-46%, and 27%-33%, respectively); and activation of the gluteus maximus before landing was significantly lower than in the menstrual and follicular phases (by 20%-22%).

Conclusion:

The luteal phase appears to be associated with decreased strength and laxity of the ankle as well as lower extremity muscle activity in women. The changes presumably represent a greater risk for sports injuries.

Clinical Relevance:

The results of this study suggest that the luteal phase may be related to the greater incidence of lower extremity injuries in women.

Acute syndesmotic instability in ankle fractures: A review

Ankle fractures are among the most common fracture types, and 10% of all ankle fractures lead to accessory syndesmotic injury. An injury that is challenging in every respect is syndesmotic instability. Since the range of diagnostic techniques and the therapeutic options is extensive, it still is a controversial subject, despite the abundance of literature. This review aimed to summarize the current knowledge on syndesmotic instability in ankle fractures and to formulate some recommendations for clinical practice. Chronic instability and the operative osseous treatment of ankle fractures are not part of this review.

Novel anatomical reconstruction of distal tibiofibular ligaments restores syndesmotic biomechanics

PURPOSE

To date, there is a paucity of literature on syndesmotic reconstruction techniques that restore both anatomic stability and physiologic syndesmotic biomechanics. In this cadaveric study, (1) a novel syndesmotic reconstruction surgical technique using autogenous peroneus brevis tendon was described and (2) the biomechanical properties of the reconstruction was investigated.

METHODS

Ten fresh-frozen lower extremities were used in this study. Reconstruction of the anterior and posterior, as well as the interosseous tibiofibular ligaments was performed with a halved peroneus brevis tendon. Biomechanics were assessed using foot external rotation torque and ankle dorsiflexion axial loading tests, which were performed in (a) intact, (b) cut, (c) anatomically reconstructed syndesmotic ligaments, and (d) 3.5 mm tricortical syndesmotic screw fixation. Medial-lateral and anterior-posterior displacements of the distal fibula were recorded during foot external rotation and fibular axial displacement was recorded during ankle axial loading.

RESULTS

The fibula was displaced posteriorly and proximally with respect to the tibia in all specimens during external rotation and axial loading tests, respectively. Significant differences (p < 0.05) were found in distal fibular displacements between anatomically reconstructed ligaments and screw fixation. Tricortical syndesmotic screw fixation resulted in 59% of posterior fibular displacement when compared to intact ligaments. No significant differences (n.s.) in distal fibular displacement were demonstrated between intact ligaments and anatomically reconstructed ligaments.

CONCLUSION

Anatomical reconstruction of the distal tibiofibular ligaments with the peroneus brevis tendon provides stability and recreates the biomechanical properties of an intact syndesmosis. This new surgical technique may be a viable alternative for the treatment of syndesmotic injuries.

LEVEL OF EVIDENCE

V.

Tightrope fixation of syndesmotic injuries in Weber C ankle fractures: a multicentre case series

BACKGROUND

No general consensus has yet been established for the gold standard treatment of ankle syndesmotic complex injuries. Recent literature has documented the success of ankle tightrope fixation for heterogeneous ankle fracture patterns, resulting in syndesmotic complex injuries. We present a multicentre case series assessing the clinical, radiological and functional outcomes of patients with Weber C ankle fractures treated with the Arthrex TightRope^® fixation system.

METHOD

We performed a retrospective analysis of all adult patients with Weber C ankle fractures who were treated with the Arthrex TightRope^® fixation system at four centres over a 3-year period. All patients were followed up for a mean of 14 months (range 12-26). Outcomes measures were assessed subjectively using functional scores (AOFAS and Olerud and Molander) and objectively using radiological measurements, complication rates and revision surgery rates.

RESULTS

Thirty-six patients met our eligibility criteria. The mean age at operation was 31 years (range 18-65). There were 20 males and 16 females. No patients were lost to follow-up. The ankle tightrope maintained satisfactory reduction in the ankle mortise in 97% of cases. Of these 35 successfully treated cases, no evidence of re-displacement on follow-up radiographs of the syndesmotic complex was observed at an average of 10.8 months (range 6-12). Post-operative mean medial clear space was 3.1 mm, and mean tibio-fibular overlap was 10.1 mm. The mean American Orthopaedic Foot and Ankle Society (AOFAS) score was 88.8 (range 67-98) at a mean follow-up of 14 months (range 12-26). The overall complication rate was 6% (one failure requiring revision surgery and one medial sided skin irritation requiring removal of suture button). No infections or wound complications occurred.

CONCLUSION

Tightrope fixation is a safe alternative to screw fixation for syndesmotic complex injuries in Weber C ankle fractures. We have shown that it has low complication rates and a high patient satisfaction.

Suture Button Fixation Versus Syndesmotic Screws in Supination-External Rotation Type 4 Injuries: A Cost-Effectiveness Analysis

BACKGROUND

In stress-positive, unstable supination-external rotation type 4 (SER IV) ankle fractures, implant selection for syndesmotic fixation is a debated topic. Among the available syndesmotic fixation methods, the metallic screw and the suture button have been routinely compared in the literature. In addition to strength of fixation and ability to anatomically restore the syndesmosis, costs associated with implant use have recently been called into question.

PURPOSE

This study aimed to examine the cost-effectiveness of the suture button and determine whether suture button fixation is more cost-effective than two 3.5-mm syndesmotic screws not removed on a routine postoperative basis.

STUDY DESIGN

Economic and decision analysis; Level of evidence, 2.

METHODS

Studies with the highest evidence levels in the available literature were used to estimate the hardware removal and failure rates for syndesmotic screws and suture button fixation. Costs were determined by examining the average costs for patients who underwent surgery for unstable SER IV ankle fractures at a single level-1 trauma institution. A decision analysis model that allowed comparison of the 2 fixation methods was developed.

RESULTS

Using a 20% screw hardware removal rate and a 4% suture button hardware removal rate, the total cost for 2 syndesmotic screws was US$20,836 and the total effectiveness was 5.846. This yielded a total cost of $3564 per quality-adjusted life-year (QALY) over an 8-year time period. The total cost for suture button fixation was $19,354 and the total effectiveness was 5.904, resulting in a total cost of $3294 per QALY over the same time period. A sensitivity analysis was then conducted to assess suture button fixation costs as well as screw and suture button hardware removal rates. Other possible treatment scenarios were also examined, including 1 screw and 2 suture buttons for operative fixation of the syndesmosis. To become more cost-effective, the screw hardware removal rate would have to be reduced to less than 10%. Furthermore, fixation with a single suture button continued to be the dominant treatment strategy compared with 2 suture buttons, 1 screw, and 2 screws for syndesmotic fixation.

CONCLUSION

This cost-effectiveness analysis suggests that for unstable SER IV ankle fractures, suture button fixation is more cost-effective than syndesmotic screws not removed on a routine basis. Suture button fixation was a dominant treatment strategy, because patients spent on average $1482 less and had a higher quality of life by 0.058 QALYs compared with patients who received fixation with 2 syndesmotic screws. Assuming that functional outcomes and failure rates were equivalent, screw fixation only became more cost-effective when the screw hardware removal rate was reduced to less than 10% or when the suture button cost exceeded $2000. In addition, fixation with a single suture button device proved more cost-effective than fixation with either 1 or 2 syndesmotic screws.

A systematic review on dynamic versus static distal tibiofibular fixation

BLACKGROUND

In the last couple of years dynamic fixation for syndesmosis injuries, using a suture-button technique, raised more interest due to its advantages over the static fixation. In the current systematic review suture-button fixation is compared to the traditionally applied static fixation in unstable ankle fractures accompanied with distal tibiofibular syndesmosis injury, including the functional outcome, post-operative complications, reoperation rate, recurrent diastasis and financial aspects.

METHODS

A computerized literature search using PubMed/MEDLINE and EMBASE was conducted in search of suitable articles between January 2006 and February 2016. A total of 4 suture-button studies, 5 suture-button vs. static fixation studies and 1 study discussing the financial aspects were identified.

RESULTS

The AOFAS of 104 patients treated with the suture-button device was 91.08 points with an average study-follow up of 24.85 months. The AOFAS of 106 patients treated with a static fixation device was 87.95 with an average follow-up of 24.78 months. Removal of the suture-button device was reported in 10.5% of 229 patients and removal of the screws in 38.5%.

CONCLUSIONS

Dynamic fixation demonstrated to be a viable alternative to the static fixation device, with lower reoperation rates and less complications. They can accurately stabilize the ruptured syndesmosis without device breakage or loss of reduction.

LEVEL OF EVIDENCE

1A economic/decision.

Real-time three-dimensional digital image correlation for biomedical applications

Digital image correlation (DIC) has been successfully applied for evaluating the mechanical behavior of biological tissues. A three-dimensional (3-D) DIC system has been developed and applied to examining the motion of bones in the human foot. To achieve accurate, real-time displacement measurements, an algorithm including matching between sequential images and image pairs has been developed. The system was used to monitor the movement of markers which were attached to a precisely motorized stage. The accuracy of the proposed technique for in-plane and out-of-plane measurements was found to be ?0.25% and 1.17%, respectively. Two biomedical applications were presented. In the experiment involving the foot arch, a human cadaver lower leg and foot specimen were subjected to vertical compressive loads up to 700 N at a rate of 10??N/s and the 3-D motions of bones in the foot were monitored in real time. In the experiment involving distal tibio fibular syndesmosis, a human cadaver lower leg and foot specimen were subjected to a monotonic rotational torque up to 5 Nm at a speed of 5 deg per min and the relative displacements of the tibia and fibula were monitored in real time. Results showed that the system could reach a frequency of up to 16 Hz with 6 points measured simultaneously. This technique sheds new lights on measuring 3-D motion of bones in biomechanical studies.

Biomechanical Concepts for Fracture Fixation

Application of the correct fixation construct is critical for fracture healing and long-term stability; however, it is a complex issue with numerous significant factors. This review describes a number of common fracture types and evaluates their currently available fracture fixation constructs. In the setting of complex elbow instability, stable fixation or radial head replacement with an appropriately sized implant in conjunction with ligamentous repair is required to restore stability. For unstable sacral fractures with vertical or multiplanar instabilities, "standard" iliosacral screw fixation is not sufficient. Periprosthetic femur fractures, in particular Vancouver B1 fractures, have increased stability when using 90/90 fixation versus a single locking plate. Far cortical locking combines the concept of dynamization with locked plating to achieve superior healing of a distal femur fracture. Finally, there is no ideal construct for syndesmotic fracture stabilization; however, these fractures should be fixed using a device that allows for sufficient motion in the syndesmosis. In general, orthopaedic surgeons should select a fracture fixation construct that restores stability and promotes healing at the fracture site, while reducing the potential for fixation failure.

Economic impact of syndesmosis hardware removal

Ankle syndesmosis injuries are commonly seen with 5-10% of sprains and 10% of ankle fractures involving injury to the ankle syndesmosis. Anatomic reduction has been shown to be the most important predictor of clinical outcomes. Optimal surgical management has been a subject of debate in the literature. The method of fixation, number of screws, screw size, and number of cortices are all controversial. Postoperative hardware removal has also been widely debated in the literature. Some surgeons advocate for elective hardware removal prior to resuming full weightbearing. Returning to the operating room for elective hardware removal results in increased cost to the patient, potential for infection or complication(s), and missed work days for the patient. Suture button devices and bioabsorbable screw fixation present other options, but cortical screw fixation remains the gold standard. This retrospective review was designed to evaluate the economic impact of a second operative procedure for elective removal of 3.5mm cortical syndesmosis screws. Two hundred and two patients with ICD-9 code for "open treatment of distal tibiofibular joint (syndesmosis) disruption" were identified. The medical records were reviewed for those who underwent elective syndesmosis hardware removal. The primary outcome measurements included total hospital billing charges and total hospital billing collection. Secondary outcome measurements included average individual patient operative costs and average operating room time. Fifty-six patients were included in the study. Our institution billed a total of $188,271 (USD) and collected $106,284 (55%). The average individual patient operating room cost was $3579. The average operating room time was 67.9 min. To the best of our knowledge, no study has previously provided cost associated with syndesmosis hardware removal. Our study shows elective syndesmosis hardware removal places substantial economic burden on both the patient and the healthcare system.

Biomechanical comparison of bionic, screw and Endobutton fixation in the treatment of tibiofibular syndesmosis injuries

BACKGROUND

The two prevalent fixation methods in the treatment of syndesmosis injuries, the rigid screw fixation and flexible Endobutton fixation, are not without issues; thus, we have designed a novel bionic fixation method which combines the features of both rigid and flexible fixations. The aim of this study was to compare the biomechanical properties of the bionic fixation to the screw and Endobutton fixations.

METHODS

Six normal fresh-frozen legs from amputation surgery were used. After initial tests of intact syndesmosis, screw, bionic and Endobutton fixations were performed sequentially for each specimen. Axial loading as well as rotation torque were applied, in five different ankle positions: neutral position, dorsiflexion, plantar flexion, varus, and valgus. The displacement of the syndesmosis and the tibial strain were analysed using a biomechanical testing system.

RESULTS

Whether receiving axial loading or rotation torque, in most situations (neutral position, dorsiflexion, varus, plantar flexion with low loading, valgus with high loading, internal and external rotation), the bionic group and Endobutton group had comparable displacements, and there was no significant difference among the intact, bionic, and Endobutton groups; whereas the displacements of the screw group were smaller than any of the other three groups. Results of the tibial strain were similar with that of the displacement.

CONCLUSIONS

The bionic fixation at least equals the performance of Endobutton fixation; it also allows more physiologic movement of the syndesmosis when compared to the screw fixation and may serve as a viable option for the fixation of the tibiofibular syndesmosis.

Assessment of Anatomic Risk During Syndesmotic Stabilization With the Suture Button Technique

The suture button technique represents an accepted method of fixation for acute or chronic injury to the tibiofibular syndesmosis. The objective of the present investigation was to assess the anatomic risk to the superficial medial neurovascular structure with insertion of a syndesmotic suture button and to measure the distance of the button to the greater saphenous vein during a standardized insertion. A syndesmotic suture button was inserted with a standardized technique in 20 fresh frozen cadaveric limbs. Of 20 suture buttons, 14 (70.0%) were inserted posterior to the greater saphenous vein, 2 (10.0%) were inserted anterior to the greater saphenous vein, and 4 (20.0%) were inserted directly onto the greater saphenous vein. A total of 11 suture buttons (55.0%) were inserted with some entrapment of a medial neurovascular structure. The absolute mean ± standard deviation distance of the suture button to the greater saphenous vein was 4.88 ± 4.44 mm. The results of the present investigation have indicated that a risk of entrapment of superficial medial neurovascular structures exists with insertion of a suture button for syndesmotic fixation and that a medial incision should be used to ensure that structures are not entrapped.

Gender difference in distance of tibiofibular syndesmosis to joint dynamics of lower extremities during squat

The incidence of lower extremity injury is greater in women than men, indicating gender difference in lower extremity function. Here we investigate the role of the ankle during squatting in young men and women by measuring the tibiofibular syndesmosis (TFS) distance and the angles of hip, ankle and knee joints. TFS distance was positively correlated to body mass in men, but not in women, suggesting some factor(s) affecting TSF distance in women. When divided into two groups with wide and narrow TFS distances, men apparently used ankle and hip joints evenly during squatting, but women, specifically those with a narrow TFS distance, used the hip joint more effectively than ankle. Estimated knee moment was positively correlated to TFS distance in women, but not in men. These results suggest that the women possessing a wider TFS distance use ankle function rather than hip junction when performing lower-extremity exercises (i.e. squatting), presumably accounting for the higher incidence of ankle injury in women during such activities.

Lagged Syndesmotic Fixation: Our Clinical Experience

Ankle fractures are very common, and although algorithms are in place for osseous management, consensus has not been reached regarding treatment of associated ligamentous injuries. Although tibiofibular syndesmotic stabilization can be done using different forms of fixation, the biomedical literature has long emphasized the risk of long-term restriction of ankle mobility with the use of lagged transfixation. However, when reduction cannot be maintained with positional fixation, we found that lagging the syndesmotic screw helped to maintain the reduction without causing functional restriction. In this report, we describe our experience with patients who had undergone lagged tibiofibular transfixation and were available for short- to intermediate-term follow-up to assess ankle function. A total of 31 patients (32.63% of 95 consecutive patients) were available at a mean of 34.87 (range 18 to 52) months to complete the American Orthopedic Foot and Ankle Society ankle-hindfoot questionnaire. The mean score was 88.38 (range 42 to 100) points at a mean follow-up interval of 34.87 (range 18 to 52) months. Of 31 patients, 19 had an AOFAS score of 90 points, 9 an AOFAS score of 80 to 89 points, 2 an AOFAS score of 60 to 69 points, and 1 an AOFAS score of <60 points. Because all syndesmotic screws were placed using the lag technique, unrestricted motion compared with the uninjured limb was used as the endpoint. All subjects had unrestricted motion compared with the uninjured limb, refuting the assertion that lagged syndesmotic screw fixation confers more restriction in ankle kinematics than positional syndesmotic fixation.

A modified technique for fixation of chronic instability of the distal tibiofibular syndesmosis using a wire and button

Distal tibiofibular syndesmosis injury accounts for 1% to 11% of soft tissue injuries of the ankle. Some acute syndesmotic injuries will fail to heal effectively owing to inadequate treatment or misdiagnosis, eventually resulting in chronic instability, which can destroy the stability of the ankle joint. Various surgical techniques have been described for fixation of the syndesmosis. Among the existing methods, the suture button has the advantage of allowing for physiologic micromotion at the syndesmosis by maintaining the reduction and preventing the risk of screw breakage. However, the "relatively" long suture between buttons can gradually relax under continuous loading, resulting in fixation failure, which we have termed electric wire phenomenon. In the present report, we have described a modified technique for flexible fixation using the Endobutton CL ULTRA fixation device by tricortical fixation, instead of quadricortical fixation, to allow for robust and reliable fixation of the distal tibiofibular syndesmosis. The modified technique is devoid of the concern regarding the use of screw fixation and can reduce the risk of displacement or elongation and skin irritation associated with the suture button.

Internal fixation of distal tibiofibular syndesmotic injuries: a systematic review with meta-analysis

No consensus had been reached about the optimal method for syndesmotic fixation. The present study analysed syndesmotic fixation based on the highest level of clinical evidence in order to obtain more reliable results. Medline, Embase and Cochrane database were searched through the OVID retrieval engine. Manual searching was undertaken afterward to identify additional studies. Only randomized controlled trials (RCT) and prospective comparative studies were selected for final inclusion. Study screening and data extraction were completed independently by two reviewers. All study characteristics were summarized into a table. The extracted data were used for data analysis. Twelve studies were finally included: six of them were RCTs, two were quasi-randomized studies and four were prospective comparative studies. Four comparisons with traditional metallic screw were identified in terms of bioabsorbable screws, tricortical fixation method, suture-button device as well as non-fixation choice in low syndesmotic injuries. Both absorbable screws and the tricortical fixation method showed almost no better results than traditional quadricortical metallic screw (p > 0.05). Additionally, existing studies could not illustrate their efficiency of reducing hardware removal rate. The suture button technique had significantly better functional score (p = 0.003), ankle motion (p = 0.02), time to full weightbearing (p < 0.0001) and much less complications (p = 0.0008) based on short and intermediate term follow-up data. Transfixation in low syndesmotic injuries showed poorer results than the non fixed group in all outcome measurements, but didn't reach a significant level (p > 0.05). The present evidence still couldn't find superior performance of the bioabsorbable screw and tricortical fixation method. Their true effects in decreasing second operation rate need further specific studies. Better results of the suture-button made it a promising technique, but it still needs long-term testing and cost-efficiency studies. The patients with low syndemotic injuries should be well assessed before fixation determination and the indication of screw placement in such conditions needs to be further defined.