Estrogen receptors in hip joint capsule and ligamentum capitis femoris of babies with developmental dysplasia of the hip.

OBJECTIVE The aim of this study was to detect the incidence of estrogen receptors in human hip joint capsule and ligamentum teres. METHODS The study included biopsies of the ligamentum capitis femoris (LCF) and hip joint capsule from 15 patients undergoing hip surgery for developmental dysplasia of the hip (DDH) and from the control hips of 15 cases of intrauterine fetal death. Mean age was 10.3 (range: 6 to 18) months at the time of surgery. Full-thickness 1x1 cm anterior capsule and LCF portions were taken as biopsy specimens. An immunohistochemical study using monoclonal antibody against estrogen receptors was performed to identify the rate of target estrogen cells in the hip joint capsule and LCF. RESULTS Estrogen receptor (ER) staining rates were 1.6±0.2% for the LCF and 1.3±0.2% for the hip joint capsule in the control groups, and 2.5±0.3% for the LCF and 2.0±0.3% for the hip joint capsule in the DDH groups. Estrogen receptor staining rates in the LCF and hip joint capsule control groups were significantly lower than that in the DDH groups (p<0.001). In both groups, ER rates were significantly lower in the hip joint capsule than in the LCF (p<0.01). CONCLUSION The high rate of ERs in the LCF and hip joint capsule appears to support the effect of estrogen in the etiology of the DDH.