Anesthesiology

Anterior Cruciate Ligament Reconstruction

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What the Anesthesiologist Should Know before the Operative Procedure

First decision point

Determine preoperative baseline pain score with movement. Moderate or higher (versus none-mild) preoperative pain with movement predicts higher postoperative pain scores with movement. Anterior cruciate ligament (ACL) tears can accelerate knee arthritis. In these patients, distinguish chronic arthritic pain (likely to benefit more from nerve block analgesia) from the acute episodic pain associated with knee instability. Patients with higher baseline pain scores with movement may be more suitable candidates for continuous perineural catheter when a single-injection block would typically be recommended (see later). With moderately painful orthopedic surgery on an ambulatory basis (i.e., same-day discharge), the primary goal is to minimize the risk of the patient experiencing moderate-to-severe pain at home. The anesthetic and analgesic plans (e.g., perineural analgesia) should be sufficient to minimize oral analgesic requirements to drugs/doses such as acetaminophen (e.g., 650 mg every 6 hours) and oxycodone (5 mg every 6 hours is an appropriate target).

Second decision point

Issues per nerve distribution of surgical trespass are as follows: territories of innervation trespassed surgically: femoral, sciatic; others in unusual circumstances (saphenous, obturator, lateral femoral cutaneous) and duration of anticipated moderate to severe pain (will this pain duration be adequately managed with a single-injection nerve block versus perineural catheter infusion?).

Third decision point

Review surgical plan and derive the corresponding nerve block considerations (i.e., based on graft type) to meet the “less than moderate pain” objective for patients discharged home the same day. Conventional single-bundle allografts (i.e., from cadaver) are typically the least painful, with the smallest surgical incisions. Single-injection femoral nerve block of about 20-hour duration likely sufficient (e.g., bupivacaine 0.25% with epinephrine 2.5 to 5 μg/mL, or other possible off-label perineural analgesic adjuvants such as clonidine and/or buprenorphine). Emerging double-bundle allograft technique (i.e., from cadaver) involves more extensive exposure, dissection, and tunnel-drilling for the passing of grafts. Perineural femoral catheter (e.g., 0.2% ropivacaine with approximately 5 mL/hr infusion with patient-controlled bolus potential) would be considered standard analgesia, while single-injection sciatic block (similar to suggested femoral single-injection block drugs as in the single-bundle allograft above) would be required for sciatic-mediated pain.

Patellar tendon autograft techniques also involve extensive exposure and dissection, as well as osteotomy of patella to prepare the graft. Femoral perineural catheter would be considered standard analgesia. Sciatic nerve distribution may be involved in transmitting pain from deeper within the knee, either related to nearby dissection during harvest or insertion; this osteotomy pain (in addition to tibial drilling) may render the patient as a candidate for a sciatic single-injection nerve block. Hamstring tendon autograft techniques involve the retrieval of the graft from the posterior knee, rendering sciatic distribution pain as ubiquitous (sciatic single-injection block indicated) as well as perineural femoral catheter. Carefully review patient history for possible contraindications to peripheral nerve block. Previous extremity fractures can be associated with latent nerve damage, which may manifest with subsequent trauma and/or nerve block. Issues regarding diabetes and peripheral nerve blocks are addressed later.

Emerging evidence suggests that blocking the femoral nerve distally via the adductor canal block (ACB) rather than the traditional approach to the femoral nerve block may provide additional perioperative benefits following anterior cruciate ligament reconstruction (ACLR). These reports show noninferiority of postoperative pain control for ACB versus femoral nerve block while better maintaining quadriceps muscle strength. Although the long-term benefits must still be studied, ACB seems like a viable alternative to conventional femoral nerve block with the added benefit of preserving quadriceps muscle strength.

1. What is the urgency of the surgery?

What is the risk of delay in order to obtain additional preoperative information?

For elective ACLR surgery, all medical comorbidities should be optimized well in advance of the day of surgery. For this example, we will assume a young healthy athlete who has been ruled out for all medical conditions that may be missed in a routine sports-related history and physical examination.

Emergent: ACLR is elective surgery, not emergent.

Urgent: ACLR is elective surgery, not urgent.

Elective: Although “pre-habilitation” of the lower extremity musculature (e.g., quadriceps femoris muscle) may improve physical therapy outcomes and return-to-sports, this decision is not within the auspices of the anesthesia care team. Any quadriceps dysfunction present preoperatively may theoretically complicate physical therapy outcomes, both dependent on and independent of peripheral nerve block analgesia. For other medical evaluation concerns, see Preoperative Evaluation.

2. Preoperative evaluation

Rarely, the sports medicine patient has interesting medical and social histories that are missed by routine examinations. Although uncommon, some are highlighted here. Medically unstable conditions warranting further evaluation include exercise-induced asthma or any reactive airway condition; chronic inhaled marijuana, cocaine, and/or methamphetamine and subsequent pulmonary dysfunction; obstructive sleep apnea; cardiac dysrhythmia risk from acute cocaine intoxication; cardiomyopathy (hypertrophic, chronic cocaine, alcohol abuse, etc.); mitral valve prolapse or other valvular anomalies, with or without supraventricular tachydysrhythmias; sickle cell trait in African American athletes; and coagulation factor deficiencies such as von Willebrand disease.

Delaying surgery may be indicated if (1) the condition above was previously unknown and an alternative to a "trigger anesthetic" (with respect to the comorbidities listed above) is not readily available and (2), for example, facility does not have equipment or skills to perform a spinal anesthetic or lumbar plexus–sciatic nerve block for a patient with a pulmonary condition listed above and/or active wheezing and/or concurrent upper respiratory tract infection.

3. What are the implications of co-existing disease on perioperative care?

b. Cardiovascular system

Perioperative evaluation

When discussing the following cardiac conditions: cardiac dysrhythmia risk from acute cocaine intoxication; cardiomyopathy (hypertrophic, chronic cocaine, alcohol abuse, etc.); and mitral valve prolapse or other valvular anomalies, with or without supraventricular tachydysrhythmias, there are different evaluation strategies management plans. Of note, outpatient treatment of hypertrophic cardiomyopathy and supraventricular tachydysrhythmias often includes the use of beta blockers, which may cause athletic performance fatigue and may be stopped by the patient as a result of inhibited sports performance. Eliciting a history of beta blocker prescription (and either having taken continuously or discontinued without physician consultation) should prompt detailed evaluation about these underlying cardiac conditions.

Acute cocaine intoxication

This condition may not necessarily manifest as cardiac abnormalities on electrocardiographic tracings, and such tracings are not routinely obtained in advance in otherwise “young and healthy athletes.”

Diagnosis: High index of suspicion based on behavioral or other signs (e.g., hyperhidrosis), and available toxicology screens of blood and/or urine.

Risk mitigation: Detection of acute cocaine use or intoxication is logically followed by case cancellation and referral to appropriate professionals.

Cardiomyopathy

This condition is diagnosed typically with cardiac imaging techniques such as echocardiography, nuclear medicine techniques, combinations of such, and/or other emerging diagnostic technologies.

Diagnosis: History should include specifically asking about syncope during sports as a possible clue regarding hypertrophic cardiomyopathy. Stenosis of the left ventricular (LV) outflow tract below the aortic valve, along with associated concentric LV hypertrophy (with or without abnormalities in ejection fraction, e.g., dependent on Valsalva maneuver) is the classic echocardiographic finding. Cocaine- or alcohol-induced cardiomyopathy is rare in an elite athlete but possible in former athletes and is marked by diffuse LV hypokinesis and reduced ejection fractions.

Risk mitigation: Cardiomyopathy (idiopathic or induced by chronic alcohol or cocaine) is logically managed by achieving an appropriate balance of afterload reduction and peripheral vasoconstriction to maintain adequate cardiac output and mean arterial pressure. Hypertrophic cardiomyopathy similarly managed as above with special attention to maintaining bradycardia (typically with intraoperative beta blockers). Neither general nor spinal anesthesia may be best-available choices in this context; lumbar plexus and sciatic block may best minimize precipitous hemodynamic shifts in this setting, with careful attention to avoiding unwanted bilateral spread of the lumbar plexus block.

Mitral valve prolapse and/or supraventricular dysrhythmias

These are diagnosed-confirmed with echocardiography and 24-hour Holter monitoring, respectively.

Diagnosis: Diagnosis is made per expert interpretation of the aforementioned echocardiographic testing and sustained-duration rhythm monitoring. Certainly, one of these conditions can be mutually exclusive of the other.

Risk mitigation: Avoiding tachycardic triggers (induction-intubation, isobaric bilateral spinal) is useful. Appropriate antibiotic coverage, if needed, in the presence of a valvular abnormality, as indicated by current SCIP guidelines. Immediate availability of “rapid on–rapid off” agents to attenuate episodes of tachycardia (such as esmolol or adenosine) is prudent.

c. Pulmonary

Perioperative evaluation

When discussing the following pulmonary comorbidities—(a) exercise-induced asthma or any reactive airway condition; (b) chronic inhaled marijuana, cocaine, and/or methamphetamine and subsequent pulmonary dysfunction; and (c) obstructive sleep apnea (OSA), there are different evaluation strategies and management plans. Of note, exercise-induced asthma is common among active elite athletes and can pose significant intraoperative risks under general anesthesia (but not typically regional anesthesia). Chronic pulmonary dysfunction from illicit drugs is uncommon in the currently active elite athlete but may be present in former elite athletes. OSA has been reported in elite athletes who are non-obese; OSA can be exceedingly common in former elite athletes in whom muscle mass has transformed to other soft tissue (e.g., American football lineman who is 300 to 350 pounds during active career with coinciding musculature but who does not engage in necessary weight loss lifestyle changes after retirement).

Exercise-induced asthma

Diagnosis is made on the basis of clinical history and pulmonary function tests when symptomatic; condition is typically responsive to inhaled beta-2 agonists during testing.

Risk mitigation is most straightforward by avoiding all airway instrumentation and instead planning for an ipsilateral hyperbaric spinal anesthetic. If forced to instrument the airway, propofol is considered a better airway relaxant than is etomidate or thiopental. The laryngeal mask is generally considered less traumatic than laryngoscopy and intubation. However, the laryngeal mask is not fully protective against airway secretions contacting larynx-trachea-bronchi, leading to potential laryngospasm-bronchospasm, respectively, in a patient predisposed to such. Volatile agent use to attenuate bronchospasm requires high inhaled concentrations, likely worsening immediate postoperative hyperalgesia and postoperative nausea and vomiting. Low-dose intravenous succinylcholine can be useful to “break” laryngospasm, as can intratracheal or transtracheal lidocaine. Likely, the easiest way to avoid airway complications is to avoid airway instrumentation.

Impaired oxygen diffusion from chronic abuse of illicit inhaled drugs

Diagnosis is first by astute suspicion, followed by detailed pulmonary function testing with detailed analysis of arterial blood gases (e.g., carbon monoxide lung diffusion). However, the practicability of this preoperative workup on the day of surgery seems low, and would seem unlikely to change the anesthetic plan. Risk mitigation is most straight-forward by avoiding cardiopulmonary stress related to airway instrumentation, instead planning for an ipsilateral hyperbaric spinal anesthetic.

OSA

Diagnosis and grading are well documented in Task Force Guidelines from the American Society of Anesthesiologists. Men with history of snoring may be more likely to have undiagnosed OSA than are women with snoring. Also useful for diagnosis based on a history of worsening exertional function is an echocardiogram to determine possible pulmonary hypertension. Risk mitigation involves early diagnosis (sleep study) and treatment (airway appliance) long before arrival to the operating room. Using the patient's own airway appliance in the operating room is desired, reinforcing the need for patient-family to bring the device to the surgery center.

Because most patients encountered in clinical reality will be undiagnosed, two approaches can be taken: (1) case cancellation and proper evaluation and management or (2) proceeding with the case assuming the “worst case” scenario for a patient with a “pending diagnosis.” Securing the airway is a concern with the potential for difficult ventilation and/or difficult intubation. This process can be catastrophically complicated by post obstructive pulmonary edema. Although it is possible to perform lumbar plexus and sciatic blocks with little patient sedation and judicious use of subcutaneous and deeper-tissue local anesthetic, coinciding obesity in such patients renders the risk of falling very high (i.e., from lower extremity weakness) if such patients are discharged home the same day. Commonly, the “better part of valor” in extreme cases may lead to a decision to maximizing use of regional anesthetic techniques with minimal sedation, while still planning for hospital admission for both respiratory monitoring and minimizing fall risk.

d. Renal-GI:

There are typically no relevant renal or gastrointestinal comorbidities that are commonly associated with elite, athletic patients undergoing ACLR. The user can refer to other sections addressing these coexisting diseases for more detailed review. Presence of significant gastroesophageal reflux disease (GERD) may be a consideration in airway management if general anesthesia is chosen.

e. Neurologic:

There are typically no relevant neurologic concerns to the athletes undergoing ACLR. Possible comorbidities include history of seizures and medications as such should be continued as prescribed in the peri-operative period. Other neurologic conditions would have to be specifically addressed with the provider prior to operation.

f. Endocrine:

The primary endocrine comorbidity that may present in an elite athlete is diabetes mellitus. Although perioperative blood glucose management is crucial for perioperative safety and outcome (e.g., avoiding nonketotic hyperosmolar coma in a classic “type 2 diabetic” or avoiding diabetic ketoacidosis in a classic “type 1” diabetic), the emphasis here will be placed on perineural safety in the setting of perineural analgesia.

Peripheral nerve block considerations for the sports medicine patient with diabetes mellitus

Assume (for this case) the diabetes is well controlled and euglycemic, either type 1 or type 2. Acknowledge a higher risk of surgical wound infection, with a potential value for reemphasizing the role of spinal anesthesia as being preferable to general anesthesia. Potential value of maximizing the fraction of inspired oxygen in diabetic patients with concerns about microvascular disease may lead to the choice to avoid nitrous oxide if general anesthesia with an airway device is required.

Assume (but cannot prove) there is a higher potential nerve damage risk (in diabetics) from perineural local anesthetics. Also assume that a higher threshold of electrical current is needed to evoke a motor response using nerve stimulation in a diabetic patient (compared with a nondiabetic patient). There is the potential for decremental sensory/motor/proprioceptive function, possibly undetectable by patient, when typical doses of perineural local anesthetics are used. Consider reducing typical concentrations and/or volumes of local anesthetics by, for example, 33% to 50% of doses considered safe for nondiabetic patients. At the possible risk of a catheter-site infection, perineural catheters may be beneficial relative-to-risk to allow analgesic titration with the lowest possible concentrations and volumes.

Regarding the diagnosis of diabetic neuropathy, formal electromyography (EMG), nerve conduction studies, and the neuropathy diagnostic process are not necessarily routine in clinical practice. It is uncommon for an elite athlete to have preoperative EMG baseline testing before elective sports surgery such as ACLR. However, there are no clinical data to inform our practice describing whether diabetics without neuropathy are at greater risk for worsening “subclinical neuropathy” into clinically symptomatic neuropathy after first exposure to perineural local anesthetic.

Risk mitigation is most straightforward by avoiding cardiopulmonary stress related to airway instrumentation, instead planning for an ipsilateral hyperbaric spinal anesthetic. To the extent considered “more beneficial than risky,” the careful use of peripheral nerve blocks and/or catheters at doses/concentrations significantly lower than those used for nondiabetic patients. Perineural adjuvants such as clonidine and buprenorphine in combination may provide perineural analgesia in the absence of local anesthetics; local anesthetics are known peripheral neurotoxins, while there are early reports that clonidine-buprenorphine in clinical doses does not precipitate neurotoxicity. Relegating the patient to a general anesthetic with systemic opioid analgesia may lead to unwanted postoperative nausea and vomiting (PONV), the duration of which runs the significant risk of disrupting glycemic balance and creating potentially significant metabolic abnormalities.

g. Additional systems/conditions which may be of concern in a patient undergoing this procedure and are relevant for the anesthetic plan (e.g., musculoskeletal in orthopedic procedures, hematologic in a cancer patient)

N/A

4. What are the patient's medications and how should they be managed in the perioperative period?

Oral preoperative medications in ambulatory surgery setting

We will first address oral preoperative medications that are routinely useful in the ambulatory surgery setting even if they are not part of the patient's home regimen.

Gastric and PONV prophylaxis

If there is a history of heartburn and/or GERD and these symptoms are not managed with daily medication, H2 blockers (now generic and inexpensive, such as famotidine) are useful as a single preoperative oral dose with sips of water. If there is a history of GER chronically treated with H2 blockers at home, tachyphylaxis can occur to this drug mechanism; therefore, a proton pump inhibitor would be indicated as a single dose. If there are concerns regarding gastric motility, macrolide antibiotics (e.g., azithromycin 250 mg) may prove preferable over traditional metoclopramide (which is no longer recommended as an antiemetic due to side effect profile and relative lack of efficacy compared with safer drugs).

The antidopaminergic antiemetic perphenazine (oral 8 mg as a single dose preoperatively) is listed in the "portfolio of prophylaxis and treatment" published in the Society for Ambulatory Anesthesia (SAMBA) Consensus Guidelines for PONV (Gan et al., 2007, Anesth Analg). Perphenazine is not sedating, is opioid sparing, and does not carry a "black box" warning from the Food and Drug Administration (as does droperidol). As a CYP-2D6 antagonist, perphenazine may reduce the enzymatic effects of fast metabolism of ondansetron, which is present in approximately 13% of the general population, which may (net effect) increase the efficacy of ondansetron. This drug has identical drug-drug contraindications as droperidol (e.g., avoid if history of extrapyramidal symptoms from similar drugs, history of Parkinson's disease, etc.).

Perioperative analgesia

Acetaminophen can be a useful premedicant (15 mg/kg up to 650 mg, extended-release caplet preparations may be preferable), and appears to likely to provide short-term opioid-sparing as a single dose. Celecoxib 400 mg PO once before surgery is unlikely to adversely affect ligament-to-bone healing and appears likely to provide short-term opioid sparing as a single dose. Controversy exists whether repeated doses of celecoxib or any non–COX-specific NSAIDs impair graft healing. There is no known human evidence of either phenomenon being true.

Gabapentin and pregabalin do not carry strong indications for multimodal analgesia in the setting of a concomitant nerve block or continuous perineural catheter. These drugs combined with circulating concentrations of local anesthetics appear to be associated with profound sedation, and inability to "fast-track" or "bypass PACU." These drugs by themselves commonly cause dizziness and perhaps temporary short-term memory loss.

h. Are there medications commonly seen in patients undergoing this procedure and for which should there be greater concern?

N/A

i. What should be recommended with regard to continuation of medications taken chronically?

It is unlikely that coexisting medications for the otherwise healthy patient are causes for concern before elective ACLR. Such medications related to other clinical comorbidities can be reviewed elsewhere in this publication. Two exceptions would be NSAIDs and aspirin, both of which are commonly stopped 1 week before surgery to reduce any effects of platelet dysfunction and surgical hemostasis.

j. How to modify care for patients with known allergies

Avoid medications to which the patient is allergic.

k. Latex allergy- If the patient has a sensitivity to latex (e.g., rash from gloves, underwear, etc.) versus anaphylactic reaction, prepare the operating room with latex-free products.

Avoid use of any latex-containing equipment, This is especially a potential risk in emergent surgery where urgency may mitigate against double-checking the equipment involved for latex content.

l. Does the patient have any antibiotic allergies? (common antibiotic allergies and alternative antibiotics)

Standard antibiotic prophylaxis for this surgery is 1 to 2 g cefazolin intravenously within 60 minutes of the skin incision. If there is an open wound, antibiotics may have been started earlier. In the event of penicillin allergy, 1 g vancomycin or 900 mg clindamycin is an effective alternative, with vancomycin preferable if there is an issue of MSRA colonization.

m. Does the patient have a history of allergy to anesthesia?

Malignant hyperthermia (MH)

Documented: Avoid all trigger agents such as succinylcholine and inhalational agents. Follow a proposed general anesthetic plan: intravenous techniques with nondepolarizing muscle relaxants, propofol, and opioids are acceptable. Regional anesthesia is a highly desirable alternative in this situation. Ensure that an MH cart is available, including a copy of the MHAUS protocol.

Family history or risk factors for MH: If there is a history strongly suggestive of MH, a nontriggering technique is preferable.

Local anesthetics/ muscle relaxants: Allergy is rare; if present, offending drugs should be avoided.

5. What laboratory tests should be obtained and has everything been reviewed?

Preoperative laboratory analysis

Analysis should be driven by history and physical examination and is low yield in young healthy athletes (high probability for false positive results). Surgeons may order a prothrombin time/international normalized ratio (PT/INR) for screening purposes. Hemoglobin may be indicated if patient is a female with menstrual cycle–related bleeding excess or other abnormalities. Hemoglobin may be helpful if there is suspicion of erythropoietin “doping” (i.e., theoretical risks of polycythemia and hypercoagulability/thrombosis).

Beta HCG of the urine is ordered for women of child-bearing potential, since elite athletes may have abnormal (and/or off-cycle) menstruation. Neither type and cross match nor type and screen is typically necessary.

Intraoperative Management: What are the options for anesthetic management and how to determine the best technique?

Anesthesia care plan patient education

Often, a significant amount of time is required to explain to the patient regarding an appropriate evidence-based anesthesia care plan (i.e., incorporating regional anesthesia as the preferred first choice, relegating general anesthesia to the “backup plan”). Inadequate patient education is not a contraindication to regional anesthesia. Accounting for needed time is the fact that preoperative regional anesthetic techniques will take significantly more time before surgery to perform.

Anesthetic care plan options

General and regional anesthesia have been used to anesthetize these patients, but certain techniques have distinct advantages for the objectives of this surgery, and for the objectives of ambulatory surgery (with same-day discharge) as a separate issue. Ipsilateral hyperbaric spinal anesthesia is preferred (over any general anesthetic technique) to minimize postoperative pain, PONV, forced postanesthesia care unit (PACU) admission (as opposed to desired PACU bypass in the ambulatory surgery setting), unplanned admission, and the need for airway instrumentation. Cautious fluid replacement is required to avoid the risk of urinary retention where the combination of bladder distention (goal is less than about 400 mL urinary volume) and spinal anesthesia (especially isobaric) may force straight catheterization postoperatively before discharge home or via emergency department visit.

Total intravenous anesthesia is a reasonable “second choice” if ipsilateral hyperbaric spinal anesthesia is contraindicated (previous lumbar surgery, patient refusal despite education). Airway device selection favors laryngeal mask in the absence of contraindications. Intravenous anesthetics that do not lead to postoperative hyperalgesia include propofol, ketamine, and (off-label) dexmedetomidine, or combinations thereof.

Intraoperative PONV prophylaxis

SAMBA consensus guidelines of 2007 (Anesth Analg) were published just as ondansetron became an inexpensive generic drug. The accompanying editorial (Glass and White, 2007, Anesth Analg) recommended routine use of the following antiemetic regimen regardless of patient baseline PONV risk: 5-HT3 receptor antagonist, ondansetron 4 mg IV/corticosteroid, dexamethasone 4 mg IV/antidopaminergic. With droperidol having been ascribed a "Black Box" warning by the U.S. Food and Drug Administration (FDA), perphenazine (8 mg orally preoperatively) is emerging as an effective antidopaminergic antiemetic, and perphenazine is included in the listed repertoire of options of the SAMBA consensus guidelines.

This author has routinely used the nonsedating perphenazine preoperatively as a single 8-mg dose for most every adolescent or adult patient for 15 years without complication (exceptions: are patients with Parkinson disease, patients with a history of adverse extrapyramidal drug reactions to mechanistically similar drugs such as prochlorperazine, and patients concurrently prescribed paroxetine and aripiprazole). This author does not use aprepitant for antiemetic prophylaxis due to significant expense; however, a returning patient who had breakthrough PONV symptoms despite the described multimodal dosing scheme will be a logical candidate for aprepitant prophylaxins in addition to the other modalities described.

a. Regional anesthesia

Neuraxial: Ipsilateral hyperbaric spinal anesthesia may be preferred over isobaric spinal to minimize overall intrathecal dose and associated risks (hypotension, potentially urinary retention, etc.). Drawbacks include urinary retention due to excess fluid administration and bladder volume overload, and rare postdural puncture headache (extremely rare with 27-gauge pencil-point needles).

Chloroprocaine (due to short duration) would seem to be an unlikely choice for single-injection spinal anesthesia for ACLR, unless the surgeon is extremely fast and the patient also has dense nerve blocks in the femoral and sciatic nerve distributions. Mepivacaine is not labeled for spinal use and (like lidocaine) has a high incidence of transient neurologic syndrome. Bupivacaine is acceptable as a spinal local anesthetic, understanding the variability inherent in its regression of anesthesia.

In contexts where there is unpredictability of surgical duration, combined spinal-epidural (CSE) may be of value in the hands of experienced anesthesiologists who do not frequently (inadvertently) encounter "wet taps." CSE can allow for a smaller-dose spinal with an epidural "rapid-on/rapid-off" local anesthetic such as chloroprocaine. CSE can also be useful when the surgeon refuses to permit a sciatic nerve block for postoperative analgesia, and temporary coverage of the sacral roots is required as a spinal anesthetic effect dissipates. Chloroprocaine may be preferable to amide local anesthetics in the epidural space (as part of a CSE technique) if these patients already have amide local anesthetics placed as peripheral nerve blocks.

Peripheral nerve block: Femoral or adductor canal block (ACB), with or without sciatic block (based on graft type, described earlier) is best used as a component plan in combination with a spinal anesthetic; high-concentration local anesthetics for peripheral nerve blocks to achieve surgical anesthesia increase theoretical risks of peripheral nerve damage.

Coadministered sedation can include continuous propofol infusion with low-dose ketamine to optimize intraoperative respiratory effort and multimodal analgesia. Low-dose ketamine poses no meaningful risk of psychotomimetic reactions when coadministered with propofol. Low-dose ketamine has been shown to lead to better knee range of motion after arthroscopic surgery compared to placebo.

In addition to benzodiazepines, preoperative promethazine (also ascribed a Black Box warning by the FDA) has been shown to mitigate psychotomimetic risks of ketamine at doses used for the induction of anesthesia. Whether the nonsedating perphenazine (as preoperative antiemetic as described earlier) has similar benefits in attenuating the psychotomimetic risks of low-dose ketamine has not been studied, but this author has observed anecdotal benefit of perphenazine attenuating the psychotomimetic risks of low-dose ketamine.

Regional anesthesia perioperative complications

Failed spinal: Placement of spinal in preoperative holding area (as opposed to operating room) to ensure ample ipsilateral “soak time” and reduce risk of surgeon interruption and/or performance time pressure.

Spinal-induced hypotension: Ipsilateral hyperbaric technique typically avoids sympathectomy/hypotension, which are common with sitting and/or bilateral spinal techniques. A dose range for ACLR with recommended nerve blocks in place would be 0.9 to 1.2 mL of 0.75% bupivacaine with dextrose; larger ipsilateral dose is needed if there is no preoperative sciatic nerve block.

Transient neurologic syndrome after spinal anesthesia specifically with lidocaine or mepivacaine, far less commonly with bupivacaine or chloroprocaine.

Recent reports concluded that pediatric and adolescent patients treated with FNB for postoperative analgesia after ACLR had significant isokinetic deficits in knee extension and flexion strength at 6 months when compared with patients who did not receive a nerve block. Patients without a block were 4 times more likely to meet criteria for clearance to return to sports at 6 months. However, these reports have been criticized for flaws in the study design that may have adversely affected the conclusion of the authors.

b. General anesthesia

General anesthesia with volatile agents, with or without tracheal intubation (versus laryngeal mask), is associated with both PONV (by 20% to 70% when compared with intravenous propofol maintenance) and postoperative hyperalgesia (when the agent is at 0.1 minimum alveolar concentration).and should be avoided to the extent reasonable if the patient care goals are minimal pain/PONV, achieved PACU bypass, and avoided unplanned hospital admission. These patient care goals are both patient-centered and hospital-favored with respect to cost-utility and cost-benefit.

If patient outcomes are restricted to the minimizing of mortality, then there is likely no difference in the use of general anesthesia (with or without peripheral nerve block[s]) versus spinal anesthesia (with or without peripheral nerve block[s]).

Volatile agents as maintenance general anesthetic agents lead to absolute hyperalgesia when compared with intraoperative spinal anesthetic. Volatile agents lead to more postoperative nausea and vomiting, and longer length-of-stay in the phase 1 recovery unit when current (but not legacy) PACU discharge criteria are used.

General anesthesia is a suitable “backup” anesthesia care plan if the physician and patient are interested in minimizing anesthetic morbidity with a regional-anesthesia–specific "Plan A." General anesthetic maintenance with propofol (with or without nitrous oxide) is preferred over any inhaled agent, if the desire is to minimize postoperative anesthetic morbidity (nausea, vomiting, pain).

c. Monitored anesthesia care

Monitored anesthesia care is not a viable anesthetic option for ACL reconstruction.

6. What is the author's preferred method of anesthesia technique and why?

Preferred methods of anesthesia technique

  • Ipsilateral hyperbaric spinal anesthesia (e.g., 7.5 to 12 mg bupivacaine; lower doses in this range are achievable with preoperative femoral and sciatic nerve blocks)

  • Continuous sedation with propofol and low-dose ketamine (0.25 to 0.5 μg/kg over course of the case)

  • Spontaneous airway

  • Multimodal antiemetic prophylaxis (oral perphenazine 8 mg before surgery, intraoperative IV dexamethasone 4 mg early in surgery, with ondansetron 4 mg IV at the end of surgery)

  • Perineural catheter with local anesthetic infusion if the duration of moderate pain (or more) will exceed 24 hours in the given nerve distribution. Infusion with ropivacaine 0.2% at 5 mL/hr and intermittent bolus capability not exceeding an additional 5 mL/hr.

  • Single-injection nerve block with long-duration multimodal perineural mixture if the duration of moderate pain is unlikely to exceed 24-hour duration, such as bupivacaine 0.2% to 0.25% with 0.5 μg/kg clonidine, 2 μg/kg buprenorphine, and 1 mg dexamethasone (acknowledging off-label status of clonidine, buprenorphine, and dexamethasone for perineural use)

The goal of the overall plan is as close to 100% PACU bypass (using validated criteria for PACU bypass after regional anesthesia) and 100% same-day discharge, with appropriate perineural analgesia at home for 24 to 72 hours (for single-injection and continuous infusion, respectively).

Antibiotic prophylaxis is via SCIP guidelines for orthopedics (see http://www.aaos.org/research/committee/ptsafety/se10handout.pdf).

The choice of antimicrobial agent is cephalosporin (cefazolin, cefuroxime). If the patient has a beta-lactam allergy, use clindamycin or vancomycin. Consider preoperative screening for MRSA1 colonization. No current screening recommendations exist, per cdc.gov (accessed March 10, 2011). If the patient is infected or colonized with MRSA1, use vancomycin.

Start administration up to 60 minutes before incision for cefazolin, cefuroxime, and clindamycin. Start up to 120 minutes before incision for vancomycin. Infusion is completed 10 minutes before tourniquet inflation.

Dosing

Cefazolin is given at 1 to 2 g (2 g for patient weighing >80 kg), and cefuroxime at 1.5 g. Vancomycin and clindamycin dosing is based on patient mass.

Penicillin allergy prevalence is 2% to 3%, while absolute risk of anaphylaxis from cephalosporin is <0.001%. The risk of a cephalosporin reaction is 10 times greater for patients with a documented penicillin reaction (versus those with no penicillin reaction).

Alternative antibiotics commonly include clindamycin (side effect, Clostridium difficile colitis) and vancomycin (side effect, “red man” syndrome, which has become less common due to new, purer formulations).

Fluoroquinolones are commonly avoided due to theoretical risks of tendon rupture and are not listed in SCIP recommendations.

a. Neurologic:

N/A

b. If the patient is intubated, are there any special criteria for extubation?

N/A

c. Postoperative management

Complications

Cardiac and pulmonary complications are rare.

Acute pain

Acute postsurgical pain is primarily to be managed with the recommended nerve blocks administered preoperatively. Pain in other nerve distributions is commonly rescued with previously described doses of acetaminophen/oxycodone. It is best to “uncouple” the acetaminophen from the oxycodone to maximize the achievable acetaminophen dose without encountering hepatotoxicity concerns and to allow higher doses of acetaminophen to “spare opioids” and their side effects. Single doses of nonsteroidal anti-inflammatory drugs (NSAIDs, or COX-2 inhibitors) may also be useful for temporary relief of such pain, but orthopedic surgeons may have differing opinions of intermediate-term regular dosing of NSAIDs and risks related to ligament healing, in the absence of human data. Any surgery with inadequately treated (or untreated) postoperative pain has the theoretical risk of progressing to chronic postsurgical pain syndrome.

Neurologic

Atypical pain is based on nerve distribution. Medial superficial dysesthetic knee pain occurs due to saphenous nerve branching at the site and arthroscope-trocar insertion sites through these branches. This is common and occurs in ~3% of patients. Deep medial knee pain is typically due to deep medial knee surgery that trespasses the obturator nerve distribution. Very rarely does it require a rescue obturator nerve block for temporary relief.

Medial/lateral and/or posterior thigh pain/numbness is typically due to the inflation of the surgical tourniquet of the thigh. Circumferential numbness is typical of tourniquet pain (saphenous, lateral femoral cutaneous, and posterior femoral cutaneous nerves, respectively). Femorosciatic dysesthesia after blocks is rare and typically spares the lateral femoral cutaneous and obturator nerves. Tourniquet dysesthesia (in isolation) rarely persists beyond a few weeks; tourniquet dysesthesia in patients with concomitant nerve blocks (placed before surgery) has not been as well studied. Medial dysesthesia from groin to ankle is typically saphenous, either from tourniquet, femoral block, or a combination of both. It is typically self-limited with no potential associated motor deficits. Any surgery, and any block, has theoretical possibility of progressing to complex regional pain syndrome.

Criteria for extubation are not applicable based on this specific surgery.

Postoperative management

The best analgesic outcomes are achieved with preoperative nerve blocks and avoidance of volatile agent–induced hyperalgesia. Level of bed acuity: should achieve >90% PACU bypass and very low risk of unplanned admissions (or readmissions) with recommended anesthetic technique. PACU bypass and same-day discharge should be patient care outcome standard.

Complications related to alternating doses of opioids and sedating antiemetics are best avoided with the described preemptive planning measures.

PONV and post discharge (PD) NV: Assuming the recommended anesthesia care plan above was used (including propofol for sedation or for general anesthesia maintenance, along with preoperative perphenazine, and intraoperative dexamethasone [for nondiabetics] and ondansetron, as well as the described nerve block analgesia), PONV risk on the day of surgery should be less than 5% (reference 3). Ondansetron and dexamethasone doses can be repeated to a total day-of-surgery dose of 8 mg each. The antidopaminergic antiemetic mechanism should not have a repeated dose, in an effort to avoid extrapyramidal symptoms. Antihistamines may be useful for antiemetic rescue (e.g., dimenhydrinate or diphenhydramine). Transdermal scopolamine may also be useful for antiemetic rescue. Antihistamines and scopolamine are more sedating than single-dose perphenazine, and so dimenhydrinate/diphenhydramine/scopolamine are preferable for PONV rescue (versus prophylaxis). For a significant added expense, acustimulation wristbands specific to the P6 meridian are available for PONV rescue and PONV prevention.

Postdural puncture headache: preferential use of a 27-gauge pencil-point needle, as opposed to a 25-gauge pencil point needle. Absolute avoidance of cutting-bevel needles. Treatment rarely requires epidural blood patch in the era of thin, pencil-point spinal needles.

Urinary retention: This is rare but is possible with ipsilateral hyperbaric spinals. Controversial—The local anesthetic selected may be more influential than the choice of ipsilateral-hyperbaric spinal versus isobaric/bilateral spinal. One can consider substituting intravenous vasopressors for volume loading, and minimize bladder volume expansion.

Bladder capacity before the urge to void is experienced is 500 mL; bladder volumes commonly exceed this during spinal anesthesia. Prolonged overdistention of bladder for longer than 2 hours with volumes greater than 600 mL is associated with bladder dysfunction and generally requires one-time straight catheterization. Bladder ultrasound is an accepted and sensitive measure of bladder volume.

Fall risk: Detailed written and verbal instructions given to patient and multiple family members for non–weight-bearing, ensuring available assistants with ambulation. Daily telephone calls to reinforce non–weight-bearing instructions and to check catheter status (dressing adherence versus leakage, infusion pump dysfunction, analgesia satisfaction, etc.). Anesthesiologists may theoretically reduce fall risk by using more dilute concentrations of bupivacaine (0.0625% to 0.2%) along with the aforementioned (off-label) perineural analgesic adjuvants (clonidine-buprenorphine-dexamethasone in the doses listed above).

Catheter site infection and/or skin irritation is rare if (1) povidone-iodine is avoided as a skin antiseptic (chlorhexidine preferred), (2) tincture of benzoin is avoided as a skin adhesive liquid (Mastisol is preferred), and (3) the catheter is removed within 72 hours of insertion.

Rare: Postdural puncture headache probably does not differ from post general anesthesia headache or post ondansetron headache; postdural puncture headache rarely requires therapeutic epidural blood patch; also rare are perineural persistent paresthesia.

There is a theoretically higher risk of nerve damage if a surgical tourniquet is used, but this is not yet substantiated.

PONV prophylaxis with described nonsedating three-drug strategy of differing mechanisms (e.g., perphenazine-dexamethasone-ondansetron); propofol infusion for additional antiemetic effects, minimizing perioperative opioids, avoidance of volatile agents, and avoidance of airway devices (which is possible with preferential use of spinal anesthesia). For PONV despite prophylaxis, consider transdermal scopolamine for PDNV prophylaxis (since anticholinergic had not yet been used), or consider an intravenous antihistamine.

What's the Evidence?

Abdallah, FW, Whelan, DB, Chan, VW. "Adductor canal block provides noninferior analgesia and superior quadriceps strength compared with femoral nerve block in anterior cruciate ligament reconstruction". Anesthesiology. vol. 124. 2016. pp. 1053-64.

(A randomised, double-blind, noninferiority trial that suggests adductor canal block provides noninferior post operative pain control with better quadriceps strength compared to traditional femoral nerve block after ambulatory ACL reconstruction.)

Gan, TJ, Meyer, TA, Apfel, CC. "Society for Ambulatory Anesthesia guidelines for the management of postoperative nausea and vomiting". Anesth Analg. vol. 105. 2007. pp. 1615-28.

(An industry-sponsored consensus conference that took place while ondansetron was still patent-protected. Was published soon after ondansetron lost its patent protection.)

Pavlin, DJ, Pavlin, EG, Gunn, HC. "Voiding in patients managed with or without ultrasound monitoring of bladder volume after outpatient surgery". Anesth Analg. vol. 89. 1999. pp. 90-7.

(Classic study addressing bladder volumes and spontaneous voiding after spinal that was not ipsilateral.)

Tan, T, Bhinder, R, Carey, M, Briggs, L.. "Day-surgery patients anesthetized with propofol have less postoperative pain than those anesthetized with sevoflurane". Anesth Analg. vol. 111. 2010. pp. 83-5.

(Classic recent clinical study illustrating the long-known laboratory phenomenon that volatile agents are transiently hyperalgesic, while propofol is transiently analgesic.)

Williams, BA, Dang, Q, Bost, JE. "General health and knee function outcomes from seven days to twelve weeks after spinal anesthesia and multimodal analgesia for anterior cruciate ligament reconstruction". Anesth Analg. vol. 108. 2009. pp. 1296-302.

(Large retrospective analysis of prospectively gathered clinical outcomes data [SF-36 and Knee Outcome Survey-Activities of Daily Living] from the study in Williams et al. [2006]. Little difference in outcomes for these patients who had spinal anesthesia with either placebo or active treatment perineural femoral catheter. This study did NOT address outcomes after general anesthesia.)

Williams, BA, Kentor, ML, Vogt, MT. "Reduction of verbal pain scores after anterior cruciate ligament reconstruction with two-day continuous femoral nerve block: a randomized clinical trial". Anesthesiology. vol. 104. 2006. pp. 315-27.

(Innovative large-volume clinical pathway case series describing the economic value of the exclusive use of regional anesthesia use for outpatient ACLR, along with the value of avoiding general anesthesia in these contexts.) (Large, NIH-funded, prospective RCT [(N = 235, from 2001 to 2004] which was the first to address perineural femoral catheters for ACLR patients going home the same day after surgery. Used levobupivacaine 0.25%, which was a reasonable dose-concentration at the time of the start of the study, for an infusion-only elastomeric pump device. The dosing specifics are no longer valid in current practice, as better motor-sparing strategies have emerged. All patients received spinal anesthesia [no patients received general anesthesia]; therefore, outcome conclusions cannot be extrapolated to general anesthesia patients.)

Williams, BA, Kentor, ML, Vogt, MT. "Femoral–sciatic nerve blocks for complex outpatient knee surgery are associated with less postoperative pain before same-day discharge: a review of 1,200 consecutive cases from the period 1996–1999". Anesthesiology. vol. 98. 2003. pp. 1206-13.

(Classic large-volume clinical pathway case series that introduces the potential value of nerve block anesthesia as the "rule" for complex knee surgery outpatients [as opposed to the "exception"].)

Williams, BA, Kentor, ML, Vogt, MT. "The economics of nerve block pain management after anterior cruciate ligament reconstruction: hospital cost savings via associated PACU bypass and same-day discharge". Anesthesiology. vol. 100. 2004. pp. 697-706.

(Innovative large-volume clinical pathway case series describing the economic value of the exclusive use of regional anesthesia use for outpatient ACLR, along with the value of avoiding general anesthesia in these contexts.)

Luo, TD, Ashraf, A, Dahm, DL. "Femoral nerve block is associated with persistent strength deficits at 6 months after anterior cruciate ligament reconstruction in pediatric and adolescent patients". The American Journal of Sports Medicine. vol. 43. 2015. pp. 331-336.

Boretsky, K, Yen, YM, Harner, CD. "Femoral nerve block for anterior cruciate ligament reconstruction--Do we have the information we need? Letter to the editor". The American Journal of Sports Medicine. vol. 43. 2015. pp. NP30.

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