Assessment of femoral neck-shaft and antetorsion angles.

The biplanar (Rippstein/Dunlop) technique is commonly used to radiographically determine the neck-shaft and anteversion angles of the hip. This method is unsuitable for certain groups of patients, such as those with fixed contracture of the hip joint. In these patients we have found the 'sinus wave' method to be preferable. We compared the neck shaft and anteversion angles of 30 hips determined by these two methods. Correlation was good for both the neck shaft (r = 0.972) and anteversion angles (0.69). We also used ultrasound to measure the anteversion but this correlated poorly with the Rippstein/Dunlop technique (r = 0.56). We believe that the sound wave technique is an accurate and practical way to determine the anteversion and neck-shaft angles of the hip.