STUDY DESIGN: Thirty-two postmenopausal female patients, with the facet angle less than 40 degrees, were selected for this study. All patients underwent spinal surgery. Displacement group, diagnosed by the displacement of facet joint above 2mm was noted in 15 patients. Control group had 17 patients and was defined when the displacement of facet joint was less than 2mm. OBJECTIVES: Our study evaluated the expression of estrogen receptor and degenerative change depending on the displacement of facet joints. SUMMARY OF LITERATURE REVIEW : Despite the fact that degenerative spondylolisthesis is more common in female than in male, a few attempts have been made to evaluate estrogen as one of the predisposing factors for displacement of facet joint. MATERIALS AND METHODS: After harvesting the articular cartilage of facet joint, the expression of estrogen receptors was evaluated with immunohistochemical staining, and the degenerative change of the articular cartilage with hematoxylin-eosin and alcian blue staining. RESULTS: All facets showed a positive correlation between the estrogen receptor scores and histological-histochemical scores(r=0.78, p<0.05). The average score of the estrogen receptors was 9.1+/-0.4SEM in displacement group, and 5.0+/-0.6SEM in control group(p<0.05). The histological-histochemical grading of cartilage lesion was 12.4+/-0.6SEM in displacement group, 8.0+/-0.3SEM in control group(p<0.05). CONCLUSIONS : This study suggest that a high expression of estrogen receptors, which affected the severity of degenerative changes in facet articular cartilage, might be one of the predisposing factors for the displacement of facet joint.