[Practical significance of sonographic type IIa of dysplastic hip joint according to Graf's classifications]

Hip joint assessment in newborns and neonates is currently performed with ultrasonography due to the high degree of sensitivity and specificity of this technology as compared to the usual radiography. Measuring the alpha and beta angles is indicative in assessing the hip joint. The alpha angle represents the bony acetabular components and the beta angle represents the cartilaginous roof. According to Graf's classifications, type IIa is subdivided into two subgroups; type IIa- and IIa+. This study examined the need for following-up on these hip joints in newborn and neonate. The study population included the newborns and neonates born in our facility between the period 1/1/1999 to 1/4/2002. We routinely screened 10,432 newborns both clinically and ultrasonographically. This included a total of 20,862 hip joints, of which 915 were pathological according to Graf's classifications. Type IIa was diagnosed in 232 newborns and a total of 330 hip joints. The follow-up examinations were performed at 6 and 12 weeks of age, and at six months of age. Each follow-up visit included clinical and sonographic evaluation and alpha angle measuring. The incidence of type IIa was 1.6% of all hips and 36.9% of the pathological hip joints. These joints were divided into two subgroups. Group A included 254 hip joints among 156 newborns, 116 girls [74.3%] and 40 boys [25.6%]. Group A members had bilateral or unilateral type IIa hip joints. In the latter case, the other joint was type I-normal. Group B included 76 hip joints among 76 newborns, 72 girls [94.5%] and four boys [5.5%]. Group B members had one type IIa hip joint and a second more severely graded hip joint. Follow-up only was required in 88% of the type IIa hip joints and 12% were treated using Pavlik's method. Surprisingly, all the joints with unilateral type IIa hips developed into normal or type I by six months of age without treatment, independent of the alpha angle value, and the pathology on the opposite side.