Does surgeon handedness affect the outcomes after primary total knee arthroplasty? A retrospective cohort study

Table 3 Comparing the methods used for tibial component insertion, n (%)

		IM (188 patients)		EM (182 patients)		P value	OR (95%CI)
Total number	Group D	88 (46.8)		89 (48.9)		0.6871
	Group N	100 (53.2)		93 (51.1)
MPTA (degrees), mean ± SD (range)	Group D	88.86 ± 3.26 (78 to 95)		88.93 ± 1.76 (84 to 93)		0.8621
	Group N	88.56 ± 3.00 (80 to 98)		90.38 ± 1.99 (84 to 95)		0.0011,a
Safe zone 90° to 87°		Within	Outside	Within	Outside
	Group D	32 (36.4)	56 (63.6)	63 (70.8)	26 (29.2)	0.0012,a	4.24 (2.26-7.96)
	Group N	43 (43)	57 (57)	37 (39.8)	56 (60.2)	0.6502	1.19 (0.68-2.09)
	P value	0.3532		0.0012,a
	OR (95%CI)	1.32 (0.73 to 2.38)		3.67 (1.98 to 6.80)

¹Students' t-test compares the mean difference between variables.

²χ² test compares proportions between both groups.

^aP value < 0.05 was considered significance.

IM: Intramedullary; EM: Extramedullary; MPTA: Medial proximal tibial angle; OR: Odds ratio; CI: Confidence interval.