Evaluation of Safety and Efficacy of Traction, Closed Reduction, and Subsequent Hip Fixation in Hilgenreiner Brace in Patients with Severe Forms of Hip Developmental Dysplasia

Table 2

Basic Severin classification system.

Class	X-ray appearance	Angle of the central margin
I	Normal	15°–25°
II	Medium deformity of the femoral head, neck of the femur, or the acetabulum	15°–25°
III	Dysplasia without subluxation	<15° (6 to 13 years) <20° (>14 years)
IV	Subluxation	>0°
V	The femoral head is articulated with a pseudoacetabulum in the proximal part of the original acetabulum
VI	Redislocation