Congenital hip dislocation

 

Crowe classification
In 1979 Dr. John F. Crowe  et al. proposed a classification to define the degree of malformation and dislocation. Grouped from least severe Crowe I dysplasia to most severe Crowe IV. This classification is very useful for studying treatment results.

The following types resulted:

Class

Description

Dislocation

Crowe I

Femur and acetabulum show minimal abnormal development.

Less than 50% dislocation

Crowe II

The acetabulum shows abnormal development.

50% to 75% dislocation

Crowe III

The acetabula is developed without a roof. A false acetabulum develops opposite the dislocated femur head position. The joint is fully dislocated.

75% to 100% dislocation

Crowe IV

The acetabulum is insufficiently developed. Since the femur is positioned high up on the pelvis this class is also known as "high hip dislocation".

More than 100% dislocation

Incidence
Determining the incidence can be difficult, because many cases appear to spontaneously resolve. In addition there is a wide margin in diagnostic results. A German study comparing two methods resulted in twice the usual rate for one method.
An instability rate of 1:60 has been described, though this rate drops to 1:240 at one week. The condition occurs with higher frequency in females than in males.

 

 

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