Ankle joint contact loads and displacement in syndesmosis injuries repaired with Tightropes compared to screw fixation in a static model

BackgroundThe effect of syndesmotic fixation on restoration of pressure mechanics in the setting of a syndesmotic injury is largely unknown. The purpose of this study is to examine the contact mechanics of the tibiotalar joint following syndesmosis fixation with screws versus a flexible fixation device for complete syndesmotic injury.MethodsSix matched pairs of cadaveric below knee specimens were dissected and motion capture trackers were fixed to the tibia, fibula, and talus and a pressure sensor was placed in the tibiotalar joint. Each specimen was first tested intact with axial compressive load followed by external rotation while maintaining axial compression. Next, syndesmotic ligaments were sectioned and randomly assigned to repair with either two TightRopes® or two 3.5 mm cortical screws and the protocol was repeated. Mean contact pressure, peak pressure, reduction in contact area, translation of the center of pressure, and relative talar and fibular motion were calculated. Specimens were then cyclically loaded in external rotation and surviving specimens were loaded in external rotation to failure.ResultsNo differences in pressure measurements were observed between the intact and instrumented states during axial load. Mean contact presure relative to intact testing was increased in the screw group at 5 Nm and 7.5 Nm torque. Likewise, peak pressure was increased in the TightRope group at 7.5 Nm torque. There was no change in center of pressure in the TightRope group at any threshold; however, at every threshold tested there was significant medial and anterior translation in the screw group relative to the intact state.ConclusionEither screws or TightRope fixation is adequate with AL alone. With lower amounts of torque, the TightRope group appears to have contact and pressure mechanics that more closely match native mechanics.     

Comparison of the syndesmotic staple to the transsyndesmotic screw: a biomechanical study

BACKGROUND: Controversy still exists about treatment of syndesmotic injuries. This study compared the fixation strengths and biomechanical characteristics of two types of ankle fracture syndesmotic fixation devices: the barbed, round staple and the 4.5-mm cortical screw. METHODS: Cadaveric testing was done on 21 fresh-frozen knee disarticulation specimens in biaxial servohydraulic Instron testing equipment. Submaximal torsional loads were applied to specimens in intact and Weber C bimalleolar fracture states. The specimens were then fixed with one of two techniques and again subjected to submaximal torsion and torsion to failure. Biomechanical parameters measured included tibiofibular translation and rotation, maximal torque to failure, and degrees of rotation at failure. RESULTS: Compared to the intact state before testing, the staple held the fibula in a more anatomic position than the screw for mediolateral and anterior displacements (p < 0.01). With submaximal torsional testing, the staple restored 85% of the tibiofibular external rotation and all of the posterior translation values as compared to the intact state. The screw resulted in 203% more tibiofibular medial translation and 115% more external rotation than the intact state. The degree of tibial rotation during submaximal torsional loading was restored to within 15% of intact values but was 21% less with the screw. There was no statistical difference between the screw and staple when tested in load to failure. Tibiotalar rotation at failure was statistically different with the staple construct, allowing more rotation as compared to the screw. CONCLUSION: The staple restored a more physiologic position of the fibula compared to the syndesmotic screw. Both provided similar performance for the load to failure testing, while the screw reduced tibial rotation more after cyclic loading. There was more tibial rotation before failure for the staple, suggesting a more elastic construct. This study provides biomechanical data to support the clinical use of the syndesmotic staple.     

Novel Flexible Suture Fixation for the Distal Tibiofibular Syndesmotic Joint Injury: A Cadaveric Biomechanical Model

Syndesmotic injuries of the ankle commonly occur by an external rotation force applied to the ankle joint. Ten fresh-frozen lower extremities from cadavers were used. A specially designed apparatus was used to stabilize the specimen and rotate the ankle joint from internally rotated 25° to externally rotated 35° at a rate of 6°/s for 10 cycles. Two stages were tested (stage I, specimens intact; and stage II, simulated pronation external rotation type injury with fixation). Group 1 was fixed with a novel suture construct across the syndesmotic joint, and group 2 was fixed with a single metallic screw. The torque, rotational angle, and 3-dimensional syndesmotic diastasis readings were recorded. Three-dimensional tibiofibular diastasis was identified. The fibula of the intact specimens displaced an average of 8.6 ± 1.7, 2.4 ± 1.0, and 1.4 ± 1.0 mm in the anterior, lateral, and superior direction, respectively, when the foot was externally rotated 35°. The sectioning of the syndesmostic ligaments and deltoid ligament resulted in a significant decrease in syndesmotic diastasis and foot torsional force (p < .05). The ligament-sectioned specimen lost 57% (externally rotated) and 17% (internally rotated) torsional strength compared with the intact specimen. Groups 1 and 2 provided similar biomechanical stability in this cadaveric model of a syndesmosis deficiency.     

Biomechanical comparison of syndesmosis fixation with 3.5- and 4.5-millimeter stainless steel screws

Although most authors recommend either 3.5-mm or 4.5-mm cortical screws for syndesmosis fixation, the optimum screw size has yet to be defined. The present study was designed to biomechanically compare syndesmosis fixation with 3.5-mm and 4.5-mm stainless steel screws. Simulated pronation external rotation ankle injuries were created in twelve paired, fresh-frozen cadaveric leg specimens. One limb from each pair received a 3.5-mm tricortical stainless steel screw for syndesmosis fixation (group I), while the contralateral specimen was stabilized using a 4.5-mm screw (group II). Sub-maximal axial ramp (0 to 1200 N) and external rotation/torsional ramp (0 to 5 N-m) loading was performed on each specimen prior to ligament division, following ligament division and following syndesmosis fixation. Axial fatigue testing was then performed at 1.5 Hz for a total of 100,000 cycles (0 to 900 N), and each specimen was subsequently tested to failure in external rotation. Ligament division resulted in syndesmosis widening (p<0.001) and reduced stiffness (p<0.001) during torsional ramp loading. Subsequent syndesmosis screw placement reduced syndesmosis widening (p<0.05) and increased stiffness (p<0.05). Following screw fixation, however, widening remained greater (p<0.005) and stiffness less (p<0.001) than pre-injury levels. No differences between groups I and II were observed during submaximal testing. In external rotation to failure testing, group I failed at a greater angle (38.9 degrees +/- 4.1 degrees vs. 32.0 degrees +/- 3.8 degrees in group II; p<0.05). Failure torque was slightly higher in group I; however, the difference was not statistically significant (17.8 +/- 2.0 N-m vs. 14.3 +/- 2.6 N-m in group II; p=0.082). Five specimens in group I failed by screw pullout and five specimens in group II failed by fibula fracture (p=0.061). The present results suggest that there is no biomechanical advantage of a 4.5-mm screw over a 3.5-mm in fixation of the syndesmosis.     

Comparison of a novel FiberWire-button construct versus metallic screw fixation in a syndesmotic injury model

BACKGROUND: There is minimal experience with less rigid syndesmotic fixation devices which may approximate the normal distal tibio-fibular mechanics during healing. This study evaluates the ability of a FiberWire-button implant (Arthrex, Naples, FL) to maintain syndesmotic reduction as compared with a metallic screw. METHODS: Ten matched fresh-frozen cadaveric ankle pairs with intact ligaments were tested (12.5 Nm external rotation force) to establish physiologic syndesmotic diastasis. The same force was applied to the ankles after sectioning of the syndesmotic and deltoid ligaments. Within the pairs, each limb was randomized to receive a FiberWire-button implant or a metallic screw (Synthes, Paoli, PA); the ankles were tested for syndesmotic diastasis with progressive external rotation force, from 2.5 Nm to 25 Nm (or failure). RESULTS: There was no significant difference in diastasis amongst pairs with intact or sectioned syndesmosis (p=0.64 and p=0.80, respectively). There was a significantly greater diastasis in the FiberWire-button group at all external rotation loads (p<0.0001). Nine of the ten pairs failed (all through fracture of the distal fibula). There were no hardware failures. The metallic screw group failed at a lower load (mean 15 Nm) compared to the FiberWire-button group (mean 18 Nm, p=0.0004). The metallic screw group maintained syndesmotic reduction up to 5 Nm of force. CONCLUSIONS: The FiberWire-button was unable to maintain syndesmotic reduction of the ankles at any of the forces applied. The ankles fixed with the FiberWire-button demonstrated significantly greater widening of the syndesmosis compared to the screw, at all loads. CLINICAL RELEVANCE: The FiberWire-button implant may not maintain adequate ankle syndesmotic reduction in the immediate post-operative period relative to a metallic screw.     

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.     

Comparing Different Surgical Techniques for Addressing the Posterior Malleolus in Supination External Rotation Ankle Fractures and the Need for Syndesmotic Screw Fixation

Trimalleolar ankle fractures are unstable injuries with possible syndesmotic disruption. Recent data have described inherent morbidity associated with screw fixation of the syndesmosis, including the potential for malreduction, hardware irritation, and post-traumatic arthritis. The posterior malleolus is an important soft tissue attachment for the posterior inferior syndesmosis ligament. We hypothesized that fixation of a sizable posterior malleolar (PM) fracture in supination external rotation type IV (SER IV) ankle fractures would act to stabilize the syndesmosis and minimize or eliminate the need for trans-syndesmotic fixation. A retrospective review of trimalleolar ankle fractures surgically treated from October 2006 to April of 2011 was performed. A total of 143 trimalleolar ankle fractures were identified, and 97 were classified as SER IV. Of the 97 patients, 74 (76.3%) had a sizable PM fragment. Syndesmotic fixation was required in 7 of 34 (20%) and 27 of 40 (68%), respectively, when the PM was fixed versus not fixed (p = .0002). When the PM was indirectly reduced using an anterior to posterior screw, 7 of 15 patients (46.7%) required syndesmotic fixation compared with none of 19 patients when the PM fragment was fixated with direct posterior lateral plate fixation (p = .0012). Fixation of the PM fracture in SER IV ankle fractures can restore syndesmotic stability and, thus, lower the rate of syndesmotic fixation. We found that fixation of a sizable PM fragment in SER IV or equivalent injuries through posterolateral plating can eliminate the need for syndesmotic screw fixation.     

Mid-diaphyseal fibular fractures with syndesmotic disruption: should we plate the fibula?

BACKGROUND: The treatment of mid-diaphyseal fibula fractures with syndesmotic disruption is controversial. The purpose of this study was to compare the biomechanical properties of 2 fixation constructs. MATERIALS AND METHODS: Eight pairs of human cadaveric legs were divided into two groups, both of which had midshaft fibular osteotomies and disruption of all ligamentous support up to the osteotomy level. In Group I, the left legs were fixed with only a 3.5-mm tricortical syndesmotic screw. In Group II, the right legs received this syndesmotic fixation in addition to plating of the fibula. Rotational stability was tested on each ankle in the intact, repaired, and post-cyclical load conditions. Each specimen was ultimately tested to failure in external rotation. RESULTS: The rotational stability, load to failure, and stiffness were all found to be significantly higher with the plate and syndesmotic fixation repair technique (Group II) than with the syndesmotic fixation only technique (Group I). Furthermore, fixation in Group II improved rotational stability both before and after cyclic loading. CONCLUSION: Improved biomechanical properties were found with fibular plating in addition to a syndesmotic screw in a midshaft fibular fracture model with syndesmotic and deltoid injury. CLINICAL RELEVANCE: This information may be helpful in the decision-making process to optimally treat patients with this fracture pattern.     

The Role of Deltoid Ligament Repair in Ankle Fractures With Syndesmotic Instability: A Systematic Review

Ankle fractures are the fourth most common fracture requiring surgical management. The deltoid ligament is a primary ankle stabilizer against valgus forces. It is frequently ruptured in ankle fractures; however, there is currently no consensus regarding repair. A systematic database search was conducted with Medline, PubMed, and Embase for relevant studies discussing patients with ankle fractures involving deltoid ligament rupture and repair. Screening, quality assessment, and data extraction were performed independently and in duplicate. Data extracted included pain, range of motion (ROM), function, medial clear space (MCS), syndesmotic malreduction, and complications. After screening, 9 eligible studies from 1990 to 2018 were included (N = 508). Compared to nonrepair groups, deltoid ligament repair patients had lower syndesmotic malreduction rates (0%-9% vs 20%-35%, p ≤ .05), fewer implant removals (5.8% vs 41% p ≤ .05), and longer operating time by 16-20 minutes (p ≤ .05). There was no significant difference for pain, function, ROM, MCS, and complication rate (p ≤ .05). In conclusion, deltoid ligament repair offers lower syndesmotic malreduction rates and reduced re-operation rates for hardware removal in comparison to trans-syndesmotic screws. Repair groups demonstrated equivalent or better outcomes for pain, function, ROM, MCS, and complication rates. Other newer syndesmotic fixation methods such as suture-button fixation require further evaluation when compared to the outcomes of deltoid ligament repair. A randomized control trial is required to further examine the outcomes of ankle fracture patients who undergo deltoid ligament repair versus trans-syndesmotic screw fixation.     

Screw versus suture button in treatment of syndesmosis instability: Comparison using weightbearing CT scan

BackgroundThe superiority of screw or suture button fixation for syndesmotic instability remains debatable. Our aim is to compare radiographic outcomes of screw and suture button fixation of syndesmotic instability using weight bearing CT scan (WBCT).MethodsTwenty patients with fixation of unilateral syndesmotic instability were recruited and divided among two groups (screw = 10, suture button = 10). All patients had WBCT of both ankles ≥12 months postoperatively.ResultsIn suture button group, injured side measurements were significantly different from normal side for syndesmotic area (P = 0.003), fibular rotation (P = 0.004), anterior difference (P = 0.025) and direct anterior difference (P = 0.035). In screw group, syndesmotic area was the only significantly different measurement (P = 0.006).ConclusionWhile both screw and suture button didn’t completely restore the syndesmotic area as compared to the contralateral uninjured ankle, external malrotation of the fibula was uniquely associated with suture button fixation.Level of EvidenceIII Retrospective Cohort Study     

Biomechanical comparison of screw,tightrope and novel double endobutton in the treatment of tibiofibular syndesmotic injuries

BackgroundAdequate reduction and stabilization of the syndesmosis are significant to prevent early degeneration of the ankle joint and get better clinical outcomes. However, the routine surgical methods have diffierent limitations. The purpose of this study was to develop a novel double Endobutton fixation to treat the distal tibiofibular syndesmotic injuries, and determine whether the novel double Endobutton fixation demonstrates a better biomechanical property compare with the intact syndesmosis, the screw fixation and the Tightrope fixation.MethodsTwenty-four normal fresh-frozen ankle specimens with a mean age of 42 ± 8 (range, 28–62) years were randomly divided equally into four groups: (1) the intact group, (2) the screw group, (3) the Tightrope group, (4) the Endobutton group. 3D printer technology was used to establish the personalized distal tibiofibular syndesmotic navigation modules to determine the accurate bone tunnel. Axial loading was applied in five ankle positions: neutral position, dorsiflexion, plantar flexion, varus and valgus. Rotation torque was applied in two ankle rotation of the neutral position: internal and external.ResultsIn most situations, the displacements of the intact group were larger than the screw group, the Tightrope group and the Endobutton group (P < .05), and the displacements of the screw group were smaller than other three groups (P < .05). The displacements of the double Endobutton group were slightly larger than the Tightrope group but no significant differences were found between these two groups except in the dorsiflexion position of axial loading experiments (P < .05). The novel double Endobutton fixation was steadier than intact syndesmosis and more micromotional than screw fixation.ConclusionOur study demonstrated that the novel double Endobutton can be considered as the better fixation in treatment of distal tibiofibular syndesmotic injuries.Level of EvidenceLevel III, retrospective comparative study     

Syndesmotic Internal Brace~(TM) for anatomic distal tibiofibular ligament augmentation

Reconstruction of unstable syndesmotic injuries is not trivial, and there is no generally accepted treatment guidelines. Thus, there still remain considerable controversies regarding diagnosis, classification and treatment of syndesmotic injuries. Syndesmotic malreduction is the most common indication for early re-operation after ankle fracture surgery, and widening of the ankle mortise by only 1 mm decreases the contact area of the tibiotalar joint by 42%. Outcome of ankle fractures with syndesmosis injury is worse than without, even after surgical syndesmotic stabilization. This may be due to a high incidence of syndesmotic malreduction revealed by increasing postoperative computed tomography controls. Therefore, even open visualization of the syndesmosis during the reduction maneuver has been recommended. Thus, the most important clinical predictor of outcome is consistently reported as accuracy of anatomic reduction of the injured syndesmosis. In this context the Tight Rope~?system is reported to have advantages compared to classical syndesmotic screws. However, rotational instability of the distal fibula cannot be safely limited by use of 1 or even 2 Tight Ropes~?. Therefore, we developed a new syndesmotic Internal Brace~(TM) technique for improved anatomic distal tibiofibular ligament augmentation to protect healing of the injured native ligaments. The Internal Brace~(TM) technique was developed by Gordon Mackay from Scotland in 2012 using Swive Locks~? for knotless aperture fixation of a Fiber Tape~? at the anatomic footprints of the augmented ligaments, and augmentation of the anterior talofibular ligament, the deltoid ligament, the spring ligament and the medial collateral ligaments of the knee have been published so far. According to the individual injury pattern,patients can either be treated by the new syndesmotic Internal Brace~(TM) technique alone as a single anterior stabilization, or in combination with one posteriorly directed Tight Rope~? as a double stabilization, or in combination with one Tight Rope~? and a posterolateral malleolar screw fixation as a triple stabilization. Moreover,the syndesmotic Internal Brace~(TM) technique is suitable for anatomic refixation of displaced bony avulsion fragments too small for screw fixation and for indirect reduction of small posterolateral tibial avulsion fragments by anatomic reduction of the anterior syndesmosis with an Internal Brace~(TM) after osteosynthesis of the distal fibula. In this paper, comprehensively illustrated clinical examples show that anatomic reconstruction with rotational stabilization of the syndesmosis can be realized by use of our new syndesmotic Internal Brace~(TM) technique. A clinical trial for evaluation of the functional outcomes has been started at our hospital.     

Which Ankle Fractures Require Syndesmotic Stabilization?

Syndesmotic ruptures associated with ankle fractures are most commonly caused by external rotation of the foot, eversion of the talus within the ankle mortise, and excessive dorsiflexion. The distal tibiofibular syndesmosis consists of the anterior inferior tibiofibular ligament, posterior inferior tibiofibular ligament, and interosseous ligament, and it is essential for stability of the ankle mortise. Despite the numerous biomechanical and clinical studies pertaining to ankle fractures, there are no uniform recommendations regarding the use of the syndesmotic screw for specific injury patterns and fracture types. The objective of this review was to formulate recommendations for clinical practice related to the use of syndesmotic screw placement.     

Early radiographic outcomes following deltoid ligament repair in bimalleolar equivalent ankle fractures

BackgroundIndications for deltoid ligament repair in bimalleolar equivalent ankle fractures are unclear. This study compared radiographic outcomes in bimalleolar equivalent ankle fractures undergoing open reduction internal fixation (ORIF) +/? deltoid ligament repair.MethodsA retrospective review of 1024 ankle fractures was performed. Bimalleolar equivalent injuries treated with ORIF +/? deltoid ligament repair were included. Radiographic assessment was performed preoperatively, and at three months postoperatively.ResultsOne hundred and forty-seven ankle fractures met inclusion criteria with 46 undergoing deltoid ligament repairs. There was a significant decrease in medial clear space (1.93 ± 0.65 mm vs. 2.26 ± 0.64 mm, p = 0.01), and tibiofibular clear space (3.89 ± 1.20 mm vs. 4.87 ± 1.37 mm, p = 0.0001) at 3 months postoperative in the deltoid repair group compared to the no repair group. When syndesmotic fixation was performed, there were no differences between groups.ConclusionDeltoid ligament repair in bimalleolar equivalent ankle fractures resulted in reduced medial clear space, and tibiofibular clear space in the early postoperative period. These differences were small and remained within established normal limits.Level of clinical evidenceLevel III, retrospective cohort study.     

Ankle mortise stability in Weber C fractures: indications for syndesmotic fixation

A Weber type C ankle fracture was sequentially reproduced in 12 cadaver lower extremities and an external rotation torque was applied at each interval. The fractures were then repaired in staged fashion and the rotational stability of the mortise evaluated. Maximum external rotation of the talus within the mortise averaged 7.7 degrees in the intact ankle and increased by 311% to 31.8 degrees after creation of a Weber C injury. Rigid fixation of the fibular fracture restored 32% of the rotational stability, whereas isolated fixation of the medial malleolus reconstituted 57%. Fibular fixation combined with a syndesmotic screw restored 51% of original stability, and the addition of medial malleolar fixation improved stability to 101%. Bimalleolar fixation without a syndesmotic screw yielded 73% of the original rotational stability. The results of this study suggest that when rigid medial and lateral osteosynthesis can be achieved, syndesmotic fixation may not be necessary.     

Stability at the half pin–frame interface on external fixation constructs

A mechanical study investigating the use of two different methods (grub and bolt screws) to secure external fixation half pins to circular frames. A four part experiment: (1) Grub and bolt screws were used to secure half pins in Taylor Spatial frames. Loosening torques were measured using a calibrated torque wrench. (2) Using universal testing machine (UTM), axial loading was applied to establish thresholds for loosening in grub and bolt screw constructs. (3) We established the application torque to produce failure at the head–driver interface using these two methods. (4) Grub and bolt screw constructs were created controlling torque. Using UTM, axial loading was applied to establish thresholds for loosening. Statistical analysis was conducted using SPSS v20.0.0. (1) Higher torque is employed when bolt rather than grub screws is used to secure half pins on Rancho cubes (p < 0.05). (2) Loading threshold for loosening is higher in bolt screw constructs when the torque applied to secure the constructs is not controlled (p < 0.05). (3) Torque required for failure at the head–driver interface was 5.3 Nm for grub screws and 9.9 Nm for bolts. (4) Loading threshold for loosening is higher in grub screw constructs when the same torque was applied to secure them (p < 0.05). Bolt screws can be employed to secure the half pin–frame interface. They offer good stability and reduce failure at the head–driver interface. Further research is needed to determine the mechanical properties of such constructs in vivo.     

The multi-ligament ankle fracture: Epidemiology,key anatomical findings and fixation strategies in unstable open injuries

BackgroundAnkle fracture surgery has traditionally focussed on restoration of bony anatomy, with fixation of the malleoli and syndesmotic stabilisation where applicable. However, high energy open fracture-dislocations can also result in periosteal stripping of the stabilising capsuloligamentous attachments. As such, restoration of osseous anatomy alone may not result in sufficient articular stability.ObjectivesIn this series from a level 1 trauma centre, we report a subset of highly unstable open ankle fractures with combined capsuloligamentous injuries, in which restoration of osseous anatomy did not result in a stable joint. Supplementary soft tissue reconstruction and other stabilisation techniques were required.MethodsRetrospective case series of eligible patients from a level 1 trauma centre. Inclusion criteria were open ankle fractures with tibial extrusion (AO 44) and persistent instability post-bony fixation, age over 18 years and non-diabetic. Analysis of injury pattern, mechanism, pathological anatomy, soft tissue and orthopaedic reconstruction methods was performed.Results16 patients were identified during the study period who met the eligibility criteria, out of 95 open ankle fractures treated between January 2017–December 2020. Most patients were under 65 (n = 13; 81.3%) and sustained combined or isolated injuries of the deltoid ligament, anterior capsule, lateral ligament complex (ATFL±CFL) and tibialis posterior retinaculum. The commonest injury pattern was tibial extrusion via a medial soft tissue defect with deltoid ligament and anteromedial capsule rupture. Associated syndesmotic instability and fixation was common (n = 10; 62.5%). Supplementary stabilisation methods to standard bony fixation included capsuloligamentous reconstruction or repair, “ORIF+” external fixation, or conversion to primary fusion or hindfoot nail. Six patients required either local or free flap soft tissue coverage.ConclusionsA subset of up to 20% of open ankle fractures require supplementary fixation beyond anatomical restoration of the bony anatomy due to persistent ligamentous instability. They are associated with capsuloligamentous and syndesmotic disruption, more commonly affecting the medial structures. These rare injuries can be defined as multi-ligament ankle fractures. Surgeons should be aware of this subset and be able to recognise where supplementary stabilisation strategies are required.     

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.     

Evaluation of Transsyndesmotic Fixation and Primary Deltoid Ligament Repair in Ankle Fractures With Suspected Combined Deltoid Ligament Injury

The present prospective study examined the utility of the intraoperative tap test/technique for distal tibiofibular syndesmosis in the diagnosis of deltoid ligament rupture and compared the outcomes of transsyndesmotic fixation to deltoid ligament repair with suture anchor. This diagnostic technique was performed in 59 ankle fractures with suspected deltoid ligament injury. The width of the medial clear space of 59 cases was evaluated to assess the sensitivity and specificity. Those with deltoid ligament rupture were randomly assigned to 2 groups and treated with deltoid ligament repair with a suture anchor or with syndesmosis screw fixation. All the patients were assessed with the American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot scale, short-form 36-item questionnaire (SF-36), and visual analog scale (VAS). The tap test was positive in 53 cases. However, surgical exploration demonstrated that 51 cases (86.4%) had a combined deltoid ligament injury and fracture. The sensitivity and specificity of the tap test was 100.0% and 75.0%, respectively. Finally, 26 cases (96.3%) in the syndesmosis screw group and 22 (91.7%) in the deltoid repair group were followed up. No statistically significant differences were found in the AOFAS ankle-hindfoot scale score, SF-36 score, or VAS score between the 2 groups. The malreduction rate in the syndesmosis screw group was 34.6% and that in the deltoid repair group was 9.09%. The tap test is an intraoperative diagnostic method to use to evaluate for deltoid ligament injury. Deltoid ligament repair with a suture anchor had good functional and radiologic outcomes comparable to those with syndesmotic screw fixation but has a lower malreduction rate. We did not encounter the issue of internal fixation failure or implant removal.     

Overtightening of the syndesmosis revisited and the effect of syndesmotic malreduction on ankle dorsiflexion

BackgroundAnkle syndesmotic injuries are a significant source of morbidity and require anatomic reduction to optimize outcomes. Although a previous study concluded that maximal dorsiflexion during syndesmotic fixation was not required, methodologic weaknesses existed and several studies have demonstrated improved ankle dorsiflexion after removal of syndesmotic screws.The purposes of the current investigation are: (1) To assess the effect of compressive syndesmotic screw fixation on ankle dorsiflexion utilizing a controlled load and instrumentation allowing for precise measurement of motion. (2) To assess the effect of anterior & posterior syndesmotic malreduction after compressive syndesmotic screw fixation on ankle dorsiflexion.Material and methodsFifteen lower limb cadaveric leg specimens were utilized for the study. Ankle dorsiflexion was measured utilizing a precise micro-sensor system after application of a consistent load in the (1) intact state, (2) after compression fixation with a syndesmotic screw and (3) after anterior & (4) posterior malreduction of the syndesmosis.ResultsFollowing screw compression of the nondisplaced syndesmosis, dorsiflexion ROM was 99.7 ± 0.87% (mean ± standard error) of baseline ankle ROM. Anterior and posterior malreduction of the syndesmosis resulted in dorsiflexion ROM that was 99.1 ± 1.75% and 98.6 ± 1.56% of baseline ankle ROM, respectively. One-way ANOVA was performed showing no statistical significance between groups (p-value = 0.88).Two-way ANOVA comparing the groups with respect to both the reduction condition (intact, anatomic reduction, anterior displacement, posterior displacement) and the displacement order (anterior first, posterior first) did not demonstrate a statistically significant effect (p-value = 0.99).ConclusionMaximal dorsiflexion of the ankle is not required prior to syndesmotic fixation as no loss of motion was seen with compressive fixation in our cadaver model. Anterior or posterior syndesmotic malreduction following syndesmotic screw fixation had no effect on ankle dorsiflexion. Poor patient outcomes after syndesmotic malreduction may be due to other factors and not loss of dorsiflexion motion.Level of Evidence: IV