3.1. Anesthesia approach

The potential impact of different types of anesthetic technique administered during TKA on postoperative outcome remains controversial. Different anesthesia approaches may affect the incidence of surgical site infection, urinary retention, and also pose different impact on medical cost. There are two anesthetic techniques that are often used in TKA, general anesthesia and spinal anesthesia. In current literature, spinal anesthesia is a more recommended anesthetic approach as it is associated with more favorable postoperative outcomes, lower complication rate and lower 30-day mortality. Patients receiving spinal anesthesia are observed to experience shorter length of hospital stay, lower rate of pulmonary embolism, pneumonia, cerebrovascular events, acute renal failure and the need for blood transfusion [16, 17].

Regional anesthesia also plays a role in fast track program. Peripheral nerve blocks such as femoral nerve blocks and adductor canal blocks are often used in TKA in assistance with spinal or general anesthesia. It is assumed that peripheral nerve blocks provide supplemental anesthesia and analgesia effect during the perioperative and postoperative periods. Reported benefits include shorter length of hospital stay, less opioid consumption and earlier participation in physical therapy [18–20]. Reduced risk of hypotension and urinary retention were also observed in patients receiving regional anesthesia comparing with patients receiving epidural anesthesia.

Local infiltration anesthesia (LIA) has been gaining focus in recent years, as several wellconducted studies had indicated the potential benefits postoperatively [21, 22]. LIA consists of a mixture of medications that include long-acting anesthetic, NSAIDs and epinephrine. Regimen varies from institution to institution. It is injected to the posterior capsule, collateral ligaments, capsular incision, quadriceps muscle tendon, and the adjacent subcutaneous tissues. Significant reduction in opioid consumption, improvement in pain VAS score and patient satisfaction are observed in patients receiving LIA [21, 22].
