The Basic Research And Clinical Studies Of High Hip Centre In THA

Objective: To compare the accuracy of the two methods (Ranawat's and Pierchon's) used to determine the position of the centre of rotation of the hipMethods: Selecting 30 patients with unilateral osteoarthritis of the hip. An anteroposterior (AP) radiograph of the pelvis was taken with the patient positioned supine and, 3 months later the total hip arthroplasty, the AP radiograph was repeated. The centre of rotation of the healthy hip was determined by superimposing a template circles. After confirming that the centre of rotation had not varied from the preoperative to the postoperative radiographic study, we applied Ranawat's and Pierchon's methods to the preoperative projection to ascertain which of them determined a centre of rotation closer to the anatomical centre measured by calculated with the template circles.Results: When the values of the healthy hip are compared with those obtained by using the Ranawat's method, highly significant differences are observed for both X (P<0.0001) and Y (P<0.0001). When the results of the healthy hip are compared with the values obtained by using the Pierchon's method, neither the X (P=0.722 ) nor the Y values (P=0.112) show any significant differences.Conclusions: It would be advisable to use Pierchon's method to determine the anatomical centre of rotation during the preoperative planning for a total hip arthroplasty when the anatomical alteration is bilateral.