Orthopedic Complications of Trauma

From the musculoskeletal point of view, the major complications of trauma are acute respiratory distress syndrome (Fat embolism syndrome), multisystem organ failure, thromboembolic disease, atelectasis, compartment syndrome, sepsis, and ectopic bone formation.

Pulmonary complications require constant vigilance to prevent serious consequences.

Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome can be a sequela of trauma with subsequent shock. Massive tissue injury releases inflammatory mediators, with subsequent disruption of the microvasculature of the pulmonary system.

Pulmonary edema results, with decreased partial pressures of oxygen and arterial oxygen saturation and increased carbon dioxide levels. The onset is frequently within 24 h after trauma and is revealed by hypoxemia, inflammatory reaction, and a progressive decrease in arterial oxygen saturation if appropriate treatment is not instituted.

Fat Embolism

Fat Embolism Syndrome is a special orthopedic manifestation of ARDS caused by the release of marrow fat into the circulation as may occur following fracture. Pathologic examination of the lungs shows fat droplets, usually diffusely distributed throughout the pulmonary vasculature.

This syndrome may also occur in nonfracture situations, as when the medullary canal of a long bone is pressurized during total knee replacement. Fat embolism syndrome occurs frequently as a sub clinical occurrence that is insufficient to compromise the patient’s pulmonary reserve, but in some cases it can result in severe pulmonary compromise and death.

The clinical diagnosis is confirmed by

• A decrease in arterial Po2
• Increase Pco2
• Infiltrates on chest radiograph
• Presence of petechiae
• Mental confusion in a patient at risk.

Relatively minor injuries can result in this syndrome in patients with limited pulmonary reserve.

Treatment is directed toward minimizing hypoxemia with ventilatory support as needed. Prevention is enhanced by early mobilization of the patient, which often implies early fracture fixation.

Atelectasis

Atelectasis, or localized collapse of alveoli, is a frequent postoperative complication in elective patients and can be prominent in trauma patients because of the required immobilization. Significant hypoxemia can result, and the onset may be relatively rapid.

This may be the source of postoperative fevers in the early recovery phase. Radiographic examination, showing plate-like collapse of areas of the lung, may confirm the diagnosis.

By encouraging coughing and deep breathing, using incentive spirometry, and, in resistant cases, using respiratory therapy, rapid resolution can be expected.

Pulmonary Embolism

Pulmonary embolism is uncommon sooner than 5 days after the onset of immobilization or bed rest. The trauma patient is at risk for pulmonary embolism, and the patient with spinal cord injury perhaps even more so.

Others groups of patients at risk include the elderly, the obese, and those with malignancy.

Oral contraceptive and smoking use may also increase the risk for a young healthy patient.

Patients at high risk for pulmonary embolism are those with deep vein thrombosis in the lower extremities. Clinically significantly pulmonary embolism usually arise large veins proximal to the knee. Prevention deep vein thrombosis in the venous system in this area will reduce the risk.

Definitive diagnosis of deep vein thrombosis is made with venography, duplex ultrasound scanning, impedance plethysmography, or MRI venous sans. Prevention appears to be the best strategy.

Pulmonary embolism is suspected in the orthopedic patient suffering an onset of tachypnea and dyspnea usually more than 5 days after an inciting event. The patient frequently reports chest pain and can often point to the painful area. Hemoptysis may also be present. On physical examination, tachycardia, cyanosis, and pleural friction rub can be noted.

Definitive diagnosis is bet made with pulmonary angiogram. Perfusion ventilation scanning is less invasive and may help determine whether there is a high or low probability of pulmonary embolus.

Spiral CT is becoming useful in diagnosis of pulmonary embolism.

Treatment involves pulmonary support and heparin therapy.

Compartment Syndrome

The team compartment syndrome refers to pathologic developments in a closed space in the body caused by buildup of pressure. Most commonly, such compartments are circumscribed by fascia and incorporate one or more bones.

Pressure rises from edema or bleeding within the compartment, compromising circulation to the contents of the compartment over a period, and can result in necrosis of muscle and damage to nerves.

Compartment syndrome may result from a fracture; a soft-tissue injury; an arterial injury causing ischemia, necrosis, and edema; or from a burn. In an alcohol or drug user, it may be caused by external compression from immobilization that prevents normal postural changes.

The diagnosis of compartment syndrome must be considered in the postoperative or posttrauma patient who has pain out of proportion to that expected from the inciting injury.

As the pain worsens, it can become totally unresponsive to narcotic medication. Epidural narcotics may mask the onset of compartment syndrome in the lower extremity.

Pulses are poor indicators of compartment syndrome as they generally remain intact until late.

Paresthesias occur only when the syndrome is significantly advanced.

Pressure is a key component of compartment syndrome, but the palpitation of a soft compartment does not rule out the diagnosis of compartment syndrome.

Patient with equivocal clinical findings or those at high risk but without a reliable clinical examination ( should have compartmental pressure measurements.

Intracompartmental pressure readings greater than 30-35 mm Hg or intracompartmental pressures win 30 mm Hg of the diastolic blood pressure are indications for fasciotomy.

Positive clinical findings may justify fasciotomy even despite normal pressures. Late fasciotomy may result in muscle damage or possible necrosis, with resulting risk of infection.

Two most common locations for compartment syndromes are the forearm and calf.

Heterotopic Bone Formation

Bone formation after trauma is called heterotropic ossification. Clinically significant heterotopic ossification occurs as a consequence of trauma in perhaps 10 percent of cases and may cause pain or joint motion restriction even to the point of ankylosis.

Trauma patients without head injuries frequently manifest heterotopic ossification on radiograph 1-2 months following trauma.  if the ossification is clinically significant, resection may be indicated when the bone has matured as indicated by radiographs and bone scan. This can take up to 18 months to achieve.

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