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.

     

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.

Use of tightrope fixation in ankle syndesmotic injuries

Objective： Conventional fixation of syndesmotic injuries with screws remains problematic. A novel fibrewire device （Tightrope） has suggested advantages. However, small case series have reported high soft tissue complication rates. The purpose of our study was to quantify complication rates and further procedures in patients treated with Tightropes. A secondary objective was to determine incidence of complications and further procedures in those treated with syndesmotic screws over the same period. Methods： All patients undergoing syndesmotic fixa- tion for ankle fracture between May 2008 and October 2009 were retrospectively reviewed. Incidence of complications, secondary procedures, maintenance of syndesmotic reduc- tion and time spent on non-weight bearing were recorded. Family doctors were contacted for those treated with Tight- ropes to check for any complications managed elsewhere. Results： Thirty-five patients required syndesmoticfixation, in which 12 were treated with Tightropes. They were followed up in clinic for a mean of 12.4 weeks. Family doctors were contacted at mean 14.6 months after treatment to determine any complications suffered. There were no complications attributable to method of fixation. In this series, 12 patients underwent 13 procedures and no patient had recurrent diastasis at discharge; 23 patients treated with screw fixation underwent 45 procedures （19 were screw removals）. There was 1 case ofsyndesmotic diastasis. Screw removal resulted in 2 minor complications. Conclusion： Tightrope fixation provideds effective syndesmotic fixation that is maintained at discharge. We do not experience soft tissue complications reported elsewhere.     

下胫腓联合损伤研究新进展

下胫腓联合一旦损伤分离会严重影响踝关节稳定性和功能,因此需对下胫腓联合的解剖结构、运动特征、损伤机制有充分的认识,对其诊断和治疗有深刻的理解.近几年许多国外学者一直围绕下胫腓联合的各个方面进行大量卓有成效的研究,解剖学研究中对临床相关的解剖数据进行精确测量;运动学研究中运用更为精细的仪器,相对清晰地测量描述出常规影像学检查无法观察或精确测量的运动模式;有学者回顾性研究下胫腓联合损伤机制的探讨文献,归纳出多种损伤机制;下胫腓联合损伤的诊断不仅保留和继承了传统临床试验及常规影像学检查,还不断提升和总结CT、MRI、踝关节镜及术中诊断技术的作用;治疗方面关注的焦点虽还集中于AO所推荐的下胫腓联合横行螺钉固定,但其技术细节正不断深化更新,新型固定技术、韧带修复重建理念也不断发展,特别是对下胫腓前韧带损伤的诊治更为重视.该文归纳总结了下胫腓联合损伤研究的最新进展和新观点.     

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.     

双带绊纽扣钢板和金属螺钉治疗下胫腓联合损伤的疗效比较

目的比较双带绊纽扣钢板和金属螺钉固定治疗下胫腓骨联合损伤的临床疗效。方法将45例踝部骨折伴下胫腓联合损伤患者按入院日期奇偶数分成两组:A组(25例)采用双带绊纽扣钢板固定治疗,B组(20例)采用金属螺钉固定治疗(10~12周取出金属螺钉)。术后6个月对两组踝关节AOFAS功能评分、踝关节活动度进行临床评估,测量胫骨远端后外侧缘与腓骨远端内侧缘之间的距离(TFCS)和胫骨前结节外侧缘与腓骨内侧缘之间水平距离(TFO),进行影像学评价。结果患者均获得随访,时间6~15个月。术后6个月两组的踝关节AOFAS功能评分、踝关节活动度、TFCS和TFO比较差异均无统计学意义(P0.05)。结论双带绊纽扣钢板治疗下胫腓联合损伤可达到与金属螺钉固定相同的效果,并且能保留生理性微动,有利于早期负重活动,降低了内固定物松动或断裂的发生率,更利于关节功能康复。     

Biomechanical comparison of the interosseous tibiofibular ligament and the anterior tibiofibular ligament

BACKGROUND: The mechanical importance of the interosseous tibiofibular ligament of the ankle is unclear. The purpose of the current study was to compare the stiffness and strength of the interosseous tibiofibular ligament to that of the anterior tibiofibular ligament. METHODS: Twelve pairs of ankles were obtained from the Maryland State Anatomy Board. All soft tissue was removed except for the interosseous tibiofibular ligament in one ankle of each pair and the anterior tibiofibular ligament in the contralateral ankle. The assignment of which ligament would be excised in the right or left ankle of each pair was random. The specimens were potted as bone-ligament-bone preparations and mounted in a servohydraulic testing machine so that the ligament's long axis was coincident with the actuator. Specimens were elongated at 0.5 mm/s until rupture. Failure load and failure site were recorded, and stiffness was calculated. Stiffness and failure loads were compared with a paired t-test. Significance was set at p < 0.05. RESULTS: The interosseous ligament was significantly stiffer (234 +/- 122 N/mm) than the anterior tibiofibular ligament (162 +/- 64 N/mm). The mean failure load of the interosseous tibiofibular ligament (822 +/- 298 N) was significantly greater than that of the anterior tibiofibular ligament (625 +/- 255 N). CONCLUSIONS: The interosseous tibiofibular ligament is stiffer and stronger than the anterior tibiofibular ligament. CLINICAL RELEVANCE. The current study suggests that the interosseous ligament plays an important role in the stability of the ankle, and its status should be part of the diagnostic evaluation in syndesmotic instability.     

下胫腓联合损伤诊治进展

下胫腓联合是由胫腓骨远端4条韧带组成的复合体,既维持着胫腓骨远端的稳定性,又使踝关节保持一定的微动特性.下胫腓联合损伤常伴发于踝关节骨折,治疗不当可能影响踝关节功能,出现踝关节不稳定、关节炎及慢性疼痛等并发症.目前下胫腓联合损伤确诊需通过临床体检、影像学检查,甚至关节镜检查进行综合判断.治疗上,下胫腓联合损伤后关节不稳...     

下胫腓联合损伤螺钉内固定治疗新进展

下胫腓联合对维持踝关节的稳定性、对重量的传导和行走都很重要。治疗不当易造成踝关节慢性不稳定、长期疼痛和创伤性关节炎。下胫腓联合损伤治疗方法较多,目前临床上应用最多的是用AO皮质骨螺钉行胫腓横向固定,但是对于如何运用螺钉横向固定下胫腓联合仍有争议。本文综述了下胫腓螺钉固定的技术现状,为临床应用提供实践指导。     

TightRope与金属螺钉内固定治疗下胫腓联合分离的临床疗效对比

目的探讨锁扣带袢钛板(Tight Rope)内固定与金属螺钉内固定2种术式治疗下胫腓联合分离的临床疗效。方法笔者自2012-01—2016-03采用Tight Rope(Tight Rope组)与金属螺钉(金属螺钉组)2种内固定术式治疗46例下胫腓联合分离伴或不伴踝关节骨折。分别记录2组术前、术后即刻、术后3个月、末次随访时后前位X线片上下胫腓间隙(TBCS)、下胫腓重叠距离(TBOL),观察比较2组术后VAS评分、部分负重时间、完全负重时间、AOFAS踝与后足功能评分。结果 2组手术均顺利完成,术后切口均一期愈合,均获得平均14(11~18)个月随访。2组术前、术后即刻、术后3个月、末次随访时TBCS、TBOL差异无统计学意义(P0.05);2组术后3 d VAS评分差异无统计学意义(P0.05);Tight Rope组术后部分负重时间及完全负重时间均少于金属螺钉组,差异有统计学意义(P0.05);Tight Rope组术后3个月及6个月的AOFAS踝与后足评分高于金属螺钉组,差异有统计学意义(P0.05),2组末次随访时AOFAS踝与后足功能评分差异无统计学意义(P0.05)。金属螺钉组出现1例螺钉弯曲、1例螺钉断裂,Tight Rope组无内固定松动、断裂等并发症。2组均无下胫腓联合再次分离、踝关节再次骨折等并发症。结论 Tight Rope内固定与螺钉内固定均为治疗下胫腓联合分离的可靠性方法;Tight Rope组可早期功能锻炼及下地负重,踝关节功能恢复较金属螺钉组更有优势。     

Biomechanical analysis of endobutton versus screw fixation after Lisfranc ligament complex sectioning

BackgroundOur goal was to compare diastasis after endobutton and screw fixation after Lisfranc ligament complex sectioning.MethodsTwenty-four (12 pairs) fresh-frozen cadaveric feet were assigned to endobutton or screw fixation and loaded to 343 N. Displacement (first–second metatarsal bases) was measured in intact feet and after ligament sectioning (Lisfranc, medial–intermediate cuneiform ligaments), fixation, and 10,000 cycles.ResultsThe mean change in diastasis for endobutton and screw fixation under initial loading was 1.0 mm (95% CI, 0.2–1.9 mm) and 0.0 mm (95% CI, ?0.4 to 0.4 mm), respectively (p = 0.017). After cyclic loading, diastasis decreased (mean, ?0.7 mm, 95% CI, ?1.2 to ?0.1 mm) in the endobutton group but was unchanged in the screw group (p = 0.035).ConclusionsDiastasis after endobutton fixation was significantly greater than after screw fixation under initial loading but did not increase further after cyclic loading.     

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.     

Acute distal tibiofibular syndesmosis injury: a systematic review of suture-button versus syndesmotic screw repair

Purpose

Recently, a new suture-button fixation device has emerged for the treatment of acute distal tibiofibular syndesmotic injuries and its use is rapidly increasing. The current systematic review was undertaken to compare the biomechanical properties, functional outcome, need for implant removal, and the complication rate of syndesmotic disruptions treated with a suture-button device with the current ''gold standard'', i.e. the syndesmotic screw.

Method

A literature search in the electronic databases of the Cochrane Library, EMbase, Pubmed Medline, and Google Scholar, between January 1st 2000 to December 1st 2011, was conducted to identify studies in which unstable ankle fractures with concomitant distal tibiofibular syndesmotic injury were treated with either a syndesmotic screw or a suture-button device.

Results

A total of six biomechanical studies, seven clinical full-text studies and four abstracts on the TightRope system, and 27 studies on syndesmotic screw or bolt fixation were identified. The AOFAS of 133 patients treated with TightRope was 89.1 points, with an average study follow-up of 19 months. The AOFAS score in studies with 253 patients treated with syndesmotic screws (metallic and absorbable) or bolts was 86.3 points, with an average study follow-up of 42 months. Two studies reported an earlier return to work in the TightRope group. Implant removal was reported in 22 (10%) of 220 patients treated with a TightRope (range, 0–25%), in the screw or bolt group the average was 51.9% of 866 patients (range, 5.8–100%).

Conclusion

The TightRope system has a similar outcome compared with the syndesmotic screw or bolt fixation, but might lead to a quicker return to work. The rate of implant removal is lower than in the syndesmotic screw group. There is currently insufficient evidence on the long-term effects of the TightRope and more uniform outcome reporting is desirable. In addition, there is a need for studies on cost-effectiveness of the treatment of acute distal tibiofibular syndesmotic disruption treated with a suture-button device.     

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.     

Surgical treatment of syndesmotic diastasis: emphasis on effect of syndesmotic screw on ankle function

Fifty-two consecutive adult patients with syndesmotic diastasis (SD) were treated with closed anatomical reduction and stable fixation by a trans-syndesmotic cancellous screw. A short leg splint was prescribed for a six week postoperative period. Treatment outcomes of syndesmotic screw removal at various time points were studied and compared (group 1 at six weeks, group 2 at three months and group 3 at an average of nine months). Recurrence of SD, incidence of syndesmotic screw breakage and ankle function were compared among the three groups. Recurrence of SD occurred in 15.8% (3/19) of patients in group 1, 15.0% (3/20) in group 2 and 0% (0/13) in group 3 (p = 0.054). Breakage of the syndesmotic screw occurred in three patients within three months (group 2, 15.0%) and in two patients beyond three months (group 3, each at six and 12 months, 15.4%). None of the group 1 patients experienced screw breakage (p = 0.034). Forty-three patients (82.7%) were classified as having satisfactory outcomes. Ankle function did not significantly differ among the three groups (p = 0.191), with or without syndesmotic screw breakage (p = 0.343) and with or without SD recurrence (p = 0.218). In conclusion, restriction of daily activity for at least three months is required to prevent recurrence. Removal of the syndesmotic screw at six weeks may prevent its breakage but increases the risk of recurrence. Over an average follow-up of 19 months, SD recurrence does not lead to deterioration in ankle function.     

Biomechanical comparison of occipitoatlantal screw fixation techniques

OBJECT: The stability provided by 3 occipitoatlantal fixation techniques (occiput [Oc]-C1 transarticular screws, occipital keel screws rigidly interconnected with C-1 lateral mass screws, and suboccipital/sublaminar wired contoured rod) were compared. METHODS: Seven human cadaveric specimens received transarticular screws and 7 received occipital keel-C1 lateral mass screws. All specimens later underwent contoured rod fixation. All conditions were studied with and without placement of a structural graft wired between the skull base and C-1 lamina. Specimens were loaded quasistatically using pure moments to induce flexion, extension, lateral bending, and axial rotation while recording segmental motion optoelectronically. Flexibility was measured immediately postoperatively and after 10,000 cycles of fatigue. RESULTS: Application of Oc-C1 transarticular screws, with a wired graft, reduced the mean range of motion (ROM) to 3% of normal. Occipital keel-C1 lateral mass screws (also with graft) offered less stability than transarticular screws during extension and lateral bending (p < 0.02), reducing ROM to 17% of normal. The wired contoured rod reduced motion to 31% of normal, providing significantly less stability than either screw fixation technique. Fatigue increased motion in constructs fitted with transarticular screws, keel screws/lateral mass screw constructs, and contoured wired rods, by means of 19, 5, and 26%, respectively. In all constructs, adding a structural graft significantly improved stability, but the extent depended on the loading direction. CONCLUSIONS: Assuming the presence of mild C1-2 instability, Oc-C1 transarticular screws and occipital keel-C1 lateral mass screws are approximately equivalent in performance for occipitoatlantal stabilization in promoting fusion. A posteriorly wired contoured rod is less likely to provide a good fusion environment because of less stabilizing potential and a greater likelihood of loosening with fatigue.