Management of clinically stable hips with an increased age-related acetabular index (AI) remains controversial. The authors' purpose was to document the natural history of such hips. Sixty-eight clinically stable hips with an increased age-related AI were followed up for a mean of 9.5 years. Four patterns of evolution were observed: type 1 (25 hips) had rapid progression to normal range in the first 2 years; type 2 (19 hips) had slow improvement, with AI values reaching the normal range between 4 and 11 years; type 3 (20 hips) had improved hip morphology with persistence of minor deviations from the normal values; and type 4 (4 hips) showed no improvement. Initially, none of the hips with type 1, 2, or 3 pattern showed radiologic signs of displacement; in contrast, all our type 4 hips were radiologically eccentered. Clinically stable and radiologically well-centered hips with an increased age-related AI improved spontaneously without treatment. For these cases, clinical and radiologic follow-up is all that is needed.
Study conducted at Réné Descartes University, Medical Faculty, Cochin-Port Royal, Saint Vincent de Paul Hospital, Paris, France
From the Department of Pediatric Orthopedic Surgery, Saint Vincent de Paul Hospital, Paris, France.
Address correspondence and reprint requests to R. Seringe, Chairman, Department of Pediatric Orthopedic Surgery, Saint Vincent de Paul Hospital, 74-82, av. Denfert-Rochereau, 75014 Paris, France (e-mail: Raphael.Seringe@ap-hop-paris.fr).
None of the authors received financial support for this study.