Pelvic obliquity as a factor in dysplastic hip in infancy

Screening of the newborn to detect hip dysplasia has led to the increasing recognition of fixed pelvic obliquity, in which one hip has restriction of abduction and the other, restriction of adduction. The hip with limited abduction is apparently short, so that the infant presents signs clinically indistinguishable from those of congenital dislocation. During the years 1974-78, 192 consecutive cases of unilateral dysplastic hips were treated by us; 44 (23%) were diagnosed as having pelvic obliquity. Nine were males and 35, females; 39 were firstborn. A characteristic postural pattern was found on examination. If untreated in the early stages, a morbid degree of subluxation developed and in six cases, complete dislocation occurred. In 33 cases, complete resolution of abduction contracture and subsequent pelvic obliquity occurred within the first year of life. In a number of cases, pelvic obliquity persisted for years and in a few, resulted in physical incapacity.