Table 2.

Regional Analgesia for TKA

Analgesic Procedure	Advantages	Disadvantages	Contraindications
Intrathecal analgesia	• Relatively easy technique • Bilateral analgesic effect for bilateral TKA	• Effect in sympathetic innervation (urinary retention and hypotension ) • Respiratory depression related to intrathecal opioid use • Pruritus • Unnecessary bilateral block • Risk of infection and nerve damage • Delays mobilization	• Elevated intracranial pressure • Infection on the injection site • Risk of hypotension (hypovolemia) • Thrombocytopenia or coagulopathy
Femoral nerve block	• Easy access with or without ultrasound guidance • Excellent analgesia • Good predictable course of catheter with ultrasound guidance	• Delays mobilization • High risk of falls	• Patient inability to positioning • Allergy to LAs • Preexisting coagulopathies (endogenous or iatrogenic) • Active infection on the injection site • If no USG guidance, anatomic anomalies • affecting physical • landmarks identification • Pre-existing neuropathies affecting the distribution of the block
Sciatic nerve block (posterior)	• Analgesia on the posterior aspect of the knee • Adjuvant effect on anterior compartment blocks	• Relatively deep block • Requires prone/ semiprone position • Delays mobilization
Adductor canal block (ACB)	• Allows early mobilization and recovery time • Continuous technique provides the highest analgesic effect73 • Higher opioid-sparing effect than LAI78,79 • Easy ultrasound guide access68	• Tunneling is required in some cases
iPACK	• Adjuvant analgesic effect on ACB • Analgesia on the posterior aspect of the knee • Minimal impact on mobilization	• Limited to single shot technique • Short analgesic effect • Risk of foot drop
Local anesthetic infiltration (LAI)	• Easy intraoperative administration • Adjuvant analgesic effect • Minimal impact on mobilization	• Increased risk of toxicity101 • Short analgesic effect • Risk of infections with intraarticular catheter
Genicular nerve block	• No risk of toxicity (no LA use)	• Requires Fluoroscopic and trained staff • USG guidance still in investigation • Scarce clinical evidence	• Bleeding diathesis • Infection at the site
Cryoanalgesia	• No risk of toxicity (no LA use)	• Unpredictable analgesic duration • Risk of permanent sensory and motor block • Scarce clinical evidence	• Raynaud syndrome • Cryoglubulinemia • Bleeding disorders • Active infection on the injection site120

Comparison among postoperative analgesic techniques for TKA. All thechniques are rarely associated with infectious complications. Neuroaxial procedures are related with 1.1- 2.5 infections per 100.000 neuroaxial blocks. Risk factors of infectious complications in peripheral nerve blocks are: ICU hospitalization, duration of catheter more than 48 hrs, lack of antibiotic prophilaxis, catheters in the femoral region and number of catheter dressing changes are considered risk factors of infectious complications in peripheral nerve blocks.