• the axial skeleton, consisting of the skull, vertebral column, ribs and sternum – supports and protects vital organs

• the appendicular skeleton, consisting of the shoulder girdle, pelvic girdle and limbs – provides shape and facilitates movement.

• organic matrix of collagen – creates tensile strength

• mineral matrix of calcium and phosphate – creates rigidity and strength

• bone cells, including osteoblasts, osteoclasts, osteocytes and fibroblasts.

Bone cells

Osteoblasts are present on all bone surfaces and form a uniform layer. Their purpose is the synthesis and secretion of collagen and protein, and they promote calcification during rapid phases of this process, e.g., fracture repair. Osteoblasts create the trabeculae of cancellous bone.

Osteocytes form from osteoblasts trapped in matrix. The exact function of these cells is not known, but they appear to act as a pump, controlling calcium release in response to hormones.

Osteoclasts are found near the bone surface. They destroy dead bone and are responsible for reabsorption of bone. They are very mobile and are found in great numbers where bone is undergoing erosion. Their activity is controlled by a number of hormones including parathyroid and thyroxin.

Joints

Joints are the area of contact between bone and bone, or bone and cartilage. They are classified by the type of movement they permit.

Fibrous joints permit no movement at all, e.g., skull joints. Fibrous connective tissue merges into the periosteum of each bone.

Cartilaginous joints permit limited movement because of flexible cartilage between bones. The symphyses have cartilage pads, or discs, between bones, e.g., symphysis pubis or intervertebral joints. Complex ligament arrangements stabilize these cartilage pads to limit movement and facilitate recoil. Synchondroses are cartilage joints that ossify into bone in adulthood preventing movement, e.g., epiphysis of long bone.

Synovial joints form most of the body’s joints. They are further classified by the type and range of movement they allow (see Table 6.1). All synovial joints have a number of similar structured features. They are enclosed in a capsule that is lined with a synovial membrane, which secretes synovial fluid. Bone ends are not in direct contact and are covered by hyaline cartilage. The fibrous capsule is held in place by a number of ligaments.

Muscular system

Muscle tissue is formed to convert chemical energy into mechanical contraction, creating movement. Movements are generated both at joints and in soft tissue. Muscles also assist in maintaining body posture and muscular activity is associated with maintaining body heat.

Muscles are made up of bundles of fibres (fasciculi). The length of these fibres relates to the range of movement the muscle performs; that is, the longer the fibre, the greater is the range of movement. The number of fibres relates to the strength of the muscle. Muscles are attached to the periosteum by tendons. There are two points of attachment, the origin of which remains fixed during contraction while the insertion moves. Skeletal muscles have a rich blood supply which increases dramatically during exercise.

Tendons

Tendons are made up of fibrous connective tissue carrying parallel bundles of collagen fibres. This gives greater flexibility but prevents stretching when under pressure, such as in muscle contraction. They act like a spring, allowing the transition of movement from muscle to bone. Tendons have a sparse blood supply that inhibits healing if damaged.

Ligaments

Ligaments are made up of bundles of collagen that are not designed to stretch. They are attached to bone and are responsible for maintaining joint stability. Undue force may tear some fibres, resulting in them being painful, swollen and in severe cases can result in unstable joints.

Anatomy and physiology

The pelvis is designed to provide structure, strength for weight-bearing and protection of internal organs. It houses the rectum, bladder and, in women, the reproductive organs. The pelvis forms a ring, comprising the sacrum and two innominate bones, each made up of an ilium, pubic bone and ischium (Fig. 6.3).

These bones are supported by strong ligaments at the sacroiliac joint and a cartilaginous joint at the symphysis pubis. In children the innominate bones are supported by cartilage until they fuse around 16–18 years of age. The pelvis has a rich blood supply from the internal and external iliac arteries. The stability of the pelvic ring is dependent on the strong posterior sacroiliac, sacrotuberous and sacrospinous ligaments. Disruption of the pelvic ring can result in significant trauma to the neurovascular and soft tissue structures it protects.

Mechanism of injury

Major trauma to the pelvic girdle is relatively uncommon and accounts for approximately 3–6 % of all skeletal injuries and 20 % of polytrauma cases (Smith 2005); however, the mortality associated with major pelvic fractures may reach 57 % where shock is present on the patient’s arrival (Starr et al. 2002). Most pelvic fractures are caused by motorcycle accidents, accidents involving pedestrians, direct crush injuries, or falls from a height (American College of Surgeons 2008). Falls are also the second highest cause of unintentional death after motor vehicles (Middleton 2011).

Fracture patterns

In adults, isolated pelvic fractures rarely occur. This is because of the strength and ligamentous stretch of the pelvic ring. If significant force is applied, two or more breaks in the pelvic ring are likely to occur. The pelvis has predictable areas of strength and weakness, and therefore, in adults, potential patterns of fractures are easy to predict. In children, the increased elasticity of the pelvis prior to fusion of the innominate bones makes isolated fractures far more likely.

Lateral compression (LC) fractures (graded I, II, III) are caused by a side impact, usually to motorcyclists or pedestrians in collision with vehicles. A compression fracture of the pubic bone or rami is combined with compression fracture on the side of impact (Fig. 6.4A). With greater force of impact, the iliac wing on the side of the impact will also break; this is a grade II injury (Fig. 6.4B). A grade III injury involves an additional fracture on the opposite side to the impact (Fig. 6.4C).

Anteroposterior compression (APC) fractures (graded I, II, III) are caused by direct pressure or crushing and result in the pelvis opening outwards from wings rather like a book. The result is the fracturing of the pubis or rami together with sacroiliac distribution. In grade I injuries, the symphysis is separated by less than 2 cm (Fig. 6.5A); in grade II injuries the sacrospinous and sacrotuberous ligaments rupture (Fig. 6.5B); and in grade III injuries the iliolumbar ligament can rupture (Fig. 6.5C). This type of pelvic fracture has double the mortality rate of the lateral compression injuries.

Vertical shearing force fractures result from falls or from knees hitting a car dashboard with great speed. The pattern of injury is similar to anteroposterior compression, but with vertical displacement (Fig. 6.6). With combined mechanical forces, such as being run over by a motor vehicle, a combination of the above fracture patterns may occur simultaneously.

Patterns of single fracture injury to the pelvis include:

Assessment of pelvic ring injury

Fractures involving the pelvic ring carry potentially life-threatening complications if not rapidly identified and treated. Because of the force exerted to cause such fractures, attendant injury to underlying organs and haemorrhage is common and associated with high morbidity and mortality rates. Injuries can include among others: neurological, 26 %; rectal/gastrointestinal tract, 7 %; renal, 7 %; and bladder, 10 % (Scalea & Burgess 2004); urethral, up to 24 % (Ingram et al. 2008); ureteral, 7 % (penetrating trauma) to 18 % (blunt trauma) (Lynch et al. 2005) as well as genitalia; haematuria and haemodynamic instability due to hypovolaemic shock (Routt et al. 2002).

Mechanisms of injury should give some clues as to a potential pelvic fracture. The assessing nurse should carry out a primary assessment following the ABCDE approach laid out in Advanced Trauma Life Support (ATLS) guidelines (American College of Surgeons 2008). A patient with a pelvic ring fracture will have severe pelvic pain and progressive flank, perianal or scrotal swelling and bruising. Disruption of the pelvic ring can also be identified by differences in leg length and external rotation of a leg without an associated limb fracture.

Mechanical instability of the pelvis can be tested by manual manipulation or compression of the pelvis. This should be carried out only once by an experienced clinician and only when X-rays have excluded unstable pelvic fractures. It is a very painful procedure for the patient and undue force carries the risk of exacerbating haemorrhage. When the clinician manipulates the pelvis, pressure should be applied gently to the iliac crest. If the pelvis has rotated, the clinician will be able to close the ring by gently pushing the iliac crests together. Most patients with a pelvic ring fracture will have moderate to severe hypotension.

Assessment should also include examination of the groin, perineal area and genitalia. Femoral pulses should be checked on both sides. Absent pulses are indicative of damage to the external iliac artery and emergency surgery is required to preserve the limb of the affected side. Decreased pulse pressure should be closely monitored, as it may be indicative of a worsening systemic condition or damage to the iliac artery. The perineum should be inspected for laceration and bleeding. Prophylactic antibiotics should be prescribed for wounds because of the high infection risk from faecal flora (Ruiz 1995).

In men, the testicles should be examined as a swollen testicle is indicative of testicular rupture requiring surgical decompression. The penis should be examined for blood at the meatus, suggestive of urethral damage. In women, the vulva should be examined and the vagina and urethral meatus inspected for blood. In male and female patients where there is no evidence of urethral injury, a urinary catheter should be inserted. If urethral injury is likely then suprapubic catheterization should be considered for bladder decompression. A rectal examination should be performed to test sphincter tone; a reduction in tone is suggestive of a sacral fracture. Frank blood is usually indicative of a rectal tear and surgical intervention is necessary. In men, the position of the prostate should be established as a high, boggy prostate indicates a urethral transection.

Management of pelvic ring fractures

Pelvic fracture can be a life-threatening injury often accompanied by significant haemorrhage and injury to the genitourinary system (Hauschild et al. 2008). Arterial injuries occur in 20 % of patients and posterior fractures are more likely than anterior fractures to cause bleeding. Initial management focuses on volume replacement, stabilization of fractures and, therefore, the rate of haemorrhage and pain control. Fluid replacement should follow ATLS guidelines with a rapid infusion of warmed crystalloid fluid, ideally Ringer’s lactate or Hartmann’s solution (American College of Surgeons 2008). Ringer’s solution closely resembles the electrolyte content of plasma and therefore provides transient intravascular expansion followed by interstitial and intracellular replacement. Normal saline can be used, but large amounts are not recommended because it can induce hypercholaemic acidosis. After an initial 2 L, or 20 mL/kg in children, blood or colloid solutions should be commenced. The patient’s haemodynamic condition should be continuously monitored during this period.

Haemorrhage control relies on fracture stabilization. Early external fixation provides definitive haemorrhage control. As an interim measure, longitudinal skin traction can be used (American College of Surgeons 2008). The use of a pneumatic anti-shock garment (PASG) also known as military anti-shock trousers (MAST) serves a dual purpose of haemorrhage and pain control. It provides mechanical stabilization of the fractures and external counter-pressure. When used, circulation to extremities should be regularly checked as compartment syndrome is a known risk. Decompression should take place in a controlled environment, at a pace that does not exacerbate haemodynamic instability, generally in the operating theatre. The use of PASG in no longer emphasized in ATLS as Dickinson & Roberts (2004) found that there was no benefit from their use, while Mattox et al. (1989) demonstrated PASG increased morbidity and mortality. Pain control is initiated by fracture immobilization with intravenous opiates; inhaled analgesia, such as entonox in the conscious patient may be used where not contraindicated by other potential injuries.

Uncomplicated, isolated pelvic fractures not involving the pelvic ring should be assessed in a similar manner. The management of these injuries is usually conservative. Patients usually require hospital admission for initial bed rest, pain control and rehabilitation support. Most of these fracture injuries have an uncomplicated recovery pattern. Acetabular fractures, however, have a high morbidity rate. They are caused by extreme force, commonly road traffic accidents (RTAs), where the knees hit the dashboard at speed. Long-term prognosis is improved by surgical intervention (Snyder 2002).

Anatomy and physiology

The femoral head and neck lie within the joint capsule of the hip joint. The head of the femur moves within the acetabulum. This is supported by three ligaments: iliofemoral, ischiofemoral and pubofemoral. Blood supply to the head of the femur is largely from the profunda femoris artery, which has circumflex branches around the neck of femur, off which smaller branches supply the head. This pattern of blood supply is particularly vulnerable to disruption from impacted fractures, hence the high risk of vascular necrosis with neck of femur fractures. The periosteum is very thin or non-existent around the neck of femur, therefore making it very susceptible to fractures. This susceptibility increases with age, particularly for women where osteoporosis has further weakened bone strength.

Classification of fractures

Assessment of patients with hip injury

These patients are usually elderly, predominantly women, and commonly attend the ED following a fall. The average age of a person with a hip fracture is 84 years for men and 83 years for women; 76 % of fractures occur in women. Mortality is high; about 10 % of people with a hip fracture die within one month of injury and one-third within 12 months (National Clinical Guideline Centre 2011).

The patient usually complains of groin pain and pain through the thigh to the knee. Pain is worsened by any movement and the majority of patients will have been unable to weight-bear since injury. In most NOF and intertrochanteric fractures, the injured limb will be externally rotated and is shortened if displacement exists at the fracture site. Neurovascular integrity should be checked distally to the fracture, although damage of this type is extremely uncommon. The patient’s haemodynamic status should be regularly observed, particularly with intertrochanteric fractures where blood loss from surrounding tissues is higher than NOF fractures. The patient’s general health should be discussed and pre-existing medical conditions and medication established. It is also necessary to establish the cause of the fall to rule out medical reasons. The patient’s hydration and nutritional status should be assessed, as should skin integrity and risk level for pressure sores (Lisk et al. 2011).

Initial management

In most instances, these fractures can be broadly diagnosed clinically. X-rays provide supplementary information necessary for ongoing management. As a result, patients with clinically diagnosed fractures should receive appropriate analgesia, such as morphine sulphate, prior to X-ray. Hydration at an early stage reduces mortality, and therefore intravenous fluids should be commenced, particularly for patients with intertrochanteric fractures where blood loss is greater. Regular observations should be undertaken to ensure haemodynamic stability is maintained, and to ensure the patient is neither dehydrated nor becomes overloaded by fluid replacements. Early oxygen therapy has been demonstrated to be beneficial as hypoxaemia is evident in elderly patients with a fractured NOF. Most hospitals now have fast-track policies to get patients into a ward bed and off hard emergency trolleys (Audit Commission 2000). If tissue viability is to be maintained, this together with regular pressure area care is vital (Wickham 1997). If the patient’s general condition prohibits internal repair of the fracture, skin traction is advised at the earliest opportunity.

Hip dislocation

The majority of hip dislocations occur in people with total hip replacements or femoral head replacements. Hip dislocations in patients who have not had previous hip surgery are uncommon and demand a great deal of force. Posterior dislocation is commonly caused by high-impact RTAs where the patient’s knee hits the dashboard and account for about 90 % of non-prosthetic dislocations. The patient will present in severe pain, with an internally rotated, flexed leg. Neurological examination is important, particularly in those with marked internal rotation, as the dislocation may compress the sciatic nerve and its branches, resulting in deficits especially in the perineal nerve region. Anterior dislocation is much less frequent and results from a fall from a height where the patient lands on an extended leg. This type of injury can be confused with a fractured NOF in elderly patients, and therefore careful history-taking and limb assessment are vital.

In both anterior and posterior dislocations, early limb relocation is essential. Closed reduction should be performed, provided associated fractures of the femoral head have been excluded. Management priorities in ED involve pain relief, X-ray and relocation of the hip joint under sedation. Once the hip is relocated, the patient should be admitted for traction. If relocation attempts are unsuccessful with conscious sedation in the ED, then urgent transfer to theatre for closed or open reduction under general anaesthetic is appropriate.

Anatomy and physiology

Limbs form part of the appendicular skeleton and are vital for movement. Both arms and legs comprise long bones, with complex joints and bone systems in the hands and feet. Limb injuries treated in the ED fall into two categories: fractures and soft tissue injury.

Classification of fractures

A break or fracture of the bone occurs when it is no longer able to absorb the mechanical energy placed on it. This usually results from trauma (Bickley & Szilagyi 2008). Fractures are classified into the following groups (Fig. 6.9):

Fracture healing follows a specific pattern. It has three main phases: inflammatory, reparative and remodelling.

The inflammatory phase lasts approximately 72 hours. Initially a homeostatic response to the physiological damage to bone, tissue and blood vessels occurs. A clot is formed in which the fibrin networks collect debris, blood and marrow cells. Capillary network increases over 24 hours and neutrophils invade the area. In the following 48 hours, phagocytosis takes place. In the reparative stage chondroblasts and osteoblasts proliferate. The chondroblasts unite fracture ends in a fibrous tissue called callus which begins to calcify after 14 days. During this phase osteoblasts create the trabeculae of cancellous bone while osteoclasts destroy dead bone. Remodelling takes several months: osteoblasts and osteoclasts restore bone shape, replacing cancellous with compact bone (Fig. 6.10).

Assessment of limb injury

Following ATLS principles, assessment of extremity injury should take place after only the primary survey is completed and more serious injuries are dealt with. The assessment has three stages:

Assessment should follow a set pattern regardless of how severe or trivial an injury may appear. The assessing nurse should establish the history, perform an examination and, if appropriate, refer the patient for X-ray. When assessing the history, the nurse should establish a number of factors (Box 6.1). Mechanism of injury should include what happened, the direction and magnitude of force, and how long the patient was exposed to the force. When determining symptoms, the nurse should establish pain, loss of function and perceived swelling. The nurse should also enquire about the duration of symptoms and whether they are worsening or improving. Past history should include pre-existing injuries to that limb, medical conditions that affect the musculoskeletal system or bone density, and factors which would influence recovery.

Examination

Examination should follow a specific pattern, starting from the joint above, moving through the site of the injury, and finally checking neurovascular function distal to the injury. Principles of examination are shown in Box 6.2. Examination starts from the joint above the injury site to assess both function and limits of injury and to gain the patient’s cooperation and confidence. It should be systematic and considering of both the bony and soft tissue structures involved. The examination should also include assessment of pain, and factors influencing it, such as movement, pressure and guarding (Bickley & Szilagyi 2009).

If a patient presents with a mechanism of injury or the clinical examination is suggestive of a fracture then X-ray should be requested. X-rays should not, however, be performed for purely medico-legal reasons (Ward 1999).

Assessment

Fractures of the femur fall into three anatomical categories: proximal, mid-shaft and distal. Examination findings are shown in Box 6.3. The patient should be carefully assessed for signs of hypovolaemic shock as blood loss from a closed shaft of femur fracture averages 1200 mL (Cadogan 2004). Although isolated femoral fractures rarely cause significant shock, fractures occurring with other traumatic injury do contribute to significant hypovolaemia. Observation should therefore be vigilant and X-ray will confirm diagnosis. Severe muscle spasms cause significant pain following femoral fracture and also cause the limb to shorten. Crepitus occurs over the fracture site as bone pieces move (O’Steen 2003).

Management priorities

Management priorities in the ED are twofold: preventing secondary damage and pain control. Preventing secondary damage includes managing blood loss by initiating intravenous fluid replacement. Reduction in blood loss and significant pain reduction can be achieved by correct application of an appropriate traction splint, such as a pneumatic Donway traction splint or a traditional Thomas half-ring splint or its modified version Hare traction splint may be used. These stabilize the fracture until definitive repair can take place. In doing this, the extent of the trauma to surrounding soft tissue is minimized. Pain is reduced because bone ends are immobilized. Distal and proximal pulses, capillary refill and sensation should be rechecked after splint application. If the fracture is open, broad-spectrum antibiotics should be given and the patient’s tetanus status checked. The wound should be covered with a damp dressing; care should be taken to avoid wound maceration if a delay to surgery is possible. Povidone-iodine soaks are commonly used because of the devastating effects of infection (see also Chapter 24). Intravenous analgesia should also be given. Fractured femurs take about 8–16 weeks to heal in an adult and 6–12 weeks in a child. Definitive treatment is usually internal fixation for an adult, which means they can usually be walking within two weeks post-surgery. Surgery is not recommended for children because of growth and speed of repair; therefore traction is recommended for older children, and plastering with hip spica for toddlers and small children.

Supracondylar fractures of the femur are assessed in the same way as shaft fractures. The mechanisms of injury are similar, with pain usually localized to the knee. Fractures involving the femoral condyles usually involve the knee joint and there may be associated knee joint injuries, particularly osteochondral fractures of the patella (Rowley & Dent 1997). These fractures do not cause the same extent of blood loss as shaft fractures and are repaired by either long leg casting or surgery.

Patellar fractures and dislocations

Patellar fractures occur following a direct blow or fall onto the knee. Indirect twisting injury can also result in a fracture as the patella is ripped apart by the quadriceps muscles. The patient presents with pain, swelling and a knee effusion. As a result, range of movement is restricted, particularly full extension. Usually, patellar fractures can be repaired by long leg cylindrical casting for 4–6 weeks. Surgical intervention is necessary for open fractures, those fractures where fragmentation of the patella leaves gaps greater than 4 mm and longitudinal fractures.

Patellar dislocation results from a direct blow to the medial aspect of the knee, common in football or similar contact sports. The knee locks and remains in a flexed position. On examination, obvious lateral deformity is present with medial tenderness and pain on attempted movement. Acute swelling between 2 and 12 hours of injury is likely to indicate haemarthrosis (Rourke 2003, Adams 2004). Treatment seeks to relocate the patella. This is usually straightforward and achieved by extension of the knee. It is painful because of muscle spasm and therefore analgesia and muscle relaxants should be used. A supportive long leg bandage should then be applied, or a long leg cast.

Tibial plateau fractures

Tibial plateau injury commonly occurs from pedestrian/car accidents, usually at lower speeds where the car bumper hits the standing pedestrian. Fractures also occur as a result of a fall from a height, causing compression of the plateau, or they may occur in elderly patients with osteoporotic bones. Patients usually present with pain and swelling over the fracture site and inability to weight-bear. Swelling varies considerably, with haemarthrosis sometimes present. Diagnosis of tibial plateau fractures is usually by X-ray and is classified using the Schatzker classification system (Schatzker et al. 1979) which records six levels of injury:

Choice of treatment is dictated by the classification of the injury, displacement of fragments, and the condition of skin, tissue and muscles. Conservative treatment includes long leg plaster casting, traction and functional cast bracing and is reserved for classes I–IV where surgery is not otherwise indicated. Internal fixation is more common because of the morbidity risk of prolonged immobilization, particularly in older patients (Harris & Haller 1995).

Tibial shaft fractures

Mechanisms of injury are varied. The tibia has little muscular protection, so fractures from direct blows are the commonest long bone fracture. They are also the most common open fracture. As the tibia is vulnerable to torsional injuries, for example in sporting injuries, and force transmitted through the feet is high, the incidence of injury is high (Smith 2005), particularly in children. Similar mechanisms cause tibial and fibular fracture, although much more force is needed to break both bones. Direct trauma tends to cause transverse or comminuted fractures, and indirect trauma causes oblique and spiral fractures. The patient presents with localized pain and is usually unable to weight-bear. Surrounding soft tissue damage varies from a haematoma, causing swelling, to an open wound caused by fracture ends. Treatment for tibial fractures varies: children with greenstick fractures need casting for 6 weeks; in adults, displaced fractures may need internal fixation. ED documentation of the neurovascular status is vital as the risk of compartment syndrome is high. Therefore admission for 24 hours, observation and limb elevation should be considered in very swollen proximal tibial fractures. Pain is managed with intravenous opiates and the lower leg should be plastered as soon as possible. Circumferential casts must never be applied in the acute phase because of the inherent risk of compartment syndrome.

Fibular fractures

Isolated fibular fractures are not common and usually occur in conjunction with tibial fractures. Isolated fibular fractures usually occur as a result of direct trauma to the lateral aspect of the calf. Distal fibular/malleolar fractures occur with excessive rotational forces. They are discussed in more detail under ankle injury below. The patient will complain of pain over the fracture site, with radiation along the length of the fibula on palpation. Because the fibula is not a weight-bearing bone, the patient may be walking with discomfort. Swelling is usually minimal. Depending on the degree of pain, isolated fractures are treated by either plaster cast or compression bandage.

Tibial and fibular fractures

Combined tibial and fibular fractures are fairly common in contact sports, such as football. In injuries where indirect force causes the fracture, the tibia and fibula may be fractured in different places. Commonly, the tibial shaft fractures at the distal third, and because of a twisting mechanism the fibula fractures at the proximal end. This reinforces the need to assess from the joint above to the joint below the injury. If injury is caused by direct force and both bones are fractured at the same level, the leg will appear unstable and flexible at the fracture site. It is important that temporary immobilization occurs as soon as possible, both to reduce pain and to prevent further soft tissue damage. These fractures will need surgical fixation (Gordon et al. 2012).

Ankle fractures

Most ankle injuries seen in the ED are soft-tissue injuries (Eisenhart et al. 2003). Patients with fractures risk significant morbidity if these are not identified and treated early. The ankle is a complex hinge joint made up of three bones: the tibia, fibula and talus, and three collateral ligaments: the lateral, medial and interosseous. These ligaments stabilize the ankle joint; the lateral ligament allows for some inversion of the joint, whereas the medial and interosseous have less stretch (Fig. 6.11). Injury patterns can be classified by the mechanism of injury (Box 6.4 and Fig. 6.12).