Ineffective hip rotation with Pavlik harness. Prospective study of 35 infant dislocations.

35 hips in 31 infants diagnosed as unstable were treated with a Pavlik harness and followed by weekly clinical and monthly ultrasound evaluation to determine eventual stability. 26 hips became stable within 3 months, and 9 dislocations required reduction with hip spica placement; 1 of these subsequently required open reduction. Of the 7 infants with 9 hips that failed, 2 children had a late onset of treatment, 2 children had problems with brace fit or family acceptance, and 3 other children had no problem with use of the orthosis. Internal rotation of a degree not possible with the Pavlik harness was required to reduce 4 of these 9 hips. The Pavlik harness is ineffective in some patients because of the need for internal rotation.