Proximal tibial osteotomy for genu varum: Radiological evaluation of deformity correction with a plate vs external fixator

Table 1 Patients demographic

Demographics	Plate and screw (n = 43)		External fixator (n = 36)		P value
	n	Mean (range)	n	Mean (range)
Age (yr)	43	46.3 (19-68)	36	42.1 (24-67)	0.14
BMI (kg/m2)	39	26.0 (18.7-35.0)	11	30.0 (20.3-39.1)	0.08
Sex (female)	43	32.6%	36	47.2%	0.16

BMI: Body mass index.

Table 2 Patients demographic

Demographics	Plate and screw (n = 43)				External fixator (n = 36)				P value
	N1 (n = 25)		O (n = 18)		N (n = 23)		O (n = 13)		N vs N	O vs O	N vs O (plate and screw)	N vs O (ex fix)
	n	Mean (range)	n	Mean (range)	n	Mean (range)	n	Mean (range)
Age (yr)	25	41.7 (19-68)	18	52.7 (32-67)	23	39.9 (24-55)	13	46.1 (30-67)	0.61	0.12	< 0.01	0.11
BMI (kg/m2)	23	24.1 (18.7-33.5)	16	28.8 (22.4-35.0)	8	27.6 (20.3-39.1)	3	36.4 (33.1-38.4)	0.15	0.03	< 0.001	0.01
Sex (female)	25	36.0%	18	27.8%	23	47.8%	13	46.2%	0.41	0.25	0.57	0.92

¹In this table and all subsequent ones. T: Total group; N: Neutral goal; O: Overcorrected; BMI: Body mass index.

Table 3 Mechanical axis deviation changes

MAD	Plate and screw		External fixator		P value
	N	O	N	O	N vs N	O vs O
	Mean (range)	Mean (range)	Mean (range)	Mean (range)
MAD pre-op (mm)	24.5 med (14 med to 42 med)	25.9 med (11 med to 37 med)	21.3 med (9 med to 42 med)	23.0 med (11 med to 42 med)	0.15	0.38
MAD post-op (mm)	4.3 lat (1 lat to 13 lat)	12.7 lat (3 lat to 20 lat)	3.5 (7 med to 10 lat)	9.5 (5 med to 20 lat)	0.40	0.08

MAD: Mechanical axis deviation; N: Neutral goal; O: Overcorrected; op: Operation.

Table 4 Medial proximal tibial angle changes

MPTA	Plate and screw		External fixator		P value
	N	O	N	O	N vs N	O vs O
	Mean (range)	Mean (range)	Mean (range)	Mean (range)
ΔMPTA (degree)	6.8 (0-13)	9.6 (3-14)	5.7 (2-10)	6.2 (-4 to 15)	0.25	0.05

MPTA: Medial proximal tibial angle; N: Neutral goal; O: Overcorrected.

Table 5 Accuracy of mechanical axis deviation correction

Accuracy	Plate and screw			External fixator			P value
	T	N	O	Total	N	O	T vs T	N vs N	O vs O
	Mean (range)	Mean (range)	Mean (range)	Mean (range)	Mean (range)	Mean (range)
Accuracy (%)	96.1 (60 to 100)	94.8 (60 to 100)	97.7 (87 to 100)	98.2 (79 to 100)	98.2 (82 to 100)	98.2 (79 to 100)	0.18	0.17	0.82

T: Total group; N: Neutral goal; O: Overcorrected.

Table 6 Changes in Caton-Deschamps Index

CDI	Plate and screw	External fixator	P value
	Mean (range)	Mean (range)
CDI pre-op (unitless)	1.1 (0.7-1.6)	1.0 (0.8-2.1)	0.77
CDI post-op (unitless)	0.9 (0.4-1.1)	1.1 (0.8-1.9)	0.01
ΔCDI (unitless)	-0.2 (-0.5 to 0.2)	0.02 (-0.2 to 0.2)	< 0.001
%ΔCDI (%)	-19.2 (-47.0 to 21.9)	3.1 (-8.1 to 25.0)	< 0.001

CDI: Caton-Deschamps Index.

Table 7 Posterior proximal tibial angle changes

PPTA	Plate and screw	External fixator	P value
	Mean (range)	Mean (range)
ΔPPTA (degree)	-3.3 (-9 to 1)	-1.7 (-11 to 4)	0.14
%ΔPPTA (%)	-4.1 (-11.3 to 1.3)	-2.0 (-12.8 to 5.1)	0.11

PPTA: Posterior proximal tibial angle.

Table 8 Joint line obliquity angle changes

JLOA	Plate and screw	External fixator	P value
	Mean (range)	Mean (range)
ΔJLOA (degree)	1.6 (4 med to 3 lat)	0.9 (3 med to 2 lat)	0.04

JLOA: Joint line obliquity angle.