Anesthesia for total knee replacement surgery in a patient with positive stress test

Madam,

Joint replacement surgeries are in increasing trend to improve the life quality of aging population. A 65-year-old female with a body mass index of 37.7 kg/m² was advised total knee replacement (TKR) in view of constant rest pain, swelling, and deformity hampering daily activity. The patient was virtually bedridden. She had hypertension since 8 years. She underwent percutaneous transluminal coronary angioplasty of the left anterior descending artery and was on medical treatment. General physical and systemic examination revealed no abnormality with anticipated difficult airway. Preoperative cardiac evaluation revealed poor cardiac performance with T-wave inversion in the inferior and lateral leads. Her baseline echo revealed that mid anterior septum, apex, and basal inferior wall were severely hypokinetic with left ventricle ejection fraction (LVEF) of 45%, mild left ventricular hypertrophy, and mild mitral regurgitation. While undergoing dobutamine stress echo (DSE) with dobutamine infusion at 20 mcg/kg/min, her mid anterior septum, distal interventricular septum, and distal anterior wall became akinetic with LVEF 40%. The patient complained of uneasiness with electrocardiography showing frequent premature ventricular complexes and bigeminy. Her DSE was positive for myocardial infarction. Blood investigations ruled out end-organ damage. Renal, liver, and coagulation parameters were in normal limit. Her preoperative hemoglobin, serum sodium, and serum potassium were 10.8 g/dL, 135 mmol/L, and 3.9 mmol/L, respectively.

After a board meeting, the patient was accepted for two-staged TKR under American Society of Anesthesiologists (ASA) grade IV in view of her present cardiac status.

Given the risk of perioperative complications, we opted to perform ultrasound-guided right continuous femoral nerve block (FNB) with single-shot sciatic nerve block (SNB) after ASA standard monitoring and arterial cannulation. Epidural catheterization was done for rescue anesthesia perioperatively.

Under all aseptic conditions, right SNB was administered in left lateral position with partial flexion at hip and knee. Under ultrasound guidance, sciatic nerve was identified in transverse plane using curvilinear probe in subgluteal region [Figure 1a] and was confirmed by tracing it till popliteal fossa. A 5-cm 17-G stimucath needle was inserted out of plane to approach sciatic nerve and was confirmed by plantar flexion of the right foot in response to the stimulating current of 1 mA. Local anesthesia spread pattern on ultrasound was observed while injecting 20 mL of 0.5% ropivacaine. Then, the patient was given right FNB under ultrasound guidance using 20 mL of 0.5% ropivacaine in supine position [Figure 1b]. Femoral catheter was inserted and fixed with LOCKIT Plus^® to prevent dislodgement of the catheter. Infusion of 0.5% ropivacaine was started at 5 mL/h. Meanwhile, tourniquet was applied and the limb was prepared for surgery. After 20 min, motor and sensory blockade was checked and surgery started. Peripheral nerve block was supplemented by intravenous 1 mg midazolam and 50 mcg fentanyl. Vitals were within normal limits. The surgery lasted for 1.5 h with tourniquet time of 61 min and was uneventful. The total fluid given was 700 mL with output 100 mL. Postoperatively, infusion 0.2% ropivacaine was started at 5 mL/h for postoperative analgesia. The patient was comfortable perioperatively without rescue epidural analgesia. She was hemodynamically stable and was shifted to the surgical intensive care unit.

Figure 1.

(a) Sciatic nerve block and (b) femoral nerve block. AT- adipose tissue, GMM – Gluteus maximus muscle, GT – greater trochanter, IT – ischial tuberosity, SN – sciatic nerve, QF – Quadratus femoris muscle, F.I. – Fascia iliaca, F.A. – Femoral artery, F.V. – Femoral vein, F.N.- Femoral nerve, L.A.- Local anesthesia

TKR is one of the popular surgeries involving cost, complications, and outcome. With increased risk associated with one-stage bilateral TKR, the final decision whether to attempt simultaneous or staged bilateral TKR should be made on individual basis.[1]

Urban et al.[2] published guidelines for unilateral indication of TKR including age more than 75 years, ASA class III, positive stress test, and poor ventricular function. Therefore, in this case two-staged bilateral TKR was opted.

Combined spinal epidural anesthesia (CSEA) provides excellent surgical conditions, thus becoming the anesthesia of choice in TKR.[3]

CSEA was not used as it would have affected both the limbs which was not required and predispose the patient to cardiac and other complications. Dusanka et al. demonstrated that the FNB and SNB were safer when compared with epidural group on the first postoperative day. Moreover, they also found that motor blockade was more intense in the operated limb on the day of surgery and the first postoperative day in the peripheral nerve block group, whereas the nonoperated limb was more blocked in the epidural group on the day of surgery.[4]

The knee joint is supplied by femoral, obturator, and sciatic nerves. The obturator nerve (L2, 3, 4) supplies the adductor muscles on the medial side of the thigh [Tables 1 and 2]. Anterior innervation groups include femoral, common peroneal, and saphenous nerves. Posterior innervation group includes posterior articular nerve of tibial nerve.[5]

Table 1.

Femoral nerve block

Femoral nerve is made from posterior roots L2, L3, and L4 (anterior roots L2, L3, L4 - obturator nerve) Largest nerve branch of lumbar plexus
COURSE: emerges lateral to psoas major - descends beneath inguinal ligament - femoral triangle - lateral to femoral vessels - in sulcus in iliopsoas muscle underneath fascia iliaca
BRANCHES: anterior and medial cutaneous branches, articular branches to hip and knee joint, muscular branches to sartorius and quadratus femoris and terminate as saphenous nerve
ANESTHESIA: anterior and medial thigh down to knee along with variable strip of skin on medial leg and foot
Femoral artery is extension of external iliac artery and lies between anterior superior iliac spine and pubic symphysis. Below inguinal ligament, it divides into profunda femoris artery and superficial femoral artery. Lateral circumflex artery branch of profunda femoris artery separate divisions of femoral nerve. Therefore, block should be given proximal to division of femoral artery.
POSITION: supine	PROBE: linear transducer (7-12 MHz)
PROBE POSITION: placed over inguinal crease
IDENTIFICATION OF NERVE: hyperechoic roughly triangular or oval shaped at a depth of 2-4 cm
TECHNIQUES: In plane from lateral to medial/out of plane from inferior to superior
As needle passes through fascia lata and fascia iliaca, “Pop” sensations are often felt
Needle placement is confirmed - after careful aspiration, hydrodissection is done
While injecting 15-20 mL of LA to surround the nerve, LA spread pattern is seen
Under ultrasound guidance, catheter advancement is done
POSITION OF CATHETER: 2-4 cm in the vicinity of the femoral nerve just deep to the fascia iliaca To prevent catheter dislodgement, the catheter is secured by tunneling and then taping it to skin Infusion of LA is started mostly at 5 mL/h

LA=Local anesthetic

Table 2.

Sciatic nerve block

Sciatic nerve is formed from lumbosacral plexus comprising ventral rami of L4, 5, S1, S2, S3 Largest nerve of the body
COURSE: leaves the pelvis from infrapiriform fossa of greater sciatic foramen along with posterior femoral cutaneous nerve - after emerging from piriformis - descends on posterior surface of the superior gemellus, obturator internus, inferior gemellus, and quadratus femoris muscles - deep to gluteus muscles between ischial tuberosity and greater trochanter - enters the posterior thigh - deep to the long head of the biceps femoris - popliteal fossa
TRANSGLUTEAL LEVEL: lies between the greater trochanter of the femur and the ischium tuberosity, just below the gluteus maximus muscle SUBGLUTEAL LEVEL: located immediately deep to gluteus maximus muscle and superficial to quadratus femoris muscle, lateral to the origin of the biceps femoris muscle at the ischial tuberosity and medial to the greater trochanter Depth of sciatic nerve changes from subgluteal region 3-5 cm to mid thigh 4-8 cm to popliteal fossa 2-4 cm while tracing sciatic nerve till popliteal region by ultrasound
BRANCHES: apex of popliteal fossa - terminates into common peroneal nerve and tibial nerve
ANESTHESIA: posterior aspect of thigh, knee, and whole leg excluding variable strip of skin on medial leg and foot
POSITION: Lateral	PROBE: curvilinear transducer (2-5 MHz)
PROBE POSITION: placed over posterior thigh at or below gluteal crease
IDENTIFICATION OF NERVE: hyperechoic roughly triangular or oval shaped at depth of 3-5 cm
TECHNIQUES: anterial and posterior (transgluteal and subgluteal approach)
Once sciatic nerve identified under ultrasound [Figure 1a], the needle is inserted in-plane, typically from the lateral aspect of the transducer and advanced toward the sciatic nerve
Using nerve stimulation (1.0 mA, 0.1 ms) - motor response of the calf or foot
After careful aspiration, hydrodissection done to confirm needle tip While injecting 15-20 mL of LA - spread pattern is observed on ultrasound LA injected to surround the nerve circumferentially

LA=Local anesthetic

Peripheral nerve blocks including FNB and SNB are one of the current trends used for postoperative analgesia in patients undergoing TKR.[6]

In this case, TKR was performed under ultrasound-guided continuous FNB and single-shot SNB. SNB was given along FNB so as to cover the posterior compartment of the knee. Among several approaches, we preferred subgluteal approach as the patient was obese and nerve is superficial when compared with other positions and imaging is not interfered by the bones. Systemic reviews demonstrated that addition of SNB provides additional postoperative analgesia with FNB in patients undergoing TKR.[7]

Ultrasound helps in confirmation of femoral nerve and catheter placement with local anesthetic spread. While administering SNB, we used both ultrasound and nerve stimulation technique to confirm sciatic nerve. Ultrasound helps in nerve localization and monitoring spread of local anesthetic along the needle placement with confirmatory evidence by motor response obtained during nerve stimulation. The motor response of hamstrings, foot, or toes obtained during nerve stimulation often provides contributory information. Ultrasound may facilitate more rapid onset of block and prolong duration of block. Use of ultrasound also decreases the doses of drug and the incidence of local anesthetic toxicity.[8]

Continuous FNB with single-shot SNB efficiently provided anesthesia and postoperative analgesia for TKR. Perioperatively, the patient was comfortable with no hemodynamic disturbances as demonstrated by Fanelli et al.[9] for leg surgery. The patient did not require any epidural top up or rescue anesthesia perioperatively.

These blocks are reported to cause quadriceps paresis, intravascular injection, hemotoma, and nerve injury/foot drop.[6] No such complication was observed in our case.

To conclude, ultrasound-guided continuous FNB with single-shot SNB can be used as an anesthetic technique for TKR. They are perhaps ideal for high-risk candidates who cannot tolerate altered hemodynamics.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.