Increase in early wound leakage in total knee arthroplasty with local infiltrative analgesia (LIA) that includes epinephrine: a retrospective cohort study

Figures & data

Table 1. Patient characteristics. Values are number (%) unless otherwise specified

	Control group	Study group
	n = 251	n = 232	p-value
Mean age (SD) ^a	69 (8.8)	69 (8.6)	0.5
Female sex ^b	154 (61)	134 (58)	0.4
Smoking ^b	34 (14)	11 (5)	0.001
Use anticoagulants ^b	80 (32)	81 (35)	0.5
Diabetes ^b	47 (19)	36 (16)	0.4
Early wound leakage ^b	42 (17)	55 (24)	0.06

^a T-test; ^b chi-square test.

Direct acyclic graph describing the hypothesized causal pathways of the selected possible confounders.

Table 2. Results of log-binomial models of the ROPI + protocol versus ROPI– protocol

Factor	RR (95% CI)
Early wound leakage—crude model	1.4 (0.99–2.0)
Early wound leakage—adjusted for surgeon	1.4 (1.0–2.0)
NRS pain assessment	0.95 (0.9–1.0)

RR = relative risk; CI = confidence interval;

NRS = numerical rating scale.