The Dorr Type and Cortical Thickness Index Just Below the Lesser Trochanter and Its Comparison with Cortical Thickness Index Ten Centimeters Below the Tip of the Lesser Trochanter: A Cross-Sectional Study

Quality of the bone before surgery determines the choice of the appropriate prosthesis and the surgical approach as well as the result of total hip arthroplasty (THA). The proximal femur morphology determines the decision of cemented or uncemented THA, and the Dorr classification is often employed for this purpose.

100 patients over the age of 40 who had been referred to the emergency department of Shohada Hospital, Tabriz, Iran, for any reason and had an accurate pelvic anteroposterior (AP) X-ray with proximal femur were included in this study, and Dorr classification and mean cortical thickness index (CTI) just below the lesser trochanter and 10 cm below it were measured.

In this study, the Dorr classification differed significantly in men and women, and type C was higher in women. Classification is strongly subjected to the surgeon's clinical experience, and training class significantly affects it. There was a significant relationship (P < 0.001) between the CTI 10 cm below the trochanter and just below it.

The proximal femur morphology covers a wide range. Therefore, it is difficult to determine the exact morphology, especially for groups B and C. There was also a significant correlation between the mean CTI below the lesser trochanter and 10 cm below it. Therefore, we think this is a practical and most straightforward method for classifying proximal femur morphology with cortical index (CI) just below the lesser trochanter and 10 cm below it, especially for inexperienced training residents.