Reduced morphine consumption and pain intensity with local infiltration analgesia (LIA) following total knee arthroplasty

Figures & data

Figure 1.  Flow chart for the study.

Table 1.  Demografic data and duration of surgery. Values are mean (SD)

	Group A	Group P
No. of females/males	13/11	13/11
Age, years	72 (9)	70 (9)
Weight, kg	82 (14)	81 (10)
Height, cm	168 (9)	169 (8)
Body mass index	29 (5)	28 (3)
ASA, I / II / III	7 / 17 / 0	5 / 18 / 1
Operation time, min	93 (20)	87 (19)

Group A (active): intraoperative and postoperative injections.

Group P (placebo): no intraoperative or postoperative injections.

ASA physical status I: normal health; II: systemic disease with no limited activity; III: systemic disease with limited activity.

Table 2.  Consumption of analgesics

	Group A median (range)	Group P median (range)	p-value
Morphine i.v. (mg)
0–24 h	17 (1–74)	65 (36–131)	< 0.001
24–48 h	0.5 (0–17)	22 (0–52)	< 0.001
0–48 h	18 (1–74)	87 (36–160)	< 0.001
Tramadol orally (mg)
0–24 h	0 (0–200)	0 (0–100)	0.01
24–48 h	375 (0–400)	200 (0–400)	0.04
0–48 h	400 (0–500)	200 (0–500)	0.008
Total analgesics ^a (mg)
0–48 h	54 (4–114)	109 (37–211)	< 0.001

^a Total analgesic consumption was calculated by converting oral tramadol to the equivalent dose of intravenous morphine (100 mg tramadol orally = 10 mg morphine intravenously).

Figure 2.  Postoperative pain at rest. VAS scores are presented as median and interquartile range (IQR). ^a p < 0.001 (3, 6, and 12 h); p = 0.005 (21 h); p = 0.003 (22 h); p = 0.002 (27 h).

Figure 3.  Postoperative pain on movement. VAS scores are presented as median and interquartile range (IQR). ^a p < 0.001 (3, 6, 12, and 22 h); p = 0.005 (27 h); p = 0.01 (48 h).

Table 3.  Mobilization and patient satisfaction

Outcome	Group A median (range)	n	Group P median (range)	n	p-value
Knee extension (degrees)
Preop.	5 (0–30)	23	5 (0–20)	19
24 h postop.	10 (0–20)	24	10 (0–20)	19	0.4
48 h postop.	10 (0–15)	23	10 (0–15)	21	0.4
Discharge	10 (0–10)	24	10 (5–10)	23	0.01
3 days postop.	10 (0–15)	22	10 (0–15)	22	0.4
3 months postop.	5 (0–10)	20	5 (0–15)	23	0.6
Knee flexion (degrees)
Preop.	120 (90–153)	23	120 (100–135)	19
24 h postop.	90 (60–105)	24	60 (30–85)	23	< 0.001
48 h postop.	75 (50–105)	23	60 (40–90)	22	0.003
Discharge	85 (60–115)	24	75 (60–100)	23	0.2
3 days postop.	75 (60–110)	22	62 (45–90)	22	0.09
3 months postop.	112 (100–125)	20	110 (90–130)	22	0.3
TUG test (seconds)
Preop.	10 (6–26)	21	9 (6–28)	17
48 h postop.	22 (10–51)	15	27 (8–35)	8	na ^a
3 days postop.	18 (9–49)	16	20 (8–80)	12	na ^a
7 days postop.	18 (10–48)	24	17 (7–65)	21	0.8
14 days postop.	14 (7–42)	22	10 (6–25)	22	0.5
3 months postop	8 (6–16)	20	7 (5–19)	23	0.8
Patient satisfaction
1 day postop.	4 (2–4)	23	3 (1–4)	20	< 0.001
7 days postop.	3 (1–4)	23	3 (1–4)	20	0.02 ^b
Oxford knee score
Preop.	39 (26–49)	23	40 (27–42)	20
14 days postop.	33 (18–42)	20	32 (25–45)	21	0.9
3 months postop.	16 (12–37)	20	16 (12–28)	23	0.8
EQ-5D
Preop	0.66 (0.06–0.80)	23	0.20 (0.03–0.73)	23
3 months postop.	1 (0.59–1)	21	1 (0.69–1)	23	1

n: number of patients who participated varied depending on patients' ability to cooperate.

TUG test: Timed up and go test.

^a na: not applicable. No statistical calculations were done due to the small number of patients in each group.

^b Patient satisfaction: Excellent = 4, good = 3, inadequate = 2, poor = 1. In group A, 20/23 scored 3–4 as compared to 12/20 in group P 7 days postoperatively.

Oxford knee score: 12 (the best possible) to 60 (the worst possible).

EQ-5D health outcome: 1 = perfect health; 0 = poor health.

Table 4.  Side effects. Values are number of patients in each category

	Group A (n = 24)	Group P (n = 23)	p-value
Nausea
0–24 h	9	16	0.03
24–48 h	4	8	0.2
Vomiting
0–24 h	5	9	0.2
24–48 h	1	3	0.4
Pruritus
0–24 h	1	9	0.004
24–48 h	0	6	0.009
Sedation
0–24 h	0	5	0.02
24–48 h	0	1	0.5