Table 4.

Description of the scientific publications of PAI in TKA.

Study	Groups	Study type	Length of followup	Results
Badner et al. [3]	Group 1: intraarticular 150 mg bupivacaine and 1:200,000 epinephrine before incision and 30 mL of saline after wound closure (N = 28)	Randomized, double-blind, controlled study	24 hours	Intraarticular injection of bupivacaine and epinephrine after wound closure decreased the need for narcotics (59 ± 27 mg versus 81 ± 30 mg morphine, respectively) and increased the ROM motion.
	Group 2: intraarticular 30 mL saline before incision and 150 mg bupivacaine and 1:200,000 epinephrine after wound closure (N = 27)
	Group 3: 30 mL saline for both intraarticular injections (N = 27)
Mauerhan et al. [19]	Group 1: intraarticular saline (N = 27)	Randomized, double-blind, controlled study	48 hours	The total amount of postoperative pain medication used in the first 24 hours after surgery was not different between the 4 treatment groups.
	Group 2: intraarticular 5 mg morphine sulfate (N = 26)
	Group 3: intraarticular 50 mg bupivacaine (N = 24)
	Group 4: intraarticular 5 mg morphine sulfate and 50 mg bupivacaine (N = 28)
	All injections given immediately after wound closure
Klasen et a. [16]	Group 1: postoperative epidural boluses of 2.5 mg of morphine, as requested by the patient (N = 10)	Randomized, controlled	24 hours	No differences in VAS were observed between the three groups.
	Group 2: intraarticular 1 mg morphine after wound closure, followed with PCA with morphine (N = 10)
	Group 3: epidural saline and intraarticular saline, followed by PCA with morphine (N = 10)
Ritter et al. [22]	Group 1: intraarticular 10 mg morphine (N = 109)	Randomized, double-blind, controlled study	24 hours	There were no differences between the groups in use of Demerol® and/or Toradol®, length of stay in hospital, or pain rating. Groups 1 and 4, whose injections included morphine, used more morphine in the first 24 postoperative hours than Group 2 or Group 3.
	Group 2: intraarticular 25 mg bupivacaine (N = 114)
	Group 3: intraarticular saline (N = 97)
	Group 4: intraarticular 10 mg morphine 22.5 mg bupivacaine (N = 117)
	All injections given immediately after wound closure
Browne et al. [5]	Group 1: intraarticular 100 mg bupivacaine (N = 30)	Randomized, double-blind, controlled study	24 hours	The group receiving bupivacaine had a shorter time to discharge from the postanesthesia care unit than the group receiving saline.
	Group 2: intraarticular 20 mL saline (N = 30)			Although bupivacaine resulted in lower pain scores and reduced narcotics during the 24-hour period, the difference was not significant between groups.
	All injections given immediately after wound closure
Lombardi et al. [17]	Group 1: narcotics alone (N = 138 patients)	Retrospective analysis	48 hours	Patients receiving soft tissue and intraarticular injection had improved pain control in the immediate postoperative period, decreased blood loss, and decreased need for rescue narcotics and reversal agents.
	Group 2: intraoperative injection 200 mg bupivacaine with 1:200,000 epinephrine and 10 mg morphine, 2/3 injected into the soft tissues and 1/3 injected into the joint (N = 171 patients)
Vendittoli et al. [27]	Group 1: narcotics alone (N = 20)	Randomized, double-blind, controlled study	120 hours	Morphine consumption was significantly lower in the local analgesia group than in the control group up to 40 hours after surgery. Both groups achieved a similar amount of knee flexion on the fifth postoperative day.
	Group 2: PAI with 275 mg ropivacaine, 30 mg ketorolac, and 0.5 mL of adrenaline (1/1,000) before component implantation, followed with an additional 125 mg ropivacaine before wound closure (N = 22)
Toftdahl et al. [26]	Group 1: continuous femoral nerve block (N = 37)	Randomized, controlled	48 hours	More patients receiving periarticular and intraarticular infiltration could walk > 3 m, had lower pain scores during activity, and had lower consumption of opioids on the first postoperative day.
	Group 2: periarticular and intraarticular infiltration with 300 mg ropivacaine, 30 mg ketorolac, and 0.5 mg epinephrine at the end of surgery, and 2 postoperative injections of these substances through an intraarticular catheter (N = 39)
Carli et al. [8]	Group 1: continuous femoral nerve block (N = 20)	Randomized, double-blind, controlled study	6 weeks	Patients in the femoral nerve block group had lower opioid consumption in the 48-hour postoperative period and better recovery at 6 weeks than patients in the PAI group.
	Group 2: periarticular and intraarticular infiltration with 200 mg ropivacaine, 30 mg ketorolac, and 0.5 mg epinephrine (N = 20)
Current study	Group 1: continuous femoral nerve block (N = 30)	Randomized, double-blind, controlled study	120 hours	Patients in the PAI group had lower opioid consumption and lower pain at rest during the first 8 hours postoperative. More patients in the femoral nerve block group experienced quadriceps motor block. Patients in the PAI group experienced better capacity to perform the straight leg raise test and active knee extension and had longer walking distances in the postoperative period.
	Group 2: periarticular infiltration (PAI) with 275 mg ropivacaine, 30 mg ketorolac, and 0.5 mL adrenaline (1/1,000) before component implantation, followed with an additional 125 mg ropivacaine before wound closure (N = 29)

PAI = periarticular anesthetic infiltration.