Comparison of normal and abnormal human fetal hip joints: a quantitative study with significance to congenital hip disease.

The presence, extent of abnormality, and measurement data in hips from six fetuses with congenital deformities and seven normal fetuses with 12 aberrant hips were compared with similar data from 140 normal fetuses. Six hips were abnormal on naked eye examination in fetuses with polycystic kidneys, multiple deformities, or cyclopia. Hips graded normal in two fetuses with cardiac defects were found to have dysplasia, greater on the left side, when measurement data were compared. Aberrant features observed resembled that reported in congenital hip disease. Although no joints were frankly dislocated, six hips were subluxated with marked deformity. Only two assessed abnormal hips did not have values outside normal limits for their comparison age group, and joints from six fetuses had some values that exceeded normal limits by 2 SD. In only two fetuses were the femoral angle values outside normal limits indicating that femoral angles alone may be poor criteria of hip dysplasia. Quantitative data for normal fetuses permit more precise evaluation of morphologically abnormal joints and enable detection of dysplasia not apparent on naked eye examination.