Anesthesia for Total Hip Arthroplasty

Overview

• THA is an elective joint replacement procedure performed to improve hip function and mobility in patients with degenerative joint disease or chronic arthritis. The surgery commonly involves the use of acrylic cement for prosthesis fixation in middle-aged and older adult populations.
• Anesthetic techniques for THA include general anesthesia, regional anesthesia, or a combination of both. The choice of anesthetic techniques depends on multiple factors, including patient comorbidities, body mass index (BMI), history of bleeding disorders, and recent use of anticoagulant medications.
• In a national study of United States veterans, comparison of postoperative outcomes between patients receiving general versus neuraxial anesthesia demonstrated no significant difference in postoperative mortality.¹

Preoperative Evaluation

• A comprehensive preoperative interview and focused physical exam should be conducted to evaluate a patient’s medical history and comorbidities, with particular attention to
  • Obesity
  • Obstructive sleep apnea
  • Spinal stenosis
  • Osteoarthritis of the spine
  • Rheumatoid arthritis involving the cervical and lumbar spines
  • Coronary artery disease and myocardial infarction
  • Heart failure
  • Cardiac valvular disease
• A comprehensive airway evaluation should also be performed.
• A brief physical exam of the anatomical sites for planned regional anesthesia is warranted.
• Informed consent for the anesthetic plan and peripheral nerve blocks must be obtained.

Laboratory Testing

• Complete blood count
• Basic metabolic panel
• Type and screen given anticipated blood loss

Intraoperative Care

Multimodal Pain Regimen

• The multimodal pain regimen aims to reduce pain in the intraoperative and postoperative period using an opioid-sparing approach. The pain management regimen will vary across institutions, but often involves a combination of the following:
  • Acetaminophen
  • Nonsteroidal anti-inflammatory drugs
  • Ketamine
  • Peripheral nerve blocks
  • Neuraxial anesthesia

Neuraxial Anesthesia Techniques for THA

• Regional anesthesia techniques for THA include spinal anesthesia, epidural anesthesia, and peripheral nerve blocks.
• Spinal anesthesia using bupivacaine in combination with intrathecal opioids (e.g. fentanyl, morphine) provides optimal surgical conditions and effective postoperative analgesia for both total hip and total knee arthroplasty.
• The benefits of neuraxial anesthesia compared with general anesthesia include reduced systemic blood pressure, decreased intraoperative blood loss, shorter operative times, and a lower incidence of DVT.²
• In addition, neuraxial anesthesia provides superior immediate postoperative analgesia and reduces opioid consumption within the first 24 hours following surgery, as measured by oral morphine equivalents.³

Benefits of Spinal Anesthesia

• Lower incidence of DVT and pulmonary embolism
• Reduced blood loss
• Improved immediate postoperative pain control
• Reduced risk of postoperative nausea and vomiting
• Fewer events associated with altered mental status
• Decreased length of hospital stay
• Lower incidence of intensive care unit admissions
• Reduced risk of re-intubation

Benefits of Epidural Anesthesia

• Epidural anesthesia administered as a continuous infusion throughout the case reduces arterial hypotension while maintaining cardiac output, stroke volume, and adequate perfusion to the lower extremities.⁴

Negatives of Regional Anesthesia

• Urinary retention
• Patient’s intolerance of positioning (sitting upright or lateral)
• Technical challenges in performing neuraxial anesthesia in patients with anatomic abnormalities (e.g. scoliosis, arthritic spine changes, higher BMI, prior spine surgery)
• Higher risk for hemodynamic stability, particularly in patients with cardiovascular risk factors or severe hypovolemia
• The possibility of a failed spinal
• Risk of uneven sensory blockade with epidural anesthesia
• Neuraxial procedures and epidural catheter placement may need to be delayed in patients on anticoagulation, per the American Society of Regional Anesthesia and Pain Medicine (ASRA) anticoagulation guidelines

General Anesthesia for THA

• General anesthesia with total intravenous anesthesia or inhalational anesthesia can be used for patients undergoing THA and is the preferred anesthetic technique for patients who have contraindications to neuraxial anesthesia.
• General anesthesia carries a higher incidence of developing DVT due to increased vasodilation and venous pooling in the lower extremities. Inhalational agents in particular are associated with an increased risk of postoperative nausea and vomiting, as well as postoperative delirium and cognitive dysfunction.⁵
• In a study comparing spinal and general anesthesia, there was no statistically significant difference in recovery of ambulation at 60 days after surgery.¹
• General anesthesia with a supraglottic airway may be used if the patient is positioned supine for the anterior surgical approach.

Benefits of General Anesthesia

• Faster recovery time to ambulation in the postanesthesia care unit (PACU).
• Recommended for patients with cardiovascular conditions (e.g., severe aortic stenosis)
• Alternative anesthetic technique for patients with a failed regional anesthetic technique
• Alternative anesthetic technique for patients where there is an absolute or relative contraindication to neuraxial anesthesia, such as:
  • Thrombocytopenia
  • Epidural abscess or localized infection at the intended needle puncture site
  • Anticoagulation
  • Coagulopathy
  • Increased intracranial pressure
  • Demyelinating lesions
  • Preexisting neurological deficits

Negatives of General Anesthesia

• Associated with increased length of operative time (an average of 12-15 minutes longer than patients undergoing regional anesthesia for THA)⁶
• Increased incidence of adverse intraoperative events⁶
• Higher probability of prolonged postoperative ventilator use⁶
• Higher rate of unplanned intubations and difficult airway management
• Higher likelihood of requiring a blood transfusion

Peripheral Nerve Block Techniques for THA

Relevant Anatomy

• The hip joint is innervated by the lumbar and sacral plexuses.
• The obturator and femoral nerves innervate the anterior capsule⁷
• The posterior capsule is innervated by branches arising from the sacral plexus.
• Links for figure 1 and figure 2 

• Several peripheral nerve blocks can offer opioid-sparing multimodal analgesia and pain control for THA. Preferences for peripheral nerve blocks depend on patient comorbidities, patient preference, history of chronic pain, and provider experience.

Lumbar Plexus Block

• Provides postoperative analgesia for lower extremity surgery affecting the femoral head and shaft, but does not provide adequate surgical-grade anesthesia when employed alone.⁷
• May be performed as a single-shot block or with a catheter and continuous infusion
• Preferred in patients undergoing complex THA requiring an extended hospital stay
• ASRA anticoagulation guidelines for neuraxial blocks must be followed due to the risk of hematoma formation within the deep lumbar plexus compartment.⁸
• Complications include:
  • Risk of local anesthesia spread to the epidural space
  • High spinal
  • Local anesthetic systemic toxicity
  • Renal hematoma
• Link for figure 3

Fascia Iliaca Block

• The fascia iliaca block provides a motor and sensory block to the lateral thigh.⁷
• The associated motor blockade may impair ambulation and early mobility in the postoperative period.
• Benefits include reduced opioid consumption 24 hours and 48 hours after block
• For THA, a suprainguinal approach is recommended.
• Link for figure 4

Quadratus Lumborum Block

• A fascial plane block where local anesthetic is injected in the thoracolumbar fascia surrounding the quadratus lumborum muscle
• Provides coverage of the lumbar plexus (T12-L4 nerve roots), iliohypogastric and ilioinguinal nerves, lateral femoral cutaneous, obturator, and femoral nerves.⁷
• Often utilized in patients with high pain scores or a history of high opioid consumption
• However, evidence suggests that the reduction in pain scores is not clinically significant.
• In a multi-center randomized placebo-controlled trial, there was no significant difference in postoperative pain scores and total opioid consumption (as measured with OME) when comparing the anterior quadratus lumborum block vs multimodal pain regimen.⁹
• For patients on anticoagulation, follow the ASRA guidelines for neuraxial anesthesia, given the high-risk of developing a hematoma with deep blocks performed in non-compressible, deep tissue planes.

Complications Associated with Total Hip Arthroplasties

• Several complications can arise during THAs, including bone cement implantation syndrome (BCIS), DVTs, and acute blood loss.
• Polymethylmethacrylate binds the prosthetic implant to the patient’s bone; however, this process can, in rare cases, lead to the embolization of fat, bone marrow, cement or air into venous circulation.¹⁰
• Clinical manifestations of BCIS include hypoxia, hypotension, cardiac arrhythmias, pulmonary hypertension, and decreased cardiac output.¹⁰
• Please see the OA summary on BCIS for more details. Link
• Additionally, patients undergoing hip surgery have an elevated risk of developing DVTs and pulmonary embolism.
• There are several risk factors for developing DVTs, including increased venous stasis, length of surgery exceeding 30 minutes, prolonged postoperative immobilization, and an elevated hypercoagulable state due to inflammatory responses to surgery.¹⁰
• Neuraxial anesthesia can reduce the risk of DVT by sympathectomy-induced increases in lower extremity venous blood flow, systemic anti-inflammatory effects of local anesthetics, decreased platelet reactivity, and by mitigating postoperative increases in factor VIII and von Willebrand factor, and postoperative decreases in antithrombin III and changes in stress hormone release.
• THAs are often associated with significant blood loss. Tranexamic acid, an antifibrinolytic, may be administered intraoperatively to reduce blood loss.¹⁰

Postoperative Considerations

Same-Day Discharge

• At many institutions, THAs are elective procedures with same-day discharge protocols.
• Protocols for discharge on the day of surgery involve a multimodal pain regimen, early postoperative rehabilitation and ambulation, and use of motor-sparing peripheral nerve blocks.⁷
• At several ambulatory surgical centers, patients meeting Phase 1 recovery may proceed directly to Phase II recovery to expedite discharge.
• Physical therapy may begin to work with patients in the PACU to increase surgical mobility.
• The anesthesia plan should prioritize minimizing postoperative nausea and vomiting and avoiding postoperative hypotension.
• In the PACU, patients are monitored for postoperative urinary retention. Patients who received over two liters of fluid while under spinal anesthesia have a 60% increased risk of developing postoperative urinary retention requiring straight catheterization.¹¹