An evaluation of the Herscovici classification for fractures of the medial malleolus

Electric scooter injuries: Incidence and injury patterns at a level I trauma center

PURPOSE

Electric scooters (e-scooters) have become an increasingly popular mode of public transportation in recent years. As the incidence of related injuries rises, it is important to understand specific fracture patterns unique to e-scooters and electric bikes (e-bikes) to help guide management. The purpose of this study was to review the prevalence and describe specific fracture patterns of e-scooter and e-bike related injuries at the busiest level 1 trauma center in the borough of Manhattan.

METHODS

Chart review to determine mechanism of injury was performed on all patients for whom an orthopedic consult was requested from 1/1/2021 to 12/31/2021. All patients whose injuries were sustained due to an e-scooter or e-bike were further reviewed for demographics, injury characteristics including fracture pattern, and definitive injury management. Any patients who had an orthopedic consult placed for a reason other than an acute injury were excluded. Descriptive statistics are reported as frequency (percentage) for categorical variables and means for continuous variables.

RESULTS

Of the 1815 orthopedic consults requested, 1357 (74.8%) were for acute injury management. Of those with acute injuries, 119 (8.8%) sustained 136 e-scooter or e-bike related injuries. There were 92 (77.3%) males at an average age of (33.8 ± 15.7) years. Approximately one-fifth of all patients presented in June 2021 (26, 21.8%). There was a 9.2% rate of open fractures. The 136 injuries were evenly split between the upper and lower extremities, with 57 (47.9%) upper extremity, 57 (47.9%) lower extremity injuries, and 5 (4.2%) concomitant upper and lower extremity injuries. The most common fracture patterns were ankle fractures (16, 11.7%), followed by tibial shaft (14, 10.2%), tibial plateau (13, 9.5%), and radial head fractures (11, 8.0%). There was a 33.3% incidence of associated posterior malleolar fractures in the spiral tibial shaft fractures, 31.0% of posterior malleolar involvement and 18.8% of isolated vertical medial malleolar fractures in the ankle fractures, and 61.5% of posterior comminution in the tibial plateau fractures.

CONCLUSION

E-scooter and e-bike related injuries have a high incidence of tibial shaft fractures, ankle fractures, tibial plateau fractures, and radial head fractures. There should be a high index of suspicion for posterior and medial involvement in lower extremity fractures sustained due to e-scooter or e-bikes. Identifying specific fracture patterns seen in e-scooter and e-bike related mechanisms will help guide management of these injuries.

Effect of coronal fracture angle on the stability of screw fixation in medial malleolar fractures: A finite element analysis

Malleolar screw fixation is the most widely used treatment method for medial malleolar (MM) fractures. Here, although buttress plate fixation is advocated for vertical MM fractures, the angular discrimination between oblique and vertical MM fractures is still not fully understood. The purpose of this study is to test the adequacy of screw fixation in MM fractures with different angles and determination of a ‘critical fracture angle’ to guide surgeons in the decision-making for screw fixation for MM fractures by utilizing an advanced engineering simulation approach. In addition to loading of the healthy tibia structure, various cases of the MM fracture double screw fixation (14 simulation scenarios in total with fracture angles between 30° and 90°, in 5° increments) were considered in this research and their static loading conditions just after fixation operation were simulated through nonlinear (geometric and contact nonlinearity) finite element analysis (FEA). Patient-specific computed tomography scan data, parametric three-dimensional solid modelling and finite element method (FEM) based engineering codes were employed in order to simulate the fixation scenarios. Visual and numerical outputs for the deformation and stress distributions, separation and sliding behaviours of the MM fracture fragments of various screw fixations were clearly exhibited through FEA results. Minimum and maximum separation distances (gap) of 3.75 and 150.34 µm between fracture fragments at fracture angles of 30° and 90° were calculated respectively against minimum and maximum sliding distances of 25.87 and 41.37 µm between fracture fragments at fracture angles of 90° and 35°, respectively. The FEA results revealed that while the separation distance was increasing, the sliding distance was decreasing and there were no distinct differences in sliding distances in the scenarios from fracture angles of 30°–90°. The limitations and errors in a FEA study are inevitable, however, it was interpreted that the FEA scenarios were setup in this study by utilizing acceptable assumptions providing logical outputs under pre-defined boundary conditions. Finally, the fracture healing threshold for separation and/or sliding distance between fracture fragments was assigned as 100 µm by referring to previous literature and it was concluded that the screws fixed perpendicular to the fracture in a MM fracture with more than 70° angle with the tibial plafond results in a significant articular separation (>100 µm) during single-leg stand. Below this critical angle of 70°, two screws provide sufficient fixation.

Evaluation of ankle fracture classification systems in 193 trimalleolar ankle fractures

Purpose

Different classification systems have been developed for ankle fractures. In recent years, the posterior malleolus has gained in importance and led to computed tomography (CT)-based classification systems. The aim of the study was to analyse their reliability, fracture patterns and influence on treatment strategy.

Methods

Patients with a trimalleolar ankle fracture treated between 2011 and 2020 with preoperative radiographs and CT images were included. The blinded images were independently classified by three reviewers according to the AO/OTA, Herscovici, Bartoníček, Mason and Haraguchi classifications. The interobserver reliability was calculated by Fleiss' kappa (κ). CT images were analysed to determine the dimensions of the posterior malleolus fragments. Patient registries were reviewed regarding the treatment data.

Results

A total of 193 patients were included. The AO/OTA classification showed almost perfect inter- and intraobserver reliability (Fleiss’ κ = 0.86, 95% CI 0.82–0.90). Regarding the posterior malleolus, the Bartoníček classification demonstrated the highest reliability (Fleiss’ κ = 0.78, 95% CI 0.73–0.83). The Herscovici classification only reached moderate reliability for medial malleolus fractures (Fleiss' κ = 0.59, 95% CI 0.54–0.65). There was a trend towards direct fixation of the posterior malleolus in the last 3 years of the observation period (OR: 2.49, 95% CI 1.03–5.99).

Conclusion

In trimalleolar ankle fractures, the AO/OTA classification is a reliable system to characterize the type of fracture, but it fails to provide solid information about the posterior malleolus. Nowadays, treatment recommendations for trimalleolar ankle fractures focus on the configuration of the posterior malleolus; therefore, the results of this study advocate the use of the Bartoníček classification as a reliable tool to guide treatment.

Characteristics and classification of medial malleolar fractures

AIMS

The morphology of medial malleolar fracture is highly variable and difficult to characterize without 3D reconstruction. There is also no universally accepeted classification system. Thus, we aimed to characterize fracture patterns of the medial malleolus and propose a classification scheme based on 3D CT reconstruction.

METHODS

We retrospectively reviewed 537 consecutive cases of ankle fractures involving the medial malleolus treated in our institution. 3D fracture maps were produced by superimposing all the fracture lines onto a standard template. We sliced fracture fragments and the standard template based on selected sagittal and coronal planes to create 2D fracture maps, where angles α and β were measured. Angles α and β were defined as the acute angles formed by the fracture line and the horizontal line on the selected planes.

RESULTS

A total of 121 ankle fractures were included. We revealed several important fracture features, such as a high correlation between posterior collicular fractures and posteromedial fragments. Moreover, we generalized the fracture geometry into three recurrent patterns on the coronal view of 3D maps (transverse, vertical, and irregular) and five recurrent patterns on the lateral view (transverse, oblique, vertical, Y-shaped, and irregular). According to the fracture geometry on the coronal and lateral view of 3D maps, we subsequently categorized medial malleolar fractures into six types based on the recurrent patterns: anterior collicular fracture (27 type I, 22.3%), posterior collicular fracture (12 type II, 9.9%), concurrent fracture of anterior and posterior colliculus (16 type III, 13.2%), and supra-intercollicular groove fracture (66 type IV, 54.5%). Therewere three variants of type IV fractures: transverse (type IVa), vertical (type IVb), and comminuted fracture (type IVc). The angles α and β varied accordingly.

CONCLUSION

Our findings yield insight into the characteristics and recurrent patterns of medial malleolar fractures. The proposed classification system is helpful in understanding injury mechanisms and guiding diagnosis, as well as surgical strategies. Cite this article: Bone Joint J 2021;103-B(5):931-938.

Medial malleolar fractures: current treatment concepts

The medial malleolus, once believed to be the primary stabilizer of the ankle, has been the topic of conflicting clinical and biomechanical data for many decades. Despite the relevant surgical anatomy being understood for almost 40 years, the optimal treatment of medial malleolar fractures remains unclear, whether the injury occurs in isolation or as part of an unstable bi- or trimalleolar fracture configuration. Traditional teaching recommends open reduction and fixation of medial malleolar fractures that are part of an unstable injury. However, there is recent evidence to suggest that nonoperative management of well-reduced fractures may result in equivalent outcomes, but without the morbidity associated with surgery. This review gives an update on the relevant anatomy and classification systems for medial malleolar fractures and an overview of the current literature regarding their management, including surgical approaches and the choice of implants. Cite this article: Bone Joint J 2019;101-B:512-521.

To fix or not to fix: a novel approach to the safe management of unstable open medial malleolar fractures

Displaced medial malleolar fractures, either in isolation or as part of an unstable ankle fracture dislocation, are conventionally treated with internal fixation. We outline the case of a 76-year-old man with diabetes presenting with a grossly deformed open ankle fracture and extruded tibia through a large medial wound. Following irrigation, wound debridement and minimally invasive fibular fixation, the medial fracture reduced anatomically. Contrary to traditional teaching, the medial malleolus was left without fixation. The patient mobilised partially weight-bearing, progressing to both clinical and radiographic union by 3 months. Nine months following an injury, he walks unaided, can squat and drive and has no medial pain or instability with an Olerud-Molander Ankle Score of 80/100, indicating a good outcome. This is the first reported case of such unique management in the literature and highlights the potential to treat open medial malleolar fractures safely without fixation, particularly when concerned about the soft tissue envelope.