Week 18: Trauma Symposium

Perilunate dislocations, as well as perilunate fracture dislocations, are among the most devastating closed wrist injuries. They are often missed on initial evaluation and imaging. Most cases involve dorsal dislocation of the capitate and carpus relative to the lunate, while the lunate remains in near-normal alignment with the radius. Volar perilunate dislocations are possible but rare. An important pitfall, besides missing the injury altogether, is misdiagnosing the injury as a lunate dislocation, which can closely mimic a perilunate dislocation, especially on AP projection. The key to not confusing the two is the lateral projection. On a normal lateral wrist X-ray the capitate, lunate, and distal radius articulate with each other and lie in a straight vertical line, like an apple in a cup sitting on a saucer. The radius (the saucer) holds the lunate (the cup), and this cup contains the capitate (the apple). In a perilunate dislocation, the radiolunate articulation is maintained, but the capitate is not sitting within the distal articular “cup” of the lunate. In a lunate dislocation, on the other hand, the radiolunate articulation is disrupted and the lunate is tipped towards the palm, which is known as the “spilled teacup” sign. Although the diagnosis can be made on plain film, CT plays an important role in assessing for commonly associated occult fractures. A scaphoid fracture is found in approximately 60% of perilunate dislocations; this is then called a trans–scaphoid perilunate dislocation. Perilunate dislocations typically occur in young adults who suffered a high energy trauma, such as a motor vehicle collision, a fall from height, or an injury during a sporting event, resulting in loading of a hyperextended, ulnarly deviated hand, with the angle of this hyperextension determining the extent of injury. Patients may present with obvious marked swelling and deformity, or more subtly, complaining simply of a sprained wrist. A thorough trauma survey with assessment for associated injuries of the head, spine, thorax, and extremities is essential, due to the high energy mechanisms. Orthopedic or hand consultation is required. Like other dislocations, the perilunate dislocation is an emergency and should be reduced as soon as possible. If closed reduction cannot be achieved in the ED, the patient must be taken to the operating room for open reduction. Once the fracture is reduced, definitive treatment can be delayed until the patient’s condition allows additional intervention. Despite early and accurate treatment, stiffness, weakness, and degenerative osteoarthritis commonly occur in the long term. Latent carpal instability is one of the most feared complications and is especially difficult to prevent.

Bonus: what is the most feared complication of perilunate dislocation?  => Median nerve palsy

The coronal reconstruction from a cervical spine CT scan pictured above reveals a type III fracture of the second cervical vertebra. There are three common varieties of fracture of the second cervical vertebra involving the dens, or odontoid process, which articulates with the ring of the first cervical vertebra and which are most common seen in the elderly. The characteristic appearance of the fracture which involves the body of the second cervical vertebra is typical for type III fractures. Type II fractures present at the junction of the odontoid process and the vertebral body. Type I fractures involve the tip of the odontoid process.In neurologically intact patients, these fractures are typically initially treated non-operatively with a trial of cervical immobilization in a hard collar.

It is thought that odontoid fractures are more common in older individuals due to age-related bone loss coupled with the fact that there is disproportionate bone loss in the second cervical vertebra at the base of the odontoid process. Since patients who are 1 to 20 years of age (A), 21 to 40 years of age (B), and 41 to 65 years of age (C) are at lower risk of osteoporosis, they are at less risk for a type III odontoid fracture as compared individuals older than 65 years of age.

Nasal bone fractures account for almost half of all facial fracture injuries. Assaults and sports injuries cause the majority of these injuries. The nose is easily exposed to trauma as it is the most anterior and prominent feature of the face. The frontal sinus is protected by a thick cortical bone and is typically more resistant to fracture than other facial bones. Frontal sinus fractures occur only with high impact traumas such as motor vehicle collisions, assaults with weapons, and industrial accidents. Because of the high energy required to fracture the frontal sinus bone, it is rare to find an isolated fracture without other underlying intracranial pathology. Taking this information into consideration the facial bone LEAST likely to fracture is the frontal sinus bone and the facial bone MOST likely to fracture is the nasal bone.  

Mandible fractures are more common in higher impact injuries such as motor vehicle collisions, sports injuries and interpersonal violence. Most fractures occur at the angle of the mandible or the mandibular condyle. A decent blow to the face during a fight is enough to fracture the mandible making it more likely to break than the frontal bone; hence mandible is least likely and maxilla is most likely (B) is incorrect. Fractures of the maxilla are often the result of high energy blunt force from motor vehicle collisions and falls. Because of its relationship with the orbital bones, nasal cavity and oral cavity, maxilla fractures can be life threatening and disfiguring. Zygomatic fractures typically occur secondary to motor vehicle collisions. Due to the thickness of the bone, isolated zygomatic fractures are uncommon. Taken together this information means that the maxilla is LEAST likely and zygoma is MOST likely (C) is incorrect. Orbital fractures commonly occur in men in the third decade of life secondary to motor vehicle collisions or interpersonal violence. Orbital fractures typically do not occur in isolation as the orbits are set back in the facial structure. The weakest portions of the orbit, and therefore the most frequently fractured, include the orbital floor bones, the maxilla and the lamina papyracea. A direct blow to the eye frequently causes a blow out fracture of the orbital bones; however, this fracturing likely helps to prevent globe rupture. It is easier to fracture the orbital bones (D) than many other facial bones, but nasal fractures are still more likely than orbital fractures.

Important historical information when assessing a patient with a hyphema includes a family or personal history of sickle cell disease or trait, which contributes to a higher risk of complications due to sickled erythrocytes becoming stuck within the trabecular mesh through which fluids drain. This results in increasing intraocular pressure and related microvascular occlusions or retinal and ocular nerve ischemia. These patients require aggressive treatment. Also, a history of other bleeding disorders may indicate difficulty in controlling hemorrhage, as does use of anticoagulants, aspirin, other nonsteroidal anti-inflammatory agents, and alcohol. The time of injury is also important because the chance of rebleeding increases when the development of the hyphema occurred over 24 hours prior to evaluation. Rebleeds tend to occur from two to five days after the injury and put the patient at more risk of corneal staining, development of post-traumatic glaucoma, and delay in resolution of the hyphema.

Helmet use with injury (A) is incorrect. Helmet use may be relevant to other possible injuries, but not specifically to determining a patient’s risk of complications related to the hyphema. Loss of consciousness with injury (B) is incorrect. Loss of consciousness may be an indicator of other potential injuries and their acuities, but it does not directly relate to risk of hyphema complications. Use of eyeglasses or contact lenses at time of injury (D) is also incorrect. While this information may be useful in determining whether other ocular or periorbital injuries are likely, it does not directly relate to risk of complications from the hyphema.

Pediatric injuries involving the physis (growth plate) are characterized using the Salter-Harris classification. This classification describes the fracture line relative to the physis. Injuries of the physis may affect normal bone growth and development, so orthopedic intervention may be necessary depending on the severity of the fracture type. Salter-Harris type I fractures occur when the epiphysis slips off the metaphysis with no associated fracture fragment. Type I injuries rarely affect skeletal development. Salter-Harris type II injuries extend into the metaphysis and are the most common of the Salter-Harris injuries. Salter-Harris type III injuries extend into the epiphysis. Salter-Harris type IV injuries involve the metaphysis, the physis, and the epiphysis. Salter-Harris type V injuries result from axial loading mechanisms and crush the epiphysis. These may be radiographically silent but often impact normal bony development.

Fractures with dislocation (B) may not involve the growth plate and are not part of the Salter-Harris classification. Intra-articular compaction (C) is seen in Salter-Harris type V injuries. Metaphyseal extension (D) is seen in Salter-Harris type II injuries.

The patient presents with hemorrhagic shock and an “open-book” pelvic injury and should immediately have an external pelvic binder placed. Unstable pelvic injuries are typically caused by high-energy impact as seen in motor vehicle collisions. The exact fracture pattern depends on the type of injury. Anteroposterior (AP) compression forces causes disruption near the symphysis pubis and sacroiliac joint opening resulting in the “open-book” pelvic injury. This injury can be diagnosed on an AP pelvic X-ray if the diastasis of the pubic symphysis is >2.5 cm. The high-forces from the injuries cause shearing and tearing of blood vessels leading to hemorrhagic shock. Examination of the pelvis will reveal gross instability. “Rocking” of the pelvis is discouraged as this force may dislodge clots that have formed. Instead, the greater trochanters should be grasped with both hands and gently squeezed together. Any movement with this procedure indicates an unstable pelvic fracture. Once an unstable pelvic fracture is recognized, it should immediately be stabilized with either a properly applied sheet and towel clamps or a commercial pelvic binder. Patients who have immediate stabilization have been found to have lower transfusion requirements. Additionally, the AP injury pattern stands to benefit the most from external stabilization.

Angiographic embolization (A) and CT scan of the abdomen and pelvis (B) may be useful in diagnosis and management of pelvic fractures and hemorrhage into the pelvis but the patient should not be transferred until they are more stable. Diagnostic peritoneal lavage (C) plays a role in differentiating between abdominal and pelvic injuries in unstable patients but should be deferred until after external pelvic stabilization has been applied.

In order to fully understand the different syndromes of injuries to the spinal cord, it is imperative to understand the location of the tracts of the cord. The posterior columns carry tracts responsible for ipsilateral position and vibratory sensation. The lateral spinothalamic tract carries fibers for contralateral pain and temperature. The lateral corticospinal tract is responsible for ipsilateral motor function. Syndromes may be incomplete depending on how much of the cord is affected by the injury. In the anterior spinal cord syndrome, just the posterior columns are preserved and so patients lose all pain and temperature sensation as well as motor function. Most cases of anterior cord syndrome follow aortic surgery, but it has also been reported in the setting of hypotension, infection, vasospasm, or anterior spinal artery ischemia or infarct. In trauma, typically hyperflexion of the cervical spine causes the injury to the spinal cord.

Loss of all motor and sensory function (B) occurs with a complete transection of the spinal cord. Most commonly this occurs after a significant trauma. Isolated motor function loss (A) is not a classic syndrome and would result from a small area of injury on the cord just involving the corticospinal tract. Upper greater than lower motor weakness occurs (D) with a central cord syndrome. Sensory involvement is variable although burning dysesthesias in the upper extremities may occur. Most commonly the syndrome occurs after a fall or motor vehicle accident. Anterior cord syndrome may also be known as ventral cord syndrome.

This patient presents with a myocardial contusion and should have an echocardiogram performed to look for any cardiac damage. Myocardial contusion describes a nebulous condition. It can occur through several mechanisms including a direct blow to the chest and compressive force over a prolonged period of time. Histologically, the disorder has similar findings to those seen after acute myocardial infarction. The majority of contusions heal spontaneously but small pericardial effusions may develop. Delayed rupture after resorption of a hematoma is a feared but rare complication. Patients with myocardial contusion will present after trauma with external signs of trauma and typically have other concomitant thoracic lesions (pulmonary contusion, pneumothorax, hemothorax). Patients will typically have tachycardia (up to 70%). ECG may show dysrhythmia or ST changes but may also be normal. Although myocardial contusion has a very low rate of cardiac complications and it is not effective to admit all patients for workup, in the presence of ECG changes and elevated biomarkers, observation and echocardiography are a reasonable approach. Echocardiogram can be used to diagnose pericardial effusion, thrombi formation, and valvular disruption.

Radial nerve injury is the most common nerve injury seen after humeral shaft fractures. These fractures usually occur from a direct blow to the arm and can be seen in falls and motor vehicle collisions. Patients present with severe pain, arm swelling, and decreased range of motion. The arm can be shortened or rotated in a complete fracture depending on the location of the fracture. A complete neurovascular exam should be performed as with all fractures and dislocations. The radial nerve may be injured during humeral fracture in up to 20% of patients. The injury is usually a neuropraxia and resolves spontaneously in most patients. However, this recovery can take months. Humeral fractures rarely need specific reduction maneuvers for treatment. They should be placed in a sugar tong splint and placed in a sling. Gravity alone is typically successful in fracture reduction.

The anterior cruciate ligament (ACL) is the primary stabilizer of the knee. It resists anterior translation of the tibia on the femur and is the most frequently injured major ligament of the knee. A tear results from deceleration, hyperextension or marked internal rotation of the tibia on the femur. The majority of ACL tears occur during sporting activities such as skiing, football, soccer, and basketball. Clinically, there is usually rapid development of hemarthroses, causing significant swelling. Almost half of individuals report feeling or hearing a pop, which is the most reliable factor. There is usually instability of the knee or a “wobbly” feeling. The Lachman test is the most sensitive test (approximately 98% sensitivity) showing increased anterior tibial displacement and a soft end point. MRI is rarely necessary to make a diagnosis. Rest, ice, crutches, immobilization and NSAIDs are common initial treatment options. Some competitive young patients may choose reconstruction as the best possible chance to return to successful play.