Table 2.

Agreement for conventional imaging and 3D printed models among four residents

Parameter	Conventional			Conventional + 3D
	Kappa		Agreement	Kappa		Agreement	∆ kappa		p value
Characteristic
Humeral head split	0.48	(0.21-0.74)	Moderate	0.66	(0.37-0.95)	Substantial	0.18	(-0.21 to 0.58)	0.18
Medial hinge displacement > 2 mm	0.02	(-0.15 to 0.20)	Slight	0.07	(-0.18 to 0.33)	Slight	0.05	(-0.25 to 0.35)	0.74
Metaphyseal extension > 8 mm	0.27	(0.02-0.52)	Fair	0.28	(0.08-0.48)	Fair	0.01	(-0.32 to 0.33)	0.48
Surgical neck fracture	0.02	(-0.20 to 0.24)	Slight	0.13	(-0.15 to 0.40)	Slight	0.11	(-0.25 to 0.46)	0.28
Anatomic neck fracture	0.17	(-0.03 to 0.38)	Slight	0.28	(0.00-0.55)	Fair	0.10	(-0.24 to 0.45)	0.57
Displacement of the humeral head	0.29	(0.07 to 0.52)	Fair	0.1	(-0.07 to 0.26)	Slight	0.19	(-0.79 to 0.40)	0.52
LT displacement >10 mm	0.18	(-0.06 - 0.41)	Slight	0.17	(-0.06 to 0.40)	Slight	0.01	(-0.33 to 0.32)	0.97
GT displacement >10 mm	0.16	(-0.06 to 0.38)	Slight	0.13	(-0.13 to 0.39)	Slight	0.03	(-0.37 to 0.31)	0.43
Fracture pattern
Neer classification	0.14	(0.03-0.25)	Slight	0.04	(-0.05 to 0.13)	Slight	0.10	(-0.25 to 0.04)	0.16
Hertel classification	0.14	(0.00-0.27)	Slight	0.13	(0.03-0.23)	Slight	0.01	(-0.17 to 0.15)	0.46

A kappa value less than 0 indicates poor agreement; a ∆ kappa value less than 0 indicates that agreement for conventional imaging with 3D models is lower than for conventional imaging only; LT = lesser tuberosity; GT = greater tuberosity.