ULTRASOUND OF INFANTILE HIPS – ARE GRAF IIA+ HIPS REALLY BENIGN?

Abstract

Background and Aim: Developmental dysplasia of the hips covers a wide spectrum of hips scenario ranging from mild subluxation to frank dislocation. Sonographic examination has been a widely accepted method of screening and monitoring treatment. Graf IIa+ hips are believed to indicate physiological immaturity with alpha angles appropriate for age and are expected to develop normally without any treatment. The aim of this study was to assess the final outcome of sonographically proven Graf IIa+ hips and to identify any factors which may influence the progression of dysplasia in this group of children.

Materials and methods: Over a six year period, 19,170 new born babies were assessed for DDH. 393 infants with high risk factors and clinical abnormality of the hips underwent ultrasound examination. The scans were performed and reported according to Graf Technique. Pavlik harness treatment was instituted as indicated. Seventy four hips in 44 children were classified as Graf IIa+. Patients who had the hips scans before four weeks and those with incomplete medical records were excluded. All children had regular follow-up with a pelvic x-ray. Acetabular Index (AI), Reimers Index (RI) and Centre edge (CE) angle was measured. All children were followed up until their hips were clinically or radiologically satisfactory. The results were analysed using SPSS software.

Results: Thirty six children with 60 Graf IIa+ hips were eligible for this study. There were 28 girls with 46 hips and eight boys with 14 hips (Girls: Boys = 3.5:1). 29 Left hip and 31 right hip were involved. At a mean follow up of 13 months (range 6 – 41months), the AI was normal in 62%, mildly dysplastic in 30% and severly dysplastic in 8% of the hips. The Reimers Index was normal in 73%, sub-optimal in 24% and subluxated in 3% of the hips. The CE angle was normal in 65%, mildly pathological in 23% and moderately pathological in 12% of the hips. Limitation of abduction after 48hrs of birth appeared to have a direct effect on the development of dysplasia (p=0.02)

Conclusion: From our study, we believe that hips with Graf IIa+ scans are not as benign as they were thought to be. When associated with limited abduction after 48 hours of birth, a high index of suspicion and a long term follow up may be prudent.