Hip arthroplasty

Hip arthroplasty

Anesthesia type	General or spinal ± Regional
Airway	ETT if general
Lines and access	Large bore IV ± Arterial line
Monitors	Standard ± ABP
Primary anesthetic considerations
Preoperative
Intraoperative	Risk for bone cement implantation syndrome (BCIS)
Postoperative	Multimodal analgesia
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Hip arthroplasty (THA) has become one of the most common orthopedic surgical procedures performed since 1960, and it is often one of the most successful. Indications for total hip arthroplasty include osteoarthritis, traumatic arthritis, avascular necrosis, post-proximal fracture arthrosis, and congenital hip dislocation. It is typically performed in patients ages 60 and over, but has been performed in patients of all ages depending on etiology. Older patients tend to require hip arthroplasty for indications like hip fracture and subsequent arthrosis/arthritis, osteoarthritis, while patients of all ages may require hip arthroplasty for indications such as traumatic arthritis and (juvenile) rheumatoid arthritis.

Preoperative management

Patient evaluation

System	Considerations
Neurologic	RA pts: assess for cervical nerve root compression and antlanto-occipital instability. Imaging (lateral film XR) and exam performed as this will alter airway and positioning plans. If regional planned: assess for presence of neurologic conditions (MS, neuropathies, existing nerve injuries) that may be relative contraindications
Cardiovascular	Standard evaluation: more important for older patients with more cardiovascular risk factors. Often will need pharmacologic stress testing as pain and arthritis limit exercise capacity. RA patients, consider increased risk for conduction abnormalities, valvular pathology (AR, valvular fibrosis), pericardial effusion.
Pulmonary	Standard exercise capacity evaluation. In obese patients, evaluate for OSA and potential for resultant pHTN. In RA patients, consider pulmonary fibrosis, effusions, glottic narrowing. For all patients with arthritis, evaluate mouth opening (arthriticTMJ).
Gastrointestinal	Standard evaluation including NPO status
Hematologic	Consider patient anticoagulation status and direct for proper holding of anticoagulation, particularly as regional is used often in these cases. Preoperative hemoglobin should be obtained, as well as type and screen. Consider preoperative blood order (especially if revision).
Renal	Preoperative kidney function (Cr, electrolytes) may be considered (effects on drug clearance; more important in geriatric populations).
Endocrine	Standard evaluation, blood sugar control important for postoperative wound healing
Other	Consider home pain medication regimen; will help guide perioperative analgesic plan.

Labs and studies

• Preoperative labwork, cardiac studies, and imaging will vary amongst patient populations. As in all cases, much of the preoperative studies will be based on individual patient H&P.
• At a minimum, all patients should have a preoperative hemoglobin and type and screen on file prior to case start.
• If procedure is to be a revision, strongly consider ordering preoperative packed red blood cells (PRBCs).

Operating room setup

Standard operating room setup. Airway setup, suction, IV setup, induction medications, emergency drugs, analgesic agents should be prepared and readily accessible.

Tranexamic acid prior to incision and at closure being used in greater frequency for blood loss control

Antibiotics considerations: Beta-lactam (cefazolin) +/- glycopeptide (vancomycin)

Patient preparation and premedication

• Multimodal analgesic technique recommended.
• Preoperative COX-2 inhibitors, gabapentin, and acetaminophen can be considered.
• Enhanced recovery protocols are using PO multimodal medications with greater frequency

Regional and neuraxial techniques

Advantages to neuraxial and regional techniques:

• improved postoperative pain control

• decreased risk of DVT/PE
• decreased intraoperative blood loss.

Neuraxial techniques (particularly spinal anesthesia) have been used with success in patients undergoing THA and especially beneficial in patients who may have a complicated or difficult airway. See discussion on drug choice.

Drug	Conc.	Baricity	Dose	Duration* (min)	Unique Side-Effects
Bupivicaine	0.75%	Hyperbaric	12-16mg	90-120
Bupivicaine	0.5%	Isobaric	12-16mg	90-120
Lidocaine	1-2% 5%	Isobaric; hyperbaric	60-80mg	60-90	TNS (7%)
Mepivicaine	1.5%	Isobaric	50-80mg	100-120	TNS (7%)
Chloroprocaine	2%	Hyperbaric	30-60mg	30-50 (2-level regression) 60-90 (motor) 100-130 (ambulation)	Flu-like symptoms and back ache with epinephrine addition
Ropivacaine	0.75%	Isobaric	15-22.5 mg	120 (motor) 170 (sensory)

Standard consideration of patient factors as they related to absolute/relative contraindications should be undertaken. Additional considerations for post operative mobilization. Some surgical teams and fast tracking joint replacement centers may mobilize patients as early as 2-4 hours postoperatively to help prevent DVT.

Time of procedure should also be considered, as spinal anesthesia has a limited duration of action (typically 2-3 hours, depending on agents used).

Intrathecal long-acting morphine can be considered for postoperative pain control with an understanding that patient selection is important for administration of this medication given the risk for respiratory depression and long duration of action.

Single shot peripheral regional nerve blocks can be used to improve postoperative analgesia, but are not sufficient as a primary anesthetic. Patients must be able to assume the position required to place these blocks. Blocks can help reduce postoperative opiate requirements. Blocks used include:

• femoral
• lumbar plexus
• quadratus lumborum (QL)
• fascia iliaca
• lumbar ESP (Erector spinae plane) block
• PENG Block (Pericapsular Nerve Group Block/Hip Block)

Intraoperative management

Monitoring and access

Standard ASA monitoring. Consider addition of intraoperative EEG monitoring (BIS or similar).

2 large-bore PIV should be obtained. Arterial line for hemodynamic monitoring should be considered for revision procedures, cases with predicted significant blood loss, and for patients with significant cardiopulmonary disease.

Induction and airway management

Induction can be tailored to individual patient comorbidities and acuity. RSI induction is indicated for trauma patients or those without proper fasting per ASA guidelines. For patients with rheumatoid arthritis, special consideration should be given to the airway and potential for cervical (atlanto-occipital) instability. In these cases, videolaryngoscopy or fiberoptic intubation should be considered and utilized.

Induction and intubation on the preoperative bed prior to moving to the operating room table should be considered if possible for patients in whom it would cause significant pain (and resultant physiologic and emotional stress) to execute this move.

Positioning

Surgical Approach	Lateral	Posterior	Anterior/Anterolateral
Position	Lateral decubitus	Lateral decubitus	Supine
Special Equipment	Axillary roll/bean bag	Axillary roll/bean bag	Hana Table Traction boots attachment to Hana table
Positioning Concerns	Brachial plexus injury Neck positioning Check PIV flow	Brachial plexus injury Neck positioning Check PIV flow

If lateral positioning, a beanbag and axillary roll are typically used. Additional blankets/pillows/foam will be needed for under the patients head (to ensure neutral positioning of cervical spine) and to cushion the upper extremities. Reassess padding of pressure points, eye/ear position, monitors, and PIV patency after positioning is complete and prior to case start.

Neuraxial vs General Anesthesia

Observations studies have suggested improved outcomes if neuraxial (particularly spinal) anesthesia is utilized as primary anesthetic over general anesthesia. A recent randomized trial out of NEJM with 1600 patients age >50 compared spinal anesthesia vs general anesthesia (GA) and found:

• Death or inability to walk independently at 60 days: 18.5% in spinal vs 18.0% in GA (RR 1.03, 95%CI .84-1.27, P=.83)
• Death by day 60: 3.9% in spinal vs 4.1% in GA (RR 0.97, 95%CI .59-1.57)
• Inability to walk at day 60: 15.2% in spinal vs 14.4% in GA (RR 1.06, 95%CI .82-1.36)
• New onset delirium: 20.5% in spinal vs 19.7% in GA (RR 1.04, 95%CI .84-1.30)
• Median time to discharge in US: 3 days in spinal vs 3 days in GA (RR 1.06, 95%CI .96-1.16)

In general according to this study, spinal anesthesia was not superior to general anesthesia with respect to 60 day survival and ambulation. Additional postoperative delirium was similar between spinal and GA.

Evidence for TXA

Tranexamic acid (TXA) is an antifibrinolytic agent often used in cardiac and trauma surgery to reduce clot breakdown and subsequent bleeding. TXA has been introduced into procedures with bleeding risk and has been shown to help decrease transfusions and overall blood loss.

Meta analysis of TXA use in total hip arthroplasty reveled strong evidence to reduce blood loss and risk of transfusion. When compared with placebo, IV administration of TXA reduced blood loss by 504 mL and decreased the number of units transfused per patient by 1.43 units. In this meta-analysis, 14 of 15 studies used low doses (10 to 50 mg/kg) of TXA, and the remaining study used a high-dose (150 mg/kg) regimen.

Maintenance and surgical considerations

Standard maintenance. Neuromuscular blockade required if GA, as this facilitates good operating conditions and allows the surgical team to properly test and place the prostethic(s).

Emergence

Standard emergence. PONV prophylaxis dependent on patient risk factors, usually ondansetron 4mg IV.

Postoperative management

Disposition

Typically PACU.

Specialty centers are conducting same-day discharge for pre-screened populations with low-comorbidities and with adequate home support structure

ICU disposition depending on acuity, co-morbidities, and procedure planned (consider this especially with trauma patients or revision cases that have the potential for massive transfusion.

Pain management

Multimodal regimen, consider long-acting opioid agents if no contraindications or risk factors (pulmonary status). Ketamine bolus at induction or low-dose continuous infusion can act as analgesic adjunct. Consider supplementing with single shot peripheral nerve block (fascia iliaca, QL, lumbar plexus, femoral) if no contraindications and patient can tolerate positioning required for block.

Potential complications

• Bone Cement Implantation Syndrome (BCIS)--if pressurized insertion of bone cement (methylmethacrylate) is used ( while hammering of femoral head into acetabulum). Signs can range from mild hypoxia and hypotension to full cardiovascular collapse. Pathophysiology is incompletely understood, but is likely multifactorial in nature consisting of microembolic showering (of air, fat, bone, cement), histamine release/hypersensitivity, complement activation. Treatment is supportive (fluids, vasopressor support, and ACLS in complete cardiovascular collapse), therefore immediate recognition and intervention is important.
• Venous Air Embolism (VAE)
• Venous Fat Embolism
• Blood Loss
• DVT
• Femoral Fracture

Procedure variants

• Depending upon surgical approach. Anterior/anterolateral approaches are performed supine, while lateral or posterior approaches are usually performed in lateral decubitus.

	Unipolar or Bipolar	Revision of THA	Anterior Approach
Unique considerations	unipolar: only femoral head replaced bipolar: femoral and acetabular side are both replaced	blood loss
Position	supine vs lateral decubitus (surgical side up)*	--
Surgical time	2-3hrs	3+ hours
EBL	250-750cc	>1000cc
Postoperative disposition	PACU	PACU vs ICU (depending on transfusion needs or acuity may need to remain intubated)
Pain management	multimodal	multimodal; if infected prosthetic, regional may be avoided depending on extent of infection, overlying infected tissue.
Potential complications	see above	see above	Femoral artery injury during dissection between vastus lateralis and sartorius