A. The rheumatoid neck. Some rheumatoid patients with sufficiently severe joint destruction to necessitate hip or knee replacement surgery may also have significant involvement of the cervical spine. Atlanto-axial or subaxial subluxation should be ruled out on flexion-extension films in patients with neck pain or crepitus on range of motion, radicular symptoms, or arm or leg weakness. These patients are at increased risk for cord compression during intubation or during uncontrolled neck movement while being positioned for surgery. All such lesions should be well-defined preoperatively and discussed with the anesthesiologist and surgeon. These patients should wear a soft cervical collar in the operating room for immobilization and to warn all involved in their care not to manipulate the neck excessively. If possible, epidural or spinal anesthesia should be used.
B. The spondylitic patient. Patients with ankylosing spondylitis may have spinal or peripheral joint involvement and may require surgical intervention in the course of their illness. A variety of problems may arise, primarily as a result of severe spinal involvement. Patients with a rigid or ankylosed cervical spine may present the most challenging cases of endotracheal intubation to anesthesiologists. Fiberoptic techniques can be helpful, even mandatory, in these patients. If the patients are rigid and osteoporotic, there is a risk for spinal fracture and paraplegia with uncontrolled movement. In addition, restrictive lung disease often arises as a consequence of thoracic spinal involvement and increases the potential for postoperative pulmonary complications. Aggressive pulmonary toilet is mandatory in patients with anklyosing spondylitis, irrespective of the type of surgery that they are undergoing. A small percentage of these patients may also have underlying aortic valve disease or conduction abnormalities, which can complicate perioperative management.
C. Fat embolism syndrome. Although generally thought to arise more commonly in young trauma patients, fat embolism syndrome is not uncommon after total joint arthroplasty, particularly in patients undergoing simultaneous bilateral procedures. The time of onset may vary, with hemodynamic instability developing almost immediately (presaged by a rise in pulmonary artery pressure as the prosthesis is cemented) or more insidiously during the first 2 to 3 postoperative days. Postoperatively, patients are moderately to severely hypoxemic, may be hypotensive, and, in the case of the elderly, often become confused.
Hematologic abnormalities such as transient thrombocytopenia are commonly seen. Frank adult respiratory distress syndrome may develop and become life-threatening. Treatment includes the administration of increased concentrations of inspired oxygen (possibly intubation), prevention of pulmonary hypertension by fluid restriction, use of diuretics and venodilators, and prevention of pain. The use of corticosteroid therapy is not recommended. In high-risk circumstances (i.e., patients undergoing bilateral total joint arthroplasty, those with preexisting cardiopulmonary dysfunction), pulmonary artery catheterization for 24 to 48 hours can be helpful to guide therapy. If the pulmonary artery diastolic pressure is maintained at below 20 mm Hg, respiratory insufficiency is usually prevented.
D. Prophylaxis for thromboembolic disease. The prevention of thromboembolic problems after orthopedic surgery has been extensively investigated clinically, and numerous protocols have documented efficacy. Epidural anesthesia has been demonstrated to reduce markedly the rate of proximal deep venous thrombosis (10% vs. 25%) after total hip replacement; the beneficial effect following total knee replacement in comparison with general anesthesia is less certain. Likewise, pneumatic compression stockings, low-dose warfarin (prothrombin time in the range of 14 to 16 seconds), an international normalized ratio 1.5 to 2 times normal, and adjusted-dose heparin have all been reported to prevent venous thrombosis in patients undergoing total joint arthroplasty. Aspirin alone is of questionable efficacy but is useful when combined with other modalities such as pneumatic compression devices or pneumatic compression plus epidural anesthesia in total hip replacement. An alternative approach is to perform venography on the fifth to seventh postoperative day and treat only those patients with evidence of deep venous thrombosis.
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