Introduction
Orthopedic diseases are common across all age groups and cause substantial disability and loss of quality of life. The treatment of orthopedic conditions is time-extensive and puts a huge burden on health care costs. The patients may come for the correction of joint and spine deformity, for removal of bone tumor, in addition to the traumatic injuries of bones and joints. The anesthetic management of such patients may be complicated by comorbid illness, large intraoperative blood loss, painful surgeries, and prolonged hospital stay with the risk of infections and deep vein thrombosis (DVT). This chapter is an overview of anesthetic care of common orthopedic diseases, which include the following:
Anesthesia for Arthroplasty
Arthroplasty is a surgical procedure in which a malformed or diseased joint is altered or completely replaced to restore optimal function or relieve pain. Worldwide, the most commonly performed arthroplasty is that of the knee joint and hip joint, followed by shoulder, wrist, ankle, and finger joints. The spectrum of patients ranges from a young, healthy trauma victim to an elderly patient with multiple comorbidities. Therefore, preoperative assessment of patients at risk of mortality and morbidity, preparedness for the intraoperative and postoperative complications, and provision of postoperative care are the main areas of concern for an anesthesiologist.
Preoperative Assessment
In recent times, joint replacement in the active aging population is increasing. The advanced age and cardiopulmonary complications are the most common risk factors for perioperative mortality. Therefore, patients must be evaluated for:
Underlying conditions like rheumatic arthritis, osteoarthritis, and diabetes mellitus pose challenges of a difficult airway, which should be carefully evaluated. Patient’s medications, particularly antihypertensive medication, anticoagulant, steroids, and opioids, should be reviewed, and continuation or discontinuation of these medications should be guideline-adherent.
Technique of Anesthesia
Due to localized surgical sites, regional anesthesia is the preferred choice. Regional anesthesia technique offers several advantages over general anesthesia, including:
Decreased incidence of nausea and vomiting.
Less cardiorespiratory complication.
Improved postoperative analgesia.
Enhanced rehabilitation, early ambulation, and early hospital discharge.
For arthroplasty of lower extremity joints, especially knee and hip joints, central neuraxial blockade provides excellent intraoperative anesthesia and improved outcome. Based on current evidence, the International Consensus on Anaesthesia-Related Outcomes after Surgery (ICAROS) group recommends neuraxial over general anesthesia for hip/knee arthroplasty. Combined spinal-epidural anesthesia (CSEA), along with sedation, is now considered as the technique of choice, where epidural catheter acts as a conduit for postoperative analgesia.
Peripheral nerve blockade, although rarely used as the sole anesthetic, can be used with general anesthesia to reduce the requirement of anesthetic drugs and opioids or for postoperative pain management. The commonly used nerve blocks for knee and hip arthroplasty are listed in Table 32.1.
Perioperative Concerns
A few of the perioperative concerns which should be borne in mind are explained below.
Intraoperative blood loss is a major concern during arthroplasty. Total hip arthroplasty can cause significant blood loss up to 1 to 2 L. Intraoperative and postoperative blood loss is less in regional anesthesia due to reductions in mean arterial pressure and venodilatation. Intraoperative use of tranexamic acid or fibrin spray has also been shown to reduce blood loss. Deliberate, controlled hypotension can also be used as a means of reducing surgical blood loss and need for transfusion. A pneumatic tourniquet can be used to reduce blood loss and provide a bloodless field during surgery.
It is a common occurrence during traumatic orthopedic injuries with fractures of long bones and pelvis being the commonest. The symptomatology usually starts between 24 and 72 hours of insult. The patient presents with dyspnea, chest discomfort, altered mental status, restlessness, hypotension, tachycardia, petechial rash (over conjunctiva, axilla, neck, and upper torso). The dyspnea, petechial rash, and confusion constitute a classical triad of fat embolism syndrome. Gurd and Schonfeld are the most common diagnostic criteria for fat embolism syndrome.
The fat embolism syndrome is hypothesized to occur due to fat emboli-mediated endothelial injury in lungs and brain, leading to acute respiratory distress syndrome (ARDS) and cerebral edema, respectively. The investigations which provide a clue to fat embolism syndrome are:
Retinal examination: Fat globules in retinal vessels.
Urine examination: Fat globules.
Chest X-ray: Diffuse interstitial infiltrates.
High serum lipase (but it does not correlate with disease severity).
The patients with fat embolism syndrome require vigilant monitoring for mental status and respiratory difficulties, and they may need respiratory support with mechanical ventilation in case of respiratory failure. The management aspect includes:
Early stabilization of the fracture.
Mechanical ventilation (noninvasive/invasive) for respiratory failure.
A trial of glucocorticoids can be given (to decrease immune response to fat globules and halt the progression of disease).
3. Bone cement implantation syndrome
Methyl methacrylate cement fixation of the prosthesis can cause bone cement implantation syndrome, which is characterized by:
Implementing “cement curfew” protocol can minimize chances of BCIS and help in timely management if it at all occurs. The patient, surgeon, anesthetist, and other team members of the operation theater are part of this protocol.
The patient must be informed about the risk of bone cement implantation syndrome. The surgeon should be wise in choosing the patient (based on comorbidities and risk of bone cement implantation syndrome) and type of prosthesis for the given patient. He must inform the anesthetist before inserting the prosthesis. The anesthetist must engage in adequate preparation, in order to manage if BCIS occurs. The other team members in the operation theater should be aware and ready to play their roles in case of occurrence of BCIS.
Several mechanisms have been postulated for these events, including embolization of bone marrow debris to the circulation during pressurization of the long bone canal, toxic effects of circulating methyl methacrylate monomer, due to cytokines released during reaming of the femoral canal which promote the formation of microthrombi and subsequent pulmonary vasoconstriction.
For high-risk patients, consider strict hemodynamic monitoring including invasive arterial pressure and central venous pressure (CVP).
At the time of cementation, FiO2 should be increased.
Intravascular fluid and vasopressors for hemodynamic instability.
Advanced cardiac life support protocol in case of cardiac arrest.
4. Postoperative cardiopulmonary complication
The ACC/AHA classify orthopedic surgery as intermediate-risk surgery due to increased risk of perioperative myocardial morbidity and mortality. Multiple medical comorbid conditions, age-related limited functional capacity, surgery-induced systemic inflammatory response syndrome, fluid shifts, and blood loss during surgery and postoperative pain can trigger a stress response, leading to tachycardia, hypertension, and increased oxygen demand which could lead to myocardial ischemia.
Patients at risk of perioperative cardiac complications should be assessed postoperatively for myocardial ischemia. Age-related respiratory changes, embolization of bone marrow debris to the lungs during surgery, obesity, and obstructive sleep apnea can lead to respiratory complications.
The incidence of deep venous thrombosis (DVT) is quite high with arthroplasty surgeries. Anticoagulant prophylaxis or intermittent pneumatic compression should be considered in patients with a high risk of bleeding.
6. Postoperative pain management
Multimodal analgesia is essential for pain relief and minimize side-effects while maintaining rehabilitation and patient satisfaction.
Anesthesia for Orthopedic Tumors
Tumors encountered in orthopedic practice develop either within the bone or soft tissue. Metastatic tumors are more common than primary tumors. There are four most common types of primary bone cancer:
Generally, surgical removal of the tumor is the preferred treatment. Often radiation therapy or systemic chemotherapy is used in combination with surgery (limb salvage surgery, amputation).
Preoperative Assessment
Patients should be assessed for comorbid conditions just like other surgeries. Special consideration is given to the type, size, tumor invasiveness, plan of surgical procedure, and current chemotherapy and radiotherapy treatment.
All possible side effects of chemotherapeutic agents should be investigated preoperatively. Table 32.2 highlights the important chemotherapeutic agents and their side effects.
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