We compared the clinical and radiological effects of the Salter and the Chiari pelvic osteotomy on congruent dysplastic adolescent hips with mild symptoms and free of degenerative changes. The Salter innominate osteotomy has a significant role in the surgery of paediatric hips with significant elasticity of triradiate cartilage, while the Chiari procedure is reserved for incongruent dysplasia with mild or moderate arthrosis in adolescents or young adults. Neither of these operative procedures is an ideal indication for congruent dysplastic adolescent hips free of arthrosis. Hypothetically, the residual remodelling potentials of immature congruent dysplastic adolescent hips can be sufficient to overcome the disadvantages of the Salter and the Chiari osteotomy and give good, long-lasting results. The effects of these quite different procedures in two homologous groups were compared. There were 30 hips treated with Chiari and 25 hips corrected by Salter osteotomy. All hips were congruently dysplastic according to the distance between the centres of the femoral head and the acetabulum (Klaue et al., classification). Groups were homologous considering mean age (14.5 years), follow-up period (8.5 years), presence of preoperative pain, Trendelenburg sign, and degenerative changes. Assessment for pain and Trendelenburg sign was made at follow-up. Radiological measurement was made of the central-edge angle of Wiberg (CE), acetabular angle of Sharp (AAS), and the femoral head coverage index of Heyman and Herndon (FHC). Progression of degenerative changes was analysed according to the criteria of Kellgren and Lawrence. At follow-up in the Chiari group, presence of pain was reduced from 54% to 6.6%, and from 35% to 12% in the Salter group. The presence of Trendelenburg sign was reduced 3% in the Chiari group and remained the same in the Salter group. At control, mean values of radiological parameters were normal in both groups (Salter: CE-27.8°, AIS-36.8°, ING-82.8%; Chiari: CE-36.8°; AIS-39.7°; ING-90.8%). Individual analysis showed 16% of dysplastic hips in the Salter group, and none in the Chiari group. Only one hip (4%) had grade 1 arthrosis after Salter osteotomy. There were five grade 1 hips (17%) in the Chiari group and one (3%) grade 2 arthrotic hip. At follow-up (mean 8.5 years) greater reduction of pain was found in the Chiari group than in the Salter group, but the presence of Trendelenburg sign remained almost unchanged in both groups. There was normalisation of the mean values of radiological parameters in both groups, but the Salter osteotomy was unable to correct dysplasia in 16% of the adolescent hips. Progression of degenerative changes was more rapid in the Chiari group.
