Supination External Rotation Ankle Fractures Research Articles

Dislocations deteriorate postoperative functional outcomes in supination-external rotation ankle fractures

PurposeTo assess the relationship between dislocation and functional outcomes in supination-external rotation (SER) ankle fractures. MethodsA retrospective case series study was performed on patients with ankle fractures treated surgically at a large trauma center from January 2015 to December 2021. The inclusion criteria were young and middle-aged patients of 18–65 years with SER ankle fractures that can be classified by Lauge-Hansen classification and underwent surgery at our trauma center. Exclusion criteria were serious life-threatening diseases, open fractures, fractures delayed for more than 3 weeks, fracture sites ≥2, etc. Then patients were divided into dislocation and no-dislocation groups. Patient demographics, injury characteristics, surgery-related outcomes, and postoperative functional outcomes were collected and analyzed. The functional outcomes of SER ankle fractures were assessed postoperatively at 1-year face-to-face follow-up using the foot and ankle outcome score (FAOS) and American orthopedic foot and ankle society score and by 2 experienced orthopedic physicians. Relevant data were analyzed using SPSS version 22.0 by Chi-square or t-test. ResultsDuring the study period, there were 371 ankle fractures. Among them, 190 (51.2%) were SER patterns with 69 (36.3%) combined with dislocations. Compared with the no-dislocation group, the dislocation group showed no statistically significant differences in gender, age composition, fracture type, preoperative complications with diabetes, smoking history, preoperative waiting time, operation time, and length of hospital stay (all p > 0.05), but a significantly higher Lauge-Hansen injury grade (p < 0.001) and syndesmotic screw fixation rate (p = 0.033). Moreover, the functional recovery was poorer, revealing a significantly lower FAOS in the sport/rec scale (p < 0.001). Subgroup analysis showed that among SER IV ankle fracture patients, FAOS was much lower in pain (p = 0.042) and sport/rec scales (p < 0.001) for those with dislocations. American orthopedic foot and ankle society score revealed no significant difference between dislocation and no-dislocation patients. ConclusionDislocation in SER ankle fractures suggests more severe injury and negatively affects functional recovery, mainly manifested as more pain and poorer motor function, especially in SER IV ankle cases.

Is just one screw really enough? Single- versus double-screw in the medial malleolus in supination-external rotation ankle fractures: A comparative biomechanical study using partially threaded cancellous screws

ObjectiveThe aim of this study is to investigate stiffness and the maximum load to failure values of single- and double-screw fixation of oblique medial malleolus fractures using partially threaded cancellous screws. Our hypothesis is that single-screw fixation of medial malleolus fractures after SER injuries provides similar stiffness when compared with double-screw fixation. DesignBiomechanical study. MethodsTwelve composite polyurethane synthetic right distal tibiae were used in the experiment. Oblique fractures of the medial malleolus were created with a band saw using a custom-made osteotomy guide to standardize the cuts in all models. Bone models were randomly separated into two groups and fixed with one (n = 6) or two (n = 6) 4.0 mm partially threaded cancellous screws placed perpendicular to the fracture line. These were tested by applying an offset axial tension at 10 mm/minute up to maximum load displacement, defined as subsidence of the medial malleolus fragment. Maximum load to failure was determined for the groups at the point where the curve ceased to be linear and suffered an inflection. Force versus displacement curves were obtained and recorded. The student's t-test for independent samples was used to compare stiffness (N / mm) and maximum load (N) between experimental groups, with a p value of < 0.05. ResultsThere were no significant differences in stiffness (p = 0.290) and maximum load (p = 0.191) among the two fixation constructs. Mean stiffness was 62.26 (±SD 21.11) N/mm for double-screw fixation group and 48.24 (±SD 22.40) N/mm for single-screw fixation group. Mean maximum load was 387.83 (±SD 115.78) N for double-screw fixation group and 306.64 (±SD 81.97) N for single-screw fixation group. ConclusionFixation with one 4.0 mm partially threaded cancellous screw was not shown to be biomechanically inferior to fixation with two 4.0 mm partially threaded cancellous screws in an oblique fracture of the medial malleolus, supporting previous clinical studies that have shown that one screw is sufficient for fractures of the medial malleolus.

Acute Deltoid Injury in Ankle Fractures: A Biomechanical Analysis of Different Repair Constructs

Category: Trauma; Ankle Introduction/Purpose: The importance of the deltoid ligament in the congruency of the tibiotalar joint is well known. The current trend is to repair it in cases of acute injuries in the context of ankle fractures, however, there is no information on how it should be reconstructed. The objective of this study was to compare different deltoid ligament repair types in an ankle fracture cadaveric model. Methods: 16 cadaveric foot-ankle-distal tibia specimens were used to conduct the study. All samples were prepared as a supination external rotation ankle fracture model. An axial load and cyclic axial rotations were applied on every specimen using a specifically designed frame. This test was performed without deltoid injury, with deltoid injury and finally with the ligament reconstructed. The reconstruction was performed in 4 different ways (anterior, posterior, middle, combined) using 4 specimens per group. Medial clear space (MCS) was measured for each condition on simulated weight-bearing and gravity stress radiographs. Reflective markers were utilized in tibia and talus, registering through a motion analysis system the kinematics, to record the tibiotalar uncoupling. Statistical analysis was performed using the SPSS software. Results: In all cases, the MCS increased significantly on gravity stress radiographs after damaging the deltoid ligament. There was no increase in the MCS on load radiographs. After repair, in all cases, the MCS was normalized. Kinematically, after damage the tibiotalar uncoupling increased significantly, decreasing after repair. All repairs significantly corrected the tibiotalar uncoupling, observing a significantly increased coupling effect (increased stiffness) with the combined repair. Conclusion: Our results show that deltoid repair recovers the tibiotalar coupling mechanism in an ankle fracture model. We suggest that the ideal repair should aim to repair the middle aspect of the deltoid ligament. The combined repair may lead to postoperative stiffness. Clinical studies are needed to prove these results and show clinically improved outcomes.

Acute Deltoid Injury in Ankle Fractures: A Biomechanical Analysis of Different Repair Constructs.

The importance of the deltoid ligament in the congruency and coupling of the tibiotalar joint is well known. The current trend is to repair it in cases of acute injuries in the context of ankle fractures; however, there is limited information on how it should be reconstructed. The objective of this study was to compare different deltoid ligament repair types in an ankle fracture cadaveric model. Sixteen cadaveric foot-ankle-distal tibia specimens were used. All samples were prepared as a supination external rotation ankle fracture model. Axial load and cyclic axial rotations were applied on every specimen using a specifically designed frame. This test was performed without deltoid injury, with deltoid injury, and after repair. The reconstruction was performed in 4 different ways (anterior, posterior, middle, and combined). Medial clear space (MCS) was measured for each condition on simulated weightbearing (WB) and gravity stress (GS) radiographs. Reflective markers were used in tibia and talus, registering the kinematics through a motion analysis system to record the tibiotalar uncoupling. After deltoid damage, in all cases the MCS increased significantly on GS radiographs, but there was no increase in the MCS on WB radiographs. After repair, in all cases, the MCS was normalized. Kinematically, after deltoid damage, the tibiotalar uncoupling increased significantly. All isolated repairs achieved a similar tibiotalar uncoupling value as its baseline condition. The combined repair resulted in a significant decrease in tibiotalar uncoupling. Our results show that deltoid repair recovers the tibiotalar coupling mechanism in an ankle fracture model. Isolated deltoid repairs recovered baseline MCS and tibiotalar uncoupling values. Combined repairs may lead to overconstraint, which could lead to postoperative stiffness. Clinical studies are needed to prove these results and show clinically improved outcomes. This study helps in finding the optimum deltoid repair to use in an acute trauma setting.

Indications and Interpretation of Stress Radiographs in Supination External Rotation Ankle Fractures.

Introduction In supination external rotation (SER) ankle fractures with an intact medial malleolus, stability hinges upon the competence of the deltoid ligament. The purpose of this study is to define the indications and establish criteria for a positive stress radiograph. Methods This is a prospective study of 27 isolated SER lateral malleolar fractures with a reduced ankle mortise. Pain and swelling were noted about the medial ankle, followed by an ultrasound to evaluate the integrity of the deltoid ligament. Static and stress radiographs were performed on both the fractured and contralateral ankles. Results Fourteen patients were normal on ultrasound examination, eight had partial tears, and five had full-thickness tears. The difference in the level of pain to palpation postero-medially between the complete tear (7 +/- 1) and the partial tear (1.3 +/- 2.4) group was significant (p < .001). The negative predictive values for medial swelling and tenderness were 93% and 100%, respectively. Sensitivity and specificity for medial clear space on stress radiograph (fracture (fx)) > 5.0 mm were both 100% while a 2.5 mm or greater change to the contralateral side yielded a sensitivity of 100% and specificity of 95%. Conclusion The lack of significant medial pain, as well as swelling, implies the absence of a complete ligament tear and eliminates the need for stress examination. Conversely, the presence of medial signs of injury is suggestive, but not pathognomonic for a complete deltoid tear. Medial clear space (MCS) variability prompts to recommend a minimum of 2.5 mm on stress radiographs compared to the contralateral side as indirect evidence for a complete tear of the deltoid ligament.

Lateral talar subluxation (LTS) in SER ankle fractures is more responsive than medial clear space widening: A cadaveric biomechanical study

Category: Ankle; Trauma Introduction/ Purpose: Supination-external rotation (SER) ankle fractures are characterized by posterolateral translation and external rotation. In isolated fibula fracture SER variants, medial soft tissue structure incompetence can be identified with medial clear space (MCS) widening or with lateral talar subluxation (LTS), frequently obtained on stress view imaging. This assessment is a key determination of which patients may require surgical management to restore ankle joint stability. Current radiographic studies demonstrated increased sensitivity and specificity of LTS versus MCS which may be due to increased rotational movement occurring in the direction of the talar displacement. Biomechanical data has not yet been established. The purpose of this study was to investigate MCS and LTS displacements in a cadaveric biomechanical study to confirm this rotational movement principle in a controlled setting. Methods: An open approach was utilized to surgically create an SER isolated fibula fracture in five below-knee cadaveric specimens. Open anteromedial and lateral ankle approaches were created for visualization of the medial and lateral structures, also allowing direct measurement of the MCS and LTS with a ruler. There was no ankle instability prior to injury, MCS and LTS were zero in each specimen prior to experimental model creation. An SER-pattern fibular osteotomy was made with an oscillating saw. The superficial and deep deltoid were then released from the medial malleolus, and the foot was displaced maximally creating an SER-4b variant ankle fracture. The MCS and LTS were then measured. Differences were analyzed using a paired Student’s t-test. Effect size (Cohen’s d) was measured to characterize statistical significance and determine relative importance in the degree of change. Results: There was no underlying ankle stability, deformity, or arthritis in any of the 5 cadaveric ankle specimens. In our simulated SER-4b ankle fractures, the mean MCS widening using medial landmarks was 7.2 mm (+/- 1.3mm). The mean lateral displacement utilizing the LTS landmarks was 11.2mm (+/- 1.3mm). The difference between medial and lateral displacement was found to be statistically significant (p = 0.0067, 95% CI [1.85, 6.15]). Cohen’s d was equal to 3.1 (95% CI [1.24, 4.90]), demonstrating a large effect size, showing the mean to be different by 3 standard deviations. The increase in mean lateral displacement was 43% greater when compared to the mean medial displacement. Conclusion: In this cadaveric study, LTS displacement was significantly greater than MCS widening following simulation of SER type IV ankle fracture injuries. The effect size of 3.1 confirms statistical significance. This data supports that talus external rotation is a significant factor in SER pattern displacement. The rotational moment arm is largest laterally with external rotation, and posterolateral displacement. Our study supports the idea of measuring the LTS radiographically as a marker to assist in surgical decision-making. Further characterization of the displacement pattern of SER injuries will be helpful to assist surgical decision- making in these common ankle injuries.

Measuring Deltoid Insufficiency after Supination-External Rotation Ankle Fracture with Lateral Talar Subluxation on Gravity Stress View

Category: Trauma; Ankle Introduction/Purpose: Supination-external rotation (SER) variant ankle fracture is common, and identifying the unstable SER variants requiring surgery has been controversial. Stress view radiographs are frequently obtained to assist in decision-making. Measurement of the medial clear space (MCS) is used to determine medial structure integrity. SER variant ankle injuries are characterized by talus external rotation, and posterolateral translation causing a posterior displaced distal fibula fracture, with possible medial and posterior injury at further subluxation events. We propose that the MCS measurement is flawed by measuring from the point of rotational pivoting. Measurement of lateral displacement of the lateral talus versus the tibial plafond will be a more sensitive measurement tool for an injury mechanism characterized by external rotation and posterolateral subluxation. Methods: IRB-approved, retrospective review of ankle injury radiographs for acute SER-variant isolated lateral malleolar fractures during a 3-year consecutive period. Patients were included if they had a gravity-stress view (GSV) evaluation. Patients were excluded for different fracture morphology, pediatric fractures, no GSV films, or prior history of ankle or foot arthritis or trauma. A priori power analysis was performed demonstrating 32 patients would be required to detect a change in 2mm. 102 patients underwent analysis. GSV were analyzed with measurements taken of the medial clear space (MCS), superior clear space (SCS), and we propose two novel measurements of lateral talus subluxation (LTS) by comparison to the anterior ankle syndesmosis marked by a vertical line at the tibial plafond. Standardized measurements were acquired by foot-and-ankle fellowship-trained orthopaedic surgeons and musculoskeletal radiologists. ICC data was obtained. Surgeons separately provided blinded decisions- for-surgery which patients appeared to have ankle instability requiring surgical stabilization. Results: Measurements were performed for 102 patients, there were no significant differences in baseline demographics. There was a statistically significant increase in mean MCS, SCS, and LTS within the operative group (MCS 7.3 vs 5, p=0.005, SCS 4.6 vs 3.9, p=0.02, LTS 6.1 vs 2.9, p &lt;0.001) with the LTS having the highest statistical significance. Pearson correlation analysis demonstrated positive and significant correlations between MCS and SCS (0.43, 0.37, P&lt;0.001), MCS and LTS (0.51, p&lt;0.001). MCS &gt;=5mm had a sensitivity of 95% and specificity of 60% in our cohort, LTS &gt;4mm demonstrating the same sensitivity (95%) with improved specificity to 75%. Receiver-operator-characteristic analysis for MCS vs LTS demonstrates an area under the curve (AUC) 0.786 for MCS &gt;4 versus LTS (AUC) 0.918. Conclusion: The LTS measurement is superior to MCS measurement as a surrogate for medial ankle structure stability. We propose that ankle joint subluxation can be more accurately identified by measuring nearer to the point of maximal talar displacement in an external rotation and posterolaterally displacing injury pattern. The LTS measurement elevation &gt;4mm was found to be superior to the MCS measurement &gt;4mm in all categories, with high sensitivity and specificity, and superior performance in ROC analysis. We propose this will be a useful tool for clinicians when evaluating SER variant ankle fractures.

Measuring Deltoid Insufficiency After Supination-External Rotation Ankle Fracture With Lateral Talar Subluxation on Gravity Stress View.

Stress-view radiographs are frequently obtained to evaluate supination-external rotation (SER) variant ankle fractures. Measurement of the ankle medial clear space (MCS) is a surrogate of medial structure integrity as part of overall ankle stability. Measurement of the lateral talus displacement with respect to the incisura may be a sensitive and specific method to assess joint subluxation. Retrospective review of acute SER-variant isolated lateral malleolar fractures with gravity stress views (GSVs) were performed for 103 patients. GSV analysis was performed with standardized measurements of the MCS, superior clear space (SCS), and 2 new novel measurements of lateral talus subluxation (LTS). Decision for surgery was obtained by surgeons who reviewed masked injury radiographs for predictive performance analysis of the LTS vs MCS. MCS, SCS, and LTS measurements were performed on 103 patients. Mean MCS, SCS, and LTS within the operative group was increased. MCS ≥5 mm and LTS >4 mm had equal sensitivity (95%), with higher specificity for LTS (75% vs 60%). Receiver operating characteristic analysis demonstrates an area under the curve of 0.786 for MCS ≥5 mm vs 0.918 for LTS >4 mm. We found LTS to be superior to MCS for medial ankle structure stability on gravity stress views of SER-variant ankle fractures. We propose this as a useful tool for clinicians to consider when evaluating SER-variant ankle fractures. Level II, prospective comparative study of radiographs.

A systematic review of ankle fracture-dislocations: Recent update and future prospects.

BackgroundAnkle fracture-dislocations are one of the most severe types of ankle injuries. Compared to the simple ankle fractures, ankle fracture-dislocations are usually more severely traumatized and can cause worse functional outcomes. The purpose of this study was to review the previous literatures to understand the anatomy, mechanisms, treatment, and functional outcomes associated with ankle fracture-dislocations.MethodsThe available literatures from January 1985 to December 2021 in three main medical databases were searched and analyzed. The detailed information was extracted for each article, such as researchers, age, gender, groups, type of study, type of center research, level of evidence, significant findings, study aim, cause of injury, time from injury to surgery, type of fracture, direction of dislocation, follow-up, postoperative complications and functional evaluation scores.ResultsA total of 15 studies (1,089 patients) met the inclusion criteria. Only one study was a prospective randomized trial. The top-ranked cause of injury was high-energy injury (21.3%). Moreover, the most frequent type of fracture in ankle dislocations was supination-external rotation (SER) ankle fracture (43.8%), while the most common directions of dislocation were lateral (50%) and posterior (38.9%).ConclusionsCollectively, most ankle fracture-dislocations are caused by high-energy injuries and usually have poor functional outcomes. The mechanism of injury can be dissected by the ankle anatomy and Lauge-Hansen's classification. The treatment of ankle fracture-dislocations still requires more detailed and rational solutions due to the urgency of occurrence, the severity of injury, and the postoperative complications.

The Anatomy and Function of the Individual Bands of the Deltoid Ligament-and Implications for Stability Assessment of SER Ankle Fractures.

Background:Deltoid ligament injury occurs often with supination-external rotation (SER) ankle trauma. SER fibula fractures with concomitant deltoid ligament injury are considered unstable—requiring operative fixation. Recent studies have questioned this general practice with emphasis on better defining the medial side ankle ligamentous injury. The function of the individual bands of the deltoid ligament, and the interplay between them, are not fully understood. We undertook this study to develop a better understanding of these complex ligamentous structures and ultimately aid assessment and treatment choice of SER ankle fractures with concomitant deltoid ligament injuries.Methods:Ten fresh-frozen cadaveric foot and ankle specimens were studied. We identified the various ligament bands and did a functional analysis by assessment of ligament length and tension at predefined angles of ankle dorsi-plantarflexion combined with valgus/varus and rotation. The results were determined by manual evaluation with calipers and goniometers, manual stress, and direct visualization.Results:We recorded primarily 5 different bands of the deltoid ligament: the tibionavicular (TNL; 10/10) tibiospring (TSL; 9/10), tibiocalcaneal (TCL; 10/10), deep anterior tibiotalar (dATTL; 9/10), and deep posterior tibiotalar (dPTTL; 10/10) ligaments. The tibiospring ligament was tense in plantarflexion, while the tibiocalcaneal and deep posterior tibiotalar ligaments were tense in dorsiflexion. The superficial layer ligaments and the deep anterior tibiotalar ligament length and tension were largely affected by changes in varus/valgus and rotation. The deep posterior tibiotalar ligament length and tension was altered predominantly by changes in dorsi-plantarflexion; varus/valgus positioning had a minor effect on this band.Conclusions:We confirmed the finding of previous studies that dorsi-plantarflexion affects the tensile engagement of the separate ligament bands differently. Likewise, combined movements with varus/valgus and rotation seem to affect the separate ligament bands differently. Our results suggest that the TNL, TSL, and dATTL are at risk of injury, whereas the TCL and particularly the dPTTL are protected in the event of an SER-type ankle fracture mechanism of injury.Level of EvidenceLevel V, cadaveric study.

Diagnostic tools to evaluate ankle instability caused by a deltoid ligament rupture in patients with supination-external rotation ankle fractures: A systematic review and meta-analysis

AimSupination-external rotation (SER) ankle fractures account for the majority of ankle fractures and can be divided into stable or unstable fractures, based on the state of the deltoid ligament. The objective of this review was to appraise the available literature concerning diagnostic tools to evaluate deltoid ligament integrity in patients with SER-type ankle fractures. MethodsA comprehensive literature search of Pubmed and Embase was performed up to December 2020. The outcome measures were sensitivity, specificity and positive and negative predictive value of the diagnostic tools. A meta-analysis was performed to obtain an overview of sensitivity, specificity and area under the curve (AUC). The methodological quality of the articles was evaluated using Quality Assessment of Diagnostic Accuracy Studies. ResultsA total of 12 studies investigating tools for deltoid ligament rupture in patients with SER-type ankle fractures were included. The present study found sensitivity (and specificity) ranges of 0.20-0.90 (and 0.38-0.97) for clinical features, Magnetic Resonance Imaging (MRI) 0.57-0.85 (and 0.81-1.00), ultrasonography 1.00 (and 0.89-1.00), Malleolar Medial Fleck Sign (MMFS) 0.25 (and 0.99), conventional ankle mortise radiography 0.33-0.57 (and 0.60-0.94), gravity stress radiography 0.71-1.00 (and 0.72-0.88) and manual stress ankle radiography 0.65-1.00 (and 0.00-0.77). The largest AUC was found for ultrasonography, followed by MMFS, gravity stress radiography and MRI. ConclusionUltrasonography and gravity stress radiography seem the most accurate diagnostic tools to evaluate deltoid ligament integrity. To strengthen this conclusion, future research should use an identical reference test to ensure comparability of results. Nevertheless, present study is of high value to close the knowledge gap about which presently available diagnostic tool is to be preferred to evaluate deltoid ligament integrity in patients with SER-type ankle fractures.

Syndesmosis fixation in supination-external rotation ankle fractures. Long-Term results of a prospective randomised study

BackroundThe clinical relevance and treatment of syndesmosis injury in supination-external rotation (SER) ankle fractures are controversial. MethodsAfter malleolar fixation 24 SER 4 ankle fracture patients with unstable syndesmosis in external rotation stress test were randomised to syndesmosis transfixation with a screw (13 patients) or no fixation (11 patients). Mean follow-up time was 9.7 years (range, 8.9–11.0). The primary outcome measure was the Olerud-Molander Ankle Outcome Score (OMAS). Secondary outcome measures included ankle mortise congruity and degenerative osteoarthritis, 100-mm visual analogue scale for function and pain, RAND 36-Item Health Survey, and range of motion. ResultsMean OMAS in the syndesmosis transfixation group was 87.3 (SD 15.5) and in the no-syndesmosis-fixation group 89.0 (SD 16.0) (difference between means 1.8, 95% CI −10.4–14.0, P = 0.76). There were no differences between the two groups in secondary outcome measures. ConclusionWith the numbers available, SER 4 ankle fractures with unstable syndesmosis can be treated with malleolar fixation only, with good to excellent long-term functional outcome.

The Role of Deep Deltoid Ligament in Ankle Fracture Stability: A Biomechanical Cadaveric Study

Category:Ankle; Basic Sciences/Biologics; TraumaIntroduction/Purpose:Supination-external rotation (SER) injuries make up 80% of all ankle fractures. SER stage 2 injuries (AITFL and Weber B) are considered stable. SER stage 3 injury includes disruption of the posterior malleolus (or PITFL). In SER stage 4 there is either medial malleolus fracture or deltoid injury. SER 4 injuries have been considered unstable, requiring surgery. The deltoid ligament is a key component of ankle stability, but clinical tests to assess deltoid injury have low specificity. This biomechanical cadaveric study specifically investigates the role of the components of the deep deltoid ligament in the stabillity of SER ankle fractures.Methods:In the first phase of the study, three specimens were utilised to standardise dissection of the deltoid ligament and creation and fixation of SER ankle fracture. In phase two, four matched pairs (8 specimens) were tested using this standardised protocol (Figure1). Specimens were sequentially tested for stability when axially loaded with a custom rig with up to 750N. Specimens were tested with: ankle intact; lateral injury (AITFL and Weber B); additional posterior injury (PITFL); additional anterior deep deltoid; additional posterior deep deltoid; lateral side ORIF. Clinical photographs and radiographs were recorded at each stage. In addition, dynamic stress radiographs were performed after sectioning the deep deltoid and following fracture fixation to assess talar tilt in eversion.Results:All specimens behaved in an identical manner when subjected to this standardised protocol. When the posterior deep deltoid ligament was intact, the ankle remained stable when loaded and showed no talar tilt on dynamic stress test. Once the posterior deep deltoid ligament was sectioned, there was demonstrable instability in all specimens. Surgical stabilisation of the lateral side using standard technique with a plate prevented talar shift but not talar tilt. In adequately stabilised ankle specimens, there was no loss of fixation on axial loading.Conclusion:This biomechanical cadaveric experiment demonstrates that under the standardised test conditions, all SER fracture ankle specimens with an intact posterior deep deltoid ligament behaved as stable injuries. The posterior portion of the deep deltoid ligament is a crucial structure in conferring stability to SER stage 4 injuries. The clinical implication of this is that when the posterior deep deltoid ligament is intact, SER fractures may be managed without surgical intervention in a plantigrade cast. We also conclude that without immobilisation, the talus may tilt in the mortise risking long-term deltoid incompetence.

Necessity of Interfragmentary Lag Screws in Precontoured Lateral Locking Plate Fixation for Supination-External Rotation Lateral Malleolar Fractures

Interfragmentary lag screws, protected by a plate, have been applied for many years in the treatment of supination-external rotation (SER) ankle fractures. Recently, similar biomechanical stability was found between fixation completed with a plate and lag screw and a plate alone. The aim of this study was to determine whether interfragmentary lag screws are necessary during precontoured lateral locking plate fixation for SER lateral malleolar fractures. A prospective randomized controlled trial of 76 patients with unilateral Lauge-Hansen SER lateral malleolar fractures was conducted. The patients were randomly treated either with or without the use of interfragmentary lag screws with precontoured lateral locking plate fixation. Clinical outcomes were assessed using the Olerud-Molander Ankle Score and a visual analog scale for pain. Radiologic outcomes were assessed based on the Kellgren and Lawrence scale score, incongruity of the ankle joint, and type of fracture healing. Sixty-nine patients completed 12 months of follow-up. There was no significant difference between the 2 groups with regard to clinical outcomes at 3 and 12 months after surgery and radiologic outcomes at 12 months after surgery. All patients in both groups achieved primary bone healing. The results of this study suggest that with precontoured lateral locking plate fixation, the use of interfragmentary lag screw is not essential in the treatment SER lateral malleolar fractures. Level I, prospective randomized study.

Medial tenderness revisited: Is medial ankle tenderness predictive of instability in isolated lateral malleolus fractures?

IntroductionDetermining deltoid ligament incompetence in supination external rotation (SER) injuries commonly relies on stress radiography, given several studies demonstrating low predictive value of physical examination. Stress radiography can be difficult to obtain and may result in suboptimal radiographs with equivocal determination of stability. This study revisits the concept of medial ankle tenderness and its association with mortise instability. MethodsPatients who presented with an isolated lateral malleolus fracture underwent prospective data collection. VAS scores were recorded with palpation at the lateral malleolar fracture site, anterior deltoid ligament, and posterior deltoid ligament. Three non-weightbearing radiographs of the ankle and a gravity stress view were obtained. Statistical analysis was performed to determine a correlation between tenderness and instability defined as MCS widening > 4 mm on gravity stress x-ray. Results51 patients met inclusion criteria. Group I (stable) and Group II (unstable) demonstrated no difference in tenderness over the lateral malleolus (p = 0.94) or anterior deltoid (p = 0.12), but patients in Group II reported significantly more tenderness over the posterior deltoid (p = 0.03). Taking the higher pain score from either anterior or posterior deltoid palpation, patients with unstable ankle fractures reported significantly more tenderness with medial palpation (p = 0.02). The relative risk of having an unstable ankle fracture with any tenderness to palpation over either the anterior or posterior deltoid ligament was 1.77 (95% CI 1.03 - 3.06, P = 0.039). When comparing no pain versus the presence of any pain with palpation medially, the sensitivity for any medial tenderness to detect an unstable ankle fracture was 0.76 (specificity 0.59, PPV 0.79, NPV 0.56). ConclusionPatients with any medial tenderness were at significantly higher risk of having an unstable SER ankle fracture in this study, but strict reliance on the presence or absence of medial tenderness without stress radiographs would lead to an unacceptable number of both false positive and false negative determinations of instability. However, our findings suggest that medial tenderness is associated with instability. The 0.79 PPV of any medial tenderness for instability may be useful to cast doubt on equivocal stress radiography and prompt surgeons to repeat stress radiography or shorten the interval for radiographic follow up. Level of evidenceDiagnostic study, Level II-1 (development of diagnostic criteria on basis of consecutive patients [with universally applied reference “gold” standard]).

Medial clear space volume on cone beam CT scan offers objective measurement of congruency in supination external rotation ankle fractures in a cadaver model.

We performed a volume analysis of gravity stress (GS) and simulated weight bearing (WB) CBCT scans of a cadaveric supination external rotation (SER) ankle fracture model. An AO supination external rotation 44B3.1 ankle fracture was simulated in 6 human cadavers, each serving as its own control. MCS volume (mm3) was measured on GS and WB CBCT scans. Paired t-tests were used to compare the MCS volume for control versus experimental conditions for GS and WB conditions, and means ± standard deviation are presented. MCS on GS CBCT was greater for the experimental (1,540.15±374.8) versus control (984.5±226.5) groups (P=0.004), and MCS on WB CBCT was also greater for the experimental (1,225.57±274.1) versus control (1,059.40±266.6) groups (P=0.05). MCS on GS CBCT was greater for the experimental group compared to both WB CBCT controls (P=0.005) and WB CBCT experimental group (P=0.04). Additionally, MCS on WB CBCT was greater for the experimental group compared to GS CBCT controls (P=0.002), however there was no statistically significant difference in MCS on GS CBCT for controls versus WB CBCT for controls (P=0.08). MCS volume increased on WB CBCT scans using a cadaveric SER ankle fracture model.

Systematic Review of Stress Radiographic Modalities Stability Assessment in Supination External Rotation Ankle Fractures.

Background:Isolated distal fibular fractures resulting from supination external rotation (SER) injuries without evidence of obvious talar shift on standard radiographs present a diagnostic dilemma for clinicians. The status of the deep deltoid ligament, the main stabilizer of the ankle joint, is assessed by an increase in medial clear space (MCS) on radiographs. Therefore, these injuries can be either stable or unstable. In recent years, considerable clinical and research efforts have been made to determine ankle stability following SER fracture. The purpose of this systematic review was to evaluate and compare the role of different stress radiograph modalities in assessing stability of the ankle with SER fractures with no obvious talar subluxation on standard radiographs.Methods:The electronic databases MEDLINE, EMBASE, Ovid, Cochrane Central, CINAHL, and Google Scholar were searched from January 2000 to January 2018 to identify literature relating to radiologic assessment of stability of SER ankle fractures.Results:Our literature search revealed 10 peer-reviewed articles that fulfilled inclusion criteria. This yielded a total of 698 patients. The systematic review found 3 broad categories of radiographic investigations in the assessment of ankle joint stability: external rotation (ER) stress radiographs, gravity stress views (GSV), and weightbearing (WB) radiographs. Proponents of WB radiographs have demonstrated how axial load can normalize ankle joint alignment in cases of proven instability. There was a consistently high grade of evidence for using a medial clear space (MCS) value of more than 4 to 5 mm to indicate an unstable ankle following SER fracture.Conclusion:In conclusion, the results of this systematic review support an MCS value of less than 4 to 5 mm as a good indicator of stability, regardless of choice of stress imaging modality. These patients can be allowed early weightbearing with expected good functional outcomes. Recent published literature favors WB stress radiographs as a reliable and safe technique for assessing stability in SER ankle fractures. However, it should be kept in mind that this is based on studies with relatively low grades of evidence.Level of Evidence:Level II, systematic review of variable quality studies.

Arthroscopic Reduction and Minimally Invasive Surgery in Supination–External Rotation Ankle Fractures: A Comparative Study With Open Reduction

To describe an algorithm for arthroscopic reduction and minimally invasive surgery (ARMIS) and compare the surgical outcomes with standard open reduction-internal fixation (ORIF) for the treatment of supination-external rotation (SER) ankle fractures. The inclusion criteria for this study were patients aged 16years or older, the presence of a unilateral SER fracture, and injuries less than 2weeks old. We retrospectively identified patients with SER fractures who underwent ORIF from January 2008 to December 2011 or ARMIS from January 2012 to December 2015. Data collected in December 2013 for the ORIF group and in December 2017 for the ARMIS group were compared. The algorithm for ARMIS was minimally invasive plating for lateral malleolar fractures first, followed by ankle arthroscopy for detection of syndesmotic injuries and then arthroscopic reduction of medial malleolar fractures or mini-open repair of the deltoid ligament. The talocrural angle, fibular length, tibiomedial malleolar angle, medial clear space, and tibiofibular clear space were measured radiographically. Functional evaluations included the visual analog scale pain score, American Orthopaedic Foot & Ankle Society ankle-hindfoot scales, and range of motion of bilateral ankles. Complications and reoperations were recorded for comparison. A total of 105 patients with SER fractures, 65 in the ARMIS group and 40 in the ORIF group, were included. Significantly lower incidences of complications (7.7% vs 27.5%, P= .006) and reoperations (1.5% vs 12.5%, P= .029) were found in the ARMIS group than in the ORIF group. More syndesmotic injuries were detected in the ARMIS group than in the ORIS group (80% vs 57.5%, P= .021). The visual analog scale pain score was significantly lower on day 3 postoperatively in the ARMIS group than in the ORIS group (1.96 ± 1.18 vs 2.83 ± 1.07, P= .027). The postoperative stay was shorter in the ARMIS group than in the ORIF group (3.66 ± 1.39days vs 4.46 ± 2.23days, P= .024). The operative time was longer in the ARMIS group than in the ORIS group (105.22 ± 27.13minutes vs 93.59 ± 22.79minutes, P= .038). A longer fluoroscopic time (0.43 ± 0.25minutes vs 0.17 ± 0.07minutes, P < .001) and a higher dose of irradiation (1,216.46 ± 603.99μGy vs 389.38 ± 217.89μGy, P < .001) were observed in the ARMIS group. No significant differences in radiographic measurements were found between the operative and nonoperative ankles in both groups. Our algorithm and the ARMIS techniques may be a safe, reliable, and effective option in the treatment of SER fractures. ARMIS achieves promising surgical outcomes with less early postoperative pain, a shorter postoperative stay, and lower incidences of complications and reoperations compared with ORIF. However, the operative time is longer and the irradiation dose is higher with the ARMIS techniques. Level III, retrospective comparative study.

Posterior Malleolus Fracture Displacement Is Associated with Rotational Ankle Fracture Stability in Patients Without Medial Malleolar Fractures.

The optimal method for the determination of ankle stability remains controversial in rotational ankle fractures without medial bony injury. The purposes of this study were to (1) evaluate whether posterior malleolar (PM) fracture displacement is associated with deltoid ligament injury in supination-external rotation (SER) ankle fractures and (2) compare the diagnostic accuracy of PM displacement and magnetic resonance imaging (MRI) evaluation of the deep deltoid ligament in identifying fractures with deltoid ligament incompetence. Patients with rotational bimalleolar injuries containing lateral malleolar and PM fractures without bony medial injury were included. After operative lateral and PM fixation, an external rotation stress test was performed to evaluate deltoid ligament stability. Operative dictations were reviewed to confirm injury pattern, stability on stress test, and visual inspection of the deltoid ligament. Maximum PM displacement was assessed on lateral X-ray. Pre-operative MRI of the ankle was performed following closed reduction and splinting. The final cohort consisted of 13 trimalleolar equivalent fractures (torn deltoid ligament) and 20 bimalleolar fractures (medial malleolus and deltoid ligament intact). Average PM displacement was significantly higher for SER trimalleolar equivalent patterns when measured on lateral X-ray. The sensitivity of detecting trimalleolar equivalent fracture was higher on all reported X-ray findings than the sensitivity obtained by the reported MRI findings of deltoid ligament injury. PM displacement on X-ray is a useful adjuvant along with external rotation stress radiography and MRI evaluation of deep deltoid integrity to distinguish between stable and unstable fracture patterns and thus helps facilitate treatment decisions.

Deltoid Ligament Rupture in Ankle Fracture: Diagnosis and Management.

The last stage of a supination-external rotation ankle fracture involves either transverse fracture of the medial malleolus or rupture of the deltoid ligament. When the deltoid ligament ruptures, a "bimalleolar equivalent" ankle fracture occurs, and the surgeon is presented with several diagnostic and therapeutic challenges. In the native ankle, the deltoid ligament provides restraint to eversion and external rotation of the talus on the tibia. In bimalleolar equivalent ankle fractures, there is often gross medial instability even after fibular reduction. Retraction of the deltoid with subsequent healing in a nonanatomic position theoretically may cause instability, persistent medial gutter pain, and loss of function with risk of early arthritis. In mild cases, deltoid injury may not be obvious, and potential diagnostic techniques include preoperative and intraoperative stress radiography, MRI, and ultrasonography. The most common injury pattern is avulsion from the medial malleolus, and most current repair techniques involve direct repair of the capsular and deltoid injuries involving suture anchors in the medial malleolus and imbrication of the superficial and deep deltoid fibers. To date, there is limited evidence of superior clinical outcomes with the addition of deltoid repair compared with open reduction and internal fixation of the fibula alone.