Christine M. Wilson, Mary E. Farrell, Nicole C. Bove, Susan E. Bove Common musculoskeletal injuries include sprains, strains, dislocations, and fractures. Sprains result from a stretching and/or tearing of the ligaments that bind the joint (bone to bone) as the joint is forced beyond its normal range of motion. Strains result from the overstretching or overuse of muscles and/or tendon (muscles to bones). Dislocations occur when a bone is displaced at the joint so that the articulating surfaces of the bones detach. Partial displacements are called subluxations. A fracture is a break in the cortex of bone. Fractures may be classified as closed or open. A closed (simple) fracture has no associated disruption in the continuity of the overlying skin. An open (compound) fracture has an associated disruption through the skin to the environment. Strains and sprains are often cared for in private physician offices, clinics, and athletic training centers or simply at home. This makes statistical tracking of these types of injuries impossible. Although insurance companies’ billed diagnosis codes offer a means of data collection if patients are treated at a medical facility, many of these injuries are managed at home.1 Strains, sprains, and fractures are common musculoskeletal injuries. Strains are minor injuries that result when a muscle is overstretched. No actual muscle damage occurs with a muscle strain. A sprain involves actual injury to the supporting structures of the affected joint and is described in three grades of severity. The degree of damage to these structures depends on the amount of tissue and fiber shearing and tearing that occurs. A grade 1 sprain usually involves minimal injury with stretched fibers or a few microscopic tears of a ligament resulting from overstretching and causes only pain and edema. A grade 2 sprain is an incomplete tear of a ligament and also includes some functional impairment, ecchymosis, and discomfort or pain with weight bearing. A grade 3 sprain is a full or complete tear of the ligament with loss of ligament integrity. Grade 3 sprains of the lower extremities result in severe weakness loss of function produced by the detached muscle.2 Bone injuries can result in fractures, avulsion fractures, stress fractures, and dislocations. A fracture is a break in the bone. An avulsion or osteochondral fracture occurs when the ligament pulls away from the bone, bringing fragments with it, usually after a forceful injury. The pulling or pushing of a bone out of its normal position in the joint results in dislocation, which can be complete or incomplete. Stress fractures are small cracks in bone that initially may not be seen on x-ray examination. Repeated x-ray studies after 2 weeks or more may show new bone formation at the fracture site. The Ottawa Ankle Rules (OARs) were introduced for determining the need for radiographs of the acutely injured ankle or midfoot.3 However there are now data questioning their usefulness.4 Strains cause local pain and, if severe, palpable swelling or muscle spasm. Sprains may demonstrate swelling, discoloration, and pain with movement. Fractures usually manifest with an area of pinpoint pain. There may or may not be associated swelling, discoloration, and decreased range of motion with a fracture. Dislocations involve the joint and often produce a visible deformity. Patients often experience more pain with dislocations than with fractures, as the nerves, tendons, and vessels crossing the joint are disrupted. Injuries that occur as a result of crushing or compression should be evaluated immediately because they can lead to neurovascular compromise and permanent tissue damage. It is difficult if not impossible to exclude a fracture without x-ray studies. In any trauma, it is essential to exclude or to stabilize any life-threatening injuries first. A good musculoskeletal examination includes an in-depth history, which should explore the mechanism of injury with a focus on the physical forces incurred by the patient. Often, this assessment is simplified by asking the patient to use the opposite extremity to reconstruct the exact motion of the affected side during the injury. A good history of the mechanism of injury will also provide vital information about the presence of a compression injury. This will permit accurate diagnosis of these injuries and allow correct treatment and ongoing monitoring. A past medical history of arthritis, birth defects, or past injuries or surgery that resulted in deformity must be elicited. Physical examination includes observations of the patient’s favoring or guarding of the affected area. Pain, swelling, discoloration, deformity, or open wounds should be noted. The joint above and below the injury should also be examined for injury. Circulatory, motor, and sensory function must be assessed. Palpation for joint laxity can be deferred until a fracture is ruled out. In an elbow injury, the arm is usually flexed at the elbow with the palm toward the chest. From this position, the patient should be asked to move only the lower arm away from the body so that the hand is pointing straight ahead. If elbow pain is elicited, this is indicative of a radial head fracture. Wrist fractures are quite common in the older adult who has fallen on an outstretched arm. Colles fractures (extension fracture of the distal end of the radius) and Smith fractures (flexion fracture of the distal end of the radius) are the most commonly seen types. When evaluating fractures in adolescents or children, it is important to recall the classification method developed by Salter-Harris. There are five major types (and more subdivisions) of Salter-Harris fractures, all involving the growth plate of the immature skeleton.5 Ankle fractures with tenderness through the mortise of the ankle can indicate an associated knee fracture. This indirect fracture of the knee is easily missed on the initial examination; therefore care should be taken to palpate the areas of the upper tibia and fibula and the knee. Because of the difficulty in determining the type of musculoskeletal injury based on presenting symptoms alone, radiologic examinations are often ordered. Radiologic examinations help diagnose fractures versus soft tissue injury. A history of trauma followed by immediate signs or symptoms of pain, swelling, discoloration, limited range of motion, or decreased strength is an indication for x-ray studies. Injuries associated with the ability to bear weight or the absence of swelling, however, may still require x-ray evaluation to rule out fracture. Fractures are diagnosed when a break in the bone cortex is visible on two radiographic views. Angulated fractures refer to either open or closed fractures, usually with more than 30 degrees of angulation. A transverse fracture is straight across the bone. Oblique fractures are seen diagonally on x-ray films. Spiral fractures are seen as wrapping around the bone. A greenstick fracture is diagnosed when the bone tears as if a fresh twig were being bent in two. This is commonly seen in children because they have a more porous cortex, which makes the bone more flexible. An impacted fracture occurs when both pieces of the broken bone are crushed into each other. A comminuted fracture is observed when the bone ends shatter with multiple fragments. Stress fractures occur from overuse and continued pounding to the bone, which causes it to fracture. They are often seen in athletes who run on hard surfaces. Impaired healing results from repeated injury and pounding on pavement. In the athlete younger than 15 years, the growth plate is still open, and overuse alone may cause a stress fracture in the elbows, knees, tibias, fibulas, heels, and foot.6 Jones fractures involve a fifth metatarsal stress fracture. The fracture itself is distal to the proximal tuberosity and tends not to heal without prolonged immobilization or internal fixation. Three common clinical presentations require consideration of additional radiographic views. These are injuries to the navicula, patella, and acromioclavicular joint. Although it is possible to miss a navicular fracture with only a wrist series, the addition of an ulnar deviation view allows more complete assessment of this injury. This view is especially important in the presence of snuffbox tenderness. An injured patella may be better assessed with the sunrise view, which will clearly identify joint effusion and patella fracture. X-ray views taken of a tender acromioclavicular joint while the patient is weight bearing will confirm acromioclavicular separation and allow grading. Hip x-ray examination usually requires a frog-leg view. Foot fractures of the talus and calcaneus have been misdiagnosed as ankle sprains. A foot fracture must be carefully considered in the differential diagnosis if the patient reports a twisting injury or severe fall and is walking with an antalgic gait (manner of walking so as to minimize pain in a limb).7 Talar dome fractures at any age may not be visible on x-ray films for 2 to 4 weeks after injury. In an elbow injury, the arm is usually flexed at the elbow with the palm toward the chest. From this position, the patient should be asked to move only the lower arm away from the body so that the hand is pointing straight ahead. If elbow pain is elicited, this is indicative of a radial head fracture. Compression fractures of the vertebra are seen in older adults with osteoporosis (see Chapter 182), patients on chronic steroids, and those with certain metabolic diseases. Presentation of any musculoskeletal injury requires exclusion of sprains, strains, fractures, dislocations, subluxations, and ligamentous or muscle tears. A large muscle rupture may initially be seen as a convex or concave area with decreased range of motion and pain. Once traumatic injury has been excluded, local and systemic causes, such as various forms of arthritis, autoimmune diseases, infection, phlebitis, and tumor, must be considered.
Sprains, Strains, and Fractures
Definition and Epidemiology
Immediate emergency department referral or physician consultation is indicated for any patient with compound fractures or neurovascular compromise of an extremity.
Pathophysiology
Clinical Presentation
Physical Examination
Diagnostics
Other Types of Fractures
Differential Diagnosis
Sprains, Strains, and Fractures
Chapter 187
