Scott E. Sheehan

Traumatic Finger Injuries: What the Orthopedic Surgeon Wants to Know

Traumatic elbow injuries are commonly encountered in the emergency department setting, but their complexity and clinical significance often go unrecognized at the initial evaluation. Initial imaging in patients with elbow trauma should not only help identify major injuries that require immediate intervention but also allow detection of other, often more subtle injuries that may lead to instability or poor functional outcomes if appropriate treatment is delayed. Awareness and detection of these injuries may be improved by a better-developed and more intuitive understanding of the mechanisms that underlie the most common injury patterns. Ideally, such understanding should prompt appropriate early use of advanced imaging techniques. Traumatic elbow injuries should be described in the radiology report within the context of their clinical significance and their implications for management, information that is often best captured by the injury grading and classification systems used by the orthopedic surgery community. This article reviews the relevant anatomy and functional stability of the elbow and discusses common traumatic elbow injury patterns, including elbow dislocations as well as fractures of the distal humerus, radial head and neck, coronoid process, and olecranon. Less commonly encountered injury constellations that are clinically significant are also described. Injury patterns are explained in the context of the responsible force mechanism by using three-dimensional modeling and animation, with emphasis on the functional impact of associated secondary bone and soft-tissue injuries. The utility of cross-sectional imaging modalities such as computed tomography and magnetic resonance imaging in the acute care setting is discussed, and specific imaging guidelines are provided. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.333125176/-/DC1.

Simplified Diagnostic Algorithm for Lauge-Hansen Classification of Ankle Injuries

Ankle injuries occur in a predictable sequence, allowing a logical understanding of their classification once the injury mechanism is recognized. The Lauge-Hansen classification system was developed on the basis of the mechanism of trauma and is useful for guiding treatment. Three radiographic views of the ankle (anteroposterior, mortise, and lateral) are necessary to classify an injury with the Lauge-Hansen system. Two additional criteria are also necessary: the position of the foot at the time of injury and the direction of the deforming force. Because understanding the mechanism of trauma is fundamental to classifying the injury, three-dimensional movies were assembled for each classification, showing the sequence of ligament rupture and bone fractures that occurs with each type of traumatic mechanism. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.322115017/-/DC1.

Traumatic Thoracolumbar Spine Injuries: What the Spine Surgeon Wants to Know

The Thoracolumbar Injury Classification and Severity Score (TLICS) is a scoring and classification system developed by the Spine Trauma Study Group in response to the recognition that previous classification systems have limited prognostic value and generally do not suggest treatment pathways. The TLICS provides a spine injury severity score based on three components: injury morphology, integrity of the posterior ligamentous complex (PLC), and neurologic status of the patient. A numerical score is calculated for each category, with a lower point value assigned to a less severe or less urgent injury and a higher point value assigned to a more severe injury requiring urgent management. The total score helps guide decision making about surgical versus nonsurgical management. The TLICS also emphasizes the importance of magnetic resonance imaging in evaluating PLC injury and acknowledges that the primary driver of surgical intervention is the patients neurologic status. Knowledge of PLC anatomy and its significance is essential in recognizing unstable injuries. Signs of PLC injury at computed tomography include interspinous distance widening, facet joint widening, spinous process fracture, and vertebral subluxation or dislocation. Familiarity with the TLICS will help radiologists who interpret spine trauma imaging studies to effectively communicate findings to spine trauma surgeons. The complete article is available online .

Pelvic Ring Fractures: What the Orthopedic Surgeon Wants to Know

Treating trauma patients with displaced pelvic fractures requires a multidisciplinary approach at a designated trauma center to reduce morbidity and mortality. Immediate recognition of pelvic ring disruption and determination of pelvic stability are critical components in the evaluation of such patients. Stability is achieved by the ability of the osseoligamentous structures of the pelvis to withstand physiologic stresses without abnormal deformation. The supporting pelvic ligaments, including the posterior and anterior sacroiliac, iliolumbar, sacrospinous, and sacrotuberous ligaments, play a crucial role in pelvic stabilization. Radiologists should be familiar with the ligamentous anatomy and biomechanics relevant to understanding pelvic ring disruptions, as well as the Young and Burgess classification system, a systematic approach for interpreting pelvic ring disruptions and assessing stability on the basis of fundamental force vectors that create predictable patterns. This system provides an algorithmic approach to interpreting images and categorizes injuries as anterioposterior (AP) compression, lateral compression, vertical shear, or combined. Opening and closing of the pelvis from rotational forces result in AP compression and lateral compression injuries, respectively, whereas vertical shear injuries result from cephalad displacement of the hemipelvis. AP and lateral compression fractures are divided into types 1, 2, and 3, with increasing degrees of severity. Knowledge of these injury patterns leads to prompt identification and diagnosis of other subtle injuries and associated complications at pelvic radiography and cross-sectional imaging, allowing the orthopedic surgeon to apply corrective forces for prompt pelvic stabilization.

A biomechanical approach to distal radius fractures for the emergency radiologist.

Distal radius fractures are the most common upper extremity fracture and account for approximately one sixth of all fractures treated in US emergency departments. These fractures are associated with significant morbidity and have a major economic impact. Radiographic evaluation of distal radius fractures is frequently performed in the emergency department setting, has a profound impact on initial management, and is essential to assessing the quality and relative success of the initial reduction. While the most appropriate definitive management of distal radius fractures remains controversial, overarching treatment principles reflect distal radius injury mechanisms and biomechanics. An intuitive understanding of the biomechanics of the distal radius and of common mechanisms of injury informs and improves the emergency radiologist’s ability to identify key imaging findings with important management implications and to communicate the critical information that emergency physicians and orthopedic surgeons need to best manage distal radius fractures.

Sports and the Growing Musculoskeletal System: Sports Imaging Series

Increased youth participation in sports has resulted in increased injury tolls due to shifts toward participation in competitive sports at earlier ages, increased training intensity and competition schedules, as well as specialization into one sport. The physiology of the growing musculoskeletal system makes the growing athlete particularly vulnerable to specific types of injuries. Radiologists must understand the differences between pediatric and adult athletes to recognize the particular injuries to which these young athletes are prone. Imaging and pertinent clinical details of major representative acute and overuse injuries characteristic to pediatric athletes will be discussed.

A Biomechanical Approach to Interpreting Magnetic Resonance Imaging of Knee Injuries

This article discusses common injury mechanisms and the subsequent constellation of magnetic resonance (MR) imaging findings in the knee following trauma in the context of instability, as distinguished by the degree of knee flexion and tibial rotation at the time of initial injury, in addition to the direction and magnitude of the responsible force vectors. Using 3-dimensional imaging, common injury mechanisms are illustrated and correlated with MR imaging findings of the resulting osteochondral, ligamentous, meniscal, and musculotendinous lesions. The most common classification and grading systems for these individual lesions and their subsequent treatment implications are discussed.

Distal radius fracture

The case shown is that of a closed extraarticular bending fracture of the distal radius (Colles’ fracture), with a few interesting twists. By history, we are told that the patient is a guitarist, which gives him a lower tolerance for loss of range of motion of the wrist. Additionally, on the radiographs we see a comminuted dorsal cortex, a marginal fracture of the sigmoid notch, as well as a volar cortical fragment (Fig. 1 and 2). Although the patient is “neurologically intact” by the history, the displaced volar fragment often becomes a future problem, as it can tether or abrade both the flexor tendons and the median nerve. This volar fragment is described as part of Melone’s type III fracture, in which open reduction or excision of the fragment is recommended (4). Displacement and angulatory corrections can often be achieved by closed reduction and cast immobilization. In this particular case, the patient is starting out shortened, with both dorsal and volar comminution, as well as with the volar spike that normally does not reduce by closed methods. Even if length is achieved with the reduction, immobilization in a cast will not likely preserve it. These factors make successful nonoperative treatment unlikely. Given that operative treatment is the appropriate choice, we are given the option of three possible methods: open reduction and internal fixation (ORIF), bridging external fixation from the radius to the second metacarpal with an external fixator supplemented by K-wires across the fracture site, and the relatively recent development of nonbridging external fixation of the radius alone. The remainder of this discussion will focus on why ORIF with a dorsal or volar buttress plate will give the most predictable result for this patient. First, the volar spike should be reduced by open techniques via a volar incision, no matter which method of fixation is chosen. This will give the best chance at avoiding late complications involving the flexor tendons and/or the median nerve, which may be asymptomatic now, but can become symptomatic when he actually starts using his hand and moving his wrist and fingers. For reduction and fixation of this fracture, we need to translate the distal fragment volarly, reestablish volar tilt and radial height, correct malrotation of the distal radius (this can be seen on the prereduction films by the different appearances of the sigmoid notch on either side of the fracture line), and finally, reestablish a dorsal buttress to maintain the reduction. Whereas all of these goals can be met by any of the proposed fixation methods, they are most directly and most reliably achieved by ORIF using a plate. Given that the patient is a guitarist, achieving and preserving early range of motion of the wrist would be especially to his advantage. Either plate fixation or nonbridging external fixation would allow immediate or near-immediate range of motion of the wrist, whereas a bridging external fixator would keep the wrist immobile for at least six weeks, increasing the difficulty of postinjury rehabilitation. To best preserve painless pronation and supination, an accurate reduction of the fracture with correction of the radial malrotation is important. Although this reduction Journal of Orthopaedic Trauma Vol. 16, No. 8, pp. 608–611