Changes in the syndesmotic reduction after syndesmotic screw fixation for ankle malleolar fractures: One-year longitudinal evaluations using computer tomography

IntroductionTo evaluate time-dependent changes in the syndesmotic reduction after syndesmotic screw fixation and one year after screw removal for ankle malleolar fractures, and to assess whether the incidence of syndesmotic malreduction changes depending on the measurement method.MethodsWe assessed twenty patients who underwent syndesmotic screw fixation for ankle fractures. The syndesmotic screws were removed after six weeks of the fracture surgery. Syndesmotic reduction was assessed within two weeks of the fracture surgery and one year after the screw removal using the axial computer tomographic images. Side-to-side differences in the anterior and posterior tibiofibular distances, anteroposterior fibular translation, and fibular rotation were measured.ResultsThe mean anterior tibiofibular distance was 0.7 mm after syndesmotic fixation. It increased to 1.9 mm at one year after screw removal (p = 0.002). After syndesmotic fixation, four ankles had malreduction of the anterior tibiofibular distance, including three ankles with widening and one with overtightening. At one year, eight ankles had malreduction, all of whom had widening. The other measurement values did not change over time (0.1 mm vs. 0.6 mm for the posterior tibiofibular distance, 0.2 mm vs. 0.3 mm for the anteroposterior fibular translation, and 0.7 ° vs. 0 ° for the fibular rotation). The incidences of malreduction were significantly different depending on the definition of malreduction, ranging from 10% to 50% after syndesmotic fixation (p = 0.01) and from 20% to 60% at one year after screw removal (p = 0.02).ConclusionsThe anterior tibiofibular distance widened after one year of syndesmotic screw removal. The incidence of malreduction varied depending on the measurement method.     

Cost analysis of ankle syndesmosis internal fixation

BackgroundUnstable ankle syndesmosis injuries are common, and the optimal surgical fixation is controversial. The two main options for stabilization of syndesmotic injuries are suture button fixation and screw fixation. Suture button fixation has a higher initial cost, but may have a lower hardware removal rate. The purpose of this study was to compare the costs of syndesmotic fixation.MethodsA cost analysis was performed at a single university-affiliated hospital. Variables included the number of suture buttons, the number and type of syndesmosis screws used, and the frequency of hardware removal and operative time required for hardware removal. There were four clinical scenarios evaluated: (A) one suture button versus one cortical screw; (B) two suture buttons versus two cortical screws; (C) one suture button versus one locking screw; (D) two suture buttons versus two locking screws. Suture button removal rate was assumed to be 0% in the analysis.ResultsCost equivalence was achieved at an 18 to 53% syndesmotic screw removal rate depending on the fixation construct used and the amount of time required for hardware removal. When the syndesmosis screws were removed 100% of the time, suture button fixation was more economical by $85,000–$194,656 per 100 ankles. When hardware was never removed, suture button fixation was more expensive by $169,844–$295,500 per 100 ankles.ConclusionThis study demonstrates that the costs associated with syndesmosis fixation are more dependent on the rate of hardware removal than the type of hardware utilized. Routine removal of syndesmosis screws is clearly less economical than suture button fixation.     

Predisposing factors for chronic syndesmotic instability following syndesmotic fixation in ankle fracture: Minimum 5-year follow-up outcomes

BackgroundThis study aimed to identify risk factors for chronic syndesmotic instability following syndesmotic fixation.MethodsWe performed a retrospective review of consecutive patients who had sustained ankle fractures requiring syndesmotic fixation. Patients available for a minimum 5 years of follow-up were classified into 2 groups according to the presence of syndesmotic instability. Statistical binary logistic regression analyses were performed to investigate the significance of various risk factors. Functional outcomes were assessed using the FAOS.ResultsIn total, 166 patients who met the study inclusion criteria underwent analysis. The overall postoperative instability rate was 20.5%, which was significantly affected due to BMI (p = 0.018; OR 6.72), and concomitant posterior malleolar fracture (p = 0.032, OR 2.77). The mean scores in the syndesmotic instability (SI) group were significantly lower than those in the no syndesmotic instability (NSI) group (p = 0.021).ConclusionsObesity and concomitant posterior malleolar fracture were significant risk factors for postoperative syndesmotic instability.     

Technical aspects of the syndesmotic screw and their effect on functional outcome following acute distal tibiofibular syndesmosis injury

Introduction

Much of the currently available data on the technical aspects of syndesmotic screw placement are based upon biomechanical studies, using cadaveric legs with different testing protocols, and on surgeon preference. The primary aim of this study was to investigate the effect of the level of syndesmotic screw insertion on functional outcome. Further, the effects of number of cortices engaged, the diameter of the screw, use of a second syndesmotic screw and the timing of removal on functional outcome were tested.

Material and method

All consecutive patients treated for an ankle fracture with concomitant acute distal tibiofibular syndesmotic injury that had a metallic syndesmotic screw placed, between 1 January 2004 and 31 December 2010, were included. Patient characteristics (i.e., age at injury and gender), fracture characteristics (i.e., affected side, trauma mechanism, Weber fracture type and number of fractured malleoli), and surgical characteristics (i.e., level of screw placement, screw diameter, tri- or quadricortical placement, number of syndesmotic screws used and the timing of screw removal) were recorded. Outcome was measured using validated questionnaires, which were sent by post, and consisted of the American Orthopaedic Foot and Ankle Society ankle-hindfoot score (AOFAS), the Olerud–Molander Ankle Score (OMAS) and a single question Visual Analog Scale (VAS) for patient satisfaction with outcome.

Results

During the 7-year study period, 122 patients were treated for syndesmotic injury. A total of 93 patients (76%) returned the questionnaire. The median follow-up was 51 months. The outcome scoring systems showed an overall score for the entire group of 92 points for the AOFAS, 77 for the OMAS and 8.2 for the VAS. Outcome was statistically significantly influenced by the number of fractured malleoli, age, trauma mechanism and the level of screw insertion.

Conclusion

Overall, the functional outcome of acute syndesmotic injuries treated with a syndesmotic screw was good and mainly influenced by patient and fracture characteristics. Most different technical aspects of placement appeared not to influence these results. Only screw placement above 41 mm negatively influenced outcome.     

Biomechanical comparison of suture-button,bioabsorbable screw,and metal screw for ankle syndesmotic repair: A meta-analysis

BackgroundTo compare biomechanically metal screw fixation to suture-button or bioabsorbable screw fixation for ankle syndesmotic injuries.MethodsA literature search of the comparison studies in Pubmed and Google Scholar was conducted. The biomechanical outcomes of interest were syndesmotic stability in the coronal, sagittal, and axial planes as well as torque and rotation at failure.ResultsA total of 11 cadaveric studies were included. In the suture-button group, coronal displacement (MD 1.72 mm, p = 0.02) and sagittal displacement (MD 2.65 mm, p = 0.0003) were increased relative to the metal screw group. In contrast, no difference was found with axial rotation (MD 0.35 degrees, p = 0.57). Bioabsorbable screws exhibited equivalent failure torque (MD ?3.04 Nm, p = 0.53) and rotation at failure (MD 3.77 degrees, p = 0.48) in comparison to metal screws.ConclusionsSuture-button provide less rigidity when compared to metal screw fixation. They afford flexible syndesmotic micromotion which may more closely resemble a physiological state and be helpful for ligament healing. Bioabsorbable screws demonstrate similar mechanical strength properties to metal screws.     

A cadaveric study investigating the role of the anterior inferior tibio-fibular ligament and the posterior inferior tibio-fibular ligament in ankle fracture syndesmosis stability

BackgroundThis cadaveric study aimed to investigate the role AITFL and PITFL have on preventing talar shift in ankle fractures, as well as investigating the role of AITFL reconstruction in preventing talar shift.MethodsTwelve lower limb cadavers were used. Talar shift was measured following: Step 1- no ligaments cut; Step 2- entire deltoid ligament division; Step 3- group A (5 specimens) PITFL cut whilst group B (7 specimens) AITFL cut; Step 4- group A had AITFL divided whilst group B had PITFL cut. Reconstruction of the AITFL was performed using part of the superior extensor retinaculum as a local flap. Measurement of talar shift was then repeated.ResultsWith no ligaments divided, mean talar shift was 0.8 mm for group A and 0.7 mm for group B. When the deltoid ligament was divided, mean talar shift for group A was 4.8 mm compared to 4.7 mm in group B (P = 1.00). The mean shift in group A after PITFL division was 6.0 mm, increasing the talar shift by an average of 1.2 mm. In group B after AITFL division mean talar shift was 8.3 mm (P = 0.06), increasing talar shift by an average of 3.6 mm. After division of the second tibiofibular ligament, mean talar shift in group A measured 10.0 mm and in group B was 10.9 mm (P = 0.29). Three times more talar shift occurred after the AIFTL was divided compared to the PITFL (P = 0.06).ConclusionConsequently, repairing the PITFL in isolation (for example by fixation of a posterior malleolus avulsion fracture) may not adequately prevent talar shift; we feel consideration should also be given to reconstruction of the AITFL to augment the syndesmosis fixation, which may provide a stronger restoration of ankle stability.Level of Clinical Evidence: 5.     

三角韧带与下胫腓联合韧带对踝关节稳定的生物力学影响

目的探讨三角韧带与下胫腓联合对踝关节稳定性的生物力学影响。方法采用6例新鲜踝关节标本,常规制成骨-韧带模型(标本可重复利用)。分为:A组:踝关节各韧带均完整;B组:三角韧带离断,下胫腓联合完整;C组:下胫腓联合离断,三角韧带完整;D组:下胫腓联合及三角韧带均离断;E组:锚钉修复三角韧带、螺钉固定下胫腓联合韧带组。对标本施加600 N轴向加载。分别测量三种体位(中立位、背伸10°位、跖屈20°位)在各种状态下胫距关节的接触面积、接触压力、压应力分布等变化。对比分析三角韧带及下胫腓联合韧带修复前后对踝关节稳定的作用。结果在三种体位下均可发现,随着下胫腓联合及三角韧带的离断,胫距关节接触面积逐渐减小,接触压力逐渐增大,与正常A组对比差异有统计学意义(P<0.05),压应力分布逐渐集中并有向外侧移位趋势;三角韧带与下胫腓联合修复前后的胫距关节的接触面积、接触压力等差异有统计学意义(P<0.05);修复后的胫距关节接触面积增大、接触压力减少,与正常组A组对比差异无统计学意义(P>0.05),压应力分布分散。结论三角韧带与下胫腓联合断裂后,距骨发生移位,胫距关节面接触面积、接触压力及压应力分布发生剧烈变化。目前骨锚钉修复三角韧带、螺钉固定下胫腓联合能获得即刻稳定,且其生物力学强度与正常组相似,推荐对三角韧带伴下胫腓联合损伤者行手术治疗以恢复其正常解剖关系。     

Ideal angle of syndesmotic screw fixation: A CT-based cross-sectional image analysis study

Without clear reference, the precision of syndesmotic screw placement cannot be guaranteed and malposition of these screws leads to poor results. Therefore, to prevent malpositioning of syndesmotic screws, an improved understanding of the orientation of tibiofibular syndesmosis is essential. We analyzed cross-sectional computed tomography (CT) scans of the foot and ankle to identify precise screw positions for the treatment of syndesmotic injuries. A total of 134 calcaneal fractures with intact tibiofibular syndesmosis were enrolled in this retrospective study. We measured the angle between the perpendicular line of the second proximal phalanx and the line start apex of the lateral cortex of the fibula bisecting the tibial incisura and crossing the center of the tibia in neutral ankle joints, with the second toe positioned anteriorly using a short leg splint. The second toe was used as the reference for clarity and applicability. The ideal angle of syndesmotic screw placement in cross-sectional CT images was 18.8 ± 5.6° (mean ± standard deviation) and did not differ according to independent variables (P > 0.05). In neutral ankle joints with the second toe positioned anteriorly, the ideal angle of syndesmotic screw placement is 18.8°, which is less than that currently in used in conventional methods.     

The role of the posterior malleolus in the treatment of unstable upper ankle joint injuries - A biomechanical study

BackgroundThis biomechanical study aimed to test if the fixation of the posterior malleolus (PM) only with screws inserted from posterior to anterior (PA) restores stability comparable with the natural condition. The extent of stability was also compared with that of anterior to posterior (AP) screw osteosynthesis (OS) with an additional syndesmotic screw (SS).MethodsFirst, the stability of the upper ankle joint in seven pairs of intact lower legs were examined. Subsequently, half of the lower legs were treated with PA screw fixation of a PM fracture without SS and the other half with AP screw fixation with additional tricortical SS.ResultsPA OS without SS showed significantly more diastasis (p = 0.027). The AP OS with an SS revealed a diastasis that was comparable with the intact condition (p = 0.797). The use of SS led to significantly higher stability compared to OS without SS (p = 0.019).ConclusionsThe Fixation of the PM alone without an additional syndesmotic screw cannot achieve intact upper ankle stability. Fixation of a PM fracture with an SS helps in nearly achieving the natural condition.     

Radiological assessment of ankle syndesmotic reduction

IntroductionThe intraoperative assessment of adequacy of syndesmotic reduction is challenging. The aim of this study was to develop a radiographic measure based on the lateral ankle view to assess both the normal and abnormal relationship between the tibia and fibula after simulated syndesmotic malreduction and to evaluate the effect on commonly used mortise measurements.MethodsMortise and talar dome lateral radiographs were obtained in eight fresh-frozen cadaveric specimens before and following syndesmosis division and posterior fibular displacement of 2 mm increments. Using the technique described, on the lateral radiograph the anterior fibular line ratio (AFL ratio) and posterior fibular line distance (PFL distance) were measured. Both measures were based on the anterior and posterior distal tibia articular margins and flat borders of the fibula.ResultsInter- and intraobserver reliability of the AFL ratio and PFL distance measured almost perfect agreement. In all uninjured specimens the AFL lay just anterior to the midpoint of the tibia and the PFL intersected the posterior tibia articular margin or lay just anterior to it, not posterior. At 2, 4 and 6 mm of posterior fibular displacement the decrease in AFL ratio and PFL distance showed significant differences between all pairwise comparisons.ConclusionThe proposed new measures of syndesmotic reduction are reproducible and capable of detecting from 2 mm of sagittal fibula displacement and can be useful adjuncts in the assessment of syndesmotic reduction.     

The effect of collateral ligament release on ankle dorsiflexion: An anatomical study

Background

Ankle stiffness is a common complication after ankle fracture, reconstructive surgery or total ankle replacement, and the usual limitation is in dorsiflexion. There are few articles in the literature concerning this frequent problem, and furthermore they are not recent and tend to be controversial. The purpose of this anatomical study was to evaluate and quantify the effect of ankle collateral ligament release on dorsiflexion, specifically the amount of increase in ankle dorsiflexion following section of the two ligaments most often implicated in ankle stiffness: the deep posterior tibiotalar ligament (dPTTaL, or posterior deep deltoid) and the posterior talofibular ligament (PTaFL).

Methods

We dissected 18 adult fresh cadaveric ankle joints, and with an electronic goniometer combined with an electronic dynamometer measured their mobility in dorsiflexion before and after transection of each ligament separately, and the two ligaments combined.

Results

The results showed a significant difference between the two groups of ankles with section of the dPTTaL resulting in a greater increase in ankle dorsiflexion than section of the PTaFL (mean 7.45° vs. 3.5°, respectively; p < 0.001). Combined section of both ligaments improved the gain in ankle dorsiflexion more than isolated section of each ligament, but was not statistically significant (p = 0.88).

Conclusion

If after gastrocnemius recession or Achilles tendon lengthening persistent restriction remains in ankle dorsiflexion, the results of our study demonstrate that the next step should be release of the dPTTaL.     

The isolated posterior malleolar fracture and syndesmotic instability: A case report and review of the literature

IntroductionAnkle fractures are among the most common type of fractures in the lower extremity. A posterior malleolar fracture is frequently part of a more complex ankle fracture and only in rare cases it occurs as isolated injury. Posterior malleolar fractures often occur with associated injuries, such as a Maisonneuve fracture or with bi- or trimalleolar ligamentous injuries. Knowledge about these associated injuries is essential to prevent missed diagnoses. The aim of this article is to describe the isolated posterior malleolar fracture, the possible associated injuries, the diagnostic work-up and therapeutic consequences.Presentation of caseWe present a case of a 26-year-old male patient who sustained an isolated posterior malleolar fracture with 4.5 years follow-up.DiscussionIsolated fractures of the posterior malleolus are uncommon injuries. Diagnosis, treatment and outcome can seldom be extracted from large series. However, several cases have been described in literature, which we have summarized.ConclusionThis case report and literature review shows that isolated posterior malleolar fractures might occur as part of a more complex ankle injury, in combination with a fracture of the lower leg or after high energy trauma. Physicians should be aware of these associated injuries. Diagnostic work-up should include X-rays of the knee and lower leg and a CT scan of the ankle. If diagnosed and treated properly, isolated posterior malleolar fractures have a good long-term functional outcome.     

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.     

Postoperative Computed Tomography–Based Control of Syndesmotic Screws

Abstract Purpose: Skeletal reconstruction and position of osteosynthetic devices, especially of the syndesmotic screws, were controlled postoperatively in order to check the accuracy of surgical intervention and of intraoperative C–arm control. Patients and Methods: This is a prospective, nonrandomized study of a closed series of 37 patients with ankle fractures AO type B and C who were treated according to the AO principles and in whom a syndesmotic screw was used. All patients underwent postoperative computed tomograpy. Results: Intraoperative radiography was judged to be normal by all surgeons. Retrospectively, it was considered to be abnormal in nine patients – verified by computed tomography in six –, normal in 22 patients, and technically imperfect in six. So, intraoperative radiography proved to be erroneous in nine patients (24.3%). Computed tomography revealed a less than perfect result in six of 37 patients (16.2%). In four patients this was due to pure anterior subluxation of the fibula. None of 13 patients who had a temporary Kirschner wire (K–wire) fixation of the fibula intraoperatively had a malposition, whereas six out of 24 patients (25%) without K–wire did show a malposition. A revision operation was carried out in five patients (13.5%). Conclusion: It can be stated, that the positioning of a syndesmotic screw is technically delicate, that intraoperative two–dimensional C–arm control is not sufficient to detect malpositions of the screw and/or the lateral malleolus, and that prior to screw placement temporary K–wire fixation of the fibula is mandatory. If plain radiography leaves any doubt about the quality of reduction, postoperative computed tomography is indicated.     

Screw fixation of the syndesmosis: a cadaver model comparing stainless steel and titanium screws and three and four cortical fixation

We assessed syndesmotic set screw strength and fixation capacity during cyclical testing in a cadaver model simulating protected weight bearing. Sixteen fresh frozen legs with artificial syndesmotic injuries and a syndesmotic set screw made of stainless steel or titanium, inserted through three or four cortices, were axially loaded with 800 N for 225,000 cycles in a materials testing machine. The 225,000 cycles equals the number of paces taken by a person walking in a below knee plaster during 9 weeks. Syndesmotic fixation failure was defined as: bone fracture, screw fatigue failure, screw pullout, and/or excessive syndesmotic widening. None of the 14 out of 16 successfully tested legs or screws failed. No difference was found in fixation of the syndesmosis when stainless steel screws were compared to titanium screws through three or four cortices. Mean lateral displacement found after testing was 1.05 mm (S.D. = 0.42). This increase in tibiofibular width exceeds values described in literature for the intact syndesmosis loaded with body weight. Based on this laboratory study it is concluded that the syndesmotic set screw cannot prevent excessive syndesmotic widening when loaded with a load comparable with body weight. Therefore, we advise that patients with a syndesmotic set screw in situ should not bear weight.     

To compare the efficacy between fixation with tightrope and screw in the treatment of syndesmotic injuries: A meta-analysis

Background

To compare the efficacy between fixation with suture-button and screw in the treatment of syndesmotic injuries: a meta-analysis.

Anterior-inferior tibiofibular ligament anatomical repair and augmentation versus trans-syndesmosis screw fixation for the syndesmotic instability in external-rotation type ankle fracture with posterior malleolus involvement: A prospective and comparative study

PurposeSyndesmosis injury is common in external-rotation type ankle fractures (ERAF). Trans-syndesmosis screw fixation, the gold-standard treatment, is currently controversial for its complications and biomechanical disadvantages. The purpose of this study was to introduce a new method of anatomically repairing the anterior-inferior tibiofibular ligament (AITFL) and augmentation with anchor rope system to treat the syndesmotic instability in ERAF with posterior malleolus involvement and to compare its clinical outcomes with that of trans-syndesmosis screw fixation.Methods53 ERAFs with posterior malleolus involvement received surgery, and the syndesmosis was still unstable after fracture fixation. They were randomised into screw fixation group and AITFL anatomical repair with augmentation group. Reduction quality, syndesmosis diastasis recurrence, pain (VAS score), time back to work, Olerud–Molander ankle score and range of motion (ROM) of ankle were investigated.ResultsOlerud–Molander score in AITFL repair group and screw group was 90.4 and 85.8 at 12-month follow-up (P > 0.05). Plantar flexion was 31.2° and 34.3° in repair and screw groups (P = 0.04). Mal-reduction happened in 5 cases (19.2%) in screw group while 2 cases (7.4%) in repair group. Postoperative syndesmosis re-diastasis occurred in 3 cases in screw group while zero in repair group (P > 0.05). Pain score was similar between the two groups (P > 0.05). Overall complication rate and back to work time were 26.9% and 3.7% (P = 0.04), 7.15 months and 5.26 months (P = 0.02) in screw group and repair group, respectively.ConclusionsFor syndesmotic instability in ERAF with posterior malleolus involvement, the method of AITFL anatomical repair and augmentation with anchor rope system had an equivalent functional outcome and reduction, earlier rehabilitation and less complication compared with screw fixation. It can be selected as an alternative.     

Relationship between fracture morphology of lateral malleolus and syndesmotic stability after supination-external rotation type ankle fractures

BackgroundSyndesmotic injury with supination-external rotation (SER)-type ankle fractures are well known for the serious damages to the osseous and soft tissue envelope. However, the Lauge-Hansen classification system does not provide sufficient information related to syndesmotic injury. In this study, we aimed to investigate factors for preoperative detection of syndesmotic injury according to fracture patterns in SER III and IV ankle fractures by using radiography and computed tomography (CT).MethodsAll operative SER III and IV ankle fractures treated by a single surgeon from 2009 to 2015 were enrolled in a retrospective database. Based on computed tomographic evidence and intra-operative Cotton test, stable and unstable groups of the ankle factures were divided.ResultsA total of 52 patients with SER III, 75 patients with SER IV, and 27 patients with SER IV equivalent ankle fractures were identified, with 106 in the unstable syndesmosis group (68.8%) and 48 patients in the stable syndesmosis group (31.2%). Medial space widening and fragment angle of the fibular posterior cortex were significant predictors. The cutoff values of these factors were 4.4 mm and 32.8 degrees, respectively.ConclusionsCT was superior to simple radiography in predicting syndesmotic injury at the preoperative period in SER-type III and IV. Medial space widening and fragment angle of the fibular posterior cortex, as predictive factors, showed significant correlations. In particular, sharper fragment angle of the posterior cortex indicated higher probability of instability that remained after fracture fixation.     

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

Syndesmotic rupture is present in 10 % of ankle fractures and must be recognized and treated to prevent late complications. The method of fixation is classically rigid fixation with one or two screws. Knowledge of the biomechanics of the syndesmosis has led to the development of new dynamic implants to restore physiologic motion during walking. One of these implants is the suture-button system. The purpose of this paper is to review the orthopaedic trauma literature, both biomechanical and clinical, to present the current state of knowledge on the suture-button fixation and to put emphasis on the advantages and disadvantages of this technique. Two investigators searched the databases of Pubmed/Medline, Cochrane Clinical Trial Register and Embase independently. The search interval was from January 1980 to March 2011. The search keys comprised terms to identify articles on biomechanical and clinical issues of flexible fixation of syndesmotic ruptures. Ninety-nine publications met the search criteria. After filtering using the exclusion criteria, 11 articles (five biomechanical and six clinical) were available for review. The biomechanical studies involved 90 cadaveric ankles. The suture-button demonstrated good resistance to axial and rotational loads (equivalent to screws) and resistance to failure. Physiologic motion of the syndesmosis was restored in all directions. The clinical studies (149 ankles) demonstrated good functional results using the AOFAS score, indicating faster rehabilitation with flexible fixation than with screws. There were few complications. Preliminary results from the current literature support the use of suture-button fixation for syndesmotic ruptures. This method seems secure and safe. As there is no strong evidence for its use, prospective randomized controlled trials to compare the suture-button to the screw fixation for ankle syndesmotic ruptures are required.