Dynamic hip screw is still one of the most widely used devices for the fixation of femoral intertrochanteric fractures. A recognized complication with this device is the screw cut-out from the femoral head.
Of this study is to assess if the tip apex distance is a reliable predicting factor for the subsequent lag screw position and so the outcome of femoral intertrochanteric fractures fixed by dynamic hip screws.
Design of the study: Prospective Cohort Study.
PATIENTS AND METHODS:
42 patients (27 female, 15 male), with an average age of 63 years, (ranging from 55 to 72 years),with stable intertrochanteric fractures of the femur treated by dynamic hip screws. All patients were investigated and optimized for surgery. Good and accepted closed reduction was done under fluoroscopic control with the use of orthopedic table. Dynamic hip screws were inserted by a standard technique. Tip apex distance for every case was measured by immediate postoperative plain x-ray.Patients were reviewed clinically and radiologically on 2nd, 6th, 12th, and 24th weeks.
Setting: department of orthopedic-medical city complex and private job.
There were 30 cases (71.4 %) with tip apex distance below 25 millimeters. Only 1 case of them ended with mechanical failure. And there were 12 cases (28.6 %) with tip apex distance more than 25 millimeters. 5 cases out of these 12 cases ended with mechanical failure. So the mechanical failure represented 41.7 % when the tip apex distance was more than 25 millimeters while it was 3.3 % when the tip apex distance was below 25 millimeters. The two-tailed P value equals 0.0047
it is concluded that the tip apex distance is a strong predicting factor for the mechanical failure of stable intertrochanteric fracture of the femur fixed by dynamic hip screw.