Mechanoreceptor evaluation of hip joint capsule and ligamentum capitis femoris in developmental hip dysplasia: a preliminary study.

We aimed to determine if there are mechanoreceptors in the hip joint capsule and ligamentum capitis femoris (LCF) of patients with developmental dysplasia of the hip (DDH). We took capsule and LCF biopsies from 20 hips of 20 patients who were operated on because of DDH. The mean age was 10.2 months (range 6-20 months) at the time of surgery. There were 12 girls and eight boys. Teratologic and secondary hip dislocations were not included in this study. Full thickness, 0.5 x 0.5 cm anterior capsule and LCF portions were taken for biopsy specimen. Specimens were stained with hemotoxylin eosin and examined immunohistochemically using monoclonal antibody against S-100 protein. In both analyses no mechanoreceptor was found in any samples of capsule or LCF. In this preliminary study we could not find mechanoreceptors in the local anterior joint capsule and LCF of the hip in children with DDH. We think that additional studies are necessary in order to understand the mechanoreceptor characteristics of the hip joint in children not only with DDH but also in children with healthy hips.